text:
When working with shapes in math class, students learn a new vocabulary. Among the terms they use are "length" and "width." To correctly solve geometry problems, students must correctly identify them. Using the basic shapes of rectangles and triangles, students can learn how to apply these terms to their mathematics classes.
Identify length and width with "horizontal" and "vertical." For rectangles in particular, the length is the horizontal side, while the width is the vertical side. This can be confusing, as the length is not necessarily the longest side, as one might expect.
Understand the implications of length and width for rectangles. The distinction between length and width has few real consequences for rectangles, as finding a rectangle's area involves multiplying them (making order irrelevant) and finding its perimeter involves adding all four sides together (where order is also irrelevant).
Apply this knowledge to triangles. Triangles have a specialized vocabulary: the length, or the bottom horizontal segment, is known as the base; the width is known as the height, measured from the uppermost point of the triangle to the base. This is because the length and width of a triangle varies as you progress through the shape, so using the terms "base" and "height" to describe these aspects of a triangle prevents confusion.
- Photo Credit Hemera Technologies/AbleStock.com/Getty Images
You May Also Like
How Is Geometry Used in Real Life?
Some skyscrapers have windows made of rectangles and squares. ... Connecting geometry concepts to real life helps students better understand the subject.
The Quadrilaterals Used in Everyday Life
Hi, my name is Marija, I'm a mathematician and today, we're going to talk about quadrilaterals in real life. So, a quadrilateral...
How to Find the Area of a Rectangle
A rectangle is one of the most common geometric shapes. ... Finding the area of a rectangle is a relatively simple task...
A Real Life Problem of a Square Root Function
Square root functions have a number of different real life applications. Learn about a real life problem of a square root function...
Everyday Examples of Prisms
Life Skills Gadget Guide. eHow; Hobbies ... the only real requirement to qualify as a prism is that the object should have...
What Are the Applications of Quadratic Equations?
Real Life Parabola Examples; How to ... How to Use Quadratic Equations to Solve for the Sides of a Rectangle. Many real-world...
How to Find the Ratio of a Rectangle in Geometry
Rectangles have four sides, and generally the adjacent sides are not equal. Knowing the measurements of the two sides allows you to...
Real Life Parabola Examples
The parabola appears when graphing a quadratic equation, which in its basic form can be written as y=x^2. The shape occurs naturally...
How to Find the Area & Width of a Rectangle
A rectangle is a geometric shape ... Knowing how to apply formulas that relate to rectangles also comes in handy if you...
How to Use a Coordinate Plane in Real Life
How to Use a Coordinate Plane in Real Life. ... How to Find the Area & Perimeter of a Square on a...
How to Solve Algebraic Equations for Rectangles
Solve algebraic equations for rectangles with help from a longtime mathematics educator in this free video clip. ... How to Use Algebra...


text:
Tuesday, 25 October 2016
The markwitton.com H. P. Lovecraft Halloween Special
The best holiday of the year is just around the corner: Halloween! It's the season to celebrate the macabre, the weird, the dark and the terrifying. It's the best excuse to watch all your favourite horror movies. And it's the time to spend hours making costumes that you can't really see out of or eat or drink in, but that's OK because you're doing this for the art, not the practicality. Yes, it's Halloween: king of the holidays.
This year, an impending honeymoon and my attendance at Dinosaur Days 2016 (a palaeontology/palaeoart event being held at the WWT Wetland Centre, London, 28-29th October - it's going to be awesome, and you should come along) means I can't celebrate Halloween as normal. But dammit, I'm going to do something, even if that means just celebrating a little here by sharing some off-topic art.
Sometimes, very rarely, I take a break from painting and writing about palaeontology and turn my attention to vintage science fiction, producing paintings of some of my favourite stories, characters or monsters, and the creatures of H. P. Lovecraft are a frequent subject. With Halloween being just around the corner and Lovecraft's tales of sinister cults, strange creatures and other-worldly horrors being pretty note-perfect fodder for this time of year, I'm going to take the blog off-road with a short gallery of my Lovecraft paintings. Although we're going to be pretty palaeontology-lite for this post (folks here for coverage of extinct creatures may be pleased to know we'll be back to normal very soon) we're not abandoning the concepts of biology and evolution altogether. One of the things I find appealing about Lovecraft's work is the frequent nods to biology, geology and evolution, and creating biologically plausible(ish) versions of his creatures was a primary goal of the work shared here. We're not quite in the territory of full-on speculative evolution with this post, but I've tried to make my discussion at least a little informed. Right, enough preamble, let's get stuck in. (Oh, and a major SPOILER WARNING for those of you who haven't read Lovecraft's most famous stories and books.)
Sunday, 9 October 2016
Exposed teeth in dinosaurs, sabre-tooths and everything else: thoughts for artists
|Bear-sized gorgonopsid Inostrancevia latifrons. Sabre-teeth? What sabre teeth?
Many words – mostly published at blogs, online mailing lists and social media - have been typed to discuss the credibility of lipless palaeoart, but the subject has traditionally received only cursory attention from academics. Happily for artists, this is starting to change. A small set of literature exists which debates the presence of extra-oral tissues in dinosaurs (e.g. Ford 1997; Knoll 2008; Morhardt 2009; Keilor 2013; Reisz and Larson 2016), and most this agrees that some sort of soft-tissue - at least 'lips' - covered their teeth. However, a running theme of these works is that reliably inferring soft-tissues of the face is not a simple task, and we really need more data to be sure of anything. Work on more recent fossil mammals shows more reliable inferences (e.g. Wall 1980; Antón et al. 1998), obviously benefiting from soft-tissue data from a range of extant, close relatives. New insights on the evolution of mammal cranial nerves are helping to understand the development of sensitive lips and cheeks in stem-mammals (Benoit et al. 2016). It's still early days for understanding fossil facial tissues, but at least it feels like we're off the line.
Collectively, there seems to be recognition among the academics interested in this topic that understanding the tooth coverage of fossil animals lies largely in understanding living animals. Attempts to understand tooth exposure from skulls alone - through making inferences about tooth size, jaw closure and speculations on how extensive soft-tissues can be before they become untenable - do not consider all necessary data. For example, Prehistoric Times palaeoart adviser Tracy Ford (1997) looked solely at the skulls of predatory dinosaurs to infer the absence of lips, suggesting their teeth were so long that they would pierce lip sheathing once the jaws were closed. This study assumed that predatory dinosaurs closed their mouths to the extent that the teeth of the lower jaw contacted the roof of the mouth, and that the preserved tooth configuration was the condition in life. These points are common issues raised against lipped dinosaurs, but there are several major problems. Dissections and CT scans of reptile heads show that jaw muscles and other soft-tissues have a major influence on mouth closure, to the extent that reptile jaw skeletons are typically loosely closed under their skin, even when the mouth is fully sealed. Taphonomic studies show that teeth slip readily from their sockets after death and often fossilise in far more vampiric states than they were in life. And undermining this further is that no extant taxa with lipped jaws were used to calibrate a limit for oral soft-tissues. Arguments about tooth coverage based on simply looking at skulls, without detailed consideration of modern animals and their anatomy, border on being arguments from incredulity : "I don't believe the anatomy could do that."
Modern animals and their tooth coverageFor an upcoming project, I've been trying to crystallise my approach to restoring ancient animal facial tissues, and deciding whether to cover their teeth or not is an important part of that discussion. I've been deliberately broad in this assessment to attempt to try to sort the wood from the trees: discussions of oral tissues can sometimes get lost in the minutiae of tissue types, uncertain osteological correlates and so on - and many of these discussions result in the same answer: they can't be resolved with current data. That's not to say they aren't important discussions, but it's helpful to step back to see if we can answer the simpler questions as well: what gauge of teeth can be covered by oral tissues? When are teeth actually exposed? And what questions should we, as palaeoartists, be looking to answer when restoring facial tissues?
Reviewing literature and galleries of modern animals, we can see that overwhelming majority of living tetrapods have covered teeth, including all amphibians, most mammals and most reptiles (excluding birds, naturally. Hey, if they wanted to be involved they shouldn't have lost their teeth). Exposed teeth are actually really rare, and a character completely absent in many major clades. The soft-tissues involved in covering the teeth are variable, but 'lips' – either slightly fleshy margins of skin, or skin overlying true muscle - are so universal among tetrapods, as well as living relatives like lungfish, that we might assume lip tissues of some kind were ancestral to the group, and breaching these with large teeth is a derived condition evolved independently in a minority of lineages. Crocodylians are the only living tetrapods with fully exposed teeth, but it's increasingly obvious that they're also pretty specialised/derived/downright weird (Grigg and Kirshner 2015). Far from being 'living fossils' frozen in evolution, they have so many anatomical nuances and specialisations that their use as model organisms for other extinct taxa is increasingly questionable. This applies to aspects of their facial anatomy too - we'll discuss this in more detail below.
We owe many of these surprises to animal lips, which are generally much more extensive than we casually assume. Large teeth can slide into soft-tissue sheaths located between gums and lips, and these are quite visible in the open mouths of some species. Amphibians, lizards and many mammals have upper and lower lips of similar size which meet over the teeth and sheaths can form on either jaw, but some mammals – including most carnivorous forms - have very large, fleshy upper lips over thinner, tightly-bound soft-tissues of the lower jaw (Antón et al. 1998). In these species, the canine teeth overbite the lower lip but the upper 'over-lip' is large enough to obscure the fact that the tooth is outside the lower mouth tissues. I am unaware of a reversed situation with the lower lip covering a thin upper lip: this may reflect the fact that overbiting dentition is much more common than underbiting. Regardless of the specific configuration, it is clear that we should not underestimate the capacity for facial tissues to obscure even very large, sharp and ferocious-looking teeth. The assumption that all conspicuous teeth of fossil animals were on display in life is thus problematic and does not agree with what we can observe in modern animals (below).
