New primate fossils from late Oligocene (Colhuehuapian) localities of Chubut Province, Argentina

New primate fossils have been recovered from the late Oligocene (Colhuehuapian) localities of Gaiman and Sacanana in Patagonian Argentina. The new fossils are provisionally allocated to Dolichocebus gaimanensis and Tremacebus harringtoni, the only primates previously described from these localities. These new dental remains are more primitive than the teeth of any previously known platyrrhines, living or fossil, and conform extremely well with the hypothetical ancestral morphotype for New World monkeys suggested by several authors. They are also very similar to the teeth of Oligocene catarrhines from Egypt such as Aegyptopithecus zeuxis.     

Anatomy of the bony pelvis in parapithecid primates

Four partial innominate bones, attributed to the parapithecid primates Parapithecus grangeri and Apidium phiomense, have recently been recovered from Oligocene deposits in the Fayum of Egypt. These fossils provide the first documentation of pelvic morphology for early anthropoids. In pelvic anatomy, parapithecids show definite similarities to higher primates rather than to prosimians, but cannot be clearly allied with any one extant group. Functionally, the fossils indicate quadrupedal or leaping habits rather than suspensory or bipedal behaviors.     

The anatomy of Dolichocebus gaimanensis, a stem platyrrhine monkey from Argentina

Dolichocebus is known from the type skull encased in a concretion, numerous isolated teeth, parts of two mandibles, and a talus. The specimens come from the Trelew Member (early Miocene, Colhuehuapian South American Land Mammal Age) of the Sarmiento Formation near the village of Gaiman, Chubut Province, Argentina, dated to about 20Ma. We describe all Dolichocebus fossil material using conventional surface anatomy and micro-CT data from the cranium. The new material and newly imaged internal anatomy of the skull demonstrate that anatomical characters hitherto supposed to support a phyletic link between Dolichocebus and either callitrichines (marmosets, tamarins, and Callimico) or Saimiri (squirrel monkeys) are either indeterminate or absent. To more fully explore the phyletic position of Dolichocebus, we undertook a comprehensive phylogenetic analysis. We examined 268 characters of the cranium and dentition of 16 living platyrrhine genera, some late Oligocene and early Miocene platyrrhines, Tarsius, some Eocene and Oligocene stem anthropoids, and several extant catarrhines. These analyses consistently indicate that Dolichocebus is a stem platyrrhine, as are late Oligocene Branisella and early Miocene Tremacebus, Soriacebus, and Carlocebus. Platyrrhine evolution often is conceived of as a single ancient adaptive radiation. Review of all available phyolgenetic data suggests a more layered evolutionary pattern, with several independent extinct clades filling modern platyrrhine niche space, and modern platyrrhine families and subfamilies appearing over a nine-million-year interval in the Miocene. The outcome of these analyses highlights the pervasiveness of homoplasy in dental and cranial characters. Homoplasy is a real evolutionary phenomenon that is present at all levels of biological analysis, from amino-acid sequences to aspects of adult bony morphology, behavior, and adaptation.     

Similarities in Aegyptopithecus and Afropithecus facial morphology

Recently discovered cranial fossils from the Oligocene deposits of the Fayum depression in Egypt provide many details of the facial morphology of Aegyptopithecus zeuxis. Similar features are found in the Miocene hominoid Afropithecus turkanensis. Their presence is the first good evidence of a strong phenetic link between the Oligocene and Miocene hominoids of Africa. A comparison of trait lists emphasizes the similarities of the two fossil species, and leads us to conclude that the two fossil genera share many primitive facial features. In addition, we studied facial morphology using finite-element scaling analysis and found that the two genera show similarities in morphological integration, or the way in which biological landmarks relate to one another in three dimensions to define the form of the organism. Size differences between the two genera are much greater than the relatively minor shape differences. Analysis of variability in landmark location among the four Aegyptopithecus specimens indicates that variability within the sample is not different from that found within two samples of modern macaques. We propose that the shape differences found among the four Aegyptopithecus specimens simply reflect individual variation in facial characteristics, and that the similarities in facial morphology between Aegyptopithecus and Afropithecus probably represent a complex of primitive facial features retained over millions of years.     

