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.     

福建润楠属一新种

描述了福建润楠属(樟科)一新种,即汀州润楠。     

A fossil fruit wing of Dipterocarpus from the middle Miocene of Fujian, China and its palaeoclimatic significance

Dipterocarpus zhengae sp. nov. is described from the middle Miocene Fotan Group of Zhangpu county, Fujian Province, Southeast China on the basis of a fruit wing. Three kinds of venation of the calyx longer lobes (enlarged sepals) occur in the winged fruits of extant Dipterocarpus. The fossil species is referred to the kind having three primary veins and within that category is most similar to extant Dipterocarpus gracilis Blume in the size of the longer lobe as well as its venation. The occurrence of the fruit wing of Dipterocarpus, together with palynological evidence, indicates unequivocally that a tropical climate and tropical rain forest occurred in Zhangpu during the middle Miocene, warmer and more humid than at the present day. The palaeobiogeography of Dipterocarpus is reviewed.     

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。     

福建中中新世紫萁属(紫萁科)的一个新种

丰富的化石记录显示中生代和新生代紫萁属在北半球广泛分布.本文描述了发现于福建中中新世佛昙群的紫萁属一新种:漳浦紫萁(Osmunda zhangpuensis Z.X.Wang and B.N.Sun,sp.nov.).化石小羽片保存完好,呈线状披针形,边缘具齿,羽状脉序.在该属现生种中,当前化石种与现生种Osmunda...     

The diversity and paleoenvironmental significance of Calophyllum (Clusiaceae) from the Miocene of southeastern China

Abstract

Three species within the genus Calophyllum collected from middle Miocene Fotan Group sediments in Zhangpu County, Fujian, southeastern China are described in this paper. These fossils include Calophyllum zhangpuensis sp. nov., Calophyllum striatum, and Calophyllum suraikholaensis. The new fossil species C. zhangpuensis sp. nov. is oval, possesses entire leaves with closely spaced parallel secondary veins and has a round, or slightly retuse, apex. These specimens represent the first known fossil records of this relative wide leaf-type form of Calophyllum from China and have a length:width (L:W) ratio less than 3:1. In combination with the known modern geographic distribution and habitats of this wide leaf-type Calophyllum and other plants, data suggest that the middle Miocene Fotan flora is indicative of a warm climate. Thus, based on available fossil data, we speculate that this genus probably originated in India during the Paleocene before spreading from India to Bangladesh and into China, Sumatra, Malaysia, Indonesia, and Java during the Neogene, leading to its modern distribution. At least, the 3 fossil species in this region can explain floristic exchange between India, Fujian, and South China, which is consistent with previous studies; the occurrence of these 3 species indicates that Calophyllum began to diversity in China no later than the Miocene.     

Tsuga shimokawaensis,a new species of permineralized conifer leaves from the Middle Miocene Shimokawa Group,Hokkaido, Japan

Silicified pinaceous leaves from the late Middle Miocene bed of Shimokawa Town, central Hokkaido, Japan are described asTsuga shimokawaensis sp. nov. Comparisons with leaves of extant species ofTsuga show that the new species is assigned to sect.Tsuga, resembling the extant speciesT. heterophylla in having usually one-cell-layered hypodermis, andT. sieboldii in having mesophyll cells between the resin canal and the hypodermis. From cladistic analyses we infer thatTsuga shimokawaensis is positioned the basal in sect.Tsuga and that sect.Tsuga comprises four species groups.     

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.     

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.     

Anatomical and developmental study of petrified Quercus (Fagaceae) fruits from the Middle Miocene, Yakima Canyon, Washington, USA

The first reported petrified acorns to show internal anatomical structure are here described from Middle Miocene (～15.6 million years old) chert of the Columbia River Basalt Group in Yakima Canyon, Washington. Quercus hiholensis Borgardt et Pigg sp. nov. is described from anatomical and morphological fruit features, as well as a little recognized anatomical feature, the umbilical complex. Acorns, each comprising a nut and its cupule, are up to 15.3 mm long and 18.8 mm wide with helically arranged, imbricate, tuberculate cupule scales. They show basal aborted ovules, short styles, broad stigmas, and lack grooves in their cotyledons. These characters and the developmental pattern seen in these fossil acorns demonstrate that Q. hiholensis conforms to genus Quercus (Fagaceae), subgenus Quercus, section Quercus (the white oaks). The correspondence of Q. hiholensis to the modern section Quercus reveals that the derived floral and fruit characters that distinguish section Quercus within the genus had evolved by the Middle Miocene.     

