Evolution and extinction of Afro-Arabian primates near the Eocene-Oligocene boundary

Revised age estimates for the primate-bearing localities of the Jebel Qatrani Formation (Fayum area, northern Egypt) have provided a new perspective on primate response to early Oligocene climate change in North Africa. Environmental changes associated with early Oligocene cooling might have driven the local extinction of at least 4 strepsirrhine primate clades (adapids, djebelemurines, plesiopithecids and galagids). Contrary to previous suggestions, oligopithecid (and possibly proteopithecid) anthropoids persisted beyond the Eocene-Oligocene boundary (EOB) in the Fayum area, and the former group evidently continued to diversify through the early Oligocene at lower latitudes. Propliopithecids and parapithecine parapithecids first appear in the Jebel Qatrani Formation millions of years after the EOB, so their derived dental and gnathic features can no longer be interpreted as sudden adaptive morphological responses to earliest Oligocene climatic events. Evidence for latitudinal contraction of Afro-Arabian primate distribution through the early Oligocene suggests that the profound late Oligocene restructuring of Afro-Arabian primate communities is most likely to have occurred in equatorial and low-latitude tropical Africa.     

Hindlimb of a giant terrestrial bird from the upper Eocene, Fayum, Egypt

Eremopezus eocaenus Andrews, 1904 is a giant groundbird from upper Eocene deposits of the Fayum, Egypt, which has hitherto been known from non-diagnostic fragmentary material. New fossils collected from quarry L-41 of the Jebel Qatrani Formation include two well-preserved distal tarsometatarsi and an associated whole tarsometatarsus and distal tibiotarsus that allow a more precise evaluation of the phylogenetic position and tarsal function of Eremopezus. Unlike most ratites, the distal tarsometatarsus has a patent distal foramen and a slight hallucal digit. The trochlea for digits II and IV are only slightly reduced in size, are splayed to the right, and the heads lack deep grooving. These features resemble the condition seen in BalaenicepsSagittarius, suggesting active use of the toes in grasping or manipulation, rather than the condition in graviports and cursors, which have reduced medial and lateral trochleae often with distinct grooving of the heads. The limb is relatively long and gracile, another difference from graviports. There is no compelling evidence to link Eremopezus to any known ratite lineage, to the Phorusrhacoidea, or to the extinct predatory birds of the Eocene (e.g. Diatryma, Gastornis). We suggest that Eremopezus represents an endemic African group that independently attained large size and flightlessness.     

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.     

Earliest record of a parapithecid anthropoid from the Jebel Qatrani formation, Northern Egypt

A fifth anthropoid (= anthropoidean, simian or simiiform) genus and species from the late Eocene Fayum Quarry L-41, Abuqatrania basiodontos gen. et sp. nov., further augments the already remarkable primate diversity from this locality and provides the first convincing extension of the enigmatic family Parapithecidae into the oldest productive vertebrate fossil-bearing stratum of the Jebel Qatrani Formation. A. basiodontos exhibits no clear autapomorphies nor any apomorphies that are shared exclusively with any other parapithecid species, and it is most parsimoniously interpreted as the sister taxon of a Qatrania-Parapithecus-Apidium clade. Reevaluation of two contemporaries of A. basiodontos, Serapia and Arsinoea, suggests that neither genus should be ranked as a basal parapithecid. Serapia is more derived than primitive parapithecids in the morphology of the lower fourth premolar and exhibits greater overall similarity to Proteopithecus in cusp placement and the shape and proportions of its lower teeth; accordingly, we place Serapia in the family Proteopithecidae. Arsinoea is much more problematic and does not fit well with any hitherto known Afro-Arabian anthropoid group; we place this genus in a new anthropoid family, Arsinoeidae.     