What's up with crocodylians?The elephants – or rather large semi-aquatic reptiles – in the room here are crocodylians: why do they have exposed teeth when all other tetrapods have largely covered mouths? Their teeth are not overly large, nor acutely angled. Some (Reisz and Larson 2016) have argued crocodylian dentition is only possible because of their semi-aquatic habits. The (unpublished, currently conference abstract only) Reisz and Larson hypothesis is that exposed teeth – specifically their enamel component – are at risk from desiccation and breakage without constant hydration from saliva or environmental water (Reisz et al. 2016). This is an interesting idea which potentially gives artists a useful, practical guide to restoring prehistoric animals: anything living outside water with enamel-covered teeth must have covered them with soft-tissue. Despite its unpublished status, this idea has already chimed with some quarters of the online palaeoart community who're restoring anything with enamel-covered teeth with full sheathing.
|Musk deer, Moschus, canines in lateral and medial view. Note the (white) enamel layer on the lateral surface, but dentine (grey) on the medial. From Hillson (2005 - the scale bar is likely erroneous!).
Furthermore, there are important caveats about crocodylian facial tissues that we have to factor into any discussion of their lipless configuration. Crocodylian faces are far more specialised and unusual than they first appear, and this may factor into their lipless mouths. Their highly keratinous facial skin undergoes a developmental pathway unlike that of any other amniote (their facial skin is essentially have one, highly 'cracked' scale) (Milinkovitch et al. 2013) and their heads are riddled with hyper-sensitive Integumentary Sense Organs (ISOs). ISOs are another unique crocodylian feature and are attuned, among other things, to sensing tiny vibrations in water (Soares 2002, see Grigg and Kirshner 2015 for a recent overview). In at least some parts of the crocodylian skull ISOs are situated over tiny foramina, presumably housing nervous tissues, and the overlying epidermis is thinned, with a reduced keratin component, to enhance their sensitivity (Soares 2002). We can thus see that ISOs do have a role to play in configuring crocodylian skin, and they present many questions that palaeoartists should be interested in. Are ISOs an important reason for crocodylian faces having such tight, contour hugging and lipless skin? Do the major functional and developmental distinctions of croc faces explain the lack of crocodylian lips? It might explain why virtually no other aquatic tetrapods have abandoned lips - aside from the the odd (and perhaps only) exception like the South Asian river dolphin*, there are no whales, snakes, seals or otters with crocodylian-like, fully exposed teeth. And given that no other lineages have osteological correlates for ISOs, should we put huge caveats around using crocodylians as models for facial tissues in anything other than their own ancestors? I don't know if anyone has answers to these questions yet, but they're food for thought when using crocodylians as ammunition for lipless reconstructions of fossil animals.
*Thanks to Ádám Lakatos for pointing out the toothiness of some river dolphins!
It's still very early days for the enamel/oral covering hypothesis, but modern animals suggest that interpretations of enamel precluding extraoral teeth are definitely more complicated than they first appear, and may even be flawed. If so, the simple presence of enamel on the teeth of fossil organisms may not be as useful to artists as some are currently suggesting. But this conclusion is preliminary, and we need to wait for this idea to mature before it's shot down entirely. We know, for instance, that there's more than one type of enamel among vertebrates. Reptilian enamel, for instance, is both thinner and of different microstructure to mammalian enamel, and these clades have rather different approaches to tooth longevity. This may mean something for enamel desiccation and long-term tooth exposure, and we may think differently on this matter once this research has been completed.
Predicting tooth exposure in fossil species
|Fully 'lipped' gorgonopsids and theropods: maybe not be as exciting as their toothy variants, but are they more credible? Well... if modern animals are anything to go by, probably.
If this is so, only especially long teeth which project a considerable distance from the margins of the skull and lower jaw should be considered strong candidates for permanent exposure. Select examples might include the canines of certain mammalian carnivores (e.g. Smilodon and other machairodont felids), the tusks of fossil elephants and their relatives, and the larger tusks of dicynodonts. We should also note those fossil reptiles – such as certain crocodyliformes, pterosaurs and marine reptiles – where entire toothrows are composed of dentition so long that their tips extend well beyond the margins of the jaw skeleton. Such extensive dental apparatus would seem to preclude the development of any sheathing tissues, at least akin to those exhibited by from modern animals, and these animals probably had fully exposed toothrows in life. Of course, this conflicts with the observation that food-processing teeth are almost always covered in the modern day. However, we can defend this approach by arguing that their morphology gives a strong reason for ignoring this guideline: it answers the "why we shouldn't give them lips?" question.
Dunae Nash's recent discussions about sheathing Smilodon: given that this rests heavily on enamel being a no-no in exposed teeth, I'm unconvinced for the reasons explored above.
The concluding caveatOf course, it must be reinforced that these are just guidelines - and guidelines based on my own qualitative studies, nonetheless, your mileage with them may vary - and there are exceptions to the suggestions made above. As is well known, for all the suggestion that restoring sabre-toothed cats with exposed teeth is reasonable, one living cat species – the clouded leopard – does cover a set of long upper canines in a lower lip sheath. We would not predict this based on other cat species and, if known only from fossils, clouded leopards would probably be restored with a slightly exposed canine. Likewise, the exposed tusks of some deer are not especially massive, and if we followed the suggestions above we'd probably cover them up in a reconstruction. But palaeoart is ultimately a game of prediction and probability, attempting to restore what is most likely to fill gaps in our data, and any game of odds will have some failures. That's not to say we shouldn't ignore these exceptional examples - they show that guidelines can't be trusted all the time - but it makes sense for us to know where the guidelines are in the first place. As with all aspects of palaeorestoration, all of us stand a chance to be proved wrong about our artistic decisions: if and when that happens, the best we can hope for is to have been wrong for the right reasons.
This blog post was covered by PatreonThe paintings and words featured here are sponsored by a group of animals which also have sheathed dentition, Patreon backers. Supporting my blog from $1 a month helps me produce researched and detailed articles with paintings to accompany them, and in return you get access to bonus blog content: additional commentary, in-progress sneak-previews of paintings, high-resolution artwork, and even free prints. Sign up to Patreon to get access to this and the rest of my exclusive content!
- Antón, M., Garcia‐Perea, R, & Turner, A. (1998). Reconstructed facial appearance of the sabretoothed felid Smilodon. Zoological Journal of the Linnean Society, 124(4), 369-386.
- Benoit, J., Manger, P. R., & Rubidge, B. S. (2016). Palaeoneurological clues to the evolution of defining mammalian soft tissue traits. Scientific reports, 6.
- Conway, J., Kosemen, C. M., Naish, D., & Hartman, S. (2013). All yesterdays: unique and speculative views of dinosaurs and other prehistoric animals. Irregular Books.
- Ford, T. L. (1997). How to Draw Dinosaurs. Give Theropods no Lip! Prehistoric Times, 25, 49-50.
- Hillson, S. (2005). Teeth, Cambridge Manuals in Archaeology Series. Cambridge University Press, Cambridge, 373.
- Goldfinger, E. (2004). Animal anatomy for artists: The elements of form. OUP USA.
- Grigg, G., & Kirshner, D. (2015). Biology and evolution of crocodylians. Csiro Publishing.
- Keillor, T. (2013). June, in the Flesh: The State of Life-Reconstruction in Paleoart. In: Parrish, J. M., Molnar, R. E., Currie, P. J., & Koppelhus, E. B. (eds). Tyrannosaurid Paleobiology, Indiana University Press. 157-176.
- Kemp, T. S. (2005). The origin and evolution of mammals. Oxford University Press.
- Koenigswald, W. V. (2011). Diversity of hypsodont teeth in mammalian dentitions—construction and classification. Palaeontogr. Abt. A, 294, 63-94.
- Knoll, F. (2008). Buccal soft anatomy in Lesothosaurus (Dinosauria: Ornithischia). Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 248(3), 355-364.
- Morhardt, A. C. (2009). Dinosaur smiles: Do the texture and morphology of the premaxilla, maxilla, and dentary bones of sauropsids provide osteological correlates for inferring extra-oral structures reliably in dinosaurs? (Doctoral dissertation, Western Illinois University).
- Prado, J. L., & Alberdi, M. T. (2008). A cladistic analysis among trilophodont gomphotheres (Mammalia, Proboscidea) with special attention to the South American genera. Palaeontology, 51(4), 903-915.
- Reisz, R. R. & Larson, D. (2016) Dental anatomy and skull length to tooth size rations support the hypothesis that theropod dinosaurs had lips. 2016 Canadian Society of Vertebrate Paleontology Conference Abstracts, 64-65.
- Soares, D. (2002). Neurology: an ancient sensory organ in crocodilians. Nature, 417(6886), 241-242.
- Wall, W. P. (1980). Cranial evidence for a proboscis in Cadurcodon and a review of snout structure in the family Amynodontidae (Perissodactyla, Rhinocerotoidea). Journal of Paleontology, 54, 968-977.
Monday, 12 September 2016
A salute to the Erythrosuchidae
|Two Garjainia madiba decide who gets the table scraps. The reconstructions here are modified from the life reconstruction I provided for Gower et al. (2014).
Alas, erythrosuchids don't get as much love from palaeoartists or outreach projects as they deserve. Their marriage of a proportionally huge, sharp-toothed skull with a crocodile- or lizard-like body is unlike anything around today and it's difficult not to wonder how they functioned as living animals. Closer inspection of their anatomy reveals more sophistication than we might assume from the few illustrations of these animals available online or in books, and it seems that their role in Mesozoic ecosystems and reptile evolution was an important one. These were a successful, abundant group of predators with an evolutionary run spanning the Early and Middle Triassic (12 million years in total) and a near cosmopolitan distribution. Moreover, they remain important species for understanding the early evolution of archosaur-line reptiles. They really do have a lot going for them, but they just haven't quite caught public imagination.
A few years ago I was commissioned to reconstruct the small(ish), early erythrosuchid Garjania madiba for David Gower and his colleagues for their 2014 descriptive paper (below). The brief was for a straight illustration of the animal rather than a restored scene, and I promised the team I would put this reconstruction in a landscape one day. Two years later, I've finally got around to it: the results are above. Posting this painting seems like as good an excuse as any to lavish some much needed attention on these most encephalised of reptiles, so let's get stuck in.
|G. madiba reconstruction from Gower et al. (2014). Note prominent bosses on the face, a characteristic feature of this species.
