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1.
Cryptic species have been detected in many groups of organisms and must be assumed to make up a significant portion of global biodiversity. We study geckos of the Ebenavia inunguis complex from Madagascar and surrounding islands and use species delimitation algorithms (GMYC, BOLD, BPP), COI barcode divergence, diagnostic codon indels in the nuclear marker PRLR, diagnostic categorical morphological characters, and significant differences in continuous morphological characters for its taxonomic revision. BPP yielded ≥?10 operational taxonomic units, whereas GMYC (≥?27) and BOLD (26) suggested substantial oversplitting. In consequnce, we resurrect Ebenavia boettgeri Boulenger 1885 and describe Ebenavia tuelinae sp. nov., Ebenavia safari sp. nov., and Ebenavia robusta sp. nov., increasing the number of recognised species in Ebenavia from two to six. Further lineages of Ebenavia retrieved by BPP may warrant species or subspecies status, but further taxonomic conclusions are postponed until more data become available. Finally, we present an identification key to the genus Ebenavia, provide an updated distribution map, and discuss the diagnostic values of computational species delimitation as well as morphological and molecular diagnostic characters.  相似文献   

2.
Borioteiioidea are an enigmatic group of Cretaceous lizards widely distributed in northern continents (Laurasia). Here, we describe the first borioteiioid lizard from Gondwana, represented by a new species of the polyglyphanodontine genus Bicuspidon, B. hogreli sp. nov., from the Cenomanian Kem Kem beds of Morocco. The discovery of Bicuspidon hogreli sp. nov., which is one of the oldest known member of Polyglyphanodontini, challenges previous assumptions on the center of origin and dispersal of the group. In addition, the known distribution of Bicuspidon (Cenomanian of Utah and Morocco, and Santonian–Maastrichtian of eastern Europe) suggests a complex palaeobiogeographical history for the genus. The existence of a terrestrial dispersal route persisting during the whole Early Cretaceous between North America and Africa is hypothesized to explain some similarities observed between the Cenomanian squamate assemblages of these two continents. Alternatively, dispersal between the two landmasses may have occurred by transatlantic rafting. During the Cenomanian–Santonian interval, Bicuspidon colonized the European archipelago probably from North Africa, like many “Eurogondwanan” taxa.  相似文献   

3.
Although Asia is thought to have played a critical role in the basal radiation of Ruminantia, the fossil record of early selenodont artiodactyls remains poorly documented in this region. Dental remains of a new bunoselenodont artiodactyl are described from the late Eocene of Krabi, southern Thailand. This new form, Krabitherium waileki gen. et sp. nov, is tentatively referred to the Tragulidae (Ruminantia) on the basis of several dental features, including a weak Tragulus fold and the presence of a deep groove on the anterior face of the entoconid. Although this new form is suggestive of the enigmatic ?Gelocus gajensis Pilgrim 1912 from the “base of the Gaj” (lower Chitarwata Formation) of the Bugti Hills (Central Pakistan), K. waileki most likely represents an early representative of a relatively bunodont group of tragulids that includes the genus Dorcabune, known from the Miocene of south Asia. This addition to the Eocene record of early ruminants attests to the antiquity of the group in Southeast Asia and lends support to the hypothesis that the Tragulidae represents one of the first offshoots in the evolutionary history of Ruminantia.  相似文献   

4.
A fossil opilioacarid mite (Parasitiformes: Opilioacarida) in Burmese amber is described as ?Opilioacarus groehni sp. nov. This ca. 99 Ma record (Upper Cretaceous: Cenomanian) represents only the third fossil example of this putatively basal mite lineage, the others originating from Eocene Baltic amber (ca. 44–49 Ma). Our new record is not only the oldest record of Opilioacarida, but it is also one of the oldest examples of the entire Parasitiformes clade. The presence of Opilioacarida—potentially Opiloacarus—in the Cretaceous of SE Asia suggests that some modern genus groups were formerly more widely distributed across the northern hemisphere, raising questions about previously suggested Gondwanan origins for these mites.  相似文献   

