Abstract
A new Oryzomys species was described on the basis of 31 specimens obtained in the Cerrado of central Brazil. This new large-bodied Oryzomyini possesses a tail that is longer than head and body, a soft and long pelage, and a dresden brown dorsum lined with black. It can be diagnosed by virtue of the skull which shows well developed and anteriorly convergent supraorbital ridges, a long and narrow incisive foramen, a long palate, very reduced or absent sphenofrontal vacuities. It further shows a diploid number of 56 chromosomes coupled with a relatively lower fundamental number of 54. This new Oryzomys species is endemic to the Brazilian Cerrado, belonging to the O. subflavus species group. A comparison using morphological, karyological, and cytochrome b DNA sequence data was carried out to elucidate its relationship with other species of Oryzomys, mainly from the subflavus species group. Molecular analysis suggested the monophyly of the subflavus variants, placed the clade Oryzomys sp. nov - Oryzomys sp. 2 as the most basal offshoot within this group, whereas O. subflavus was the most derived species.
Zusammenfassung
Eine neue Oryzomys-Art wurde an Hand von 31 Individuen aus dem Cerrado in Zentral-Brasilien beschrieben. Diese große Oryzomyini-Art hat einen Schwanz, dessen Länge die Kopf-Rumpflänge übertrifft, ein Langes, weiches Fell, und einen ockerbraunen (Dresden brown) Rücken. Diagnostische Schädelmerkmale sind gut entwickelte und nach vorn konvergierende supraorbitale Kämme, lange und schmale Incisiv-Foramia, langes Palatinum und sehr reduzierte oder fehlende sphenofrontale Lücken. Diagnostische karyologische Merkmale sind 2 n = 56, zusammen mit einer relativ niedrigen FNA = 54. Diese neue Oryzomys-Art ist endemisch im brasilianischen Cerrado, und gehört zu der O. subflavus-Artengruppe. Morphologie, Karyologie und DNA Cytochrome b-Sequenzierung wurden benutzt, um die Beziehung zu anderen Arten von Oryzomys, besonders von der subflavus-Artengruppe, zu erhellen. Die Molekular-Analyse legt die Monophylie der subflavus-Gruppe nahe, in der Oryzomys sp. nov. - Oryzomys sp. 2. einen basalen Abzweig bildet, während O. subflavus die am meisten abgeleitete Art ist.
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Bonvicino, C.R. A new species of Oryzomys (Rodentia, Sigmodontinae) of the subflavus group from the Cerrado of Central Brazil. Mamm Biol 68, 78–90 (2003). https://doi.org/10.1078/1616-5047-00066
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DOI: https://doi.org/10.1078/1616-5047-00066