{'fraction_non_alphanumeric': 0.039270858820650845, 'fraction_numerical': 0.033643259114264745, 'mean_word_length': 4.814366998577525, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
New Report on Two Species of the Genus Nipponomysis (Crustacea: Mysida: Mysidae) from Korean Waters

alcohol and illustrations prepared using a drawing tube on a com-pound microscope equipped with differential interference contrast Body length was measured from the tip of the rostrum to the distal ABSTRACT Two species of mysid, Nipponomysis fusca (Ii, 1936) and N. tenuiculus (Ii, 1940), are newly recorded in Korean fauna. These two species were collected using a light or a bait trap from all coasts of the Korean peninsula. The genus Nipponomysis can be distinguished from allied genus by the following morphological characteristics: third to eighth thoracic endopods with carpopropodus divided into five to six subsegments compared to three subsegments, and anterior four pairs of pleopod in female subequal in length and fifth pair elongated. Nipponomysis fusca is characterized by its acute rostral plate and armature of telson, and N. tenuiculus differs from other species by the number of spine in ventral statocyst region and the shape of the fourth pleopod in male. Herein, we present detailed descriptions of two species from Korean waters with illustrations of morphology. In addition, an identification key to the Korean species of the genus is provided.


INTRODUCTION
The genus Proneomysis was erected by Tattersall (1933) based on the type species, Proneomysis wailesi from Canadian Pacific coast. Since then, 14 species regarded as being from the genus have been reported from Asian Pacific coasts: 12 from Japan (Ii, 1936(Ii, , 1940(Ii, , 1964a(Ii, , 1964bMurano, 1977), one from Indonesian water (Ii, 1964b), and one from China (Wang, 1981). Continuous research by Holmquist (1982) suggested that some characteristics of P. wailesi differ between the specimens from Alaskan and Canadian coasts and samples from Asian water. At that time, the new genus Nipponomysis was proposed by him without a close examination. Thereafter, Takahashi and Murano (1986) agreed and concluded that all Asian species were not included in the genus Proneomysis, but as members of the new genus Nipponomysis on the basis of the type species, Proneomysis fusca (Ii, 1936). The genus Nipponomysis Takahashi & Murano, 1986 is clearly distinguished from the genus Proneomysis by the combination of the following characters: 1) third to eighth thoracic endopods with carpopropodus divided into five to six subsegments compared to three subsegments and 2) in female, anterior four pairs of pleopod subequal in length and fifth pair elongated, instead of gradually increasing in length from the first to the fifth pair. Jo and Jeon (2007) firstly reported three species belonging to the genus: N. lingvura Murano, 1977, N. ornata (Ii, 1964), and N. imparis Takahashi & Murano, 1986. Afterwards, Kim et al. (2012 reported one species, N. calcarata Takahashi & Murano, 1986. During a comprehensive taxonomic study of mysid assemblages of Korea, N. fusca (Ii, 1936) and N. tenuiculus (Ii, 1940) were newly discovered. Here we describe and illustrate these two species of Nipponomysis from Korean waters.

MATERIALS AND METHODS
All specimens were collected with a light and bait trap equipment. The specimens were preserved in 70% ethyl alcohol and illustrations prepared using a drawing tube on a compound microscope equipped with differential interference contrast (Model BX-60; Olympus, Tokyo, Japan). Body length was measured from the tip of the rostrum to the distal apex of the telson excluding the spine. The simple setae and plumage of the plumose setae on the margin of antennules, antennae, mouthparts, and uropods are omitted from the figures. Terminology for the dissection and measurement is adopted from Tattersall and Tattersall (1951). All specimens have been deposited in the Marine Arthropod Depository Bank of Korea (MADBK), Seoul National University.  Ii, 1936: 605, figs. 67-79;1964b: 531, fig. 139; Mauchline and Murano, 1977: 72. Nipponomysis fusca Takahashi and Murano, 1986: 133, 116, fig. 15;Müller, 1993 Fig. 2A) with anterior margin produced into triangular rostral plate with pointed tip, reaching middle of first segment of antennular peduncle; posterior margin emarginated, antero-lateral corners rounded. Eye ( Fig.  2A) normal; cornea reniform in dorsal view, occupying 1/2 of whole eye; eyestalk without denticles. Antennal scale (Fig. 2B) lanceolate with round apex, about 4 times as long as broad; distal suture occupying about 1/18 of whole length of antennal scale; outer margin straight, inner margin concave, entire margin with setose. Antennal peduncle 3-segmented; second segment longest, 2.5 times as long as first; third segment 1.5 times as long as first one.