5.
The fossil record of Late Cretaceous–Paleogene modern birds in the Southern Hemisphere includes the Maastrichtian Neogaeornis wetzeli from Chile, Polarornis gregorii and Vegavis iaai from Antarctica, and Australornis lovei from the Paleogene of New Zealand. The recent finding of a new and nearly complete Vegavis skeleton constitutes the most informative source for anatomical comparisons among Australornis, Polarornis, and Vegavis. The present contribution includes, for the first time, Vegavis, Polarornis, and Australornis in a comprehensive phylogenetic analysis. This analysis resulted in the recognition of these taxa as a clade of basal Anseriformes that we call Vegaviidae. Vegaviids share a combination of characters related to diving adaptations, including compact and thickened cortex of hindlimb bones, femur with anteroposteriorly compressed and bowed shaft, deep and wide popliteal fossa delimited by a medial ridge, tibiotarsus showing notably proximally expanded cnemial crests, expanded fibular crest, anteroposterior compression of the tibial shaft, and a tarsometatarsus with a strong transverse compression of the shaft. Isolated bones coming from the Cretaceous and Paleogene of South America, Antarctica, and New Zealand are also referred to here to Vegaviidae and support the view that these basal anseriforms were abundant and diverse at high southern latitudes. Moreover, vegaviids represent the first avian lineage to have definitely crossed the K–Pg boundary, supporting the idea that some avian clades were not affected by the end Mesozoic mass extinction event, countering previous interpretations. Recognition of Vegaviidae indicates that modern birds were diversified in southern continents by the Cretaceous and reinforces the hypothesis indicating the important role of Gondwana for the evolutionary history of Anseriformes and Neornithes as a whole.  相似文献   

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7.
The objectives of this work are to use gene sequence data to assess the hypothesis that the Lithodinae arose from ancestors with uncalcified abdomens in shallow waters of the North-East Pacific, investigate the monophyly and interrelationships of genera within the Lithodinae and to estimate the scale and minimum number of biogeographic transitions from the shallow environment to the deep sea and vice versa. To do this, phylogenetic analysis from three mitochondrial and three nuclear markers was conducted using minimum evolution, maximum likelihood and Bayesian methods. The Lithodinae as defined to include North Pacific genus Cryptolithodes may be paraphyletic, with the Hapalogastrinae and Cryptolithodes as sister taxa. This implies that the soft-bodied abdomen of the Hapalogastrinae might not be plesiomorphic for the Lithodidae. Paralomis, Lopholithodes, Phyllolithodes, Lithodes and Neolithodes share a common ancestor, from which the North Pacific Hapalogastrinae did not descend. Lithodid ancestors are likely to have had a north Pacific, shallow water distribution and to have had planktotrophic larvae. North Pacific genus Paralithodes is paraphyletic; P. brevipes is the most basal member of the genus (as sampled) while P. camtschaticus and P. platypus are more closely related to the genera Lithodes and Neolithodes. Genera Lithodes, Neolithodes and Paralomis (as sampled) are monophyletic if Glyptolithodes is included within Paralomis. Lopholithodes is closely related to, but not included within, the Paralomis genus. Paralomis is divided into at least two major lineages: one containing South Atlantic, West African, and Indian Ocean species, and the other containing Pacific and South American species. Several species of Paralomis do not resolve consistently with any other groups sampled, implying a complex and possibly rapid global evolution early in the history of the genus. Relationships within the Lithodes genus vary between analytical methods, suggesting that conclusions may not be stable. Consistently, however, Indian Ocean and Pacific forms—L. murrayi, L. longispina and L. nintokuae form a group separated from Atlantic species such as L. santolla, L. confundens, L. maja and L. ferox.  相似文献   

8.
The tuatara (Sphenodon punctatus) from New Zealand is often—erroneously—identified as a ‘living fossil’, although it is the lone survivor of a large, successful radiation of Rhynchocephalia, sister taxon to squamates (lizards and snakes), that thrived through the Mesozoic and Cenozoic and experienced an intricate evolution of life histories and feeding habits. Within Rhynchocephalia, only Pleurosauridae are thought to be marine and piscivorous. Here, we present bone histological data of the Jurassic pleurosaurid Palaeopleurosaurus, showing osteosclerosis (i.e. bone mass increase) in its gastralia, and some osteosclerosis in its rib but no increase in bone mass in the femur, supporting a gradual skeletal specialization for an aquatic way of life. Similar to Sphenodon, the bone tissue deposited in Palaeopleurosaurus is lamellar zonal bone. The femoral growth pattern in Palaeopleurosaurus differs from that of terrestrial Sphenodon in a more irregular spacing of growth marks and deposition of non-annual (i.e. non-continuous) rest lines, indicating strong dependency on exogenous factors. The annual growth mark count in adult but not yet fully grown Palaeopleurosaurus is much lower when compared to adult individuals of Sphenodon, which could indicate a lower lifespan for Palaeopleurosaurus. Whereas the gastral ribs of Palaeopleurosaurus and Sphenodon are similar in composition, the ribs of Sphenodon differ profoundly in being separated into a proximal tubular rib part with a thick cortex, and an elliptical, flared ventral part characterised by extremely thin cortical bone. The latter argues against a previously inferred protective function of the ventral rib parts for the vulnerable viscera in Sphenodon.  相似文献   

