Scavenging amphipods of the Angolan deep-sea habitat, with a focus on Abyssorchomene distinctus (Birstein and Vinogradov, 1960) (Amphipoda: Lysianassoidea)

Grant A. Duffy, Tammy Horton, Stephen F. Lawler
2016 Journal of Crustacean Biology  
18 Owing to its vast natural resources and the influence of the Congo River and 19 associated submarine canyon, the Angolan continental margin is of both 20 socioeconomic and ecological interest. The deep-sea ecosystems of the region are, 21 however, understudied, and much of the deep-sea fauna remains undescribed. Here, 22 we document the scavenging amphipods of the the Angolan deep-sea habitat, which 23 provides valuable new insight into the ecology of Angolan deep-sea scavengers. This 24 can
more » ... engers. This 24 can be used as an ecological baseline, against which resource-extraction impacts can 25 be measured. 7 996 scavenging amphipods, representing 10 species, were identified. 26 At least four species were new to science. The relatively low scavenger diversity of 27 the region, combined with the large sample sizes, may be indicative of abundant food-28 falls in the region due to the presence of the submarine canyon system. 29 The dominant species across all samples, Abyssorchomene distinctus (Birstein 30 & Vinogradov, 1955), was the focus of a population-level study, which was used to 31 describe the population structure of this species and identify species traits. Of the 826 32 A. distinctus dissected and measured, 533 were unsexed juveniles, 149 were male, and 33 144 were female. Females were significantly larger than males, which is indicative of 34 non-mate-guarding pre-copulatory behaviour, but had significantly shorter antennae, 35 which may indicate that males use chemical cues during mate-searching. Two, three, 36 and five discrete size-based cohorts were identified for juveniles, males, and females 37 respectively. No ovigerous females were caught but brood size of A. distinctus was 38 estimated to be 10 -38 offspring based on ovary contents. 39 40
doi:10.1163/1937240x-00002448 fatcat:l7f7cdvbbvdlxibjwydou6npui