Geomyoid rodents

20 p. : ill. ; 26 cm.Includes bibliographical references (p. 18-20)."Analysis of cranial and mandibular morphology, especially the foramina and structures relating to the masticatory musculature, supports monophyly of the living Heteromyidae. The family includes two major divisions, the Heteromyinae on the one hand, and the Perognathinae and Dipodomyinae on the other. Derived features of Schizodontomys suggest that the genus may be an early member of the Dipodomyinae. The Heteromyidae and Geomyidae, containing only the Geomyinae, share common ancestry. The Entoptychidae are tentatively placed as the sister group of these two families; the Florentiamyidae appear to be the earliest known branch of the geomyoid clade. The Geomyoidea, which includes these families, and the extinct Eomyoidea comprise the infraorder Geomorpha. A classification of the Geomorpha that reflects these phylogenetic hypotheses is presented"--P. [1]

Cranial foramina and relationships of the Eomyoidea (Rodentia, Geomorpha) : skull and upper teeth of Kansasimys. American Museum novitates ; no. 2645

16 p. : ill. ; 26 cm.Includes bibliographical references (p. 15-16)."Derived characters of the incisive foramen, infraorbital canal, sphenopalatine foramen, transvere canal, sphenopterygoid foramen, carotid canal, and temporal foramina are shared by eomyids and geomyoids (Geomyidae and Heteromyidae). Three of these characters are shared with myoxoids, dipodoids, and muroids. These facts support the hypothesis that eomyids and geomyoids had common ancestry in a stem species from which no other rodent groups are descended. The family Eomyidae is raised to equal rank, Eomyoidea. Likewise, the inclusive infraorder Geomorpha and rodents traditionally considered myomorphs shared unique common ancestry and are placed together in the suborder Myomorpha. Yoderimys and Kansasimys are primitive in the infraorbital canal and lack of interorbital foramen, but Kansasimys shares derived tooth crown morphology with other eomyoids. The skull of Kansasimys is distinguished by large size and by peculiarities of the premaxillary-maxillary suture, temporal-supraorbital crests, and occiput; the teeth resemble those of Adjidaumo"--P. [1]

Cranial foramina and relationships of Eutypomys (Rodentia, Eutypomyidae). American Museum novitates ; no. 2626

8 p. : ill. ; 26 cm.Includes bibliographical references (p. 7-8)."Derived characters of the sphenopalatine, interorbital, and dorsal palatine foramina are shared by the Eutypomyidae and Castoridae. These support the hypothesis that the two families had common ancestry in a stem species from which no other rodent groups are descended. The two families may be included in a monophyletic superfamily, Catoroidea"--P. [1]

Cricetops and Lophiomys

15 p. : ill. ; 26 cm.Includes bibliographical references (p. 14-15)."Cricetops, an extinct cricetid from the mid-Oligocene of Mongolia and Kazakhstan, and Lophiomys, a peculiar cricetid living in eastern Africa, share dorsoventral expansion of the jugal bone and enclosure of fossettids in the transverse crests of M[subscript 1]. They are proposed as each other's closest relative and inlcuded in the subfamily Lophiomyinae. Emphasis on transverse wear is hared by these genera and the living Cricetinae: Cricetulus, Phodopus, Mesocricetus, and Cricetus. The two subfamilies are considered closest relatives and placed in the muroid family Cricetidae. Cricetops and the living cricetines are chiefly northern Asiatic groups. Immigration to Africa from Asia is proposed for the ancestors of Lophiomys"--P. [1]

Auditory region in Paramys copei

16 p. : ill. ; 26 cm.Includes bibliographical references (p. 14-16).The morphology of the external surface of the petrosal and its junction with the basioccipital in Paramys copei is described. Comparison with an outgroup of the Cretaceous Vincelestes and Recent Didelphis and Solenodon reveals that the auditory region retains many primitive features. The Eocene paramyines from North America show only slight differences. Sciuravus is set apart by the lack of a ventral petrosal sinus canal between the petrosal and basioccipital and by the facial nerve and stapedial artery sharing a common foramen in the petrosal. European theridomyids, too, are not as primitive as Paramys but share with it and Sciuravus a ridge on the promontorium that separates the transpromontorial continuation of the internal carotid artery from the origin of the tensor tympani muscle. Twelve characters of the auditory region are analyzed and summarized in a data matrix for use in future studies. Relative primitiveness of the auditory region in all of these Eocene rodents suggests that derived characters in later rodent taxa may represent intraordinal relationships but only homoplasy with nonrodents

Eomyid rodents

12 p. : ill. ; 26 cm.Includes bibliographical references (p. 12)."The three-layered Schmelzmuster in lower incisors of eomyid rodents is described. It shows that even the specialized uniserial enamel in rodents can be further modified. The portio interna in eomyids is divided into two parts, and the Hunter-Schreger bands are longitudinal rather than transverse as is common in rodents. The inner part of the portio interna shows a type of uniserial enamel found in myomorphs in which all three axes are strengthened by fibers. The outer part resembles uniserial bands in sciurids, because crystallites of interprismatic matrix are parallel to the prisms. This complex Schmelzmuster and a longitudinal thickening of the enamel near the lateral side of the incisor are unique, derived characters of the Eomyidae"--P. [1]

Geomyoid rodent

6 p. : ill. ; 26 cm.Includes bibliographical references (p. 6)."Jimomys labaughi is a new genus and species of rodent of early Barstovian age. Morphology of the lower jaw, dentition, and incisor enamel indicates that the form is a geomyid. The crown pattern of the cheek teeth appears to be derived independently from one primitive to the superfamily. A species from the John Day Formation, Florentiamys lulli (Wood, 1936), has similar tooth morphology and is transferred to Jimomys"--P. [1]

Contributions in honor of Guy G. Musser.

