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1.
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.  相似文献   

2.
Species definition and delimitation is a non-trivial problem in evolutionary biology that is particularly problematic for fossil organisms. This is especially true when considering the continuity of past and present species, because species defined in the fossil record are not necessarily equivalent to species defined in the living fauna. Correctly assigned fossil species are critical for sensitive downstream analysis (e.g., diversification studies and molecular-clock calibration). The marine snail genus Alcithoe exemplifies many of the problems with species identification. The paucity of objective diagnostic characters, prevalence of morphological convergence between species and considerable variability within species that are observed in Alcithoe are typical of a broad range of fossilised organisms. Using a synthesis of molecular and morphometric approaches we show that two taxa currently recognised as distinct are morphological variants of a single species. Furthermore, we validate the fossil record for one of these morphotypes by finding a concordance between the palaeontological record and divergence time of the lineage inferred using molecular-clock analysis. This work demonstrates the utility of living species represented in the fossil record as candidates for molecular-clock calibration, as the veracity of fossil species assignment can be more rigorously tested.  相似文献   

3.
Icacinaceae are well represented in the modern tropical flora of East Asia, but this family has no confirmed macrofossils from this region. Most of the unambiguous fossils (e.g., endocarps) are from the Paleogene of North America and Europe, where the family is no longer present. Here we report a fossil endocarp of the liana genus Iodes from the Oligocene Wenshan flora, southwestern China. The fossil is relatively large (ca. 20 mm length, 11 mm width) and documents a vascular bundle inside the endocarp wall, a pattern of ridges enclosing few areoles, and an asymmetrical apex and rounded base. On the basis of these characteristics, we described a new species, Iodes elliptica, which represents the first Icacinaceae fruit fossil record from Asia. This fossil, consistent with recent reports of Iodes pollen from the Eocene of Hainan, indicates a long-standing presence of the genus in SE Asia, dating back to the Paleogene. Based on the climatic data of modern Iodes, and other fossil occurrences from Wenshan, we hypothesize that the climate in the region was subtropical during the Oligocene, supporting a rainforest, with an overall mixed regional flora of subtropical and tropical elements.  相似文献   

4.
Several silicified ovulate cones from the late middle Miocene (Barstovian) represent a new species, Picea wolfei Crabtree. This is the second species of Picea for which structurally preserved seed cones are known to be reported from the Tertiary. The cones are 5.0–8.0 cm long and 1.5–2.0 cm at their greatest diameter. Ovuliferous scales are inserted helically around the cone axis and are recurved at their point of divergence. Each scale is broadly obovate to spatulate with a rounded apex and bore two seeds adaxially. The bract subtending the scale is 4.5–7.3 mm long and is fused to the scale for 1.4–2.0 mm. Each bract has an inflated keel-like base which projects abaxially between the seeds of adjacent scales. The fossil cones superficially resemble those of the extant Picea breweriana, yet differ from them anatomically. The new species also resembles Picea lahontense, a fossil compression from the Miocene Trout Creek Flora of south-central Oregon, but the different modes of preservation preclude meaningful comparison. Picea diettertiana, the only structurally preserved fossil cone of this genus previously described, is quite dissimilar in that it lacks a sclerotic pith.  相似文献   

5.
Testate amoebae and the fossil record: issues in biodiversity   总被引:4,自引:0,他引:4  
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6.
Body-weight estimates of fossil primates are commonly used to infer many important aspects of primate paleobiology, including diet, ecology, and relative encephalization. It is important to examine carefully the methodologies and problems associated with such estimates and the degree to which one can have confidence in them. New regression equations for predicting body weight in fossil primates are given which provide body-weight estimates for most nonhominid primate species in the fossil record. The consequences of using different subgroups (evolutionary “grades”) of primate species to estimate fossil-primate body weights are explored and the implications of these results for interpreting the primate fossil record are discussed. All species (fossil and extant) were separated into the following “grades”: prosimian grade, monkey grade, ape grade, anthropoid grade, and all-primates grade. Regression equations relating lower molar size to body weight for each of these grades were then calculated. In addition, a female-anthropoid grade regression was also calculated for predicting body weight infernales of extinct, sexually dimorphic anthropoid species. These equations were then used to generate the fossil-primate body weights. In many instances, the predicted fossil-primate body weights differ substantially from previous estimates.  相似文献   

