1 Primate Origins and Supraordinal Relationships: Morphological Evidence

Silcox, Mary; Sargis, Eric J.; Bloch, Jonathan I.; Boyer, Doug M

doi:10.1007/978-3-540-33761-4_29

Cited by 76 publications

(31 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although UALVP 50991 seems more advanced in some respects than Purga− torius (e.g., symmetry of the parastylar and metastylar lobes, rounded anterolabial and posterolabial corners of the crown, labial extension of pre− and postcingulum, robust postproto− conal fold, talon basin), it shows no evidence of the greater bunodonty and capacity for ectental movement and lingual phase grinding that are already evident in Purgatorius (Fig. 2) and that purportedly marked the transition from insectivory to omnivory in primate origins (e.g., Szalay 1968;Szalay and Delson 1979;Silcox et al 2007;Silcox and Gunnell 2008). In the perspective of Hiiemäe and Kay's (1973) precept relating occlusal morphology to jaw movement, Phoxomylus had no capacity for substantial ectental movement of the lower mo− lars on the uppers.…”

Section: Discussionmentioning

confidence: 99%

“…Besides their systematic implications, these fea− tures have paleobiological consequences that are unexpected in the context of early primate evolution as presently under− stood and accordingly are of heightened interest. These con− sequences relate to diet of the Cochrane species and in turn, to dietary factors that are often hypothesized to have driven the transition from the non−primate ancestors of plesiadapi− forms to plesiadapiforms and thereby to primates (e.g., Szalay 1968;Butler 1973;Silcox et al 2007). …”

Section: Discussionmentioning

confidence: 99%

“…2). Puragtorius is generally considered to be the dentally most primitive known primate, living or extinct, i.e., the taxon that is basal to the primate radiation as presently reconstructed from the fossil record (e.g., Silcox et al 2007;Silcox 2008;Silcox and Gunnell 2008). While the upper molars of Purgatorius (e.g., Kielan−Jaworowska et al 1979: fig.…”

Section: Discussionmentioning

confidence: 99%

“…The precingulum is narrow but robust, and although worn, was originally crenulated and ir− regularly pitted along its length; the adjacent parts of the protocone wall are marked by several irregular, low, vertical ridges and shallow grooves. Posteriorly, the postprotoconal fold, an unambiguous primate synapomorphy Silcox et al 2007), arises near the apex of the protocone but apparently not from the apex itself, although the enamel here has been damaged and the precise relationship between the two features is accordingly uncertain. The postprotoconal fold rapidly increases in height, becoming a short but robust crest that in posterior view is nearly vertical on the posterior wall of the protocone.…”

Section: Systematic Paleontologymentioning

confidence: 98%

See 3 more Smart Citations

Edworthia Lerbekmoi, a New Primitive Paromomyid Primate from the Torrejonian (Early Paleocene) of Alberta, Canada

2010

View full text Add to dashboard Cite

A primitive paromomyid plesiadapiform primate, Edworthia lerbekmoi new genus and species, is described from a recently discovered locality in the Paskapoo Formation, exposed at a road cut in Edworthy Municipal Park, Bow River Valley, Calgary, Alberta, Canada. The new taxon, probably middle Torrejonian (To2) in age, is based on two dentary fragments containing well-preserved dentitions that bracket p2-4, m1-3. With the exception of the basal Paromomys, E. lerbekmoi differs from all other paromomyids in retaining p2, but p2 in the new paromomyid is single-rooted, not two-rooted as in Paromomys. E. lerbekmoi differs further from Paromomys in having an enlarged anterior alveolus for a tooth immediately anterior to p2, hypothesized to be il. Unlike other paromomyids with an enlarged il, however, this tooth in E. lerbekmoi was obliquely, not horizontally, oriented and its alveolus opens dorsally, in the alveolar row, not anteriorly, as in other paromomyids in which il is greatly enlarged. This suggests that E. lerbekmoi represents a previously unknown paromomyid lineage that evolved from an ancestor having obliquely oriented lower incisors as in the basal primate Purgatorius, not from an ancestor in which il was already subhorizontal in orientation, as in Paromomys. If this working hypothesis is correct or whether in the future some other evolutionary scenario will better account for the unique anterior dentition in E. lerbekmoi, the new paromomyid nonetheless demonstrates that crucial aspects of the earliest history of the important plesiadapiform family Paromomyidae remain to be discovered.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Systematic Paleontologymentioning

confidence: 98%

See 2 more Smart Citations

Edworthia Lerbekmoi, a New Primitive Paromomyid Primate from the Torrejonian (Early Paleocene) of Alberta, Canada

2010

View full text Add to dashboard Cite

show abstract

“…The differences in the endocast between Rhombomylus and I. graybullianus may be in part a result of the latter's arboreal habitus, although if this is the case it would be expected that these changes might have evolved at the Euarchonta node rather than the Primates node, as the common ancestor of Euarchonta was likely arboreal (46). Unfortunately, until well-preserved cranial fossils of scandentians and dermopterans are discovered, the timing of these changes cannot be assessed.…”

