Thyraplax truncata Castro, 2007

Castro, Peter, 2009, Two new species of Carcinoplax H. Milne Edwards, 1852, and Pycnoplax Castro, 2007, from the western Pacific, and a description of the female of Thyraplax truncata Castro, 2007 (Crustacea, Decapoda, Brachyura, Goneplacidae), Zoosystema 31 (4), pp. 949-957 : 956-957

Thyraplax truncata Castro, 2007

( Fig. 3 )

Thyraplax truncata Castro, 2007: 683 , figs 25, 26. — Ahyong 2009: 66, fig. 1A-C.

MATERIAL EXAMINED. — New Caledonia. EBISCO, stn CP 2498, 24°45.0’S, 159°43.0’E, 367-536 m, 6.X.2005, 1 ♀, 7.2 mm, cw 9.7 mm (MNHN-B30794).

REMARKS

Thyraplax truncata , was described from five specimens, all males, which were collected from depths of 430- 500 m in New Caledonia and Fiji. Ahyong (2009) subsequently recorded a female from the Kermadec Is., New Zealand. A second female specimen from New Caledonia now permits the description of the female. All characters related to the morphology of the carapace and pereopods ( Fig. 3A ) agree with those described for the males ( Castro 2007: 683, figs 25A, 26). One exception is the dark-brown tip of the cheliped fingers, which extended slightly less in the female than in the five males previously studied.

DESCRIPTION OF THE FEMALE

Abdomen wide.Telson triangular,slightly wider than long. Somite 3 covers space between P5 coxae and episternites 7, somite 2 only slightly narrower than somite 3, thoracic sternite8not visible.Vulva ( Fig.3B ) crescent-shaped, extending from edge of anteriorly deflected suture 5/6 to middle portion of thoracic sternite 6; small, triangular sternal vulvar cover on posterior margin of vulva, covering about third of aperture, soft membrane covering rest of aperture.

Figures

FIG. 3. — Thyraplax truncata Castro, 2007, ♀, cl 7.2, cw 9.7 mm, New Caledonia, EBISCO, stn CP 2498 (MNHN-B30794): A, dorsal view; B, thoracic sternum and vulvae.