New data on the systematics and interrelationships of sawfishes   (Elasmobranchii, Batoidea, Pristiformes)
  New characters based on the arrangement and morphology of dermal denticles show that sawfishes can be divided into two distinctive groups. The first group, comprising the knifetooth sawfish Anoxypristis cuspidata, is characterized by tricuspid denticles variably located on both dorsal and ventral parts of the body. The second group is represented by species of the genus Pristis, showing an uniform and homogenous dermal covering of monocuspidate denticles on both dorsal and ventral sides of the body and within the buccopharyngeal cavity. Pristis is further divided into two subgroups: the first comprises species with denticles lacking any keels and furrows (the smalltooth sawfish Pristis pectinata, the green sawfish Pristis zijsron and the dwarf sawfish Pristis clavata); the second comprises species with denticles presenting keels and furrows well differentiated on their anterior part (the common sawfish Pristis pristis, the largetooth sawfish Pristis perotteti and the greattooth sawfish Pristis microdon). This investigation of the dermal covering provides results which agree with studies that separate the same two species groups of Pristis on the basis of other morphological data. 
Pascal Deynat (DMPA)