Dabbling ducks (Aves: Anatidae) from the Middle Miocene of Mongolia

A new genus and two new species of ducks (Aves: Anatidae) from the Middle Miocene Sharga locality are described. Mioquerquedula minutissima gen. et sp. nov. is a very small duck. Anas velox Milne-Edwards, 1868 from the Middle Miocene of France is transferred to the genus Mioquerquedula. Aix praeclara sp. nov. described here is the oldest record of the modern genus Aix. A revision of the previously described small duck Anas soporata Kurochkin, 1976 shows that only the specimens from the Sharga locality should be referred to this species. The status of other small ducks from the Neogene of Europe and North America is discussed. The diversity of herbivorous and diving ducks in the Sharga locality indicates that Miocene Shargyn Govi Lake was rich in food resources.     

A new duck from the Middle Miocene of Mongolia, with comments on Miocene evolution of ducks

A new relatively large duck, Chenoanas deserta gen. et sp. nov. from the Middle Miocene of the Sharga locality, which is morphologically intermediate between the extant genera Chenonetta and Tachyeres, is described. The diversity of Early and Middle Miocene ducks is discussed. It is noted that some Middle Miocene duck remains are incorrectly referred to the genus Mionetta. The distribution of morphological characters of the humerus in Neogene and extant ducks shows that the present day diversity of ducks apparently results from extinction of some taxa which were formed in the Oligocene-Early Miocene. The distribution of morphological characters in the evolution of diving ducks is evidence that not only the formation of different morphotypes but also so-called ??evolutionary maturation?? of taxa also explains the modern diversity.     

Middle Miocene elasmotheriine Rhinocerotidae from China and Mongolia: taxonomic revision and phylogenetic relationships

Eight elasmotheriine rhinocerotid species have been described from the Middle Miocene of China and Mongolia. In this paper a revised taxonomy is presented based on direct observation and comparison of the available material. A phylogenetic analysis based on 282 morphological characters has led to the reappraisal of Procoelodonta Matthew, 1931, Caementodon Heissig, 1972 and Huaqingtherium Huang & Yan, 1983. The genus Procoelodonta is split into three subgenera: P.  ( Procoelodonta ) Matthew, 1931, P.  ( Begertherium ) Beliaeva, 1971, and P.  ( Pasalarhinus subg. n). The genus Caementodon is split into two subgenera: C.  ( Caementodon ) Heissig, 1972 and C.  ( Beliajevina ) Heissig, 1974. Four species are assumed to have occurred in the Middle Miocene within the area studied: Procoelodonta ( Procoelodonta ) mongoliense (Osborn, 1924), ' P. ' ( Begertherium ) borissiaki (Beliaeva, 1971), ' Caementodon ' ( Beliajevina ) fangxianense (Yan, 1979) and Huaqingtherium lintungense (Zhai, 1978) (=' Caementodon tongxinensis ' Guan, 1988 =' Huaqingtherium qiui ' Guan, 1993 =' Hispanotherium tungurense ' Cerdeño, 1996). Shennongtherium hypsodontus Huang & Yan, 1983 is removed from the Elasmotheriina, owing to dental characters which suggest that it is a teleoceratine. The distribution of the main characters later seen in Elasmotherium is briefly discussed. The persistence and diversity of the Elasmotheriina throughout the Middle Miocene help explain how minute brachyodont animals gave rise to the mammoth-sized hypsodont Elasmotherium.     

Nacholapithecus skeleton from the Middle Miocene of Kenya

An almost entire skeleton of a male individual of Nacholapithecus kerioi (KNM-BG 35250) was discovered from Middle Miocene (approximately 15 Ma) sediments at Nachola, northern Kenya. N. kerioi exhibits a shared derived subnasal morphology with living apes. In many postcranial features, such as articular shape, as well as the number of the lumbar vertebrae, N. kerioi resembles Proconsul heseloni and/or P. nyanzae, and lacks suspensory specializations characteristic of living apes. Similarly, N. kerioi shares some postcranial characters with Kenyapithecus spp. However, despite the resemblance, N. kerioi and Proconsul spp. are quite different in their body proportions and some joint morphologies. N. kerioi has proportionally large forelimb bones and long pedal digits compared to its hindlimb bones and lumbar vertebrae. Its distinctive body proportions suggest that N. kerioi was more derived for forelimb dominated arboreal activities than P. nyanzae and P. heseloni. On the other hand, it exhibits a mixture of derived and primitive cranio-dental and postcranial features relative to the contemporaneous Kenyapithecus and Early MioceneMorotopithecus. While the phylogenetic position of N. kerioi is unsettled, it seems necessary to posit parallel evolution of cranio-dental and/or postcranial features in fossil and living apes.     

