A new large Pliocene colobine species (Mammalia: Primates) from Asa Issie, Ethiopia

The Colobinae (Mammalia: Primates) are relatively unknown from the African middle to late Miocene. When they appear in the Pliocene they are unambiguous and already fairly diverse taxonomically, geographically, and ecologically. Discoveries from Pliocene sediments in eastern and southern Africa document a radiation of large-bodied colobines very different from those known today. Paleontological research in Ethiopia has recently led to the discovery and identification of another large-bodied colobine species from the early Pliocene site of Asa Issie, discovered in 2000. This new colobine is larger than but morphologically very similar to its sister taxon Kuseracolobus aramisi, an older taxon also described from the Middle Awash. This new species has significant implications for our understanding of the Pliocene colobine adaptive radiation.     

The Hand of Cercopithecoides williamsi (Mammalia,Primates): Earliest Evidence for Thumb Reduction among Colobine Monkeys

Thumb reduction is among the most important features distinguishing the African and Asian colobines from each other and from other Old World monkeys. In this study we demonstrate that the partial skeleton KNM-ER 4420 from Koobi Fora, Kenya, dated to 1.9 Ma and assigned to the Plio-Pleistocene colobine species Cercopithecoides williamsi, shows marked reduction of its first metacarpal relative to the medial metacarpals. Thus, KNM-ER 4420 is the first documented occurrence of cercopithecid pollical reduction in the fossil record. In the size of its first metacarpal relative to the medial metacarpals, C. williamsi is similar to extant African colobines, but different from cercopithecines, extant Asian colobines and the Late Miocene colobines Microcolobus and Mesopithecus. This feature clearly links the genus Cercopithecoides with the extant African colobine clade and makes it the first definitive African colobine in the fossil record. The postcranial adaptations to terrestriality in Cercopithecoides are most likely secondary, while ancestral colobinans (and colobines) were arboreal. Finally, the absence of any evidence for pollical reduction in Mesopithecus implies either independent thumb reduction in African and Asian colobines or multiple colobine dispersal events out of Africa. Based on the available evidence, we consider the first scenario more likely.     

Dental eruption sequence among colobine primates

Dental development is one aspect of growth that is linked to diet and to life history but has not been investigated among colobines since the work of Schultz [1935]. This study establishes the dental eruption sequence for several colobine species and compares it to that of other catarrhines. The mandibles and maxillae of two hundred and four juvenile colobine specimens were scored for presence or absence of permanent teeth and for stages of partial eruption. Eruption was defined as ranging between tooth emergence (any part of a tooth crown above the alveolar margin) and full occlusion, with three intermediate levels manifest between these boundaries. In African colobines, represented by C. guereza, C. angolensis and P. badius, M2 erupts before I2, and in C. angolensis it also erupts before I1. The canine is delayed, erupting after the premolars in females and after M3 in males. Asian colobines show greater diversity in eruption sequences. Nasalis shows no early eruption of the molars and is very similar to Macaca. In Trachypithecus and Pygathrix M(2) erupts before I(2). The canine in Trachypithecus is delayed, erupting after the premolars and, in some males, after M3. In Presbytis M2 erupts before both incisors; M3 erupts before C in both sexes, and often before both premolars. Although the actual timing of eruption is unknown, all colobine species examined except N. larvatus showed some degree of relatively early eruption of M2 and M3. The lack of this tendency in Nasalis sets this genus apart from all other colobines represented in this study. Dental eruption sequence is thought to reflect life history patterns. Early molar eruption in colobines was thought by Schultz (1935) to be a primitive character reflecting shorter life history. Faster growth rates found in folivorous primates have been interpreted as being related to an adaptation to folivory (Leigh 1994), and early eruption of molars may be part of this dietary specialization. The relationships between dental development and both diet and life history are investigated.     

Dentition ofSivaladapis nagrii (Adapidae) from the late Miocene of India

Two genera and three species of adapid primates are known from the middle and late Miocene of India and Pakistan. Most fossil specimens are fragmentary, but the best-known species, Sivaladapis nagrii,is now represented by enough specimens to permit composite reconstruction of much of the dentition. The incisors of Sivaladapishave spatulate crowns, and the canines are large, projecting teeth. Premolars and molars exhibit complex occlusion involving simultaneous approximation of pointed leading cusps on upper and lower molars, with linear trailing lophs. The premolar eruption sequence in Sivaladapisappears to be P ₂-P₄-P₃, as in most extant prosimians. Symphyseal fusion of the mandibular rami occurred early in ontogeny, before the eruption of any of the anterior permanent teeth. We interpret Sivaladapisto have been a specialized arboreal folivore that became extinct near the end of the Miocene, when the distribution of forests was increasingly restricted and colobine monkeys first invaded South Asia.     

