New rodents (Cricetidae) from the Neogene of Curaçao and Bonaire, Dutch Antilles

Abstract

Cordimus, a new genus of cricetid rodent, is described from Neogene deposits on the islands of Curac ßao and Bonaire, Dutch Antilles. The genus is characterized by strongly cuspidate molars, the presence of mesolophs in most upper molars and the absence of mesolophids in lower molars. Similarities with the early cricetid Copemys from the Miocene of North America coupled with apparent derived characters shared with the subfamily Sigmodontinae suggest that Cordimus may be close to the root of the sigmodontine lineage, a possibility that remains to be tested through explicit phylogenetic analysis. Three species are recognized on the basis of size and details of molar morphology. Cordimus hooijeri sp. nov. is described from Bonaire on the basis of Holocene owl pellet material that consists of dentaries and postcranial material only. This species is presumed to be extinct, but focused surveys are needed to confirm this hypothesis. Cordimus debuisonjei sp. nov. and Cordimus raton sp. nov. are described from deposits on Tafelberg Santa Barbara in Curac ßao. Although the age of these deposits is not known, they are most likely of late Pliocene or early Pleistocene age. Both are represented by numerous isolated molars and some osteological material.

Pliocene sigmodontine rodents (Mammalia: Cricetidae) in northernmost South America: test of biogeographic hypotheses and revised evolutionary scenarios

“…Nevertheless, even when our understanding of Andean and Amazonian Neogene palaeogeography dramatically increased during the last four decades ([127] and references therein), there have been few additions to our knowledge of the sigmodontine fossil record. One promising finding is the sigmodontine † Cordimus , a genus with three species described from Quaternary deposits in the Caribbean islands of Curaçao & Bonaire [131]. Although one of the species, † Cordimus hooijeri , restricted to the Late Holocene in Bonaire seems unrelated to the other two (resembling more probably Oligoryzomys ), at least the type species of the genus deserves closer attention.…”

“…Although one of the species, † Cordimus hooijeri , restricted to the Late Holocene in Bonaire seems unrelated to the other two (resembling more probably Oligoryzomys ), at least the type species of the genus deserves closer attention. It is † Cordimus debuisonjei , collected in Curaçao, from sediments supposedly bracketed between 2.3 and 1.3 Ma [131]. This form, characterized by brachydont complex molars resembling oryzomyines in occlusal morphology, shows several unusual traits among sigmodontines, including the single condition (i.e.…”

“…being constituted by only one conulid [38]) on the procingulum of the m1 associated with the absence of mesolophid on this same molar (fig. 2 d in [131]). The phylogenetic affinities of † Cordimus are unknown as well as its tribal affiliation, although it was compared to † Copemys and several North American fossil Miocene muroids [131].…”

“…2 d in [131]). The phylogenetic affinities of † Cordimus are unknown as well as its tribal affiliation, although it was compared to † Copemys and several North American fossil Miocene muroids [131]. Maybe † Cordimus could be an important piece of information to support a Caribbean dispersion to South America.…”

The taxonomic status of Copemyodon ecuadorensis (Rodentia, Cricetidae), a supposedly extinct muroid from the Ecuadorean Quaternary

“…Musser and Carleton 2005) and in a few reviews about the evolutionary history of the group (e.g. Pardiñas et al 2002, Zijlstra et al 2014. As an example of the destiny of a plethora of fossil forms in a universe, currently dominated by molecular systematics, characteristic of the recent record of sigmodontine rodents, two decades later Copemyodon integrates a large number of enigmatic taxa.…”