New record of the deep-sea crab Ethusina abyssicola from the Mar del Plata Canyon, Argentina

Abstract

Ethusina abyssicola Smith, 1884 (Decapoda, Ethusidae) belongs to Ethusidae, a family of small and deep-sea crabs adapted to carrying objects on their backs for camouflage. Ethusina abyssicola is the only species of that genus occurring in the West Atlantic, is distributed from New England, USA to Cape Frio, Brazil, and is one of the best adapted brachyuran crabs to inhabit deep water (up to 5046 m). We reported herein E. abyssicola in the deep and under-explored ‘Mar del Plata Canyon’ (38°01′S, 53°39′W), Argentina. The specimens were taken at 2934 m, which represents the greatest depth record for any brachyuran crab below 25°S in the southwestern Atlantic. Although E. abyssicola from the canyon mostly agree with previous descriptions, their outer orbital spines pointed forward and not outwards as in the original description. The significance of this difference is presently unknown and will require genetic analysis to be clarified.