Haimormus shimojiensis, a new genus and species of Pseudozeuxidae (Crustacea: Tanaidacea) from a submarine limestone cave in Northwestern Pacific

Abstract

We establish a new pseudozeuxid genus Haimormus gen. nov. based on a new species Haimormus shimojiensis sp. nov. which was collected from a submarine limestone cave with the entrance at 35 m depth, in the Northwestern Pacific Ocean. H. shimojiensis differs from the other confamilial members, Pseudozeuxo belizensis Sieg, 1982 and Charbeitanais spongicola Bamber & Bird, 1997, in having the pleonite 1 without the pleopod, the pereopods 2 and 3 propodus with a ventral spiniform seta, and the pereopods 4–6 propodus with one long and two short dorsodistal setae. A key to females of species of Pseudozeuxidae is presented. This is the first tanaidacean report from submarine caves around Japan.

First records of Pseudozeuxidae and Metapseudinae (Metapseudidae) (Crustacea, Tanaidacea) in Southwestern Atlantic, with descriptions of two new species

“…The apseudomorphs are predominantly a shallow-water group and the family Metapseudidae occurs mainly in the continental shelf <200 m (Błażewicz-Paszkowycz et al 2012). Species of Pseudozeuxidae are typical from coastal water (to 18 m) (Sieg 1982;Bamber and Bird 1997;Kakui and Fujita 2018). Currently, there are regions whose shallow-water tanaidacean faunas are still under-researched.…”

“…The family Pseudozeuxidae is characterized by reduced pleon with pleonites narrower than pereonite-6 in dorsal view and pleonites 1-5 combined shorter than pereonite-6 (Sieg 1982;Bamber and Bird 1997;Kakui and Fujita 2018). There are only three monotypic genera in this family: Charbeitanais Bamber & Bird, 1997;Haimormus Kakui & Fujita, 2018 and Pseudozeuxo.…”

“…There are only three monotypic genera in this family: Charbeitanais Bamber & Bird, 1997;Haimormus Kakui & Fujita, 2018 and Pseudozeuxo. Nevertheless, Haimormus is easily distinguished due to the absence of pleopods while Charbeitanais and Pseudozeuxo present only pleopod-1 (Sieg 1982;Bamber and Bird 1997;Kakui and Fujita 2018). Pseudozeuxo differs from Charbeitanais by (1) antennule with subterminal aesthetasc; (2) antenna article-2 with two setae; (3) maxilliped endites with gustatory cusps only on distal margin; (4) cheliped carpus with three ventral setae; (5) pereopods 2-3 propodus with two ventral setae and (6) uropod endopod two-articled (Sieg 1982;Bamber and Bird 1997 Diagnosis.…”

“…It is distinguished from P. belizensis by (1) pereopods 1-3 coxa with long seta about as half as long as basis; (2) pereopods 2-3 carpus with only seta ventrodistally (P. belizensis has seta and spine); (3) pereopods 4-6 propodus with two spines and one seta ventrally; (4) uropod endopod article-2 0.8 times as long as article-1 (P. belizensis with article-2 small, about 0.4 times as long as article-1) and exopod one-articled (P. belizensis is two-articled). Charbeitanais and Haimormus are recorded from the Pacific Ocean (Hong Kong and Japan, respectively; Bamber and Bird 1997; Kakui and Fujita 2018) and Pseudozeuxo is restricted to the Atlantic Ocean, being now recorded from the Southwestern Atlantic, besides the Caribbean Sea (Belize; Sieg 1982). Pseudozeuxo belizensis is a shallow water species (0.5-3 m depth) occurring at upper stratum of middle intertidal zone on coral reef (Sieg 1982), a generally similar habitat to that of Pseudozeuxo fischeri.…”

Paradoxapseudes shimojiensissp. nov. (Crustacea: Tanaidacea: Apseudidae) from a submarine limestone cave in Japan, with notes on its chelipedal morphology and sexual system

“…Since the pioneering work by Băcescu (1980), 17 species of tanaidaceans in genera have been reported from submarine caves (Kakui and Fujita 2018;Kakui et al 2019), although most of these species are not restricted to caves (García-Herrero et al 2019).…”