Deeper diversity exploration: New Typhlotanaidae (Crustacea: Tanaidacea) from the Kuril-Kamchatka Trench area

Abstract

Typhlotanaidae Sieg, 1984, is one of the most diverse Tanaidacea families from deep-sea waters. Its diversity is underestimated, and evolutionary relationships within the family remain mostly unknown. Deep-sea typhlotanaids collected from 23 sites across the Kuril-Kamchatka Trench and nearby waters were studied using an integrative taxonomy approach, combining morphological and genetic data (i.e., the mitochondrial subunit I of the cytochrome oxidase (COI) and the 18S rDNA nuclear gene). One new species of Typhlamia and two new species belonging to two new genera are described, significantly increasing the known diversity of typhlotanaids from the NW Pacific. The molecular phylogeny obtained, despite being preliminary results, was congruent with morphological data and supports the monophyly of different groups such as the ‘short-bodied’ forms (represented by Ty. cornutus and Ty. eximius) or the ‘collar’ forms (e.g., Ty. variabilis and Torquella). Molecular data confirm the non-monophyly of Typhlotanais species. Finally, the new typhlotanaid taxa seem to have distinct bathymetric distribution and ecological requirements, but further data on environmental factors and species abundances are still needed.

Mislabeling and nomenclatorial confusion of Typhlotanais sandersi Kudinova-Pasternak, 1985 (Crustacea: Tanaidacea) and establishment of a new genus

“…The recent discovery of a new species of Typhlamia from the Kuril-Kamchatka Trench ( Gellert, Palero & Błażewicz, 2022 ) and the re-evaluation of Typhlotanais sp. A from Błażewicz-Paszkowycz et al (2014) uncovered significant genetic and morphological differences between Typhlamia and the morphogroup of species including the original holotype description and drawings of Typhlotanais sandersi Kudinova-Pasternak, 1985 .…”

“…Data on the morphology and morphometry of the ‘long-bodied’ typhlotanaids (body length ≥8.0 L:W) with rounded pereonites were collected from Bird (2004) , Błażewicz-Paszkowycz (2007a) , Błażewicz-Paszkowycz, Bamber & Jóźwiak (2013) , Błażewicz-Paszkowycz et al (2014) , Gellert, Palero & Błażewicz (2022) , Hansen (1913) , Kudinova-Pasternak (1966 , 1985 , 1989 , 1990 ), Kudinova-Pasternak & Pasternak (1978) , Lang (1971) , Larsen (2011) , Larsen, Błażewicz-Paszkowycz & Cunha (2006) , Larsen & Shimomura (2007) , Sars (1882 , 1899) . The data gathered are shown in Table 1 .…”

“…All sequences used in the molecular studies are from GenBank. Sequences from Gellert, Palero & Błażewicz (2022) were obtained from the University of Lodz Tanaidacea collection (GenBank accession numbers: - for COI and - for 18S rDNA; see Table 2 ). The molecular tree used in the current study come from publication by Gellert, Palero & Błażewicz (2022) .…”

“…Morphological differences between the type species and the other putative Typhlotanais species were so apparent that, during the second half of the 20th century, four genera ( Meromonakantha Sieg, 1986a , Paratyphlotanais Kudinova-Pasternak & Pasternak, 1978 , Peraeospinosus Sieg, 1986a , and Typhlotanoides Sieg, 1983 ) and the family Typhlotanaidae Sieg, 1984 itself were erected ( Kudinova-Pasternak & Pasternak, 1978 ; Sieg, 1983 , 1984 , 1986a ). Typhlotanais currently includes 53 species (44% of 123 typhlotanaid species known) and it is the most speciose out of 16 typhlotanaid genera ( Gellert, Palero & Błażewicz, 2022 ; WoRMS, 2022 ; Lubinevsky, Tom & Bird, 2022 ).…”

“…After a new species of Typhlamia Błażewicz-Paszkowycz, 2007a was collected from Northwest Pacific waters ( Gellert, Palero & Błażewicz, 2022 ), detailed morphological analysis and literature revision has revealed that the original description of Ty. sandersi by Kudinova-Pasternak (1985) differed from the redescription made by Błażewicz-Paszkowycz (2007a) .…”