An Annotated Checklist of Recent Opossums (Mammalia: Didelphidae)

Abstract

Living opossums (Didelphidae) comprise 125 species in 18 genera and 4 subfamilies. This synopsis lists all the didelphid taxa (subfamilies, tribes, genera, subgenera, and species) currently recognised as valid, summarizes information about typification, synonyms, and geographic distributions, remarks noteworthy recent changes in usage, and comments on still outstanding problems. A concluding discussion rejects the notion that the almost twofold increase in opossum species from 1993 to the present is "taxonomic inflation" and considers the impact of new kinds of data and new methods of data analysis on species delimitation.

New species of the Spiny Mouse genus Neacomys (Cricetidae, Sigmodontinae) from northwestern Ecuador

“…A gnatic process is not developed; the zygomatic plate is wide and excavated (> M1 length) and slightly inclined backward; the zygomatic arch slender and without a jugal; a squamosal-alisphenoid groove is visible through the translucent braincase (Fig. 8B, E ), with a perforation where it crosses the depression for the masticatory nerve; the stapedial foramen is present and small, the carotid canal is small, and the petrotympanic fissure is expressed (Figs 8C ); the cephalic arterial supply is primitive (pattern 1 of Voss 1988 ); the alisphenoid strut is absent; an anterior opening of the alisphenoid canal is absent; the postglenoid foramen is large; the subsquamosal fenestra is small and the hamular process of the squamosal is long; a small tegmen tympani is present (Fig. 8A ); there is no contact between the anterodorsal edge of the ectotympanic and the mastoid tubercle, which leads to an opened ectotympanic ring (Fig.…”

New departmental and noteworthy records of mammals (Mammalia, Theria) from Nicaragua

“…This work is dedicated to the memory of Arnulfo Medina-Fitoria (1974-2022, a Nicaraguan mammalogist. We thank the Ministerio de Ambiente y Recursos Naturales, Programa para la Conservación de Murciélagos de Nicaragua (PCMN), and Paso Pacifico for logistical support and research permits.…”

Updated list of the mammals of Costa Rica, with notes on recent taxonomic changes

“…As "M. alstoni", the species was hypothesized to be distributed from Belize to Colombia, with a break in Panama. However, , in a revision of the Alstoni Group of Marmosa, showed using genetics and morphology that M. alstoni and M. nicaraguae were distinct at the species level, and restricted M. nicaraguae to the Caribbean coastal lowlands of Nicaragua and Costa Rica (potentially extending into the foothills; see Voss 2022), and M. alstoni to the central highlands of Costa Rica Voss 2022). We follow these authors in treating the two taxa of Marmosa as distinct species.…”

“…Marmosa (Exulomarmosa) robinsoni was noted by Voss (2022) to occur primarily in dry forest habitats ranging from western Panama to Colombia and northern Venezuela. Its presence was documented in Panama adjacent to the Costa Rican border: locality 109 of Rossi et al (2010;Finca Santa Clara, Chiriquí, Panama) is georeferenced in the USNM database as 8º51´N, 82º45´W, which would place it under 5 km from the Costa Rica border.…”