A highly derived anomalurid rodent (Mammalia) from the earliest Late Eocene of Egypt

Abstract: A new genus and species of diminutive anomalurid rodent, Shazurus minutus, is described on the basis of 15 isolated teeth from the earliest late Eocene (approximately 37 Ma) Birket Qarun Locality 2 in the Fayum Depression of northern Egypt. Shazurus is surprisingly specialized for its age, being most similar in dental morphology to early Miocene Paranomalurus and extant Anomalurus, and is quite different from the roughly contemporaneous anomaluroid genera Nementchamys and Pondaungimys from Algeria and Myanmar, respectively. Parsimony analysis of dental features places Shazurus within crown Anomaluridae as a sister group of two species of Paranomalurus to the exclusion of extant Anomalurus and Idiurus. The marked morphological differences between the two oldest Afro‐Arabian anomaluroids (Shazurus and Nementchamys) suggest that the taxa share a much more ancient common Afro‐Arabian ancestor, possibly derived from Zegdoumyidae. Isolated teeth of Shazurus and other Eocene anomaluroids reveal little about their palaeobiology, but the complete absence of Anomaluroidea from the younger (late Eocene to early Oligocene) Jebel Qatrani Formation is presumably a reflection of environmental change through the late Eocene in northern Africa.     

Ichnofossils and rhizoliths of the nearshore fluvial Jebel Qatrani Formation (Oligocene), Fayum Province, Egypt

The ichnofossils and rhizoliths of the Oligocene Jebel Qatrani Formation of Egypt are among the best preserved, most diverse in form, and most abundant of such structures yet recognized in fluvial rocks. Twenty-one forms are described. The ichnofauna contains traces (domichnia, fodinichnia, cubichnia) of probable annelid, insect, crustacean, and vertebrate origin. These include the first described fossil nest structures and gallery systems of subterranean termites (Isoptera), the first examples of Ophiomorpha from wholly fluvial rocks, and the first fossil vertebrate burrows from the African Tertiary. Rhizoliths associated with the ichnofauna and those occurring elsewhere document a variety of small, wetland plants, coastal mangroves, and much larger trees. The environment suggested by these traces is consistent with the coastal, tropical to subtropical, monsoonal rain forest, with adjacent more open areas, that is indicated by independent evidence of sedimentology, paleontology, and paleopedology.     

Fish remains from the Plio-Pleistocene Shungura Formation, Omo River basin, Ethiopia

Thousands of vertebrate fossils have been recovered from the lower Omo River Valley, in southern Ethiopia, however, fishes have been poorly reported. Here we describe fossil fish remains deriving from the Shungura Formation, part of the Omo Group of deposits ranging in date from 1.8 to 3.4 my. Two new species are reported, Sindacharax omoensis (Characiformes) and Lates arambourgi (Perciformes), which suggest greater diversity of these genera than previously documented.     

Ostracods from the marginal coastal Lower Cretaceous (Aptian) of the Central Tunisian Atlas (North Africa): Paleoenvironment,biostratigraphy and paleobiogeography

This work provides the first detailed taxonomic study of ostracod species from the Lower Cretaceous (Aptian) marginal coastal deposits of the Central Tunisian Atlas, the Kebar Formation, as well as biostratigraphic, paleoecological and paleobiogeographic implications. The ostracod fauna provides new insights into the depositional environment and biostratigraphic framework of the Kebar Formation, and is represented mainly by freshwater and brackish-water species among them, Perissocytheridea tunisiatlasica nov. sp., is newly described. The environmental setting of this formation comprises marginal-littoral conditions in its lower part, thus not exclusively non-marine/continental as assumed previously. The ostracod associations from the studied locality, Jebel Ksaïra, indicate a minimum age of Early Aptian as recently attributed to the lower member of the Kebar Formation based on charophytes (presence of Late Barremian to Early Aptian Globator maillardii var. biutricularis Vicente and Martín-Closas, 2012), whereas an Early Albian age had been previously assigned to the Jebel Kebar site. The relative sea-level fall documented in the lower member of the Kebar formation at Jebel Ksaïra might correspond to the 3rd order cycle major eustatic sea-level fall event starting at the base of the Aptian. Paleobiogeographically, the non-marine ostracod fauna newly discovered in the Kebar Formation shows some affinities to contemporaneous faunas of southern and western Europe, e.g. that of the uppermost Weald Clay Group of southern England (Cypridea fasciata subzone of Horne, 1995), West Africa, and possibly to eastern South America (Brazil). Hence, the studied ostracods further support the hypothesis of supraregional faunal exchange by passive ostracod dispersal during the Early Cretaceous – between Europe and Northern Africa on the one hand, and eastern South America/western Africa and North Africa on the other hand. This leads to the hypothesis that the Peri-Tethyan islands could have worked as effective bridges for non-marine ostracods to become widely dispersed passively by “island-hopping” of larger animals and thus, ultimately, facilitated intercontinental faunal exchanges between South America and Europe – potentially even Asia – via North Africa during the Early Cretaceous.     

