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 15 毫秒
1.
2.
《Comptes Rendus Palevol》2008,7(4):211-216
A new leaf-mimicking katydid (Orthoptera: Tettigoniidae: Pseudophyllinae), Archepseudophylla fossilis gen. et sp. nov. is described based on tegmina from the Early Oligocene of France. Lithymnetes laurenti Théobald, 1937 from the Late Eocene of France is transferred to Archepseudophylla comb. nov. The enigmatic ‘Poekillopteramelanospila Cockerell, 1921 from the Early Oligocene of the Isle of Wight (UK) is transferred to Archepseudophylla comb. nov. The present discoveries in the Palaeogene of the Isle of Wight, Céreste, and Marseilles Basins represent the first fossil records of Pseudophyllinae. In addition, these records support warm and humid forest conditions near the palaeolakes of the Isle of Wight, Camoins-les-Bains, and Céreste.  相似文献   

3.
The taxonomy of marsupials from the late Paleogene of North America (Chadronian to Arikareean North American land mammal ages: late Eocene–late Oligocene) is reviewed based on new and previously undescribed fossil material as well as reevaluation of previously described material. Two families are recognized, the Herpetotheriidae and Peradectidae. Nine species of herpetotheriids are recognized within two genera: Herpetotherium Cope, 1873a and Copedelphys Korth, 1994, including one new species, H. tabrumi. The greatest diversity of herpetotheriids was in the Chadronian (four species). By the late Arikareean, only a single species is recognized. The range of Copedelphys is extended into the early Whitneyan (previously limited to Chadronian–Orellan). Among species of Herpetotherium, the ranges of two species have been extended: H. valens (Lambe, 1908) from the Chadronian is reported from the Orellan, and H. marsupium (Troxell, 1923) from the Uintan and Duchesnean is reported from the early Chadronian. The range of H. merriami (Stock and Furlong, 1922), previously only known from the Arikareean of Oregon, is expanded geographically eastward to Montana. Within the Peradectidae only three species are recognized: Peradectes cf. californicus (Stock, 1936) and Didelphidectes pumilis Hough, 1961 from the Chadronian, and Nanodelphys hunti (Cope, 1873b) from the Orellan to early Arikareean. Specimens previously identified as an unnamed new species of Nanodelphys from the Whitneyan and Arikareean are referred here to N. hunti.  相似文献   

4.
Understanding the global climate change from greenhouse to icehouse conditions at the Eocene–Oligocene Transition (EOT) 34 million years ago requires climatic records from oceanic as well as continental realms of the key Late Eocene “doubthouse” period preceding this switch. Here, we report integrated stratigraphic results from well-dated Late Eocene continental mudflat to saline lake paleoenvironments of the Xining Basin (northeastern Tibetan Plateau, western China) recording regional and global change. Cyclostratigraphic analysis strongly suggests continuous dominance of the 41-kyr obliquity cycle in the whole late Eocene interval down to the base of polarity chron C18n.2n at 39 Ma with additional input of the ~ 100-kyr eccentricity cycle up to the base of chron C13r at ~ 34.7 Ma. This might imply that high-latitude climates dominated the area long before the EOT, probably related to incipient ice-volume fluctuations. Furthermore, our results reveal two paleoenvironmental deterioration steps preceding the Eocene–Oligocene Transition. The first step occurs in the top of chron C17n.1n at ~ 36.6 Ma. This age closely corresponds to (1) the high-altitude pollen appearance in chron C16.2r at ~ 36.4 Ma in the same section, (2) the recently dated final retreat of the Tarim Sea in western China, and (3) a shift from precession to obliquity dominance in the Atlantic Ocean. This near co-occurrence suggests global change at this time. We hypothesize this change is related to an increase in incipient ice sheet volume leading to passing threshold conditions for the high-altitude pollen appearance and Tarim Sea retreat, finally leading to decreased moisture availability in the Xining Basin. At the second step, in the base of chron C13r at ~ 34.7 Ma, a substantial increase in clastic sedimentation rates is observed. This might relate to increased climate variability preceding the greenhouse to icehouse transition at the EOT that prevented landscapes to attain equilibrium configurations.  相似文献   

