Cylindrodontids are Eocene and Oligocene protrogomorphous rodents known from North America and Asia. Their oldest reported occurrence had been with North American Bridgerian Mysops. Earliest Wasatchian estuarine deposits at the Red Hot Truck Stop locality in the T4 sand, Tuscahoma Formation, near Meridian, Mississippi, have produced the oldest and most primitive cylindrodontids, having derived familial characters along with a generally primitive morphology. These are referred to three new species of the new genus Tuscahomys: T. medius, T. minor and T. major. These rodents inhabited an estuarine environment having paratropical climatic conditions. An additional species from the early Eocene of Wyoming, Reithroparamys ctenodactylops Korth, 1984, is referred to the new genus as Tuscahomys ctenodactylops (Korth, 1984), new combination.

The first record for the shrimp genus Aeger Münster, 1839, in America is documented by Aeger hidalguensis, new species, described from Albian–Cenomanian beds of the El Doctor Formation, Muhi Quarry, Hidalgo, Mexico. Reconsideration of Aegeridae Burkenroad, 1963, results in placement of Acanthochirana Strand, 1928, within the family. Aeger hidalguensis is associated with the palinurid lobster, Palinurus sp., which represents only the second fossil record for the genus in America. Specimens collected from the Aptian San Juan Raya Formation, Puebla, allow a more complete description of the mecochirid Meyeria pueblaensis Feldmann et al., 1995, and documentation of sexual dimorphism in the species, the first report of dimorphism in the genus.

The temnospondyl amphibian Zatrachys serratus Cope, 1878, is reported for the first time from the eastern United States on the basis of a partial skull table and isolated cranial elements from the Upper Pennsylvanian (Virgilian) of the Benwood Limestone Member of the Pittsburgh Formation, Monongahela Group, and the Lower Permian (Wolfcampian) Greene Formation, Dunkard Group, West Virginia. The partial skull table differs in several features from those of the well-preserved series of skulls of Z. serratus from the Lower Permian of New Mexico, particularly in the proportions of the postfrontal and postorbital. However, in view of the paucity of West Virginia material and the wide range of reported intraspecific variation, some possibly attributable to sexual dimorphism, and developmental changes in the cranial morphology of the New Mexico specimens, the conservative course is taken by referring the former to Z. serratus.

Known otherwise only from the Lower Permian (Wolfcampian and Leonardian) of Texas, New Mexico, and Oklahoma, the new occurrence of Z. serratus represents significant extensions of its stratigraphic and geographic ranges.

Chinese species of the crane fly genus Prionota van der Wulp, 1885, are reviewed. Prionota (Plocimas) guangdongensis, new species, is described based on males from southern China. The other previously known Chinese species, Prionota (Plocimas) magnifica (Enderlein, 1921), is re-described and a range extension noted. The new species is closely related to P. magnifica, but distinguished by configuration of the male genitalia. A key to males of the species of Prionota in China is provided.

The distribution and host associations of the ceratophyllid flea, Tarsopsylla octodecimdentata (Kolenati, 1863), are discussed. Tarsopsylla o. coloradensis (Baker, 1895) is synonymized with the nominate taxon on the grounds that the slight variations in the only anatomical feature distinguishing the two taxa, the contours of the seventh sternum in the females, is insufficient to justify their separation. The species is distributed from Great Britain, east to the western region of North America. It is a parasite of squirrels belonging to the genera Sciurus Linnaeus, 1758, Tamiasciurus Trouessart, 1880, and Glaucomys Thomas, 1908. Judging from the lack of a metapleural arch it is thought to be a “nest flea.”

Ten species of geomyoid rodents are recognized from the early-early Arikareean Ridgeview local fauna of Nebraska: three heliscomyids, four florentiamyids, one heteromyid, and two species of the probable geomyid Tenudomys Rensberger, 1973. Two new genera are described, the heliscomyid Tylionomys and a harrymyine heteromyid Proharrymys. Two previously described Arikareean species are referred to Proharrymys: Heliscomys schlaikjeri Black, 1961 and Proheteromys fedti Macdonald, 1963 (new combinations). Four new species are named: the heliscomyids Heliscomys macdonaldi and Tylionomys voorheisi, the heteromyid Proharrymys wahlerti, and the probable geomyid Tenudomys ridgeviewensis.

Heliscomyids are more diverse in the Ridgeview local fauna than in any other Arikareean fauna in North America. This increases the known diversity of this family during a time interval from which only a single species was previously recognized. Larger florentiamyids are poorly represented in the fauna, but the sample is large enough to demonstrate that Florentiamys kennethi Wahlert, 1983 is a junior synonym of F. tiptoni (Macdonald, 1970). A large sample of the small florentiamyid Kirkomys Wahlert, 1984 is sufficient to demonstrate that Proheteromys nebraskensis Wood, 1937 is synonymous with Kirkomys milleri Wahlert, 1984, resulting in the new combination Kirkomys nebraskensis.

The only heteromyid in the fauna, P. wahlerti, is believed to be the basal harrymyine from which the Hemingfordian Harrymys can be derived.