Transandinomys bolivaris
[17] In 1939, Oliver Pearson added a third subspecies, O. b. orinus, from eastern Panama,[18] and in 1966 the species was first recorded from Colombia.[19] Ronald Pine reviewed Oryzomys bombycinus in 1971, when 59 specimens of it were known, and first recorded the species from Nicaragua and Ecuador.They considered O. bolivaris as probably the same as O. nitidus and listed castaneus as a synonym of O. capito (equivalent to modern Hylaeamys megacephalus and closely related species plus Transandinomys talamancae).[23] Guy Musser and Marina Williams reviewed O. talamancae in 1985 and included O. castaneus as one of its synonyms, though without having examined the holotype.[27] In 2006, Marcelo Weksler published a phylogenetic analysis of Oryzomyini ("rice rats"), the tribe to which Oryzomys is allocated, using morphological and DNA sequence data.The two species are morphologically similar, but they could identify only one synapomorphy (shared-derived trait) for them: very long superciliary vibrissae (whiskers above the eyes).[10] In both species, the mystacial vibrissae (above the mouth) are also long and extend beyond the ears when laid back, but they are again much longer in T. bolivaris.[52] Ungual tufts of long, white or gray hairs are present around the claws,[53] which are short and lack pigment.[52] Although the subspecies previously recognized in "Oryzomys bombycinus" have been separated by small differences in skull features, Pine rejected these on the basis of his much larger samples.The margins of the interorbital region contain prominent beads, which extend to the braincase as temporal ridges;[45] these are usually less well-developed in T. talamancae.[58] Unlike in T. talamancae and H. alfaroi, the parietal bone is usually limited to the roof of the braincase and does not extend to the sides.[61] The capsular process, a projection at the back of the jaw which houses the root of the lower incisor, is poorly developed.[61] As in this species, but unlike in many other rice rats, including H. alfaroi, the mesoflexus on the second upper molar, which separates the paracone (one of the main cusps) from the mesoloph (an accessory crest), is not divided in two by an enamel bridge.[62] The hypoflexid on the second lower molar, the main valley between the cusps, is very long, extending more than halfway across the tooth; in this trait, it is similar to T. talamancae but unlike H. alfaroi.[39] Its known distribution extends from northeastern Honduras, on the Caribbean seaboard, through eastern Nicaragua, Costa Rica, and Panama, into coastal western Colombia and northwestern and west-central Ecuador.[39] The actual range of this species may be expected to extend further north and west, perhaps into Veracruz, southern Mexico, and western Venezuela, where it has not yet been recorded.
Conservation statusLeast ConcernIUCN 3.1Scientific classificationEukaryotaAnimaliaChordataMammaliaRodentiaCricetidaeSigmodontinaeTransandinomysBinomial nameJ.A. AllenSynonymsGoldmanrodentfamilyTransandinomys talamancaerice ratvibrissaeinterorbital regionJoel Asaph AllenOryzomysOryzomys perenensisBolívar ProvinceEsmeraldas ProvincePichincha ProvincePhilip HershkovitzOryzomys laticepsHylaeamys laticepsEdward Alphonso GoldmanOryzomys talamancaesubspeciesOryzomys nitidusHylaeamys megacephalusGuy MusserholotypeMammal Species of the WorldphylogeneticOryzomyinimorphologicalDNA sequencetype speciessynapomorphywhiskerscommon nameHandleyomys alfaroiungual tuftssquamaemammaethoraciclumbarchromosomeskaryotypebraincasezygomatic plateszygomatic archesparietal boneincisive foraminapalatemolarsposterolateral palatal pitssphenopalatine vacuitiesauditory bullaemastoid bonearteriesforaminaMandiblecondyloid processcapsular processincisorenamelopisthodontbrachydontmesoflexusparaconemesolophhypoflexidVeracruzLake Maracaibosemiplumbeous hawkSigmodontomys alfariS. aphrastusProechimys semispinosusHoplomys gymnurusHaemolaelaps glasgowichiggersIUCN Red Listprotected areashabitat destructionIUCN Red List of Threatened SpeciesOxford University PressOryzomyini (rice rats)AegialomysA. galapagoensisA. xanthaeolusAgathaeromysA. donovaniA. praeuniversitatisAmphinectomysA. savamisCarletonomysC. cailoiCerradomysC. goytacaC. langguthiC. maracajuensisC. marinhusC. scottiC. subflavusC. vivoiDrymoreomysD. albimaculatusEremoryzomysE. poliusEuryoryzomysE. emmonsaeE. lamiaE. legatusE. macconnelliE. nitidusE. russatusHandleyomysH. alfaroiH. chapmani