Thyraplax cooki ( Rathbun, 1906 ) Castro, 2007

Castro, Peter, 2007, A reappraisal of the family Goneplacidae MacLeay, 1838 (Crustacea, Decapoda, Brachyura) and revision of the subfamily Goneplacinae, with the description of 10 new genera and 18 new species, Zoosystema 29 (4), pp. 609-774 : 676-677

publication ID	https://doi.org/ 10.5281/zenodo.4525564
persistent identifier	https://treatment.plazi.org/id/102B87CB-FFC1-2526-FF2C-FD5BFE9FF97C
treatment provided by	Felipe
scientific name	Thyraplax cooki ( Rathbun, 1906 )
status	comb. nov.

Treatment

Thyraplax cooki ( Rathbun, 1906) View in CoL n. comb.

Pilumnoplax cooki Rathbun, 1906: 830 View in CoL [in list], 835, pl. 7, fig. 3 [Hawaiian Is]. — Tesch 1918: 155 [in list]. — Edmondson 1962: 3, fig. 1a [Hawaiian Is]. — Serène 1968: 90 [in list].

Carcinoplax cooki – Guinot 1969b: 524 [discussion], figs 60, 77, 78; 1971: 1081 [in list]; 1989: 314 [in list], fig. 42, pl. 11, figs G, H [Hawaiian Is]. — Serène & Lohavanijaya 1973: 62 [in list], 64 [in key].

TYPE MATERIAL. — Albatross, stn 3866, ♂ holotype, cl 12.7 mm, cw 14.9 mm ( USNM 29364).

TYPE LOCALITY. — Hawaiian Islands, Pailolo Channel between Moloka‘i and Maui, 468- 538 m.

MATERIAL EXAMINED. — Hawaiian Islands. Pailolo Channel, between Moloka‘i and Maui, Albatross, stn 3866, 21°12’N, 156°35’W, 468-538 m, 10.IV.1902, ♂ holotype ( USNM 29364). — Pailolo Channel, Mokukroniki islet, Albatross, stn 3865, 21°09’N, 156°35’W, 468 m, 10.IV.1902, California Academy of Sciences leg., 1 ♂ ( MNHN-B 10557).

New Caledonia. BERYX 11, stn DW 09, 24°52’S, 168°22’E, 635-680 m, 15.X.1992, 1 ♂, 1 pre-adult ♀ ( MNHN-B 29564).

NORFOLK 2, stn DW 2055, 23°39’S, 168°16’E, 900- 950 m, 24.X.2003, 1 ♀ ( MNHN-B 29765).

French Polynesia. Austral Is, BENTHAUS 2002, stn DW 1889, 27°36.8’S, 144°15.7’W, 600-620 m, 7.XI.2002, 1 ♀ ( MNHN-B 29789). — Stn DW 1957, 23°18.8’S, 149°29.3’W, 558-1000 m, 18.XI.2002, 1 pre-adult ♀ ( MNHN-B 29782). — Stn DW 1961, 23°29.9’S, 149°33.5’W, 470-800 m, 19.XI.2002, 1 pre-adult ♀ ( MNHN-B 29783). — Stn DW 1965, 23°21.3’S, 149°33.9’W, 500-1200 m, 19.XI.2002, 1 ♀ ( MNHN- B 29785). — Stn DW 2004, 22°27.7’S, 151°18.7’W, 430-850 m, 24.XI.2002, 1 pre-adult ♀ ( MNHN-B 29788). — Stn DW 2010, 22°32.4’S, 151°20.8’W, 520-950 m, 24.XI.2002, 2 ♂♂ ( MNHN-B 29781).

Marquesas Is, MUSORSTOM 9, stn DW 1275, 07°53’S, 140°38’W, 627 m, 5.IX.1997, 1 ♂ ( MNHN-B 29548). — Stn CP 1276, 07°52’S, 140°37’W, 800-805 m, 5.IX.1997, 2 ♂♂ ( MNHN-B 29549).

DISTRIBUTION. — Hawaiian Is ( Rathbun 1906) and now French Polynesia, Fiji, and New Caledonia. Depth: 430-1000 m. Also dredged from a station recorded at 500-1200 m.

REMARKS

Guinot (1969b: 524) placed T. cooki n. comb. by itself in one of three groups of Carcinoplax sensu lato. Several characters were given for this classification: G1 “analogous” to those of C. longimana (de Haan, 1833) , relatively narrow sternum (particularly near the chelipeds and on the posterior portion), and narrow male abdomen.

Thyraplax cooki n. comb. is close to T. crosnieri n. comb. in the shape of the carapace, the size of the chelipeds (P1), and in the relative length of the ambulatory legs (P2-P5). The anterolateral margin of T. cooki n. comb. has a slight tooth-like eminence (see Guinot 1989: fig. 42, pl. 11, fig. G), which was described as a “blunt obtuse-angled tooth” in the original description ( Rathbun 1906: 835). In contrast, the margin of T. crosnieri n. comb. has a slight carina that is sometimes marked by a median notch ( Fig. 13C View FIG ). The anterolateral teeth are dorsally oriented (although more conspicuously so in T. cooki n. comb.) and obtuse in both species, but were nevertheless found to be acute in some specimens of T. cooki n. comb. The main differences that separate the two species are in the morphologies of their G1, G2, and vulvae respectively. The G1 of T. cooki n. comb. is slender, straight, and its distal portions provided with small teeth ( Guinot 1969b: fig. 77a, b) whereas that of T. crosnieri n. comb. is stouter and the distal third portion bent outwardly ( Guinot & Richer de Forges 1981b: fig. 10I). The G2 of T. cooki n. comb. is straight, with two equal apical spinules ( Guinot 1969b: fig. 78) whereas that of T. crosnieri n. comb. is slightly bent distally and the tip has two unequal spinules ( Guinot & Richer de Forges 1981b: fig. 10L). The vulva of T. cooki n. comb. is large, round, and it extends from su- ture 5/6 to suture 6/7 of thoracic sternite 6. Each vulva has a small, spherical, low vulvar cover on its postero-external margin that does not reach the anterior margin of the vulva. The vulva of T. crosnieri n. comb. ( Fig. 19 View FIG ) is in the same position but the opening is oval, smaller than in T. cooki n. comb., and the vulvar cover is large and triangular.

Somite 6 of the abdomen of the male holotype ( USNM 29364) and of a second male from the type locality ( MNHN-B 10557) showed a slight triangular eminence on the outer margin of each distal end, a character not observed among the males from French Polynesia and New Caledonia that were examined. Otherwise, all other characters of the two Hawaiian specimens agreed with those from southern localities.