Diet of the Oligocene anthropoidsAegyptopithecus andApidium

Diets of the Oligocene anthropoidsAegyptopithecus zeuxis andApidium phiomense are inferred from measurements of the anterior and posterior dentition of these species. Ideas are presented which can be checked as the hypodigms expand. Comparisons with extant anthropoids demonstrate a probably frugivorous diet forA. zeuxis, while the diet ofA. phiomense was not characterized by a high degree of frugivory requiring extensive incisal preparation of food. Additional inferences about the diet ofA. phiomense might be gleaned from future examination of incisor morphology, implantation and occlusion. Even when allowance is made for the presence of P2 inA. phiomense, the dietary position of this species with respect to extant anthropoids is equivocal, and it is possible that the normal anthropoid relationship between anterior and posterior dentitions, with a small incisor span correlating with a great amount of mastication, had yet to be developed. This report is based in part on an invited paper “Function in primate masticatory musculature as demonstrated by muscle weights” delivered at the symposium “The Behavioral and Morphological Adaptations to Diet Among Primates,” 46th Annual Meeting, American Association of Physical Anthropologists, Seattle, Washington, April 13–16, 1977.     

Astragalar morphology of late Eocene anthropoids from the Fayum Depression (Egypt) and the origin of catarrhine primates

The phylogenetic relationships of the late Eocene anthropoids Catopithecus browni and Proteopithecus sylviae are currently a matter of debate, with opinion divided as to whether these taxa are stem or crown anthropoids. The phylogenetic position of Catopithecus is of particular interest, for, unlike the highly generalized genus Proteopithecus, this taxon shares apomorphic dental and postcranial features with more derived undoubted catarrhines that appear in the same region 1-2 Ma later. If these apomorphies are homologous and Catopithecus is a stem catarrhine, the unique combination of plesiomorphic and apomorphic features preserved in this anthropoid would have important implications for our understanding of the crown anthropoid morphotype and the pattern of morphological character transformations that occurred during the early phases of stem catarrhine evolution.Well-preserved astragali referrable to Proteopithecus, Catopithecus, and the undoubted early Oligocene stem catarrhine Aegyptopithecus have provided additional morphological evidence that allows us to further evaluate competing hypotheses of interrelationships among Eocene-Oligocene Afro-Arabian anthropoids. Qualitative observations and multivariate morphometric analyses reveal that the astragalar morphology of Proteopithecus is very similar to that of early Oligocene parapithecids and living and extinct small-bodied platyrrhines, and strengthens the hypothesis that the morphological pattern shared by these taxa is primitive within crown Anthropoidea. In contrast, Catopithecus departs markedly from the predicted crown anthropoid astragalar morphotype and shares a number of apomorphic features (e.g., deep cotylar fossa, laterally projecting fibular facet, trochlear asymmetry, mediolaterally wide astragalar head) with Aegyptopithecus and Miocene-Recent catarrhines. The evidence from the astragalus complements other independent data from the dentition, humerus and femur of Catopithecus that support this taxon's stem catarrhine status, and we continue to maintain that oligopithecines are stem catarrhines that constitute the sister group of a clade containing propliopithecines and Miocene-Recent catarrhines.     

The ecology of oligocene African anthropoidea

African anthropoids are first recorded in Early Oligocene deposits of the Fayum Province, Egypt. Six genera and nine species are recognized. Estimated body weights for these taxa are based on the regression equation log ₁₀(B) = 2.86log ₁₀(L) + 1.37, whereB is the bodyweight in grams, and Lis the M ₂ length in millimeters. The equation is derived from 106 species of living primates. Fayum species range in body weight from about 600 g (Apidium moustafai)to about 6000 g (Aegyptopithecus zeuxis).A similar range of body weight is found among extant Cebidae. The Fayum primates are larger than any extant insectivorous primates;this fact probably rules out a predominantly insectivorous diet. Extant frugivorous hominoids can be separated from folivorous hominoids on the basis of molar morphology. Folivorous apes (gorilla and siamang) have proportionately more shearing on their molars than do frugivorous species. Based on the hominoid analogy, the molar morphology of the Fayum species is consistent with a frugivorous diet. Parapithecus grangeristands apart from other Fayum species in having better developed molar shearing, possibly indicating that it had more fiber in its diet. Terrestrial species of Old World monkeys tend to have significantly higher molar crowns than do more arboreal species. This difference may relate to an increased amount of grit in the diet of the more terrestrial species, selecting for greater resistance to wear. Oligocene primates have molar crown heights consistent with a primarily arboreal mode of existence. However, the particularly high molar crowns of Parapithecus grangerisuggest that this species may have foraged on the ground to a considerable degree. Other evidence is advanced suggesting that Apidiummay have had a diurnal activity pattern.     