Middle Miocene Cephalotaxus (Taxaceae) from Yunnan,Southwest China,and its implications to taxonomy and evolution of the genus

The infrageneric taxonomy of the genus Cephalotaxus Siebold et Zuccarini ex Endlicher (Taxaceae) is controversial as morphological characters have been doubted to change coherently among species. Although the epidermal features are considered as important characters in the taxonomy of conifers, they have not been systematically studied in this genus. Neogene foliage shoots with well-preserved epidermal structure not only can provide systematic links to the extant species, but also have implications for the taxonomical definition of the extant species by their epidermal features. In this paper, the morphologies of leafy shoots combining epidermal structure of a Neogene Cephalotaxus, which was collected from the middle Miocene of Southwest China, and ten extant species (variants) were studied. Morphology as well as epidermal structures was compared among species (variants) in Cephalotaxus. Based on the comparisons, the taxonomical definition of extant species in genus Cephalotaxus are discussed. Our results indicate that leaf morphological characters in combination with the features of epidermal structure can distinguish species in genus Cephalotaxus. The fossil foliage shoots from the middle Miocene of Southwest China were assigned to a new species, C. maguanensis n. sp., which shows close affinities to the extant C. hainanensis. On the basis of leaf and epidermal information, we suggest there are seven extant species in Cephalotaxus. With global cooling and the uplift of the Qinghai-Tibet Plateau since the middle Miocene, the cooling climate induced the differentiation and southward expansions of C. maguanensis, and its extant offspring, C. hainanensis, is distributed to Hainan Island and the Indo-Chinese peninsula.     

A new species of the rhinoceros Alicornops from the Middle Miocene of the Linxia Basin, Gansu, China

A new species of the genus Alicornops, A. laogouense , from Laogou in Hezheng County, Linxia Basin, Gansu, China, is described. It is mid-sized in the subfamily Aceratheriinae, but is the largest known species of Alicornops . It represents the first discovery of the genus in Asia. The Middle Miocene fauna bearing A. laogouense is contemporaneous with the Dingjiaergou fauna of Tongxin, Ningxia, China, and its age corresponds to MN 6 in Europe. The discovery of A. laogouense in the Linxia Basin implies that Alicornops dispersed from Europe to Asia. During MN 6 times it was relatively widespread throughout Eurasia. Alicornops laogouense lived in open woodland rich in lakes and rivers.     

New material of Hispanotherium matritense (Rhinocerotidae, Perissodactyla) from Laogou of Hezheng County (Gansu, China), with special reference to the Chinese Middle Miocene elasmotheres

New rhinocerotid teeth from Laogou in Hezheng (Gansu, China) are described and identified as Hispanotherium matritense. Comparing the other Chinese Middle Miocene elasmotheres with material of H. matritense from Iberian localities and Laogou, we confirm the synonymy proposed previously for the species Hispanotherium lintungensis, Tesselodon fangxianensis, Caementodon tongxinensis and Huaqingtherium qiui. The larger size of Hispanotherium tungurense proves that it is a different species from H. matritense. The age of Laogou fauna corresponds to MN6. Paleoenvironments of H. matritense in China include rivers and lakes, which are somewhat different from the arid environment in the Iberian Peninsula. The origin of the Hispanotherium lineage may be in southwestern Europe. After that, it dispersed eastward to Asia.     

High diversity of Lauraceae from the Oligocene of Ningming,South China

Lauraceae is among the largest and floristically most important woody plant families in subtropical and tropical zones. However, the Cenozoic fossil records of Lauraceae are mostly from mid-latitude regions. Here we described eight lauraceous species from the Oligocene of Ningming, Guangxi, South China on the basis of leaf compressions with cuticular structure, providing new evidence for high diversity of Lauraceae in the low latitude region of the northern hemisphere during the late Paleogene. The extant genera to which the Ningming Oligocene fossils are possibly closely related include Cinnamomum, Neolitsea, Litsea, Alseodaphne, Laurus, and Beilschmiedia. All of these extant genera except Laurus still exist in Guangxi today, whereas Laurus is currently distributed in the Mediterranean and adjacent regions. A cladistic analysis based on leaf architectural and leaf cuticular characters for Paleogene Lauraceae species in the world indicated a possible relationship between European and East Asian Paleogene species.     

