Parilia Wood-Mason, in Wood-Mason & Alcock 1891

Parilia Wood-Mason, in Wood-Mason & Alcock, 1891

Type species. Parilia alcocki Wood-Mason, in Wood-Mason & Alcock, 1891, subsequent designation under Article 68.2.1 [ICZN, 1999]; gender feminine).

Diagnosis. Carapace transversely subovate, ovate or longitudinally ovate; dorsal surface covered with small rounded granules or appearing smooth. Cardiac region with posteriorly directed spine; intestinal region with 2 spines. Exopod of third maxilliped very broad, much wider than ischium and merus, with outer margin strongly convex; coxa very wide, appearing almost semicircular, bracketing base of exopod. Suborbital region prominently compressed by expanded buccal cavity. Adult male chelipeds elongate, at least 3 times longer than carapace length; chela elongate, fingers distinctly shorter than palm, in large male individuals, fingers forming basal gape when closed. Male pleon with somites 1 and 2 free, somites 3–5 completely fused, somite 6 and telson free; surface of somite 6 smooth; telson triangular, subequal in length to somite 6. G1 elongate, slender, subdistal part bifurcated, longer subdistal lateral projection directed laterally inwards towards median of thoracic sternum; projections flared, forming distinct serrulate or denticulate flange. G2 distal segment as long as basal segment, with curved flagelliform tip.

1 Lee Kong Chian Natural History Museum, Faculty of Science, National University of Singapore, 2 Conservatory Drive, Singapore 117377, Republic of Singapore; Email: peterng@nus.edu.sg (* corresponding author)

2 Department of Aquatic Biology & Fisheries, University of Kerala, Kariavattom, Thiruvananthapuram – 695581, Kerala, India

© National University of Singapore

ISSN 2345-7600 (electronic) | ISSN 0217-2445 (print)

Remarks. Parilia Wood-Mason, in Wood-Mason & Alcock, 1891, is here restricted for three species, with P. tuberculata Sakai, 1961, referred to its own genus (see remarks for next genus).

Parilia alcocki and P. major are the two largest leucosioids known in the world, with adults exceeding 70 mm in carapace width. Alcock (1899: 29) recorded males of P. alcocki 56 mm in carapace width with a largest male in the present study measuring 70.6 mm (CASAU). For P. major, Chen & Sun (2002: 366) recorded a large male 60.1 mm in carapace width while in the present material, there is a male measuring 70.0 mm (ZRC 2001.552). Myropsis quinquespinosa Stimpson, 1871, from the western Atlantic coast has been reported to grow to carapace widths of 65.0 mm and 68.0 mm by Rathbun (1937: 166) and Williams (1984: 287), respectively.