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1.
External characters, hemipenial morphology, karyotype, and reproductive mode were examined for the three subspecies of the endemic Ryukyu natricine, Amphiesma pryeri . Results revealed that populations of the Yaeyama Group, currently regarded as comprising a subspecies, A. p. ishigakiense , have several unique features such as the brownish ground colour of head, termination of sulcus spermaticus in the crotch between apical lobes of the hemipenis, terminal location of centromeres in the largest microchromosome pair, and the viviparous mode of reproduction. In the other populations, ground colour of head is black or dark greyish tan; sulcus spermaticus terminates near the tip of the left lobe of the hemipenis; the largest microchromosome pair is metacentric; and the reproductive mode is oviparous. Of these, however, the Miyakojima population, which currendy consists solely of the subspecies, A. p. concelarum , differs from the nominotypical subspecies from the central Ryukyus in having only 94–102 subcaudal scales and telocentric W chromosome; A. p. pryeri has 112–130 subcaudal scales and submetacentric W chromosomes. These strongly suggest that the two subspecies have also substantially diverged from each other, constituting distinct evolutionary lineages. We thus accord full-species status to each of pryeri, concelarum and ishigakiense , and revise their definitions on the basis of the present results. A dichotomous key to the Japanese species and subspecies of Amphiesma is provided.  相似文献   

2.
Sequences of the SINE family specific to squamate reptiles have been isolated from the genomes of lacertid lizards and sequenced. These retroposons, which we called Squam1, are 360–390 bp long and contain a region similar to the tRNA gene sequence at the 5’ end. This family has also been detected in representatives of other reptile families (varanids, iguanids (Anolis), gekkonids, and snakes), being absent from the genomes of crocodiles as well as amphibians, birds, and mammals. The primary structures of Squam1 copies have been comprehensively analyzed and compared with GenBank sequences. The genomes of most taxa contain two to three SINE subfamilies with specific diagnostic features in their primary structures. Individual similarity between the copies within each taxon is about 85%, with intrageneric similarity being only slightly higher. A comparison of consensus sequences between different lizard families has shown that Squam1 may be a convenient phylogenetic marker for this group of reptiles, having a number of both apomorphic and more or less pronounced synapomorphic features. By this criterion, snakes slightly differ from lizards but obviously belong to the same clade. However, they show no special affinity to varanids as the putative closest relatives of snakes, compared to other lizards.  相似文献   

3.
The Guiana Shield harbours one of the best preserved and largest extents of tropical forest on Earth and an immense biodiversity. The herpetofauna of this region remains poorly known. The species-rich snake genus Atractus contains ~140 species, many with complicated taxonomic histories, including A. schach. Examination of specimens in museums and newly collected material from French Guiana has allowed the illustration of hemipenial morphology for the first time and an expanded diagnosis. Concatenated molecular phylogenetic (mitochondrial and nuclear genes) and phenotypic (morphometrics, external and hemipenial morphology) analyses confirm non-monophyly of the A. flammigerus group and indicate that A. schach is a species complex with three new species described here. The geographic distribution of A. schach sensu stricto is restricted to Guiana, Surinam, and French Guiana north of Tumucumaque massif. Populations tentatively assigned to A. schach from the east from French Guiana in the Roura lowlands to Almeirim, and from central Amazonia between the Negro and Trombetas rivers in Brazil are also recognized as new species. Our results suggest that populations from south of the Amazon River are not conspecific with those from the Guiana Shield.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:A7AE40BC-4716-4302-B3BE-1F43600B0A72  相似文献   