What, exactly, is a erythrosuchid?You can find erythrosuchids in Triassic rocks on every continent except North America and Antarctica and, although relatively complete specimens are not common, many species are represented by large inventories of bones. Despite this relative glut of material, the classification of erythrosuchids - from the fine anatomical characteristics of the group, to their position in the reptilian tree and the number of species contained in the clade - has been the subject of long-standing, ongoing discussions among palaeontologists. Older erythrosuchid literature is confused by a multitude of different classifications which entwine erythrosuchids with other large-headed, carnivorous archosauriforms such as raisuchians and proterosuchids. Researchers have long realised the problems with these schemes, but unpicking the relationships of these groups and other early archosaur-line reptiles has been tricky. With the arrival of extremely detailed and well sampled cladistic analyses of archosauromorphs (e.g. Nesbitt 2011; Ezcurra 2016) we might be moving towards greater consensus on the systematics of these animals, however. In modern schemes, erythrosuchids are recovered as non-archosaur archosauriforms close(ish) to the base of Archosauria. More specifically, they are the sister clade to the the Eucrocopoda, the large clade that contains the likes of Euparkeria and proterochampsids, as well as the true archosaurs (Ezcurra 2016).
|Erythrosuchus africanus skull, restored by Gower (2003). Note the extremely robust construction of the bones and expanded areas for neck muscle attachment.
Although erythrosuchid skulls were almost certainly pneumatised in some areas, the largest opening in the skull is not, as we might expect in such large headed animals, anything to do with a pneumatic cavity. Rather, it's the lower temporal fenestra, an opening typically associated with allowing bulges of the jaw adductor muscles. This, as well as the presence of a small sagittal crest between the superior temporal openings (which overly the same muscle block) and the depth of the posterior mandible likely betrays the presence of massive adductor muscles in temporal region of the skull. Eryhtrosuchid skull bones certainly look sufficiently robust to withstand powerful biting, the bones forming the temporal fenestra, jaw and orbital margins being extremely massive and thick and tightly interlocking with complex sutures between each bone. Interestingly, Shansisuchus has the same partly invaded orbit shape that Henderson (2003) linked with reinforcement against heavy bite forces in theropod dinosaurs: perhaps similar buttressing was taking place in these Triassic reptiles
|The dorsal extent of the occipital face in Eryhtrosuchus africanus, posterior view. The rounded flanges at the top poke above the rest of the skull, and perhaps indicate expanded neck muscles in this and other species. From Gower (2003).
Behind the skull we see a fairly typical Triassic archosauriform body (below). The neck is short, and especially so in some of the larger species, and the majority of the vertebrae are adorned with tall neural spines: these almost certainly provided anchorage for axial musculature related to supporting the head and back. The pectoral elements, which are also employed somewhat in neck musculature, are also robust. Their tails are moderately long, with deep chevrons in the anterior region likely related to hindlimb musculature. Behind these, the tail becomes rather slender. Gower (2001) proposed that Erythrosuchus vertebrae possessed pits and depressions possibly related to the development of post-cranial pneumaticity, the first found outside of pterosaurs and dinosaurs. This would be a significant find, telling us something of erythrosuchid lung structure as well as the early evolution of postcranial pneumaticity in archosaur-line reptiles. However, both O'Connor (2006) and Butler et al. (2012) argued against this interpretation, noting that the features in question were not associated with internal cavities, thus failing to meet criteria for structures of pneumatic origin. An important caveat to this, however, was raised by Butler et al. (2012): the phenomenon of pneumatic tissues invading vertebrae and other postcranial bones almost certainly did not evolve in one swoop. Its earliest stages may have simply been pneumatic tissues 'pushing' against external bone walls, forming pits and cavities, rather than invading them entirely. If so, the sort of thing Gower (2001) found in Erythrosuchus might be what we'd expect of early stage, postcranial pneumaticity. So while we have to concede that these structures do not meet our current definition of a postcranial pneumatic structure, perhaps we also need to learn more about the early evolution of postcranial pneumaticity before this hypothesis can be ruled out entirely.
|Mounted Garjainia prima skeleton as mounted at the Paleontological Institute, Moscow. Certain aspects of this skeleton are reconstructed or sculpted, so take some details with a pinch of salt. From Ivakhnenko and Kurochkin (2008).
A point of contention among researchers is whether or not erythrosuchids had osteoderms. Two examples of such structures have been found in association with a specimen of Erythrosuchus, but they show no consistency in their morphology (Gower 2003). Moreover, the extensive inventory of Erythrosuchus and other erythrosuchids have yet to show additional evidence of dermal bones (Ezcurra et al. 2013). The safe bet, for the time being at least, is to assume these reptiles did not have osteoderms, and that those previously referred to the group were a fluke association from another animal.
The life and times of Triassic big-headsWe have much to learn about many aspects of erythrosuchid palaeobiology: details of their dietary preferences, locomotor mechanics and likely habitats remain only provisionally researched. Much of what we've learned about their lifestyles comes from 'bigger picture' assessments of Triassic diversity and faunal turnover, so we can only paint a broad-brush picture of their ecology at this time. That's not to say we have no specific palaeobiological insights into these animals, however. For instance, there is consistent histological evidence that erythrosuchids grew quickly, perhaps at rates comparable to pterosaurs and dinosaurs, until they reached reproductive maturity (de Ricqlès et al. 2008; Botha-Brink and Smith 2011; Ezcurra et al. 2013). Given that this trait is not limited to erythrosuchids among Early and Middle Triassic reptiles, this is one reason it's thought that archosaur-line reptiles may not be ancestrally ectothermic. Whatever the cause, rapid growth may have played some role in the success of erythrosuchids and other reptiles as ecosystems were rebuilt in the early Mesozoic (Sookias et al. 2012).
Erythrosuchid ecology remains only lightly investigated, but they have been considered arch terrestrial predators by some (Sennikov 1996 - see below). Interestingly, their size puts them among the largest terrestrial animals known from their respective faunas (Sookias et al. 2012). This is unusual: in post-Middle Triassic ecosystems we generally find herbivores are the largest animals in terrestrial ecosystems, so what's going on here? It's thought that physiological distinctions between large Early-Middle Triassic reptiles and the synapsid herbivores they coexisted with may explain the size difference (briefly summarised, archosauriform growth rates and respiratory anatomy may have permitted larger overall body size than therapsids - see Sookias et al. 2012), but how did this translate into ecological balance? Energy is lost as it is transferred between species in food webs, so how did populations of relatively 'giant' top-tier erythrosuchids sustain themselves on consistently smaller prey? Perhaps they were simply comparatively rare, or very energy-efficient, or maybe they supplemented their diet with non-terrestrial food items - did they also take food from aquatic realms, perhaps?
|An Early Triassic terrestrial food web, reconstructed for the Yarenga Formation by Sennikov (1996). In this scheme, most things ended up in the bellies of erythrosuchids or rausuchians.
In recent years, however, erythrosuchids seem to have been perceived as more terrestrial animals (Sennikov 1996; Botha-Brink and Smith 2011; Ezcurra et al. 2013). Their thick bone walls are explained as being a consequence of their large size rather than aquatic habits (Botha-Brink and Smith 2011) and the deficit of obvious aquatic adaptations in their skeletons has been noted by several authors (Botha-Brink and Smith 2011; Ezcurra et al. 2013; Gower et al. 2014).
|Aquatic, semi-aquatic or fully terrestrial? This guy's meant to have taken a dip in the water, but was it intentional or accident? We may not have the data to say exactly what erythrosuchids did for a living yet.
I love it when a bauplan comes togetherPerhaps one of the most interesting things mentioned recently about erythrosuchids is how little their postcrania differs from those of other archosauriforms, despite their substantial cranial modifications (Ezcurra 2016). This is something we see again and again in Triassic reptiles: relatively conservative bodies with highly localised outlandish anatomy, and is true even for the weirdest Triassic creatures. For example, Tanystropheus isn't that strange aside from its incredible neck, and (what we know of) the body of Sharovipteryx is not that atypical in spite of its leg-wings. I wonder if Triassic animals get the short shrift in popular circles because they're viewed as boring 'also rans' taxa which evolved strange, untenable anatomies but without moving too far from a typically 'reptilian' visage.
But perhaps what we're seeing with these animals is far more interesting than it first appears: a display of the intrinsic adaptability of the archosauromorph bauplan, and how applicable it was to many lifestyles with only localised modification. We can be particularly impressed with erythrosuchids because of their rapid evolution so early in the Triassic: they very quickly and successfully jumped into the niche of large, hypercarnivorous apex-predator after the end-Permian extinction event, and then held that niche worldwide for 12 million years. The fact they did so without much additional modification to the postcrania is evidence that their success was not a fluke, and that the basal archosaur-line body plan was a strong one. Perhaps instead of looking at erythrosuchids and other Triassic archosauromorphs as those strange, but ultimately dull animals that struck it lucky before the more successful ones took over, we might view them as some of the earliest evidence that the archosaur-line bauplan had real potential, and a sign of what was to come.
Big blog posts about big headed reptiles need big support - thank goodness for PatreonThe paintings and words featured here are sponsored by a group of tetrapods with more modestly proportioned skulls, my Patreon backers. Supporting my blog from $1 a month helps me produce researched and detailed articles with paintings to accompany them, and in return you get access to bonus blog content: additional commentary, in-progress sneak-previews of paintings, high-resolution artwork, and even free prints. For this post, we'll be looking at the history of the painting up top, documenting its long 2-year journey from illustration to, er, a more detailed illustration. I'll also share the bizarre, sausage piglet monster version of Garjainia that you were never meant to see. Sign up to Patreon to get access to this and the rest of my exclusive content!