Model of a hypothetical protohominid dentition and its implications for hominid phylogeny

The complete dentition of the common ancestor ofAustralopithecus andHomo, intermediate between that of a pongid and a hominid, is virtually unknown. The maxillary dentition (P3-M2) ofRamapithecus brevirostris Lewis, 1934, a pongid from the Early Pliocene, and that of hominids from the Late Pliocene and Plio/Pleistocene is known. SinceR. brevirostris is probably ancestral to the hominids, a model of intermediate maxillary dentition (P3-M2) is extrapolated and described. The model represents a hypothetical protohominid dentition. It does not conform with the teeth ofAustralopithecus, but shows greater morphological affinity to hominine dentition and to 5 myo hominids. TheHomo lineage, therefore, may go back to the Middle Pliocene. According to the normal sequence of evolution, it is most unlikely thatAustralopithecus gave rise toHomo, but much more probable that a very early, generalizedHomo evolved into an advanced, specializedAustralopithecus.     

Folivory or fruit/seed predation for Mesopithecus, an earliest colobine from the late Miocene of Eurasia?

Here we compare dental microwear textures from specimens of the fossil genus Mesopithecus (Cercopithecidae, Colobinae) from the late Miocene of Eastern Europe with dental microwear textures from four extant primate species with known dietary differences. Results indicate that the dental microwear textures of Mesopithecus differ from those of extant leaf eaters Alouatta palliata and Trachypithecus cristatus and instead resemble more closely those of the occasional hard-object feeders Cebus apella and Lophocebus albigena. Microwear texture data presented here in combination with results from previous analyses suggest that Mesopithecus was a widespread, opportunistic feeder that often consumed hard seeds. These data are consistent with the hypothesis that early colobines may have preferred hard seeds to leaves.     

Miocene cercopithecoidea from the Tugen Hills, Kenya

Miocene to Pleistocene fossiliferous sediments in the Tugen Hills span the time period from at least 15.5 Ma to 0.25 Ma, including time periods unknown or little known elsewhere in Africa. Consequently, the Tugen Hills deposits hold the potential to inform us about crucial phylogenetic events in African faunal evolution and about long-term environmental change. Among the specimens collected from this region are a number of discoveries already important to the understanding of primate evolution. Here, we describe additional cercopithecoid material from the Miocene deposits in the Tugen Hills sequence, including those from securely dated sites in the Muruyur Beds (16-13.4 Ma), the Mpesida Beds (7-6.2 Ma) and the Lukeino Formation (∼6.2-5.7 Ma). We also evaluate previously described material from the Ngorora Formation (13-8.8 Ma). Identified taxa include Victoriapithecidae gen. et sp. indet., cf. Parapapio lothagamensis, and at least two colobines. Specimens attributed to cf. Pp. lothagamensis would extend the species’ geographic range beyond its type locality. In addition, we describe specimens sharing derived characters with modern African colobines (Tribe: Colobina), a finding that is congruent with previous molecular estimates of colobine divergence dates. These colobine specimens represent some of the earliest known members of the modern African colobine radiation and, in contrast to previous hypotheses, suggest that early African colobines were mainly arboreal and that semi-terrestrial Late Miocene and Plio-Pleistocene colobine taxa were secondarily derived in their locomotor adaptations.     

Geopalaeontological setting,chronology and palaeoenvironmental evolution of the Baccinello-Cinigiano Basin continental successions (Late Miocene,Italy)