The origin and age of haplochromine fishes in Lake Victoria, east Africa

According to a widely held view, the more than 300 species of haplochromine cichlid fishes in Lake Victoria (LV), East Africa, originated from a single founder species in less than 12,000 years. This view, however, does not follow from the published geological and molecular evidence. The former does indeed suggest that the LV basin dried out less than 15,000 years ago, but it does not provide any information about the species that re-colonized the new lake or that remained in the rivers draining the area. The molecular evidence is inconclusive with respect to the origin of the LV haplochromines because cichlids from critical regions around LV were not adequately sampled; and as far as the age of the LV haplochromines is concerned, it in fact led to an estimate of 250,000-750,000 years old. In the present study, mitochondrial DNA (control region) variation was determined by heteroduplex and sequencing analyses of more than 670 specimens collected at widely distributed East African riverine and lacustrine localities. The analyses revealed the existence of seven haplogroups (I-VII) distinguishable by characteristic substitutions. All endemic LV samples tested fell into one of these haplogroups (V) which, however, was also found to be present at various other localities, both riverine and lacustrine, outside LV. Within this haplogroup, four subgroups (VA through VD) could be distinguished, two of which (VB and VC) were represented in LV and at other localities. The great majority of the LV haplochromine species could be classified as belonging to the VC subgroup, which was found only in LV and in the rivers draining into it. Hence, while the endemic haplochromine species of LV could not have originated from a single founding population, the lake does harbour a large species flock which probably arose in situ.     

Mitochondrial phylogeny of the Lamprologini, the major substrate spawning lineage of cichild fishes from Lake Tanganyika in eastern Africa

Lake Tanganyika harbors the oldest, morphologically and behaviorally most diverse flock of cichlid species. While the cichlids in Lakes Malawi and Victoria breed their eggs exclusively by buccal incubation (termed "mouthbrooding"), the Tanganyikan cichlid fauna comprise mouthbrooding and substrate-spawning lineages (fish spawn on rocks, and never orally incubate eggs or wrigglers). The substrate-spawning tribe Lamprologini appears to occupy a key position that might allow one to elucidate the origin of the Tanganyika flock, because five riverine (therefore nonendemic) species from the Zaire River system have been assigned to this tribe, in addition to the lake's endemic species, which make up almost 50% of all 171 species known from this lake (Poll 1986). From 16 species (18 individuals) of the tribe Lamprologini, a 402-bp segment of the mitochondrial cytochrome b gene was sequenced, and, from 25 lamprologine species (35 individuals), sequences from the mitochondrial control region were obtained. To place the Lamprologini into a larger phylogenetic framework, orthologous sequences were obtained from eight nonlamprologine Tanganyikan cichlid species (13 individuals). The Lamprologini are monophyletic, and a clade of six Tanganyikan lineages of mouthbrooders, representing five tribes (Poll 1986), appears to be their sister group. Comparisons of sequence divergences of the control region indicate that the Lamprologini may be older than the endemic Tanganyikan tribe Ectodini, and short basal branches might suggest a rapid formation of lineages at an early stage of the Tanganyika radiation. It is interesting that three analyzed riverine members of the tribe form a monophyletic group; however, they are not the most ancestral branch of the Lamprologini. This might indicate that they are derived from an endemic lamprologine ancestor that left Lake Tanganyika by entering the Zaire River system. These riverine species may not have seeded the Tanganyikan radiation, as currently thought, but may have recently recolonized the river after a long period of isolation, as soon as the lake was connected to the Zaire River again about 2 Mya. Neolamprologus moorii, endemic to Lake Tanganyika, appears to represent the most basal clade of the Lamprologini. Complex breeding behavior, involving the usage of gastropod shells and associated with dwarfism, is likely to have evolved in parallel in several lineages among the Lamprologini. The tribe Lamprologini may be in need of revision, since several genera appear to be polyphyletic.      

