First report of the king crab Neolithodes asperrimus Barnard, 1947 (Crustacea: Lithodidae) from the Brazilian Amazon continental slope

The family Lithodidae Samouelle, 1819 is composed of deep-sea crabs that inhabit continental and insular slopes, cold seeps, hydrothermal vents and abyssal plains. In the Atlantic Ocean, five species of the genus Neolithodes A. Milne-Edwards & Bouvier, 1894 have been reported, of which only two species were recorded from Brazilian waters, with all occurrences restricted to northeastern and southeastern regions. Herein we report a new occurrence of the lithodid Neolithodes asperrimus Barnard, 1947, from the Brazilian Amazon continental slope, highlighting the morphological comparisons with the closely related species, Neolithodes agassizii (Smith, 1882), based on data available in the literature.

The male specimen of N. asperrimus was collected during surveys conducted under the ReviZEE Program [Assessment of the Sustainable Potential of Living Resources of the Exclusive Economic Zone (Northern Brazil)], using a commercial fishing net at depths of up to 1100 m, between 1996 and 2001. Our specimen of N. asperrimus was morphologically compared to N. agassizii from the literature, and we observed that both species share several morphological characters.

We consider only the proportion of merus length relative to carapace length and the spinulation of the walking legs to be useful in separating these two species. Additionally, the presence of N. asperrimus in the Amazon continental slope increases its geographic distribution, corresponding to the second observation of this species in Brazilian deep waters. This new record is an important contribution to the understanding of distributional patterns of lithodid species in Brazil and to the increase in biodiversity data of crustaceans from the Brazilian Amazon region.