A new species of Propliopithecus from the Fayum, Egypt

Propliopithecus ankeli is described as a new species of hominoid from the early Oligocene of Egypt. The new species occurs at a stratigraphic level 80 m below quarries yielding P. chirobates and Aegyptopithecus zeuxis. P. ankeli differs from other species of the genus in its large size, relatively robust canines, larger and proportionally broader premolars, and M1 that has as great or greater mesiodistal length than M2. Thus, P. ankeli is characterized by increased relative size and robustness of the antemolar dentition, which contrasts with the pattern observed in the Fayum's other large hominoid, A. zeuxis. P. ankeli probably represents a lineage not ancestral to other Fayum hominoids. Discovery of this new species emphasizes the diversity of anthropoid primates that had already evolved by the early Oligocene.     

The humerus of Aegyptopithecus zeuxis: a primitive anthropoid

Two complete humeri of Aegyptopithecus zeuxis have been recovered from Oligocene deposits in the Fayum Province of Egypt. These new specimens support previous interpretations of the locomotor adaptations of this species and indicate that A. zeuxis was a robust, slowly moving arboreal quadruped. While the previously described distal articular region of the humerus is virtually identical with the same region in many extant ceboids and the Miocene hominoid Pliopithecus vindobonensis, the more proximal parts of the humerus show many primitive "prosimianlike" features not found the limbs of extant anthropoids. The primitive features include the absence of a distinct deltoid plane, a broad shallow bicipital groove, a large brachialis flange, and an entepicondylar foramen. In most features, the humerus of Aegyptopithecus zeuxis is more primitive than the hypothetical last common ancestor of extant cercopithecoids and hominoids based on neontological comparisons. This supports other lines of evidence indicating that the hominoids from the Egyptian Oligocene are morphologically ancestral to both Old World monkeys and apes.     

Cranial morphology of Aegyptopithecus and Tarsius and the question of the tarsier-anthropoidean clade

New crania of the Oligocene anthropoidean Aegyptopithecus provide a test of the hypothesized tarsier-anthropoidean clade. Three cranial characters shared by Tarsius and some modern anthropoideans (apical interorbital septum, postorbital septum, "perbullar" carotid pathway) were examined. 1) An apical interorbital septum is absent in Aegyptopithecus. A septum does occur in Galago senegalensis (Lorisidae) and Microcebus murinus (Cheirogaleidae), so the presence of a septum is not strong evidence favoring a tarsiiform-anthropoidean clade. 2) In Aegyptopithecus and other anthropoideans, the postorbital septum is formed mainly by a periorbital flange of the zygomatic that extends medially from the lateral orbital margin onto or near the braincase. The postorbital plate of Tarsius is formed by frontal and alisphenoid flanges that extend laterally from the braincase to the zygomatic's frontal process, which is not broader than the postorbital bars of other prosimians. Periorbital flanges evolved in Tarsius for support or protection of the enormous eyes, as suggested by the occurrence of maxillary and frontal flanges that cup portions of the eye but do not separate it from temporal muscles. 3) The internal carotid artery of Aegyptopithecus enters the bulla posteriorly and crosses the anteroventral part of the promontorium. The tympanic cavity was probably separated from the anteromedial cavity by a septum stretching from the carotid channel to the ventrolateral bullar wall. In Tarsius, the carotid pathway is prepromontorial, and a septum stretches from the carotid channel to the posteromedial bullar wall. Quantitative analyses indicate that anterior carotid position has evolved because of erect head posture. The cranium of Oligocene anthropoideans thus provides no support for the hypothesized tarsier-anthropoidean clade.     

Foot bones from Omo: implications for hominid evolution

We reanalyze a hominid talus and calcaneus from Omo dating to 2.2 mya and 2.36 mya, respectively. Although both specimens occur at different localities and times, both tarsals articulate well together, suggesting a single taxon on the basis of size and function. We attribute these foot bones to early Homo on the basis of their morphology. The more modern-like tarsal morphology of these Omo foot bones makes them very similar to a talus from Koobi Fora (KNM-ER 813), a specimen attributed to Homo rudolfensis or Homo erectus. Although the Omo tarsals are a million years younger than the oldest known foot bones from Hadar, both localities demonstrate anatomical differences representing two distinct morphological patterns. Although all known hominid tarsals demonstrate clear bipedal features, the tarsal features noted below suggest that biomechanical changes did occur over time, and that certain features are associated with different hominid lineages (especially the robust australopithecines).     