Neogene geese and ducks (Aves: Anatidae) from localities of the Great Lakes Depression, western Mongolia

New material of ducks and geese from Late Miocene-Early Pliocene localities of the Great Lakes Depression in western Mongolia is described and the previously described material is revised. This study confirms the presence of four goose species, four dabbling ducks, and three diving ducks. A large goose previously described as Heterochen vicinus is assigned to a separate genus, Heteroanser. Bonibernicla ponderosa is transferred to Anserinae, and North American Branta woolfendeni is regarded as a junior synonym of Bonibernicla ponderosa. The validity of two goose species, Anser devjatkini and A. liskunae, is confirmed and both are assigned here to the subgenus Chen. It is also shown that the holotype of Anas molesta actually belongs to a diving duck of the genus Aythya. The presence of Anas soporata in the Hyargas Nuur Formation is not confirmed.     

New palaeothentid marsupial from the Middle Miocene of Bolivia

The new species Acdestis maddeni is described based on the most complete skull of a palaeothentid marsupial known so far. The skull preserves most of the upper dentition and of the ear region, the latter an anatomical region previously unknown in this extinct family. A right maxillary fragment including C–M2 also belongs to the new species. The specimens come from the middle Miocene localities of Rosario and Quebrada Honda in southernmost Bolivia. The generic allocation of the new species is somewhat problematic, given that most of the taxonomy of fossil palaeothentids is based on lower dentitions. Compared to that of caenolestids, the skull of A. maddeni is much larger, with a shorter and broader snout, a proportionally narrower interorbital constriction, and a less globular, more triangular–shaped braincase in dorsal view.     

Ctenodactylids from the Lower and Middle Miocene of Saudi Arabia

The ctenodactylids from the Lower and Middle Miocene of Saudi Arabia are represented by two species: Sayimys intermedius (Sen and Thomas, 1979) and Sayimys assarrarensis sp. nov. This new taxon differs from the other species of Sayimys by its larger size together with an association of characters such as the presence of a metalophulid II in d4 and the strength of the anteroloph and posteroloph in P4. A cladistic analysis involving Prosayimys flynni , Sayimys obliquidens , S. assarrarensis sp. nov., S. intermedius, S. sivalensis, S. baskini , and Metasayimys curvidens is provided. Sayimys assarrarensis sp. nov. nests between Sayimys obliquidens and Metasayimys curvidens as a relatively primitive taxon.     

New fossil crocodilians from the Middle/Upper Miocene of Tunisia

New crocodilian material from the Beglia Formation (Middle/Upper Miocene) of Tunisia, although fragmentary, is reported. However, due to its fragmentary nature very little can be said about its affinities, and only the genus Euthecodon can be identified with certainty.     

Middle Miocene dispersals of apes

The earliest record of fossil apes outside Africa is in the latest early Miocene of Turkey and eastern Europe. There were at least 2, and perhaps 4, species of ape, which were found associated with subtropical mixed environments of forest and more open woodland. Postcranial morphology is similar to that of early Miocene primates and indicates mainly generalized arboreal quadrupedal behaviours similar to those of less specialized New World monkeys such as Cebus. Robust jaws and thick enamelled teeth indicate a hard fruit diet. The 2 best known species of fossil ape are known from the site of Pa?alar in Turkey. They have almost identical molar and jaw morphology. Molar morphology is also similar to that of specimens from Germany and Slovakia, but there are significant differences in the anterior teeth of the 2 Pa?alar species. The more common species, Griphopithecus alpani, shares mainly primitive characters with early and middle Miocene apes in Africa, and it is most similar phenetically to Equatorius africanus from Maboko Island and Kipsaramon. The second species is assigned to a new species of Kenyapithecus, an African genus from Fort Ternan in Kenya, on the basis of a number of shared derived characters of the anterior dentition, and it is considered likely that there is a phylogenetic link between them. The African sites all date from the middle Miocene, similar in age to the Turkish and European ones, and the earliest emigration of apes from Africa coincides with the closure of the Tethys Sea preceding the Langhian transgression. Environments indicated for the African sites are mixtures of seasonal woodlands with some forest vegetation. The postcrania of both African taxa again indicate generalized arboreal adaptation but lacking specialized arboreal function. This middle Miocene radiation of both African and non-African apes was preceded by a radiation of arboreal catarrhine primates in the early Miocene, among which were the earliest apes. The earliest Miocene apes in the genus Proconsul and Rangwapithecus were arboreal, and because of their association with the fruits of evergreen rain forest plants at Mfwangano Island, it would appear that they were forest adapted, i.e. were living in multi-storied evergreen forest. The same or similar species of the same genera from Rusinga Island, together with other genera such as Nyanzapithecus and the small ape Limnopithecus, were associated with plants and animals indicating seasonal woodland environments, probably with gallery forest forming corridors alongside rivers. While the stem ancestors of the Hominoidea were almost certainly forest adapted, the evidence of environments associated with apes in the later part of the early Miocene and the middle Miocene of East Africa indicates more seasonal woodlands, similar to those reconstructed for the middle Miocene of Pa?alar in Turkey. This environmental shift was probably a requisite for the successful emigration of apes out of Africa and made possible later movement between the continents for much of the middle Miocene, including possible re-entry of at least one ape lineage back into Africa.     

