D. Tab Rasmussen

Oligocene mammals from Ethiopia and faunal exchange between Afro-Arabia and Eurasia

Afro-Arabian mammalian communities underwent a marked transition near the Oligocene/Miocene boundary at approximately 24 million years (Myr) ago. Although it is well documented that the endemic paenungulate taxa were replaced by migrants from the Northern Hemisphere, the timing and evolutionary dynamics of this transition have long been a mystery because faunas from about 32 to 24 Myr ago are largely unknown. Here we report a late Oligocene fossil assemblage from Ethiopia, which constrains the migration to postdate 27 Myr ago, and yields new insight into the indigenous faunal dynamics that preceded this event. The fauna is composed of large paenungulate herbivores and reveals not only which earlier taxa persisted into the late Oligocene epoch but also demonstrates that one group, the Proboscidea, underwent a marked diversification. When Eurasian immigrants entered Afro-Arabia, a pattern of winners and losers among the endemics emerged: less diverse taxa such as arsinoitheres became extinct, moderately species-rich groups such as hyracoids continued into the Miocene with reduced diversity, whereas the proboscideans successfully carried their adaptive radiation out of Afro-Arabia and across the world.

Paleobiology of the oligopithecines, the earliest known anthropoid primates

Anthropoid primates of the subfamily Oligopithecinae are late Eocene in age, and have a known distribution of Northeast Africa and the Arabian Peninsula. Body sizes of the three known oligopithecine species are estimated from allometric molar size regressions to be 700–1000 g forOligopithecus savagei, 600–900 g forCatopithecus browni, and 500 g for the least well-known and smallest species,Proteopithecus sylviae. Occlusal features of the molar teeth, considered in conjunction with body size, suggest that all three species were frugivorous and insectivorous. The orbital size ofCatopithecus indicates a diurnal activity cycle. A relatively broad interobital region in this species may indicate prosimian-like or callitrichid-like olfactory adaptations. Structural features of the crushed skull suggest thatCatopithecus had a smaller cranial capacity than those of extant anthropoids with a similar body size. Fossil plants and birds from localities yielding oligopithecines suggest a wet, warm, tropical, forested, swampy environment. These paleobiological inferences about the extinct oligopithecines are discussed in relation to questions about primate adaptations near the prosimian-anthropoid transition.

The phylogenetic position ofMahgarita stevensi: protoanthropoid or lemuroid?

This comparative study of the cranial and dental morphology ofMahgarita stevensi, which includes description of new fossil material, is designed to address hypotheses concerning the phylogenetic position ofMahgarita with respect to the Anthropoidea and tooth-combed prosimians (Lemuriformes, including Lorisoidea).Mahgarita shares with Oligocene anthropoids and primitive platyrrhines a complex assemblage of structural features that do not occur together in any tooth-combed prosimians; they include a large promontory canal and reduced or absent stapedial canal, a pneumatized petromastoid, a lateral transverse intrabullar septum and probable absence of a free annular ectotympanic, synostosed mandibular symphysis with a transverse torus, a short deep maxilla, maxillomaxillary contact on the inferior orbital margin, an upper canine with a mesial groove, a pronounced nasal spine of the palatine bone, and detailed similarities in occlusal features of the upper molars and other teeth.Mahgarita shares with tooth-combed prosimians several primitive euprimate characters, such as lack of postorbital closure and absence of intrabullar trabeculae. Previous conclusions thatMahgarita is related closely to living strepsirhines were based on a small number of primitive, gradistic features. Cranial characters that have been presented in favor of a tarsiiform-anthropoid clade are analyzed with respect toMahgarita and primitive anthropoids. The results suggest that, among known prosimians,Mahgarita is the one most closely related to the Anthropoidea.