The Latest Miocene succession of the Baccinello-Cinigiano Basin in southern Tuscany (Italy) recorded a faunal turnover documenting the extinction of an older, insular, endemic faunal complex characterised by the extinct ape Oreopithecus bambolii and the setting of a new, continental, European faunal complex including the colobine monkey Mesopithecus. A similar turnover pattern (Late Miocene ape/Latest Miocene Cercopithecidae) is generally observed in Late Miocene continental successions of Eurasia, from Spain to central Europe, Southwest Europe, the near East, and Southwest Asia. Abundant literature reports that the Late Miocene Eurasian hominoid primate distribution closely tracks the climatic/environmental changes occurring during the 12–9 Ma interval, until their extinction in western Europe. In the primate record, the dispersion of Cercopithecidae and the contraction of hominids is interpreted as an event depicting a pattern of “continentalisation” in the Old World. The sedimentary succession of the Baccinello-Cinigiano basin, one of the longest continuous vertebrate-bearing continental successions in the Neogene Italian record, contributes to the debate on this hypothesis. This paper provides an overview of the main characteristics of the sedimentary succession, the chronological constraints (biochronology, radiometric datings, magnetostratigraphy), and the palaeoenvironmental evolution as derived from palaeobiological approaches and from the study of stable carbon and oxygen isotope contents along the entire sedimentary succession. The 2 myr geological history of the Baccinello Cinigiano Basin, which documents the evolutionary history of Oreopithecus and associated faunas, does not have a direct relation with the event of the Messinian Salinity Crisis. The evolutionary history of Baccinello-Cinigiano Basin and its palaeontological record have been mainly driven by the regional tectonism and palaeogeographic changes that affected the northern Tyrrhenian regions in Late Miocene (Latest Tortonian–Messinian) times.     

Locomotor evolution of <Emphasis Type="Italic">Mesopithecus</Emphasis> (Primates: Colobinae) from Greece: evidence from selected astragalar characters

This paper reports our investigations into functional aspects of the astragalus of four samples of the genus Mesopithecus from Greece. More particularly, it aims to infer substrate preferences of M. delsoni/pentelicus from the Middle Turolian site of Perivolaki (central Greece), M. pentelicus from the late Middle Turolian site of Pikermi (southern Greece), and M. cf. pentelicus and M. cf. monspessulanus from the Late Turolian site of Dytiko (northern Greece). For these purposes, selected astragalar functional features, such as trochlea wedging, proximal facet curvature, and head rotation were expressed as linear measurements on both fossil and selected extant colobines. The size-adjusted measurements were used for univariate comparisons as well as a multivariate principal components analysis. Both approaches revealed that the selected characters were able to discriminate between extant arboreal and semiterrestrial colobines, but all fossil forms presented mosaic morphology. Thus, the oldest representative, M. delsoni/pentelicus was reconstructed as mainly semiterrestrial. On the other hand, the astragalus of M. pentelicus appeared to reflect semiterrestrial habits with a moderate adaptation to arboreality. Similar habitus reconstruction was allocated to the more recent M. cf. pentelicus, whereas the sympatric and synchronous M. cf. monspessulanus showed semiterrestrial adaptations with a slight preference of terrestrial substrates. The results mainly conform to paleoenvironmental reconstructions of the fossiliferous localities and denote that Mesopithecus was mainly a semiterrestrial radiation throughout its evolutionary history, with differential rates of use between arboreal and terrestrial substrates. These adaptations could have promoted the dispersal of the genus throughout Eurasia during the latest Miocene and Early Pliocene.     

The fossil evidence of anthropoid brain evolution

The endocast of Aegyptopithecus, a 27 million year old ape, reveals that its brain was advanced over that of prosimians and comparable to that of modern anthropoids in relative size and in having expanded visual cortex, reduced olfactory bulbs, and a central sulcus separating primary somatic sensory and motor cortex. The early appearance of those features suggests that they may have been among the adaptations responsible for the evolution of anthropoids from prosimian ancestors. The frontal lobe was relatively smaller in Aegyptopithecus than in modern anthropoids. An endocast of Dolichocebus, one of the oldest known New World monkeys (25–30 million years old), reveals visual cortex expanded as in modern anthropoids. The 19 million year old Napak frontal bone displays a hominoid rather than cercopithecoid sulcal pattern. An 18 million year old endocast of the ape Dryopithecus (Proconsul) was neither monkey-like nor primitive, as originally described, but rather apelike and essentially modern in all observable features. The oldest undoubted Old World monkey endocast, from nine million year old Mesopithecus, reveals that the brain was modern in sulcal pattern and proportions. The sulcal pattern was like that of modern colobines, but that appears to be the more primitive condition, from which features characteristic of modern cercopithecine brains have evolved. The brain of six million year old Libypithecus was similar to that of Mesopithecus. A two million year old endocast of “Dolichopithecus” arvernensis displays a modern cercopithecine sulcal pattern.     

