Distal humerus and ulna of Parapresbytis (Colobinae) from the Pliocene of Russia and Mongolia: phylogenetic and ecological implications based on elbow morphology

Abstract

Parapresbytis eohanuman is a colobine known from two middle Pliocene localities southeast of Lake Baikal, northern East Asia. This study examined the morphology of postcranial specimens, a distal humerus and an ulna, of Parapresbytis. A total of 18 and 13 linear measurements were taken from the humerus and the ulna, respectively, and compared with those of extant and European fossil colobines using principal components analysis. The distal humeral specimen of Parapresbytis is slightly larger than those of male Semnopithecus and Nasalis, while the ulnar specimen is much larger than those of extant colobines and is nearly as large as that of a male Papio ursinus. Morphologically, the distal humeri and ulnae of terrestrial colobines such as Semnopithecus, Dolichopithecus, and Mesopithecus can be distinguished from those of arboreal colobines. The morphology of the Parapresbytis elbow is within the range of the arboreal colobines, contradicting previous suggestions that this genus is terrestrially adapted and is phylogenetically close to Dolichopithecus. Because the arboreally adapted elbow is shared by most extant colobines, the morphology of the elbow does not provide evidence for phylogenetic proximity between Parapresbytis and a particular taxon of arboreal colobine such as Rhinopithecus. The elbow morphology suggests that Parapresbytis was adapted to arboreal locomotion as much as the extant arboreal colobines are. This is congruent with the paleoenvironmental evidence, which indicates the presence of forests in the Lake Baikal area during the middle Pliocene.

Locomotor evolution of Mesopithecus (Primates: Colobinae) from Greece: evidence from selected astragalar characters

“…This was also the case with other crown colobines (e.g. Dolichopithecus), which appear to be adapted to a variable regime of terrestriality (Jablonski 2002;Delson et al 2005;Egi et al 2007, Ingicco 2008. The earliest representative of the lineage, the Early Turolian M. delsoni is described as a robustly built monkey similar to extant semiterrestrial colobines (Koufos et al 2003), exploiting relatively open and dry habitats (de Bonis et al 1992(de Bonis et al , 1999Koufos et al 2003).…”

Macaca ulna from new excavations at the Notarchirico Acheulean site (Middle Pleistocene, Venosa, southern Italy)

“…Compared to Dolichopithecus ruscinensis from Montpellier (=Perpignan) and Pestzentlorinc (Delson, 1973), the studied ulna differs in the anteriorly-protruding coronoid process in lateral and medial views, the anterior border of the olecranon higher than the posterior one in lateral and medial views and a larger radial notch in lateral view. The ulnae of the extant colobines differ from that of Notarchirico since those possess an anterior concavity of the proximal shaft and a retroflected olecranon in lateral and medial views (Rose 1998;Egi et al, 2007). The ulnar morphology of M. sylvanus is strongly interrelated with that of the distal epiphysis of the humerus (with which forms the "humeroulnar joint"), and it is linked to its quadrupedal locomotion strategy, with the closepacking position of the elbow providing high stability during parasagittal movements (Rose, 1988).…”

First discovery of colobine fossils from the Late Miocene/Early Pliocene in central Myanmar

“…Parapresbyits is a relatively large, terrestrial colobine, discovered at two Middle Pliocene localities of the Transbaikal area and northern Mongolia (Borissoglebskaya, 1981;Kalmykov and Maschenko, 1992;Maschenko, 2005;Egi et al, 2007;Takai and Maschenko, 2009). In Parapresbytis, the mesiobuccal notch is often well developed, and the M 3 hypoconulid is very large, protruding buccodistally in the type specimen (PIN 3381-235) as seen in Myanmarcolobus, whereas the median lingual notch forms a relatively asymmetrical V shape rather than a trapezoid shape, the M 2 transverse ridges run rather perpendicularly to the tooth row, and the median buccal notch is deeply grooved rather than having the concave pattern seen in Myanmarcolobus.…”

“…Some authorities consider that Dolichopithecus evolved from Mesopithecus by the end of the Miocene (Delson, 1994). Two largesized colobines, Parapresbytis and Kanagawapithecus, discovered from the Middle to Late Pliocene of East Asia (Transbaikalia and Japan, respectively) were once considered to be the subgenera of Dolichopithecus (Borissoglebskaya, 1981;Kalmykov and Maschenko, 1992;Delson, 1994;Iwamoto et al, 2005), but both are now regarded as independent genera, respectively (Jablonski, 2002;Maschenko, 2005;Egi et al, 2007;Takai and Maschenko, 2009;Nishimura et al, 2012). There is another enigmatic colobine tooth from the Early Pliocene that has been discovered in Yushe, Shaangxi Province, northern China, but no detailed descriptions have been published (Delson, 1996;Williams and Holmes, 2011).…”