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1.
This paper studies the phylogenetic relationships of the nudibranch dorids that lack a radula. Numerous specimens belonging to 29 different species, representing all genera of this group and other related taxa, were examined anatomically. Details of the foregut were examined with SEM. From this anatomical study a total of 62 characters were considered. These characters have been polarized using the genus Berthella as the outgroup. Eight species of dorids with a radula and the genus Armina have been also included in the analysis for comparative purposes. The phylogeny obtained supports the hypothesis that the radula has been lost once in the Doridina and that the radula-less dorids are a monophyletic group. Cryptobranchia is monophyletic when the radula-less dorids are included. The new genus Mandelia , introduced on the basis of a new species from South Africa, is the sister group of the rest of the radula-less dorids, and is described as a new family, Mandeliidae. The radula-less dorids (currently placed in a separate superfamily) actually constitute an internal branch of other cryptobranch dorids. Phyllidia has no synapomorphies that distinguish if from Fryeria , which has one autoapomorphy, the ventral position of the anus. Therefore, both genera are regarded as synonyms. The evolution of several characters among the radula-less dorids is discussed, and the present phylogeny is compared with prior studies.  相似文献   

2.
对螟黄足盘绒茧蜂复合群Cotesia flavipes complex (膜翅目:茧蜂科:小腹茧蜂亚科)分布全世界的5个种和外群侧沟茧蜂Microplitis 及荻茧蜂Diolcogaster 的25个性状,以及复合群5个种和外群螟蛉盘绒茧蜂Cotesia ruficrus、粘虫盘绒茧蜂Cotesia kariyai、粉蝶盘绒茧蜂Cotesia glomerata 的24个性状,分别进行比较研究,并运用支序分析的方法探讨该复合群内5个种种间的系统发育关系。支序分析表明螟黄足盘绒茧蜂复合群是一单系群,二化螟盘绒茧蜂C. chilonis 和大螟盘绒茧蜂C. sesamiae 近缘,芦螟盘绒茧蜂C. chiloluteelli 和汉寿盘绒茧蜂C. hanshouensis 近缘,螟黄足盘绒茧蜂C. flavipes相对独立。 以上研究表明无论是以近缘属作外群还是以同属其它种作外群,所得结果基本上都能反映螟黄足盘绒茧蜂复合群各种之间的分类地位。  相似文献   

3.
The utility of a nuclear protein-coding gene for reconstructing phylogenetic relationships within the family Culicidae was explored. Relationships among 13 species representing three subfamilies and nine genera of Culicidae were analyzed using a 762-bp fragment of coding sequence from the eye color gene, white. Outgroups for the study were two species from the sister group Chaoboridae. Sequences were determined from clone PCR products amplified from genomic DNA, and aligned following conceptual intron splicing and amino acid translation. Third codon positions were characterized by high levels of divergence and biased nucleotide composition, the intensity and direction of which varied among taxa. Equal weighting of all characters resulted in parsimony and neighboring-joining trees at odds with the generally accepted phylogenetic hypothesis based on morphology and rDNA sequences. The application of differential weighting schemes recovered the traditional hypothesis, in which the subfamily Anophelinae formed the basal clade. The subfamily Toxorhynchitinae occupied an intermediate position, and was a sister group to the subfamily Culicinae. Within Culicinae, the genera Sabethes and Tripteroides formed an ancestral clade, while the Culex-Deinocerites and Aedes- Haemagogus clades occupied increasingly derived positions in the molecular phylogeny. An intron present in the Culicinae- Toxorhynchitinae lineage and one outgroup taxon was absent in the basal Anophelinae lineage and the second outgroup taxon, suggesting that intron insertions or deletions may not always be reliable systematic characters.   相似文献   

4.
Aldo Poiani 《Oecologia》1992,92(3):429-441
The hypothesis that cooperative breeding entails a cost in terms of transmission of ectoparasites was tested by a comparative analysis among sympatric Australian passerines. The general trend found using the allometry method and outgroup analysis indicates that contagious ectoparasites are not more common on cooperatively breeding than on non-cooperatively breeding hosts. Body weight, migratory patterns and relative abundance of hosts are factors far more important than cooperative breeding that affect the levels of ectoparasitism in the host genera studies. Ectoparasitism increases with host body weight and relative adundance, while sedentary host genera tended to show less hippoboscid fly diversity than migratory host genera. There is an interaction between breeding system and migratory pattern when relative density of contagious ectoparasites (i.e. mites, ticks and bird lice) is considered: the number of contagious ectoparasites per host is larger on cooperatively breeding host genera than on non-cooperatively breeding host genera among sedentary passerines, but the trend is reversed for migrant passerines.  相似文献   

