Range extension of Thomasomys princeps (Thomas, 1895) (Rodentia, Sigmodontinae) and first record in Venezuela

Abstract

Thomasomys princeps (Thomas, 1895) is a large, sigmodontine rat and a member of the “aureus” group of the highly diverse genus Thomasomys. This species is only known from the Cordillera Oriental, Colombia; however, based on a recent examination of specimens of Thomasomys from Venezuela, I report the first record of T. princeps from Venezuela, in the Páramo del Tamá near the Colombian border. This record extends the distributional range of the species by 360 km northeast, representing the northernmost record of the species and of the “aureus” group.

A new species of Thomasomys Coues, 1884 (Rodentia: Sigmodontinae) from the montane forests of northern Peru with comments on the “aureus” group

“…nov. is also conspicuously distinct from congenerics by its large size (GLS: 45.39 mm), being second only to T. apeco, currently the largest living thomasomyine rodent (GLS: 51 mm; Leo L & Gardner 1993). Divergence of the new species respect to another species of the "aureus" group (5.47 % -10.17 %) fits the threshold of interspecific variation (Baker & Bradley 2006), similar to distances previously found among Thomasomys species using Cytb (e.g., Salazar-Bravo & Yates 2007, Brito et al 2019, 2021.…”

“…Our results based on morphological and molecular evidence support Thomasomys antoniobracki sp. nov. as a valid species, increasing to 47 the valid species of Thomasomys (Pacheco 2015, Brito et al 2019, 2021. Morphologically, T. antoniobracki sp.…”

“…Thomasomys aureus sensu lato needs to be assessed. T. aureus is the species of Thomasomys more widely distributed from central Colombia to Bolivia (Pacheco 2015(Pacheco , 2021. Although the type locality of the nominal form of T. aureus was not given by Tomes (1860), it was restricted to Pallatanga, Ecuador, by Pacheco (2015).…”

Systematic Revision of Thomasomys cinereus (Rodentia: Cricetidae: Sigmodontinae) from Northern Peru and Southern Ecuador, With Descriptions of Three New Species

“…Multivariate analyses were performed on measurements of adult specimens (age classes 3 and 4) to reduce intraspecific variation due to age (Rengifo and Pacheco, 2015; Pacheco, 2021). The variables RL and MFB (which were measured only on MUSM specimens) and GSL and CML (which were highly correlated with CBL) were not used in the multivariate analyses.…”

“…The discovery of new species is not unexpected because analyses of molecular sequence data have revealed the existence of cryptic species in several other sigmodontine genera, including Neacomys (Sánchez-Vendizú et al, 2018;Semedo et al, 2020), Nephelomys (Ruelas et al, 2021), and Rhipidomys (Brito et al, 2017). This taxonomic research and accumulating new records of Thomasomys (e.g., Moreno-Cárdenas and Novillo-Gonzalez, 2020;Pacheco, 2021) are improving our knowledge of the diversity and distribution of the genus, but we are still far from a comprehensive analysis of diversification and biogeography of these quintessentially montane-forest rodents . and to Mario López Mesones for sharing his deep knowledge of the Lambayeque region.…”