Sphiggurus vestitus pruinosus mammalia rodentia erethizontidae the karyotype and its phylogenetic implications descriptive notes

Concepcion, J. L.; Molinari, J.

doi:10.1080/01650529109360858

Sphiggurus vestitus pruinosus, a porcupine from western Venezuela, has a karyotype with a diploid number (2n) of 42, and a fundamental number (FN) of 76. The autosomes consist of 34 metacentric and submetacentric, 2 subacrocentric, and 4 acrocentric chromosomes. The X-chromosome is submetacentric, and the Y-chromosome is acrocentric. This karyotype is identical is gross morphology to that of the North American porcupine, Erethizon dorsatum, but differs markedly from the 2n = 74 and FN = 82 karyotype of the Panamanian porcupine, Coendou rothschildi. These findings are unexpected considering that Sphiggurus and Coendou resemble morphologically more to each other than either of them of Erethizon, and are most parsimoniously explained by retaining the hypothesis of a closer cladistic relationship between Sphiggurus and Coendou and by proposing the 2n-74 and FN = 82 karyotype to be autapomorphic. The karyological information is complemented with observations on cranial and external characters. The results support recognition of Sphiggurus and Coendou as separate genera.