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1.
Abstract: Chondrichthyans are newly reported from the autochthonous Wordian Khuff Formation (middle Permian), cropping out in well‐exposed, low‐palaeolatitude sections in the interior Haushi‐Huqf area of Oman. The shark remains comprise isolated teeth, dermal denticles and fin spines and have been recovered by processing limestone in buffered acetic acid from bulk rock samples. The fauna consists of mainly ctenacanthiform and hybodontiform taxa, identified as Glikmanius cf. myachkovensis, Glikmanius culmenis sp. nov., Omanoselache hendersoni gen. et sp. nov., Omanoselache angiolinii gen. et sp. nov., cf. Omanoselache sp., Reesodus underwoodi gen et sp. nov., Teresodus amplexus gen. et sp. nov., Gunnellodus bellistriatus, Khuffia lenis gen. et sp. nov., Khuffia prolixa gen. et sp. nov. and Euselachii sp. indet. Additional specimens include rare teeth of the lonchidiid cf. ‘Palaeozoic Genus 1’ sp., of the neoselachian Cooleyella cf. fordi and a further indeterminate neoselachian, of an indeterminate petalodont and of the holocephalan Deltodus aff. mercurei and Solenodus cf. crenulatus. Fin spines add a further two taxa, Nemacanthus sp. and Amelacanthus cf. sulcatus, which have neoselachian affinities and therefore an unclear relationship to the recovered teeth. The occurrence of Nemacanthus within this Wordian fauna represents the oldest record of this taxon and its only known occurrence in the Palaeozoic. Of the remaining genera, Glikmanius has previously been recorded from the Wordian, whereas for all the others, this study represents their youngest known stratigraphic occurrence and first occurrence in Guadalupian (middle Permian) strata. This adds significantly to our knowledge of the global diversity of chondrichthyans preceding the end‐Guadalupian biotic crisis. Palaeogeographically, for all taxa, this study represents the first record from the western fringe of the marine Neotethyan basin, and only Cooleyella was previously known from the southern (Gondwanan) part of the Pangaean continental margin.  相似文献   

2.
The taxonomic status of Rhinolophus macrotis sensu lato (s.l.) in Vietnam and adjacent territories remains problematic. To address this issue, we performed an integrated study of morphological, acoustic, and genetic characters of R. macrotis s.l. specimens and compared these with sympatric species within the philippinensis group (R. marshalli, R. paradoxolophus, and R. rex). Our results reveal that in addition to a cryptic species of R. macrotis previously found in Jiangxi and Jingmen, China, R. macrotis s.l. in continental Asia includes three further species, namely R. cf. siamensis, R. cf. macrotis, and R. cf. macrotis “Phia Oac.” These four taxa are distinguished from genuine R. macrotis in Nepal and R. siamensis in Thailand by their morphological and/or genetic features. Further taxonomic evaluation of the subspecies of R. macrotis s.l. is needed to determine their affinities with recently recognized cryptic species and to possibly describe new taxa. Our results also show that interspecific divergences in mitochondrial DNA sequences (Cytb and COI genes) among taxa within the philippinensis group (particularly between R. cf. siamensis/R. cf. macrotis and R. rex/R. paradoxolophus) are significantly lower than those of other morphological groups in the genus. These phylogenetic patterns might be explained by recent allopatric speciation or ancient introgression events among ancestors of the taxa during the Pleistocene. However, further investigations including genetic analyses of nuclear genes are needed to test the latter hypothesis.  相似文献   

3.
Lungworms from the genus Rhabdias are common parasites of amphibians and reptiles distributed worldwide. To assess the diversity of Rhabdias spp., we performed molecular analyses of 35 specimens sampled in different regions of Brazil. Molecular analyses were based on the internal transcribed spacer (ITS), large subunit (28S) ribosomal and the cytochrome oxidase I (COI) mitochondrial genes. DNA sequence divergence was compared among ribosomal and mitochondrial genes, analyses using the general mixed Yule‐coalescent (GMYC) method based on the COI gene were used to identify possible cryptic diversity, and phylogenetic analyses using concatenated ITS and 28S ribosomal genes were used to test the monophyly of Rhabdiasidae. We revealed five morphospecies: R. cf. stenocephala, R. breviensis, R. pseudosphaerocephala and two new species, Rhabdias sp.4 and Rhabdias sp.5. DNA sequence levels of divergence among genes ITS, 28S and COI were compared, and the efficiency of the molecular markers to identify species (ITS and COI) and lineages (COI) was tested. GMYC was assigned to 17 well‐supported clades (i.e., 17 species), and cryptic diversity was detected in the Neotropical region as evidenced by the multiple lineages in R. breviensis and R. pseudosphaerocephala. In addition, our results suggest evidence for host–parasite cophylogeny in the R. pseudosphaerocephala complex and dispersal events among their populations. Phylogenetic analyses supported the monophyly of Rhabdiasidae and improved the resolution of main clades. Rhabdias breviensis is closely related to Rhabdias cf. africanus, Rhabdias cf. stenocephala, R. pseudosphaerocephala, Rhabdias sp.4 and Rhabdias sp.5 grouping together in a main clade with Neotropical‐related species. The large geographical distribution appeared to be a phylogenetic pattern among the species of Rhabdias from the neotropics.  相似文献   