4.
5.
The phylogenetic structure of Asclepiadoideae (Apocynaceae) has been elucidated at the tribal and subtribal levels in the last two decades. However, to date, the systematic positions of seven Asian genera, Cosmostigma, Graphistemma, Holostemma, Pentasachme, Raphistemma, Seshagiria and Treutlera, have not been investigated. In this study, we examine the evolutionary relationships among these seven small enigmatic Asian genera and clarify their positions in Asclepiadoideae, using a combination of plastid sequences of rbcL, rps16, trnL and trnL‐ F regions. Cosmostigma and Treutlera are resolved as members of the non‐Hoya clade of Marsdenieae with strong support (maximum parsimony bootstrap support value BSMP = 96, maximum likelihood bootstrap support value BSML = 98, Bayesian‐inferred posterior probability PP = 1.0). Pentasachme is resolved as sister of Stapeliinae to Ceropegieae with moderate support (BSMP = 64, BSML = 66, PP = 0.94). Graphistemma, Holostemma, Raphistemma and Seshagiria are all nested in the Asclepiadeae–Cynanchinae clade (BSMP = 97, BSML = 100, PP = 1.0). The study confirms the generally accepted tribal and subtribal structure of the subfamily. One exception is Eustegia minuta, which is placed here as sister to all Asclepiadeae (BSMP = 58, BSML = 76, PP = 0.99) and not as sister to the Marsdenieae + Ceropegieae clade. The weak support and conflicting position indicate the need for a placement of Eustegia as an independent tribe. In Asclepiadeae, a sister group position of Cynanchinae to the Asclepiadinae + Tylophorinae clade is favoured (BSMP = 84, BSML = 88, PP = 1.0), whereas Schizostephanus is retrieved as unresolved. Oxystelma appears as an early‐branching member of Asclepiadinae with weak support (BSMP = 52, BSML = 74, PP = 0.69). Calciphila and Solenostemma are also associated with Asclepiadinae with weak support (BSMP = 37, BSML = 45, PP = 0.79), but all alternative positions are essentially without support. The position of Indian Asclepiadoideae in the family phylogeny is discussed. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 601–619.  相似文献   

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7.
We conducted a comprehensive analysis of the phylogenetic, phylogeographic, and demographic relationships of Caspian cobra (Naja oxiana; Eichwald, 1831) populations based on a concatenated dataset of two mtDNA genes (cyt b and ND4) across the species'' range in Iran, Afghanistan, and Turkmenistan, along with other members of Asian cobras (i.e., subgenus Naja Laurenti, 1768). Our results robustly supported that the Asiatic Naja are monophyletic, as previously suggested by other studies. Furthermore, Nkaouthia and N. sagittifera were recovered as sister taxa to each other, and in turn sister clades to N. oxiana. Our results also highlighted the existence of a single major evolutionary lineage for populations of N. oxiana in the Trans‐Caspian region, suggesting a rapid expansion of this cobra from eastern to western Asia, coupled with a rapid range expansion from east of Iran toward the northeast. However, across the Iranian range of N. oxiana, subdivision of populations was not supported, and thus, a single evolutionary significant unit is proposed for inclusion in future conservation plans in this region.  相似文献   

8.
Taxonomy of the little‐studied brown algal species Punctaria mageshimensis (Ectocarpales s.l.) was reexamined by molecular phylogeny and morphology. In the genetic analyses of newly collected specimens using plastid rbcL and psaA gene sequences, the specimens morphologically referable to P. mageshimensis were phylogenetically distant from Ectocarpales s.l. and were included in the clade of Spatoglossum (Dictyotales). Morphological reexamination of the type specimen and newly collected specimens confirmed its systematic position in Dictyotales: Branched thallus; cushion‐shaped rhizoidal holdfast occasionally forming secondary holdfast at the bottom of the thallus; many discoidal plastids without pyrenoid per cell; tetrasporangium‐like reproductive structures with dark, homogeneous cell content; occurrence of hair tufts. Genetically P. mageshimensis was most related to a reported sequence of Spatoglossum asperum, but P. mageshimensis was considerably different from S. asperum as well as other known Spatoglossum species in the deep habitat and in having scarcely‐branched lanceolate and considerably thickened thallus. In conclusion, we propose the transfer of P. mageshimensis to Spatoglossum as S. mageshimense comb. nov.  相似文献   

