Cladistic analyzis of the Family Marginellidae (Mollusca, Gastropoda) based on comparative morphology / Análise cladística da família Marginellidae (Mollusca, Gastropoda) baseada em morfologia comparada

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

In the present study a cladistic analysis of the family Marginellidae is carried out. A sample consiting of 18 marginellid species and 4 muricoideans, as out group, was examined. Dissection and comparative morphological analysis of this sample rendered 93 characters, 12 conchological characters and 81 derived from the soft parts morphology. The matrix analysis resulted in four equally parsimonious trees (237 steps, IC: 0,55, IR: 0,79). A successive weighting analysis was then carried out that resulted in three equally parsimonious trees (982 steps, IC: 0,75, IR: 0,9), and their strict consesus was chosen for the discussions. From the resulting three we conclude that: Marginellidae is a monophyletic group suported by 17 syanpomorphies. Cystiscidae is distinct from Marginellidae, but share many homoplastic characters with it. Volutidae is sister group to Marginellidae. Autroginellini as defined by COOVERT &COOVERT (1995) is supported by a in-group plesiomorphy, suggesting it is not a monophyletic grouping. The loss of the valve of Leiblein occurred independently in Prunini and Marginellini. Prunini is a is a monophyletic group defined by the esophageal pouch, and several anatomical and conchological modifications that occurred due to the lateralization of the animal. Prunum is a monophyletic group defined by the posterior fusion of the odontophoric cartilage. Leptegouana is a monophyletic group defined by the shortening of m8 and renal cavity. Marginellini is a monophyletic group defined by the loss of the odontophore and the oral tube. Marginella is a monophyletic genus diagnosed by the opening of the gland of Leiblein right infront the nerve ring, by the vestigial valve of Leiblein, and but the muscular proboscis. Eratoidea is a is a monophyletic genus diagnosed by the elongated anal siphon, by the presence of an ejaculatory papilla on the penis, by the opening of the gland of Leiblein close to the mouth, and by tubular salivary glands located inside the proboscis.

ASSUNTO(S)

filogenia morfologia marginellidae marginellidae mollusca phillgenia morphology mollusca

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