4.
聂拉木是西藏南部志留纪含笔石地层(石器坡组)的主要产地。近期在该地亚来村新发现一批笔石标本, 包括Normalograptus sp.、Glyptograptus sp.、Campograptus lobiferusC. cf. lobiferus、C. cf. obtususC.? circularisLituigraptus cf. convolutusRastrites cf. perfectusStimulograptus sedgwickiiStreptograptus sp.和Torquigraptus decipiens。该组合面貌确定其属于志留系兰多维列统埃隆阶上部Lituigraptus convolutus带至Stimulograptus sedgwickii带。这一新材料的发现, 使西藏南部的志留纪地层得以作全球对比。  相似文献   

5.
The fossil-rich site within the Albian Escucha Formation in the Oliete Sub-basin, located in the Northeast of Spain, has provided a great abundance of impressions, including leave remains and seed cones of Coniferales (Sphenolepis kurriana, Sphenolepis sternbergiana, Elatides curvifolia, Brachyphyllum sp. and Geinitzia sp. cf. G. rigida), leaves of Caytoniales (Sagenopteris elliptica), Ginkgoales (Ginkgoites pluripartita, and Sphenobaiera sp. cf. S. longifolia), Bennettitales (Ptilophyllum sp. cf. P. pecten and aff. Zamites sp.), Cycadales (Nilssonia tenuinervis and Ctenozamites with entire and denticulate pinnae margins), Czekanowskiales, and reproductive structures of Gnetales. The gymnosperm remains are fairly abundant in the upper member, built up of sediments deposited in fluvial and swamp environments without marine influence. The different gymnosperm associations in this outcrop indicate a wide variety of environments in a subtropical climate, and a mixture of North American and European taxa in the Iberian plate during the Middle Albian.  相似文献   

6.
A plant microfossil assemblage of 24 identified and five unknown pollen and spore types is reported from the early Miocene La Quinta Formation near Simojovel, Chiapas, Mexico. The taxa group into seven paleocommunities representing versions of the modern mangroves (Pelliciera, Rhizophora), swamp and lowland riparian forest (Ceratopteris, Crudia, Pachira), tropical rain forest (Selaginella, cf. Antrophyum, Pteris, Sphaeropteris/Trichipteris, cf. Aguiaria, Crudia, Guarea, Pachira), lower montane rain forest (Alfaroa/Oreomunnea, possibly Eugenia), evergreen cloud forest [Picea, Pinus, Podocarpus, Ericaceae (possibly Cavendishia/Vaccinium)], evergreen seasonal forest (Hymenaea, Ilex, possibly Eugenia), and tropical deciduous forest (Cedrela). Elements of arid and high-elevation habitats were absent or few, and northern temperate elements (Picea, Pinus?) were few or rare. Paleoelevations are estimated at 1000–1200 m (present average 2000 m, maximum 3004 m), MAT (mean annual temperature) at least as warm as the present 24°C, and annual rainfall near the present ∼2500 mm but more evenly distributed. The La Quinta (Simojovel) and other Tertiary floras from the region reflect a trend toward higher altitudes, more seasonal rainfall, cooling tempertures, increased introduction of cool-temperate elements from the north after ∼15 Ma (million years), and increased introduction of tropical elements from the south after completion of the isthmian land bridge ∼3.5 Ma ago.  相似文献   

