Meeting Abstract

S8-1.6  Sunday, Jan. 6  Towards an Evolutionary Classification of Mycalina and Latrunculina (Poecilosclerida) HAJDU, E.*; LôBO-HAJDU, G.; COSME, B.; DE PAULA, T.; REDMOND, N.E.; COLLINS, A.G.; THACKER, R.W.; Universidade Federal do Rio de Janeiro; Universidade do Estado do Rio de Janeiro; Universidade do Estado do Rio de Janeiro; Universidade do Estado do Rio de Janeiro; Smithsonian Institution; Smithsonian Institution; University of Alabama, Birmingham

A cladistic assessment of familial relationships on the basis of morphological characters obtained low support for the monophyly of Mycalina, with Isodictyidae and Desmacellidae included (Bayesian Analysis - BA), or left out of it (Maximum Parsimony – MP; and Neighbor Joining - NJ). BA retrieved no clades within the suborder, while MP and NJ shared only slight congruence in assigning Hamacanthidae and Merliidae to the same clade, a trichotomy with Podospongiidae in NJ. No morphological cladistic study of Latrunculina affinities has been carried this far. Mycalina and Latrunculina are rather poorly represented in molecular studies. Recent highlights are the non-Mycaline affinity of the polyphyletic Desmacellidae (28S) and Podospongiidae (Diacarnus, 28S & COI), as well as the confirmation of Abyssocladia’s assignment to Cladorhizidae (28S & COI). The PorToL project 18S tree confirms the non-Mycaline affinity of both former families, and suggests that Esperiopsidae (Amphilectus) may be a sister of Isodictyidae (Isodictya), both being sister of Podospongiidae (Diacarnus, Negombata, Neopodospongia). This project also suggests that Desmacella lampra may actually belong in Mycale, that Mycalidae (Mycale) and Guitarridae (Guitarra) may be sister groups, and that Latrunculina (Latrunculia, Tsitsikamma) may be monophyletic and belong in the Poecilosclerida. Important taxa of Mycalina and Latrunculina still missing in molecular trees are Hamacanthidae and Merliidae, further genera of Esperiopsidae, Guitarridae and Latrunculiidae, and additional subgenera of Mycale. It is also important to add Cladorhizidae into more comprehensive trees.