- Botha-Brink, J., & Smith, R. M. (2011). Osteohistology of the Triassic archosauromorphs Prolacerta, Proterosuchus, Euparkeria, and Erythrosuchus from the Karoo Basin of South Africa. Journal of Vertebrate Paleontology, 31(6), 1238-1254.
- Butler, R. J., Barrett, P. M., & Gower, D. J. (2012). Reassessment of the evidence for postcranial skeletal pneumaticity in Triassic archosaurs, and the early evolution of the avian respiratory system. PloS one, 7(3), e34094.
- de Ricqlès, A., Padian, K., Knoll, F., & Horner, J. R. (2008). On the origin of high growth rates in archosaurs and their ancient relatives: Complementary histological studies on Triassic archosauriforms and the problem of a "phylogenetic signal" in bone histology. In Annales de paleontologie (Vol. 2, No. 94, pp. 57-76).
- Ezcurra, M. D., Butler, R. J., & Gower, D. J. (2013). 'Proterosuchia': the origin and early history of Archosauriformes. Geological Society, London, Special Publications, 379(1), 9-33.
- Ezcurra, M. D. (2016). The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms. PeerJ, 4, e1778.
- Gower, D. J. (1996). The tarsus of erythrosuchid archosaurs, and implications for early diapsid phylogeny. Zoological Journal of the Linnean Society, 116(4), 347-375.
- Gower, D. J. (2001). Possible postcranial pneumaticity in the last common ancestor of birds and crocodilians: evidence from Erythrosuchus and other Mesozoic archosaurs. Naturwissenschaften, 88(3), 119-122.
- Gower, D. J. 2003, Osteology of the early archosaurian reptile Erythrosuchus africanus, Broom. Annals of the South African Museum, 110(1), 1 - 84.
- Gower, D. J., Hancox, P. J., Botha-Brink, J., Sennikov, A. G., & Butler, R. J. (2014). A new species of Garjainia Ochev, 1958 (Diapsida: Archosauriformes: Erythrosuchidae) from the Early Triassic of South Africa. PloS one, 9(11), e111154.
- Henderson, D. M. (2003). The eyes have it: the sizes, shapes, and orientations of theropod orbits as indicators of skull strength and bite force. Journal of Vertebrate Paleontology, 22(4), 766-778.
- Ivakhnenko, M. F. & Kurochkin, E. N. (eds.) 2008. Fossil Vertebrates of Russia and adjacent countries. Fossil reptiles and birds. Part 1: A. Reference book for paleontologists, biologists and geologists. GEOS, 2008, 348 pp.
- Nesbitt, S. J. (2011). The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades. Bulletin of the American Museum of Natural History, 1-292.
- O'Connor, P. M. (2006). Postcranial pneumaticity: An evaluation of soft‐tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs. Journal of Morphology, 267(10), 1199-1226.
- Parrish, J. M. (1992). Phylogeny of the Erythrosuchidae (Reptilia: Archosauriformes). Journal of Vertebrate Paleontology, 12(1), 93-102.
- Paul, G. S. (1988). Predatory dinosaurs of the world: a complete illustrated guide. Simon & Schuster.
- Pickford, M. (1995). Karoo Supergroup palaeontology of Namibia and brief description of a thecodont from Omingonde. Palaeontologia Africana, 32, 51-66
- Sennikov, A. G. (1996). Evolution of the Permian and Triassic tetrapod communities of Eastern Europe. Palaeogeography, Palaeoclimatology, Palaeoecology, 120(3), 331-351.
- Reig, O. A. (1970). The Proterosuchia and the early evolution of the archosaurs; an essay about the origin of a major taxon. Bulletin of the Museum of Comparative Zoology, 139(5), 229-292.
Wednesday, 31 August 2016
New paper: at last, a small pterosaur species from the latest Cretaceous
As the Cretaceous fossil record enters its final two stages - the Campanian and Maastrichtian - several unusual things seem to happen in the world of flying reptiles. Firstly, we see the end result of a steady drop off in pterosaur diversity leaving only azhdarchids - those often long-necked, long faced animals that we cover here with some regularity - with a strong, widespread fossil record. It's known that nyctosaurids and (thanks to recent discoveries) perhaps pteranodontids survived until the very end of the Mesozoic in at least two locations, but azhdarchids are globally distributed and dominate the pterosaur fossil record at this time. The overwhelming precedence of azhdarchids in the Late Cretaceous is an anomaly: at no other point in the pterosaur fossil record does one clade feature so prominently.
Secondly, Campanian and Maastrichtian pterosaurs are, without exception, pretty big animals. Many species from this time are renowned for their gigantic size: it's these stages which give us the famous 10 m wingspan, 250 kg colossi like Quetzalcoatlus, Arambourgiania and Hatzegopteryx, as well as a number of other giant azhdarchids which are too poorly known for generic titles. Coinciding with the evolution of the giants is a loss of small pterosaur taxa - those animals less than 2.5 m across the wings which are present, more-or-less, throughout the rest of pterosaur history. This shift in body size is sometimes interpreted as pterosaurs demonstrating 'Cope's Rule', the somewhat controversial proposal that species evolve towards large body size over time (Hone and Benton 2007; Benson et al. 2014). It's argued by some that competition from birds may be the driver behind this trend, as early avians fought small flying reptiles for ecological space and ultimately forced pterosaurs into larger sizes (e.g. Benson et al. 2014). Note that this concept is not without its detractors, including myself - I won't go into my reasons now but I plan to outline them here eventually.
Whether you agree with the bird-pterosaur competitive displacement hypothesis or not, we can't disagree that the end of the Cretaceous is almost entirely devoid of small pterosaur remains. Only a handful of specimens record small pterosaurs in the Campanian and Maastrichtian, and they're all tricky to work with. Aside from being highly fragmentary, some are controversially identified (such as Piksi barbarulna, an alleged small pterosaur from the Two Medicine Formation - see Agnolin and Varricho 2012 for the pro-pterosaur case) and others represent probable juvenile individuals (Godfrey and Currie 2005). Whatever it signifies, the lack of diminutive pterosaur specimens from the close of the Mesozoic is a real phenomenon of our fossil record, and any new specimen of a small, latest Cretaceous flying reptile has to be something to get excited about.
It's this point where a new paper, published today by Liz Martin-Silverstone, myself, Victoria Arbour and Phil Currie comes in. Our new work, which you can check out without restriction at the open access journal Royal Society Open Science, presents a new small pterosaur fossil from the Campanian Northumberland Formation of British Columbia. The specimen number - RBCM.EH.2009.019.0001 - is pretty unwieldy, so I've been calling it the 'Hornby azhdarchoid' or the 'Hornby pterosaur' after it's discovery on Hornby Island, just off the coast of Vancouver. As you can see below, the Hornby specimen is not pretty. Following our presentation of the fossil at SVPCA 2016, pterosaur guru David Unwin suggested we might have the ugliest pterosaur fossil on record (or at least tied the game). But while not well preserved, we do at least have several bones to play with: most of a humerus, three fused vertebrae (from the notarium, a set of fused shoulder vertebral elements), a few loose dorsal vertebrae and some other odds and ends that defy identification. This makes it the first set of associated bones of a small latest Cretaceous pterosaur, which is at least a step in the right direction for their paltry fossil record. For reasons discussed in the paper (concerning taphonomy, element size and likely identifications) we assume these remains represent one individual.
I don't want to rehash the full gory details of our study here - please read the paper for the technical aspects - but instead want to outline our main points. The first thing to clear is that we've been careful to rule out an avian ID for the specimen. The Northumberland Formation contains several bird fossils and the quality of the specimen means that many obvious pterosaur features are missing. The Royal British Columbia Museum was kind enough to ship the specimen all the way from Vancouver, Canada to Southampton, UK just so Liz and I make a thorough assessment on this issue. Happily, we found the specimen to be very pterosaur like in every aspect (even as fragments, pterosaur bones are quite distinctive) as well as differing from Mesozoic birds in several ways. It particularly contrasts in having a notarium, which seem absent from Mesozoic birds (note that we compared the notarium element compared carefully with Mesozoic bird synsacra to be sure of our identification), as well as having a pterosaur-like, rather than avian, proximal humerus morphology. But we're not bird workers so, to be extra sure, we showed the material to fossil bird experts in Canada and the UK (including people who've identified and published on the Northumberland Formation avians). No-one we spoke to suggested an avian ID and, moreover, we are aware that other people with expertise in both birds and pterosaurs (including our paper editor) have seen the material and prefer a pterosaur ID. Based on our research and the testimonials of others, we're as confident as we can be that the Hornby fragments represent a pterosaur, not a bird.
We've identified the Hornby specimen as an azhdarchoid, and noted several features indicative of, but not conclusive to, an azhdarchid ID. We suspect the specimen is an azhdarchid because of its provenance and its basic anatomical characteristics, but the specimen does not contain the right bits to confirm an azhdarchid identity. Nonetheless, narrowing the specimen down to Azhdarchoidea allows us to estimate its body proportions and confirm that the specimen was indeed a small animal when it died. We estimated its wingspan using two methods factoring both the humerus and vertebrae, and each pointed to a wingspan between 1.4 and 1.6 m. That puts our pterosaur at a comparable size to a good sized-seagull and, while these are respectably-sized modern birds, this is small for a latest Cretaceous pterosaur. Rather than poking giraffes in the face, our little chap would only just be beyond predation risk from an average housecat (below). The only contemporary pterosaur competing with the Hornby azhdarchoid for size is Piksi, a poorly known possible pterosaur from the western US. Our new study lists a number of reasons why the pterosaurian characterisation of Piksi is problematic however: in short, its morphology is all wrong for a flying reptile and we suspect a non-pterosaurian ID is more likely. The Hornby specimen is thus a contender for the smallest latest Cretaceous pterosaur currently known.
