首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
A new genus and species of tapiromorph, Skopaiolophus burmese nov. gen., nov. sp., is described from the middle Eocene Pondaung Formation in central Myanmar. This small form displays a striking selenolophodont morphology associated with a mixture of primitive “condylarthran” dental characters and derived tapiromorph features. Skopaiolophus is here tentatively referred to a group of Asian tapiromorphs unknown so far. The occurrence of such a form in Pondaung suggests that primitive tapiromorphs might have persisted in southeast Asia until the late middle Eocene while they became extinct elsewhere in both Eurasia and North America.  相似文献   

3.
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   

4.
Ferinestrix vorax is an extinct mustelid carnivoran of enigmatic relationships, known from a partial mandible and femur collected from the 3.2‐ and 3.6‐Myr‐old deposits of Hagerman Fossil Beds National Monument, Idaho, USA. Here, we report Ferinestrix rapax sp. nov. based on 80 remains of skull and dentition from a 3.1–3.6‐Myr‐old deposit of Udunga, Transbaikal, Russia. We demonstrate that Ferinestrix is a stem genus of the badger subfamily Melinae. This genus is distinctly larger and more carnivorous than any other total‐clade meline. We show that Ferinestrix originated in Asia and immigrated to North America no later than at the early (Zanclean) to late (Piacenzian) Pliocene transition, and that the North American F. vorax and Asian F. rapax underwent parallel evolution toward increased carnivory. © 2013 The Linnean Society of London, Zoological Journal of the Linnean Society, 2013, 167 , 208–226.  相似文献   

5.
Eupatorium were examined by sequencing the internal transcribed spacers (ITS) of nuclear ribosomal DNA and restriction site analysis of chloroplast DNA. Molecular data provided strong evidence that (1) this genus originated in North America, (2) the genus diverged into three morphological species groups, Eutrochium, Traganthes and Uncasia in North America, and (3) one of the North American Uncasia lineages migrated into temperate Europe and eastern Asia over the Bering land bridge. The estimated divergence times support a late Miocene to early Pliocene migration from North America to Eurasia via the Bering land bridge. A European species was sister to all of the eastern Asian species examined. The disjunct distribution pattern of the genus Eupatorium is incongruent with the classical Arcto-Tertiary geoflora concept. Received 13 September 1999/ Accepted in revised form 4 January 2000  相似文献   

6.
A new genus, Asiaontsira gen. nov., and two new species, A. cucphuongi sp. nov. (type species) and A. cantonica sp. nov., are described from tropical and subtropical areas of South‐East China and North Vietnam. This genus is compared to the closely related Australian Ontsirospathius Belokobylskij, Iqbal and Austin, 2004 as well as the similar and almost cosmopolitan genus Ontsira Cameron, 1900. A key to both species of Asiaontsira gen. nov. is provided.  相似文献   

7.
Morphological and DNA data show that effused representatives of the Auriculariales (Basidiomycota) with sphaeropedunculate basidia belong to eleven genera of which seven are dealt with in this study. Among them, Myxarium is the largest genus containing 21 accepted species of which nine are reintroduced below and five are described as new. Protodontia is limited to three species only, P. subgelatinosa (the generic type) and two newly described species from Africa. Protoacia is a new monotypic genus for P. delicata, sp. nov., widely distributed on coniferous hosts in Eurasia. Myxariellum is erected for two new species with smooth hymenophore from northwestern North America while Gelacantha is introduced for G. pura, a new species with hydnoid hymenophore from Caucasus. Our data do not confirm the present synonymy of Sebacina sphaerospora with Tremella glaira, and these species are placed in two separate genera – Hydrophana, gen. nov., and Ofella, gen. nov., respectively. A key to European Myxarium and similar‐looking species is included.  相似文献   

8.
A cladistic analysis of the species of Nipponoserica Nomura, 1972, was executed using 36 morphological characters of adults. From the generated phylogenetic tree, the monophyly of the genus is supported, when Pseudosericania Kobayashi, 1980 is included. Consequently, Pseudosericania Kobayashi, 1980 is considered a junior subjective synonym of Nipponoserica Nomura, 1972. Interestingly, the analysis indicates the monophyly of the East Asian Nipponoserica and the North American Stilbolemma. A new genus, Xenoserica gen. nov., is established for the basal monophyletic clade found for the Himalayan species so far assigned to Nipponoserica including the first brachypterous species of Sericini from the Himalaya. Two new species are described: Xenoserica brachyptera sp. nov. from Nepal, and Nipponoserica dahongshanica sp. nov. from Hubei (China).  相似文献   

