Recognition of Parapinnixidae Števčić, 2005, and Tetriasidae fam. nov. in Pinnotheroidea De Haan, 1833 (Crustacea: Brachyura: Thoracotremata) Author Tsang, Ling Ming 0000-0002-5029-5690 Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China. lmtsang @ cuhk. edu. hk; https: // orcid. org / 0000 - 0002 - 5029 - 5690 lmtsang@cuhk.edu.hk Author Naruse, Tohru 0000-0001-9212-5246 Tropical Biosphere Research Center, Iriomote Station, University of the Ryukyus, 870 Uehara, Taketomi, Okinawa 907 - 1541, Japan naruse @ lab. u-ryukyu. ac. jp; https: // orcid. org / 0000 - 0001 - 9212 - 5246 naruse@lab.u-ryukyu.ac.jp text Zootaxa 2023 2023-03-06 5249 5 540 558 http://dx.doi.org/10.11646/zootaxa.5249.5.2 journal article 10.11646/zootaxa.5249.5.2 1175-5326 7701343 949F2D17-F10C-4ED1-9580-2CB12BD65896 Key to the families in Pinnotheroidea De Haan, 1833 1. Pereopod 2 or pereopods 2 and 3 distinctly larger, more inflated and longer than pereopods 4 and 5. G1 long, slender, markedly bent mesially at proximal one-third to quarter....................................... Parapinnixidae Števčić, 2005 - Pereopod 2 shorter than, and not more inflated than other pereopods. G1 slender to rather stout, variously curved but not markedly bent at proximal one-third to quarter.................................................................. 2 2. Mxp3 palp articles (carpus, propodus, dactylus) all large, each article is about two-thirds length of merus; dactylus always present, extending to base of ischiomerus when palp folded...................................... Tetriasidae fam. nov. - Mxp3 palp articles (carpus, propodus, dactylus) may be developed but not always all large; dactylus present or absent, if present, extending at most to distal quarter of ischiomerus when palp folded.................. Pinnotheridae De Haan, 1833