Holmesina

Holmesina is an extinct genus of pampathere, a group of armadillo-like xenarthrans that were distantly related to extant armadillos. Like armadillos, and unlike the other extinct branch of megafaunal cingulates the glyptodonts, the shell was made up of flexible plates which allowed the animal to move more easily.

File:Holmesina occidentalis.jpg

Holmesina occidentalis

File:Holmesina floridanus life reconstruction.jpg

Life reconstruction of Holmesina floridanus and size comparation.

Holmesina individuals were much larger than any modern armadillo: They could reach a length of , and a weight of , while the modern giant armadillo does not attain more than .

Taxonomy

Joseph Leidy initially described Holmesina fossils from Florida as Glyptodon septentrionalis in 1889. However, shortly after a close relationship with the pampatheriids was realized, wherein the finds were reassigned to the South American Pampatherium ("Chlamytherium") humboldtii, therein revised to its own species, Chlamytherium septentrionalis, by Elias Howard Sellards in 1915. After additional fossils from Texas were described, George Gaylord Simpson assigned the finds to its own genus, Holmesina, in 1930.

Distribution

They traveled north during the faunal interchange, and adapted well to North America, like the ground sloths, glyptodonts, armadillos, capybaras, and other South American immigrants. During the Late Pleistocene, Holmesina dispersed from North America back into South America, as evidenced by the morphological similarity of Late Pleistocene species in South America. Their fossils are found from Brazil to the United States, mostly in Texas and Florida.

Diet

Holmesina species were herbivores that grazed on coarse vegetation; armadillos are mostly insectivorous or omnivorous. H. paulacoutoi was a generalist plant-eater but had a preference for C₄ plants.

Palaeopathology

Three H. cryptae specimens have been described bearing evidence of bacterial and fungal infections, along with sand flea ectoparasitism.

Further reading

• J. C. Cisneros. 2005. New Pleistocene vertebrate fauna from El Salvador. Revista Brasileira de Paleontologia 8(3):239-255
• P. J. Gaudioso, G. M. Gasparini, and R. M. Barquez. 2016. Paleofauna del Pleistoceno de Termas de Rio Hondo, Santiago del Estero, Argentina. Ameghiniana 53(6):54-54
• J. I. Mead, S. L. Swift, R. S. White, H. G. McDonald, and A. Baez. 2007. Late Pleistocene (Rancholabrean) glyptodont and pampathere (Xenarthra, Cingulata) from Sonora, Mexico. Revista Mexicana de Ciencias Geológicas 24(3):439-449