Hebetancylus [SEP] parent taxon
Hebetancylus
Hebetancylus is a genus of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod molluscs in the family Planorbidae, the ram's horn snails and their allies.
Anatomy.
These animals have a pallial lung, as do all pulmonate snails, but they also have a false gill or "pseudobranch" which can serve perfectly well as a gill when they are unable to reach the surface for air.
Species.
Species within the genus "Hebetancylus" include:
- "Hebetancylus excentricus"
Taxon in disguise
In bacteriology, a taxon in disguise is a species, genus or higher unit of biological classification whose evolutionary history reveals has evolved from another unit of similar or lower rank, making the parent unit paraphyletic. This happens when rapid evolution makes a new species appear radically different from the ancestral group, so that it is not (initially) recognised as belonging to the parent phylogenetic group, leaving the latter an evolutionary grade.
While the term is from bacteriology, parallel examples are found throughout the tree of