Rodents from the Zia Sand Miocene of New Mexico
1975
Gawne, Constance Elaine
"Rodents from the ?latest Arikareean-medial Hemingfordian faunas from the Zia Sand include one mylagaulid and several geomyoids. The Standing Rock local fauna is considered earliest Hemingfordian or latest Arikareean; its three geomyoid rodents, Proheteromys cejanus, new species, P. aff. floridanus (Heteromyinae), and Ziamys tedfordi, new genus and species (Geomyinae) are consistent with such an age but have little value in detailed correlation. Ziamys combines geomyine palatal and rostral structure with pleurolicine-like cheek teeth, which contrast strongly with those of Dikkomys. Ziamys indicates that the Geomyinae evolved from among the Pleurolicinae, but also resembles species of Gregorymys sufficiently to suggest an origin near the point of division of Pleurolicinae and Entoptychinae. The Blick local fauna of medial Hemingfordian age includes a pleurolicine most nearly resembling the Arikareean Pleurolicus sulcifrons. The specimen includes dP[superscript 4] [subscript 4], not known for Pleurolicus; these teeth resemble those of entoptychines. A similar dP[superscript 4] has been described from the Hemingfordian Quarry A, Martin Canyon local fauna. A heteromyid species is represented by a specimen resembling Proheteromys and another resembling Mookomys; it may lie near the point of origin of the perognathinae. Mesogalus aff. vetus, from Jeep Quarry, is morphologically intermediate between M. praecursor from the marsland Formation and M. vetus of the Sheep Creek local fauna, and supports an age estimate of late medial Hemingfordian for the Jeep local fauna"--P. [1].
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