Marc Godinot

Early North African Primates and Their Significance for the Origin of Simiiformes (= Anthropoidea)

Twelve years ago, just after the publication of the volume dedicated to platyrrhine origins (Ciochon and Chiarelli, 1980), Hoffstetter made a remarkable attempt to synthesize information and debates about simiiform (= anthropoid) evolution. What he wrote then holds true today: “We are still far away from a consensus about phylogeny and biogeographical history, that is to say about the evolution, of these animals [primates]” (Hoffstetter, 1982, p. 242, translated). In this paper, Hoffstetter drew attention to the inconveniences of the vernacular term “anthropoid,” ambiguous in many languages. In all these languages, anthropoid means apes, often great apes only, which is quite different from “Anthropoidea.” Furthermore, the Code of Zoological Nomenclature recommends that the suffix -oidea be reserved for super-families, an almost universal use in mammalogy. Hoffstetter added: “As Szalay and Delson (1979) revealed the existence of a genus Anthropus, synonym of Homo, Anthropoidea is a synonym of Hominoidea and must be definitely rejected” (Hoffstetter, 1982, translated). I follow the authors who, since this time, use Simiiformes Hoffstetter, 1974 instead of Anthropoidea Mivart, 1864 (vernacular: simiiform or simian).

A Summary of Adapiform Systematics and Phylogeny

The systematics of all adapiforms is reviewed at the generic and specific levels. A new classification is proposed for the 30 genera of adapiforms, containing three families: Notharctidae, Adapidae and Sivaladapidae; and one subfamily of uncertain affinities, the new Pronycticebinae. A stratophenetic schema summarizing the distribution and phylogenetic relationships of all European adapiforms, Cercamoniinae, Notharctinae and Adapidae, is given. The particular characters of the skull of Pronycticebus gaudryi warrant its isolation in a separate subfamily Pronycticebinae, nocturnal adapiforms which are of special significance for lemuriform ancestry. Agerinia might pertain to the same group. Four genera are proposed as adapids outside the European adapine radiation. Amphipithecinae and several other Asiatic genera of uncertain affinities are discussed.

Un gisement sparnacien exceptionnel à plantes, arthropodes et vertébrés (Éocène basal, MP7): Le Quesnoy (Oise, France)

A new fossil locality is reported from the argiles a lignite du Soisonnais (Early Ypresian, MP7) of the Oise region (France). After the preliminary survey of the flora and the vertebrate and arthropod faunas, we propose a reconstruction of a fluvio-lacustrine palaeoenvironment with a forest, under a warm and wet seasonal climate. This site is outstanding because of the richness, diversity and the state of preservation of the fossils. The present discovery opens a unique window on terrestrial life during the Earliest Eocene.

The Early Radiation of Euprimates and the Initial Diversification of Omomyidae

The source of euprimates (Hoffstetter, 1977) or “true primates”—the tax-onomic assemblage including extant lemurs, lorises, tarsiers, and anthropoids and their unquestioned extinct relatives—remains one of the paramount unresolved questions in primate evolution. Any discussion of the origin and initial radiation of euprimates in general, and Omomyidae in particular, must begin with a broader consideration of the origin, relationships, and composition of the order Primates.

Hands of early primates

Questions surrounding the origin and early evolution of primates continue to be the subject of debate. Though anatomy of the skull and inferred dietary shifts are often the focus, detailed studies of postcrania and inferred locomotor capabilities can also provide crucial data that advance understanding of transitions in early primate evolution. In particular, the hand skeleton includes characteristics thought to reflect foraging, locomotion, and posture. Here we review what is known about the early evolution of primate hands from a comparative perspective that incorporates data from the fossil record. Additionally, we provide new comparative data and documentation of skeletal morphology for Paleogene plesiadapiforms, notharctines, cercamoniines, adapines, and omomyiforms. Finally, we discuss implications of these data for understanding locomotor transitions during the origin and early evolutionary history of primates. Known plesiadapiform species cannot be differentiated from extant primates based on either intrinsic hand proportions or hand-to-body size proportions. Nonetheless, the presence of claws and a different metacarpophalangeal [corrected] joint form in plesiadapiforms indicate different grasping mechanics. Notharctines and cercamoniines have intrinsic hand proportions with extremely elongated proximal phalanges and digit rays relative to metacarpals, resembling tarsiers and galagos. But their hand-to-body size proportions are typical of many extant primates (unlike those of tarsiers, and possibly Teilhardina, which have extremely large hands). Non-adapine adapiforms and omomyids exhibit additional carpal features suggesting more limited dorsiflexion, greater ulnar deviation, and a more habitually divergent pollex than observed plesiadapiforms. Together, features differentiating adapiforms and omomyiforms from plesiadapiforms indicate increased reliance on vertical prehensile-clinging and grasp-leaping, possibly in combination with predatory behaviors in ancestral euprimates.

