On the species of Abyssianira Menzies, 1956 (Isopoda: Asellota: Paramunnidae) from the South-West Atlantic Ocean.

DOTI, B.L.; ROCCATAGLIATA, D.; REHM, P.

Glasgow

Congreso; Sixth International Crustacean Congress, ICC6; 2005

University of Glasgow

The genus ABYSSIANIRA Menzies, 1956 includes two Atlantic species found at abyssal depths (A. DENTIFRONS Menzies, 1956; A. ARGENTENENSIS Menzies, 1962) and two Australian species from upper to mid-bathyal depths (A. BATHYALIS Just, 1990; A. TASMANIENSIS Just, 1990). In the present contribution the Atlantic species of ABYSSIANIRA are revised. The material studied includes the holotypes of the two previously described Atlantic species (deposited in the AMNH), some additional specimens collected by the WHOI (deposited in the Australian Museum, Sydney), and a sample taken by the DINARA (Dirección Nacional de Recursos Acuáticos, Montevideo). In the present study A. DENTIFRONS and A. ARGENTENENSIS are redescribed based on type material, and two new species from off Argentina and off Brazil are described, raising the number of species known for this genus to six. The four Atlantic species treated in this study are easily distinguish from each other mainly by size and shape of the serrated frontal plate and the eyestalks. A. ARGENTENENSIS is herein reported at 129 m depth, being this the first record of this genus in shallow waters. None of the species of the genus ABYSSIANIRA has ocelli. This fact suggests a deep-sea origin for this genus, and that A. ARGENTENENSIS subsequently invaded the outer margin of the continental shelf.