THE LATE TRIASSIC BLACK SHALES OF THE GUANLING AREA, GUIZHOU PROVINCE, SOUTH-WEST CHINA: A UNIQUE MARINE REPTILE AND PELAGIC CRINOID FOSSIL LAGERSTÄTTE

Abstract:  Black shales of the lower member of the Carnian Xiaowa Formation (previously known as the Wayao Member of the Falang Formation or as the Wayao Formation) in the Guanling area, Guizhou Province, south-west China, are yielding a rich marine reptile fauna and exceptional remains of pelagic crinoids. The black shales represent deposition on the drowned southern margin of the Yangtze Platform during a Maximum Flooding Interval. The relatively reduced sedimentation rates led to the formation of the Lagerstätte through the accumulation of fossils in the anoxic bottom sediments over a prolonged period of time. Invertebrate fossils represent almost exclusively pelagic forms, such as a diverse ammonite fauna and halobiid bivalves. The spectacular finds of colonies of large (stem lengths > 11 m) crinoids of the genus Traumatocrinus attached to driftwood prove that this crinoid was the first to evolve a pseudoplanktonic life style. The other crinoid is the planktonic roveacrinid Osteocrinus . The marine reptile fauna, represented by probably hundreds of skeletons, is numerically dominated by three species of ichthyosaurs and four species of thalattosaurs. The thalattosaurs fill a palaeobiogeographic gap between the Alpine thalattosaur faunas and those from western North America. Two species of placodonts are rare finds. As for the thalattosaurs, the placodont occurrences greatly expand the geographic range of the group because placodonts have been known previously only from the Mediterranean region, the Alps and the Muschelkalk Basin. The unique abundance of thalattosaurs contrasts with a scarcity of fishes. Although we suggest that the fauna is authochthonous and inhabited surface waters, it must have represented an unusual ecosystem. However, the possibility remains that both the marine reptiles and the Traumatocrinus colonies were concentrated in the region by currents and do not reflect the biocoenosis.     

Conservation of freshwater biodiversity in Oriental Asia: constraints, conflicts, and challenges to science and sustainability

Freshwater ecosystems in Asia are under grave threat. Large and growing human populations and the rapid pace of development have led to the degradation of natural environments throughout the region. Conservation of freshwater biodiversity faces particular challenges because of a lack of public awareness of its magnitude and importance. Even taxa with high public-relations value, such as fishes, are rather poorly known, and the variety of other animals associated with lakes and riverine wetlands, including charismatic and endangered megafauna, seems to have escaped wide attention. The rate and extent of environmental change in Asia are having impacts on the aquatic biota that may be greater than anywhere else on the planet. Particular threats include water pollution, from point and nonpoint sources, which is almost ubiquitous; overharvest of fishes, turtles, and crocodilians; flow regulation and impoundment of rivers; as well as drainage basin degradation and climate change. Many lakes have been so modified by human activities that they function as enormous fishponds, and the introduction of exotic species (especially, but not only, fishes) or the translocation of native taxa has contributed to the extinction of endemic species in isolated drainage basins. The prognosis is grim, and we can anticipate a loss in biodiversity and homogenization of the regional biota. Reversal of these trends will require a change in focus by limnologists and water-resource managers, and the urgent adoption of a conservation agenda for freshwater science in Asia. Received: March 27, 2000 / Accepted: June 30, 2000     