7.
Recent fieldwork at Woranso-Mille, Ethiopia led to the recovery of an abundant, diverse mammalian fauna that includes remains of the early hominid Australopithecus afarensis. Proboscideans are among the taxa well sampled at the site, primarily by gnathodental specimens, dated to the mid-Pliocene interval of 3.8–3.6 Ma. These fossils document traces of the last anancine gomphotheres (Anancus ultimus) in eastern Africa and several elephant taxa. Comparative study of the elephant fossils indicates the presence of cf. Mammuthus sp. “Hadar-type,” cf. Elephas ekorensis, E. recki brumpti, and cf. Loxodonta adaurora adaurora. Proboscidean evolution in the mid-Pliocene is interesting because during this time archaic elephants were completely replaced by basal members of crown elephant lineages, taxonomic diversity was high (multiple elephant species, anancine gomphotheres, stegodonts, and deinotheres), and elephants were undergoing substantial reorganization of the craniodental masticatory apparatus, presumably in response to the spread of more open habitats and greater competition for grazing resources. The Woranso-Mille sample is important because this interval is only represented elsewhere in eastern Africa by a small number of sites, and because adaptive diversification among early crown elephants requires greater clarification. Morphometric contrasts among the fossil dentition from Woranso-Mille presage the differential success of elephant lineages in eastern Africa during the Pleistocene, providing hints about the beginnings of competitive displacement. Differences between E. recki brumpti from Woranso-Mille and the slightly younger Sidi Hakoma Member of the Hadar Formation reveal the beginnings of continuous, directional morphometric change that characterized the lineage. Reconsideration of E. recki subspecies indicates that they are arbitrary lineage divisions tied to geochronological boundaries (with utility for biochronological correlation at well sampled sites) rather than real phylogenetic entities, but does not reject monophyly or anagenetic evolution of the lineage.  相似文献   

8.
Invertebrate Anisian and Norian reef boulders were found in the Gerence and Güvercinlik Formations, respectively, exposed in northeastern part of the Karaburun Peninsula, western Turkey. Halimedacean green algae and solenoporacean red algae, usually associated with other reef building organisms are described in this paper. The following taxa were determinated: halimedaceans: Egericodium hungaricum Flügel, Velledits, Senowbari-Daryan and Riedel, Aternasus irregularis n. gen., n. sp.; solenoporaceans: Solenopora cf. alcicornis Ott, Solenopora triasina Vinassa de Regny, Solenopora vachardi n. sp., Solenopora concentrica n. sp., Solenopora paraconcentrica n. sp., Tauristorea parallela Senowbari-Daryan and Link, Tauristorea discursa n. sp., and Parachaetetes cassianus (Flügel). The monospecific genus Aternasus n. gen. is the most abundant alga within the Anisian reef boulders. The solenoporaceans are represented by several taxa but the individual species are less abundant. E. hungaricum, T. parallela Senowbari-Daryan and Link, and S. triasina Vinassa de Regny are described from the Norian reef limestones embedded in Güvercinlik Formation, all other taxa from the Anisian reef boulders embedded in the Gerence Formation.  相似文献   

9.

We surveyed the diversity of cultivable fungi isolated from cold and hot volcanic soils of Deception Island, Antarctica. Seventy-four fungal isolates were identified; these belonged to 17 taxa in the genera Aspergillus, Penicillium, Pseudogymnoascus, Purpureocillium, and Mortierella. The fungal assemblages showed low diversity, richness, and dominance indices. The Aspergillus taxa were dominant in the soils at 0 °C, 50 °C, and 100 °C. Aspergillus lacticoffeatus, Aspergillus cf. ruber, Penicillium citrinun, and Purpureocillium sodanum were present only in soils having a temperature of 100 °C. Aspergillus calidoustus was present in all thermal soils and displayed the highest densities. The majority of fungi displayed mesophilic behavior; however, different isolates of Aspergillus lacticoffeatus and Aspergillus niger were able to grow at 50 °C; these are phylogenetically close to the causative agents of aspergillosis in immunocompromised individuals. Deception Island perhaps represents one of the most visited regions in Antarctica and the tourism there has increased over the last 20 years, especially by elderly tourists, probably with weak immune systems, come in contact with the resident microorganisms, including the thermo-resistant opportunistic Aspergillus species.