9.
A cladistic analysis of the genus Karos Goodnight & Goodnight, 1944, was performed using morphological data of the somatic and male genitalia characters. The analysis included 23 terminal taxa, including nine of the 11 described species of the genus plus nine new species according to the previous generic diagnosis and five species as outgroups. According to the topologies obtained by parsimony analyses, the genus is a paraphyletic assemblage, referred here as the Karos genus‐group. Therefore, the genus Karos is rediagnosed here and now includes seven species: Karos barbarikos Goodnight & Goodnight, 1944 (type), Karos parvus Goodnight & Goodnight, 1971, Karos projectus Goodnight & Goodnight, 1971, K aros hexasetosus sp. nov. , K aros monjarazi sp. nov. , K aros singularis sp. nov. , and K aros tersum sp. nov. The genera Monterella Goodnight & Goodnight, 1944, Montabunus Goodnight & Goodnight, 1945, Chapulobunus Goodnight & Goodnight, 1946, and Potosa Goodnight & Goodnight, 1947 are revalidated, rediagnosed, their respective type species are redescribed and the following species are described: Chapulobunus poblano sp. nov. and Potosa reddelli sp. nov. The genera Crettaros gen. nov. , Huasteca gen. nov. , and Mictlana gen. nov. , and the following species are described: Crettaros santibanezi sp. nov. (type), Crettaros valdezi sp. nov. , and Huasteca silhavyi sp. nov. The following new combinations are proposed: Huasteca gratiosa (Goodnight & Goodnight, 1971) comb. nov. (type), Huasteca rugosa (Goodnight & Goodnight, 1971) comb. nov. and Mictlana inops (Goodnight & Goodnight, 1971) comb. nov. (type). Karos brignolii ?ilhavý, 1974, is considered a junior synonym of Huasteca rugosa. Finally, ‘Karosdepressus Goodnight & Goodnight, 1971 is considered incertae sedis until adult males can be studied. Diagnoses of the Karos and Paramitraceras genus‐groups, and an identification key to the eight genera and 19 species of the former are provided. © 2015 The Linnean Society of London  相似文献   

10.
Hybodontoid and nonhybodontoid sharks are described from the Lower Triassic Vega‐Phroso Siltstone Member of Sulphur Mountain Formation on the basis of newly discovered material. The age of the classic fossil site ‘Wapiti Lake’ in the Canadian Rocky Mountains is discussed on the basis of new field data and one conodont found in association. Preliminary results suggest that these elasmobranch remains are between early Smithian and Spathian in age. Apart from the enigmatic genus Listracanthus and previously reported edestoids, the shark fauna consists of at least one hybodont, at least two questionable hybodontoid genera and an elasmobranch of enigmatic affinities, represented by peculiar denticles only and described as ‘genus A’incertae sedis. The presence of the only previously reported hybodont genus, cf. Palaeobates, is erroneous. The largest specimen represents the most complete Early Mesozoic shark known. The heterodonty of its dentition, fin spine morphology and the short, robust body shape imply it represents a member of a new family of shark, Wapitiodidae fam. nov. , and is described here as Wapitiodus aplopagus gen. et sp. nov. The unique dental morphology shows affinities to Polyacrodus but clearly differs in the complete lack of side cusps. Wapitiodus gen. nov. possesses a primitive fin spine structure. The tooth crowns are entirely blunt in the distal (posterior) tooth files, and are acuminate‐unicuspid in several anterior files. Tooth morphology, the shape of the basal cartilages, the proximal insertion of the fin spines and the pectoral fin structure are interpreted as diagnostic characters for this new genus, and possibly for the Wapitiodidae fam. nov. The majority of observed characters appear to be primitive and are reminiscent of Palaeozoic sharks, however, and these features include dorsal fin spine morphology and gross skull anatomy. A second species, provisionally placed in the same genus, is described as Wapitiodus homalorhizo sp. nov. Wapitiodus homalorhizo sp. nov. can be distinguished from W. aplopagus gen. et sp. nov. by the proportions of the fin spines, tooth morphology and possibly the body shape. Several isolated teeth and other fragmentary material are referred to either Wapitiodus gen. nov. sp. indet. or to ?Polyacrodus sp. (Polyacrodontidae gen. et sp. indet.). A third genus of elasmobranch (incertae sedis) is described as ‘Genus A’ and is recognized by its peculiar scales. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 149 , 309–337.  相似文献   