7.
A fossil flora from the Late Paleocene-Early Eocene Thyra Ø Formation of eastern North Greenland (paleolatitude 77° N) has yielded monocotyledon leaf impressions with characters seen only in the closely related modem species in the families of Heliconiaceae, Musaceae, and Strelitziaceae. The combination of large costae widths and parallel, nonanastomosing, lateral veins that depart at right angles from the costae in the fossil material are features present only in leaves of extant species from these families. Three basic venation patterns also are recognized in the modem species of these families, but except for the genera Strelitzia and Phenakospermum, none of these patterns are present exclusively in any one family. Musopsis n. gen. is created for the fossil material from Greenland, but it is considered a form genus due to the lack of gross morphological features that can be used for separating leaves of the modem genera in Heliconiaceae, Musaceae, and Strelitiziaceae. It is the first known Arctic occurrence of fossil leaf material resembling this modem group of taxa.  相似文献   

8.
Both the fossil record and molecular data support a long evolutionary history for the Araceae. Although the family is diverse in tropical America today, most araceous fossils, however, have been recorded from middle and high latitudes. Here, we report fossil leaves of Araceae from the middle-late Paleocene of northern Colombia, and review fossil araceous pollen grains from the same interval. Two of the fossil leaf species are placed in the new fossil morphogenus Petrocardium Herrera, Jaramillo, Dilcher, Wing et Gomez-N gen. nov.; these fossils are very similar in leaf morphology to extant Anthurium; however, their relationship to the genus is still unresolved. A third fossil leaf type from Cerrejón is recognized as a species of the extant genus Montrichardia, the first fossil record for this genus. These fossils inhabited a coastal rainforest ~60-58 million years ago with broadly similar habitat preferences to modern Araceae.  相似文献   

9.
The early history of Panorpidae (Mecoptera) is poorly known due to sparse fossil records. Up to date, only nine fossil species have been described, all from the Paleogene, except the Early Cretaceous Solusipanorpa gibbidorsa Lin, 1980. However, we suggest S. gibbidorsa is too incompletely preserved to permit even family classification. A new genus with two new species, Jurassipanorpa impunctata gen. et sp. n. and Jurassipanorpa sticta sp. n., are described based on four well-preserved specimens from the late Middle Jurassic Jiulongshan Formation of Daohugou, Inner Mongolia, China. These two new species are the earliest fossil records of Panorpidae. The new genus is erected based on a combination of forewing characters: both R1 and Rs1 with two branches, 1A reaching posterior margin of wing distad of the forking of Rs from R1, and no crossveins or only one crossvein between veins of 1A and 2A. In all four specimens, long and robust setae ranging from 0.09 to 0.38 mm in length and pointing anteriorly, are present on anal veins of forewings. The function of these setae is enigmatic.  相似文献   

10.
Paliurus favonii Unger is recognized and described based on fruits from the Oligocene Ningming flora of Guangxi, South China. Characteristics of the present specimens include circular winged fruits that are 10.0–11.5 mm in diameter with a central endocarp at 3.0 to 4.0 mm in diameter. The specimens fall into the morphological range of the fossil species P. favonii, which has been observed in other Cenozoic sites in the Northern Hemisphere. The present discovery represents the lowest latitude distribution of P. favonii in the world, and we are presenting the first P. favonii fossil described with detailed cuticular characteristics from China. Further, this finding demonstrates that the genus existed in the Oligocene Ningming region, South China, and provides new information for understanding the fossil history. The dispersal mode for winged fossils demonstrates that wind dispersal is well-represented in the Oligocene Ningming flora.  相似文献   