Merychippus (Mammalia, Perissodactyla, Equidae) from the Middle Miocene of state of Oaxaca, southeastern Mexico

Mexican material referable to Merychippus from two localities in eastern Oaxaca was described first nearly 50 years ago. Subsequent work there and in Central Oaxaca, spanning some 30 years, has allowed to establish the detail stratigraphy in both regions, and assembled a collection of merychippine material from the Matatlán (Central Oaxaca) and El Camarón (eastern Oaxaca) Formations, both K-Ar dated ~15 Ma (late early Barstovian). Detailed taxonomic analysis of this collection indicate the presence of two subhypsodont horse species referable to “Merychippus” cf. “M.” primus and “M.” cf. “M.” sejunctus in both regions. These records document the coexistence in tropical southern North America of basal and hipparionine affinity merychippine grade species, and provide a glimpse in to the diversity of subhypsodont equids in this region.     

A Miocene flora from the Toupi Formation in Jiangxi Province,southeastern China

Here we report a fossil flora from the Miocene Toupi Formation in Jiangxi Province, southeastern China, including megafossil genera Pinus, Podocarpus, Calocedrus, Cinnamomum, Quercus, Lithocarpus, Carya, Palaeocarya, Acer, and Yua. Among them, Yua jiangxiensis n. sp. is the first fossil record of the genus in Asia. A palynological analysis in this study reveals that the palyno-assemblage contains Selaginella, Pteris, Pinus, Picea, Quercus, Fagus, Carya, Ilex, and Rutaceae. Based on Integrated Plant Records (IPR) vegetation analysis, it is suggested that the fossil flora represents an evergreen broad-leaved forest, and the occurrence of tropical and subtropical Cinnamomum supports a warm and moist climate in the region during the middle Miocene.     

First fossils of Zygogynum from the Middle Miocene of Central Yunnan,Southwest China,and their palaeobiogeographic significance

The collision of Gondwana and Laurasia effected plant exchanges between the two continents and thus affected the evolution of the flora of Yunnan, Southwest China. Consequently, the plant diversity in Yunnan has been enriched such that it has attracted the attention of botanical researchers. In this paper, we describe winteraceous fossil leaves collected from the Middle Miocene in Central Yunnan. Compared with the leaves of today’s plants, they share cuticular features and leaf morphological characters with Zygogynum Baillon (Winteraceae); the fossil plant is designated as a new species, Zygogynum poratus n. sp. Liang and Zhou. Based on its historical and recent distribution, the genus probably had migrated into Yunnan from Gondwana during or before the Middle Miocene, spreading beyond its current geographic range.     

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.     

New fossil fruits of Carya (Juglandaceae) from the latest Miocene to earliest Pliocene in Tennessee,eastern United States

Fossil fruits including nuts and associated husk valves of a new species of Carya (Juglandaceae) are described from the latest Miocene to earliest Pliocene in northeastern Tennessee, eastern United States. The husk valves are elliptic, 1.2–4.5 mm thick, with a convex exterior face and a concave interior face; the nuts are globose to ovoid in shape, smooth and longitudinally ribbed on exterior surface, with a short protruding apex and a slightly 4-angled base; inner ribs, lacunae and primary septa are well-developed, while secondary septa are absent or weakly developed. The combination of these carpological characteristics clearly shows a close resemblance to the genus Carya in Juglandaceae. Detailed comparisons of carpological morphology and anatomy indicate that the present fossil taxon is different from both living and most other fossil species of the genus, and therefore warrants the designation of a new fossil species, Carya tennesseensis Huang et al., sp. nov. Carya tennesseensis displays a carpological similarity to C. ventricosa from the late Oligocene to early Pliocene in Europe, suggesting a potential species exchange of the genus between Europe and southeastern North America during the late Neogene. The new fossil species represents one of the few fruit fossil species of Carya from its modern distribution range in southeastern North America. It provides crucial information for better understanding the rapid diversification of the genus from the late Miocene to early Pliocene, and the origin and establishment of today's Carya biodiversity in this region.     

A ctenodactylid rodent (Mammalia: Rodentia) from the Middle Miocene of Chios Island (Greece)

Field work carried out in 1991 and 1993 at the Middle Miocene locality of Thymiana (Chios Island, Greece), produced much rodent material including a number of ctenodactylid dental specimens. They represent a single taxon whose upper and lower cheek tooth morphology clearly differs from Prosayimys flynni and all Sayimys species known so far, except for Sayimys intermedius. The ctenodactylid teeth from the Middle Miocene of Chios are identified as pertaining to the latter species, despite minor differences from the Pakistani and Saudi Arabian representatives of S. intermedius.