''Rhaebo'' is a genus of true toads, family Bufonidae, from Central and South America. They are distributed from Honduras to northern South America including the Amazonian lowlands. Common name Cope toads has been suggested for them.
Taxonomy
The genus was removed from the synonymy of '' Bufo'' in 2006; an alternative view has been to treat it as a
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
of ''Bufo''. At present, it is widely recognized as a genus.
''Andinophryne'', consisting of three species, was recognized as a separate genus until 2015 when it was found out that its recognition rendered ''Rhaebo''
paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
. An alternative to synonymizing it with ''Rhaebo'' would have been to erect a new genus for '' Rhaebo nasicus'', but this would have caused difficulty in assigning species without molecular data to correct genus.
Description
''Rhaebo'' are characterized as lacking cephalic crests, having omosternum, distinctively wide sphenethmoid, prominent and notched
exoccipital condyles
The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the c ...
, and yellowish-orange skin secretions. It is not clear which of these characters are ancestral and which are derived (i.e.,
synapomorphies
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...