Achaeus brevirostris ( Haswell, 1879 )

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 : 44-46

Achaeus brevirostris ( Haswell, 1879) ( Figs. 5A, 11A–C)

Material examined. RV Hakuhō Maru KH-72-1

cruise, sta. 29, 1Ə ( CB 4.9×CL 7.2 mm), NSMT- Cr 30705; 1 Ə (5.1× 7.6 mm), NSMT-Cr 30706.

Remarks. Davie (2002) listed eight Australian species of the genus Achaeus , and two more species remained unidentified in Poore et al. (2008). This long-neck species identified as A. breviros- tris is characteristic in having the smooth carapace surface without prominent spines or tubercles. Although all the chelipeds and ambulatory legs are missing in the male examined ( Fig. 5A), the identification as A. brevirostris is reasonable, with some characters subject to variation. First, it is noted that the hepatic region of the carapace of the male is strongly developed as a triangular tooth in dorsal view and seems to be proportionally larger than the illustration of Griffin (1970: fig. 1a). There are otherwise some discrepancies in the number of granules on the branchial region, the shape of the male telson, and the curvature and twist of the G1, most of which have been difficult to illustrate and explain accurately. In this study, these differences ( Fig. 11A–B) are considered to represent individual or developmental variations.

Distribution. Indo-West Pacific from Zanzibar in East Africa to the Sulu Archipelago in the Philippines through Australian and Indonesian waters, 11–57 m depth. An unusual depth, 304 m, was recorded from off the Kai Islands by Griffin and Tranter (1986).