Fossil Platyrrhines Research Articles

New specimens of the oldest fossil platyrrhine, Branisella boliviana, from Salla, Bolivia.

During the 1992 and 1993 field seasons, several new specimens of Branisella boliviana, the oldest fossil platyrrhine, were discovered in the late Oligocene deposits at Salla, northwestern Bolivia. The new materials are two maxillary fragments and seven mandibular fragments, including P3 and P2, neither of which have previously been recovered. All new and previously reported materials, including the holotype and referred specimens, were apparently recovered from the same horizon, called the Branisella zone (MacFadden et al. [1985] J. Geol. 93:223-250; MacFadden [1990] J. Hum. Evol. 19:7-21. The crown morphology of the newly discovered upper and lower premolars suggests that Branisella has a close affinity with callitrichines. A detailed examination of all molar specimens suggests that "Szalatavus attricuspis," which was recovered at Salla in 1981 and described as a new genus by Rosenberger et al. (1991), is a junior synonym of Branisella. The Branisella-like upper molar, in which a small hypocone is preserved on the poorly developed distolingual cingulum, is a shared-derived character with callitrichines and does not correspond to the primitive state for platyrrhine phylogeny. The ancestral upper molar morphotype for platyrrhines should have a moderate to large hypocone and a well developed talon area.

New specimens of the oldest fossil platyrrhine, Branisella boliviana, from Salla, Bolivia

During the 1992 and 1993 field seasons, several new specimens of Branisella boliviana, the oldest fossil platyrrhine, were discovered in the late Oligocene deposits at Salla, northwestern Bolivia. The new materials are two maxillary fragments and seven mandibular fragments, including P3 and P2, neither of which have previously been recovered. All new and previously reported materials, including the holotype and referred specimens, were apparently recovered from the same horizon, called the Branisella zone (MacFadden et al. [1985] J. Geol. 93:223–250; MacFadden [1990] J. Hum. Evol. 19:7–21. The crown morphology of the newly discovered upper and lower premolars suggests that Branisella has a close affinity with callitrichines. A detailed examination of all molar specimens suggests that “Szalatavus attricuspis,” which was recovered at Salla in 1981 and described as a new genus by Rosenberger et al. (1991), is a junior synonym of Branisella. The Branisella-like upper molar, in which a small hypocone is preserved on the poorly developed distolingual cingulum, is a shared-derived character with callitrichines and does not correspond to the primitive state for platyrrhine phylogeny. The ancestral upper molar morphotype for platyrrhines should have a moderate to large hypocone and a well developed talon area. © 1996 Wiley-Liss, Inc.

Large fossil platyrrhines from the Rı́o Acre local fauna, late Miocene, western Amazonia

Large fossil platyrrhines from the Rı́o Acre local fauna, late Miocene, western Amazonia

New fossil platyrrhine tali from the early miocene of Argentina

AbstractFive platyrrhine tali have been recovered from early Miocene localities in the Pinturas Formation of Santa Cruz Province, Argentina. These new fossil tali show overall greater similarities to the slightly older Gaiman talus attributed to Dolichocebus gaimanensis than to tali of the younger primate taxa from La Venta, Colombia. The smallest and oldest talus from the Pinturas Formation displays features similar to the extant atelines and Pithecia, and is provisionally referred to Soriacebus ameghinorum. The four larger Pinturas tali are provisionally referred to Carlocebus cf. carmenensis, and most resemble tali of the extant small‐bodied cebids and callitrichids. The differences in talar morphology exhibited by these two genera suggest that Soriacebus had a more derived locomotor repertoire than Carlocebus, which included more climbing and possibly suspensory behaviors.

New platyrrhine tali from La Venta, Colombia

Two new primate tali were discovered from the middle Miocene of South America at La Venta, Colombia. IGM-KU 8802 is similar in morphology toCallicebus andAotus, and is allocated to cf.Aotus dindensis, while IGM-KU 8803, associated with a dentition of a new cebine primate, is similar toSaimiri. Both tali differ from the other known fossil platyrrhine tali,Dolichocebus andCebupithecia, and increase our knowledge of the locomotor diversity of the La Venta primate fauna.

New fossil platyrrhines from the Pinturas Formation, southern Argentina

Recent paleontological fieldwork in southern Argentina has generated many new primate fossils from the early-middle Miocene Pinturas Formation in the northwestern part of Santa Cruz Province. This paper describes three new species—a small species of the previously described genus,Soriacebus, and two species of a new, larger genus more similar toHomunculus. A fossil primate from Colhuehuapian deposits at the Gran Barranca in nearby Chubut Province, previously assigned toHomunculus, is provisionally placed in the genusSoriacebus. All of the fossil platyrrhines from Santa Cruz Province have been repeatedly shown to have phenetic similarities toAotus, Callicebus and pitheciines, but their phyletic relations are far from resolved.