This million dollar question, of course, is whether the specimen is a small juvenile or a small adult. The former would be neat, but the latter is potentially significant. The findings of recent, detailed histological examinations of pterosaur fossils are permitting increasingly good understanding of their growth regimes (e.g. de Ricqles et al. 2000; Prondvai et al. 2012), so we made a section of the humerus to understand how old the Hornby animal was when it died. Our section showed a mix of bone textures, some indicating that the specimen was still growing, but other features (secondary osteons, an endosteal lamella, lines of arrested growth and a large structure forming on the internal bone surface) are indicative of relative maturity (de Ricqles et al. 2000; Prondvai et al. 2012). We found the endosteal lamella (a band of bone deposited around the internal bone cavity) of particular interest, as this seems to signify the end of internal bone expansion in azhdarchoids, and is thus a hallmark of near-mature animals (note that this is not true for all pterosaurs - see Prondvai et al. 2012). The fused dorsal vertebrae are a further marker of maturity, as pterosaurs do not develop these features until they're at least subadults. The exact timing of notarium formation seems to differ from taxon to taxon (e.g. Bennett 1993; Kellner 2015), but their development does not seem to start until these animals were near to full size, if not at full size already. Putting these and a few other observations together suggests that the Hornby pterosaur was a latest-stage juvenile or subadult: in other words, it looks like a genuinely small pterosaur, not just a juvenile one. We don't know how much larger it might have got before it reached full size, but its ontogenetic characteristics and what we know of pterosaur growth regimes suggests it was close to maximum size at time of death. Given its estimated 1.5 m wingspan, it had a good chance of remaining smaller than the next smallest, 2.5 m wingspan pterosaur currently known the Campanian or Maastrichtian (McGowen et al. 2002).
To my mind, one of the most significant things we do in the paper is discuss the 'face value' interpretations of Late Cretaceous pterosaur diversity: should we really be interpreting the lack of small pterosaur fossils as a genuine feature of their history when their fossil record is so patchy? We point out that some types of small pterosaurs - juveniles - had to exist in the Late Cretaceous, and yet their fossils are almost entirely unknown. We argue that this indicates a preservation bias against small bodied pterosaurs of any kind in the Campanian and Maastrichtian. Until we amass a good number of small juvenile pterosaur bones from this time without any small adults we cannot distinguish preservational interference from genuine biological signals. Perhaps the shift of pterosaurs from marine to non-marine habits through the Cretaceous (Butler et al. 2013) accounts for this lack of data. It's well known that terrestrial settings are less conducive to preserving relatively delicate fossils and small examples of even robust terrestrial animals like dinosaurs rarely fossilise in these deposits. We have to wonder what chance small pterosaur skeletons - which were strong in life, but fragile and weak once exposed to decay - have of making it into the fossil record in these settings. The fact the Hornby specimen is in such a sorry state perhaps reflects the rough time small pterosaur fossils experience under 'typical' fossilisation regimes, rather than the far gentler handling of animal remains evident at fossil Lagerstätten.
With all this said, the most important message of the paper has to be this: we need more data on small pterosaurs in the latest Cretaceous. The specimens we have are scrappy, hard to work with and offer limited scope for analysis. Thus, any small Late Cretaceous pterosaur material is significant, and whether they're lying unnoticed in museum collections or pulled straight out of the field, they are noteworthy specimens which need to be put on record. Curators and researchers, please keep your eyes peeled!
And that, in a nutshell, is our new paper: be sure to check it out if you want more details. You can also read Liz's take on the study over at The Conversation and other experts have been chiming in at news sites covering the story. With a bit of luck, this is not the only news you'll be hearing about Late Cretaceous pterosaurs from these quarters this year - more on these projects as they move along. All that's left to do is to thank Liz and Victoria for inviting me to collaborate with them on the new specimen - I learned a huge amount trying to get my head around this challenging material and its histology, and had a blast working with them.
pile of rubble specimen? What's the story with the landscape image and why is there an ammonite in it? How many iterations did we go through to get that composition? Head over to Patreon to get access to this and the rest of my exclusive content!
Secondly, Campanian and Maastrichtian pterosaurs are, without exception, pretty big animals. Many species from this time are renowned for their gigantic size: it's these stages which give us the famous 10 m wingspan, 250 kg colossi like Quetzalcoatlus, Arambourgiania and Hatzegopteryx, as well as a number of other giant azhdarchids which are too poorly known for generic titles. Coinciding with the evolution of the giants is a loss of small pterosaur taxa - those animals less than 2.5 m across the wings which are present, more-or-less, throughout the rest of pterosaur history. This shift in body size is sometimes interpreted as pterosaurs demonstrating 'Cope's Rule', the somewhat controversial proposal that species evolve towards large body size over time (Hone and Benton 2007; Benson et al. 2014). It's argued by some that competition from birds may be the driver behind this trend, as early avians fought small flying reptiles for ecological space and ultimately forced pterosaurs into larger sizes (e.g. Benson et al. 2014). Note that this concept is not without its detractors, including myself - I won't go into my reasons now but I plan to outline them here eventually.
Whether you agree with the bird-pterosaur competitive displacement hypothesis or not, we can't disagree that the end of the Cretaceous is almost entirely devoid of small pterosaur remains. Only a handful of specimens record small pterosaurs in the Campanian and Maastrichtian, and they're all tricky to work with. Aside from being highly fragmentary, some are controversially identified (such as Piksi barbarulna, an alleged small pterosaur from the Two Medicine Formation - see Agnolin and Varricho 2012 for the pro-pterosaur case) and others represent probable juvenile individuals (Godfrey and Currie 2005). Whatever it signifies, the lack of diminutive pterosaur specimens from the close of the Mesozoic is a real phenomenon of our fossil record, and any new specimen of a small, latest Cretaceous flying reptile has to be something to get excited about.
Enter: a new small, latest Cretaceous pterosaur specimen to get excited about
|Title slide of my SVPCA 2016 talk, discussing the findings of Martin-Silverstone et al. 2016, out today. If you don't get the reference, you clearly get out too much, have too many friends and aren't watching enough crap TV.
|RBCM.EH.2009.019.0001, a fragmentary azhdarchoid pterosaur from the Campanian Northumberland Formation, British Columbia. It's, er, not the prettiest pterosaur specimen you'll ever see. Combination of figures from Martin-Silverstone et al. 2016.
We've identified the Hornby specimen as an azhdarchoid, and noted several features indicative of, but not conclusive to, an azhdarchid ID. We suspect the specimen is an azhdarchid because of its provenance and its basic anatomical characteristics, but the specimen does not contain the right bits to confirm an azhdarchid identity. Nonetheless, narrowing the specimen down to Azhdarchoidea allows us to estimate its body proportions and confirm that the specimen was indeed a small animal when it died. We estimated its wingspan using two methods factoring both the humerus and vertebrae, and each pointed to a wingspan between 1.4 and 1.6 m. That puts our pterosaur at a comparable size to a good sized-seagull and, while these are respectably-sized modern birds, this is small for a latest Cretaceous pterosaur. Rather than poking giraffes in the face, our little chap would only just be beyond predation risk from an average housecat (below). The only contemporary pterosaur competing with the Hornby azhdarchoid for size is Piksi, a poorly known possible pterosaur from the western US. Our new study lists a number of reasons why the pterosaurian characterisation of Piksi is problematic however: in short, its morphology is all wrong for a flying reptile and we suspect a non-pterosaurian ID is more likely. The Hornby specimen is thus a contender for the smallest latest Cretaceous pterosaur currently known.
|A 1.5 m wingspan azhdarchoid next to one (SI) MrTiddlesmetre. From Martin-Silverstone et al. (2016).
|What's inside the RBCM.EH.2009.019.0001 humerus? A mix of things, but among them are features indicative of late-stage juvenility/subadulthood. Please see the paper for details of this figure. From Martin-Silverstone et al. 2016.
A small pterosaur amongst the pigeons
There's obviously a limit to what a single fragmentary specimen can tell you about the evolution of a group, but what the Hornby specimen means for pterosaur evolution is interesting and - if we've interpreted it correctly - potentially significant. Most obviously, it suggests that small pterosaurs may have been present in the Campanian stage of the Late Cretaceous after all, at least in one part of the world. Regular readers will be aware that there's growing evidence for Late Cretaceous pterosaur faunas being less uniform than previously realised (e.g. Vremir et al. 2013, 2015), and our new specimen plugs into this picture nicely: it increasingly seems that the end Cretaceous wasn't just a stage for large-to-giant long-necked azhdarchids. What's more, while the specimen only provides one data point against the idea that birds ousted small pterosaurs, the presence of at least two types of bird in the Northumberland Formation seems to indicate small pterosaurs and birds coexisted in at least this palaeoenvironment. We might see this as a continuation of the coexistence pterosaurs and birds demonstrate in Jurassic and Early Cretaceous localities: maybe pterosaurs and birds got along OK after all.
|...except when pterosaurs stole their eggs. Our PR art for the new paper, where a group of Hornby azhdarchoids perform guerrilla raids on shore-living Campanian bird nests. Take THAT, birds.
With all this said, the most important message of the paper has to be this: we need more data on small pterosaurs in the latest Cretaceous. The specimens we have are scrappy, hard to work with and offer limited scope for analysis. Thus, any small Late Cretaceous pterosaur material is significant, and whether they're lying unnoticed in museum collections or pulled straight out of the field, they are noteworthy specimens which need to be put on record. Curators and researchers, please keep your eyes peeled!
And that, in a nutshell, is our new paper: be sure to check it out if you want more details. You can also read Liz's take on the study over at The Conversation and other experts have been chiming in at news sites covering the story. With a bit of luck, this is not the only news you'll be hearing about Late Cretaceous pterosaurs from these quarters this year - more on these projects as they move along. All that's left to do is to thank Liz and Victoria for inviting me to collaborate with them on the new specimen - I learned a huge amount trying to get my head around this challenging material and its histology, and had a blast working with them.