Femoral anatomy of Aegyptopithecus zeuxis,an early Oligocene anthropoid

Three partial femora from Quarries I and M of the early Oligocene Jebel Qatrani Formation in the Fayum of Egypt are attributed to Aegyptopithecus zeuxis on the basis of their appropriate size and anthropoid morphology. Compared with extant catarrhines, Aegyptopithecus is unusual in having a distinct gluteal tuberosity (third trochanter) and a relatively deep distal femoral articulation. In the estimated neck angle, Aegyptopithecus resembles arboreal quadrupeds rather than either leaping or suspensory primates. It seems likely that the femur of this species was relatively robust and short for its body mass. In aspects of its femoral anatomy, Aegyptopithecus is quite different from the parapithecid Apidium and more similar to Catopithecus from late Eocene deposits of the Fayum, and also to small hominoids from the Miocene of East Africa. Am J Phys Anthropol 106:413–424, 1998. © 1998 Wiley-Liss, Inc.     

The stuttgart collection of oligocene primates from the fayum province of Egypt

In 1907, R. Markgraf made a small collection of Oligocene fossil primates from Egypt for the Staatliches Museum für Naturkunde in Stuttgart. Circumstances of discovery suggest that this collection came from the same stratigraphic horizon (the Upper Fossil Wood zone) and possibly the same locality as a similar collection made earlier that year byMarkgraf for the American Museum of Natural History in New York. Three new genera and species were described bySchlosser, based on the Stuttgart collection.Parapithecus fraasi Schlosser is a junior synonym ofApidium phiomense Osborn. “Parapithecus“grangeri Simons is placed in the new genusSimonsius. Propliopithecus haeckeli Schlosser andMoeripithecus markgrafi Schlosser have previously been recognized as synonyms. In addition,Aegyptopithecus zeuxis Simons is known from the Upper Fossil Wood zone.     

Traces of the bone-eating annelid Osedax in Oligocene whale teeth and fish bones

The range of substrates that the bone-eating marine worm Osedax is able to consume has important implications for its evolutionary history, especially its potential link to the rise of whales. Once considered a whale specialist, recent work indicates that Osedax consumes a wide range of vertebrate remains, including whale soft tissue and the bones of mammals, birds and fishes. Traces resembling those produced by living Osedax have now been recognized for the first time in Oligocene whale teeth and fish bones from deep-water strata of the Makah, Pysht and Lincoln Creek formations in western Washington State, USA. The specimens were acid etched from concretions, and details of the borehole morphology were investigated using micro-computed tomography. Together with previously published Osedax traces from this area, our results show that by Oligocene time Osedax was able to colonize the same range of vertebrate remains that it consumes today and had a similar diversity of root morphologies. This supports the view that a generalist ability to exploit vertebrate bones may be an ancestral trait of Osedax.     

山东地区清墓中女性居民的缠足现象

山东安丘牟山水库遗址和广饶十村遗址的清代墓葬中出土了存在足部畸形的3例女性个体,结合历史记载以及近代缠足女性X光照片的对比,推测应为缠足后所产生的现象。通过观察其足部骨骼,总结出缠足畸形在骨骼标本上的几个特点:1)足部骨骼整体纤弱化,以跖骨最为明显;2)跖骨的跖跗关节处以及跗骨出现楔形改变;3)下肢骨肌嵴不发达,骨骼表面较为光滑,胫骨下端前缘出现关节面。缠足组与未缠足组进行对比发现,跖骨是差异最为明显的骨骼,且缠足组的肢骨粗壮度稍弱于未缠足组。     

Non-metric features in the ulna of Aegyptopithecus, Alouatta, Ateles, and Lagothrix.

A comparison of the non-metric features of the ulnar fragment (YPM 23940) referred to Aegyptopithecus zeuxis with those in the same bone of Alouatta, Ateles, and Lagothrix -- the three living taxa whose ulnae most closely resemble that of the fossil -- reveals that the closest similarities of the fragment are with the ulna of Alouatta.     