11.
The fossil record for neoceratopsian (horned) dinosaurs in the Lower Cretaceous of North America primarily comprises isolated teeth and postcrania of limited taxonomic resolution, hampering previous efforts to reconstruct the early evolution of this group in North America. An associated cranium and lower jaw from the Cloverly Formation (?middle–late Albian, between 104 and 109 million years old) of southern Montana is designated as the holotype for Aquilops americanus gen. et sp. nov. Aquilops americanus is distinguished by several autapomorphies, including a strongly hooked rostral bone with a midline boss and an elongate and sharply pointed antorbital fossa. The skull in the only known specimen is comparatively small, measuring 84 mm between the tips of the rostral and jugal. The taxon is interpreted as a basal neoceratopsian closely related to Early Cretaceous Asian taxa, such as Liaoceratops and Auroraceratops. Biogeographically, A. americanus probably originated via a dispersal from Asia into North America; the exact route of this dispersal is ambiguous, although a Beringian rather than European route seems more likely in light of the absence of ceratopsians in the Early Cretaceous of Europe. Other amniote clades show similar biogeographic patterns, supporting an intercontinental migratory event between Asia and North America during the late Early Cretaceous. The temporal and geographic distribution of Upper Cretaceous neoceratopsians (leptoceratopsids and ceratopsoids) suggests at least intermittent connections between North America and Asia through the early Late Cretaceous, likely followed by an interval of isolation and finally reconnection during the latest Cretaceous.  相似文献   

12.
Oxyaenid creodonts are extinct carnivorous mammals known from the Paleogene of North America, Europe, and Asia. The genus Palaeonictis is represented by three species that together span the late Paleocene to early Eocene of North America, and at least one species from the early Eocene of Europe. Previously, only a single trigonid of Palaeonictis was known from the interval encompassing the Paleocene-Eocene Thermal Maximum (PETM) in North America. We describe Palaeonictis wingi sp. nov. from the PETM in the Cabin Fork drainage, southeastern Bighorn Basin, Wyoming, based on associated right and left dentaries with P2-M2. Palaeonictis wingi sp. nov. is substantially smaller than the other North American congeners, making it similar in size to P. gigantea from the earliest Eocene of Europe and the previously described PETM specimen. We suggest that a form similar to the large-bodied late Paleocene P. peloria from North America gave rise to two smaller species in the earliest Eocene of North America (P. wingi) and Europe (P. gigantea). Palaeonictis wingi may have given rise to P. occidentalis following the PETM in North America. Dispersal of Palaeonictis to Europe coincided with rapid global warming of 5–10°C and related geographic range shifts in plants and other animals during the PETM. It has been suggested that certain mammalian lineages decreased in body size during the PETM, possibly in response to elevated temperature and/or higher CO2 levels. Results from a dietary analysis of Palaeonictis indicate that it was an omnivore that primarily consumed meat. This suggests that the decreased nutritious quality of vegetation caused by increased CO2 levels was not the direct contributing factor that caused body size reduction of this lineage during the PETM. Other selective pressures such as temperature, aridity, and prey size may have also contributed to the smaller body size of carnivorous mammals during this interval, although the presence of smaller species could also be explained by latitudinal range shifts of mammals during the PETM.  相似文献   

13.
Cordimus, a new genus of cricetid rodent, is described from Neogene deposits on the islands of Curaçao and Bonaire, Dutch Antilles. The genus is characterized by strongly cuspidate molars, the presence of mesolophs in most upper molars and the absence of mesolophids in lower molars. Similarities with the early cricetid Copemys from the Miocene of North America coupled with apparent derived characters shared with the subfamily Sigmodontinae suggest that Cordimus may be close to the root of the sigmodontine lineage, a possibility that remains to be tested through explicit phylogenetic analysis. Three species are recognized on the basis of size and details of molar morphology. Cordimus hooijeri sp. nov. is described from Bonaire on the basis of Holocene owl pellet material that consists of dentaries and postcranial material only. This species is presumed to be extinct, but focused surveys are needed to confirm this hypothesis. Cordimus debuisonjei sp. nov. and Cordimus raton sp. nov. are described from deposits on Tafelberg Santa Barbara in Curaçao. Although the age of these deposits is not known, they are most likely of late Pliocene or early Pleistocene age. Both are represented by numerous isolated molars and some osteological material.  相似文献   