Evolutionary History of Lorisiform Primates

We integrate information from the fossil record, morphology, behavior and molecular studies to provide a current overview of lorisoid evolution. Several Eocene prosimians of the northern continents, including both omomyids and adapoids, have been suggested as possible lorisoid ancestors, but these cannot be substantiated as true strepsirhines. A small-bodied primate, Anchomomys, of the middle Eocene of Europe may be the best candidate among putative adapoids for status as a true strepsirhine. Recent finds of Eocene primates in Africa have revealed new prosimian taxa that are also viable contenders for strepsirhine status. Plesiopithecus teras is a Nycticebus-sized, nocturnal prosimian from the late Eocene, Fayum, Egypt, that shares cranial specializations with lorisoids, but it also retains primitive features (e.g. four premolars) and has unique specializations of the anterior teeth excluding it from direct lorisiform ancestry. Another unnamed Fayum primate resembles modern cheirogaleids in dental structure and body size. Two genera from Oman, Omanodon and Shizarodon, also reveal a mix of similarities to both cheirogaleids and anchomomyin adapoids. Resolving the phylogenetic position of these Africa primates of the early Tertiary will surely require more and better fossils. By the early to middle Miocene, lorisoids were well established in East Africa, and the debate about whether these represent lorisines or galagines is reviewed. Neontological data are used to address the controversial branching sequences among extant lorisid clades. Data from the skin and scent glands, when integrated with other lines of evidence, suggest that Asian and African lorisines share a common lorisine ancestry. The hypothesis of an African clade containing both pottos and galagos to the exclusion of Asian lorisines is less tenable. True galagines are found in the fossil record of Namibia, while true lorisines are known from the Miocene of Asia. The hypothetical branching sequences can be integrated with behavioral and morphological features to develop an adaptive model of lorisoid divergence. By specializing on two different foraging modes early in their radiation, lorisines and galagines subsequently underwent a chain of integrated evolutionary changes eventually having an impact on many components of locomotor behavior, anatomy, physiology, reproduction, life history, and social behavior. Ongoing evolutionary studies of extant galagines are illuminating population phenomena and processes of speciation in an ecological context.

Diet and Feeding Behavior of Mysore Slender Lorises

We studied the feeding ecology of the Mysore slender loris (Loris lydekkerianus lydekkerianus) for 10.5 mo in a dry scrub forest at Ayyalur Interface Forestry Division, Tamil Nadu, South India. We recorded and analyzed 1240 feeding incidents, which indicate that the lorises were almost exclusively faunivorous, with 96% of all feeding events representing animal prey. Of prey items that could be identified (n = 605), 62.9% were ants and termites. Lorises fed on ≥9 orders and 17 families of insects, plus spiders, molluscs, and small vertebrates. Lorises infrequently fed on gums and a legume pod. They usually grabbed prey with one hand, while other appendages firmly held the substrate. Many of the identifiable prey items belong to insect taxa likely to contain toxic chemicals. Consumption of insects inferred to be toxic was accompanied by an elaborate behavioral repertoire of sneezing, slobbering and urine-washing. A high proportion of insects eaten by slender lorises (71%) occurred in patches or aggregations. The utilization of aggregated social insects may have implications for understanding the unusually high degree of gregarious behavior exhibited by the lorises.

ECOMORPHOLOGICAL DIVERSITY AMONG PALEOGENE HYRACOIDS (MAMMALIA): A NEW CURSORIAL BROWSER FROM THE FAYUM, EGYPT

Abstract A new genus and species (Antilohyrax pectidens) of gazelle-sized hyracoid from the late Eocene, Jebel Qatrani Formation, Fayum Province, Egypt, exhibits dental, cranial and postcranial specializations unique among hyracoids. The lower incisors are broad, hyper-pectinate teeth similar to those of the extant dermopteran genus Cynocephalus. Upper incisors are apparently absent, and the shape of the premaxilla suggests that the lower incisors occluded against an upper fibrous pad, as in Cynocephalus and ruminants. The cheek teeth are dominated by sharp-edged, crescentic shearing blades, suggesting a folivorous diet. The articulation between the astragalus and navicular is furrowed and condylar in shape, allowing notable midtarsal flexion and extension but limited lateral movement. The tibia and fibula are fused together throughout most of their length. In size and proportions, limb elements resemble those of the extant springbok (Antidorcas marsupialis, Bovidae). Functional inferences derived from these features suggest a cursorial browser, a Paleogene analog to the bovids that do not appear in Africa until the Miocene. The new genus and species adds another adaptive dimension to what was already an extremely diverse record of Tertiary hyracoids, and further underscores that hyracoids were the dominant terrestrial ungulates of the African Paleogene.