EVOLUTIONARY NOVELTY AND ATAVISM IN THE SEMIONOTUS COMPLEX: RELAXED SELECTION DURING COLONIZATION OF AN EXPANDING LAKE

Fishes of the genus Semionotus diversified in the rift lakes of eastern North America during the Mesozoic (Newark Supergroup). Like the well-known cichlid fishes of the African great lakes, diverse complexes of semionotids were apparently endemic to a number of different lakes. Semionotid fishes show considerable morphological diversity in body shape and in a modified row of scales termed “dorsal ridge scales.” A number of distinct dorsal-ridge-scale patterns characterize groups of species from the Newark Supergroup. Interestingly, about 5.5% of individuals examined have anomalous scales mixed in with otherwise stereotypic dorsal-ridge-scale patterns. In this study, I take advantage of nearly annual stratigraphic resolution to determine whether dorsal-ridge-scale anomalies are concentrated stratigraphically in the early phase of lake formation and colonization by semionotids. More than 1,700 specimens of semionotid fish were collected from a single lake deposit (cycle P4), representing approximately 21,000 years, in the Early-Jurassic Towaco Formation of the Newark Basin. Dorsal-ridge-scale anomalies are significantly more frequent in older than in younger lake sediments, which I interpret as being the result of relaxed selection during the early colonization of the lake. Anomalous variation parallels variation in dorsal ridge scales between species-groups. Some anomalies are atavisms, while others are unique or foreshadow future evolutionary events. One type of anomaly is incorporated into the dorsal-ridge-scale series of two new species that gave rise to a radiation in a subsequent lake filling the same topographic basin. Because both novelties and atavisms occur in the dorsal-ridge-scale series of single individuals, I argue that the disruptions of the same “developmental program” produced both atavistic and novel traits.     

Late Quaternary human settlement patterning in the Jebel Gharbi

This paper presents the latest results of geoarchaeological research on the Upper Pleistocene sequence in the Jebel Gharbi (previously called Jebel Nafusah), a mountain range located in Tripolitania, northwestern Libya. Numerous archaeological sites are found adjacent to springs that formed as a consequence of tectonic activities. The springs originated when Upper Pleistocene earthquakes produced ground displacements that created water outlets, some of which are still active. Springs are spread all along the massif and at the foot of the mountains in Jebel Gharbi. We suggest that they offered attractive resources to populations coming from drier parts of North Africa or the near-by Sahara. The earliest sites associated with the springs include Aterian lithic techno-complexes that have been dated between 80,000 and 40,000 BP. Since then, these springs have attracted many populations, as documented here by settlements belonging to the Later Stone Age (Upper Palaeolithic), Iberomaurusian (Late Upper Palaeolithic or Epipalaeolithic), Neolithic, Roman period, and present time.     

The parasite faunas of meso- and bathypelagic fishes of Norfolk Submarine Canyon, western North Atlantic

A total of 668 specimens representing 18 species of meso- and bathypelagic fishes collected from the western North Atlantic were examined for parasites. Seventeen species and 39.1% of the specimens harboured at least one type of parasite. The highest number of parasite taxa recovered from a single fish species was seven. Host species had overall infection prevalences ranging from 10.0 to 88.9% of the specimens examined. Cestodes were most common (22.8% of all specimens examined), followed by fungi (6.6%), nematodes (6.1%) and digenetic trematodes (4.9%). Mesopelagic fishes showed a greater prevalence of infection (49.1%) than bathypelagic fishes (28.9%). Most parasites recovered were immature; however, based on the presence of adult and postlarval stage parasites, definitive and second intermediate host status is suggested for at least three fish species (Nemichthys scolopaceus, Nessorhamphus ingolfianus and Eurypharynx pelecanoides ). The presence of the cestode Nybelinia and Anisakis-lype nematodes among a number of host species may have been due to predation on the euphausiid Nematoscelis , which was found in the stomachs of all host species infected by these two parasite taxa. Higher overall infection prevalences among host species were found than have been previously reported for mid-water fishes and it is possible that this may be a function of near-bottom presence of the fishes over the continental slope. It is suggested that the low prevalence of parasites within meso- and bathypelagic fishes when compared to benthic and shallow-water species reflects the lower overall energy of, and reduced probability of host-to-host transfer in, the deep-sea pelagic ecosystem.     

