Euryzygomatinae is a subfamily of rodents, proposed in 2017, and containing three extant genera of spiny

Echimyidae Echimyidae is the family of neotropical spiny rats and their fossil relatives. This is the most species-rich family of hystricognath rodents. It is probably also the most ecologically diverse, with members ranging from fully arboreal to terr ...

: '' Clyomys'', '' Euryzygomatomys'', and '' Trinomys''. Members of this echimyid subfamily all share an origin in the eastern part of Brazil, close to the Atlantic Forest.

Morpho-anatomy

The teeth of Euryzygomatomyines are characterized by several features: * elongate lower and upper incisor roots ; * five lophids on the lower deciduous premolars 4 ; * either four lophids in ''Trinomys'', or three lophids in ''Clyomys'' and ''Euryzygomatomys'', on the lower molars 1 ; * well-connected lophs on the cheek teeth ; * three molar roots anchoring the upper molars. Their

zygomatic arch In anatomy, the zygomatic arch (colloquially known as the cheek bone), is a part of the skull formed by the zygomatic process of temporal bone, zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the ...

is reduced with a slightly concave dorsal margin, and the

jugal bone The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic bone, zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by spe ...

is ventrally expanded with much reduced, scarcely salient inferior process.

Molecular signatures

At the protein level, one amino acid replacement from

leucine Leucine (symbol Leu or L) is an essential amino acid that is used in the biosynthesis of proteins. Leucine is an α-amino acid, meaning it contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-Car ...

proline Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the p ...

yields a shared derived character state that is diagnostic for defining the Euryzygomatomyinae: the amino-acid proline at position homologous to site 294 of the human GHR.

Phylogeny

Within Euryzygomatomyinae, '' Clyomys'' is the sister group to '' Euryzygomatomys''. In turn, these two

fossorial A fossorial animal () is one that is adapted to digging and which lives primarily (but not solely) underground. Examples of fossorial vertebrates are Mole (animal), moles, badgers, naked mole-rats, meerkats, armadillos, wombats, and mole salamand ...

genera are the sister group to the terrestrial '' Trinomys''. In the phylogeny of the family Echimyidae, Euryzygomatomyinae is the sister group to a large assemblage comprising '' Carterodon'' and the family Capromyidae. These phylogenetic relationships, based on the comparison of complete

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

genomes and

nuclear DNA Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. ...

exons, disagree with analyses of craniodental characters which cluster together the fossorial genera ''Clyomys'', ''Euryzygomatomys'' and ''Carterodon''.

References

{{Taxonbar, from=Q48837034 Echimyidae Mammal subfamilies Rodents of Brazil