Percina nebulosa and Percina bimaculata have been considered synonyms of P. caprodes for over 130 years. The taxonomic history of P. nebulosa is complicated by the fact that the name is preoccupied by Perca nebulosa Rafinesque. Percina bimaculata Haldeman is the available and appropriate name for this species, and the Chesapeake Logperch is the proposed common name. Recent phylogenetic analyses of mitochondrial DNA gene sequences support the hypothesis that P. bimaculata is a distinct species; however, a morphological comparison between P. bimaculata and other logperch darter species has never been published. An examination of morphological characters and a new molecular phylogeny of both mitochondrial and nuclear gene sequence data support the recognition of P. bimaculata as a distinct species most closely related to P. kathae and P. austroperca. Historically, P. bimaculata was distributed in the lower Susquehanna River Basin of Pennsylvania and Maryland and the middle to lower Potomac River Basin of Maryland, Virginia and the District of Columbia, USA. The species has not been recorded from the Potomac Basin since the 1930s and is currently found only in the lower Susquehanna River Basin. The restricted geographic distribution and extirpation from the Potomac Basin indicates that P. bimaculata is an imperiled species and may warrant protection under the Endangered Species Act of 1973. The molecular phylogeny also indicates that populations recognized as P. caprodes sampled from the upper Mississippi River Basin in Illinois, Wisconsin and Minnesota are not closely related to P. caprodes populations sampled from the Ohio, Tennessee, White and Hudson river drainages.

The priority of the names Stylonurus excelsior and S. lacoanus from the Late Devonian of the eastern United States has been disputed since they were first recognized as synonyms. The genus Hallipterus was later erected for the two known specimens, and they were again separated into distinct species, based on six listed differences, seemingly resolving the priority dispute. However, four of the differences are not present or can be interpreted as ontogenetically or taphonomically induced, and the remaining two are putatively interpreted as sexually dimorphic based on comparisons with Tarsopterella, a closely related taxon. The two species are therefore synonymized again and the species epithet excelsior is considered to have priority. Advocates of both names also provided different reconstructions, mainly based on other stylonurids. Hallipterus is placed in the Hardieopteridae based on putative synapomorphies with Hardieopterus and particularly Tarsopterella, the latter also clearly a hardieopterid, and the phylogenetic position of the Hardieopteridae is discussed. Although only the original two specimens of H. excelsior are known today, as a century ago, a new reconstruction is provided, supported by phylogenetic evidence, to replace the two earlier versions.

Direct underwater observations at seamounts across the western North Atlantic basin revealed the presence of the false boarfish, Neocyttus helgae (Oreosomatidae), at depths of 915 to 1829 m. These observations extend the known range of this species across the North Atlantic basin and support the hypothesis that seamounts are stepping stones for dispersal. Fishes were associated with basalt habitats featuring corals and sponges (both nearly horizontal basalt sheets and steep cliffs) as well as depressions in sheets of basalt. These features provided refuge from flow and predators as well as immediate access to zooplankton and pelagic prey delivered by rapid currents. Encounters with fishes were primarily as single individuals or pairs. Territorial behaviors, such as raised dorsal spine and lateral display, occurred when submersible vehicles approached fish, suggesting that territorial defense is a common behavioral attribute.

Relationships within the primate order Omomyidae are assessed with dental and postcranial data, using cladistic techniques. Quantitative and qualitative characters of the dentition, mandible, maxilla and, where known, calcaneus and astragalus were evaluated for 28 omomyid species. Characters were subjected to a series of parsimony analyses including dental only, and combined dental and postcranial data, as well as evaluations with limited and expanded numbers of taxa. Trees were rooted through the use of a hypothetical outgroup taxon consisting of closely related primate and nonprimate taxa. Tarsal elements showed variability within the Omomyidae and this variability contained phylogenetic signal. When all dental and postcranial data were evaluated cladistically, omomyids prove to consist of three subfamilies: Omomyinae, Anaptomorphinae, and Microchoerinae. The omomyines consist of the tribes Washakiini, Uintaniini, Omomyini and Macrotarsiini, whereas the anaptomorphines consist of a paraphyletic Trogolemurini and Anaptomorphini. The European subfamily Microchoerinae seems more closely related to Anaptomorphinae. Species traditionally allocated to the genus Teilhardina are paraphyletic and may warrant generic distinction. Taxonomic actions include the descriptions of Arapahoviina Tornow new subtribe and Bazius Tornow new genus, and transfer of Loveinia wapitiensis Gunnell, Bartels, Gingerich and Torres, 1992 to the new genus as Bazius wapitiensis new combination.

Radiocarbon dating of the specimen YPM 40001 at the Yale Peabody Museum of Natural History, previously referred to the Pleistocene horse Equus cf. niobrarensis, determined that the specimenis less than 400 years old. The specimen is reassigned to Equus caballus.