This blogpost, paper and artwork are sponsored by PatreonRegular readers will know that this blog and its art are sponsored by a suite of awesome Patrons, but this post is proof that this support goes further than mere internet tomfoolery and contributes to papers and outreach, too. Supporting my blog from $1 a month not only helps keep this blog ticking over, but helps me contribute thoughts, words and illustrations to scientific research. In return you get access to bonus blog content: additional commentary, in-progress sneak-previews of paintings, high-resolution artwork, and even free prints. For this post, we'll be talking about the PR art I've done for this research: how was the azhdarchoid reconstructed from that
- Agnolin, F. L., & Varricchio, D. (2012). Systematic reinterpretation of Piksi barbarulna Varricchio, 2002 from the Two Medicine Formation (Upper Cretaceous) of Western USA (Montana) as a pterosaur rather than a bird. Geodiversitas, 34(4), 883-894.
- Bennett, S. C. (1993). The ontogeny of Pteranodon and other pterosaurs. Paleobiology, 19(01), 92-106.
- Benson, R. B., Frigot, R. A., Goswami, A., Andres, B., & Butler, R. J. (2014). Competition and constraint drove Cope's rule in the evolution of giant flying reptiles. Nature communications, 5, 3567.
- Butler, R. J., Benson, R. B., & Barrett, P. M. (2013). Pterosaur diversity: untangling the influence of sampling biases, Lagerstätten, and genuine biodiversity signals. Palaeogeography, Palaeoclimatology, Palaeoecology, 372, 78-87.
- Godfrey, S. J., & Currie, P. J. (2005). Pterosaurs. Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed, 292-311.
- Hone, D. W. E., & Benton, M. J. (2007). Cope's Rule in the Pterosauria, and differing perceptions of Cope's Rule at different taxonomic levels. Journal of Evolutionary Biology, 20(3), 1164-1170.
- Kellner, A. W. (2015). Comments on Triassic pterosaurs with discussion about ontogeny and description of new taxa. Anais da Academia Brasileira de Ciências, 87(2), 669-689.
- Martin-Silverstone, E., Witton, M. P., Arbour, V. M, & Currie, P. J. (2016). A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants. Royal Society Open Access, 3, 160333.
- McGowen, M. R., Padian, K., De Sosa, M. A., & Harmon, R. J. (2002). Description of Montanazhdarcho minor, an azhdarchid pterosaur from the Two Medicine Formation (Campanian) of Montana. PaleoBios, 22(1), 1-9.
- Prondvai, E., Stein, K., Ősi, A., & Sander, M. P. (2012). Life history of Rhamphorhynchus inferred from bone histology and the diversity of pterosaurian growth strategies. PLoS One, 7(2), e31392.
- Vremir, M., Kellner, A. W., Naish, D., & Dyke, G. J. (2013). A new azhdarchid pterosaur from the Late Cretaceous of the Transylvanian Basin, Romania: implications for azhdarchid diversity and distribution. PLoS One, 8(1), e54268.
- Vremir, M., Witton, M., Naish, D., Dyke, G., Brusatte, S. L., Norell, M., & Totoianu, R. (2015). A Medium-Sized Robust-Necked Azhdarchid Pterosaur (Pterodactyloidea: Azhdarchidae) from the Maastrichtian of Pui (Haţ eg Basin, Transylvania, Romania). American Museum Novitates, (3827), 1-16.
Friday, 12 August 2016
Trunk or no trunk, small or giant ears, long or short neck... what did the giant rhinocerotoid Paraceratherium really look like?
|Giant, Oligocene rhinocerotoids Paraceratherium transouralicum engage in some early morning flirting. Because, in rhino speak, playing hard to get involves shoulder barges and head-butts.
The obligatory note on nomenclatureIt almost seems tradition that any article or paper on indricotherines requires an aside on their confused taxonomy. As has been the case for decades now, the taxonomy and systematic nomenclature of these giant rhinocerotoids are a matter of ongoing discussion. It is widely appreciated that several giant indricotherine species from roughly contemporaneous Oligocene Asian sediments can be identified, but how many species they represent, and how they are related to each other, is not clear. At least seven generic titles and many more species names have been given to the largest of these animals over the years (Indricotherium and Baluchitherium are perhaps the most famous generic labels), but some authors (e.g. Lucas and Sobus 1989, Prothero 2013) tidy all or most of these taxa into three species of the oldest established genus, Paraceratherium. Arguments persist, however, that at least one other, perhaps slightly smaller genus existed, Dzungariotherium (Qiu and Wang 2007). Geologically older indricotherine genera such as the Eocene Urtinotherium are also wrapped into these discussions as remains attributed to the Oligocene genera are sometimes argued as having greater affinity to these older taxa (Prothero 2013).
This confusion is sometimes framed as a 'lumper/splitter' philosophical distinction, but it does not help that the fossil record of these giant rhinocerotoids is far from exemplar: giant indricotherine specimens can be fragmentary, of starkly contrasting size with one another, and many suffer from distortion. The fact that 20th century indricotherine science developed with Asian and American teams working largely in isolation, with limited access to certain specimens and literature, has also contributed to the confused history of this group. Those interested in the history of indricothere taxonomy should check out Prothero (2013) for an overview. For now, it will serve us to simply state that the best known, biggest and most famous of these animals currently resides as the taxonomic address of Paraceratherium transouralicum. This is the species most of us think of as 'the' giant indriotherine as well as the taxon that has carried both the Indricotherium and Baluchitherium label at one time or another. It's also the focus of most artwork of giant rhinoceratoids, and thus forms our primary interest here.
Giant rhino, bulky giraffe or giant workhorse?One reason we see such variation in indricotherine appearance is that researchers have produced vastly different interpretations of its anatomy in the last 100 years. But unlike, say, dinosaurs, where older reconstructions have been (for the most part) abandoned in favour of newer, more accurate interpretations, educators and researchers continue to publish skeletal reconstructions published in the 20s and 30s despite our improved knowledge of indricotherine anatomy, documented criticisms of these older works, and the availability of more modern, theoretically better-informed reconstructions.
Many readers may be aware that the first reconstruction of Paraceratherium, published by Osborn (1923a), showed a form not too far off a giant rhinoceros - a heavyset, short-necked animal with a deep torso and short legs. Osborn published a revised version almost immediately after his first effort, which had a much longer neck and longer legs thanks to data provided by additional fossil material (Osborn 1923b). A shorter-necked version was then produced by Granger and Gregory (1935, 1936), who scaled the remains of numerous, differently-sized individuals from a range of collections to create their robust, gigantic take on indricotherine anatomy. Although this reconstruction has been quite influential, Fortelius and Kappelman (1993) have been critical of the scaling methods used by Granger and Gregory, calling their interpretation 'a highly speculative creation indeed'.
|Paraceratherium has been variably reconstructed over the years, with particular disagreement over how long the neck was compared to the body. So far as I can tell, a consensus on the life appearance of these animals has yet to be reached.
And so we turn to another indricotherine skeletal reconstruction, produced by Paul (1997). This restoration incorporated data from the same specimens used in the efforts above and came out somewhat 'averaged' between the more heavyset restorations of the early 20th century and the gracile interpretation of the 1950s. It looks, in overall form, more like a giant workhorse than it does a giant rhino or bulky giraffe. Paul (1997) provides some discussion of the reconstruction process - this is worth a read if you're interested in the life appearance of Paraceratherium and its relatives. Paul's interpretation has, to my knowledge, escaped criticism to date and, to the contrary, Larramendi (2016) described this reconstruction as 'accurate', although did not elaborate on why it should be considered superior to older efforts.
The million dollar question here is obvious: which one of these different takes on Paraceratherium is 'right'? To be honest, I'm not sure. The situation is compounded by the fact that a lot of indricotherine literature is obscure, that the specimens fragmentary and that many of them await description. I was hoping that Donald Prothero's recent (2013) book Rhinoceros Giants, which is solely dedicated to Paraceratherium, would provide some insight on this matter, but it's not a great help here - it provides no real evaluation on the different reconstructions and does not even mention Paul's 1997 effort. My work above is primarily based on Paul's (1997) skeletal but this is largely because of principle rather than real insight. Paul's work is the most modern and, of course, he's made a career out of reliably reconstructing extinct animals. The brief endorsement from Larramendi (2016) helps here too, of course, but a longer discussion of the relative merits and detriments of each interpretation would be useful. Opinions from others with more insight into this matter are welcome in the comments below.
A tapir-like proboscis... on a rhino?Turning our attention to the face, did Paraceratherium and its relatives have relatively short-lipped faces like those of rhinos, or long, mobile proboscides like their more distant relatives, the tapirs? Despite mammal lips and nasal tissues being highly fleshly and thus only rarely entering the fossil record, this is a surprisingly easy question to answer. Whether rhino, tapir or anything else, a suite of osteological characters seem to correlate well with the presence of proboscides. Briefly summarised, these are: narrow snouts; retraction of the nasal openings towards the orbits; the presence of large muscle scars, bony knobs and other muscle attachment markers around the nasal opening (particularly in the dorsal region); retraction of the nasal bone (the 'roof' of of the nasal opening); deepening of the premaxillary bone (the bone making the jaw tip); anterior migration of the orbit; a large intraorbital canal (a foramen situated in the cheek region, just in front of the eye - it houses the nerves and blood vessels for our anterior face muscles); and strengthening of the posterior skull regions related to supporting the weight of the head on the neck (Wall 1980). Note that the criteria for elephant-like trunks are similar, but slightly different.
|Paraceratherium transouralicum (formerly Baluchitherium grangeri) skull in dorsal, lateral and ventral views. Note features around the skull anterior linked to proboscis development (see text). From Osborn (1923b).
And big, elephant-like ears, right?Finally, let's tackle the component that everyone now mentions about indricotheres since seeing the Carl Buell's cover art for Donald Prothero's Rhinoceros Giants:
|Indiana University Press.
"...indricotheres were larger in body mass than any living elephant and almost certainly had problems regulating their body heat at such large size. Elephants must do all they can to increase the surface area of their bodies to release as much excess heat as possible, which is why they have huge fan-like ears full of blood vessels that are essentially giant radiators. Given the huge size of indricotheres, it seems likely that they too should have had elephant-like ears, or at least very large ears of some shape, much larger than they are usually drawn."
Prothero, 2013, p. 90.