9.
The skull osteology of Hierophis viridiflavus is here described and figured in detail on the basis of 18 specimens. The sample includes specimens from the ranges of both H. viridiflavus viridiflavus and H. viridiflavus carbonarius as well as specimens not identified at sub-specific level. The main characters that define H. viridiflavus in comparison to the parapatric congeneric species Hierophis gemonensis are wide maxillary diastema, basioccipital crest well distinct in three lobes and basioccipital process well marked. The foramina of the otoccipital and prootic, and the basioccipital process of the basioccipital are among the most ontogenetically variable characters, as indicated by two juvenile specimens included in the sample. A specimen-level phylogenetic analysis including H. gemonensis and other outgroups (overall 6 species, 26 specimens, 64 skull characters) recovered all H. viridiflavus specimens in one clade, indicating the presence of a clear phylogenetic signal in the applied characters. However, the resolution within the H. viridiflavus clade is poor the monophyly of H. viridiflavus carbonarius was retrieved, but not that of Hierophis v. viridiflavus. Probably due to the relatively high variability, the skull morphology does not support the recently proposed specific status of the two subspecies.  相似文献   

10.
D. Qi    S. Guo    J. Tang    X. Zhao  § J. Liu  § 《Journal of fish biology》2007,70(SA):60-74
The complete mitochondrial DNA (mtDNA) cytochrome b gene (1140 bp) was sequenced in Herzenstein macrocephalus and Gymnocypris namensis and in 13 other species and sub-species ( n = 22), representing four closely related genera in the subfamily Schizothoracinae. Conflicting taxonomies of H. macrocephalus and G. namensis have been proposed because of the character instability among individuals. Parsimony, maximum likelihood and Bayesian methods produced phylogenetic trees with the same topology and resolved several distinctive clades. Previous taxonomic treatments, which variously placed these two species of separate genera or as sub-species, are inconsistent with the mtDNA phylogeny. Both H. macrocephalus and G. namensis appear in a well-supported clade, which also includes nine species of Schizopygopsis , and hence should be transferred to the genus Schizopygopsis . Morphological changes are further illustrated, and their adaptive evolution in response to the local habitat shifts during the speciation process appears to be responsible for conflicting views on the systematics of these two species and hence the contrasting taxonomic treatments. These species are endemic to the Qinghai-Tibetan Plateau, a region with a history of geological activity and a rich diversity of habitats that may have result in the parallel and reversal evolution of some morphological characters used in their taxonomies. Our results further suggest that speciation and morphological evolution of fishes in this region may be more complex than those previously expected.  相似文献   

11.
The genus Glyphochloa (Poaceae: Panicoideae: Andropogoneae: Rottboellinae) is endemic to peninsular India and is distributed on lateritic plateaus of low and high altitude in and around Western Ghats and the Malabar Coast. The genus presumably originated and diversified in the Western Ghats. Species relationships in the genus Glyphochloa were deduced here based on molecular phylogenies inferred using nuclear ribosomal ITS sequences and plastid intergenic spacer regions (atpB-rbcL, trnT-trnL, trnL-trnF), and new observations were made of spikelet morphology, caryopsis morphology and meiotic chromosome counts. We observed two distinct clades of Glyphochloa s.l. One of these (‘group I’) includes Ophiuros bombaiensis, and is characterized by a single-awned lower glume and a base chromosome number of 6; it grows in low elevation coastal areas. The other clade (‘group II’) has a double-awned lower glume, a base chromosome number of 7, and is restricted to higher elevation lateritic plateaus; G. ratnagirica may belong to the group II clade, or may be a third distinct lineage in the genus. A sister-group relationship between group I and II taxa (with or without G. ratnagirica) is not well supported, although the genus is recovered as monophyletic in shortest trees inferred using ITS or concatenated plastid data. We present a key to species of Glyphochloa and make a new combination for O. bombaiensis.  相似文献   

12.
The land snail superfamily Orthalicoidea, although generally assumed to be of Gondwanan origin, is considered by the majority of recent authors to be absent from the African continent. However, two poorly-known African genera, Aillya and Prestonella , have historically been referred to the orthalicoid family Bulimulidae s.l. Anatomical study of Aillya has subsequently shown it to be morphologically distinct from the Bulimulidae and referable to a family of its own, outside the Orthalicoidea, but Prestonella has remained an enigmatic taxon of unknown affinity. Using molecular and morphological evidence, we demonstrate conclusively that Prestonella is indeed a member of the Bulimulidae s.l. We thus confirm that this family is represented in Africa, and that it has a classical disjunct, tri-continental southern distribution. Thus, either the origin of the family must at the least predate the separation of Africa and South America in the Mid Cretaceous (under a vicariance scenario) or there must have been subsequent dispersal between the isolated Gondwanan fragments. In view of the limited dispersal ability of terrestrial snails, we consider the former more likely. Anatomically, Prestonella exhibits many character states thought to be plesiomorphic, suggesting a relationship with the subfamily Bulimulinae. Bayesian analysis of nuclear DNA sequence data places it as sister group (posterior probability = 1.0) to an Australasian clade comprising Bothriembryon and Placostylus . However, taxon sampling within the Orthalicoidea is currently inadequate to permit meaningful resolution of subfamilial affinity using molecular data. Similarly, although those orthalicoid taxa for which molecular data are available comprise a well-supported clade, the relationships of this clade to other stylommatophoran clades remain unresolved.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 203–221.  相似文献   

