Heliscomyids are distinguished from other geomyoid rodents by several characteristics of the skull including the fusion of three cranialforamina, elongation of the incisive foramina, and an unusual position of the mental foramen (Korth et al., 1991).
Taxonomy
Heliscomyidae is a member of the clade Geomyoidea, a group of rodents that also includes the families †Eomyidae, †Florentiamyidae, Heteromyidae, and Geomyidae. The following cladogram showing interrelationships among geomyoid families follows Korth et al. (1991):
Heteromyidae (kangaroo rats and mice, pocket mice)
References
Korth, W.W. and C. Branciforte, 2007. Geomyoid rodents (Mammalia) from the Ridgeview Local Fauna, early-early Arikareean (late Oligocene) of western Nebraska. Annals of Carnegie Museum 76(3):177-201.
Korth, W.W. and J.G. Eaton, 2004. Rodents and a marsupial (Mammalia) from the Duchesnean (Eocene) Turtle Basin Local Fauna, Sevier Plateau, Utah. Bulletin of Carnegie Museum of Natural History 36(1):109-119.
Korth, W.W., J.H. Wahlert, and R.J. Emry, 1991. A new species of Heliscomys and recognition of the family Heliscomyidae (Geomyoidea: Rodentia) Journal of Vertebrate Paleontology 11(2):247-256.
McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN0-231-11013-8