Sedimentary paleoenvironments of fossil platyrrhine localities, Miocene Pinturas Formation, Santa Cruz Province, Argentina

Abstract The Pinturas Formation is a pyroclastic and epiclastic aeolian deposit of Miocene age lying discordantly upon Jurassic rocks in the elevated Andean precordillera of northwest Santa Cruz Province, Argentina. The history of development of the Pinturas Formation was significantly affected by the gradual, though sporadic, draping of this aeolian sediment across a profound, slowly filling paleotopography. The Pinturas depositional cycle consisted of: (1) minor aeolian deposition followed by soil formation, and (2) major aeolian deposition followed by intervals of regional erosion. Fluvial action seems to have been almost wholly confined to intraformational erosion, and two significant intraformational erosional unconformities divide the Pinturas Formation into three sequences. The lower sequence is dominated by pyroclastic mudrocks upon which were formed very mature, probably mollic, paleosols; the middle sequence is composed largely of epiclastic sand occurring as barchanoid paleodunes; and the upper sequence consists of massive, poorly bedded pyroclastic mudrocks. Many Pinturas lacunae were reconstructed on the basis of locally preserved strata, and a novel method of holostrome reconstruction using relative paleosol maturities places Pinturas sedimentation in a more accurate temporal light. It also indicates: (1) that the Pinturas sediment accumulation rate increased with time; (2) that regional erosive intervals are correlated directly with major influxes of pyroclastic material; and (3) that the introduction of the Pinturas platyrrhine primates occurred in the sequence: Carlocebus carmenensis, C. intermedius and Soriacebus ameghinorum. Soriacebus adrianae . Pinturas paleosols appear to have formed under moist conditions, and both mature and immature varieties yield a host of ichnofossils. These include the burrows and nests of bees, scarabeid beetles, termites, and at least two different kinds of colonial rodents, in addition to rhizoliths and the calcified boles and root systems of trees. A fossil nest of a nasutitermitine termite in the lower sequence of the formation indicates the presence of tropical forest. Climatic conditions may have been drier during deposition of the barchanoid paleodunes in early late Pinturas time, or the dunes might reflect drier source areas or have simply encroached on areas of highland forest. Fossil mammals are abundant in Pinturas sediments, and attritional concentrations of them were recognized in the upper parts of paleosols and on the floors of erosional scours. Radiometric dates indicate that the fossil mammals (including platyrrhine primates) occurring in the lower and middle parts of the formation may range in age from about 16·6 to younger than 13·3 Ma (million years ago) (Santacrucian and, almost certainly, Friasian land-mammal ages). This age range is somewhat younger than previous estimates, and suggests that the Pinturas faunas correlate broadly with those from the type Santa Cruz Formation, with the presumed position of the type Friasian, and with the base of the marine Gaiman Formation in the lower valley of the Rio Chubut.

Primate adaptation and evolution

Tables & Illustrations. Preface. Adaptation, Evolution, and Systematics. The Primate Body. Primate Lives. Prosimians. New World Anthropoids. Old World Monkeys. Apes and Humans. Primate Communities. Primate Adaptations. The Fossil Record. Primate Origins. Fossil Prosimians. Early Anthropoids. Fossil Platyrrhines. Fossil Apes. Fossil Old World Monkeys. Hominids, the Bipedal Primates. Patterns in Primate Evolution. Index.

Fossil platyrrhine forelimb bones from the early miocene of Argentina.

Primate scapula and ulna fragments of uncertain taxonomic affinity (MACN-SC 101) have been recovered from the Pinturas deposits at Arroyo Feo, Santa Cruz, Argentina in association with Santacrucian (Early Miocene) land mammals. Least-squares regression of body weight on surface area and on height of the glenoid fossa of the scapula indicates an estimated mean weight of 3.6 kg for this individual. On the basis of qualitative and several metric features, the fossil scapula and ulna most closely resemble living platyrrhine monkeys. In estimated body weight and relative height of the coronoid process, the fossil is similar to arboreal quadrupeds, such as Cebus apella and Chiropotes. However, spinoglenoid, axilloglenoid, and axillospinal angles, length of lever arm, and length and breadth of the sigmoid notch imply behavioral similarity with larger species that also use their forelimbs extensively in climbing, such as Alouatta and Lagothrix. MACN-SC 101 may represent the incipient divergence of a generalized platyrrhine arboreal quadruped toward a more suspensory form.