13.
Squamate reptiles (lizards and snakes) are one of the most diverse groups of terrestrial vertebrates. Recent molecular analyses have suggested a very different squamate phylogeny relative to morphological hypotheses, but many aspects remain uncertain from molecular data. Here, we analyse higher-level squamate phylogeny with a molecular dataset of unprecedented size, including 161 squamate species for up to 44 nuclear genes each (33 717 base pairs), using both concatenated and species-tree methods for the first time. Our results strongly resolve most squamate relationships and reveal some surprising results. In contrast to most other recent studies, we find that dibamids and gekkotans are together the sister group to all other squamates. Remarkably, we find that the distinctive scolecophidians (blind snakes) are paraphyletic with respect to other snakes, suggesting that snakes were primitively burrowers and subsequently re-invaded surface habitats. Finally, we find that some clades remain poorly supported, despite our extensive data. Our analyses show that weakly supported clades are associated with relatively short branches for which individual genes often show conflicting relationships. These latter results have important implications for all studies that attempt to resolve phylogenies with large-scale phylogenomic datasets.  相似文献   

14.
Within the squamate clade Anguimorpha, Xenosaurus is an enigmatic taxon combining several apparently primitive features with a highly specialized set of autapomorphies. This combination makes the fossil record along the Xenosaurus stem particularly important for resolving the relationships of Xenosaurus with other anguimorphs, and between species of Xenosaurus.Exostinus serratus Cope, 1873 from the Oligocene of the western United States is currently hypothesized to be the immediate sister taxon to Xenosaurus. The cranial osteology of this pivotal taxon is described here for the first time from all known material, using high‐resolution X‐ray computerized tomography (CT) scanning to visualize individual elements. Exostinus serratus displays a mosaic of ancestral anguimorph features that are transformed in Xenosaurus, as well as unique synapomorphies shared with Xenosaurus. The region of the external nares is less transformed than in Xenosaurus, as are the general proportions of the bones surrounding the cartilaginous nasal capsule. However, the forms of the teeth and of the osteodermal sculpture, as well as several details of maxillary and mandibular morphology, are distinctly Xenosaurus‐like. Several autapomorphies are also present, including an abbreviated tooth row and an unusually wide palatal shelf of the maxilla. An understanding of the ways in which the non‐ossified tissues of the head influenced the development of the bones is crucial to interpreting their morphology. Furthermore, subtle anatomical features often provide important comparative information, and are emphasized herein. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 921–953.  相似文献   

15.
Most Neotropical colubrid snakes belong to a single, well‐supported lineage. Relationships between the major constituents of this clade remain. Here, we explore the phylogenetic relationships of Mastigodryas and its affinities to other Neotropical colubrid genera by combining DNA and morphological data. Analyses demonstrate that the concatenation of multiple individuals into a single terminal can mask the detection of new taxa. Further, non‐random missing data and/or taxa in some empirical datasets can bias species tree analyses more than concatenation approaches. Our results place Mastigodryas in a strongly supported clade that includes Drymarchon, Rhinobothryum, Drymoluber, Simophis and Leptodrymus. Mastigodryas bifossatus is more closely related to species of Drymoluber and Simophis than to its congeners. Thus, we erect a new genus to accommodate it and recover a monophyletic Mastigodryas. We highlight the importance of the use of morphological characters to diagnose suprageneric clades by showing that some key external and hemipenial characteristics are phylogenetically informative.  相似文献   