Phylogeny and evolution of Loxoconcha (Ostracoda, Crustacea) species around Japan

The pore-systems of 17 extant species of Loxoconcha around Japan were studied in order to understand their phylogeny and evolution. The phylogeny was estimated by two steps. First, the 17 species were divided into two groups, Group A (12 species) and Group B (five species) by Pore pattern Below Eye tubercle (PBE) analysis. Then, intragroup relationships were estimated by Differentiation of Distributional pattern of Pore-system (DDP) analysis. PBE analysis reveals that species of Groups A and B have on average different ecological preferences. Species of Group A, which appeared in the late Pliocene, are more diverse, have both phytal and bottom-dwelling modes of life, possess fewer pore-systems in the ventral area, and inhabit normal marine environments. Species of Group B, whose oldest fossil record is the lower Miocene, are less diverse, have only bottom-dwelling species, possess more pore-systems in the ventral area, and tend to inhabit brackish water environments. The results of this study suggest that the differences in ecology may have had an impact on the late Cenozoic diversification around Japan. The primary invasion of Group B occurred before the lower Miocene,with no subsequent diversification. Group A invaded after the late Pliocene and immediately diversified, which created the present abundance of Loxoconcha species around Japan in both species diversity and variety of modes of life.     

Early Miocene catarrhine dietary behaviour: the influence of the Red Queen Effect on incisor shape and curvature

The early Miocene catarrhine fossil record of East Africa represents a diverse and extensive adaptive radiation. It is well accepted that these taxa encompass a dietary range similar to extant hominoids, in addition to some potentially novel dietary behaviour. There have been numerous attempts to infer diet for these taxa from patterns of dental allometry and incisor and molar microwear, however, morphometric analyses until now have been restricted to the post-canine dentition. It has already been demonstrated that given the key functional role of the incisors in pre-processing food items prior to mastication, there is a positive correlation between diet and incisal curvature (Deane, A.S., Kremer, E.P., Begun, D.R., 2005. A new approach to quantifying anatomical curvatures using High Resolution Polynomial Curve Fitting (HR-PCF). Am. J. Phys. Anthropol. 128(3), 630-638.; Deane, A.S., 2007. Inferring dietary behaviour for Miocene hominoids: A high-resolution morphometric approach to incisal crown curvature. Ph.D. Dissertation. The University of Toronto.). This study seeks to re-examine existing dietary hypotheses for large-bodied early Miocene fossil catarrhines by contrasting the incisal curvature for these taxa with comparative models derived from prior studies of the correlation between extant hominoid incisor curvature and feeding behaviour. Incisor curvature was quantified for 78 fossil incisors representing seven genera, and the results confirm that early Miocene fossil catarrhines represent a dietary continuum ranging from more folivorous (i.e., Rangwapithecus) to more frugivorous (i.e., Proconsul) diets, as well as novel dietary behaviours that are potentially similar to extant ceboids (i.e., Afropithecus). Additionally, early Miocene fossil catarrhine incisors are less curved than extant hominoid incisors, indicating a general pattern of increasing mesio-distal and labial curvature through time. This pattern of morphological shifting is consistent with the Red Queen Effect (Van Valen, L., 1973. A new evolutionary law. Evol. Theory 1, 1-30), which predicts that taxa that are removed from one another by geological time, although potentially having similar diets, may exhibit differing degrees of a similar dietary adaptation (i.e., differing degrees of incisal curvature).     

地黄属分子系统学分析

地黄属是中国准特有属,属内种间关系仍待澄清。该研究基于多个个体的叶绿体与核基因片段对地黄属进行系统发育重建,探讨属内物种分化与可能历史。结果表明:(1)地黄属为单系群,天目地黄为本属原始类群,并与湖北地黄互为姐妹群或连续姐妹群,裂叶地黄-高地黄、地黄-茄叶地黄分别组成姐妹群;(2)多个个体构建的系统树更能揭示本属物种关系的复杂性;(3)祖先分布区重建表明本属经历过3次扩张与2次隔离过程,物种形成过程与历史气候变化密切相关。最后该研究提出了地黄属物种形成研究亟待解决的几个重要问题。     

Orycteropus (Tubulidentata, Mammalia) from Langebaanweg and Baard's Quarry, Early Pliocene of South Africa

Fossil teeth and bones of aardvarks are relatively common at Langebaanweg, an Early Pliocene site in western Cape Province, South Africa. The remains are compatible in size and most details of morphology to extant Orycteropus afer, and are the earliest fossils attributed to this species. Other Late Miocene to Early Pliocene localities in Africa have yielded smaller species of aardvarks, suggesting that the extant lineage evolved in southern Africa. Morphologically the genus Orycteropus has been remarkably conservative since at least the Early Miocene but it witnessed an overall increase in size through the Neogene. The species O. afer has been morphometrically stable since the Early Pliocene. These observations indicate that the evolutionary process in aardvarks is extremely bradytelic. To cite this article: M. Pickford, C. R. Palevol 4 (2005).     

