Halocaridinides trigonophthalma ( Fujino and Shokita, 1975 )

Cai, Y., 2006, Atyid shrimps (Crustacea: Decapoda: Caridea) of the Ryukyu Islands, southern Japan, with descriptions of two new species, Journal of Natural History 40 (38 - 40), pp. 2123-2172 : 2130-2133

Halocaridinides trigonophthalma ( Fujino and Shokita, 1975)

Halocaridina (Halocaridinides) trigonophthama Fujino and Shokita, 1975, p 106 , figs.7, 8

[type locality: several wells in Okinawa Island, Ryukyus, Japan].

Halocaridina (Halocaridinides) trigonophthama: Shokita and Nishijima 1976, p 71 ; Shokita

1979, p 201.

Palauatya dasyomma Hart, 1980, p 481 , figs.1–31 [type locality: Anguar Island , Palau, Caroline Islands].

Halocaridinides trigonophthalma: Holthuis 1982, p 31 , fig. 3a–u; Gurney 1984, p 591; Hayashi 1989e, p 497, fig.177; Shokita 2002, p 164; 2003, p 249, fig. 17C; 2006b, p 62; Naruse et al. 2003, p 1; Yoshigou et al. 2003, p 9; Fujita and Shokita 2005a, p 194.

Material examined

Holotype: male, cl 2.4 mm, URB-497, well near Kaneshi, Okinawa Island, Ryukyu Islands , coll S. Shokita, November 1971 . Allotype: 1 female, cl 2.8 mm, URB-498, well near Kaneshi, Okinawa Island, Ryukyu Islands , coll S. Shokita, November 1971 . Paratypes: 2 males, cl 2.0– 2.4 mm, URB-499, well near Kaneshi, Okinawa Island, Ryukyu Islands , coll S. Shokita, November 1971 . Others : 1 specimen, URB, Shiokawa, Okinawa Island, Ryukyu Islands , coll T. Nagai, March 1997 ; 4 female cl 3.0– 3.6 mm (RUB-ZC-78-81), 1 male cl 2.6 mm (RUB-ZC-82), Hatoma Island, Yaeyama Group, Ryukyu Islands , coll. M. Toda, 18 October 2002 .

Diagnosis

Rostrum short, not reaching beyond end of eyestalk; unarmed. Antennal spine fused fully with inferior orbital angle. Pterygostomian margin broadly rounded. Telson not terminating in a projection, with only two pairs of dorsal spinules on distal two-thirds of telson; with two pairs of distal spines, lateral pair of distal spines distinctly longer than intermediates. Antennular peduncle 0.55 times as long as carapace, stylocerite not reaching to end of basal segment of antennular peduncle. Epipods on first three pereiopods. Merus of first pereiopod as long as ischium; carpus of first pereiopod deeply excavated, subequal to chela in length, 3.3 times as long as high, chela 2.3 times as long as broad, fingers distinctly longer than palm. Merus of second pereiopod as long as ischium; carpus of second pereiopod excavated anteriorly, very slender, seven times as long as high, more than twice longer than chela; chela 2.5 times as long as broad, fingers 1.6 times as long as palm. Propodus of third pereiopod three times as long as dactylus, dactylus 2.5 times as long as wide, with eight spines on flexor margin. Propodus of fifth pereiopods three times as long as dactylus, dactylus 3.5 times as long as broad, with 18–19 spinules on flexor margin. Endopod of male first pleopod subrectangular, no appendix interna, slightly shorter than exopod. Appendix masculina of male second pleopod slender. Uropodal diaeresis with four movable spinules.

Habitat

Anchialine caves.

Remarks

Halocaridinides Fujino and Shokita 1975 , was originally established as a subgenus of Halocaridina . Palauatya was established based on Palau material by Hart (1980). Based on a collection from Palau, Holthuis (1982) synonymized Palauatya with Halocaridinides and raised the latter to full generic rank. Halocaridinides trigonophthalma has been found from Okinawa Island, and Hatoma Island of the Ryukyu Islands (Fujiino and Shokita 1975; Shokita 1975, 1979; Naruse et al. 2003), Palau Islands ( Hart 1980; Holthuis 1982) and Guam ( Maciolek 1983). Gordon (1968, in Gordon and Monod 1968) described a new species from a subterranean lake in Kufile, Zanzibar, and doubtfully placed it in the genus Parisia Holthuis 1956 . Gurney (1984) moved it to Halocaridinides and redescribed it in detail as H. fowleri after re-examining the types. Halocaridinides trigonophthalma could be easily distinguished from H. fowleri by the relative position of the distal end of the antennal carpus (reaching as far as the distal end of the antennular peduncle in H. trigonophthalma vs. reaching as far as the distal end of the antennal scale in H. fowleri ). Naruse et al. (2003) used the relative length of the exopod of the third pereiopod against the endopod as one of two characters to differentiate H. trigonophthalma from H. fowleri . However this character is too slight to separate two species (see Hart 1980, Fig. 15 ; Gurney 1984, Fig. 2B ). The disjunct localities in the West Pacific may reflect a possible passive dispersal path by ocean current as suggested by Smith and William (1981) and Maciolek (1983).

Distribution

Known from the Ryukyu Islands, Japan, Palau, and Guam.

Figures

Figure 2. Paratya compressa. A, third maxilliped; B, first pereiopod; C, second pereiopod; D, third pereiopod; E, dactylus of third pereiopod; F, fifth pereiopod; G, dactylus of fifth pereiopod. Scales: A–D, F51 mm; E, G50.2 mm (female, cl 7.1 mm, ZRC 2004.0565).

Figure 15. Neocaridina ishigakiensis. A, cephalothorax and cephalic appendages; B, scaphocerite, C. mandible; D. maxillula, E. maxilla; F. first maxilliped; G. second maxilliped; H. third maxilliped; I. preanal carina. Scales: A, B51 mm; C–I50.5 mm (male, cl 4.7 mm, ZRC 2004.0584).