16.
Noncoding regions from the genes encoding aromatase cytochrome P450 and lactoferrin have been sequenced in ten bovine and one cervid species for an investigation of the evolutionary relationships within the tribe Bovini. The evolutionary rate of DNA-nucleotide alterations along the ancestral bovine lineage amounts to 0.38% per million years, as estimated from this combined 0.478-kb-single copy nuclear (scn) DNA sequence data set. Whereas rate homogenity is apparent within the Bovini, the relative rate test suggests that the boselaphine lineage (as represented by Boselaphus) has evolved at only about one third of the rate found within the Bovini. Consistent with other results, the scnDNA data provide evidence for (i) a monophyletic origin of the Bovini, (ii) a sister group position of the Boselaphini, and (iii) two different clades within the Bovini, the buffaloes (Bubalus and Syncerus) and the cattle (Bos/Bibos and Bison). Surprisingly, the results indicate very clearly that the enigmatic dwarf buffalo of Sulawesi Island (Anoa depressicornis) is most closely related to Boselaphus and that the divergence from the true Bovini occurred close to the base of bovine cladogenesis in the Middle Miocene (≈ 14—12 million years ago).  相似文献   

17.
Gobekko cretacicus, a Cretaceous lizard from the Gobi Desert of Mongolia, is a key fossil for understanding gecko phylogeny. We revisit this fossil using high‐resolution X‐ray computed tomography. The application of this imaging method reveals new information about sutures, bone shape, and structural details of the palate and basicranium. These data were used to assess the phylogenetic affinities of Gobekko in the context of an existing squamate data set. The effects of character ordering, search strategy, and the addition of another putative gekkonomorph (Hoburogekko suchanovi) on inferred gekkonomorph relationships were explored. Available specimens of G. cretacicus are skeletally mature but have unfused nasals, frontals, and parietals, and (possibly) a persistent basicranial fenestra. Some putative gekkonomorphs are not consistently supported as closer to crown clade gekkotans than to autarchoglossans. In a strict consensus both Gobekko and Hoburogekko form a polytomy with extant geckos. Some of the adult character states of Gobekko are observable in embryos of extant species. The evolution of tubular frontals and dentaries in gekkotans may be structurally related to the loss of the postorbital and supratemporal bars in this lineage. The complete lack of a parietal foramen, and presumably a light‐sensitive parietal eye, in this clade is of interest and could indicate an early origin of nocturnality in geckos. © 2013 The Linnean Society of London  相似文献   

18.
大蚊属Tipula Linnaeus,1758是大蚊科中种类最多的属,目前其单系性尚未得到全面验证.此外,长角大蚊亚属Tipula (Sivatipula) Alexander,1964因其极长的触角以及独有的精子泵结构,明显不同于大蚊属其他亚属,使其亚属的分类地位存在争议.本研究基于COI序列对19个大蚊属物种及5个其他属物种进行了系统发育分析,并计算了物种间的遗传距离.研究结果表明:(1)邻接树(NJ)和最大似然树(ML)均显示长角大蚊亚属与大蚊属其他亚属未形成单系,大蚊属的单系性没有得到支持;(2)基于遗传距离和系统发育分析并结合形态信息,结果显示长角大蚊亚属独立于大蚊属内其他亚属,应将其提升为属级分类单元.  相似文献   

19.
水螨群总科阶元系统发育的支序分析 (蜱螨亚纲:水螨群)   总被引:1,自引:0,他引:1  
金道超 《昆虫学报》2000,43(3):309-317
对水螨群9总科进行了系统发育分析,支序分析选用了23个形态学特征和3个生物学特征。据分析结果所揭示的9总科间的系统发育关系和姐妹群关系,将水螨群9总科划分为5类:拟水螨类,含冥绒螨总科;始水螨类,含溪螨总科;真水螨类,含古水螨类和新水螨类;古水螨类,含水螨总科、盾水螨总科和皱喙螨总科;新水螨类,含刺触螨总科、腺水螨总科、湿螨总科和雄尾螨总科。类间姐妹群关系为:拟水螨类与始水螨类+真水螨类为姐妹群,始水螨类与真水螨类(古水螨类+新水螨类)为姐妹群,古水螨类与新水螨类为姐妹群。该文还就所提出的水螨群5类9总科的阶元排列建议与已有的观点进行了比较。  相似文献   

20.
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