Osteological evidence for the evolution of activity pattern and visual acuity in primates

Examination of orbit size and optic foramen size in living primates reveals two adaptive phenomena. First, as noted by many authors, orbit size is strongly correlated with activity pattern. Comparisons of large samples of extant primates consistently reveal that nocturnal species exhibit proportionately larger orbits than diurnal species. Furthermore, nocturnal haplorhines (Tarsius and Aotus) have considerably larger orbits than similar-sized nocturnal strepsirrhines. Orbital hypertrophy in Tarsius and Aotus accommodates the enormously enlarged eyes of these taxa. This extreme ocular hypertrophy seen in extant nocturnal haplorhines is an adaptation for both enhanced visual acuity and sensitivity in conditions of low light intensity. Second, the relative size of the optic foramen is highly correlated with the degree of retinal summation and inferred visual acuity. Diurnal haplorhines exhibit proportionately larger optic foramina, less central retinal summation, and much higher visual acuity than do all other primates. Diurnal strepsirrhines exhibit a more subtle but significant parallel enlargement of the optic foramen and a decrease in retinal summation relative to the condition seen in nocturnal primates. These twin osteological variables of orbit size and optic foramen size may be used to draw inferences regarding the activity pattern, retinal anatomy, and visual acuity of fossil primates. Our measurements demonstrate that the omomyiforms Microchoerus, Necrolemur, Shoshonius, and Tetonius, adapiform Pronycticebus, and the possible lorisiform Plesiopithecus were likely nocturnal on the basis of orbit diameter. The adapiforms Leptadapis, Adapis, and Notharctus, the phylogenetically enigmatic Rooneyia, the early anthropoids Proteopithecus, Catopithecus, and Aegyptopithecus, and early platyrrhine Dolichocebus were likely diurnal. The activity pattern of the platyrrhine Tremacebus is obscure. Plesiopithecus, Pronycticebus, Microchoerus, and Necrolemur probably had eyes that were very similar to those of extant nocturnal primates, with a high degree of retinal summation and rod-dominated retinae. Leptadapis and Rooneyia likely had eyes similar to those of extant diurnal strepsirrhines, with moderate degrees of retinal summation, a larger cone:rod ratio than in nocturnal primates, and, more speculatively, well-developed areae centrales similar to those of diurnal strepsirrhines. Adapis exhibited uncharacteristically high degrees of retinal summation for a small-eyed (likely diurnal) primate. None of the adapiform or omomyiform taxa for which we were able to obtain optic foramen dimensions exhibited the extremely high visual acuity characteristic of extant diurnal haplorhines.     

Tarsals of the extinct insectivoran family Nyctitheriidae (Mammalia): evidence for archontan relationships

Astragali and calcanea from the English late Eocene, attributed to the extinct 'insectivoran' family Nyctitheriidae, are described for the first time. They contrast with those of the strict sense insectivorans, the Lipotyphla, in which order nyctitheres have usually been placed, and compare more closely with those of Scandentia (tree shrews) and the extinct Plesiadapiformes. Functional analysis demonstrates that inversion of the foot was possible between the astragalus and calcaneum of nyctitheres, allowing them to be interpreted as having had a tree-dwelling, probably scansorial, mode of life. These tarsal bones are compared with those of other placental mammals. Cladistic analysis of tarsal characters places nyctitheres as sister group to the Plesiadapiformes within the superorder Archonta, excluding Chiroptera (bats). An independent analysis of dental characters places them as sister group to the rest of the Archonta, but still excluding bats. Combining the dental and tarsal characters places nyctitheres as sister group to Plesiadapiformes and all modern groups of archontans except bats. A new osteological synapomorphy is proposed for the Archonta, which is thus considered to comprise Chiroptera, Deccanolestes , Nyctitheriidae, Plesiadapiformes, Dermoptera (including Mixodectidae), Scandentia and Primates. Insectivorans s.l . have long been at the centre of arguments on placental origins, although lipotyphlans are usually regarded as a monophyletic group, rather than paraphyletic stem placentals. Reidentification of an extinct lipotyphlan family as having archontan relationships raises the possibility of advances in other areas of insectivoran phylogeny when more postcranial elements become known. The early Oligocene extinction of nyctitheres may be causally related to the rise of insectivorous microchiropteran bats, which, because of their flying ability, would have been able to forage more widely.     

Determination of adult stature from metatarsal length

The results of a study to determine the value of foot bones in reconstructing stature are presented. The data consist of length measurements taken on all ten metatarsals as well as on cadaver length from a sample of 130 adults of documented race, sex, stature, and, in most cases, age. Significant correlation coefficients (.58-.89) are shown between known stature and foot bone lengths. Simple and multiple regression equations computed from the length of each of these bones result in standard errors of estimated stature ranging from 40-76 mm. These errors are larger than those for stature calculated from complete long bones, but are approximately the same magnitude for stature calculated from metacarpals and fragmentary long bones. Given that metatarsals are more likely to be preserved unbroken than are long bones and given the ease with which they are accurately measured, the formulae presented here should prove useful in the study of historic and even prehistoric populations.