14.
Phylogenetic analyses of molecular data (COI, 16SrDNA, 18SrDNA, and 28SrDNA) show that the hesionid genus Gyptis Marion & Bobretzky in Marion, 1874, and the tribe Gyptini Pleijel, 1998, are nonmonophyletic as currently delineated. We introduce the new tribe Amphidurini and the new genus Neogyptis to accommodate these new findings. Amphidurini is sister to Gyptini and Ophiodromini and includes Amphiduros Hartman, 1959, Amphiduropsis, Pleijel, 2001, Neogyptis gen. nov. , and, possibly, Parahesione Pettibone, 1956. Morphologically, Amphidurini can be separated from Gyptini by the distally, rather than subdistally, inserted ventral cirri, and Neogyptis by the combination of this feature, the presence of a median antenna, and a distal ring with papillae on the proboscis. We redescribe and transfer the four species Gyptis crypta Pleijel, 1993, Gyptis mediterranea Pleijel, 1993, Gyptis plurisetis Hilbig, 1992, and Gyptis rosea (Malm, 1874) from Gyptis to Neogyptis gen. nov. , and describe five new species from shallow waters in Belize, Hong Kong, off Vladivostok, and deep‐sea hydrothermal vents in the Lau Basin off Fiji.  相似文献   

15.
Abstract: In the early Late Devonian, terminal Frasnian proetid trilobites have previously only been known from Europe and North Africa. For the first time, a rich fauna of late Frasnian proetids is described from the Virgin Hills Formation, Canning Basin, Western Australia. Seventeen species in six genera are described, of which three are new: Rudybole gen. nov., Palpebralina gen. nov. and Canningbole gen. nov. A new subgenus, Chlupaciparia (Australoparia) subgen. nov. is also described. Fourteen of the species are new: Palpebralia initialis sp. nov., P. pustulata sp. nov., ?P. sp. nov. A, Rudybole depressa sp. nov., Palpebralina pseudopalpebralis sp. nov. (comprising the subspecies P. pseudopalpebralis pseudopalpebralis subsp. nov. and P. pseudopalpebralis ultima subsp. nov.), P. minor sp. nov., P. ocellifer sp. nov., Canningbole latimargo sp. nov., C. henwoodorum sp. nov., C. macromma sp. nov., Pteroparia extrema sp. nov., Chlupaciparia (Chlupaciparia) planiops sp. nov., Chlupaciparia (Australoparia) australis sp. nov. and C. (Australoparia) lata sp. nov. The subspecies Rudybole adorfensis angusta subsp. nov. is also described. The proetids range through conodont Zones 11–13b and terminate at the Upper Kellwasser Event, which marks the terminal Frasnian mass extinction event. Three of the six proetid lineages, Palpebralia, Canningbole and Pteroparia, show evolutionary trends of eye reduction. Two of the remaining lineages, Rudybole and Palpebralina, consist exclusively of blind taxa. The last, Chlupaciparia, also comprises forms with reduced eyes. The proetids show a stepped pattern of extinction during the late Frasnian, which correlate with two Kellwasser biocrises documented in European/North African Frasnian sections. The highest diversity preceded the Lower Kellwasser event that occurred at the end of conodont Zone 12 and saw the extinction of all species present in that zone. However, only one genus, Pteroparia, locally became extinct. A major higher‐level taxonomic mass extinction at the top of Zone 13b initiated the Upper Kellwasser extinction event. This included extinction at the generic level, with all five remaining genera becoming extinct, and at the family level, with the loss of the Tropidocoryphidae.  相似文献   

16.
A second basal hadrosauroid dinosaur, Zuoyunlong huangi gen. et sp. nov., is reported from the early Late Cretaceous Zhumapu Formation in Zuoyun County, Shanxi Province, northern China. Zuoyunlong preserves a partial right ilium and ischium and is unique in having a very short postacetabular process 50% as long as the iliac central plate. Our cladistic analysis recovers Zuoyunlong as the most basal Late Cretaceous hadrosauroid, with a sister taxon relationship with Probactrosaurus from the late Early Cretaceous of Inner Mongolia. Including Zuoyunlong, four Cenomanian basal hadrosauroids have been recorded, and the two taxa in North America (Eolambia and Protohadros) represent the earliest known hadrosauroids outside of Asia. In the light of the proposed phylogenetic topology and biogeographic data, the discovery of Zuoyunlong indicates that the first dispersal of hadrosauroids from Asia to North America probably happened around the boundary between the Early and Late Cretaceous.  相似文献   

17.
A new genus of Gliridae, Simplomys gen. nov. is proposed. It contains glirids with a simplified dental pattern from the European Early and Middle Miocene. Simplomys gen. nov. includes several species originally described as Pseudodryomys such as Simplomys simplicidens, Simplomys robustus, Simplomys julii, and Simplomys aljaphi. In addition, a new species, Simplomys meulenorum sp. nov. , is proposed from the Spanish Miocene. The species of this genus share not only a very reduced and simplified dental morphology, but also unique dental proportions that clearly separate them from any other genera of Gliridae. Simplomys gen. nov. is recorded in most of the fossil faunas from the Early and Middle Miocene of the Iberian Peninsula, and shows the maximum diversity in this area during Mammal Neogene Zones MN 3 and MN 4. The genus has been also recorded in other European countries such as France, Germany, and Switzerland, conferring to this very characteristic taxon an important role for biochronological correlations within the European continent. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 622–652.  相似文献   

