Corresponding author: Mitsuyasu Moriya (
Academic editor: A. Myers
Two new species of
Moriya M, Srinui K, Sawamoto S (2015) Two new species of the genus
The genus
Currently, the genus
The present paper reports two new species of the subgenus
Mysid specimens were collected with a hand net by skin diving in a coral reef in Thailand (see “Systematics” section for details). The mysids from the net samples were immediately fixed in 5% seawaterbuffered formalin for morphological analysis and 99% ethanol for genetic analysis, the results of which will be reported elsewhere.
Terminology was mainly based on
body length
(BL) of the specimens was measured from the anterior end of rostrum to the posterior end of telson as the body was stretched. Illustrations were made with the aid of a camera lucida.Type specimens are housed in the
National Museum of Nature and Science, Japan
(NSMT).Holotype (
Body slender (Fig.
Eyes large, cornea globular, extending laterally beyond the lateral margin of carapace (Fig.
Antennular peduncle more robust in male (Fig.
Antennal scale slightly beyond anterior margin of antennular peduncle in male (Fig.
Mandibular palp (Fig.
First thoracopodal endopod (Fig.
Abdomen (Fig.
First, second, third, and fifth pleopods of males and all pleopods of females rudimentary. Fourth male pleopod (Fig.
Uropod (Fig.
Telson (Fig.
The specific name is derived from Latin
The most noticeable characteristic of
Morphological differences among





Carpopropodus of 3^{rd} to 8^{th} thoracopodal endopod  3^{rd }to 6^{th} divided distally into 2 segments  Unsegmented  Unsegmented  8^{th} divided distally into 2 segments (at least) 
Exopod of 4^{th} male pleopod: length  Anterior margin of 6^{th} abdominal somite  Backwards to level of the apical lobes of the telson  Middle of telson  Backwards to the posterior end of the 5^{th} abdominal somite 
Telson: apical cleft  Deep  Deep  Deep  Deep 
Spines on each lateral margin of telson  12 or 13  9 or 10  10  11 or 12 (9 or 10) 
Spines on each lateral margin of telson cleft  8  0 (unarmed)  0 (unarmed)  6 (4) 
Redescribed by
Only known from the type locality.
Holotype (
Body slender (Fig.
Eyes large, cornea occupying half of eye in dorsal view (Fig.
Antennular peduncle more robust in male (Fig.
Antennal scale (Fig.
Mandibular palp (Fig.
First thoracopodal endopod (Fig.
Abdomen (Fig.
First, second, third, and fifth pleopods of male and all pleopods of female rudimentary. Fourth male pleopod (Fig.
Uropod slender, setose around (Fig.
Telson (Fig.
The species is named after the type locality.
The most noticeable characteristic of
The type locality and Ko Chueak, Hat Chao Mai National Park, Trang Province, Thailand.
1  Body rather strongly built, gibbous; abdomen flexed ventrally; eye large, with cornea divided into two parts by groove 

–  Body slender, straight; eye globular, expanded, not divided into two portions 

2  Mandibular palp with second segment armed with triangular processes on mesial margin 

–  Mandibular palp with second segment armed with normal setae on both margins 

3  Carapace with spinules on anterolateral margin; telson with unarticulated denticles on lateral margin 

–  Carapace without spinules on anterolateral margin; telson with articulated denticles on lateral margin 

1  Telson longer than last abdominal somite 

–  Telson shorter than last abdominal somite 

2  Telson without distal cleft 

–  Telson with distal cleft 

3  Telson triangular with narrow apex 

–  Telson with rounded or truncate distal margin 

4  Rostrum triangular with narrowly rounded apex; exopod of fourth male pleopod with second segment 1/3 as long as third segment; marginal spines of telson increasing distally in length, apical spine 3 times as long as broad at base 

–  Rostrum broadly rounded or triangular with broadly rounded apex; exopod of fourth male pleopod with second segment about 4/5 as long as third segment; marginal spines of telson subequal in length, apical spine 1.5 times as long as broad at bas 

5  Distal margin of telson rounded 

–  Distal margin of telson truncate or weakly truncate 

6  Telson 1.5 times as long as broad, with 10–12 spines on posterior half of each lateral margin 

–  Telson nearly twice as long as broad, with 7–8 spines on posterior 2/3 of each lateral margin 

7  Telson with constriction, more than 10 spines on each lateral margin 

–  Telson without constriction 

8  Telson armed with 4–5 spines on each lateral margin 

–  Telson armed with 9–13 spines on each lateral margin 

9  Telson rounded triangular with weakly truncate distal margin; distal spines of telson subequal in size 

–  Telson trapezoid with truncate distal margin; distal spines of telson longer and stouter than lateral spines 

10  Each lateral margin of telson with 9 spines. Exopod of fourth male pleopod reaching tip of telson 

–  Each lateral margin of telson with 10–13 spines. Exopod of fourth male pleopod reaching beyond base of telson 

