Phylogenetic relationships of the pygmy rice rats of the genus Oligoryzomys Bangs, 1900 (Rodentia: Sigmodontinae)

Abstract

Sequences from two mitochondrial genes (cytochrome b and NADH1) were used to produce a molecular phylogeny for 12 named and two undescribed species of the genus Oligoryzomys. All analyses placed Oligoryzomys microtis as the most basal taxon, a finding consistent with previous studies that suggested the west-central Amazon as a centre of origin for the tribe Oryzomyini to which Oligoryzomys belongs. Biogeographically, this suggests that Oligoryzomys had a South American origin, and later advanced northwards, entering Central America and Mexico more recently. Different analyses have provided consistent support for several additional clades that did not necessarily agree with the species groups hypothesized by previous studies. A molecular clock derived for these data suggests an origin for the genus of 6.67 Mya, with most speciation within the genus occurring between 3.7 and 1.5 Mya.

The Taxonomic Status ofOligoryzomys mattogrossae(Allen 1916) (Rodentia: Cricetidae: Sigmodontinae), Reservoir of Anajatuba Hantavirus

“…8). Some clades recovered in the present study, both in the mt-Cytb only and in combined analyses, are generally coincident with recent studies of Oligoryzomys (Palma et al, , 2010aFrancés and D'Elía, 2006;Rivera et al, 2007;Rogers et al, 2009;Miranda et al, 2009;Richter et al, 2010;González-Ittig et al, 2010 …”

“…Recent phylogenetic studies of this genus (Rivera et al, 2007;Rogers et al, 2009;Miranda et al, 2009;Palma et al, 2010a;González-Ittig et al, 2010Hanson et al, 2011;Agrellos et al, 2012;Teta et al, 2013) have shown that Oligoryzomys systematics is still controversial, probably due to the high phenotypic similarity between species, which makes diagnosis and species identification difficult (see Musser, 1989, 1995;Weksler andBonvicino, 2005, 2015, for historical accounts of the generic taxonomy). In addition, molecular studies not employing morphological examination of specimens hinders further advance of the systematics of the genus, as specific names have been attached to several exemplars without a proper morphological assessment or that are based solely on geographic proximity of species ranges or type localities.…”

Ecology of Rodent-Associated Hantaviruses in the Southern Cone of South America: Argentina, Chile, Paraguay, and Uruguay

“…Although in general, each hantavirus is associated with a single primary host species, several apparent exceptions to this pattern in the Southern Cone may relate to our imperfect knowledge of the taxonomy of the host species. Recent work on the phylogenetics of Oligoryzomys Gonzalez-Ittig et al, 2010;Palma et al, 2010) has contributed to our understanding of the complexity of the relationships between species of Oligoryzomys and several hantaviruses. We now know, for example, that the host for Oran virus is Oligoryzomys chacoensis, not Oligoryzomys longicaudatus (host for ANDV), as originally described .…”

“…Nevertheless, the complex and still relatively poorly understood systematics of many sigmodontine rodents in South America, combined with the scant sampling records for some taxa, complicate the documentation of accurate distributional data. Although several species once believed to be distributed across large geographic areas (e.g., O. longicaudatus and O. flavescens) are being recognized as complexes of species or subspecies Palma et al, 2010;Gonzalez-Ittig et al, 2010), other widespread species (e.g., C. laucha) are still in need of careful taxonomic study.…”

A new species of fish-eating rat, genus Neusticomys (Sigmodontinae), from Ecuador

“…5 to 10 % [Feijoo et al 2010;D'Elía et al in press]; species of the Akodon boliviensis species group: 2.8-7.7 % [Jayat et al 2010]; Eligmodontia: 4.6-11.4 % [Mares et al 2008]; Juliomys: ca. 12 % ; Melanomys: 4.5-7.6 % [Hanson and Bradley 2008]; Nectomys: 7.36 % [Hanson and Bradley 2008]; Oligoryzomys: 4.45-15 % [Hanson et al 2011;Palma et al 2010;Richter et al 2010;Rogers et al 2009]; Oryzomys: 4.5-12.1 % ; Oxymycterus: 2.5-9.6 % [Jayat et al 2008 [Henson and Bradley 2009]). Although the species used for comparison are not the closest possible relatives to Neusticomys, all belong to other sigmodontine tribes and provide a diverse array of reference points.…”