Earliest Known Procaviid Hyracoid from the Late Miocene of Namibia

Despite the great diversity of known fossil hyracoids that belong to the archaic family Pliohyracidae, practically nothing has been unravelled about the origin and diversification of the modern family Procaviidae (containing four genera of Pliocene to Recent age). A new species of procaviid hyrax is reported from Namibian cave breccias dating to the earlier part of the late Miocene. The new species is represented by dental, postcranial, and fragmentary cranial specimens. Despite its 1.0 x 10 7 -year age, the new hyracoid cannot be generically distinguished from the modern genus Heterohyrax. The new species differs from extant H. brucei in its less molarized anterior premolars, and its molar cusps that are slightly more inflated basally. The possible relevance of the new fossil for the origin and radiation of the family Procaviidae is discussed.

Ptolemaia from West Turkana, Kenya

Abstract New fossil material assigned to Ptolemaia cf. grangeri (Mammalia: Ptolemaida) from the late Oligocene site of Nakwai, West Turkana, Kenya, is described and discussed. Recovery of these specimens represents the first record of Ptolemaia from sub-Saharan Africa, and extends the known geographic range of members in this genus southward by about 3,000 km. The Nakwai collection is comprised of two maxillary fragments, a partial mandible with p3 and p4, and an edentulous jaw preserving alveoli for p2-m3. Results from comparisons involving the new material support previous work highlighting convergent similarities between members of Ptolemaia and aardvarks.

Susan Cachel (ed): Primate and Human Evolution

Cachel declares, “I am an apostate from primatology.” By this she means that, in her view, “the behavioral ecology of living non-human primates yields no special insight into the origins of human intelligence, tool behavior, or sociality.” This claim is staked on the very first page of her preface, and is repeated often through the volume. But I disagree with Cachel, not necessarily in her conclusion, but in her pedagogical claim of apostasy; in Primate and Human Evolution she demonstrates very well how primatology is a powerful tool to help dissect what is human from what is not, and how we have gained great insight into the relationships among sociality, body size, diet, locomotion, reproduction, cognition (and everything else we are curious about in humans) from the integrated study of nonhuman primates. Cachel intended Primate and Human Evolution for use in college courses, specifically targeting advanced undergraduates and graduate students. The first 6 chapters comprise a primer in basic primatology with overviews of the history of evolutionary theory and primatology, the primate fossil record, speciation and extinction, and anatomy and behavior. Chapter 7 is stated by Cachel to be a linchpin between the first and second halves of the book, but oddly, it consists of an annotated list of 29 features of the catarrhine substrate: attributes of OldWorld monkeys and apes that form the foundation for evolutionary events leading to human evolution. Chapters 8 through 18 form the intellectual substance of the book, and it is here that students will find plenty of stimulating topics for discussion and further exploration. The most visible common thread running through these diverse chapters is the question: What makes human intelligence different from that of other primates? The answer, according to Cachel, is that humans underwent selection for natural history intelligence, an idea following from her previously published ideas on this subject going back more than a decade (Cachel 1994). Primate and Human Evolution is her most thorough presentation of the theory of natural history intelligence, though after reading the book, the concept of natural history Int J Primatol (2007) 28:1461–1463 DOI 10.1007/s10764-007-9208-7

The evolutionary context of human economics

Non-human animals are faced with intricate choices demanding rational decisions in order to ensure that they gross energetic and nutritional returns sufficient to cover the costs of movement, predator defense, reproduction, and physiological maintenance. The study of these complex relationships (ecology) is similar in many ways to the study of human economics, and the similarity perhaps reflects underlying common mechanisms relevant to the origins of human economy. In the behavioral sciences, extrapolating from non-human primates to humans is potentially hazardous—one runs the risk of excessively anthropomorphizing non-human species, of implying hard-wired genetic control for humans, or of making up “just so” stories to explain human attributes by facile analogy to non-humans. Despite these problems, there is growing recognition that an ability to make intricate, rational, economic-type decisions predicated on context is an attribute shared by many non-human and human beings alike. Palaeoanthropology illuminates the unique evolutionary and cultural history of human beings, which when integrated with ecological and behavioral studies, may allow us to generate hypotheses about origins and distinctive attributes of human economy.