Revision of the intertidal and semiterrestrial crab genera Chiromantes Gistel, 1848, and Pseudosesarma Serène & Soh, 1970 (Crustacea: Brachyura: Sesarmidae), using morphology and molecular phylogenetics, with the establishment of nine new genera and two new species Author Schubart, Christoph D. Zoology & Evolution, University of Regensburg, 93040 Regensburg, Germany christoph.schubart@ur.de Author Ng, Peter K. L. 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 text Raffles Bulletin of Zoology 2020 2020-12-23 68 891 994 journal article 55667 10.26107/RBZ-2020-0097 6cb155ce-8b9f-48ce-8e6c-b0dc00f8b1cc 2345-7600 5351295 815E4670-B063-4FD8-B31E-3AD89B3A7942 Migmarma lorentzi , new species ( Figs. 50–52 ) Material examined . Holotype : male (15.8 × 14.0 mm) ( NMBA 625IIa ), Noord River ( = present day Lorentz River ), New Guinea , ca. 4°15′S 138°40′E , coll. Lorentz Expedition 1909 (donated Zoological Museum Amsterdam, 1920). Paratype : 1 female (13.4 × 11.8 mm ) ( NMBA 625 IIa), same data as holotype . Diagnosis . Carapace squarish, slightly longer than wide; dorsal carapace surface smooth, glabrous; epibranchial tooth distinct, separated by deep notch; posterolateral margins subparallel; outer surface of chela gently rugose, smooth flattened granules, outer surface gently convex, not flat, ventral margin of palm gently concave; suture between male thoracic sternites 3 and 4 distinct; ambulatory merus short, broad; male pleon subrectangular, telson rounded, slightly sunken into distal margin of somite 6; G1 slender, gently curved, chitinous distal part long, tapering, relatively slender, subspatuliform, tip appears bifurcated. Etymology . The species is named after Hendrikus Albertus Lorentz, the Dutch explorer for whom its type locality river is also named. Remarks . In having the male telson only slightly sunken into somite 6, Migmarma lorentzi , new species , superficially resembles species of Bresedium , notably B. laevimanum , but can easily be separated by the male telson being rounded and the pleonal somite 6 less broad ( Fig. 50E ) (versus telson more elongate and somite 6 is wider and more rectangular in shape in B. laevimanum ; Figs. 31F–H , 42A ); and the G1 is also proportionately stouter and the tip of the chitinous distal part is tapering and sharp ( Figs. 50F–K , 51A–E ) (versus G1 proportionately more slender and the tip of the chitinous distal part is flared in B. laevimanum ; Fig. 42B–E ).