Juliomys anoblepas is a rodent in the genus Juliomys of the subfamily Sigmodontinae known from a single broken skull. The specimen was collected by Peter Wilhelm Lund in the caves of Lagoa Santa, Minas Gerais, Brazil, in the first half of the 19th century and described by Herluf Winge in 1888 as Calomys anoblepas. The species remained unstudied and its affinities unclear until 2011, when it was recognized as a member of the genus Juliomys, which includes three other species from southern Brazil and nearby Argentina and Paraguay. J. anoblepas is probably a separate extinct species of the genus, which is no longer found at Lagoa Santa. Juliomys anoblepas is similar to the other members of its genus in the configuration of its zygomatic plate (a bony plate on the side of the skull). It hardly extends forward in front of the connection between the plate and the main body of the skull, and that connection is relatively low on the skull. Furthermore, the incisive foramina, openings in the front part of the palate, extend to a point between the first molars, and the palate is short, with its back margin between the third molars. The living species of Juliomys differ from J. anoblepas in various characters, including shorter incisive foramina in two species and the shape of the zygomatic arch (cheekbone) in J. anoblepas. The upper molar row is 4.13 mm long, which makes J. anoblepas the largest known species of Juliomys.
Taxonomy Between 1835 and 1849, Danish zoologist Peter Wilhelm Lund collected abundant remains of mammals around the village of Lagoa Santa in Brazil. After his death, his fellow Dane Herluf Winge described Lund's collections in detail, among many others publishing a monograph about the rodents of the collection in 1888. Winge described numerous new species, many of which received little attention from systematists afterward, and among these is the species he named Calomys anoblepas. The specific name, anoblepas, derives from the Greek ἄνω (ano) "upwards" and βλέπω (blepo) "to look" and thus means "looking upward". Although Winge did not explain the name, it most likely refers to the zygomatic plate (a bone plate at the side of the skull), which is bended outward. Winge understood the genus Calomys in a sense very different from that used today, including in it the species Calomys longicaudatus (currently Oligoryzomys nigripes), Calomys coronatus (currently Euryoryzomys russatus), Calomys rex (currently Sooretamys angouya), Calomys laticeps (currently Cerradomys subflavus), Calomys saltator (currently Hylaeamys laticeps), and Calomys plebejus (currently Delomys, species uncertain). He wrote that C. anoblepas was the most divergent of the species of Calomys, but that it was similar to C. longicaudatus. Winge's concept of the genus Calomys essentially included unspecialized species with pentalophodont molars, which are characterized by the presence of a crest known as the mesoloph on the upper and mesolophid on the lower molars, and excluded species now placed in Calomys, which he classified in Hesperomys instead. Since 1898, authors have placed Winge's Calomys species in Oryzomys, conforming to the more conventional taxonomic arrangement; after that, the species was referred to as Oryzomys anoblepas. Over many decades, the identity of most of Winge's species remained uncertain, and in many cases it was not until the 1990s that the original material was restudied to provide a definitive identification of the material. In a 2002 review of the fossil sigmodontine rodents of South America, Argentinean zoologist Ulyses Pardiñas and his coworkers wrote that O. anoblepas was "possibly an Oecomys", but this claim was based only on a cursory investigation. In 2011, Pardiñas and Pablo Teta published another paper on "Calomys anoblepas" after re-examining the only known specimen in Copenhagen, and concluded that the animal was instead related to the living genus Juliomys, which currently includes three living species from southern Brazil and nearby Paraguay and Argentina. They recognized some features by which J. anoblepas differs from the living species, and consequently kept it as a distinct, extinct species. Juliomys is a genus of unclear relations within the subfamily Sigmodontinae, which is widespread and very diverse in South America and southern North America.
… excerpt ends here. Continue reading the full article.