Spawning migrations of the endemic Labeobarbus (Cyprinidae, Teleostei) species of Lake Tana, Ethiopia: status and threats

The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning during the rainy season (July to October), whereas eight other species are absent from these rivers and probably developed a new strategy of lacustrine spawning (macro-spatial segregation). One species (L. intermedius) probably spawns in the lake as well as in the rivers. Between the early 1990s and 2000s, the riverine spawners showed a decline of 75% in both biomass and number in both fishery independent surveys and in commercial catches. Reproductive migration makes fishes vulnerable to fisheries and other threats like habitat modifications. Lacustrine spawners are probably more resilient as they are not known to form spawning aggregations that can easily be exploited by fishermen. In addition, upstream rivers and catchments around Lake Tana are highly degraded by erosion and recently subjected to intensive habitat modification for irrigation and hydroelectric power generation. This article reviews results of field studies on the Labeobarbus spawning migration from Lake Tana to spawning rivers, giving emphasis on segregation and homing. It also summarizes existing and emerging threats which form potential causes for the decline of the migratory Labeobarbus species. Knowledge gaps on the reproductive biology are identified for further investigation.     

Phylogeny of the Lake Tanganyika cichlid species flock and its relationship to the Central and East African haplochromine cichlid fish faunas

Lake Tanganyika, the oldest of the East African Great Lakes, harbors the ecologically, morphologically, and behaviorally most complex of all assemblages of cichlid fishes, consisting of about 200 described species. The evolutionary old age of the cichlid assemblage, its extreme degree of morphological differentiation, the lack of species with intermediate morphologies, and the rapidity of lineage formation have made evolutionary reconstruction difficult. The number and origin of seeding lineages, particularly the possible contribution of riverine haplochromine cichlids to endemic lacustrine lineages, remains unclear. Our phylogenetic analyses, based on mitochondrial DNA sequences of three gene segments of 49 species (25% of all described species, up to 2,400 bp each), yield robust phylogenies that provide new insights into the Lake Tanganyika adaptive radiation as well as into the origin of the Central- and East-African haplochromine faunas. Our data suggest that eight ancient African lineages may have seeded the Tanganyikan cichlid radiation. One of these seeding lineages, probably comprising substrate spawning Lamprologus-like species, diversified into six lineages that evolved mouthbrooding during the initial stage of the radiation. All analyzed haplochromines from surrounding rivers and lakes seem to have evolved within the radiating Tanganyikan lineages. Thus, our findings contradict the current hypothesis that ancestral riverine haplochromines colonized Lake Tanganyika to give rise to at least part of its spectacular endemic cichlid species assemblage. Instead, the early phases of the Tanganyikan radiation affected Central and East African rivers and lakes. The haplochromines may have evolved in the Tanganyikan basin before the lake became a hydrologically and ecologically closed system and then secondarily colonized surrounding rivers. Apparently, therefore, the current diversity of Central and East African haplochromines represents a relatively young and polyphyletic fauna that evolved from or in parallel to lineages now endemic to Lake Tanganyika.     

