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.
A new species of fossil Tubulidentata has been found by the Mission Paléoanthropologique Franco-Tchadienne in Northern Chad. It is the first fossil Orycteropodidae (aardvark) from the Mio-Pliocene of Central Africa. The new taxon, Orycteropus abundulafus sp. nov. , is considered in the framework of the available Orycteropodidae fossil record. The Chadian specimen is characterized by the highest dental robustness index among all Tubulidentata, the presence of crests on the pterygoid, the triangular-shaped olecranon fossa and the reduction of the deltoid crest. All of these characters are linked to a less fossorial animal that had a tougher diet. This new African species is closer to the Eurasian O. gaudryi than to any other Tubulidentata. Together they form a clade distinct from that which includes O. afer . This is the first evidence of a relationship for aardvarks between Africa and Eurasia. An initial step is made towards revision of the phylogeny of the order.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 143 , 109–131.  相似文献   

2.
Species in the genus Bothrops s. l. are extraordinarily variable in ecology and geography, compared with other genera in the subfamily Crotalinae. In contrast to the trend of splitting large and variable groups into smaller, more ecologically and phenotypically cohesive genera, the genus Bothrops has remained speciose. In addition, previous phylogenetic analyses have found Bothrops to be paraphyletic with respect to the genus Bothriopsis. Taxonomic arguments exist for synonymizing Bothriopsis with Bothrops, and for splitting Bothrops into smaller genera, but the greatest hindrance to taxonomic revision has been incomplete phylogenetic information. We present a phylogeny of Bothrops, Bothriopsis, and Bothrocophias based on 85 characters of morphology and 2343 bp of four mitochondrial gene regions, and with significantly greater taxonomic coverage than previous studies. The combined data provide improved support over independent datasets, and support the existence of discrete species groups within Bothrops. The monophyly and distinctness of these groups warrant recognition at the generic level, and we propose a new taxonomic arrangement to reflect these findings. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 617–640.  相似文献   

3.
The phylogeny and taxonomy of the whole family Hippopotamidae is in need of reconsideration, the present confusion obstructing palaeoecology and palaeobiogeography studies of these Neogene mammals. The revision of the Hippopotamidae initiated here deals with the last 8 Myr of African and Asian species. The first thorough cladistic analysis of the family is presented here. The outcome of this analysis, including 37 morphological characters coded for 15 extant and fossil taxa, as well as non-coded features of mandibular morphology, was used to reconstruct broad outlines of hippo phylogeny. Distinct lineages within the paraphyletic genus Hexaprotodon are recognized and characterized. In order to harmonize taxonomy and phylogeny, two new genera are created. The genus name Choeropsis is re-validated for the extant Liberian hippo. The nomen Hexaprotodon is restricted to the fossil lineage mostly known in Asia, but also including at least one African species. The genus Hippopotamus is confirmed. These changes represent substantial advances for understanding the evolutionary history of the Hippopotamidae, and provide a new framework for future studies.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society , 2005, 143 , 1–26.  相似文献   

4.
5.
The family Galatheidae is among the most diverse families of anomuran decapod crustaceans, and the South‐West Pacific is a biodiversity hot spot for these squat lobsters. Attempts to clarify the taxonomic and evolutionary relationships of the Galatheidae on the basis of morphological and molecular data have revealed the existence of several cryptic species, differentiated only by subtle morphological characters. Despite these efforts, however, relationships among genera are poorly understood, and the family is in need of a detailed systematic review. In this study, we assess material collected in different surveys conducted in the Solomon Islands, as well as comparative material from the Fiji Islands, by examining both the morphology of the specimens and two mitochondrial markers (cytochrome oxidase subunit I, COI, and 16S rRNA). These two sources of data revealed the existence of eight new species of squat lobster, four of which were ascribed to the genus Munida, two to the genus Paramunida, one to the genus Plesionida, and the last species was ascribed to the genus Agononida. These eight species are described along with phylogenetic relationships at the genus level. Our findings support the taxonomic status of the new species, yet the phylogenetic relationships are not yet fully resolved. Further molecular analysis of a larger data set of species, and more conserved genes, will help clarify the systematics of this group. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 465–493.  相似文献   