5.
The diversity of the freshwater-fish genus Rasbora (Cyprinidae) on Sri Lanka (five species) is high compared with the four species reported from the peninsula of India, from which the island's cyprinid fauna is derived. The paucity of characters by which species of Rasbora can be phenotypically distinguished renders field identification difficult, adversely affecting the estimation of populations and distributions, with consequences for conservation and management, increasing also the risk of taxonomic inflation. From a sampling of 90 sites across Sri Lanka and based on phylogenetic and haplotype analyses of sequences of cox1 and cytb mitochondrial, and rag1 and irbp nuclear markers, we review the species diversity and phylogeography of Rasbora on the island. Molecular analyses recover, in addition to the five species previously reported, a new (cryptic) species: Rasbora adisi sp. nov. Uncorrected pairwise cox1 genetic distances between species range from 2.0 to 12.3 percent. The Sri Lankan diversification derives from a common ancestor which arrived from India during a sea-level low-stand in the mid-Miocene (15.1 Ma [95% HPD: 11.5–19.8 Ma]), when the present-day island was subaerially connected to the Indian subcontinent by a broad isthmus. This gave rise to a clade comprising five species—R. adisi sp. nov.,Rasbora armitagei, Rasbora microcephalus, Rasbora naggsi and Rasbora wilpita—with a crown age of 9.9 Ma (95% HPD: 7.1–13.3 Ma) and to a clade comprising Indian and Sri Lankan populations of Rasbora dandia, which themselves are reciprocally monophyletic. Morphological analysis of 334 specimens discriminates between most species which, however, are most reliably diagnosed by chromatic characters. The four endemic species exhibit a pattern of inter-basin dispersal via headwater capture, followed by vicariance, explaining the high diversity of the genus on the island.  相似文献   

6.
The genus Hoplitis (Megachilidae: Osmiini) comprises about 360 described species and occurs on all continents except Australia, South America, and Antarctica. Using five genes, we inferred the phylogeny of Hoplitis including 23 out of the 27 currently recognized subgenera, applying both Bayesian and maximum likelihood methods. Compared to the current morphology‐based classification, our phylogeny resulted in three classificatory changes: first, the subgenera Alcidamea, Cyrtosmia, Dasyosmia, Megalosmia, Monumetha, and Prionohoplitis are merged into one large subgenus Alcidamea Cresson, 1864, comb. nov. ; second, the subgenera Annosmia, Bytinskia, Coloplitis, and Hoplitis are merged into one large subgenus Hoplitis Klug, 1807, comb. nov. ; third, the subgenera Acrosmia, Hoplitina, Penteriades, and Proteriades are merged into one large subgenus Proteriades Titus, 1904, comb. nov. We provide evidence that the genus Hoplitis has a Palaearctic origin and that colonization events to southern Africa and to the Nearctic, as well as recolonization events from the Nearctic to the Palaearctic occurred. The species of the genus Hoplitis exhibit an extraordinary diversity in nesting behaviour, comprising both below and above ground nesting. Parsimony mapping revealed that ground nesting in excavated burrows is the ancestral state amongst Hoplitis bees. We hypothesize that nesting biology strongly affected both range expansion and long‐distance dispersal in Hoplitis. © 2012 The Linnean Society of London  相似文献   