SYSTEMATIC ACCOUNTS
Antennular peduncle (Fig. 2C) 3-segmented; first segment longest, 2 times as long as second one and bearing three plumose setae; second segment shortest, about 1/2 of third one.
Endopod of first and second thoracopods (Fig. 2G, I) shown no marked difference from those in other species of genus.
Anim. Syst. Evol. Divers. 31(1), 15-21 Telson (Fig. 3C) linguiform, about 1.5 times as long as broad; proximal half of lateral margin bearing 3-5 spines and remaining margin armed with series of spines which smaller 1-4 spines grouped between larger spines, larger spines increasing in length); apex truncated, armed with 2 pairs of spines, outer spines robust, 3 times as long as inner ones. Distribution. Korea (East, South, and Yellow Sea), Japan. Remarks. The specimens collected differ from those of other previous studies (Ii, 1936(Ii, , 1964bTakahashi and Murano, 1986). In the present study, the female rostrum of Korean specimens only extended to the middle of the first segment of the antennular peduncle. However, the original description of Ii (1936) noted that the rostrum extended to the distal end of the first segment of the antennular peduncle. Other differences were also observed by the following characters: 1) in our specimens, the ratio of whole length to proximal width of the antennal scale was 4 instead of 5 to 6 in previous records; 2) the ratio of the distal suture of antennal scale in the present specimens was 1/18 to 1/16, compared to 1/16 to 1/6 in previous studies.
Endopod of first, second thoracopods (Fig. 4B, J), and exopod of third to eighth thoracopods (Fig. 4I) shown no marked difference from those in other species.
Telson (Fig. 4L) narrowly long triangular, about 2 times as long as broad; proximal 1/3 of lateral margin bearing 8-9 spines and remaining margin armed with numerous series of spines which smaller 1-7 spines grouped between larger spines, increasing in length toward apex; apex truncated and armed with 2 pairs of spines, outer spines about 2 times as long as inner ones. Distribution. Korea (South Sea), Japan. Remarks. This specimen coincides with descriptions given by Ii (1940Ii ( , 1964b and Takahashi and Murano (1986) in general, except for following characters: 1) Ii (1940Ii ( , 1964b noted that the ventral inner margin of statocyst with 24 blunt spines compared to only 14 spines in the present specimen. Also, Takahashi and Murano (1986) recorded 21 spines by only showing the figures without descriptions. Secondly, Ii (1940Ii ( , 1964b described that the first and second segments of the exopod in male fourth pleopod are terminated by plumose setae on both inner and outer distal ends. On the other hand, presently there were no setae evident, which was badly damaged; 3) the entire whole length of the telson was 3 times as long as basal broaden part in the description of Ii (1940Ii ( , 1964b, but 2 times as long as broad in the present specimen. Even with these minor differences, this specimen is identified as Nipponomysis tenuiculus by virtue of the armature of the telson, especially the arrangement of the group of spines. This species has hitherto been described from Japan and has been described as a coastal form.

Key to the species of
-Telson narrowly long triangular, lateral margin armed with spines throughout its entire length In male, exopod of fourth pleopod with first and second segments armed with a pair of plumose setae, and second and third one subequal in length