6.
7.
Systematics of the genera of Bodotriidae (Crustacea: Cumacea)   总被引:1,自引:1,他引:0  
The cumacean family Bodotriidae includes 382 species in 31 genera grouped in three subfamilies: Bodotriinae, Mancocumatinae and Vaunthompsoniinae. Generic diagnoses are based on few characters that often have overlapping states among genera, complicating the understanding of the relationships within the group. The goals of this study are to illuminate the phylogenetic relationships among the genera of the Bodotriidae using morphological characters and to review the systematics of the family. For this purpose, all species within each genus were studied from the literature to code all the variability of genera for 109 variable morphological characters. Phylogenetic analyses show that there is independent reduction of the pleopods in two clades from a plesiomorphic state of five pairs, while the number of exopods of peraeopods has been reduced gradually in more derived groups of bodotriids. The subfamily Bodotriinae is the most derived and the Vaunthompsoniinae the most basal, and is paraphyletic with the Mancocumatinae embedded within it. No discriminatory characters were found between the subfamilies Mancocumatinae and Vaunthompsoniinae and they are not clearly separated in the phylogeny. Mancocumatinae is synonymized with Vaunthompsoniinae and all the genera of the former Mancocumatinae should be included within Vaunthompsoniinae. Analyses of character evolution justify a few other taxonomic changes. All genera were redescribed based on all the coded characters and a complete list of all valid species for each genus is included. Finally, dichotomous keys for identification to genus level are provided.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 151 , 1–58.  相似文献   

8.
This paper describes a new genus and species of shrew from the Pleistocene (levels 4, 5, and 6) of the Gran Dolina site, located in the Sierra de Atapuerca (Burgos, Spain). Dolinasorex glyphodon gen. et sp. nov. (Mammalia, Soricidae) is a type of large‐sized soricine, endemic in character, which inhabited the Sierra de Atapuerca in the last part of the Early Pleistocene (c. 780–900 kya). Morphometric and phylogenetic analyses indicate that the new species is more closely related to Asiatic forms than to the species Beremendia fissidens with its primarily European distribution. The main palaeoecological and palaeobiogeographical implications of the new taxon in the area around Atapuerca and in the Iberian Peninsula in general are discussed. The paper also presents a tentative phylogeny for the Soricinae subfamily in Eurasia, including for the first time exclusively fossil species, producing results that may prove to be of great interest for more complete studies in the future. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 904–925.  相似文献   

9.
The taxonomic history of the diatom genus Amphora is one of a broad early morphological concept resulting in the inclusion of a diversity of taxa, followed by an extended period of revision and refinement. The introduction of molecular systematics has increased the pace of revision and has largely resolved the relationships between the major lineages, indicating homoplasy in the evolution of amphoroid symmetry. Within the two largest monophyletic lineages, the genus Halamphora and the now taxonomically refined genus Amphora, the intrageneric morphological and ecological relationships have yet to be explored within a phylogenetic framework. Critical among this is whether the range of morphological features exhibited within these diverse genera are reflective of evolutionary groupings or, as with many previously studied amphoroid features, are nonhomologous when examined phylogenetically. Presented here is a four‐marker molecular phylogeny that includes 31 taxa from the genus Amphora and 77 taxa from the genus Halamphora collected from fresh, brackish, and salt waters from coastal and inland habitats of the United States and Japan. These phylogenies illustrate complex patterns in the evolution of frustule morphology and ecology within the genera and the implications of this on the taxonomy, classification, and organization of the genera are discussed.  相似文献   