7.
The evolution of sexually dimorphic traits has been the focus of much theoretical work, but empirical approaches to this topic have not been equally prolific. Males of the neotropical family Gonyleptidae usually present a strong fourth pair of legs armed with spines, but their functional significance is unknown. We investigated the putative functions of the leg armature in the harvestman Neosadocus maximus. Being a non-visual species, the spines on male legs can only be perceived by females through physical contact. Thus, we could expect females to touch the armature on the legs of their mates if they were to evaluate it. However, we found no support for this hypothesis. We did show that (1) leg armature is used as a weapon in contests between males and (2) spines and associated sensilla are sexually dimorphic structures involved in "nipping behavior", during which a winner emerged in most fights. Finally, we demonstrate that five body structures directly involved in male-male fights show positive allometry in males, presenting slopes higher than 1, whereas the same structures show either no or negative allometry in the case of females. In conclusion, leg armature in male harvestmen is clearly used as a device in intrasexual contests.  相似文献   

8.
The ultrastructure of spermatozoa is a widely accepted source of characters for phylogenetic studies. In this study the fine structure of sperm cells of representatives of six different New and Old World families (Ammotrechidae, Daesiidae, Eremobatidae, Galeodidae, Karschiidae, Solpugidae) of solifuges (Arachnida, Solifugae) were investigated in order to reveal putative characters suitable for subsequent systematic and phylogenetic analyses. The spermatozoa of solifuges represent a relatively simple type of sperm cells. In general, their spermatozoa are roundish, oval shaped (Ammotrechidae, Daesiidae, Eremobatidae, Solpugidae) or plate-shaped (Karschiidae) with or without membrane protuberances and devoid of a flagellum. Only in Galeodidae, very conspicuous thin and elongated sperm cells occur. The spermatozoa either occur as single cells (Eremobatidae, Solpugidae) or in groups of loose knit cells (Ammotrechidae) or in highly ordered groups (Karschiidae). In contrast to the other families studied here, within the Galeodidae and in the genus Blossia (Daesiidae) sperm cells surrounded by a secretion sheath, clearly representing coenospermia, could be observed.  相似文献   

9.
The Eocene–Oligocene transition (EOT) climatic turnover is modelled in the Ebro Basin using CLAMP and analysing the Sarral (Priabonian) and the Cervera (Rupelian) floras. The results show a drop of temperature and an increase in seasonality and precipitation. The changes in temperature and seasonality follow the trend described for the EOT in southern Europe; however, the increase in precipitation is the opposite of what would be expected. This increase might be related to the stratigraphic location of the Sarral Priabonian leaf bed within a dry stage of a precession cycle, whereas the Cervera Rupelian leaf bed would be located within the wet stage of a similar cycle. CLAMP combined with sedimentology, taphonomy and palaeoecology reveals that precession cycles would produce a shift in the habitat of certain plants during the EOT, with the Lauraceae being limited to riparian communities during the Priabonian of Sarral to grow in small laurisilvas during the Rupelian of Cervera.  相似文献   

10.
The eichhorni group lies within the genus Delias (Lepidoptera: Pieridae) which has markedly diversified aposematic wing markings. The phylogenetic relationships among all species of the eichhorni group, representatives of each of the other 21 species groups of Delias butterflies, and some related genera were analyzed based on nucleotide sequences of the mitochondrial NADH dehydrogenase subunit 5 gene. A supplemental study using the nuclear elongation factor-1alpha (EF-1alpha) gene was also carried out. The results are compared with those of morphological studies. Our results confirm the monophyly of the eichhorni group and suggest the monophyly of the genus Delias. They also indicate phylogenetic intragroup relationships, particularly the division of the eichhorni complex into groups I and II. Moreover, they also indicate that the initial diversification of the eichhorni group involved separation of the D. catisa + D. toxopei clade, followed by the divergence of other species including the eichhorni complex. Based on these findings, it is supposed that this group first appeared close to or within the western mountain range of New Guinea Island (135 degrees 30(')-140 degrees E) where D. catisa, D. toxopei, and representatives of other species cohabit.  相似文献   