11.
This paper describes three fossil woods, which were firstly found in Zigong city, Sichuan Province, China. The localities of the fossil woods are close to the locality of the famous Dashanpu dinosaur quarry of Zigong. The strata of the fossil woods beating are Xiashaximiao Formation and Xintiangou Formation of the Middle Jurassic, approximately match the strata of the Dashanpu dinosaurs. According to the structures of the secondary xylem, the fossil woods belonged to the primitive conifer genus-Araucarioxylon. Because it was comparatively and obviously different from the other species in this genus, it is assigned as a new species: A. zigongensis. As there was neither fossil leaf nor fossil pollen or spore found in the dinosaur bearing strata before, the discovery of these fossil woods might bear some important significance in the dinosaur research.  相似文献   

12.
Comparative analyses of lipids from fossil plants and from their extant counterparts were undertaken in order to test the taxonomic significance of lipids in palaeobotany. The comparison between lipids from a fossil Ginkgoaceae, Eretmophyllum andegavense, and its extant counterpart, Ginkgo biloba, revealed the presence of original molecules, dimethoxyalkylcoumarins, in lipids from both plants. Such compounds confirm, on chemical grounds the relationship between these extant and fossil Ginkgoaceaes. Moreover, differences in n-alkane distribution between E. andegavense and E. obtusum which are very similar morphologically, confirm that these fossil plants do not belong to the same species. Furthermore, comparative analyses of a fossil Cheirolepidiaceae, Frenelopsis alata, and its extant counterpart, the Cupressaceae Tetraclinis articulata, revealed some similarities between these two species although they do not belong to the same family. Otherwise, comparative analyses of fungi-infected and uninfected samples of F. alata demonstrated that these micro-organisms can significantly affect the chemical composition of fossil plant lipids. In conclusion, even if chemical analyses alone are not sufficient to determine the genus or species of a given fossil plant, they can precise the taxonomy of some specimens that have been previously studied by palaeobotanists.  相似文献   

13.
A sand fly fossil was found in amber; a vegetal resin, which allows all the external phlebotomine structures to be seen. The piece that contains the new species is 14 mm long x 8 mm wide x 3 mm high. All the structures from the head, thorax, and abdomen were examined under the microscope and measured with a calibrated micrometric eyepiece. The morphological aspects of the new species suggest its inclusion in the Pintomyia genus, Pifanomyia subgenus though it is not possible to include it in any of the series known for this subgenus. The presence of two atrophied spines on the gonostyles and gonocoxites without tufts of setae permit the exclusion of the new species from the other species of the subgenus Pifanomyia. The new species is named Pintomyia (Pifanomyia) brazilorum sp. nov.  相似文献   

14.
Analyses of living and fossil taxa are crucial for understanding biodiversity through time. The total evidence method allows living and fossil taxa to be combined in phylogenies, using molecular data for living taxa and morphological data for living and fossil taxa. With this method, substantial overlap of coded anatomical characters among living and fossil taxa is vital for accurately inferring topology. However, although molecular data for living species are widely available, scientists generating morphological data mainly focus on fossils. Therefore, there are fewer coded anatomical characters in living taxa, even in well-studied groups such as mammals. We investigated the number of coded anatomical characters available in phylogenetic matrices for living mammals and how these were phylogenetically distributed across orders. Eleven of 28 mammalian orders have less than 25% species with available characters; this has implications for the accurate placement of fossils, although the issue is less pronounced at higher taxonomic levels. In most orders, species with available characters are randomly distributed across the phylogeny, which may reduce the impact of the problem. We suggest that increased morphological data collection efforts for living taxa are needed to produce accurate total evidence phylogenies.  相似文献   

15.
Estimation of divergence times is usually done using either the fossil record or sequence data from modern species. We provide an integrated analysis of palaeontological and molecular data to give estimates of primate divergence times that utilize both sources of information. The number of preserved primate species discovered in the fossil record, along with their geological age distribution, is combined with the number of extant primate species to provide initial estimates of the primate and anthropoid divergence times. This is done by using a stochastic forwards-modeling approach where speciation and fossil preservation and discovery are simulated forward in time. We use the posterior distribution from the fossil analysis as a prior distribution on node ages in a molecular analysis. Sequence data from two genomic regions (CFTR on human chromosome 7 and the CYP7A1 region on chromosome 8) from 15 primate species are used with the birth-death model implemented in mcmctree in PAML to infer the posterior distribution of the ages of 14 nodes in the primate tree. We find that these age estimates are older than previously reported dates for all but one of these nodes. To perform the inference, a new approximate Bayesian computation (ABC) algorithm is introduced, where the structure of the model can be exploited in an ABC-within-Gibbs algorithm to provide a more efficient analysis.  相似文献   