10.
Apple snails (Ampullariidae) are a diverse family of pantropical freshwater snails and an important evolutionary link to the common ancestor of the largest group of living gastropods, the Caenogastropoda. A clear understanding of relationships within the Ampullariidae, and identification of their sister taxon, is therefore important for interpreting gastropod evolution in general. Unfortunately, the overall pattern has been clouded by confused systematics within the family and equivocal results regarding the family's sister group relationships. To clarify the relationships among ampullariid genera and to evaluate the influence of including or excluding possible sister taxa, we used data from five genes, three nuclear and two mitochondrial, from representatives of all nine extant ampullariid genera, and species of Viviparidae, Cyclophoridae, and Campanilidae, to reconstruct the phylogeny of apple snails, and determine their affinities to these possible sister groups. The results obtained indicate that the Old and New World ampullariids are reciprocally monophyletic with probable Gondwanan origins. All four Old World genera, Afropomus, Saulea, Pila, and Lanistes, were recovered as monophyletic, but only Asolene, Felipponea, and Pomella were monophyletic among the five New World genera, with Marisa paraphyletic and Pomacea polyphyletic. Estimates of divergence times among New World taxa suggest that diversification began shortly after the separation of Africa and South America and has probably been influenced by hydrogeological events over the last 90 Myr. The sister group of the Ampullariidae remains unresolved, but analyses omitting certain outgroup taxa suggest the need for dense taxonomic sampling to increase phylogenetic accuracy within the ingroup. The results obtained also indicate that defining the sister group of the Ampullariidae and clarifying relationships among basal caenogastropods will require increased taxon sampling within these four families, and synthesis of both morphological and molecular data. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 61–76.  相似文献   

11.
Thum  Ryan A. 《Hydrobiologia》2004,519(1-3):135-141
The phylogenetic relationships among the numerous genera of diaptomid copepods remain elusive due to difficulties in obtaining sufficient numbers of phylogenetically informative morphological characters for cladistic analysis. Molecular phylogenetic techniques offer high potential to resolve phylogenetic relationships in the absence of sufficient morphological characters because of the ease in which many characters can be unambiguously coded. I present the first molecular phylogeny for diaptomid copepod genera using 18S rDNA. Specifically, I test Light’s (1939) hypothesis regarding the interrelationships among the North American diaptomid genera. The 18S phylogeny is remarkably consistent with Light’s hypothesis. The endemic North American genera represent a monophyletic group exclusive of the non-endemic genera. Moreover, his hypothesized basal genus for the North America genera, Hesperodiaptomus, is the basal genus in this analysis. However, his Leptodiaptomus group is not reciprocally monophyletic with his Hesperodiaptomus group, but is rather a derived member of the latter group. Finally, the genus Mastigodiaptomus is found to be more closely allied with the non-endemic genera, as Light suggested. This phylogeny contributes heavily to the understanding of phylogenetic relationships among North American diaptomids and has large implications for the systematics of diaptomids in general. The use of 18S rDNA sequences in phylogenetic analyses of diaptomid copepods can be used to confirm the monophyly of recognized genera, the interrelationships among genera, and subsequent biogeographic interpretation of the family’s diversification. The use of molecular data, such as 18S rDNA sequences, to test phylogenetic hypotheses based on a very limited number of morphological characters will be a particularly useful approach to phylogenetic analysis in this system.  相似文献   

12.
13.
Eulophiinae comprise c. 270 species divided into nine genera, with the species‐rich terrestrial genus Eulophia representing 60% of this diversity. Remarkable ecological and morphological variation, and an absence of clear diagnostic characters have led to uncertain generic delimitation in the subtribe. Using a combination of new and previously published DNA sequences, we created a dataset representing 122 taxa and all genera of Eulophiinae and inferred a complete generic‐level phylogeny for the subtribe for the first time. Our sampling focused on analysing Afro‐Madagascan taxa and therefore included representatives of the four mostly epiphytic Madagascan endemic genera, the near Madagascan endemic Oeceoclades and additional sampling of the predominantly African genera Eulophia and Orthochilus. In total, 104 new accessions were collected for this study in Zambia and Madagascar (88 of which represented 36 Eulophia spp. and 12 Oeceoclades spp.). Independent plastid and nuclear phylogenetic trees were inferred using Bayesian and maximum‐likelihood algorithms, which recovered strong support for a monophyletic Eulophiinae, the first‐branching position of the mostly epiphytic Madagascan endemic genera, and increased support for recognition of the terrestrial genera Oeceoclades and Orthochilus. Eulophia, the largest genus in the group, was recovered as polyphyletic, but with implications for its classification and that of Geodorum, that was nested in the main Eulophia clade. Although relationships among several genera were resolved with some confidence, the positions of the South African endemic genus Acrolophia and the epiphytic Madagascan endemic Paralophia require further work. Taxon sampling of Asian Eulophia is a priority for future work on the systematics of this group. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 43–56.  相似文献   