Locomotor behavior and skeletal morphology of two sympatric pitheciine monkeys, Pithecia pithecia and Chiropotes satanas

Field observations of two sympatric pitheciine species reveal that the positional repertoire of the white-faced saki, Pithecia pithecia, is dominated by leaping behaviors, whereas the bearded saki, Chiropotes satanas, is predominantly quadrupedal. Examination and comparison of the postcranial skeletal morphologies and limb proportions of these species display numerous features associated with their respective locomotor behaviors. These observations accord with associations found in other primate and mammalian groups and with predictions based on theoretical and experimental biomechanics. Preliminary observations of the skeletal morphology of Cacajao calvus demonstrate a marked similarity to that of Chiropotes. The fossil platyrrhine Cebupithecia sarmientoi displays greater similarity to Pithecia, suggesting that its positional repertoire also included significant leaping and clinging behaviors.

New Fossil Platyrrhines from Santa Cruz Province, Argentina

New platyrrhine fossils have been recovered from early Miocene deposits near the Pinturas River in Santa Cruz Province, Argentina. Soriacebus ameghinorum is a saki-sized monkey with a deep V-shaped mandible, large procumbent incisors and small marmoset-like cheek teeth. Several other primate taxa are represented by dental, cranial, and post-cranial remains from the same deposits. These fossils document the presence of a phyletically and adaptively diverse fauna of primates in southernmost Argentina during the early Miocene.

New World Primate Field Studies: What's in it for Anthropology?

The living New World or neotropical primates, infraorder Platyrrhini or Superfamily Ceboidea, range from about 24?N. in Tamaulipas, Mexico (spider and howler monkeys) to about 30?S. in Rio Grande do Sul, Brazil (howlers) (167). Fossil platyrrhines have been found near the southern tip of South America in Santa Cruz, Argentina (197), but they are not known to have ranged farther north than they do today. They moved into Central America only after establishment of the Panamanian land bridge in the Late Miocene to Early Pliocene, 5-6 million years ago (235). The platyrrhines are found primarily in forested habitats, including both dry forest and rain forest, up to 3200 m elevation (night monkeys and howler monkeys) (94). Although they do not occur on open savanna as do Old World baboons and patas monkeys, howlers and marmosets and perhaps others do occur in open scrub and sparsely wooded or low canopied dry woodlandllanos (Colombia and Venezuela), cerrado (Brazil), pampas (Argentina), or chaco (Bolivia and Paraguay). All platyrrhines are diurnal except the night monkey Aotus. They range in size from the pygmy marmoset (100-120 g adult body size) to the woolly spider monkey or muriqui which weighs up to 15 kg. There are disagreements at many levels about the taxonomy of the Platyrrhini. This is not the place to discuss these problems, but recognizing the controversies, I have adopted a distillation of two modern classifications, by Rosenberger (201) and by Ford (72), as presented in Table 1. For consistency all discussions in this chapter refer to this classification. A recent alternative

A mandible ofBranisella boliviana (Platyrrhini, Primates) from the oligocene of South America

A mandibular specimen from the Bolivian Early Oligocene is provisionally assigned toBranisella boliviana. The crown anatomy of the single preserved tooth, an M2, indicates platyrrhine affinities and several details of the broken jaw are suggestive of symphyseal fusion. Like the African Oligocene parapithecids,Branisella contrasts with extant anthropoids in the relative shallowness of its mandible.Branisella is the most ancient, and seemingly the most primitive, fossil platyrrhine monkey, lacking any of the derived features of the two major clades of modern ceboids. Taxonomically, it is best regarded as family incertae sedis.

The specializations of man and his place among the catarrhine primates.

From all comparative-anatomical knowledge it has become abundantly proved that man belongs to the suborder of simian primates. This suborder is readily and naturally divided into two distinct, main groups, namely, one of the New World and one of the Old World. The animals of the first group possess without exception three premolar teeth on each side of both jaws, whereas those of the second group have only two of such teeth, and the former lack a bony auditory canal which develops in all the latter during postnatal life. On the basis of these and numerous other, constant anatomical differences between the American, or platyrrhine, and the Old World, or catarrhine, primates man must be assigned to the latter group. No fossil catarrhine has ever been discovered in the Western hemisphere, nor any fossil platyrrhine in the Eastern one, hence it must be assumed that the separation between these...