Review of the pilumnid crab genus Lophoplax Tesch, 1918 from the western Pacific, with descriptions of two new species, and the clarification of the identity of Pseudocryptocoeloma parvus Ward, 1936 (Crustacea: Brachyura) Author Ng, Peter K. L. 0000-0001-5946-0608 Lee Kong Chian Natural History Museum, Faculty of Science, National University of Singapore, 2 Conservatory Drive, Singapore 117377, Republic of Singapore. peterng @ nus. edu. sg; https: // orcid. org / 0000 - 0001 - 5946 - 0608 peterng@nus.edu.sg Author Rahayu, Dwi Listyo 0000-0003-4342-9045 Research Center for Marine and Land Bioindustry, National Research and Innovation Agency, Dusun Teluk Kodek, Pemenang, Lombok Utara 83756, NTB, Indonesia. dwilistyo @ yahoo. com; https: // orcid. org / 0000 - 0003 - 4342 - 9045 dwilistyo@yahoo.com text Zootaxa 2023 2023-02-22 5244 5 428 454 http://dx.doi.org/10.11646/zootaxa.5244.5.2 journal article 54188 10.11646/zootaxa.5244.5.2 77045783-e389-456c-8405-402d9a928da1 1175-5326 7663766 B55396DA-15DB-4CDF-81FD-78686A0EC3A2 Lophoplax pannosa n. sp. ( Figs. 2H , 4D , 5F, L , 6F , 7F, L , 8D ) Type material . Holotype : ovigerous female (7.4 × 5.7 mm ) ( ZRC 2019.1190 ), station LD07, Turtle Bay , Vanuatu , 15°19.8′S 167°11.1′E , 1–3 m , coll. SANTO 2006 Expedition , 28 September 2007 Diagnosis of female . Carapace subquadrate ( Fig. 4D ); epigastric, protogastric, hepatic, cardiac and intestinal areolets glabrous, prominent, smooth; epigastric areolets transversely narrow,relatively longer, not fused with protogastric areolets ( Fig. 4D ); protogastric areolet relatively transversely narrower, obliquely positioned ( Fig. 4D ); cardiac areolet transverse in position ( Fig. 4D ); hepatic areolet prominent, more elongate, reaching to second anterolateral tooth ( Fig. 4D ); external orbital tooth triangular ( Fig. 4D ); tips of anterolateral teeth sharply pointed ( Fig. 4D ); junction between antero- and posterolateral margins with 2 low lobes, not swollen or tuberculiform ( Fig. 4D ); epistome relatively wider longitudinally ( Fig. 5F ); median lobe of posterior margin of the epistome relatively low with lateral margins gently concave ( Fig. 5F ). Third maxilliped with merus quadrate, ischium subrectangular ( Fig. 5L ). Dorsal and lateral surfaces of carpus of cheliped with 5 weakly defined areolets, deeply eroded ( Fig. 6F ); cheliped fingers not distinctly bent, pollex subparallel with the ventral margin of palm ( Fig. 7F ). P2–P5 relatively not elongate ( Figs. 2H , 7L ); outer surface of P3–P5 merus, carpus and propodus gently rugose ( Fig. 7L ). FIGURE 10. A–E, Lophoplax sculpta ( Stimpson, 1858 ) , neotype male (7.8 × 6.3 mm) (RUMF-ZC-8127), Okinawa; F–J, L. sordida n. sp. , holotype male (8.2 × 6.5 mm) (MZB Cru 5449), Lombok. A, B, pleon; B, G, left G1 (ventral view); C, H, distal part of left G1 (ventral view); D, I, left G1 (dorsal view); E, J, left G2. Scales: A, F = 1.0 mm; B, E, G, J = 0.5 mm; C, D, H, I = 0.2 mm. Colour in life . Not known. Etymology . The name is derived from the Latin “pannosus” for scruffy or unkempt, alluding to the general appearance of the species, even after cleaning. Remarks . Lophoplax pannosa n. sp. differs from L. scuplta in that the epigastric areolet is transversely narrower and longer ( Fig. 4D ) (versus relatively wider and shorter; Fig. 3A–C ); the protogastric areolet is relatively transversely narrower and obliquely positioned ( Fig. 4D ) (versus transversely wider and subparallel in position; Fig. 3A–C ); the cardiac areolet is obliquely positioned ( Fig. 4D ) (versus clearly transverse in position; Fig. 3A–C ); the hepatic areolet is proportionately longer, reaching to the beginning of the second anterolateral tooth ( Fig. 4D ) (versus shorter, reaching only to the base of the first tooth; Fig. 3A–C ); the junction between the antero- and posterolateral margins is demarcated by two low lobes but neither swollen or tuberculiform ( Fig. 4D ) (versus junction with two large rounded to subtruncate tubercles with the tips rounded to flattened, often with median depression; Figs. 3A–C , 9A ); the median lobe of the posterior margin of the epistome is relatively low with the lateral margins gently concave ( Fig. 5F ) (versus median lobe is more salient with the lateral margins deeply concave; Fig. 5A, B ); and the dorsal and outer surfaces of the carpus of the cheliped are covered with five weakly defined areolets which are deeply eroded ( Fig. 6F ) (versus with four distinct smooth areolets; Fig. 6A, B ). No male specimens are available. Habitat . The type was collected from shallow waters by diving ( 1–3 m depth) in a reef area with some seagrass beds nearby. Distribution . Known only from Vanuatu thus far.