Orientomysis pseudomitsukurii ( Ii, 1964 ) Fukuoka & Murano, 2005

Fukuoka, Kouki & Murano, Masaaki, 2005, A revision of East Asian Acanthomysis (Crustacea: Mysida: Mysidae) and redefinition of Orientomysis, with description of a new species, Journal of Natural History 39 (9), pp. 657-708 : 682-683

Orientomysis pseudomitsukurii ( Ii, 1964) comb. nov.

( Figure 6 ) Acanthomysis pseudomitsukurii Ii 1964: 513–516 , Figure 133; Mauchline and Murano 1977: 45 (list); Müller 1993: 196, 197 (list).

Type locality

Coast near Marine Biological Center of Tokyo Bunrika University (now University of Tsukuba ), Shimoda, Shizuoka, central Japan .

Material examined

Sixty-three males (5.2–8.5 mm) and 54 females (4.5–8.2 mm), Nii-jima Island, Izu Islands, central Japan, among seaweeds, May 1973, coll. M. Muto, NSMT-Cr 15581. One female (6.9 mm), Uchiura Bay , Chiba, central Japan, 29 April 1975, NSMT-Cr 15582. One female (8.0 mm), Fukiage-hama Beach, East China Sea side of Kagoshima, western Japan, 20 March 1988, coll. T. Noichi, NSMT-Cr 15583. Three females (8.0– 8.5 mm), Fukiage-hama Beach, Kagoshima, western Japan, 21 March 1988, coll. T. Noichi , NSMT- Cr 15584. Nine males (5.7–6.7 mm), three immature males (4.5–5.3 mm) and 18 females (5.5–7.5 mm), Tottori, western Japan, 5 m, sledge net, 8 June 1988, coll. Y. Hirota, NSMT-Cr 15585. Two males (5.5 and 6.3 mm), Banda Beach , Tateyama , Chiba, central Japan, 4 m, sledge net, 13 July 1994, coll. K. Fukuoka, NSMT-Cr 15586. Two females (6.1 and 6.2 mm), Banda Beach , Tateyama , Chiba, central Japan, 0–0.5 m, sandy beach, sledge net, 20 September 1994, coll. K. Fukuoka, NSMT-Cr 15587. Fourteen males (7.8– 9.8 mm) and 19 females (7.3–9.5 mm), Tottori, western Japan, date unknown, NSMT-Cr 15588 .

Remarks

Location of type specimens is unknown.

Some differences exist between Ii’s description and the present specimens. According to Ii (1964), the eyestalk was not armed with a papilliform process on the dorsal surface, whereas a small but distinct process is present in our material. Ii (1964) also described a single distinct transverse dorsal fold on each of the second to fourth abdominal somites, but the state of the abdomen varies with individuals in the present specimens ( Figure 6 ; Table VII). The folds on the second to fifth abdominal somites are frequently indistinct.

Orientomysis pseudomitsukurii resembles O. leptura and O. tenella . Differences among these three species are summarized in Table V.

Distribution

This species is recorded only from the Japanese warm water region: Shizuoka ( Ii 1964), Yamaguchi, Tottori ( Hirota et al. 1989), Nii-jima Island of Izu Islands, Chiba, and western Kagoshima (present study).

In Japan Sea coasts, this species is abundantly distributed in depths of 4–5 m ( Hirota et al. 1989). They were collected from near shoreline and among seaweeds (present study).

Figures

Figure 6. Orientomysis pseudomitsukurii (Ii 1964) comb. nov. First to sixth abdominal somites, lateral. (A) Female (7.5 mm), Nii-jima Island, Pacific, NSMT-Cr 15581; (B) female (8.2 mm), Nii-jima Island, NSMT-Cr 15581.