Amerigo Vespucci and the rat of Fernando de Noronha : a new genus and species of Rodentia (Muridae, Sigmodontinae) from a volcanic island off Brazil's continental shelf. American Museum novitates ; no. 3256

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New York, NY : American Museum of Natural History
"Noronhomys vespuccii, a new genus and species (Muridae: Sigmodontinae), is described from Ilha Fernando de Noronha, a small volcanic island located 345 km northeast of Cabo de São Roque, Brazil. The abundant cranial and postcranial material of the fossil rodent was recovered from old beach dunes that are late Quaternary in age (probably late Holocene). Noronhomys vespuccii retains incomplete mesolophs on its moderately hypsodont molars and is compared with other tetralophodont oryzomyines (sensu Voss and Carleton, 1993), especially Lundomys molitor and species of Holochilus. Morphometric analyses conducted separately on craniodental, mandibular, and femoral measurements reveal the sample of Noronhomys to be equally differentiated from those of Lundomys and Holochilus. Based on the criterion of parsimony, phylogenetic analyses of 35 craniodental characters strongly support the recent common ancestry of the new form and Holochilus. The clade (Pseudoryzomys (Lundomys (Holochilus-Noronhomys))) appears to represent a lineage of semiaquatic rodents that differentiated from an oryzomyine ancestry in savanna landscapes of southern South America. Morphometric results and anatomical details of the pelvic limb, however, suggest that Noronhomys was not a semiaquatic form. It is hypothesized that such aquatic skeletomuscular adaptations were lost (reversed) when the progenitor of Noronhomys became stranded on a small oceanic island where palustrine habitats were scarce or absent. The specific patronym of the extinct rodent refers to Amerigo Vespucci's disputed landfall on Fernando de Noronha in 1503 and his possible sighting of 'very large rats' on that island. If the species Noronhomys vespuccii were alive in 1503, it became extinct shortly thereafter due to the usual anthropogenic causes that have extirpated so many vertebrate species on islands"--P. 2.
59 p. : ill. ; 26 cm.
Includes bibliographical references (p. 56-59).