| Euopisthobranchia | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Heterobranchia clade Euthyneura |
| Taxonomic subdivisions | |
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See text |
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Euopisthobranchia is a taxonomic clade of snails and slugs in the clade Heterobranchia within the clade Euthyneura.[1]
Euopisthobranchia was established as a new taxon by Jörger et al. in October 2010.[1]
Euopisthobranchia is a monophyletic portion of the "Opisthobranchia" as that taxon was traditionally defined.[1]
Euopisthobranchia consist of the following taxa:[1]
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Previous studies discussed the gizzard (i.e. a muscular oesophageal crop lined with cuticula) with gizzard plates as homologous apomorphic structures supporting a clade composed of Cephalaspidea s.s., Pteropoda and Anaspidea.[1] A gizzard with gizzard plates probably originated in herbivorous taxa in which it worked like a grinding mill, thus might be secondarily reduced in carnivorous groups within Cephalaspidea s.s. and Gymnosomata.[1] Klussmann-Kolb and Dinapoli considered the gizzard in Umbraculoidea as non-homologous with the one in the previous groups, on account of the absence of gizzard plates or spines.[1] This contradicted Salvini-Plawen and Steiner, who had proposed the gizzard to be a synapomorphy of the larger clade of Paratectibranchia (Pteropoda, Cephalaspidea and Anaspidea) and Eleutherobranchia, secondarily lost in Nudipleura but still present in Umbraculoidea.[1] As coded in Wägele and Klussmann-Kolb, phylogenetic hypothesis by Jörger et al. (2010)[1] supports homology of the gizzard in Umbraculoidea with the gizzard with gizzard plates and spines in the other euopisthobranchian taxa.[1] Thus, the structure is proposed as a synapomorphy of Euopisthobranchia.[1]
A cladogram showing phylogenic relations of the Heterobranchia as proposed by Jörger et al. (2010):[1]
| Heterobranchia |
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This article incorporates CC-BY-2.0 text from the reference [1].