Oryzomys xanthaeolus ica Osgood, 1944

Prado, Joyce Rodrigues Do & Percequillo, Alexandre Reis, 2016, Systematic studies of the genus Aegialomys Weksler, Percequillo and Voss, 2006 (Rodentia: Cricetidae: Sigmodontinae): Annotated catalogue of the types of the species-group taxa, Zootaxa 4144 (4), pp. 477-498 : 492-494

publication ID

https://doi.org/ 10.11646/zootaxa.4144.4.2

publication LSID

lsid:zoobank.org:pub:8CC5C9D3-6575-433D-B6B5-CD2B1CE6B80A

DOI

https://doi.org/10.5281/zenodo.5624973

persistent identifier

https://treatment.plazi.org/id/03B487F6-FF80-FFDA-FF56-FA4BFF68FA69

treatment provided by

Plazi

scientific name

Oryzomys xanthaeolus ica Osgood, 1944
status

 

Oryzomys xanthaeolus ica Osgood, 1944

Holotype. FMNH 53157, a female specimen, deposited at The Field Museum, collected by C. C. Sanborn, in 17.I.1942 ( Fig. 7 View FIGURE 7 ).

Type condition. Specimen preserved in skin and skull; both of them are in excellent condition, without any broken part.

Type material. The type material consists of two specimens: the holotype, described above, and the paratype ( FMHN 53158), an adult female.

Type locality. Hacienda San Jacinto , near Ica, Province of Ica, southwestern Peru . The geographical coordinates of this locality are 14°09’S, 75°45’W. The type locality is represented in figure 3.

Original description. Osgood described Oryzomys xanthaeolus ica in the Zoological Series of the Field Museum of Natural History, vol. 29, n.13, 1944:192–193, providing the following simplified characterization:

“Similar in color and general characters to O. x. xanthaeolus but somewhat larger and having a skull with definitely larger audital bullae.”

Original dimensions. Total length: 325 mm; tail: 161 mm; hindfoot: 33 mm. Skull-greatest length: 44.8 mm; zygomatic breadth: 19.3 mm; breadth of braincase: 13.5 mm; interorbital space: 6.1 mm; nasals: 14.3 x 4.5 mm; diastema, 8.5 mm; palatine foramina: 7.3 mm; upper toothrow, 5.5 mm. Other craniodental measurements are in table 2.

Morphological description. Dorsal pelage soft, lax, dense and long; yellowish to ochraceous wool and cover hairs, intensely grizzled with brown guard hairs, resulting in dorsal color ochraceous cream grizzled with brown; venter grayish cream; tail slightly shorter than head and body length, densely covered with hairs, weakly bicolor, with large scales with approximately 18 scales/cm and without terminal tuft; pes covered by very long and white hairs; ungual tufts dense and long, white; interdigital and plantar pads developed, thenar and hypothenar fleshy; pinnae with few external hairs and with a creamy and yellowish coloration and inner hairs light yellow.

Skull very large and robust, with moderately long and broad rostrum (approximately 36% of skull length [LN/ ONL ratio]); zygomatic plate moderately projected anteriorly, not reaching beyond nasolacrimal capsule; rostral fossa very deep; moderately projected plate and very deep fossa, configuring a moderately deep and very wide zygomatic notch; interorbital region strongly diverging posteriorly, with strongly beaded supraorbital margins; zygomatic arches strongly divergent posteriorly, wider near the squamosal root; braincase elongated, with temporal margins squared, without crests; interparietal short and wide; fronto-squamosal suture contiguous with frontoparietal suture; alisphenoid strut absent; anastomotic channel present, configuring pattern 3 of carotid circulation ( Voss 1988); parietals expanding over surface side of skull; postglenoid foramen apparently small; incisive foramen long, wider medially, with anterior and posterior margins slightly acute, posterior margin reaching anterocone of M1; posterior margin of zygomatic plate situated anterior to the alveolus of M1; palate intermediate, with deep posterolateral palatal pits recessed in deep and large palatine depressions; palate apparently without palatal excrescencies; mesopterygoid fossa perforated by very large sphenopalatine vacuities on the presphenoid and basisphenoid; auditory bulla large, with very short and narrow stapedial process.

Upper incisors opisthodont; upper molars with labial and lingual cusps arranged in opposite pairs; M1 with anteroloph short and narrow, almost entirely fused to anterocone; anterocone apparently with shallow anteromedian flexus; paracone connected medially to protocone; median mure more labially positioned, defining a long and deep hypoflexus; paracone connected labially to mesoloph, forming a small, round and labially positioned mesofosset; mesoloph moderately long, connected with median mure medially; mesoloph separated from metacone by metaflexus; M2 similar to M1, but with median mure more medially positioned; paracone connected medially to protocone; mesoloph long, connected labially to paracone, forming a small, rounded and slightly oblique mesofosset; M3 small, triangular.

Observations. According to Osgood (1944) specimens of O. xanthaeolus ica are in overall larger and have a large auditory bulla when compared with the O. xanthaeolus from nearby localities. After its original description, O. xanthaeolus ica remained as a subspecies of O. xanthaeolus until the early 1990’s, when Musser and Carleton (1993) synonymized it with O. xanthaeolus in the catalogue “Mammal Species of the World” (Wilson & Reeder 1993).

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Rodentia

Family

Muridae

Genus

Oryzomys

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