New insights gained from museum collections: new deep-sea species of Typhlotanais (Tanaidacea, Typhlotanaidae) from Brazil Author Segadilha, Juliana L. E9DE1623-8562-49C8-9146-76EF9D8BEC88 Laboratório de Carcinologia, Departamento de Invertebrados, Museu Nacional / Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, 20940 - 040, Rio de Janeiro, RJ, Brazil. Programa de Pós-graduação em Ciências Biológicas (Zoologia) do Museu Nacional. julianasegadilha@gmail.com Author Serejo, Cristiana S. A86225AE-51C8-4D01-9D3E-60FB5B1FE85C Laboratório de Carcinologia, Departamento de Invertebrados, Museu Nacional / Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, 20940 - 040, Rio de Janeiro, RJ, Brazil. Programa de Pós-graduação em Ciências Biológicas (Zoologia) do Museu Nacional. csserejo@acd.ufrj.br text European Journal of Taxonomy 2022 2022-05-20 820 1 54 journal article 56295 10.5852/ejt.2022.820.1791 093b6984-c0e6-4c86-ab69-39d669316f3f 2118-9773 6574383 D317A201-A0CA-4371-81A3-A244E727F29F Genus Typhlotanais Sars, 1882 Type species Typhlotanais aequiremis (Lilljeborg, 1864) . Diagnosis See Błażewicz-Paszkowycz (2007) . Remarks Błażewicz-Paszkowycz (2007) revised the family in a large monograph, which described five new genera and 13 new species, as well as grouped species sharing a set of unique characters in seven ‘morpho-groups’ within Typhlotanais , e.g. ‘ greenwichensis ’ group, ‘mixtus’ group, ‘ spinicauda ’ group, ‘ cornutus ’ group, ‘plicatus’ group, ‘eximius’ group, and ‘ trispinosus ’ group. Characters of each ‘morpho-group’ are mentioned when comparing to new species described herein. It is assumed that the ‘morpho-groups’ may constitute new genera, but this must be further analyzed with a phylogenetic study. However, some typhlotanaids were neither classified under any previously established genera nor included in the morpho-groups created. According to Błażewicz-Paszkowycz (2007) , Typhlotanais sensu stricto comprises only the type species T. aequiremis (Lilljeborg, 1864) and all other species temporarily classified as Typhlotanais sensu lato , showing large variation in characters as the pereonite-1 ratio (length to width), the number of setae on cheliped carpus dorsal margin setation, the form of mandible molar process form, and the shape of pereopods 1–3 basis shape. Typhlotanais is the most speciose genus of the family with 48 described species and a recent unpublished morphological phylogeny encompassing the family Typhlotanaidae suggests it is a polyphyletic group ( Segadilha 2019 ) that badly needs a revision.