Oratosquilla Manning, 1968

Ahyong, Shane T., 2002, Stomatopoda (Crustacea) from the Marquesas Islands: results of MUSORSTOM 9, Zoosystema 24 (2), pp. 347-372 : 365-367

Genus Oratosquilla Manning, 1968

Oratosquilla fabricii ( Holthuis, 1941) ( Fig. 9 )

Squilla fabricii Holthuis, 1941: 249-253 , fig. 1. Type locality: Telok Dalam, Eil Nias, Indonesia.

Squilla calumnia Townsley, 1953: 410 , figs 8, 9. Type locality: Hawaii.

Squilla oratoria – Townsley 1953: 404, figs 2, 3 [non Squilla oratoria de Haan, 1844 ].

Oratosquilla calumnia – Manning 1971b: 4-6, fig. 1. — Moosa 1991: 210, 211. — Ahyong & Norrington 1997: 107. — Poupin 1998: 37.

Oratosquilla mauritiana – Garcia 1981: 24-26 [non O. mauritiana ( Kemp, 1913) ].

Busquilla quadraticauda – Poupin 1998: 37 [non B. quadraticauda (Fukuda, 1911) ].

Oratosquilla fabricii – Ahyong 2000: 926-930, fig. 1.

MATERIAL EXAMINED. — Eiao, stn CP1156, 7°59.0’S, 140°43.7’W, 80 m, 23.VIII.1997, 1 juvenile broken cl 6.5 ( MNHN). — Stn CP1158, 7°58.7’S, 140°43.9’W, 109-110 m, 23.VIII.1997, AS 5-6 and telson (length 28 mm) ( MNHN). — Stn DW1266, 7°57.3’S, 140°42.6’W, 84 m, 04.IX.1997, 1 juvenile tl 33 ( MNHN). — Stn DW1279, 7°59.4’S, 140°42.2’E, 23-70 m, 06.IX.1997, 1 tl 54, 2 tl 27, 1 sex indet. (anterior cephalon only, cl <20) ( MNHN). — Nuku Hiva, stn DW1184, 8°49.3’S, 140°03.6’W, 23-30 m, 26.VIII.1997, 2 tl 48, 1 broken tl> 19 ( MNHN). — Stn DW1185, 8°48.9’S, 140°03.4’W, 31-33 m, 26.VIII.1997, 1 juvenile tl 41 ( MNHN). — Stn DW1186, 8°48.1’S, 140°03.5’W, 42-45 m, 26.VIII.1997, 1 broken cl 9.3 ( MNHN). — Stn CP1187, 8°49.2’S, 140°03.5’W, 25-30 m, 26.VIII.1997, 2 tl 37-63 ( MNHN). — Stn CP1188, 8°48.6’S, 140°03.4’W, 35-55 m, 26.VIII.1997, 1 tl 35 ( MNHN). — Stn DW1211, 9°50.2’S, 139°02.5’W, 50 m, 29.VIII.1997, 1 tl 55 ( MNHN). — Hiva Oa, stn CP1212, 9°49.9’S, 139°02.2’W, 50-80 m, 29.VIII.1997, 2 tl 29-47 ( MNHN). — Stn DW1214, 9°49.8’S, 140°03.1’W, 25-40 m, 29.VIII.1997, 1 tl 40, 1 juvenile tl 30, 1 postlarva tl 28 ( MNHN). — Stn DW1224, 9°44.6’S, 138°51.1’W, 115-120 m, 30.VIII.1997, 1 tl 28 ( MNHN). — Stn DW1225, 9°45.2’S, 138°52.6’W, 42-70 m, 30.VIII.1997, 3 postlarvae tl 26-27, 5 postlarvae tl 27-28 ( MNHN). — Stn CP1226, 9°45.3’S, 138°52.6’W, 38-77 m, 30.VIII.1997, 2 postlarvae tl 27-28, 1 postlarva tl 29 ( MNHN). — Stn CP1228, 9°44.6’S, 138°51.5’W, 107-108 m, 30.VIII.1997, 2 tl 28-41 ( MNHN). — Fatu Hiva, stn DW1241, 10°27.8’S, 138°40.6’W, 85-130 m, 01.IX.1997, 1 postlarva tl 27 ( MNHN). — Stn DR1245, 10°29.2’S, 138°36.2’W, 85-130 m, 01.IX.1997, 1 postlarva tl 24 ( MNHN).

MEASUREMENTS. — Male (n = 16) tl 24-63, female (n = 18) tl 27-41, 1 sex indet. cl <20, male postlarvae (n = 8) tl 24-28, female postlarvae (n = 6) tl 26-29.

DISTRIBUTION. — Widely distributed in the central and western Pacific from the Philippines, New Caledonia, Guam, Fiji, Hawaii, Tahiti and the Marquesas.

