Bathypilumnus pugilator (A. Milne-Edwards, 1873 )

Manikandan, K, Megalaa, N, Valliappan, Subramanian, Nandini, K, Rani, Lourdu V, Dakshinamurthi, Senthil & Nagappan, Nagappan, 2022, Crabs (Crustacea, Decapoda) from the Seas of East and Southeast Asia Collected by the RV Hakuhō Maru (KH- 72 - 1 Cruise) 3. Sahul Shelf, Bulletin of the National Museum of Nature and Science. Series A, Zoology 48 (2), pp. 35-83 : 67

Bathypilumnus pugilator (A. Milne-Edwards, 1873)

( Fig. 15D–E )

Material examined. RV Hakuhō Maru KH-72-1 cruise, sta. 29, 1 Ə ( CB 7.9 mm including lateral teeth×CL 5.9 mm), NSMT-Cr 30743; 1 $ (15.6×11.0 mm), 1 juv. (4.0× 3.3 mm), NSMT-Cr 30744.

Remarks. Ng and Tan (1984) established Bathypilumnus , a new genus for two Pilumnus species, P. sinensis Gordon, 1930 and P. nigrispinifer Griffin, 1970. Later, Davie (1989) reassigned Actumnus pugilator A. Milne-Edwards, 1873 , to Bathypilumnus in discussion on the establishment of a new genus Takedana . In these three congeneric species, the general form of the carapace, chelipeds and ambulatory legs are generally close to those of Pilumnus , but the carapace dorsal surface is strongly convex and vaulted longitudinally and transversely, both chelipeds are heavy, with strong heterochely, the male pleon is narrow, and the G1 is simple and long, differing from the so-called Pilumnus - type with the recurved tip.

In one pair of the specimens of B. pugilator examined, both chelipeds and most of the ambulatory legs are missing in female and male, respectively. The strongly vaulted carapace is covered only with short setae, not granulated, and has the shallow interregional furrows. The front is divided into two convex lobes fringed with minute granules, with a small, but sharp lateral lobule close to the supraorbital angle; the dorso-frontal view shows that each frontal lobe is deeply separated by a wide V-shaped notch and is strongly convex anteriorly along the inner half and shallowly concave just inside of the lateral lobe. The external orbital angle is armed with a small obtuse granule and followed by some smaller granules on the carapace margin to the first anterolateral tooth. The three anterolateral teeth behind the external orbital angle are conical and stout in dorsal view, being subequal and projecting regularly from the first to the third.

Both chelipeds are heavy and prominently armed on the carpus and palm ( Fig. 15D–E ). On the larger chela, the outer surfaces of the carpus and palm are armed with several longitudinal lines of mushroom-like tubercles; in each line, several mushrooms are connected through the truncated umbrella; the outer lower surface is covered with conical, tuberculate granules of good size. On the smaller chela, the mushroom tubercles are replaced by rows of the tall and subtruncated tubercles on the upper surface and armed with rows of conical tubercles on the whole outer surface. The pleon is narrow, with a remarkably narrow and slender telson.

There seem to be no recent records of this species, but the present specimens agree well with the original description and figures.

Distribution. Originally reported from Lifou Island in New Caledonia. Davie (2002) recorded this species from Queensland coast, on sand and shell substrates, from the shallow subtidal to about 20 m depth. Poore et al. (2008) recorded this species from Western Australia, 100 m depth. The present specimens were collected at a depth of 49–52 m and represents the first record from the Northern Territory, Australia.

Figures

Fig. 15.ɹA–C: Camptoplax coppingeri Miers, Ə (NSMT-Cr 30745; CB 5.7×CL 4.5mm) from sta. 29. D–E: Bathypilumnus pugilator (A. Milne-Edwards), Ə (NSMT-Cr 30743; CB 7.9×CL 5.9mm) from sta. 29.