Paratilapia
Encyclopedia
Paratilapia is a genus
of cichlid
s with only two known species. They occur on Madagascar
.
Phylogenetic analsysis of DNA sequence
and morphological
data have hitherto been unable to resolve the relationships of the genus to satisfaction. For example sequence data from mtDNA 16S rRNA and COI
disagrees regarding its placement (Sparks 2004), and the standard hypothesis among cichlids - that this is due to hybridization effects - can obviously not apply here as both genes are mitochondrial and affected by hybrid introgression in the same way.
In any case, Paratilapia tends to occupy a position between African subfamilies such as the Ptychochrominae
and the Indo-Malagasy clade
comprising Etroplinae
and Ptychochrominae
in most analyses, and this may well be correct. If so, its ancestors must have separated from those of all other living cichlids in the Mesozoic
. They most probably were already a distinct lineage by the Turonian
(c.90 mya), as the Indo-Malagasy clade must have originated before the split of Madagascar from the Indian Platewhich commenced then and was finished by the end of the Cretaceous
.(Sparks 2004)
Consequently, they would have to be classified as a subfamily of their own, Paratilapiinae.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of cichlid
Cichlid
Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...
s with only two known species. They occur on Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
.
Phylogenetic analsysis of DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
and morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
data have hitherto been unable to resolve the relationships of the genus to satisfaction. For example sequence data from mtDNA 16S rRNA and COI
Cytochrome c oxidase
The enzyme cytochrome c oxidase or Complex IV is a large transmembrane protein complex found in bacteria and the mitochondrion.It is the last enzyme in the respiratory electron transport chain of mitochondria located in the mitochondrial membrane...
disagrees regarding its placement (Sparks 2004), and the standard hypothesis among cichlids - that this is due to hybridization effects - can obviously not apply here as both genes are mitochondrial and affected by hybrid introgression in the same way.
In any case, Paratilapia tends to occupy a position between African subfamilies such as the Ptychochrominae
Ptychochrominae
Ptychochrominae is a subfamily in the cichlid family of fishes. They are restricted to lakes and rivers in Madagascar, and the majority are threatened...
and the Indo-Malagasy clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
comprising Etroplinae
Etroplinae
Etroplinae is a subfamily in the cichlid family of fishes. The subfamily includes two genera: Etroplus, which are the only cichlids native to India and Sri Lanka, and Paretroplus from Madagascar .-References: : Molecular phylogeny and biogeography of the Malagasy and South Asian...
and Ptychochrominae
Ptychochrominae
Ptychochrominae is a subfamily in the cichlid family of fishes. They are restricted to lakes and rivers in Madagascar, and the majority are threatened...
in most analyses, and this may well be correct. If so, its ancestors must have separated from those of all other living cichlids in the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
. They most probably were already a distinct lineage by the Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
(c.90 mya), as the Indo-Malagasy clade must have originated before the split of Madagascar from the Indian Platewhich commenced then and was finished by the end of the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
.(Sparks 2004)
Consequently, they would have to be classified as a subfamily of their own, Paratilapiinae.