A new middle Miocene pliopithecid from Inner Mongolia, China

In addition to the new fragments of the Omo I skeleton, renewed fieldwork in the Kibish Formation along the lower reaches of the Omo River in southwestern Ethiopia has yielded new hominin finds from the Kibish Formation. The new finds include four heavily mineralized specimens: a partial left tibia and a fragment of a distal fibular diaphysis from Awoke's Hominid Site (AHS), a parietal fragment, and a portion of a juvenile occipital bone. The AHS tibia and fibula derive from Member I and are contemporaneous with Omo I and II. The other specimens derive from Chad's Hominid Site (CHS), and derive from either Member III or IV, which constrains their age between approximately 8.6 and approximately 104ka.     

福建漳浦中中新世几种藓类植物研究*

亚洲新生代藓类植物化石非常稀少,漳浦琥珀是目前已知的我国低纬度地区唯一含苔藓植物化石的新生代琥珀矿床。漳浦琥珀源自中中新世气候适宜期(~14-17 Ma)的龙脑香树脂,温暖潮湿的热带季雨林气候和广泛分布的龙脑香科植物,为藓类植物的生长、多样性演化和三维立体保存提供了条件。本研究共报道了漳浦县中中新世藓类植物化石3个属种,包括:白发藓属Leucobryum Hampe、牛舌藓属Anomodon Hook.et Taylor和扁枝藓属Homalia(Brid.)B.S.G.。首次利用三维X射线断层扫描技术(Micro-CT)研究了白发藓属化石,发现其与现生种短枝白发藓Leucobryum humillimum Cardot非常相似,因此将其命名为短枝白发藓(相似种)Leucobryum cf.humillimum。此外,当前牛舌藓属Anomodon和扁枝藓属Homalia化石是东亚地区的首例记录。漳浦琥珀中的藓类植物化石揭示了中中新世时期苔藓植物的多样性,丰富了东亚低纬度地区新生代苔藓植物的化石记录。     

New Middle Miocene Caviomorph Rodents from Quebrada Honda,Bolivia

The rodents of the middle Miocene fauna of Quebrada Honda Bolivia are described. The most abundant rodent is the chinchillid Prolagostomus sp. More precise identification of this species will require revision of early to middle Miocene lagostomines, taking into account variation in modern populations. The next most common rodents are the tiny octodontoid Acarechimys, sp. nov.?, and the caviid Guiomys unica. The Acarechimys species may be unique to Quebrada Honda, but verification awaits revision of this geographically and temporally widespread genus. Guiomys unica is a recently described species otherwise known only from two Patagonian localities, El Petiso and Río Chico. Two rodents are unique to Quebrada Honda. Mesoprocta hypsodus, gen. et sp. nov., is a dasyproctid distinguished by its very hypsodont, cement-covered cheek teeth. Quebradahondomys potosiensis, gen. et sp. nov., is an adelphomyine echimyid distinguished by the less oblique lophids of its trilophodont cheek teeth, among other features. The rodents of Quebrada Honda are more similar to those of Patagonia than those of northern South America, paralleling patterns seen in other mammal groups from this fauna.     

EM-studies on Salviniaceae Megaspores from the Middle Miocene Fasterholt Flora,Denmark

Reproductive organs of Salvinia and Azolla were found together with other small plant remains in the Middle Miocene Fasterholt flora, Denmark. They were examined by the use of SEM and TEM; this was done with the three species of Azolla for the first time. Salvinia is represented by one, or possibly two, species. The megaspore of S. cerebrata has a characteristic surface sculpture of irregular, rounded ridges. Some specimens differ from the typical S. cerebrata by having strongly developed verrucae or clavae. They are described as Salvinia sp., but it is possible that they represent a variety of S. cerebrata. Azolla is represented by three species. A. nikitinii and A. ventricosa have nine floats in two tiers; massulae have not been found. A. tuganensis has three floats in one tier, massulae have anchor-shaped glochidia.     

