Extinct Monkey Research Articles

Dietary niches of terrestrial cercopithecines from the Plio-Pleistocene Shungura Formation, Ethiopia: evidence from Dental Microwear Texture Analysis

This study aims to explore the feeding ecology of two terrestrial papionins, Papio and Theropithecus from the Shungura Formation in Ethiopia, the most complete stratigraphic and paleontological record of the African Plio-Pleistocene. Two aspects were evaluated using Dental Microwear Texture Analysis: differences in diet between the extinct genera and their extant relatives, and any potential dietary fluctuations over time. Amongst more than 2,500 cercopithecid dental remains, 154 Theropithecus molars and 60 Papio molars were considered. Thirty-nine extant wild baboons and 20 wild geladas were also considered. The results show that diets of extinct monkeys from Member G already differed between genera as it is the case for their extant representatives. The shearing facets on the Theropithecus molars display significant variations in microwear textures, suggesting several dietary shifts over time. Two events point to higher intakes of herbaceous monocots (tougher than dicots foliages), at about 2.91 Ma (between members B and C) and at 2.32 Ma (between members E and F). These two events are separated by an inverse trend at about 2.53 Ma (between members C and D). Some of these variations, such as between members E and F are supported by the enamel carbon isotopic composition of herbivorous mammals and with paleovegetation evidence.

A (New World Monkey) Tree Grows in Brooklyn

A (New World Monkey) Tree Grows in Brooklyn

An extinct monkey from Haiti and the origins of the Greater Antillean primates

A new extinct Late Quaternary platyrrhine from Haiti, Insulacebus toussaintiana, is described here from the most complete Caribbean subfossil primate dentition yet recorded, demonstrating the likely coexistence of two primate species on Hispaniola. Like other Caribbean platyrrhines, I. toussaintiana exhibits primitive features resembling early Middle Miocene Patagonian fossils, reflecting an early derivation before the Amazonian community of modern New World anthropoids was configured. This, in combination with the young age of the fossils, provides a unique opportunity to examine a different parallel radiation of platyrrhines that survived into modern times, but is only distantly related to extant mainland forms. Their ecological novelty is indicated by their unique dental proportions, and by their relatively large estimated body weights, possibly an island effect, which places the group in a size class not exploited by mainland South American monkeys. Several features tie the new species to the extinct Jamaican monkey Xenothrix mcgregori, perhaps providing additional evidence for an inter-Antillean clade.

Preliminary notes on a newly discovered skull of the extinct monkey Antillothrix from Hispaniola and the origin of the Greater Antillean monkeys

Body mass is an important component of any paleobiological reconstruction. Reliable skeletal dimensions for making estimates are desirable but extant primate reference samples with known body masses are rare. We estimated body mass in a sample of extinct platyrrhines and Fayum anthropoids based on four measurements of the articular surfaces of the humerus and femur. Estimates were based on a large extant reference sample of wild-collected individuals with associated body masses, including previously published and new data from extant platyrrhines, cercopithecoids, and hominoids. In general, scaling of joint dimensions is positively allometric relative to expectations of geometric isometry, but negatively allometric relative to expectations of maintaining equivalent joint surface areas. Body mass prediction equations based on articular breadths are reasonably precise, with %SEEs of 17–25%. The breadth of the distal femoral articulation yields the most reliable estimates of body mass because it scales similarly in all major anthropoid taxa. Other joints scale differently in different taxa; therefore, locomotor style and phylogenetic affinity must be considered when calculating body mass estimates from the proximal femur, proximal humerus, and distal humerus. The body mass prediction equations were applied to 36 Old World and New World fossil anthropoid specimens representing 11 taxa, plus two Haitian specimens of uncertain taxonomic affinity. Among the extinct platyrrhines studied, only Cebupithecia is similar to large, extant platyrrhines in having large humeral (especially distal) joints. Our body mass estimates differ from each other and from published estimates based on teeth in ways that reflect known differences in relative sizes of the joints and teeth. We prefer body mass estimators that are biomechanically linked to weight-bearing, and especially those that are relatively insensitive to differences in locomotor style and phylogenetic history. Whenever possible, extant reference samples should be chosen to match target fossils in joint proportionality.

Postcranial Remains of the Extinct Monkeys of the Greater Antilles, with Evidence for Semiterrestriality in Paralouatta1

This paper describes postcranial remains pertaining to the endemic xenotrichin callicebines of the Greater Antilles, all of which are extinct: Xenothrix mcgregori (Jamaica), Antillothrix bernensis (Hispaniola), and Paralouatta varonai and P. marianae (Cuba). These monkeys differed considerably in body size and inferred locomotor behavior. Xenothrix and Antillothrix are estimated to have weighed 2–5 kg, which is well within the middle range of body sizes found in extant South American monkeys, but Paralouatta (~9–10 kg) would have been nearly as large as the largest living platyrrhines. In line with previous studies, we interpret Xenothrix mcgregori as a rather short-limbed, slow-moving arboreal quadruped possessing some unusual features not otherwise seen in platyrrhines (e.g., adductor process or “fourth trochanter” of the femur). Its closest locomotor analog among living primates remains uncertain. Paralouatta varonai also exhibits features not seen in other platyrrhines, but in this case there are intriguing resemblances to certain Old World monkeys (e.g., retroflexed medial epicondyle and narrow trochlea on humerus, stabilization features of talocrural joint, short digital rays), especially so-called semiterrestrial cercopithecines whose locomotor repertoire includes a significant amount of movement on the ground (e.g., Cercopithecus lhoesti). At the same time, the Cuban monkey conspicuously lacks most features uniquely connected with suspensory activities, otherwise seen in all living platyrrhines of large body size. The locomotor and postural repertoire of Antillothrix is unresolved, as the only element currently available for analysis is a distal tibia. The tibia of the Hispaniolan monkey is not very informative from a functional standpoint, although it exhibits less emphasis on talocrural stabilization than does the equivalent element in Paralouatta (e.g., size of medial malleolus). The diverse postcranial specializations exhibited by xenotrichins are consistent with their long isolation (at least since Oligocene) on land masses in the Caribbean Sea.