16.
All previous records of fossil Anthomyiidae are shown to be unsubstantiated. A female anthomyiid of a new genus and species is hereby described from a piece of Dominican amber (Upper Eocene-Oligocene). Character analysis suggests that the fossil, Coenosopsites poinari gen. & sp. nov. , belongs to a Neotropical clade with two recent genera, Phaonantho Albuquerque and Coenosopsia Malloch. Evidence for a sister-group relationship between Coenosopsites poinari and the genus Coenosopsia is provided. Clades are the only acceptable units of phylogenetic classification. Combining fossil and recent clades in phylogenetic classification requires them to be temporally delimited. Proper application of phylogenetic definitions is essential for this purpose. It is proposed that the units of phylogenetic classification should be taxa for recent clades and plesia for fossil clades. A taxon is defined as node-based with reference to its recent species, while a plesion is defined as apomorphy-based. The term lineage is proposed for a recent clade defined as stem-based with reference to its recent sister group. Individual recent species represent clades that can be incorporated into phylogenetic classification as minimal taxon units. Individual fossil species may not represent clades and thus do not count as proper units of phylogenetic classification. However, the names of fossil species are readily construed also to signify plesia with the fossil species as their only known component. As such, they are proper units of phylogenetic classification.  相似文献   

17.
18.
This analysis of all known African larger mammals of the past 10 Myr offers new perspectives on the geographical circumstances of speciation. Our central question is: does the fossil evidence support the idea that most new species start as small populations and, if true, how long is the average growth interval until species are established at their mean later size? This simple question is important to unravelling the competing claims of rival models of speciation. We approached it by direct use of fossil data, which, to our knowledge, has not been done previously. We compared the numbers of fossil site records, as a proxy for magnitude of geographical spread, between survivorship intervals across all species. The results show that the average mammal species has indeed started its life in a relatively small population, and thereafter increased rapidly in geographical spread to reach its long-term equilibrium abundance by about 1 million years after origin. Some theoretical implications of these results are discussed.  相似文献   

19.
1923年A.W.Grabau通过对山东省莱阳盆地莱阳组早白垩世昆虫化石的研究,命名了我国第1种鞘翅目化石昆虫(Proteroscarabaeus yeni).此后,中国昆虫化石分类学者先后发表了40余篇关于我国中生代鞘翅目化石昆虫的分类论著,共描述鉴定了182种,涉及35科,137属.这些化石分布于12个省,其中三叠纪11个种,侏罗纪68个种,白垩纪103个种.本文通过图表列举出我国已发现的中生代鞘翅目化石昆虫名录以及它们的分布和年代,总结了国内中生代甲虫化石当前的研究状况,并初步分析了研究中存在的一些问题.另外本文还介绍了国外学者对于中国古昆虫学者所建立的4个新科提出的不同意见.  相似文献   

20.
Iribarne, O. O., Pascual, M. S. & Zampatti, E. A. 1990 04 15: An uncommon oyster breeding system in a Late Tertiary Patagonian species. Lethaia , Vol. 23 , pp. 153–156. Oslo. ISSN 0024–1164.
The brooding extant species Ostrea puelchana has a breeding system that is unique among living oysters. Females larger than 55 mm often carry small epidictic males (up to 30 mm) on the anterior edge of the concave shell. These are strongly attached when small, but become relatively less strongly attached as they grow larger. Field experiments show that their growth is retarded as a result of the influence of the carrier. Advantages of this mating system are reflected in the success of fertilization; sperm transfer is facilitated safely during long periods of the oyster's life. A similar attachment pattern was found in a fossil oyster, Ostrea aluarezi , from a Patagonian deppsit. The finding suggests that this particular reproductive strategy had already evolved among late Tertiary ostreids. * Epibiotic. breeding system, fossil , Ostrea alvarezi, oyster, Tertiary .  相似文献   

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