Diagnosis of Arcturopsis Koehler, 1911 and redescription of A. giardi (Bonnier, 1896) (Crustacea, Isopoda, Arcturidae)

Rachael A. KING & Gary C. B. POORE

en Zoosystema 23 (3) - Pages 467-477

Published on 28 September 2001

The arcturid genus Arcturopsis Koehler, 1911 is rediagnosed and a key to its three species given. The type species, Arcturopsis giardi herein designated, is redescribed from new material. Arcturopsis is diagnosed as follows: body geniculate; margins of head and pereonite 1 separated by lateral incision; antenna 2 slender, with flagellum having a row of spines medially and ending in a claw; pereopod 1 with dactylus and unguis; pereopods 2 to 4 cylindrical and slender with paired closely spaced long setae, flexed between the carpus and propodus, dactylus absent; pereopods 5 to 7 with secondary unguis fused, smaller than the primary unguis; pleotelson with small lateral wing; oostegite 4 with posterior lobe; male more elongate than female, especially pereonite 4; pereonite 3 possessing a midventral appendage with complex apex; male pleopod 1 exopod laterally notched, with three long proximal setae on posterior face; male pleopod 2 with appendix masculina elongate, exceeding endopod, with two apical flagellate appendices. Post-marsupial developmental stages of Arcturopsis giardi are described. The species is distinguished from the A. rudis and A. senegalensis by having a female pereonite 4 without dorsal paired horns, longer than wide, and about seven times as long as pereonite 3, an apically blunt pleotelson, an antenna 2 flagellum of two articles plus a claw, and a male with a tridentate midventral appendage on pereonite 3.


Crustacea, Isopoda, Valvifera, Arcturidae, Arcturopsis, North Atlantic Ocean, diagnosis, redescription.

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