Pseudolambrus confragosus ( Calman, 1900 )

Padate, Vinay P., Cubelio, Sherine Sonia & Takeda, Masatsune, 2024, First records of some coral reef-associated brachyuran crabs from the Nicobar archipelago, India, Zootaxa 5486 (4), pp. 476-498 : 483-485

publication ID	https://doi.org/ 10.11646/zootaxa.5486.4.2
publication LSID	lsid:zoobank.org:pub:29F6FDC3-3166-4309-A7B2-1582358AA1FD
DOI	https://doi.org/10.5281/zenodo.13228763
persistent identifier	https://treatment.plazi.org/id/03EA8791-7F2C-FF81-FF79-FC42B5A1D4EC
treatment provided by	Plazi
scientific name	Pseudolambrus confragosus ( Calman, 1900 )
status

Treatment

Pseudolambrus confragosus ( Calman, 1900) View in CoL

( Figs. 2C View FIGURE 2 , 5A–G View FIGURE 5 , 10D–H View FIGURE 10 )

Lambrus (Parthenolambrus) confragosus Calman, 1900: 42 View in CoL , pl. 3 figs. 27, 28 (type locality: Torres Strait, Australia).— Flipse 1930: 48 (identification key), 87 (index).

Parthenope (Parthenolambrus) calappoides View in CoL .— Rathbun 1906: 832 (list), 886, pl. 15 fig. 6 (in part).

Lambrus confragosus View in CoL — Grant & McCulloch 1906: 32.

Parthenope (Pseudolambrus) confragosus — Serène 1968: 61 (list).

Pseudolambrus confragosus View in CoL —Davie 2002: 389 (list).— Tan 2004: 367, figs. 96G, 101.— Ng et al. 2008: 131 (list).

Material examined. 1 male (22.2 × 18.0 mm) (IO/SS/BRC/00323), FORVSS stn. 38818, south of Great Nicobar Island , Nicobars, India, 6.65°N, 93.83°E, 56 m depth, chain bag dredge, coll. V.P. Padate, 16 August 2019 GoogleMaps .

Description. Carapace subtriangular, 1.2 times as wide as long, widest at posterolateral angle, dorsal surface irregularly tuberculate ( Figs. 2C View FIGURE 2 , 5A View FIGURE 5 ); hepatic region inflated, with strongly projected, medially angled margin; gastric region with a tall median, distally tapering tubercle ( Fig. 5B View FIGURE 5 ); hepatobranchial and gastrobranchial notches deep; cardiac region with anterior median tubercle 2.0 times as high as posterior median tubercle. Frontal margin relatively long, deflexed, ventral surface with 2 depressions ( Fig. 5C View FIGURE 5 ); lateral margins distinctly granular, diverging anteriorly, subparallel posteriorly; posterolateral corners with blunt spines; posterior margin with granulate tubercles dorsally.

Antennules folding obliquely; basal antennal article short, article 4 margin with 2 mesial and 1 lateral teeth ( Fig. 5C View FIGURE 5 ); epistome well-developed, posterior margin elevated, median portion with two rounded protuberances ( Fig. 5C View FIGURE 5 ); mxp3 merus subquadrate, half as long as ischium, with median depression and irregularly arranged granules ( Fig. 5D View FIGURE 5 ).

Chelipeds subequal, 1.7 times CL, merus outer margin with large teeth, inner margin with 3 large triangular teeth ( Fig. 2C View FIGURE 2 ); carpus with dentate carinae on inner and outer margins; palm with large crested lobe at midlength of outer margin, dactylus half as long as palm, with toothed crest along proximal half ( Fig. 5E View FIGURE 5 ). Pereopods 2–5 shorter than chelipeds, densely tomentose, outer margins of meri, carpi and propodi armed with larger teeth compared with inner margins ( Fig. 5F View FIGURE 5 ).

Male pleon elongate sub-triangular, somites 3–5 fused, somite 6 longest, ventral surfaces of somites 3–5 with a transverse row of 4 granules each, that of somite 6 with median granule ( Fig. 5G View FIGURE 5 ); telson bluntly triangular, twothirds as long as wide ( Fig. 5G View FIGURE 5 ). G1 stout, nearly straight ( Fig. 10D, G View FIGURE 10 ), distal portion blunt with subdistal ventral spinose patch, spines on mesial margin extending to proximal half ( Fig. 10E–F View FIGURE 10 ). G2 shorter than G1 ( Fig. 10H View FIGURE 10 ).

Colouration. Fresh specimen: Carapace brick red, chelipeds brick red with whitish bands on proximal half of merus and midlength of palm, fingers whitish with brown tips, pereopods whitish with brick red patch on meri ( Fig. 2C View FIGURE 2 ).

Biology. The present specimen was collected from rocky substrate in the vicinity of crinoids, at 56 m depth. Known to inhabit coral and sponge colonies, and coarse calcareous sand in reefs ( Laurie 1906; Tan 2004) at depths from 18–500 m ( Tan 2004).

Remarks. Calman (1900) described Lambrus (Parthenolambrus) confragosus from a female collected from Torres Strait, Australia, on the basis of a highly rugged carapace, compressed dentiform hepatic prominences, and the flattened lamelliform lobes on the outer margin of the cheliped palm. According to Tan (2004), Pseudolambrus confragosus resembles P. tarpeius (Adams & White, 1849) in the carapace armed with irregular, granular tubercles, and the presence of granular tubercles on the dorsal surface of carapace posterior margin. However, it differs from P. tarpeius in having a narrower hepatic region, relatively more inflated epibranchial region, and the presence of a lamelliform lobe on the outer surface of cheliped palm ( Fig. 5A, E View FIGURE 5 ) (versus broader hepatic region, relatively less inflated epibranchial region, and the absence of a lamelliform lobe on the outer surface of cheliped palm in P. tarpeius ; see Tan 2004: fig. 104A). The Indian specimen conforms to the description of the holotype ( Calman 1900) as well as subsequent descriptions ( Laurie 1906; Rathbun 1906; Tan 2004) in the distinctly tubercular and rugged surface of the carapace and chelipeds. However, the ornamentation on the G1 differs from the G1 of a male specimen from the Balicasag Island, Philippines in the presence of a subdistal spiny patch on the ventral surface ( Fig. 10D, E View FIGURE 10 ) (versus G1 with smooth ventral surface in the Philippine specimen; cf. Tan 2004: fig. 96G, H).

Geographical distribution. Torres Straits ( Calman 1900), Sri Lanka ( Laurie 1906), Australia ( Grant & McCulloch 1906) and Hawaii ( Rathbun 1906), Seychelles, Mauritius, Gulf of Aden, the Philippines and New Caledonia ( Tan 2004); and Nicobars, India (present study). The present observation is the first record from Indian waters.

Kingdom	Animalia
Phylum	Arthropoda
Class	Malacostraca
Order	Decapoda
Family	Parthenopidae
Genus	Pseudolambrus