The text continues to suggest that this appearance is not without anatomical support, the prominence of the mastoid and paroccipital processes (projections of bone situated behind the ear opening, adjacent to the posterior surface of the skull) being similar to the condition in certain elephants and mastodonts, and therefore indicative of large, flappy ears (Prothero 2013).
I have mixed feelings about this reconstruction. I like it for two reasons. The first is that it's nice to see indricotheres being distanced from their depiction as giant, long-necked rhinoceroses - again, it's not unreasonable to think they may have looked quite different in to modern rhinocerotids in many aspects. I also like these ears for being an All Yesterdays-style speculation on soft-tissue adaptations in extinct species. If we can use this as an excuse to give fat stores to desert sauropods or fuzzy hides to Arctic ceratopsids, then we can give large ears to giant rhinoceratoids.
On the other hand, I'm not convinced that they're as likely as Rhinoceros Giants suggests. It's clear from our modern fauna that ear size does not correlate with body mass in terrestrial mammals. By this logic many rhinos and giraffes should have proportionally large ears too, which they evidently do not. We also have to consider that even larger animals than indricotheres, dinosaurs, almost certainly got by without giant ears to help lose heat. And yes, while dinosaurs may have used different metabolic strategies to mammals, one inescapable consequence of giant size is a constant high body temperature. At least some investigations into the proportions of large dinosaurs suggest that development of their features - such as sauropod necks - were not driven by thermoregulatory pressures (Henderson 2013).
We should also consider the unusual nature of elephant thermoregulation: they are not typical mammals when it comes to controlling body heat. For one, they're atypically compact compared to other large mammals because they have extremely short necks, giant, round heads, and big, rotund torsos. This is a suboptimal bauplan for thermoregulation because it minimises surface area with respect to volume, and thus reduces the available area for elephants to dump excess heat. Moreover, unlike most mammals, they lack sweat glands (Wright and Luck 1984), do not pant, and they live in climates which are so warm that for much of the day they cannot shed heat through simple convection, big ears or not (Weissenböck et al. 2012). Elephants can, of course, regulate their temperature, but they need to employ different strategies to the rest of us mammals. These include maintaining moist skin with mud bathing and trunk spraying (Wright and Luck 1984), maintaining a sparse set of body hair to aid thermal escape (Myhrvold et al. 2012), using heterothermy (Weissenböck et al. 2012), the development of 'thermal windows' in their skin (Weissenböck et al. 2010), having loose and highly wrinkled skin to boost surface area and - of course - fanning their blood-vessel rich ears to help lose heat, when ambient temperatures are low enough for this to make a difference.
So...Putting all this together, it seems that there might be less need for uncertainty about indricothere appearance than our various artworks suggest. We should be saying 'yes' to some sort of proboscis, and 'probably not' to big ears (or, at least, 'there's no reason for them'). The elephant (or, giant rhino, if you prefer) in the room is the proportion issue, and it would be good to see folks who really know rhinocerotoid anatomy pore over those various reconstructions to ascertain which (if any) are the best representation of indricotherine form.
Next time: either the Next Big (but also kinda small) Thing in pterosaur research, or another trip to the Triassic.
Big rhinos need big support - thank goodness for PatreonThe paintings and words featured here are sponsored by another group of (metaphorically) giant mammals, my Patreon backers. Supporting my blog from $1 a month helps me produce researched and detailed articles with paintings to accompany them, and in return you get access to bonus blog content: additional commentary, in-progress sneak-previews of paintings, high-resolution artwork, and even free prints. For this post, we'll be taking a further look at the anatomy of the Paracertherium in my painting, above. Why do they have little manes and stripy faces? Are those child rhinos at the back a bit fuzzy? And why do the main animals look like they're fighting? Head over, and sign up to Patreon to get access to this and the rest of my exclusive content!
- Endo, H., Kobayashi, H., Koyabu, D., Hayashida, A., Jogahara, T., Taru, H., Oishi, M., Itou, T., Koie, H. & Sakai, T. (2009). The morphological basis of the armor-like folded skin of the greater Indian rhinoceros as a thermoregulator. Mammal Study, 34(4), 195-200.
- Fortelius, M., Kappelman, J., 1993. The largest land mammal ever imagined. Zoological Journal of the Linnean Society, 108, 85-101.
- Goldfinger, E. (2004). Animal Anatomy for Artists: The Elements of Form. Oxford University Press.
- Granger, W., & Gregory, W. K. (1935). A revised restoration of the skeleton of Baluchitherium, gigantic fossil rhinoceros of Central Asia. American Museum of Natural History, 787, 1-3.
- Granger, W., & Gregory, W. K. (1936). Further notes on the gigantic extinct rhinoceros, Baluchitherium, from the Oligocene of Mongolia. American Museum of Natural History, 72, 1-73.
- Gromova, V. (1959). Giant rhinoceroses. Trudy Paleontologiskei Institut Akademie Nauk, 71, 1-164.
- Henderson, D. M. (2013). Sauropod necks: are they really for heat loss?. PloS one, 8(10), e77108.
- Hiley, P. G. (1977). The thermoregulatory response of the rhinoceros (Diceros bicornis and Ceratotherium simum) and the zebra (Equus burchelli) to diurnal temperature change. African Journal of Ecology, 15, 337-337.
- Larramendi, A. (2016). Shoulder height, body mass and shape of proboscideans. Acta Palaeontologica Polonica, 61, 537-574
- Lucas, S. G., & Sobus, J. C. (1989). The systematics of indricotheres. In: Prothero, D. R., and R. M. Schoch (eds.) The Evolution of Perissodactyls. Oxford University Press, New York, 358-378.
- Myhrvold, C. L., Stone, H. A., & Bou-Zeid, E. (2012). What is the use of elephant hair?. PloS one, 7(10), e47018.
- Osborn, H. F. (1923). The extinct giant rhinoceros Baluchitherium of Western and Central Asia. Natural History, 23, 208–228.
- Osborn, H. F., & Berkey, C. P. (1923b). Baluchitherium grangeri, a giant hornless rhinoceros from Mongolia. American Museum of Natural History, 78, 1-15.
- Qiu, Z. X., Wang, B. Y., 2007. Paracerathere fossils of China. Palaeontologia Sinica, C29, 1-396
- Paul, G. S. (1997). Dinosaur models: the good, the bad, and using them to estimate the mass of dinosaurs. DinoFest International Proceedings. Philadelphia: The Academy of Natural Sciences, 129-154.
- Prothero, D. R. (2013). Rhinoceros Giants: The Paleobiology of Indricotheres. Indiana University Press.
- Wall, W. P. (1980). Cranial evidence for a proboscis in Cadurcodon and a review of snout structure in the family Amynodontidae (Perissodactyla, Rhinocerotoidea). Journal of Paleontology, 54, 968-977.
- Weissenböck, N. M., Weiss, C. M., Schwammer, H. M., & Kratochvil, H. (2010). Thermal windows on the body surface of African elephants (Loxodonta africana) studied by infrared thermography. Journal of Thermal Biology, 35, 182-188.
- Weissenböck, N. M., Arnold, W., & Ruf, T. (2012). Taking the heat: thermoregulation in Asian elephants under different climatic conditions. Journal of Comparative Physiology B, 182(2), 311-319.
- Wright, P. G., & Luck, C. P. (1984). Do elephants need to sweat?. South African Journal of Zoology, 19(4), 270-274.
Subscribe to: Posts (Atom)

subset: commoncrawl


text:
Fenix HL60R
Featuring a micro-USB port for go-anywhere charging, the Fenix HL60R Headlamp delivers a maximum output of 950 lumens, beam distance of up to 381ft and a runtime of up to 100 hours from just one rechargeable18650 Li-ion battery. This feature rich headlamp is equipped with neutral white LED for better color rendering, a side switch to activate the five brightness levels and the red night vision mode. The HL60R is an all-season headlamp designed with an all-metal housing and waterproof up to 2m underwater.
- Utilizes Cree XM-L2 T6 Neutral White LED with a lifespan of 50,000 hours
- Powered by one 18650 Li-ion battery or two CR123A batteries
- 87mm Length x 46mm Width x 51mm Height
- 121-gram weight (excluding battery)
- Digitally regulated output maintains constant brightness
- Reverse polarity protection, to protect from improper battery installation
- Side switch for fast and simple operation
- Charging cable features Micro USB port, directly charges 18650 rechargeable Li-ion battery
- Characteristic red light
- Made of durable high-grade aluminium
- Premium Type III hard-anodized anti-abrasive finish
- Toughened ultra-clear glass lens with anti-reflective coating
- Length: 3.4" (87mm)
- Width: 1.8" (46mm)
- Height: 2.0" (51mm)
- Weight: 4.3 oz. (121g) excluding batteries
- One rechargeable 18650 Li-ion battery
With Fenix HL60R you can enjoy your activities without complications. If you like the brand Fenix and their running & triathlon products, visit the categories of the running & triathlon products that you are looking for and place your order as soon as possible and receive it in a few days. Our aim at runnerinn is to make high-quality products accessible to all with an efficient worldwide delivery service.
View more related products to:Fenix - Lighting - Torches
Customers who viewed Fenix HL60R, also viewed:


text:
Helmet Camcorder
HD Action Camera
Here at Helmet camcorder we pride ourselves on Quality. We have found a supplier which meets those qualifications of quality, performance and customer service
About SportzTek
SportZTek, Was formed out of a necessity for a high quality affordable HD Action Video camcorder the owner has a love for anything outdoors. They are based in Bluffdale UT which is in the Intermountain west.
The Intermountain West provides a vast array of outdoor sports with great opportunities to CAPTURING any and all experiences by recording them in high definition, and being able to relive those experiences
Having the right device to CAPTURE and RECORD these moments doesn't have to be expensive. SportZTek went direct to the factory to have a HD Action Camera for everyone to be able to afford and to RELIVE their most carefree and exciting moments in life.
Their mantra is CAPTURE. RECORD. RELIVE.……with NO REGRETS!