Species compositions and ecology of the riverine ichthyofaunas in two Sulawesian islands in the biodiversity hotspot of Wallacea

This account of the riverine ichthyofaunas from the islands of Buton and Kabaena, off south‐eastern mainland Sulawesi, represents the first detailed quantitative checklist and ecological study of the riverine fish faunas in the biological hotspot of Wallacea. The results are based on analysis of samples collected by electrofishing at a wide range of sites from July to September in both 2001 and 2002. While the fauna was diverse, with the 2179 fishes caught comprising 64 species representing 43 genera and 22 families, the catches were dominated by the Gobiidae (26 species and 25% by numbers), Eleotridae (seven species and 27% by numbers), Zenarchopteridae (three species and 22% by numbers) and Anguillidae (two species and 12% by numbers). The most abundant species were the eleotrids Eleotris aff. fusca‐melanosoma and Ophieleotris aff. aporos, the anguillid Anguilla celebesensis, the zenarchopterids Nomorhamphus sp. and Nomorhamphus ebrardtii and the gobiids Sicyopterus sp. and Glossogobius aff. celebius‐kokius. The introduced catfish Clarias batrachus was moderately abundant at a few sites. Cluster analysis, allied with the similarity profiles routine SIMPROF, identified seven discrete groups, which represented samples from sites entirely or predominantly in either Buton (five clusters) or Kabaena (two clusters). Species composition was related to geographical location, distance from river mouth, per cent contribution of sand and silt, altitude and water temperature. The samples from the two islands contained only one species definitively endemic to Sulawesi, i.e. N. ebrardtii and another presumably so, i.e. Nomorhamphus sp., contrasting starkly with the 57 species that are endemic to Sulawesi and, most notably, its large central and deep lake systems on the mainland. This accounts for the ichthyofaunas of these two islands, as well as those of rivers in northern mainland Sulawesi and Flores, being more similar to each other than to those of the central mainland lake systems. This implies that the major adaptive radiation of freshwater fishes in Sulawesi occurred in those lacustrine environments rather than in rivers.     

The effects of riverine impoundment on genetic structure and gene flow in two stream fishes in the Mobile River basin

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Diets of fossil primates from the Fayum Depression of Egypt: a quantitative analysis of molar shearing

Over the last 90 years, Eocene and Oligocene aged sediments in the Fayum Depression of Egypt have yielded at least 17 genera of fossil primates. However, of this diverse sample the diets of only four early Oligocene anthropoid genera have been previously studied using quantitative methods. Here we present dietary assessments for 11 additional Fayum primate genera based on the analysis of body mass and molar shearing crest development. These studies reveal that all late Eocene Fayum anthropoids were probably frugivorous despite marked subfamilial differences in dental morphology. By contrast, late Eocene Fayum prosimians demonstrated remarkable dietary diversity, including specialized insectivory (Anchomomys), generalized frugivory (Plesiopithecus), frugivory+insectivory (Wadilemur), and strict folivory (Aframonius). This evidence that sympatric prosimians and early anthropoids jointly occupied frugivorous niches during the late Eocene reinforces the hypothesis that changes in diet did not form the primary ecological impetus for the origin of the Anthropoidea. Early Oligocene Fayum localities differ from late Eocene Fayum localities in lacking large-bodied frugivorous and folivorous prosimians, and may document the first appearance of primate communities with trophic structures like those of extant primate communities in continental Africa. A similar change in primate community structure during the Eocene-Oligocene transition is not evident in the Asian fossil record. Putative large anthropoids from the Eocene of Asia, such as Amphipithecus mogaungensis, Pondaungia cotteri, and Siamopithecus eocaenus, share with early Oligocene Fayum anthropoids derived features of molar anatomy related to an emphasis on crushing and grinding during mastication. However, these dental specializations are not seen in late Eocene Fayum anthropoids that are broadly ancestral to the later-occurring anthropoids of the Fayum's upper sequence. This lack of resemblance to undisputed Eocene African anthropoids suggests that the "progressive" anthropoid-like dental features of some large-bodied Eocene Asian primates may be the result of dietary convergence rather than close phyletic affinity with the Anthropoidea.