REMARKS

The present series of specimens provides strong support for Manning’s (1971b) association of the juvenile holotype of Squilla calumnia Townsley, 1953 , with adults from Hawaii (all as O. calumnia ). As mentioned by Manning (1971b), characters diagnostic for adults are often undeveloped in postlarvae and juveniles. Townsley’s (1953) account of the holotype of S. calumnia agrees well with the postlarvae reported below. Ahyong (2000) showed that O. calumnia is a junior synonym of O. fabricii . In the present material, postlarvae show reduced carinae and lack anterolateral spines on the carapace, the rostral plate bears a median carina, the lateral processes of TS5-7 are indistinctly bilobed, fewer carinae on the abdominal somites are armed, the tubercles on the dorsal carina on the carpus of the raptorial claw are undeveloped as is the tooth on the outer margin of the merus of the raptorial claw. In most of these characters, particularly in the morphology of the TS5-7 lateral processes, postlarval O. fabricii resemble adults of Busquilla Manning, 1978 ; the specimen from Tahiti reported by Poupin (1998) as B. quadraticauda (MNHN Sto 1961) is a juvenile of O. fabricii . By approximately tl 35, anterolateral spines on the carapace are well developed, the anterior bifurcation of the median carina on the carapace is usually interrupted, the carpus on the raptorial claw is irregular, the inferodistal margin on the merus of the raptorial claw is angular, the lobes on lateral processes of TS5-7 are better defined and the abdominal carinae are spined as follows: SM 5-6, IM 3-6, LT 2-6, MG 1-5. By tl 48, submedian carinae of AS 4 are armed posteriorly. Adult diagnostic characters are not shown until the tl exceeds 55 mm in which the median carina on the rostral plate more closely resembles a low tubercle, the median carina of the carapace is entire at the base of the anterior bifurcation, the carpus of the raptorial claw is distinctly tuberculate and the inferodistal angle is produced to a blunt tooth, the anterior lobes of the lateral processes of TS6-7 relatively slender, the penes are well developed and the abdominal spination is SM 4-6, IM (1)2-6, LT 1-6, MG 1-5.

Unfortunately, because diagnostic characters of adult O. fabricii do not develop until a relatively large size (tl> 55), the “slow” development of the anterior bifurcation of the carapace and submedi- an spines of AS 4 could confound specific as well as generic assignment. The single distinguishing character between Oratosquilla Manning, 1968 , and Oratosquillina Manning, 1995 is the condition of the anterior bifurcation of the median carina of the carapace, whether uninterrupted or interrupted basally. Moreover, many stomatopod species show adult characters at a considerably smaller size than O. fabricii . Therefore, the degree of development of the male penes and modified pleopod 1 endopod should be considered (as a surrogate for sexual maturity), particularly when identifying small specimens. Juveniles shorter than tl 55 could easily be confused with juvenile Oratosquillina asiatica (Manning 1978) because of the presence of the rostral carina, interrupted median carina of the carapace, irregular or tuberculate carpal carina of the raptorial claw and armed submedian carinae of AS 4 in some specimens. The preserved colour pattern of the two species is similar, but in O. fabricii the distal segment of the uropodal exopod is dark on the inner half and the anterior lobe of the lateral process of TS7 is a large conspicuous lobe, whereas in Oratosquillina asiatica , the distal segment is dark only on its inner proximal third or quarter and the anterior lobe of the lateral process of TS7 is present as a small point.

It is noteworthy that several of the juvenile characters of Oratosquilla fabricii are retained by adults of Quollastria Ahyong, 2001 , and Oratosquillina Manning, 1995 . Hence, species of Oratosquillina and Quollastria bear the interrupted anterior bifurcation of the median carina of the carapace and an uninterrupted dorsal carpal carina of the raptorial claw (in most species of Oratosquillina ) suggesting retention of paedomorphic characters in adults of the two genera. As noted by Ahyong (2001), adults of Busquilla retain many features of postlarval or juvenile Oratosquilla . The role of heterochrony in the radiation of the stomatopods warrants further study.

Figures

FIG. 9. — Oratosquilla fabricii (Holthuis, 1941); A-D, postlarva tl 29 mm (stn DW1241); A, anterior cephalon; B, TS5-8, right dorsal; C, raptorial claw carpus, right lateral; D, uropodal protopod, right ventral; E-H, juvenile tl 30 mm (stn DW1214); E, anterior cephalon; F, TS5-8, right dorsal; G, raptorial claw carpus, right lateral; H, uropodal protopod, right ventral; I-L, tl 63 mm (stn CP1187); I, anterior cephalon; J, TS5-8, right dorsal; K, raptorial claw, right lateral; L, uropodal protopod, right ventral. Scale bar: A-H, 1.5 mm; I-L, 3 mm.