Section: Hypotheses For Brain Size Increase In Primatesmentioning

confidence: 99%

Virtual endocast of Ignacius graybullianus (Paromomyidae, Primates) and brain evolution in early primates

Silcox

Dalmyn

Bloch

2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

133

View full text Add to dashboard Cite

Extant primates are distinctive among mammals in having relatively large brains. As stem primates, Paleogene plesiadapiforms provide direct information relevant to the earliest stages in the evolution of this characteristic. Here we describe a virtual endocast reconstructed from ultra high resolution X-ray computed tomography data for the paromomyid plesiadapiform Ignacius graybullianus (USNM 421608) from the early Eocene of Wyoming. This represents the most complete endocast known for a stem primate, allowing for an unprecedented study of both size and fine details of anatomy. Relative to fossil and extant euprimates, I. graybullianus had large olfactory lobes, but less caudal development of the cerebrum and a poorly demarcated temporal lobe, suggesting more emphasis on olfaction and a less well developed visual system. Although its brain was small compared to those of extant primates, the encephalization quotient of I. graybullianus is higher than that calculated for Paleocene Plesiadapis cookei and overlaps the lower portion of the range documented for fossil euprimates. Comparison to the basal gliroid Rhombomylus suggests that early primates exhibited some expansion of the cerebrum compared to their ancestors. The relatively small brain size of I. graybullianus, an arboreal frugivore, implies that neither arboreality nor frugivory was primarily responsible for the expanded brains of modern primates. However, the contrasts in features related to the visual system between I. graybullianus and fossil and extant euprimates suggest that improvements to these portions of the brain contributed to increases in brain size within Euprimates.computed tomography ͉ Eocene ͉ plesiadapiforms ͉ vertebrate paleontology ͉ Wyoming

show abstract

Primates (Lemurs, Lorises, Tarsiers, Monkeys and Apes)

Rosenberger

Hartwig

2013

Encyclopedia of Life Sciences

View full text Add to dashboard Cite

The modern primates are a diverse order of mammals that includes lemurs, lorises, tarsiers, monkeys, apes and humans. They are united by a 65 My evolutionary history originally built on an adaptive foundation of tropical arboreality and so they share a collection of traits that are unique among mammals, such as an excellent sense of balance, acute vision, good hand–eye coordination, a large grasping first toe, prehensile feet and hands and a flexible, athletic limb anatomy. Primates also tend to live in relatively large social groups and often have correlatively enlarged brains. They almost always give birth to singletons that grow over a prolonged period, which is advantageous to cognitive development, learning and socialisation. Fossil nonhuman primates have been found on all continents but Australia and Antarctica. Primates have been important elements of tropical and subtropical faunas since mammals rebounded following the mass extinction that also promoted the demise of dinosaurs. Key Concepts: Primates are a highly diversified and successful order of mammals adapted to an arboreal, tropical lifestyle. There are three major surviving radiations – lemurs and lorises (strepsirhines) and Old World monkeys and apes (catarrhines) occur in Africa and Asia, and New World monkeys (platyrrhines) live in Central and South America – but many species are now threatened with extinction and the fourth radiation consists of only one genus, the tarsiers of eastern Asia. Although they arose from different ancestral stocks and display their own distinctive character, each radiation exhibits parallel evolution in dietary, locomotory and social adaptation to a treed environment, and all exhibit the universal primate characteristics of grasping big toes, some form of manual prehension and a preference for eating fruits – except for the exclusively predaceous tarsiers. Fossil primates are fairly well known and modern in appearance as early as the Eocene epoch, when many existing orders of mammals are also prevalent, but there is controversy as to where to set the primate–nonprimate boundary that influences how the older plesiadapiforms should be classified – in or outside of the primate order. The two largest primate clades, strepsirhines and haplorhines, one heavily reliant on the sense of smell and basically nocturnal and the other depending on vision and essentially diurnal, already existed approximately 55 Ma, but where and when anthropoids split from early haplorhines, and how the earliest members can be identified from limited sets of fossils, has not been determined. The New World platyrrhine monkeys are an early offshoot of anthropoids and only distantly related to Old World monkeys, a group that is more closely related to apes and humans. Increasing brain size as a correlate of increasing social group size is a pattern that evolved multiple times among anthropoids, irrespective of dietary preferences. The prolific early apes of the Miocene were eclipsed by the diversification of Old World monkeys in forested and open country habitats, especially in sub‐Saharan Africa.

show abstract

1 Primate Origins and Supraordinal Relationships: Morphological Evidence

Cited by 76 publications

References 92 publications

Edworthia Lerbekmoi, a New Primitive Paromomyid Primate from the Torrejonian (Early Paleocene) of Alberta, Canada

Edworthia Lerbekmoi, a New Primitive Paromomyid Primate from the Torrejonian (Early Paleocene) of Alberta, Canada

Virtual endocast of Ignacius graybullianus (Paromomyidae, Primates) and brain evolution in early primates

Primates (Lemurs, Lorises, Tarsiers, Monkeys and Apes)

Contact Info

Product

Resources

About