Philip Hershkovitz

The Recent Mammals of the Neotropical Region: A Zoogeographic and Ecological Review

The Neotropical Region, which is defined on the basis of its living mammals, is comprised of the Brazilian, Patagonian, and West Indian Subregions. The Middle American Province of the Brazilian Subregion was the primary center of origin, evolution, and dispersal for mammals now living in continental South America. The West Indies also derived its fauna from Middle America, and perhaps also from South America. Faunal interchange between these regions must have taken place since the Middle Tertiary, at the latest. By the time the Isthmian land bridge between Middle and South America was completed during the Pliocene-Pleistocene transition, nearly all modern genera of Neotropical mammals were already differentiated within their present geographic ranges. Five faunal strata of Neotropical mammals are identified on the basis of postulated centers of origin of the ancestral stock, dispersal routes of colonizers, known grades of differentiation of living descendents, and the meager fossil evidence. The living fauna is classified ecologically as sylvan, pastoral, fluviatile, and versatile. The faunas of widely separated and ecologically contrasting biotic areas are then described, and some of the biological factors controlling evolution and dispersal are briefly discussed.

Taxonomy of squirrel monkeys genus Saimiri (Cebidae, platyrrhini): A preliminary report with description of a hitherto unnamed form

Two groups of squirrel monkeys, genus Saimiri, are distinguished by external characters. The first, or Roman type, contains Saimiri boliviensis of upper Amazonia south of the Rio Marañón‐Amazonas, with two subspecies of which S. boliviensis peruviensis is described as new. The second group, or Gothic type, contains three species: Saimiri sciureus with four subspecies distributed over much of tropical South America, Saimiri ustus of Brazil between the south bank Amazonian Rios Purús and Xingu, and S. oerstedi isolated on a Pacific coastal area straddling Costa Rica and Panamá. The geographic range of S. sciureus overlaps parts of those of S. ustus and S. boliviensis. Incomplete karyotypic data indicate that the diploid number of chromosomes for the genus is 44. Geographic variation is characterized by reduction from seven to six or five paired acrocentric autosomes through pericentric inversion with reciprocal increase in number of paired submetacentric or subtelocentric autosomes. Geographic distribution, behavior, sexual dimorphism including dichromatism, and hybridization are discussed. Ventral guide hairs for orientation of subprecocial newborn toward the maternal mammae are described. Distinguishing characters of species and subspecies are provided in a key. The taxons are listed with the taxonomy of each discussed, their geographic distribution plotted and mapped.

A New Genus of Late Oligocene Monkey (Cebidae, Platyrrhini) with Notes on Postorbital Closure and Platyrrhine Evolution

The platyrrhine Homunculus harringtoni Rusconi, 1933, of the Patagonian Late Oligocene, known from a skull fragment, is designated type of new genus Tremacebus, new subfamily Tremacebinae, family Cebidae. Comparisons are made with contemporaneous Dolichocebus Kraglievich, early Miocene Homunculus, and Recent platyrrhines, mainly AotusCallicebus, and Saimiri. Notable characters of Tremacebus include Callicebus-size skull with short face, braincase steeply vaulted, posterior occipital plate and foramen magnum directed more nearly backward than downward, orbits oriented fronto-laterally, interorbital region wide, muzzle broad, zygomatic arch relatively long, dental arch more nearly U- than V-shaped, occlusal surface of dental row moderately curved. Outstanding is the extremely large orbitotemporal opening (basis for generic name) which resolves one of two main cranial characters separating platyrrhines from tarsioids. The two halves of missing Tremacebus mandible are presumably synostosed at symphysis menti as in all platyrrhines, but in no tarsioid. Morphological stages and grades in evolution of primate postorbital closure are described and figured. Platyrrhine origin, history, and relationship are briefly discussed within the framework of continental drift. The Homunculidae are defined and a systematic arrangement is proposed for all New World primate families and genera known from Mexico southward.

The Species of Sakis, Genus Pithecia (Cebidae, Primates), with Notes on Sexual Dichromatism

Recognized species of sakis, South American monkeys of genus Pithecia (Cebidae), are P. hirsuta Spix, P. monachus E. Geoffroy, P. albicans Gray, P. pithecia Linnaeus. Evolutionary stages in sexual dichromatism in sakis and other primates are noted.

Cerebral Fissural Patterns in Platyrrhine Monkeys

Evolution of cerebral fissural patterns pursues the same pathway in all primates. As body mass increases, the brain becomes larger, the cerebral fissures more numerous. All primary fissures of a given locus are homologous, and each fissure arises in the same order in all phyletic lines. Implications of cerebral fissural patterns in platyrrhine evolution and systematics are discussed.

Comments on the taxonomy of Brazilian marmosets (Callithrix, Callitrichidae).

The taxonomic appraisal of Brazilian marmosets, genus Callithrix, by Coimbra-Filho and Mittermeier is critically examined. It is shown that their assertions are not supported by the evidence.

The Brazilian rodent genus Thalpomys (Sigmodontinae, Cricetidae) with a description of a new species

Thalpomys Thomas, endemic to the cerrado of central Brazil, is a strikingly distinct genus of the akodont assemblage (Sigmodontinae, Cricetidae, Rodentia). The genus and the two included species, one new, are described and compared. The validity of the names of the genus and type species T. lasiotis Thomas, 1916, is elucidated. The little known about habitat, relative population numbers, and karyotype is included.

Notes on American Monkeys of the Genus Cebus

Critical remarks by the late Dr. G. H. H. Tate (1954) regarding my identification of Cebus apella Linnaeus seem to be founded on a misunderstanding of the significance of certain external characters of the species and a misinterpretation of the terminology used for indicating those characters. The original figure and description of Simia apella Linnaeus, 1766, reproduced by Tate (1954, Pl. 1) refers quite correctly to the animal all authors have held to be Cebus apella . My 1949 characterization of Cebus apella is based on the same figure as well as on large series of specimens from various museums and others accumulated by Dr. Remington Kellogg for his study of the species Cebus apella . The basis for the difference of opinion is that Tate (1954: 415) points to one animal but holds in mind a totally different one when he states that C. apella is “an uncrested species and that the name appeared to be applicable to the common gray-brown species inhabiting the Guiana region, which Hershkovitz (p. 332 [1949]) refers to C. nigrivittatus castaneus .” Tate goes on to say (p. 417) that comparisons of the picture of the original C. apella “with the apella of Hershkovitz (1949: 325, Fig. 52) will, I think, forever still any doubt that Linnaeus had before him an uncrested Cebus monkey when he described Simia apella .” Tates concept of crested and uncrested species of Cebus is based solely on cranial characters and primarily on the presence or absence of a sagittal crest on the skull of the adult male (cf. Tate, 1939:210). Neither sex nor cranial characters of the original Simia apella are placed in evidence. Obviously, Tate confused his own term crested , referring to cranial characters, with his and my term, “tufted,” referring to …

The Ectotympanic Bone and Origin of Higher Primates

The body of the tympanic annulus in all adults of higher primates (Platyrrhini, Catarrhini) is fused to the external surface of the tympanic bulla while the crural ends are adhered to the squamosal bo

Races of the emperor tamarin,Saguinus imperatorGoeldi (Callitrichidae, Primates)

The two described subspecies of the emperor tamarin,Saguinus imperator imperatorGoeldi andSaguinus imperator subgrisescensLönnberg are defined and compared, the geographic range of each plotted.