Climate and the evolution of annual/perennial life-histories in Nemesia (Scrophulariaceae)

The Cape Floristic Region and the Succulent Karoo in southwestern Africa are both noted for their plant species richness and high levels of endemism. The southwestern tip of Africa is one of the world's five Mediterranean-type climate regions. The biodiversity in the Cape Floristic Region and Succulent Karoo is thought to be at least partly due to changes to the climate of these regions that have occurred since the middle Miocene. Annual species are usually a significant proportion of local flora in Mediterranean-type climate regions. Previous studies of species radiations in the Cape Floristic Region have concentrated on genera that predominantly contain perennial species. Nemesia (Scrophulariaceae) comprises c. 65 species of annual and perennial herbs and sub-shrubs that are native to southern and tropical Africa. Annuals make up a significant proportion (~75%) of Nemesia species. We have reconstructed a phylogeny of 23 Nemesia species using nucleotide sequences of the ITS, ETS and trnL-spacer regions. Species were grouped into five clades, two composed of annual species, one that contained two annual and one perennial species, one that contained one annual and two perennial species, and one that was predominantly composed of perennial species. Phylogenetic dating of the ITS + ETS based phylogenetic tree using penalised likelihood suggested the genus evolved during the Miocene, and that the majority of extant Nemesia species studied radiated during the Pliocene. Ancestral state reconstruction supports at least three separate origins of the annual habit from plants with a perennial life history. One origin can be traced to the late Miocene while the other two transitions occurred more recently during the Pliocene. The transition from perennial to annual life-histories in Nemesia may have been a response to climate change.     

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.     

Dental variability inSaimiri and the taxonomic status ofNeosaimiri fieldsi,an early squirrel monkey from La Venta,Colombia

Neosaimiri fieldsi, from the South American middle Miocene locality of La Venta, is represented by a relatively complete mandible and dentition that strongly resembles that of extantSaimiri. Comparison with a large sample of mandibles ofSaimiri indicates that this specimen cannot be distinguished from modern populations on the basis of any reportedly diagnostic feature, such as cingulid development, molar length ratio, trigonic/talonid ratio, or mandibular depth. The fossil is best considered an extinct species of the modern genusSaimiri until further material indicates otherwise.     

Diets of two sympatric colobines in Zaire: More evidence on seed-eating in forests on poor soils

Recent studies have shown that the so- called folivorous African colobines eat a significant amount of seeds. There is disagreement as to whether seed-eating is due to the poor quality of tree foliage, due in turn to poor soils, or to the fact that seeds are a normal part of colobine diets. To test these hypotheses, we studied feeding of red colobus monkeys, Colobus badius tholloni,and black-and-white colobus monkeys, Colobus angolensis angolensis,in a tropical rain forest of Central Zaire (Salonga National Park). We conducted studies on soil properties, vegetation composition, and the availability and chemical contents of food plants simultaneously. Soils were very acid, with a high percentage of sand, very low cation exchange capacity, and very low exchangeable bases. The forest was dominated by legumes (45.6% of trees), among which the Caesalpinioideae were the best represented (85%). C. badiusfed mostly on leaves (61%) and seeds (33%), legumes making up 65% of their diet. C. angolensisfed mostly on seeds (50%) and leaves (27%); 39% of their diet came from legumes. The two species tended to select items richer in crude protein or lipids or both. Total phenolics and condensed tannins were abundant in the foliage and seeds but were poor predictors of colobine choice of food. Intersite comparisons show that colobines in Zaire ate a higher proportion of seeds than all other related species so far studied in Africa and that the Salonga forest had among the poorest soils and harbored the highest percentage of Caesalpinioideae. Our results confirm that seed- eating is more common among colobines living in areas where soils are poor. They strongly suggest that this link is mediated through forest composition, especially the abundance of legumes, and that the development of seed- eating results both from the high availability of nutrient-rich seeds and from the poor quality of mature tree foliage.