Agononida (Machordom & Macpherson, 2004)

Cabezas, Patricia, Macpherson, Enrique & Machordom, Annie, 2009, Morphological and molecular description of new species of squat lobster (Crustacea: Decapoda: Galatheidae) from the Solomon and Fiji Islands (South-West Pacific), Zoological Journal of the Linnean Society 156 (3), pp. 465-493 : 487

AGONONIDA

None of our analyses recovered the monophyly of the genus, in line with the results of a previous study ( Machordom & Macpherson, 2004). In the present paper, we only inferred phylogenetic relationships among the newly described species and another five species of the genus. This results from the complexity of developing molecular analyses for the group, as we failed to amplify the COI gene for several species, making it difficult to establish relationships with a high level of confidence.

Despite this problem, our analyses were able to recover, with high support, the relationship between the new species, A. isabelensis sp. nov., and its sister group, A. similis , which is morphologically very similar. The two species can be easily differentiated according to the number of spines along the branchial margin of the carapace, and the number and size of spines on the basal article of the antennular peduncle, confirming the phylogenetic value of these characters. The relationship between this cluster and the species A. procera was also highly supported. The species Alainius crosnieri was also included in the analyses to check for the possibility of a polyphyletic origin of the group. Although all of the tree topologies located this species within the ingroup, this was not highly supported in any of the analyses. Further work is still required to clarify the apomorphic characters of the group, and its origin and diversification.