Euopisthobranchia
| Euopisthobranchia | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Heterobranchia clade Euthyneura |
| Taxonomic subdivisions | |
|
See text | |
Euopisthobranchia is a taxonomic clade of snails and slugs in the clade Heterobranchia within the clade Euthyneura. This clade 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 but is not a replacement name for that group as several marine opisthobranch orders including Sacoglossa and Acochlidiacea are not included.[1]
Euopisthobranchia consist of the following taxa:[1]
Gizzard
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]
Cladogram
A cladogram showing phylogenic relations of the Heterobranchia as proposed by Jörger et al. (2010):[1]
| Heterobranchia |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |
See also
- Changes in the taxonomy of gastropods since 2005#Heterobranchia
- Heterobranchia#2010 taxonomy
- Acochlidiacea#2010 taxonomy
References
This article incorporates CC-BY-2.0 text from the reference.[1]
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Jörger K. M., Stöger I., Kano Y., Fukuda H., Knebelsberger T. & Schrödl M. (2010). "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia". BMC Evolutionary Biology 10: 323. doi:10.1186/1471-2148-10-323.