Biomechanical considerations to explain important morphological characters of primate hands

Two morphologically distinct types of primate hands, the «ectaxonic» hand of most strepsirhines, and the «mesaxonic» of many, epecially ground-dwelling, monkeys and of apes and humans, are subject to a biomechanical analysis. A functional explanation for the existence of these two combinations of skeletal and myological characteristics is presented.

Carpal anatomy of Smilodectes gracilis (Adapiformes, Notharctinae) and its significance for lemuriform phylogeny

Abstract The oldest primate carpals collected to date are those of the middle Eocene notharctine Smilodectes gracilis . In general, carpal structure in Smilodectes appears to have been quite generalized compared to that of other living and fossil primates for which wrist anatomy is adequately known. This is reflected by the fact that Smilodectes exhibits several features of wrist anatomy that today are confined either to lemuriforms and Tarsius (“prosimians”) or to haplorhines; in all cases the distribution of these traits among living and fossil primates and eutherians suggests that the character states present in Smilodectes are primitive for primates. Functionally, the wrist of Smilodectes appears to have been relatively less mobile than that of late Eocene Adapis , particularly in movements of pronation/supination at the midcarpal joint and abduction/adduction at the antebrachiocarpal and midcarpal joints. Smilodectes, Notharctus , and Adapis all lack the clearly derived midcarpal anatomy found in extant lemuriforms, strongly suggesting that lemuriforms are monophyletic with respect to these adapiform taxa. The ulnocarpal joint of Smilodectes is similar to that of extant haplorhines and other eutherians, while that of Adapis exhibits the presumably derived morphology that is otherwise restricted to extant lemuriforms. Together with dental anatomy and paleobiogeographic considerations, the ulnocarpal joint of Adapis suggests that this late Eocene adapiform shares more recent common ancestry with lemuriforms than either of these taxa does with Smilodectes .

Early euprimate hands in evolutionary perspective

Abstract Several aspects of Eocene adapiform hands were studied. Terminal phalanges of Smilodectes and Adapis have a distal broadening and a proximal body similar to claw-bearing phalanges. The relative lengths of metacarpals one to three show little specialization in the Messel adapiform and Pronycticebus, reduction of the second metacarpal in Notharctus and Smilodectes, and the proportions of arboreal quadrupeds in Adapis. A group of long-digited fossils, including Notharctus, the Messel adapiform and Europolemur, probably approximates early euprimate hand proportions. Pronycticebus had longer metacarpals more similar to indriids, while Adapis has the shorter digits of an arboreal quadruped. These adapiforms had a divergent thumb, although the degree of divergence can be estimated only in Adapis (35–40° between the first and the second metacarpals). Primitive euprimates probably had distal phalanges with a claw-bearing like body, but with some distal broadening. The simiiform hand is probably not derived from a prosimian grasping hand, a view which seems to be corroborated by the mode of locomotion in Adapis and is in agreement with Napiers analyses.

Lemuriform origins as viewed from the fossil record.

Fossils relevant to lemuriform origins are reviewed. Omanodon seems very close to the other early tooth-combed lemuriforms Karanisia,Wadilemur and Saharagalago, whereas Bugtilemur is rejected from the Lemuriformes. The Djebelemurinae, including Djebelemur and ‘Anchomomys’ milleri, are considered as stem lemuriforms preceding tooth comb differentiation; they are shown to be very distinct from European adapiforms. With tooth-combed lemuriforms present in Africa around 40 million years ago, and stem lemuriforms without tooth combs present on the same continent around 50–48 million years ago, a reasonable scenario can be proposed: tooth comb differentiation and lemuriform dispersal to Madagascar between 52–40 million years ago. The possible significance of Plesiopithecus for daubentoniid origins is raised. A critique of molecular dates is presented in the light of the fossil record. Azibiids are possibly early African prosimians. The timing of the dispersal of primates to Africa and the problem of strepsirhine origins are briefly examined.

Primate Origins: A Reappraisal of Historical Data Favoring Tupaiid Affinities

The origin of primates remains a fascinating question. In spite of many anatomical and molecular studies, the identification of the living sister group of primates is not clearly settled. The lack of consensus about primate origins is the result of the great antiquity of the events that marked primate differentiation. Morphological as well as molecular signals are masked by the amount of subsequent evolution in primates and in potential sister groups, and by the extinction of some critical intermediates. In addition, the Paleocene fossil record of mammals is still particularly poor in Africa and in the southern tropical regions of Asia, where some of the important steps presumably took place. What makes the problem especially puzzling is the realization that the increase in and the enhanced quality of the anatomical and molecular data sets extracted from the living forms did not result in any increased consensus. On the contrary, the cladistic treatment of a large morphological data set concerning archontan phylogeny, assembled by Simmons (1993) from previous