Cladistic analysis of the Conulariina Miller and gurley 1896 (Cnidaria, Scyphozoa; Vendian/Triassic)

Author(s)

Juliana de Moraes Leme

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Geociências (IG/BT)
• Defense date: 2006-03-06

Examining board members

Marcello Guimarães Simões; Luiz Eduardo Anelli; Vera Maria Medina da Fonseca; Antonio Carlos Marques; Setembrino Petri

• Advisor: Marcello Guimarães Simões

Abstract

The Conulariidae (Cnidaria) cladistic analysis is here presented being founded on the hypothesis that the classical suprageneric groups (families and subfamilies) recognized in the ?Treatise on Invertebrate Paleontology? (TIP), are not phylogenetically valid. The study included the revision of fossil material deposited in Brazilian and international scientific collections, having the following objectives (1) the conulariid cladistic analysis to elucidate the taxonomic scope of this group and (2) the discussion of the implications of the cladistic data gathered on Conulariidae systematic. A total of 17 characters were scored for the external and internal thecae morphology of 15 ingroup taxa (Archaeoconularia, Climacoconus, Conularia, Conularina, Ctenoconularia, Eoconularia, Metaconularia, Paraconularia, Pseudoconularia), including 6 genera (Teresconularia, Vendoconularia, Baccaconularia, Glyptoconularia, Notoconularia and Reticulaconularia), proposed after the publication of the TIP. Cubozoa, Stauromedusae, Coronatae and Semaeostomeae constituted the outgroup. Unweighted analysis of the data matrix yielded 124 trees. Successive weighting analysis resulted in 3 trees. The successive weighting trees indicated that the taxa Conularina, Baccaconularia and Glyptoconularia appear in different positions. The semi-strict tree is totally resolved, representing one of the 124 original trees found. In the semi-strict tree not all clades were supported by characters using ACCTRAN or DELTRAN optimizations. The clade ((Archaeoconularia, Metaconularia) (Conularina (Notoconularia (Climacoconus (Paraconularia, Reticulaconularia)))))) was collapsed, forming a politomy among ((Baccaconularia, Glyptoconularia) (Archaeoconularia, Metaconularia) (Conularina (Notoconularia (Climacoconus (Paraconularia, Reticulaconularia))))))), that was supported by the presence of external ornamentation in the midline. The data shows the internal group as monophyletic and is supported by the theca geometry in the oral section quadrate and the presence of mineralized periderm representing the conulariids autapomorphies. The clade (Notoconularia (Climacoconus (Paraconularia, Reticulaconularia))) is characterized by the interlaced arrangement of the corner sulcus ornamentation, the angulated corner sulcus morphology and the trochoidal transverse ribs. The alternate arrangement of the external ornamentation of the midline supports the clade (Climacoconus (Paraconularia, Reticulaconularia)). Any synapomorphy support the clade (Paraconularia, Reticulaconularia), being characterized by homoplasies. From the taxonomic point of view, the classical suprageneric groups (Conulariinae, Paraconulariinae and Ctenoconulariinae) recognized in the TIP were not identified. These groups are not phylogenetically valid, since they are supported by symplesiomophies and homoplasies only. Conulariid genera were classified as phylum Cnidaria, class Scyphozoa, order Conulariida and family Conulariidae. The examination of 1450 specimens indicated that Conularia milwaukeensis, C. quichua, C. albertensis, C. distincta, C. crenulata, C. expansa, C. tuberculata, C. acutilirata, Paraconularia ulrichana, P. africana, P. acuminata, P. pulcheria, P. derwentensis, Reticulaconularia baini and Baccaconularia cf. robinsoni yielded morphological features (septa, carina, articulation, arrangement of the corner sulcus ornamentation, external ornamentation in the midline) not previously described in the literature. Additionally, this study also encompassed the systematic review of ingroup members including the taxonomic reinterpretation of Vendoconularia (Ust? Pinega Formation, Proterozoic, Onega River, Russia), Malvinoconularia (Belén Formation, Devonian, Santa Cruz de La Sierra, Bolivia) and Baccaconularia (Saint Lawrence Formation, Upper Cambrian, United States), the redescription of C. milwalkeensis (Little Cedar Formation, Iowa and Milwaukee Formation, Wisconsin, Devonian, United States) and, finally, the description of Teresconularia, a new genus of Ordovician of Argentina. (AU)