Fossil leaves of Populus from the Middle Miocene of Yunnan,SW China

Today southern Yunnan, SW China, has a tropical or subtropical climate and seasonal rainforests. In the past, some temperate elements were also present. In this paper, a new species of Populus is reported from the Middle Miocene deposits in Zhenyuan. Its leaves are ovate or ovate-suborbicular, with serrate margins. They have a shallowly cordate to cuneate base without glands, short acuminate apex, and salicoid teeth with spherical glands. The veins are glabrous but unicellular hair bases occur on the lower epidermis of the lamina. Stomata are confined to the lower epidermis. The presence of Populus in the Middle Miocene of the region indicates an expansion of the genus into low-latitude Asia in the late Cenozoic and a more complicated history of vegetational change in southern Yunnan than has so far been assumed.     

New Middle Devonian radiolarians from western Mugodzhary

A new genus, Palaeoellipsoides gen. nov., and three new species, Palaeoellipsoides convexocylindratus sp. nov., P. planoconvexus sp. nov., and Palaeodiscaleksus shuldakensis sp. nov. of Givetian radiolarians from the Kurkuduk and Shuldak formations on the Shuldak River (western Mugodzhary) are described.     

Quantitative reconstruction of palaeoclimate from the Middle Miocene Shanwang flora, eastern China

The fossil leaf flora from the Shanwang Formation, Linqu County, Shandong Province, eastern China, is diverse, abundant, well preserved and discretely spaced, all of which make it suitable for the recognition and application of leaf physiognomic characters. This article is the first study of Chinese Tertiary floras using the CLAMP (Climate Leaf Analysis Multivariate Program) approach. Numerous bedding planes yield leaf assemblages through over 20 m thickness of diatomaceous shales within the Middle Miocene Shanwang Formation. The diatomaceous shales, containing abundant fossils, have been divided into 19 units. A working platform (3×3 m) in the Diatomite Quarry of Shanwang was studied for about 3 months in 1998 and as many fossils as possible were recorded layer by layer. This collecting method, used for the first time in the history of Shanwang research, enabled us to record the presence or absence of megafossils in distinct units so that we could investigate leaf physiognomic characteristics and palaeoclimate for each time interval. Leaf fossils from six units (5, 6, 7, 13, 15 and 16) have been used to estimate palaeoclimate parameters of the Shanwang area using the CLAMP 3B dataset. The predicted climate is that of a lakeside setting, at over 1000 m above sea level and within the 17–15-Ma time interval. Meteorological factors have been estimated using the CLAMP approach, including mean annual temperature (MAT; 9.5–11.2°C), warmest month mean temperature (20.2–22.5°C), growing season length (5.9–6.8 months), mean growing season precipitation (83–165 cm) and relative humidity (73–79%). MAT estimates from leaf margin analysis (LMA) range from 12.5 to 15.2°C, which are a maximum of 4° higher than those from our CLAMP analyses and from previous results of LMA studies of the Shanwang flora (10–13°C). Nearest living relatives (NLR) of other biota (pollen, fish, insects, diatoms, microthyriaceous fungi, etc.) indicate warm and moist temperate to subtropical conditions in the Shanwang area during the Miocene. CLAMP predictions are similar to the climate predicted from NLRs although the MAT prediction is a few degrees cooler. The fact that the Shanwang leaf flora is from a lacustrine sequence may have biased the CLAMP analysis towards cooler (and possibly wetter) climates. The modern Yangtze River valley is a reasonable environmental analogue for the Shanwang Middle Miocene, though Shanwang may have had cooler summers, cooler MAT and less seasonality in rainfall. The climate was essentially constant during deposition of the sequence studied, with possible minor variations in precipitation.     

A dragonet (Perciformes: Callionymidae) from the Middle Miocene of southern Russia

From the Middle Miocene (Konkian) deposits in the Taman Peninsula, a new genus and species of dragonets Protonymus gontsharovae gen. et sp. nov. are described, differing from all known recent and fossil members of the family in the structure of the preopercular spine, radialia of pectoral fins, and of otolith (sagitta). The history of dispersal of dragonets in the Paleogene-Neogene is discussed.