  相似文献   

10.
Sediments at the Red Hot Truck Stop (RHTS), Mississippi, USA are important because they contain the lowest latitude record of both the earliest known Eocene plant and mammal fossils in North America. The RHTS contains the uppermost Tuscahoma Formation and the lowermost part of the basal Bashi and Hatchetigbee formations. The Tuscahoma Formation is composed of glauconitic sands and silts that represent estuarine to shallow marine sediments. Faunal remains indicate that the RHTS section belongs to the Wasatchian North American land mammal age and specifically to the lower Graybullian subdivision. Pollen and spore floras from the RHTS are moderately diverse (113 taxa) and contain families that today are associated with warm‐adapted vegetation types such as Annonaceae, Bombacaceae, Burseraceae and palms. Eocene first occurrences are represented by Brosipollis sp., Celtispollenites sp., Interpollis microsupplingensis, cf. Nuxpollenites psilatus, Platycarya spp., Retistephanocolporites sp. and Symplocos? contracta and by one genus of pteridophyte spore (Granulatisporites sp.). The overall composition and within‐sample diversity of the sporomorph flora is more similar to the Hatchetigbee Formation (early Eocene) than to the middle Tuscahoma Formation (late Palaeocene) but among‐sample diversity remains unchanged across the Palaeocene/Eocene boundary. The distinct composition of the RHTS demonstrates that floral change across the Palaeocene/Eocene boundary is complex and composed of several phases of floral change.  相似文献   

11.
We describe fish assemblages from the Carboniferous (mid‐ to late Tournaisian) Ballagan Formation at two localities, Hawk's Nib and Mill Hole, on the Isle of Bute, Scotland. Fossil material occurs in thin, locally reworked dolomitic limestone beds, interpreted as the deposits of very shallow lakes or lagoons, developed on, or adjacent to, a seasonally dry coastal plain. The mostly disarticulated fossils comprise isolated teeth, mandibles, scales, tesserae, dermal bones, lepidotrichia and vertebrae. The fauna includes rhizodonts (cf. Archichthys portlocki, cf. Strepsodus sauroides), lungfish (Sagenodus sp.), other sarcopterygians (Megalichthys sp.), one shark (Ageleodus pectinatus), climatiiform acanthodians and indeterminate actinopterygians. The Mill Hole assemblage is especially noteworthy because it includes some putative juvenile forms (Archichthys and Sagenodus). A critical review of the habitat preferences of the documented taxa suggests that most were either euryhaline or, in the case of Archichthys, probably endemic to brackish or freshwater settings. The Bute fish beds fall within a crucial evolutionary period during which many fish and other animal groups were infiltrating nonmarine environments, either passively or actively. It may be that lakes and lagoons may have functioned as protected nurseries for juveniles during this wave of colonization.  相似文献   

12.
Upper Serpukhovian to lower Bashkirian conodonts studied from the lower and middle part of the Barcaliente Formation type section (NW Spain) are not abundant, but the sedimentary record seems unusually well represented. The first occurrence of Declinognathodus bernesgae occurs more than 140 m below the first occurrence of Dinaequalis, the taxon of the D. noduliferus species group appearing in the bed of the Global Standard Stratotype‐section and Point (GSSP) for the Mid‐Carboniferous Boundary (Arrow Canyon, Nevada). P1 elements transitional between D. bernesgae and Dinaequalis are described and considered relevant to the global correlation of the Mid‐Carboniferous Boundary. In addition, D. praenoduliferus, D. cf. noduliferus, D. lateralis, Idiognathoides asiaticus, I. corrugatus and Neognathodus sp. are described and illustrated from the Barcaliente Formation. A phylogeny is proposed for the early species of these genera on the basis of the morphological changes of the P1 element, where the rostral parapet and area, the surface roughness and the length and depth of the adcarinal troughs are diagnostic characters at the specific level, while caudal ornamentation is a secondary taxonomic character.  相似文献   

13.
聂拉木是西藏南部志留纪含笔石地层(石器坡组)的主要产地。近期在该地亚来村新发现一批笔石标本,包括Normalograptus sp.、Glyptograptus sp.、Campograptus lobiferus、C. cf. lobiferus、C. cf. obtusus、C.? circularis、Lituigraptus cf.convolutus、Rastrites cf.perfectus、Stimulograptussedgwickii、Streptograptus sp.和Torquigraptus decipiens。该组合面貌确定其属于志留系兰多维列统埃隆阶上部Lituigraptusconvolutus带至Stimulograptus sedgwickii带。这一新材料的发现,使西藏南部的志留纪地层得以作全球对比。  相似文献   

