Gradual phyletic evolution at the generic level in early Eocene omomyid primates

Analysis of dental morphology in over 600 stratigraphically controlled specimens of tarsier-like primates from early Eocene strata in Bighorn Basin, Wyoming, provides important new data for understanding the tempo and mode of evolution in primates

Patterns of Dental Evolution in Early Eocene Anaptomorphine Primates (Omomyidae) From the Bighorn Basin, Wyoming

ABSTRACT--The subfamily Anaptomorphinae contains the oldest and most generalized members of the tarsier-like primates and is the basal group of the extinct family Omomyidae. The best and most continuous record of anaptomorphine history is from rocks of early Eocene (Wasatchian) age in the Bighorn Basin of northwest Wyoming where eight genera and 14 species are recognized. Three of these species are new (Teilhardina crassidens, Tetonius matthewi, Absarokius metoecus), and four other new species are described from elsewhere (Tetonius mckennai, Absarokius gazini, A. australis, Strigorhysis huerfanensis). Teilhardina tenuicula and Absarokius nocerai are new combined forms. Absarokius noctivagus is considered to be a synonym of A. abbotti, and Mckennamorphus is a synonym of Pseudotetonius

Patterns of Dental Evolution in Early Eocene Anaptomorphine Primates (Omomyidae) From the Bighorn Basin, Wyoming

ABSTRACT--The subfamily Anaptomorphinae contains the oldest and most generalized members of the tarsier-like primates and is the basal group of the extinct family Omomyidae. The best and most continuous record of anaptomorphine history is from rocks of early Eocene (Wasatchian) age in the Bighorn Basin of northwest Wyoming where eight genera and 14 species are recognized. Three of these species are new (Teilhardina crassidens, Tetonius matthewi, Absarokius metoecus), and four other new species are described from elsewhere (Tetonius mckennai, Absarokius gazini, A. australis, Strigorhysis huerfanensis). Teilhardina tenuicula and Absarokius nocerai are new combined forms. Absarokius noctivagus is considered to be a synonym of A. abbotti, and Mckennamorphus is a synonym of Pseudotetonius

Dentition of the Early Eocene primates Niptomomys and Absarokius

The mandibular dentition of Niptomomys doreenae was previously known only from an edentulous mandible preserving alveolae for all teeth, and jaw fragments preserving P4 and M1-3. A new mandible of Niptomomys is described here which preserves an enlarged, lanceolate lower incisor and a small, blunt, single-rooted P3. The incisor morphology confirms placement of Niptomomys in the Family Microsyopidae. The presence of a single-rooted P3 invalidates the previous interpretation of the lower dental formula. Comparison with the related early primates Navajovius, Palaechthon, Plesiolestes and Uintasorex shows the lower dental formula of Niptomomys to be 1.1.3.3. The total number of teeth in the mandible of Absarokius was previously determined to be eight (except for a single specimen of Absarokius near A. abbotti which Gazin, 1962, suggested might possibly have nine). Two mandibles of A. abbotti described here clearly had nine teeth and a lower 2 dental formula of 2.1.3.3. The upper canine and P2 of this species are also described here for the first time. Comparison of the new specimens of A. abbotti with the later A. noctivagus noceri demonstrates that the tooth previously interpreted in the latter taxon as P2 is in fact the canine, thus the lower dental formula of A.n. noceri is 2.1.2.3, not 1.1.3.3. Absarokius abbotti, with a dental formula of I2?2, C11, P33, M33 seems clearly to be derived from a species of Tetonius

THE ORIGIN OF \u3ci\u3eCHUBUTOLITHES\u3c/i\u3e IHERING, ICHNOFOSSILS FROM THE EOCENE AND OLIGOCENE OF CHUBUT PROVINCE, ARGENTINA

ABSTRACT-The distinctive trace fossil Chubutolithes gaimanensis n. ichnosp. occurs in Casamayoran (early Eocene) and Colhuehaupian (late Oligocene) alluvial rocks of the Sarmiento Formation in eastern Chubut Province, Argentina. Though known for nearly 70 years, its origin has remained obscure. Examination of new specimens and comparisons with modem analogs demonstrate that specimens of Chubutolithes represent the fossil nests of a mud-dauber (Hymenoptera: Sphecidae). Virtually identical nests are constructed today by mud-daubers in areas as disparate as southern Santa Cruz Province, Argentina, and Nebraska, confirming that quite similar trace fossils can be produced by several different taxa in a higher taxonomic clade. No satisfactory ethological term exists for trace fossils that, like Chubutolithes, were constructed by organisms above, rather than within, a substrate or medium. The new term aedificichnia is proposed. Chubutolithes occurs in alluvial paleosols and is associated with a large terrestrial ichnofauna. These trace fossils include the nests of scarab beetles, compound nests of social insects, and burrows of earthworms

On the Classification of the Early Tertiary Erinaceomorpha (Insectivora, Mammalia)

Definitions are provided for three Early Tertiary families of Erinaceomorpha. The family Dormaaliidae includes Dormaalius, Macrocranion, Scenopagus, Ankylodon, Crypholestes, Sespedectes, and Proterixoides

An unusual new mammal from the Early Eocene of Wyoming

A newly discovered maxillary dentition from the Early Eocene rocks of the Bighorn Basin, Wyoming, is unlike that of any mammal previously known from this intensively collected region. It represents a new genus and species, here named Alocodon atopum. The new form bears superficial resemblance to various mammals, but specific features suggest a real relationship only to palaeanodonts, particularly Tubulodon taylori, aformof uncertain family ties, and the epoicotheriid Pentapassalus pearcei. The most significant features of the molars are their cylindrical shape, their odd cusp arrangement, and their reduced enamel. Because of its similarity to Tubulodon, Alocodon is tentatively allocated here to the Epoicotheriidae (Pholidota, Palaeanodonta). If correctly assigned, it represents the oldest known member of this poorly represented family and the first from the Bighorn Basin

A frotarsius chatrathi, first tarsiiform primate (? Tarsiidae) from Africa

Tarsiiform primates have long been regarded as a Laurasian group, with an extensive fossil record in the Eocene of North America and EuropeI and two important but less well-known records from Asia