9.
The antifungal potential of the pygidial gland secretion of the troglophilic ground beetle Laemostenus punctatus from a cave in Southeastern Serbia against cave-dwelling micromycetes, isolated from the same habitat, has been investigated. Eleven collected samples were analyzed and 32 isolates of cave-dwelling fungi were documented. A total of 14 fungal species were identified as members of the genera Aspergillus, Penicillium, Alternaria, Cladosporium, Rhizopus, Trichoderma, Arthrinium, Aureobasidium, Epicoccum, Talaromyces, and Fusarium. Five isolates were selected for testing the antifungal activity of the pygidial gland secretion: Talaromyces duclauxi, Aspergillus brunneouniseriatus, Penicillium sp., Rhizopus stolonifer, and Trichoderma viride. The microdilution method has been applied to detect minimal inhibitory concentrations (MICs) and minimal fungicidal concentrations (MFCs). The most sensitive isolate was Penicillium sp., while the other isolates demonstrated a high level of resistance to the tested agent. L. punctatus has developed a special mechanism of producing specific compounds that act synergistically within the secretion mixture, which are responsible for the antifungal action against pathogens from the cave. The results open opportunities for further research in the field of ground beetle defense against pathogens, which could have an important application in human medicine, in addition to the environmental impact, primarily.  相似文献   

10.
Toothless pterosaurs played a key role in broadening the taxonomic, morphological and ecological diversity of Cretaceous pterosaurs. Here we report a complete, articulated skeleton of a 1.4-m-wingspan pterosaur from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China which is identified as a new genus and species, Shenzhoupterus chaoyangensis gen. et sp. nov. The new taxon is edentulous, with a relatively large skull and a remarkably large, tall nasoantorbital fenestra that extends well above the main part of the braincase. Phylogenetic analysis shows that Shenzhoupterus gen. nov. belongs in a distinct clade of azhdarchoid pterosaurs, formally recognised here as a new family, Chaoyangopteridae, that also includes Chaoyangopterus, Jidapterus and Eoazhdarcho from the Jiufotang Formation and Eopteranodon from the Yixian Formation. These new data clarify recent confusion surrounding the systematics of these Lower Cretaceous taxa and provide new insights into the evolutionary history of pterosaurs.  相似文献   

11.
Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have involved four wings (Xu et al. Nature 421:335–340, 2003; Hu et al. Nature 461:640–643, 2009; Han et al. Nat Commun 5:4382, 2014). Here, we describe Serikornis sungei gen. et sp. nov., a new feathered theropod from the Tiaojishan Fm (Late Jurassic) of Liaoning Province, China. Its skeletal morphology suggests a ground-dwelling ecology with no flying adaptations. Our phylogenetic analysis places Serikornis, together with other Late Jurassic paravians from China, as a basal paravians, outside the Eumaniraptora clade. The tail of Serikornis is covered proximally by filaments and distally by slender rectrices. Thin symmetrical remiges lacking barbules are attached along its forelimbs and elongate hindlimb feathers extend up to its toes, suggesting that hindlimb remiges evolved in ground-dwelling maniraptorans before being co-opted to an arboreal lifestyle or flight.  相似文献   