14.
The fossil fauna of the Santana Formation (Early Cretaceous) comprises many distinct taxa, but crocodylomorphs are poorly understood. Here we describe a new specimen (MPSC-R1137) that consists of a complete hind limb found in the Crato Member, the basal section of the Santana Formation. Based on the characteristics of the fibula (e.g., pronounced variation of the shaft width) and length proportions of the femur and tibia, this specimen can be distinguished from Caririsuchus camposi and Araripesuchus gomesii, which are known from the Romualdo Member (the upper lithostratigraphic unit of the Santana Formation). The only crocodylomorph formally described from the Crato Member is Susisuchus anatoceps, whose holotype lacks elements of the hind limb. On the basis of a comparative anatomical study of the hind limb, which shows no similarities between MPSC-R1137 and other crocodylomorphs from the Araripe Basin, we tentatively classify this new specimen as cf. Susisuchus sp., and provide new anatomical information for this rather derived crocodylomorph.   相似文献   

15.
Abstract: A systematic account of highly diverse cyrtocrinid faunules from Upper Jurassic strata of ?tramberk type (Oxfordian–Tithonian) in southern Poland (Polish Carpathians) is presented. Fourteen taxa (Phyllocrinus malbosianus, Ph. stellaris, Ph. sp., Psalidocrinus armatus, Sclerocrinus compressus, Spolonicus sp. nov., Hemicrinus aff. kabanovi, Ancepsicrinus parvus gen. et sp. nov., Tetracrinus baumilleri sp. nov., Eugeniacrinites alexandrowiczi, E. cf. moravicus, E. sp., Eudesicrinus gluchowskii sp. nov. and Hemibrachiocrinus tithonicus sp. nov. are described and illustrated. Representatives of the genus Eudesicrinus, previously recorded only from the Lower Jurassic, are here shown to extend into the uppermost Jurassic. Other cyrtocrinids considered are common in Jurassic/Cretaceous strata across Europe. In the present faunules, isocrinid (Isocrinida), comatulid (Comatulida) and roveacrinid (Roveacrinida sensu Rasmussen, inclusive of Saccocoma) crinoids are associated.  相似文献   

16.
Thirty-four seed morphometric and colorimetric features of the five taxa belonging to the Lavatera triloba aggregate were measured using an image analysis system. Data were statistically analysed using a Linear Discriminant Analysis (LDA), which provided evidence to reassess the taxonomic position of some neglected or doubtful taxa. The results confirm the differentiation of the insular endemics L. agrigentina, L. triloba ssp. pallescens and L. triloba ssp. minoricensis. Moreover, the Sardinian populations of L. triloba ssp. triloba are clearly differentiated from their Iberian counterparts, but on the other hand, the seed morpho-colorimetric variation between L. triloba ssp. triloba and L. flava is not easy to interpret.  相似文献   

17.
New palm leaves from the Oligocene Ningming Formation are placed into the morphogenus Sabalites because of their costapalmate leaf shape. Four taxa are described on the basis of leaf compressions with cuticular structure. S. guanxiensis sp. nov. is characterised by hypostomatic leaf blades with a stout costa and a symmetrical base. Sabalites cf. asymmetricus has amphistomatic leaf blades with a long, delicate costa and an asymmetrical base. Sabalites sp. 1 has amphistomatic leaf blades with a long, massive costa and wide segments. Sabalites sp. 2 is characterized by hypostomatic leaf blades with a prominent costa and an asymmetrical base. The four new palm taxa expand our understanding of the floristic elements and features of the Oligocene Ningming flora. Together with the other three palm taxa that were previously reported from the Ningming Formation, our material indicates that the Oligocene Ningming flora had a rich diversity of costapalmate palms. The relatively high species diversity of palms and other plants corroborate that the Oligocene Ningming flora represents a warm and humid climate.  相似文献   