450 p. : ill. (some col.), maps ; 26 cm. "Issued December 15, 2009." Includes bibliographical references.Contents: They sort out like nuts and bolts : a scientific biography of Guy G. Musser / Michael D. Carleton -- Taxonomy, distribution, and natural history of the genus Heteromys ‪(‬Rodentia: Heteromyidae‪)‬ in central and eastern Venezuela, with the description of a new species from the Cordillera de la Costa / Robert P. Anderson and Eliécer E. Gutiérrez -- Review of the Oryzomys couesi complex ‪(‬Rodentia: Cricetidae: Sigmodontinae‪)‬ in western Mexico / Michael D. Carleton and Joaquin Arroyo-Cabrales -- The antiquity of Rhizomys and independent acquisition of fossorial traits in subterranean muroids / Lawrence J. Flynn -- A new species of Reithrodontomys, subgenus Aporodon ‪(‬Cricetidae: Neotominae‪)‬, from the highlands of Costa Rica, with comments on Costa Rican and Panamanian Reithrodontomys / Alfred L. Gardner and Michael D. Carleton -- Phylogenetic relationships of harpyionycterine megabats ‪(‬Chiroptera: Pteropodidae‪)‬ / Norberto P. Giannini, Francisca Cunha Almeida, and Nancy B. Simmons -- A new genus and species of small ‪"‬tree-mouse‪"‬ ‪(‬Rodentia, Muridae‪)‬ related to the Philippine giant cloud rats / Lawrence R. Heaney, Danilo S. Balete, Eric A. Rickart, M. Josefa Veluz, and Sharon A. Jansa -- Biodiversity and biogeography of the moss-mice of New Guinea : a taxonomic revision of Pseudohydromys ‪(‬Muridae: Murinae‪)‬ / Kristofer M. Helgen and Lauren E. Helgen -- Systematic revision of sub-Saharan African dormice ‪(‬Rodentia: Gliridae‪)‬. Part 2, Description of a new species of Graphiurus from the central Congo Basin, including morphological and ecological niche comparisons with G. crassicaudatus and G. lorraineus / Mary Ellen Holden and Rebecca S. Levine -- Descriptions of new species of Crocidura ‪(‬Soricomorpha: Soricidae‪)‬ from mainland Southeast Asia, with synopses of previously described species and remarks on biogeography / Paulina D. Jenkins, Darrin P. Lunde, and Clive B. Moncrieff -- The six opossums of Félix de Azara : identification, taxonomic history, neotype designations, and nomenclatural recommendations / Robert S. Voss, Philip Myers, François Catzeflis, Ana Paula Carmignotto, and Josefina Barreiro -- Skull and dentition of Willeumys korthi, nov. gen. et sp., a cricetid rodent from the Oligocene ‪(‬Orellan‪)‬ of Wyoming / John H. Wahlert

The Harrymyinae, a new heteromyid subfamily (Rodentia, Geomorpha) : based on cranial and dental morphology of Harrymys Munthe, 1988. American Museum novitates ; no. 3013

23 p. : ill. ; 26 cm.Includes bibliographical references (p. 18-20

Kirkomys, a new florentiamyid (Rodentia, Geomyoidea) from the Whitneyan of Sioux County, Nebraska. American Museum novitates ; no. 2793

8 p. : ill. ; 26 cm.Includes bibliographical references (p. 7-8)."Kirkomys milleri, a new genus and species of florentiamyid, is described from a partial skull. Participation of the palatine in the lateral wall of the anterior-alar fissure and long entostyle in the upper molars are derived characters shared with other florentiamyids. However, frontal flanges over the orbits are lacking; the position and size of certain foramina and the morphology of the premolar parallel conditions in living geomyoids and are derived relative to those in Florentiamys and Sanctimus. Kirkomys probably represents a florentiamyid lineage that is separate from these two genera. Heliscomys schlaikjeri is transferred to Kirkomys on evidence of dental morphology. Wear on the upper teeth indicates propalinal chewing. Certain facets show that lower teeth were widened by buccal styles. The crown pattern of the upper cheek teeth is similar to that of Perognathus. However, the teeth of Kirkomys, like those of other florentiamyids, are bunodont and broadened by an anteroposteriorly elongated entostyle. The diet was probably less abrasive than that of Perognathus"--P. [1]