Pasiphaea alcocki ( Wood-Mason, 1891 )

Rodrigues, Thaiana G. A. & Cardoso, Irene A., 2019, First record of four Pasiphaea Savigny, 1816 (Crustacea, Decapoda, Pasiphaeidae) species from the southwestern Atlantic, Zootaxa 4560 (2), pp. 321-330 : 322

Pasiphaea alcocki ( Wood-Mason, 1891)

( Figure 1 )

Parapasiphae Alcocki Wood-Mason, 1891: 196 .

Pasiphaea (Phye) Alcocki — Wood-Mason, 1892: 3, fig. 5.

Phye Alcocki — Wood-Mason, 1893: 164.

Pasiphaea (Phye) alcocki — Alcock, 1901: 61.

Pasiphaea Alcocki — De Man, 1920: 2.

Pasiphaea alcocki —Komai & Amaoka 1993: 371; Hayashi, 2006a: 196, fig. 1–2; De Grave & Fransen, 2011: 257; Komai et al., 2012: 300, fig. 4.

Material Examined. REVIZEE, St. 0 538, 20°27.667’S, 39°38.101’W, 1680m, 1 female (15.61mm), MNRJ26958.

Diagnosis. Body soft, but not fragile. Rostrum short, without slit at base, apex not reaching anterodorsal margin of carapace. Carapace dorsally carinate at least at anterior half, without depression near base of rostrum ( Fig. 1A, B ). Branchiostegal sinus moderate and shallow; branchiostegal spine small, submarginal, apex extending beyond anterodorsal margin of carapace ( Fig. 1A ). First pereopod with 1–5 spines on merus, unarmed on ischium and basis, posterodistal angle of basis rectangular or bluntly produced ( Fig. 1C ). Second pereopod with 7–14 spines on merus, unarmed on ischium, basis with posterodistal tooth ( Fig. 1D ). First to fifth abdominal somites dorsally smooth, not carinate dorsally; sixth abdominal somite sharply carinate, with a lateral carina ( Fig. 1E, F ). Telson shallowly grooved in dorsal midline; posterior margin deeply forked, with 8–10 pairs of spines ( Fig. 1G, H ); telson shorter than sixth somite. Pleurobranch on the eighth thoracic somite (modified from Hayashi, 2006a).

Distribution. Type locality: Indian Ocean, Bay of Bengal (1611’15’’N, 8230’30’’E). Gulf of Manar and Arabian Sea. Indo-Pacific Ocean, South East Asia, Indonesia, Philippines and Taiwan (eastern and southern coast). New record: Atlantic Ocean, Brazil (Espírito Santo). Depth: 185 – 1733m.

Remarks. In our material the size was similar to observed by Hayashi (2006a), who examined females (cl: 14.1–21.0mm) and one male (cl: 13.8mm) from Indo-Pacific Ocean. The Brazilian material agrees with Hayashi (2006a) description in all diagnostic characters except by the sixth abdominal somite, that presented a slightly marked lateral carina ( Fig. 1E ) while Hayashi (2006a) observed a strongly marked carina.

Pasiphea alcocki is closely related to P. korzuni Burukovsky, 1995 . Both species share a carapace with acute dorsal carina, but P. alcocki presents only the sixth abdominal somite carinate ( Fig. 1F ) instead of two or more abdominal somites carinate ( Hayashi, 2006a).

Figures

FIGURE 1. Pasiphaea alcocki (Wood-Mason, 1891), female (15.61mm), MNRJ26958. A. Carapace, lateral view; B. Carapace, dorsal view; C. Left first pereopod, lateral view; D. Left second pereopod, lateral view; E. Sixth abdominal somite, lateral view; F. Sixth abdominal somite, dorsal view; G. Telson, dorsal view; H. Posterior margin of telson, dorsal view.