14.
Although diurnal birds of prey have historically been placed in a single order due to a number of morphological characters, recent molecular phylogenies have suggested that this is a case of convergence rather than homology, with hawks (Accipitridae) and falcons (Falconidae) forming two distantly related groups within birds. The feather lice of birds have often been used as a model for comparing host and parasite phylogenies, and in some cases there is significant congruence between the two. Thus, studying the phylogeny of the lice of diurnal raptors may be of particular interest with respect to the independent evolution of hawks vs. falcons. Using one mitochondrial gene and three nuclear genes, we inferred a phylogeny for the feather louse genus Degeeriella (which are all obligate raptor ectoparasites) and related genera. This phylogeny indicated that Degeeriella is polyphyletic, with lice from falcons vs. hawks forming two distinct clades. Falcon lice were sister to lice from African woodpeckers, whereas Capraiella, a genus of lice from rollers lice, was embedded within Degeeriella from hawks. This phylogeny showed significant geographical structure, with host geography playing a larger role than host taxonomy in explaining louse phylogeny, particularly within clades of closely related lice. However, the louse phylogeny does reflect host phylogeny at a broad scale; for example, lice from the hawk genus Accipiter form a distinct clade. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 837–847.  相似文献   

15.
16.
The influence of Quarternary glacial cycles on the extant diversity of Holarctic species has been intensively studied. It has been hypothesized that palaeoclimatic changes are responsible for divergence events in lineages. A constant improvement in DNA sequencing and modeling methods, as well as palaeoclimatic reconstruction, permit a deeper exploration of general causes of speciation in geological time. In the present study, we sampled, as exhaustively as possible, the butterflies belonging to the genus Melitaea (Lepidoptera: Nymphalidae), which are widely spread in the Palaearctic region. We conducted analyses to assess the phylogeny of the genus and estimated the timing of divergence and the most likely distribution of ancestral populations. The results obtained indicate that the systematics of the genus is in need of revision and that the diversity of the genus has been profoundly shaped by palaeoenvironmental changes during its evolutionary history. The present study also emphasizes that, when employed with caveats, major palaeoenvironmental events could represent very powerful tools for the calibration of the dating of divergences using molecular data.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 346–361.  相似文献   

17.
We present a near comprehensive, densely sampled, multilocus phylogenetic estimate of species relationships within the anuran family Ceratobatrachidae, a morphologically and ecologically diverse group of frogs from the island archipelagos of Southeast Asia and the South‐West Pacific. Ceratobatrachid frogs consist of three clades: a small clade of enigmatic, primarily high‐elevation, semi‐aquatic Sundaland species currently assigned to Ingerana (for which we erect a new genus), which is the sister taxon of two large, monophyletic radiations, each situated on islands on either side of Wallace's Line. One radiation is composed of Philippine species of Platymantis and the other contains all taxa from the eastern Indonesian, New Guinean, Solomon, Bismarck, and Fijian archipelagos. Several additional genera (Batrachylodes, Discodeles, Ceratobatrachus, and Palmatorappia) are nested within Platymantis, and of these Batrachylodes and Discodeles are nonmonophyletic. To address the widespread paraphyly of the genus Platymantis and several additional nomenclatural issues, we undertook a wholesale nomenclatural reorganization of the family. Given our partially unresolved phylogeny, and in order to impart a conservative, stable taxonomy, involving a minimal number of genus‐species couplet changes, we propose a conservative classification representing a few compromises. These changes are designed to preserve maximally the presumed original intent of taxonomy (widely used group names associated with morphological and ecological diversity of particular species or groups of species) while implementing a hierarchical system that is consistent with the estimate of phylogeny based on new molecular data. © 2015 The Linnean Society of London  相似文献   

