Charybdis (Charybdis) jaubertensis Rathbun, 1924

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 : 62

Charybdis (Charybdis) jaubertensis Rathbun, 1924

( Fig. 13F)

Material examined. RV Hakuhō Maru KH-72-1 cruise, sta. 29, 1Ə ( CB 11.3×CL 8.9 mm), NSMT-Cr 30731.

Remarks. The male specimen examined is without doubt referable to Charybdis (Charyb- dis) having the carapace with six anterolateral teeth of nearly equal size and the round junction of the posterior and posterolateral carapace margins, but as in Fig. 13F, the subquadrate carapace is seemingly close to some Thalamita species. There are no distinct ridges or granular patches behind the metagastric and epibranchial ridges. The front is prominently six-lobed; the median lobes are separated by a narrow but distinct deep slit, and subtruncated, with weakly rounded distal margin; the submedian lobe is about 1.5 times as wide as the median lobe, as high as, or only slightly shorter than the median lobe, with a subtruncated, or weakly convex distal margin; the distal margin of the submedian lobe is weakly inclined toward the base of the median lobe; the submedian lobe is separated from the median lobe by a notch and from the lateral lobe by a wide slit; the lateral lobe is as wide as the median lobe at the base, triangular, with an obtuse tip; the tip of the lateral lobe exceeds the inner supraorbital lobe, but does not reach as far as the distal margin of the submedian lobe. The orbit is large, and its diameter is as long as half the frontal margin; a narrow slit is distinct on the inner part of the supraorbital margin. The carapace anterolateral margin is only weakly convex and armed with six sharp-tipped teeth that are nearly subequal or the first and third may possi- bly larger than the others, and the last is slightly smaller than the preceding tooth; in the specimen examined the right first tooth is broken at the tip, but the left tooth is subtruncated along the outer margin, with sharp tip.

The original description of Charybdis (Cha- rybdis) yaldwyni by Rees and Stephenson (1966) based on a large series, included comparison with the holotype of C. jaubertensis Rathbun, 1924 , and the observation that C. jaubertensis recorded by Stephenson et al. (1957) is referred to C. yaldwyni . Many differences between both species are summarized in the table by Rees and Stephenson (1966), but most of them are subtle qualitative distinctions. These distinctions are not always clearly applicable to the specimen at hand, but is closer to C. jaubertensis than C. yaldwyni , mainly based on the frontal lobes and carapace anterolateral armature.

Distribution. According to Rees and Stephenson (1966), the distribution is in Australian waters from Shark Bay, Western Australia to Moreton Bay, Queensland, with its distribution being nearly sympatric with C. yaldwyni . The recorded bathymetric range is from 10 to 31 m.