18.
Nyssa (Nyssaceae, Cornales) represents a classical example of the well‐known eastern Asian–eastern North American floristic disjunction. The genus consists of three species in eastern Asia, four species in eastern North America, and one species in Central America. Species of the genus are ecologically important trees in eastern North American and eastern Asian forests. The distribution of living species and a rich fossil record of the genus make it an excellent model for understanding the origin and evolution of the eastern Asian–eastern North American floristic disjunction. However, despite the small number of species, relationships within the genus have remained unclear and have not been elucidated using a molecular approach. Here, we integrate data from 48 nuclear genes, fossils, morphology, and ecological niche to resolve species relationships, elucidate its biogeographical history, and investigate the evolution of morphology and ecological niches, aiming at a better understanding of the well‐known EA–ENA floristic disjunction. Results showed that the Central American (CAM) Nyssa talamancana was sister to the remaining species, which were divided among three, rapidly diversified subclades. Estimated divergence times and biogeographical history suggested that Nyssa had an ancestral range in Eurasia and western North America in the late Paleocene. The rapid diversification occurred in the early Eocene, followed by multiple dispersals between and within the Erasian and North American continents. The genus experienced two major episodes of extinction in the early Oligocene and end of Neogene, respectively. The Central American N. talamancana represents a relic lineage of the boreotropical flora in the Paleocene/Eocene boundary that once diversified in western North America. The results supported the importance of both the North Atlantic land bridge and the Bering land bridge (BLB) for the Paleogene dispersals of Nyssa and the Neogene dispersals, respectively, as well as the role of Central America as refugia of the Paleogene flora. The total‐evidence‐based dated phylogeny suggested that the pattern of macroevolution of Nyssa coincided with paleoclimatic changes. We found a number of evolutionary changes in morphology (including wood anatomy and leaf traits) and ecological niches (precipitation and temperature) between the EA–ENA disjunct, supporting the ecological selection driving trait evolutions after geographic isolation. We also demonstrated challenges in phylogenomic studies of lineages with rapid diversification histories. The concatenation of gene data can lead to inference of strongly supported relationships incongruent with the species tree. However, conflicts in gene genealogies did not seem to impose a strong effect on divergence time dating in our case. Furthermore, we demonstrated that rapid diversification events may not be recovered in the divergence time dating analysis using BEAST if critical fossil constraints of the relevant nodes are not available. Our study provides an example of complex bidirectional exchanges of plants between Eurasia and North America in the Paleogene, but “out of Asia” migrations in the Neogene, to explain the present disjunct distribution of Nyssa in EA and ENA.  相似文献   

19.
The genus Holcophloeus gen. nov. is here proposed to include Trachyphloeus cruciatus Seidlitz, 1868, and two new species native to North Africa, based on a phylogenetic analysis and an evaluation of the diagnostic characters. The taxonomic position of Holcophloeus in relation to the tribes Trachyphloeini Lacordaire, 1863, and Holcorhinini Desbrochers, 1898, is discussed, and the new genus is attributed to the Holcorhinini. Holcophloeus laurae sp. nov. from south‐eastern Morocco and Holcophloeus weilli sp. nov. from northern Libya are described and illustrated and a key to the species of the new genus is given. The lectotype of Trachyphloeus cruciatus Seidlitz, 1868, is designated. The genus Massimiellus Borovec, 2009, is transferred from Trachyphloeini to Holcorhinini. © 2013 The Linnean Society of London  相似文献   

20.
The bug Gyaclavator kohlsi Wappler, Guilbert, Wedmann et Labandeira, gen. et sp. nov., represents a new extinct genus of lace bugs (Insecta: Heteroptera: Tingidae) occurring in latest early Eocene deposits of the Green River Formation, from the southern Piceance Basin of Northwestern Colorado, in North America. Gyaclavator can be placed within the Tingidae with certainty, perhaps it is sistergroup to Cantacaderinae. If it belongs to Cantacaderinae, it is the first fossil record of this group for North America. Gyaclavator has unique, conspicuous antennae bearing a specialized, highly dilated distiflagellomere, likely important for intra- or intersex reproductive competition and attraction. This character parallels similar antennae in leaf-footed bugs (Coreidae), and probably is associated with a behavioral convergence as well.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号