Genus Xenosinelobus n. gen. Diagnosis. Four free pleonites; pleonites 1 and 2 each with a complete dorso-transverse row of feather setae; pleonite 5 fused with pleotelson to form an anterior bulge. Antennule terminal article with two or three aesthetascs. Antenna article-5 as short as article-6. Labium outer lobe without terminal process. Left mandible lacinia mobilis with one seta at base; right mandible similar but with a smaller lacinia mobilis. Maxillule palp with three long setae. Epignath with long terminal seta. Pereopods scattered with very fine setae. Pereopod 1 coxa without anterior bulge, but with one spiniform seta; propodus with pinnate inner seta; dactylus with simple inner seta, together with unguis slender and almost straight. Pereopods 2 and 3 dactylus and unguis not fused but claw-like. Pereopod 6 propodus distal margin with row of three flattened denticulate and one setulose setae. Pleopod basis outer and inner margins each with one seta; endopod inner margin with two or three feather setae. Uropod with three articles, and the final article much longer than preceding article. Sexual dimorphism weak, males having longer antennule, longer fourth article of antenna and small denticles on cutting edge of cheliped dactylus. Remarks. Within the subfamily, Xenosinelobus n. gen. is more closely affiliated to Sinelobus as compared to Parasinelobus by the smaller body size, absence of setal tuft on antennal articles-2 and -4, the lower number of spiniform setae on the carpus of pereopods 2–6, and the lower number of setae on the maxillule palp and pleopod basal article, exopod and endopod (Table 1). Etymology. The genus name refers to its morphological similarity to Sinelobus Sieg, 1980 and to the unusual characteristics that distinguish this species from other genera in the same subfamily, from the Greek “xenos” meaning “stranger”. Gender: masculine. Type species. Xenosinelobus balanocolus n. sp., by original designation.

Published as part of Chim, C. K. & Tong, Samantha J. W., 2019, Xenosinelobus balanocolus, a new tanaidid genus and species (Crustacea: Peracarida: Tanaidacea) from barnacles on intertidal rocky shores and seawalls in the Singapore Strait, pp. 413-427 in Zootaxa 4629 (3) on pages 414-415, DOI: 10.11646/zootaxa.4629.3.9, http://zenodo.org/record/3271079