Late Pleistocene Shasta Ground Sloth (Xenarthra) Dung, Diet, and Environment From the Sierra Vieja, Presidio County, Texas

Abstract

We present new information about the Late Pleistocene Shasta ground sloth (Nothrotheriops shastensis). Spirit Eye Cave in the Sierra Vieja along the Rio Grande provides the newest evidence that the Shasta ground sloth inhabited further south in the mountains of the southwestern Trans-Pecos, Texas, than has been previously documented. The cave is one of only twelve known Nothrotheriops dung localities. During excavation of the cave, packrat middens and sloth dung were discovered. Two areas within the cave provide radiocarbon dated ground sloth dung and packrat midden macrobotanical remains which permit the reconstruction of the sloth diet and local biotic habitat at 30,800 and 12,900 calibrated YBP. The local community at 30,800 calibrated years ago was a pinyon-juniper woodland with yucca, sandpaper bush, globemallow, cactus, and barberry in the understory based on the packrat midden from the cave. The dung contents indicate that the diet of the sloth included C3 and C4 grasses along with Agave. Data for the local vegetation community and sloth diet from 12,900 years ago indicate that during this late glacial time, the region was still a pinyon-juniper woodland but also contained Celtis, Quercus, and Larrea, among other taxa.

Metagenomic analysis of coprolites from three Late Pleistocene megaherbivores from the Southwestern United States

“…Since the early twentieth century, the macrobotanical, microhistological and pollen samples found within these coprolites and middens have been used to reconstruct the environment of the Southwest USA, and in the case of the fecal matter, the diet of the originator (Eames 1930; Martin, Sabels, and Shutler 1961; Hansen 1978; Thompson et al 1980; Martin, Thompson, and Long 1985; Mead, O’Rourke, and Foppe 1986; Mead et al 1987; Schmidt, Duszynski, and Martin 1992). Later genetic analyses of the Colorado Plateau coprolite specimens have focused on amplifying and sequencing gene fragments from the host and dietary plants it consumed (Hofreiter et al 2000; Poinar et al 1998; Greenwood et al 2001; Thompson et al 1980; Mead, Schroeder, and Yost 2021). Poinar et al (1998) identified boluses found in Gypsum Cave, Nevada, as originating from the Xenarthra taxon and subsequently assigned them to the Shasta ground sloth by sequencing multiple fragments of mitochondrial rDNA genes, as well as amplifying a fragment of the rbcL gene to identify the dietary plant families (Poinar et al 1998; Hofreiter et al 2000).…”

First Shasta Ground Sloth (Nothrotheriops; Xenarthra) from the Eastern Great Basin, Nevada

“…Overall, Nothrotheriops shastensis was the most xeric-adapted of all North American ground sloths based on the dietary reconstructions from plants obtained from dry-preserved dung found in multiple caves in the Southwest (Laudermilk and Munz 1938, Hansen 1978, Thompson et al 1980, Poinar et al 1998, Mead et al 2021, McDonald 2022). However, it was clearly able to inhabit less xeric habitats and process different vegetation based on its co-occurrences with other ground sloths (e.g., Megalonyx and Paramylodon) in southern, more coastal Califor-nia (McDonald 2021, Fig.…”

“…Map of the greater Intermountain West showing the approximate hydrographic Great Basin boundary with an inset of the pluvial Lake Bonneville basin. Localities with Nothrotheriops shastensis are shown as black dots (McDonald and Jefferson 2008, Mead et al 2021). The location of Smith Creek Cave is indicated with a black triangle.…”