18.
The biodiversity of peritrich ciliates from brackish biotopes is rarely investigated, especially members of the genus Pseudovorticella. Here, the morphology of three species of Pseudovorticella, i.e. P. cf. vestita (Stokes, 1883) Jankowski, 1976, P. spathulata sp. n., and P. qinghaiensis sp. n. isolated from brackish waters were studied. Pseudovorticella cf. vestita is characterized by inverted bell‐shaped cell; a J‐shaped macronucleus; a single contractile vacuole ventrally located; P3 three‐rowed; pellicle striated with highly developed pellicular vesicles; 18–22 transverse silverlines between peristome and aboral trochal band, and 9–13 between aboral trochal band and scopula. Pseudovorticella spathulata sp. n. differs from its congeners by the following combination of characters: elongate‐elliptical cell; a single contractile vacuole near ventral wall of infundibulum; a J‐shaped macronucleus; P3 three‐rowed; 24–34 silverlines between oral area and aboral trochal band and 6–10 between aboral trochal band and scopula. Pseudovorticella qinghaiensis sp. n. is characterized by: cell with an oval outline; a single contractile vacuole near ventral wall of infundibulum; a C‐shaped macronucleus; P3 three‐rowed; 30–35 and 9–11 transverse silverlines above and below the trochal band, respectively. The SSU rDNA sequences of five Pseudovorticella species, namely P. annulata, P. monilata, P. parakenti, P. spathulata sp. n., and P. cf. vestita, plus that of Zoothamnium hartwigi, are reported for the first time and their evolutionary relationships are investigated. Five undefined Pseudovorticella forms are considered might be conspecific with P. monilata. Two congeners are conspecific with P. spathulata sp. n. Phylogenetic analyses based on SSU rDNA sequences reveal that Pseudovorticella is not monophyletic and Z. hartwigi clusters with its congeners as expected.  相似文献   

19.
An uppermost Permian-Lower Triassic biota of brachiopods, conodonts, algae and foraminifers from the Pamucak and Kokarkuyu formations at Çürük Da? (Antalya, Turkey) is here described. The brachiopods belong to two different assemblages: a lower assemblage, early Wuchiapingian in age, with Spinomarginifera cf. S. helica, Spinomarginifera cf. S. iranica, Alatorthotetina sp. ind., Orthothetina sp. ind., Ombonia antalyensis nov. sp. and few specimens of Pennospiriferinoidea; an upper assemblage, Changhsingian in age, comprising S. cf. S. iranica, Spinomarginifera cf. S. spinosocostata, Spinomarginifera sp. ind. and Orthothetina sp. ind., characteristic taxa of the low diversity survival brachiopod faunas of latest Permian age (Survival Fauna 1). The occurrence of the conodont Hindeodus cf. praeparvus above the brachiopod fauna confirms its Changhsingian age. The oolitic grainstones at the top of the Pamucak Formation contain Permocalculus sp., Macroporella cf. apachena, species of Hemigordius and Palaeozoic Lagenida. Coarse calcite fibrous cements pervade the oo-bioclastic grainstones, suggesting early marine cementation. The base of the Kokarkuyu Formation is characterized by the disaster forms Earlandia amplimuralis and “Cornuspira” mahajeri, gastropods and ostracods. The conodont Isarcicella lobata has been recovered 31 m above the base of the Kokarkuyu Formation, indicating the occurrence of the second Triassic conodont zone above the parvus biozone and below the staeschei biozone. The faunal content at the transition of the Pamucak and Kokarkuyu formations records the biotic survival in the aftermath of the end-Permian extinction. Facies evolution from lower energy inner platform wackestones and packstones to higher energy open platform oolitic grainstones indicates a transgression at the top of the Pamucak Formation, which continues into the Lower Triassic Kokarkuyu Formation.  相似文献   

20.
The first Sinopa species, S. jilinia sp. nov., from outside of North America is described. It comes from the Huadian Formation, locality Gonglangtou, Jilin Province, north‐east China. The new species represents the northernmost and one of the latest and most complete Asian Prototomus‐like hyaenodontidans known. It also represents one of the youngest specimens of Sinopa, because the age of the Huadian Formation is correlated to the later Uintan and only one doubtful citation of North American Sinopa younger than the early Uintan exists. S. jilinia sp. nov. is characterized by having m3 clearly smaller than m1, very strong and extended labial molar cingulids, backward leaning protoconids in all molars and its m3 cristid obliquum joining the postvallid very labially. With S. jilina, Sinopa is the first hyaenodontidan genus known to be present on two continents during the time interval between the earliest Eocene (c. 55.0 Ma) and latest middle Eocene (40 Ma). Its occurrence in the Huadian Formation supports the idea of a faunal exchange between North America and Asia in the early middle Eocene, a hypothesis formerly based mainly on the presence of the omomyid primate Asiomomys in the Huadian Formation, on a small radiation of East Asian trogosine tillodonts and on a couple of perissodactyl genera shared between the middle Eocene of North America and the Irdinmanhan of East Asia. As with the new Sinopa species, these Asian taxa had their closest relatives in North America.  相似文献   

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