12.
The Cretaceous Carcharodontosauridae is the latest clade of carnosaurs, including the largest predatory dinosaurs yet recorded. Albeit spectacular for their size, the skeletal anatomy of these theropods remains poorly-known, and their diversity was until recently restricted to two Cenomanian species: the highly derived Giganotosaurus carolinii, from southern South America, and the incompletely known Carcharodontosaurus saharicus, from northern Africa. Here we describe an older and basal member of the group, Tyrannotitan chubutensis gen. et sp. nov., from Aptian strata of Patagonia, Argentina. The new taxon gives new insights into the systematics and evolution of carcharodontosaurids and offers a better understanding of the evolution of Southern theropod faunas. We suggest that carcharodontosaurids radiated in Gondwana sharing with spinosaurids the role of top-predators until their extinction in Cenomanian–Turonian times. During this interval, the diplodocoid sauropods and giant titanosaurians went extinct (probably as part of a global-scale crisis), and the smaller abelisaurid theropods took dominance, reigning until the end of the Cretaceous. Electronic Supplementary Material is available.Electronic Supplementary Information  Supplementary material is available for this article at  相似文献   

13.
Agustinia ligabuei is an Early Cretaceous sauropod dinosaur from the northwest of Patagonia that is currently the topic of debate with respect to its phylogenetic position and atypical dermal armor. The presence of four morphotypes of laminar and transversely elongated putative osteoderms was used to consider Agustinia as an armored sauropod. Regarding the different hypotheses about the identity of the bony structures of Agustinia (e.g., osteoderms, cervical or dorsal ribs, hypertrophied elements), a comparative histological analysis has been carried out. Histological evidence is presented herein and reveals that none of the morphotypes of Agustinia shows a primary bone tissue formed by structural fiber bundles as in other sauropod dinosaur osteoderms. Furthermore, on the basis of their gross morphology and microstructure, the bony structures originally classified as types 1 + 4 and 3 are more comparable respectively with dorsal and cervical ribs than any other kind of dermal or bony element. Due to poor preservation, the nature of the type 2 cannot be assessed but is here tentatively assigned to a pelvic girdle element. Although a phylogenetic reassessment of Agustinia is not the purpose of this paper, our paleohistological analyses have broader implications: by not supporting the dermal armor hypothesis for Agustinia, its inclusion in Lithostrotia is not justified in the absence of other diagnostic features.  相似文献   

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15.
贵州关岭晚三叠世早期海生爬行动物的初步研究   总被引:9,自引:0,他引:9  
通过初步研究 ,记述了贵州关岭晚三叠世早期瓦窑组中的海生爬行动物 3个目 ,2个亚目 ,6个科(其中 2个新科 ) ,9个属 (其中 6个新属 )和 10个种 (其中 9个新种 )。关岭地区晚三叠世所发现的海生爬行动物是关岭动物群中最重要的组成部分 ,其总体面貌与古特提斯海的海生爬行动物比较相似 ,但关岭地区晚三叠世海生爬行动物群具有三叠纪与侏罗—白垩纪动物群之间的过渡性质 ,在种类的组成上具有明显的地方性和很高的多样性 ,是当今世界绝无仅有的。关岭晚三叠世海生爬行动物的发现 ,对研究海生爬行动物的分类、演化、古生态和古埋藏学都具有重要的科学意义及价值  相似文献   

16.
Although shell colour polymorphism of the land snail Cepaea nemoralis is a well-known phenomenon, proximate and ultimate factors driving its evolution remain uncertain. Polymorphic species show variation in behavioural responses to selective forces. Therefore, we estimated effects of various environmental factors (temperature, humidity, food availability, (micro)habitat structure and predatory pressure) on behavioural response (frequency of locomotion, climbing and hiding) of C. nemoralis morphs, in experimental and natural conditions. In the experimental part of study, the frequency of locomotion was negatively affected by temperature and the presence of food and positively influenced by the presence of light. Morphs significantly differed in behavioural responses to environmental variability. Pink mid-banded and yellow five-banded morphs climbed less often and hide in shelter more often than yellow and pink unbanded individuals when temperature was low and food was absent. Snails fed most often at moderate temperature compared to low and high temperatures. Field investigations partially confirmed differences among morphs in frequency of climbing, but not in terms of probability of hiding in sheltered sites. In natural colonies, temperature and (micro)habitat structure significantly affected frequency of climbing as well as hiding in shelter. Snails more often hid in sheltered sites where thrushes preyed on Cepaea. Tendency of unbanded morphs to climb trees may have evolved under avian predatory pressure as thrushes forage on a ground. Tendency of banded morphs to hide in sheltered sites may reflect prey preferences for cryptic background. The results implicate that differential behaviour of C. nemoralis morphs compensate for their morphological and physiological limitations of adaptation to habitat.  相似文献   