11.
12.
Using sequence analyses of fragments of the small and large subunits of mitochondrial genes 12S and 16S rRNA, we studied the molecular identity of five Triops populations from the Baja California Peninsula, México. Additionally, we explored the phylogeny of the genus by comparing with sequence data from gonochoric T. longicaudatus (Zacatecas, México), commercial Triops kit (U.S.A.), T. `granarius' (Japan), T. cancriformis (Austria), T. australiensis (Australia) and Lepidurus lemmoni (U.S.A.). The 16S fragment was not useful to discriminate the American Triops forms because their sequences were more than 99% similar. Molecular and phylogenetic analyses using the 12S gene fragments, in agreement with previous allozyme studies, indicate that the nominal (morphological) species T. longicaudatus is a mixture of several species such that, of the seven Triops American populations studied, six phylogenetic species can be identified and two morphologically and reproductively highly divergent forms can be grouped into a single monophyletic clade. The molecular data, rather than supporting our previous proposal that the phylogenetic relationships of Triops species could be deduced by similarities in the number of total and legless rings, suggest that T. cancriformis may represent an independent group from the rest of the species in that genus. In spite of detectable differences among American populations, our analyses indicate these represent a single monophyletic group when compared to Triops from outside of the New World.  相似文献   

13.
Journal of Plant Research - Although many fossil and molecular data suggest migrations from Malesia and Asia to Australia appear to dominate floristic exchange between Australian and Asian...  相似文献   

14.
A new fossil penguin skeleton from the La Meseta Formation collected at the locality DPV 13/84 (Seymour Island, Antarctic Peninsula) from the crinoid horizon located 40 m above the base of the 145 m-thick Submeseta Allomember (Late Eocene–Early Oligocene?) is described. The specimen is assigned to the species Palaeeudyptes klekowskii Myrcha, Tatur and del Valle, 1990; it is the most complete penguin skeleton ever recovered from Antarctica. Discoveries like this one are significant for the study of the anatomy and evolution of penguins, in particular regarding the Antarctic species included in the genus Palaeeudyptes Huxley, 1859. P. klekowskii closely resembles its smaller congeneric species P. gunnari ( Wiman, 1905), with only the relative concavity of the margo medialis distinguishing the tarsometatarsi of both taxa. However, the results of a geometric morphometric analysis show some intra- and inter-specific variations, making possible the systematic assignment of the majority of the specimens. Size variation is congruent with the presence of two different species.  相似文献   

15.
The family Iravadiidae is found to be polyphyletic in a molecular phylogenetic analysis using a subset of Australian taxa. Taxa previously assigned to Iravadia form a monophyletic clade, but Nozeba topaziaca clusters with Auricorona queenslandica n. gen. and n. sp. in an unnamed family related to Tornidae. Aenigmula criscionei n. gen. and n. sp., an iravadiid-like species from the Northern Territory, belongs to another unnamed family related to Caecidae, Calopiidae and Clenchiellidae. A systematic revision of some Australian ‘iravadiids’ raises the subgenera Fluviocingula and Pseudomerelina to full generic rank and reinstates two former synonyms of Iravadia (Fairbankia), Pellamora and Wakauraia, as genera. The species formerly identified in Australia as Iravadia quadrasi is recognised as three allopatric species; Iravadia pilbara n. sp. and the reinstated species Iravadia goliath and Iravadia quadrina. Pellamora splendida n. sp., from Western Australia, is recognised as distinct from Pellamora australis, and Fluviocingula superficialis n. sp. from Fluviocingula resima. Wakauraia fukudai n. sp. is recorded from central Queensland.

http://zoobank.org/urn:lsid:zoobank.org:pub:1B9917F6-48B2-4597-85C1-F90BA9093475  相似文献   


16.
17.
The cause of discrepancies in the literature regarding the specificity of immobilized Candida antarctica lipase B in the acylation of oligosaccharides was examined. Molecular sieves, generally used to control the water content during acylation reactions, turned out to have an important role in this. It was proven that molecular sieves alone can catalyze the acylation of fructose oligomers using vinyl laurate, leading to multiple substitution of the oligomers. This effect was the most profound at conditions unfavorable for the enzyme, because this resulted in a relatively high concentration of the chemically produced adducts. The enzyme alone catalyzed the formation of monosubstituted oligomers. It was proven that even solvent pre-drying by molecular sieves already causes the release of catalyzing compounds to the liquid, leading to subsequent catalysis. These findings should be taken into account when applying molecular sieves in this type of reactions in the future. Molecular sieves could, moreover, be used as a catalyst when multiple substitution is desired.  相似文献   