18.
Nomenclatural confusion has existed within the Mylodontinae for several genera, and has resulted in the supposition that Paramylodon of North America is synonymous with Glossotherium of South America. A taxonomic revision of crania for Glossotherium and Paramylodon upholds their separation as distinct genera and provides a list of diagnostic characters that have been lacking. Assessment was made using principal components analysis for suites of cranial and mandibular measurements, evaluation of ratios and measurement distribution, and by examining qualitative characters. Results show the greatest characterization for the skull comes from differences relating to cranial length versus width, whereas the mandible is predominantly distinguished by qualitative characters of the predental spout. Examination of the Pliocene species Glossotherium chapadmalense from South America shows a combination of characters indicative of each genus, but exhibits more with Glossotherium and is tentatively retained under that genus. The mix of characters indicates that G. chapadmalense is the likely ancestor to Paramylodon, although when and where the transition took place is still unclear. During the evolutionary transition, Paramylodon crania emphasized an increase in length of the palate, whereas those of Glossotherium emphasized an increase in cranial width. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 885–903.  相似文献   

19.
Fishes of the order Alepocephaliformes, slickheads and tubeshoulders, constitute a group of deep‐sea fishes poorly known in respect to most areas of their biology and systematics. Morphological studies have found alepocephaliform fishes to display a mosaic of synapomorphic and symplesiomorphic characters, resulting in great difficulties when attempting to resolve intra‐ and interrelationships. Molecular data recently added to the confusion by removing Alepocephaliformes from the Euteleostei and placed them as incertae sedis within the Otocephala. In the present study we attempt to further clarify relationships of Alepocephaliformes by adding newly determined whole mitogenome sequences from 19 alepocephaliforms in order to address 1) phylogenetic position of Alepocephaliformes within the Otocephala; and 2) intrarelationships of Alepocephaliformes. The present study includes 96 taxa of which 30 are alepocephaliforms and unambiguously aligned sequences were subjected to partitioned maximum likelihood and Bayesian analyses. Results from the present study support Alepocephaliformes as a genetically distinct otocephalan order as sister clade to Ostariophysi (mostly freshwater fishes comprising Gonorynchiformes, Cypriniformes, Characiformes, Siluriformes and Gymnotiformes). The disputed family Bathylaconidae was found to be an artificial assemblage of the two genera Bathylaco and Herwigia, with the former as the sister group of the family Alepocephalidae and the latter nested within Alepocephalidae. Platytroctidae was found to be monophyletic as sister clade to the rest of Alepocephaliformes. Previously unrecognized clades within the family Alepocephalidae are presented and a clade comprising Alepocephalus, Conocara and Leptoderma was recovered as the most derived. As long as the current classification is being followed, the genera Alepocephalus, Bathytroctes, Conocara and Narcetes were all found non‐monophyletic. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 923–936.  相似文献   

20.
Following taxonomic revisions in recent years, the originally large family Grapsidae MacLeay, 1838 has become a relatively small and morphologically homogeneous family in terms of adult and larval morphology. Most available molecular studies including more than one genus of the family have also suggested monophyly of the corresponding taxa. However, no single phylogenetic study has ever included all constituent genera of the Grapsidae. In the current study, a molecular phylogeny based on sequences of the mitochondrial 16S rRNA gene from all eight grapsid genera and 34 species is presented and suggests that up to four genera are not monophyletic. This is mainly due to the polyphyletic nature of the genus Pachygrapsus which can be found in six different lineages of the phylogeny, suggesting that the genus currently does not represent a single evolutionary lineage and is in need of taxonomic revision. Amphi-atlantic and trans-isthmian species pairs or populations in four genera are compared and reveal relatively constant and pronounced divergences across the Panama Isthmus as opposed to moderate divergences across the Atlantic Ocean, thereby suggesting occurrence of gene flow across the Atlantic Ocean during the past three million years.  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