17.
Chinese softshell turtles (Pelodiscus spp.) are widely distributed, ranging from the Amur and Ussuri Rivers in the Russian Far East through the Korean Peninsula, Japan, and eastern, central, and southern China to southern Vietnam. In East and Southeast Asia, Chinese softshell turtles are traditionally exploited for food and have been farm-bred in China since the Spring and Autumn Period, more than 2400 years ago. Currently, the annual production of Pelodiscus amounts to 340,000 t in China alone. Using mitochondrial DNA (2428 bp) and five nuclear loci (3704 bp), we examined broad sampling of wild and farm-bred Pelodiscus to infer genetic and taxonomic differentiation. We discovered four previously unknown mitochondrial lineages, all from China. One lineage from Jiangxi is deeply divergent and sister to the mitochondrial lineage of Pelodiscus axenaria. The nuclear loci supported species status for P. axenaria and the new lineage from Jiangxi. Pelodiscus maackii and P. parviformis, both harboring distinct mitochondrial lineages, were not differentiated from P. sinensis in the studied nuclear markers. The same is true for two new mitochondrial lineages from Zhejiang, China, represented by only one individual each, and another new lineage from Anhui, Guangdong, Jiangxi and Zhejiang, China. However, Vietnamese turtles yielding a mitochondrial lineage clustering within P. sinensis were distinct in nuclear markers, suggesting that these populations could represent another unknown species with introgressed mitochondria. Its species status is also supported by the syntopic occurrence with P. sinensis in northern Vietnam and by morphology. In addition, we confirmed sympatry of P. axenaria and P. parviformis in Guangxi, China, and found evidence for sympatry of P. sinensis and the new putative species from Jiangxi, China. We also discovered evidence for hybridization in turtle farms and for the occurrence of alien lineages in the wild (Zhejiang, China), highlighting the risk of genetic pollution of native stock. In the face of the large-scale breeding of Pelodiscus, we claim that the long-term survival of distinct genetic lineages and species can only be assured when an upscale market segment for pure-bred softshell turtles is established, making the breeding of pure lineages lucrative for turtle farms. Our findings underline that the diversity of Pelodiscus is currently underestimated and threatened by anthropogenic admixture. We recommend mass screening of genetic and morphological variation of Chinese softshell turtles as a first step to understand and preserve their diversity.  相似文献   

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Small terrestrial non-eusuchian mesoeucrocodylians are common components of Cretaceous assemblages of Gondwanan provinces with notosuchians and araripesuchids as flagship taxa in South America, Africa and Madagascar, well into the Late Cretaceous. On the other hand, these are exceedingly rare in Laurasian landmasses during the Late Cretaceous. Small terrestrial mesoeucrocodylians from Europe were often referred to the genus Theriosuchus, a taxon with stratigraphic range extending from the Late Jurassic to the late Early Cretaceous. Theriosuchus is abundantly reported from various European localities, although Asiatic and possibly North American members are also known. It has often been closely associated with the first modern crocodilians, members of the Eusuchia, because of the presence of procoelous vertebrae, a widespread key character diagnosing the Eusuchia. Nevertheless, the relationships of Theriosuchus have not been explored in detail although one species, Theriosuchus pusillus, has been extensively described and referred in numerous works. Here, we describe a new basal mesoeucrocodylian, Theriosuchus sympiestodon sp. nov. from the Maastrichtian of the Haţeg Basin, Romania, suggesting a large temporal gap (about 58 myr) in the fossil record of the genus. Inclusion of the new taxon, along with Theriosuchus guimarotae, in a phylogenetic analysis confirms its referral to the genus Theriosuchus, within a monophyletic atoposaurid clade. Although phylogenetic resolution within this clade is still poor, the new taxon appears, on morphological grounds, to be most closely related to T. pusillus. The relationships of Atoposauridae within Mesoeucrocodylia and especially to Neosuchia are discussed in light of the results of the present contribution as well as from recent work. Our results raise the possibility that Atoposauridae might not be regarded as a derived neosuchian clade anymore, although further investigation of the neosuchian interrelationships is needed. Reports of isolated teeth referable to a closely related taxon from the Upper Cretaceous of Romania and France, together with the presence of Doratodon and Ischyrochampsa, indicate a previously unsuspected diverse assemblage of non-eusuchian mesoeucrocodylians in the Late Cretaceous European archipelago.  相似文献   

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