18.
The carditid genus Cyclocardia is currently the most diverse genus of the family, including nearly 180 nominal species encompassing wide stratigraphical (Cretaceous–Recent) and geographical (Antarctica, South and North America, Europe, Africa, Alaska, Russia, Japan and New Zealand) ranges. Due to the lack of autapomorphies in the diagnosis of the genus and its large account of species, we re-evaluate the systematic and phylogenetic status of Cyclocardia. We applied three approaches: bibliographic revision, phylogenetic analysis and an exploration of morphological disparity. We used a shell–character matrix comprising 65 taxa (2 outgroups, 29 non-Cyclocardia carditids and 28 species of Cyclocardia) for phylogenetic and disparity analyses. Maximum Observable Rescaled Distances was used to construct a distance matrix to compare Cyclocardia species and other carditid groups. According to our results, Cyclocardia represents a non-monophyletic taxon and is thus a ‘wastebasket taxon’, chiefly because its diagnosis was based mainly on plesiomorphic characters. The European species C. kickxi and C. chameformis are placed within Scalaricardita, and the previously proposed genus Crassicardia is monophyletic (including C. crassidens, C. crebricostata, C. isaotakii and C. rjabininae). Three new genera are proposed for new groups identified by the phylogenetic analysis: South American Oesterheldia gen. nov. (including O. cannada and O. dalek), western North American Coanicardita gen. nov. (including C. ventricosa and C. occidentalis), and North Pacific Hippocampocardia gen. nov. (including H. barbarensis, H. hamiltonensis and H. yakatagensis). The newly defined monophyletic Cyclocardia is restricted to the Atlantic Ocean species C. borealis, C. novangliae and C. compressa.  相似文献   

19.
The wing louse genus Lunaceps, is the most speciose chewing louse (Phthiraptera) genus inhabiting sandpipers (Charadriiformes: Calidrinae) and is known from almost all sandpiper species. The hosts follow specific flyways from the Arctic breeding grounds to wintering locations in the southern hemisphere, and often form large mixed-species flocks during migration and wintering. We estimated a phylogeny of Lunaceps based on three mitochondrial loci, supporting monophyly of the genus but revealing extensive paraphyly at the species level. We also evaluated the relative importance of flyway differentiation (same host species having different lice along different flyways) and flyway homogenisation (different host species having the same lice along the same flyway). We found that while the lice of smaller sandpipers and stints show some evidence of flyway homogenisation, those of larger sandpipers do not. No investigated host species migrating along more than one flyway showed any evidence of flyway differentiation. The host-parasite associations within Lunaceps are in no case monophyletic, rejecting strict cospeciation.  相似文献   

20.
Fossil scorpions are among the oldest terrestrial arthropods known from the fossil record. They have a worldwide distribution and a rich fossil record, especially for the Paleozoic. Fossil scorpions from Mesozoic and Cenozoic deposits are usually rare (except in amber-deposits). Here, we describe the only fossil scorpion from the Early to Middle Eocene Pesciara Lagerstätte in Italy. Eoeuscorpius ceratoi gen. et sp. nov. is probably a genus and species within the family Euscorpiidae. This may be the first fossil record of the Euscorpiidae, which are so far only known from four extant genera. Eoeuscorpius ceratoi gen. et sp. nov. was found in the “Lower Part” of the Pesciara Limestone, which is actually dated Late Ypresian stage (between 49.5 and 49.7 Ma). Besides a possible pseudoscorpion, the here-described fossil scorpion is the second arachnid species known from the Bolca Locality.  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