Donald E. Russell

Origin of whales in epicontinental remnant seas: new evidence from the early eocene of pakistan.

Pakicetus inachus from the early Eocene of Pakistan is the oldest and most primitive cetacean known. The dentition of Pakicetus resembles that of carnivorous mesonychid land mammals as well as middle Eocene cetaceans. The otic region of the cranium lacks characteristic specializations of whales necessary for efficient directional hearing under water. Pakicetus occurs with a land-mammal fauna in fluvial sediments bordering epicontinental Eocene remnants of the eastern Tethys seaway. Discovery of Pakicetus strengthens earlier inferences that whales originated from terrestrial carnivorous mammals and suggests that whales made a gradual transition from land to sea in the early Eocene, spending progressively more time feeding on planktivorous fishes in shallow, highly productive seas and embayments associated with tectonic closure of eastern Tethys.

Dentition and systematic relationships of Altanius orlovi (Mammalia, Primates) from the early Eocene of Mongolia

Abstract New specimens of Altanius orlovi are described from the type area, Tsagan-Khushu, in Mongolia. These include the first dentary preserving alveoli for anterior teeth, which show the lower dental formula of Altanius to have been 2.1.4.3. Lower incisors were small, equal in size, and nearly vertical in emplacement. The lower canine alveolus is larger than alveoli for the incisors and larger than that for P 1 . Alveoli show P 1 to have been single-rooted and P 2 double-rooted. Upper premolars lack a paraconule, and M 1–2 have a short Nannopithex -fold rather than a full postprotocingulum joining the posterior cingulum. Altanius is one of the smallest primates known. Morphological comparisons with Teilhardina and Cantius indicate that Altanius is more generalized and primitive than other Omomyidae or Adapidae. Altanius is clearly one of the most primitive primates known to date.

Further data on Prokennalestes (Mammalia, Eutheria inc. sed.) from the Early Cretaceous of Mongolia

Four new incomplete lower jaws of Prokennalestes are described. bringing new data for establishing the primitive cutherian dental formula and its evolution in later placentals, as well as the possible relationships of the genus.

Presence of the genus Afrodon [Mammalia, Lipotyphla (?), Adapisoriculidae] in Europe; new data for the problem of trans-Tethyan relations between Africa and Europe around the K/T boundary

The species Adapisoriculus? germanicus Russell 1964 from the Late Palaeocene of Walbeck (G.D.R.) is recognized, after its revision, at Cernay (late Palaeocene of France) and referred to Afrodon Gheerbrant 1988, a genus recently described from the late Palaeocene of Morocco. The affinity between the European species and A. chleuhi, from Morocco, implies a trans-Tethyan terrestrial exchange between Africa and Europe at about the time of the deposition of the Walbeck fossiliferous sediments (corresponding to the earliest Thanetian of marine depositional areas) or well prior to it. Comparison of the two species also permits an emended diagnosis of the genus to be proposed.

The paroxyclaenidae (Mammalia) and a new form from the early Eocene of Palette, France

KurzfassungEine neue Gattung und Art der Paroxyclaenidae,Merialus martinae, wird beschrieben; dabei wird die Familie revidiert und in zwei Subfamilien, die Paroxyclaeninae und die Merialina’e, nov., aufgeteilt. Die zwei Arten vonDyspterna werden zwei Gattungen zugewiesen, von denenEuhooke- ria neu ist. Die Subfamilie Dyspterninae Kretzoi, 1943, wird wieder aufgestellt, umDyspterna woodi,Cryptopithecus undKochictis zusammenzufassen; die Subfamilie wird zu den Pantolestidae gestellt.Vulpavoides wird als valide Gattung angesehen; sie enthält »Russellites«simplicidens. V. vanvaleni n. sp. wird von Bouxwiller beschrieben. Die GattungenKiinkerishella undDulcidon und mögliche Beziehungen zwischen den Ptolemaiidae und den merialinen Paroxyclaeniden werden diskutiert.AbstractA new genus and species of the Paroxyclaenidae is described,Merialus martinae, and the family is reviewed and divided into two subfamilies, the Paroxyclaeninae and the Merialinae, new. The two species ofDyspterna are attributed to two genera, of whichEuhookeria is new; Dyspterninae Kretzoi, 1943, is resurrected to includeDyspterna woodi, Cryptopithecus andKochictis; the subfamily is referred to the Pantolestidae.Vulpavoides is considered valid and includes“Russellites”simplicidens;V. vanvaleni n. sp. is described from Bouxwiller.Kiinkerishella andDulcidon are discussed, as are possible relationships between the Ptolemaiidae and the Merialine paroxyclaenids.

Extension of dyspternine Pantolestidae (Mammalia, Cimolesta) in the Early Oligocene of Mongolia

Abstract A new dyspternine Pantolestidae, Gobiopithecus khan nov. gen., nov. sp., is described from the early Oligocenelocality of Khoer Dzan, Gobi Desert, Mongolia. Affinity of the new taxon to Kiinkerishella from Kazakhstan and to the European dyspternines, particularly Dyspterna and Cryptopithecus , is proposed. The evolutionary and geographic development of the group is considered.

A new middle Eocene insectivore from the Mongolian People's Republic

Abstract A new genus and species, Bogdia orientalis , (Mammalia,Proteutheria, Pantolestidae) is described from the middle Eocene site of Tsagan-Khutel, from the valley of Lakes of the Peoples Republic of Mongolia. It is the first pantolestid species described from Asia.

Critique of certain Eocene Primate taxa

Abstract All Paleogene primates are plagued by uncertaintiesconcerning their classification and phyletic relationships. Purgatorius is taken as an example of a primitive primate and on this basis two genera, Donrussellia and Teilhardina are analyzed. Donrussellia is relegated to subgeneric status within Teilhardina and the included species are considered possibly to have been near the ancestry of the omomyid-adapid complex. The North American species Teilhardina americana is the most primitive omonyid presently known from that continent.

Comments on mammalian paleontologicstratigraphy and geochronology; Eocene stages and mammal ages of Europe and North America

Abstract 1. In terrains and intervals such as the nonmarine paleogene in Europe where fossil-mammal samples are found mostly in isolated pockets or lenses lacking stratigraphic contiguity with other samples of fossils, relative or ordinal dating by stage-of-evolution or phyletic position or niveau repere of the paleospecies (i. e., the phyletically controlled index taxon or association of taxa) remains the best technique for applying paleontology to chronostratigraphy and geochronology. 2. In terrains and intervals such as many Tertiary basins of nonmarine sedimentation in North America where the stratigraphic relationships between fossil-mammal samples can be analyzed (i. e., measured and oriented spatially) with necessary precision, the chronozone, based on joint occurrence (overlapping stratigraphic ranges) of selected paleospecies, makes the most useful and most refined unit for geochronologic correlation. 3. All paleontological techniques for dating are basically empirical and should be reviewed and revised constantly. There is a limit to paleontological resolution in chronostratigraphy and geochronology. 4. The Sparnacian Substage is a valid and useful chronostratigraphic unit and should be perpetuated, despite the fact that it is difficult to correlate with marine stratigraphic sections.

Un primate nouveau du Paleocene superieur de France

Resume Description de Berruvius gingerichi n. sp., nouveau primate microsyopide uintasoricine du Paleocene superieur de Cernay-les-Reims. Comparaison detaillee de cette espece avec le genre nord-americain Navajovius; discussion de ses affinites.