Website . http://www.sportzcam.com/
Basic Package – Camera and Accessories
Deluxe Package – Camera and Accessories plus a spare battery
Premier Package – Camera and Accessories, spare battery plus a 32 GB SD card


text:
Released: 15.11.12
The Tavistock Trust Award for Aphasia was recently given to Erin Jarvis ,Speech and Language Therapy (SLT) Year 2. The award was given for her outstanding case study, in Year 1 of an individual suffering from aphasia.
The prize of £300 is awarded following a nomination process that takes place at the exam board. The Tavistock Trust was set up in memory of Robin Tavistock, Duke of Bedford, who suffered aphasia following a stroke, and aims to promote excellence in the field of aphasiology.
Maggie Cooper, Head of Department of Applied Language Sciences said "On behalf of all the SLT Department I'd like to congratulate Erin on her worthy award. Erin produced an outstanding study of an individual with aphasia following her placement experience, and her nomination was met with unanimous support. This acheivement is particularly noteworthy as Erin is the first Year 1 student from UCP Marjon to be nominated for the Tavistock Trust Award."
Back to Marjon News


text: How a Chinese Company 3D-Printed Ten Houses In a Single DayKelsey Campbell-Dollaghan4/03/14 2:00pm667EditPromoteDismissUndismissHideGo to permalinkThis month, architects in Amsterdam started work on the world's first completely 3D-printed house. It'll take three years and quite a bit of money to finish. Meanwhile, in Shanghai, a company claims to have printed ten houses with inexpensive industrial scraps in less than a day. What's the difference?


text:
Stock Market Analysis Video 12/9/2011
In this week's Stock Market Analysis Video, Cabot China & Emerging Markets Report Editor Paul Goodwin sees the market's range of motion tightening up—with swings much narrower than they had been. This is a good sign, says Paul, as continuing tightening could lead to a new rally. But right now, there's still lots of resistance, so Paul's advice is to remain heavily in cash until the market direction becomes clearer. He names four stocks that he's keeping a close eye on: Sohu.com (SOHU), Colfax Corp. (CFX), FMC Technologies (FTI) and Fortinet (FTNT).~~~
Think it's too late to make astounding profits in China?
Think again!
Here's why the second half of 2011 will be a great year for our favorite Chinese stocks.
Dear Investor,
I've seen the future, and its name is China.
Hello. My name is Paul Goodwin. I'm editor of Cabot China & Emerging Markets Report. While the rest of the global economy fell off a cliff during the Great Recession of 2008-2009, China's economy continued to grow by roughly 9% a year.Now that the brutal global recession is finally behind us, China is ready to surge anew. With an unemployment rate of only 4% (compared to nearly 9% in the U.S.), its factories are humming and its increasingly affluent consumers are itching to buy.
As an investor, it's crucial that you have at least some exposure to China, which represents more than 10% of the world's Gross Domestic Product (GDP), but you have to know how to invest there.
Only about 32% of the huge Chinese population has access to the Internet, compared to 77% of Americans.
But it's not just technology. Name virtually any business sector and China plays a crucial role. Sure, China has been on a tear the last few years. But does it have the wherewithal to sustain the same breakneck pace? You bet it does.
According to the International Monetary Fund, over 95 countries are richer than China. Japan's per capita income is $10,085. China's per capita income is about $1,000. Impoverished nations like Libya, Lebanon, Romania, Gabon, Botswana, Azerbaijan, Namibia, Tunisia and Albania have higher per capita incomes than China. China's GDP per capita is only one-eighth that of the United States.
And here's the kicker: China has almost no debt per GDP compared to the West.
The upshot? China still has plenty of room for growth. What's more, the world economy is finally recovering. For investors, that means the biggest profits in China still lie ahead.
Does China face problems? Sure—problems that other countries would envy. China's savings rate is over 35%, while in America it's 2%. The goal of China's leaders right now is to reduce excess savings, by getting their people to spend more. And that says loud and clear that China will rack up sustained, rapid growth this year—and for decades to come.
According to the World Bank, about 20 million people in China (roughly the population of Australia) turn 18 every year.
Millions of Chinese workers are earning higher wages, joining the middle class and flexing their new consumer spending power by buying homes, automobiles, computers, and cell phones.
And they're traveling more, which explains why China now has more than 40 new airports on the drawing board.
China's continuing rural-to-urban shift is one of the largest human migrations in history. City populations and boundaries will expand by 20 million in 2011.
It should come as no surprise, then, that China's infrastructure development is expanding like gangbusters—and it will continue to do so, for the next few decades. China is building new highways at a pace unseen since America's infrastructure binge in the 1950s and '60s.
In the next 20 years, China plans to build about 50,000 miles of major new road, roughly the equivalent of the U.S. interstate system. The World Bank projects that China's fixed assets—ports, bridges, and roads—will double every two and a half years for the next two decades.
Add up these figures and you have the formula for massive, sustained growth from now to 2025—and beyond.
I'm offering you the opportunity that thousands of investors have already accepted―a risk-free 60-day trial to my newsletter, to discover what it's like to ride the rocket in Chinese mega-growth stocks.
Don't miss this chance to receive 60 days—four bi-weekly issues—of Cabot China & Emerging Markets Report without risk.
As soon as I receive your acceptance, you'll have nearly instantaneous access to our current recommendations.
Best wishes with all of your investments,
Paul Goodwin
Editor, Cabot China & Emerging Markets Report
P.S. When you order now you've everything to gain and nothing to lose with our double money-back guarantee! For the first 60 days, you'll receive Cabot China & Emerging Markets Report entirely at my risk. If you aren't impressed after 60 days, simply let me know and I'll refund every penny of your subscription. You risk nothing. And you are always free to cancel your subscription for any reason after the 60-day period for a pro-rated refund, no questions asked. Learn more now!
--- TRANSCRIPT Stock Market Video 12/09/2011 ---
[ Music ]
>> Hi, I'm Paul Goodwin the editor of the Cabot China and Emerging Markets Report and this is your Cabot weekly video review. It hasn't--it hasn't been a lot of great news this week.
We take a look at the halter USX China index here which is what we use to do the market timing for the report. You can see that probably the best news is that the range of motion indexes has tightened up a little bit. I find this kind of a calming sort of thing, not getting quite as big swings as we've had before. I think probably there's a little bit of news fatigue here going on. And what I would look for is continued tightening in this index which often eventually lead to--to some pretty good rallies.
If it works, the SNP 500, you can see that a wonderful heartening last week, little rally that we got which is now just, you know, top gathered about twelve sixteen and had another bad day today. There's a lot of resistance here and it's just not--it's just not doing as much good right now.
So, although we don't think things are dire and we also think that it's still a good time to be in cash and probably a good time to keep all of your growth stocks on a short leash.
If you look at--if we look at Wanda [phonetic] for a few of the stocks that we're kinda keeping an eye on, here's one of Sohu.com (SOHU) which is a computer--an online portal in China and, you know, looking at the data on Sohu and you think why is this company that's been showing, you know, steady revenue growth and earnings growth trading it just a PE of just 12 and why has it been going through this kind of negative time that it's going through right now. And the answer is probably that people are a little distrustful of China and they distrust the market in general.
Also like Colfax Corp. (CFX). This is a great looking chart Colfax does pumps including the pumps that are used in the Chinese three gorgeous dam. It's kind of an infrastructure play but look at this, you know, wonderful decline and then, you know, jumps up and then takes off of what looks like a more sustainable thing with sustainable up trend with some excellent volume clues here.
Also we're looking at FMC Technologies (FTI) an offshore oil infrastructure company, builds a nice quiet descending base here and then takes off again with a couple of good weeks of volume clues here.
And finally this is a story that we've liked for years Fortinet (FTNT) and this is a kind of story where you wanna watch the chart very closely because after this breakdown then the stock decline at a more orderly way has, has come back but now looks like it's finding a little resistance right in this area. We really like this computer security story but probably also a good idea to wait until it breaks out above that resistance.
So, I'm--I'm optimistic in a modified sort of way but it's certainly not time to start putting too much money to work. So, that's about it for this week and we'll see you again next week.
If you need any other information about Cabot newsletters, you can always find us at Cabot.net, thanks.
[ Music ]
Paul Goodwin
Emerging Markets Specialist, Analyst and Editor of Cabot China & Emerging Markets Report
A researcher and writer for over 30 years, Paul Goodwin has been a member of the Cabot investment team and editor of Cabot China & Emerging Markets Report since 2005. Under Paul's stewardship, Hulbert Financial Digest rated Cabot China & Emerging Markets Report the #1-rated newsletter of 2006 with a 78.6% gain for the year, the number-one-rated newsletter of 2007 with a 74.1% return. Cabot China & Emerging Markets Report was also named 2007 Investment Letter of the Year by Peter Brimelow of MarketWatch


text:
You missed it This great deal for Delgado Boxing is over. But don't despair, we've got more great deals every day.
Related Deals That You May Like
MetaBody Yoga and Fitness
30 Class Pass
Cheer & Dance Atlanta JayHawks
1 Month of Weekly Tumbling Classes
Amoora Dance & Fitness Center
Silk Aerial Classes
About Mind and Body
10 Fitness Classes or Month of Unlimited Classes
Delgado Boxing
Enjoy the Combined Benefits of Boxing and Kickboxing in Ten Group Fitness Classes
100% recommendedin LivingSocial customer ratings
At this Buckhead facility, pro boxer Paul Delgado heads a certified staff that has more than 65 years of combined boxing experience. Let them help you build muscle and achieve a kickin' new body with this deal:
• $49 ($150 value) for ten group classes that blend kickboxing and boxing
• $99 ($250 value) for five 45-minute private boxing fusion classes
• Schedules intense one-hour group workouts Monday to Saturday
"Don't be intimidated if you don't know how to box; everyone that works out, and especially the trainers, are very supportive and helpful and will work with you until you do!" - Happy Client
PAID VALUE EXPIRES ON October 24, 2021
PROMOTIONAL VALUE EXPIRES ON September 22, 2013