11  Inner margin of telson cleft unarmed with spines 

–  Inner margin of telson cleft armed with spines 

12  Uropodal endopod with process on mesial margin of statocyst region 

–  Uropodal endopod without process on mesial margin of statocyst region 

13  Process on uropodal endopod blunt, without articulation at base 

–  Process on uropodal endopod acutely pointed, with articulation at base 

14  Each apical lobe of telson with single spine 

–  Each apical lobe of telson with 2 or 3 spines 

15  Telson cleft about half of telson length 

–  Telson cleft less than 1/3 of telson length 

16  Rostrum pointed; eyestalk with papilliform process; telson with 2 or 3 spines on lateral margin of each posterior lobe 

–  Rostrum rounded; eyestalk without papilliform process; telson with 5 or 6 spines on lateral margin of each posterior lobe 

17  Each lateral margin of telson with 11–20 spines 

–  Each lateral margin of telson with less than 10 spines 

18  Each lateral margin of telson with 5–9 short slender spines. Cleft of telson 1/3 length of telson 

–  Each lateral margin of telson with 3 small spines. Cleft of telson 1/5 length of telson 

19  Telson narrowing abruptly at distal 1/3, each lateral margin with 2 spines at narrow part; each apical lobe of telson with 2 short spines 

–  Telson gradually narrowing, each lateral margin with more than 4 spines; each apical lobe of telson with 2 or 3 spines 

20  Telson with Vshaped cleft, each lateral margin with 7–11 spines; each apical lobe of telson with 2 spines 

–  Telson with Ushaped cleft, each lateral margin with 4–7 spines 

21  Each apical lobe of telson with 3 spines, each lateral margin armed with 6 or 7 spines 

–  Each apical lobe of telson with 2 spines, each lateral margin armed with 4 to 6 spines 

22  Posterior margin of telson narrow; each apical lobe of telson with 1 spine 

–  Posterior margin of telson broad; each apical lobe of telson with more than 3 spines 

23  Distal margin of telson with median depression, armed with more than 4 spines 

–  Distal margin of telson with slight median sinus, armed with 2 spines 

24  Bottom of telson cleft convexed 

–  Bottom of telson cleft rounded 

25  Telson 1.3 times as long as broad. Exopod of fourth male pleopod not extending beyond anterior margin of telson 

–  Telson 1.5 times as long as broad. Exopod of fourth male pleopod extending to distal end of telson 

26  Telson cleft with bottom spines only 

–  Telson cleft with spines entirely covered 

27  Exopod of fourth male pleopod extending to anterior margin of last abdominal somite 

–  Exopod of fourth male pleopod extending to or beyond posterior margin of last abdominal somite 

28  Apical cleft as long as 1/9 of telson, each lateral margin of telson with 3 or 4 spines 

–  Apical cleft as long as 2/5 of telson, each lateral margin of telson with 5 or 6 spines 

29  Exopod of fourth male pleopod extending to middle of telson, second segment 1.6 times longer than third 

–  Exopod of fourth male pleopod extending slightly beyond anterior margin of telson, second segment slightly longer than third 

30  Distal margin of telson armed with 2 or 3 pairs of long and robust spines  31 
–  Distal margin of telson without long and robust spines 

31  Posterior margin of telson broader than basal width, with 3 pairs of long and robust spines, about 1/3 of telson length 

–  Posterior margin of telson equal to or narrower than basal width, with 2 pairs of long and robust spines, about 2/5 of telson length 

32  Telson 1.3–1.4 times as long as broad 

–  Telson 1.5–1.8 times as long as broad 

33  Posterior 2/3 of telson gradually narrowing distally; lateral spines of telson considerably reduced in size 

–  Posterior 1/4 to 1/3 of telson almost parallelsided; lateral spines of telson normally developed 

34  Rostrum broadly rounded; uropodal endopod subequal to exopod in length; length ratios of 3 exopod segments of fourth male pleopod 3.1 : 1 : 1.5 

–  Rostrum triangular with rounded apex; uropodal endopod clearly shorter than exopod; length ratios of 3 exopod segments of fourth male pleopod 5.5 : 1 : 2.6 

35  Lateral spines of telson considerably reduced in size 

–  Lateral spines of telson normally developed 

36  Antennal scale not extending to distal end of antennular peduncle in male, slightly beyond in female, 6 times as long as broad; telson 1.5 times as long as broad, with 7 spines on each lateral margin 

–  Antennal scale extending beyond distal end of antennular peduncle in both sexes, 7 times as long as broad; telson 1.7 times as long as broad, with 8 or 9 spines on each lateral margin 

37  Lateral depression of telson clear at distal quarter; distal margin of telson broad, with 4 or 5 pairs of long spines 

–  Lateral depression of telson very slight if present; distal margin of telson narrow, with 3 pairs of long spines 

In the middle of September 2015, the subgenus
We wish to thank Prof. S. Nishida, at the University of Tokyo, for providing us with the opportunity for sampling in Southeast Asia. Thanks are also due to all those who supported our study, particularly Dr. S. Satapoomin, at the Phuket Marine Biological Center, Thailand. We thank Prof. Ephrime B. Metillo and an anonymous referee for helpful comments and advice on the manuscript. This study was partially supported by the Asian CORE Program of the Japan Society for the Promotion of Science.