5.
A cladistic analysis of Lophopidae was performed, using 73 observed morphological characters and 41 taxa. This analysis involved 36 genera belonging to the Lophopidae family and 5 outgroups. For a better understanding of the selected characters some illustrations are provided. The most parsimonious cladograms obtained show that the Lophopidae cannot be considered as a monophyletic lineage unless two genera are withdrawn from this family: Hesticus Walker, 1862, and Silvanana Metcalf, 1947. The systematic position of these two genera remains uncertain. They cannot yet be included in another family of Fulgoromorpha. A cladistic analysis of each of the 19 remaining Fulgoromorphan families must be performed first. A new family could be created for these two genera, but not before we are sure that these two genera are in no way members of an existing family. The outgroup problem is discussed. The monophyletic lineage represented by the Lophopidae can be divided into four natural groups: Carriona+, Makota+, Sarebasa+, and Bisma+. When a cladistic analysis is completed using a data matrix without characters linked to females, the cladogram obtained presents a disrupted basal resolution. Female characters appear to bring a phylogenetic signal important basally in the evolution of the Lophopidae but also apically, directly between the relationships of some genera. A similar analysis, using a matrix without characters linked to males, provides a phylogeny disrupted between the groups that form the Lophopidae and in the basal resolution in these groups. The respective impacts of the genitalic characters are discussed in relation to sexual selection conflict.  相似文献   

6.
用支序分类的方法分析了我国北方网蝽亚科内16个属间的系统演化关系,在比较形态研究的基础上选取该亚科的33个特征、88个特征状态,通过内群和外群比较的方法对特征状态进行极化,形成特征状态矩阵,,分别使用计算机编码程序PAUP(version3.1.1)和Hennin86(version1.5)进行运算分析,得到完全一致的最简约树及Nelson合意树(树长L=118步,一致性指数CI=0.454,保留指数RI=0.529)。用以分析亚科内属级分类单元之间分类单元可归为6个群,分别为A-gramman群、Leptoyha群、Dictyla群、Catophatus群、Physatoheila群和Derephysia群,Agramma群在所分析的类群中是为原始的一群,最早由基部分出,与由Leptoypha群、Dictyla群、Catoplatus群、P hysatocheila群和Derephysia群构成的单系形成姐妹群。Leptoypha群也是较早分出的一群,与由Dictyla群、Catoplatus群、Physatochila群和为一单系,是最为进化的一群,与另一较进化的Physatocheila群单系构成1对姐妹群。此两群所构成的单系群又与Catoplatus群构成姐妹群,形成一个单系群,继而与Dictyla群单系构成姐妹群。用AutoDecay(version3.0)对各分支点进行了分支支持分析。这些群在更多的属级单元参加分析之前暂不划为高一级的分类单元。  相似文献   

7.
This paper proposes a refined hypothesis of evolution for the tropical Indo-Pacific nudibranch genus Halgerda . Numerous specimens from 31 species were examined anatomically and literature from four additional species was reviewed, bringing to 33 the ingroup taxa. Fifty-three characters were considered from these examinations. The outgroup Asteronotus was used to polarize the characters. The phylogeny obtained from the analysis of the characters supports the hypothesis that Halgerda is a monophyletic group. A species previously placed with the genus Sclerodoris is examined and determined to be a member of the genus Halgerda . Phylogenetic analysis places this species, H. paliensis , as a basal member of the genus . Halgerda paliensis appears to be restricted to the Hawaiian Islands. Specimens previously identified as Sclerodoris paliensis from the Marshall Islands actually represent H. dalanghita Fahey & Gosliner, 1999. A new species, Halgerda onna , is described and presented as the sister taxon to a basal member of the genus. A range and depth extension of a previously described species, H. malesso , is presented. The present phylogeny is then compared to previous studies, in particular those of Fahey & Gosliner (1999a,b) .  相似文献   

8.
This study presents a new phylogeny of erigonine spiders with emphasis on genera from the Neotropics. Thirty‐nine exemplar taxa representing mostly Neotropical genera were added to a global sample of 31 erigonine and 12 outgroup exemplar taxa analyzed in a previous study. These 82 taxa were coded for 176 (172 informative) mostly morphological characters. Eighty‐one characters were identical to or modified from the 73 (67 informative) characters included in a previous study; the remaining 95 characters are new. The complete data set includes 70 erigonine exemplars representing 65 genera, seven nonerigonine linyphiid exemplars, and five exemplars representing four araneoid families in the outgroup. Cladistic analysis resulted in a single most parsimonious tree (L =904, CI = 0.23, RI = 0.58; uninformative characters excluded: L = 900, CI = 0.23). This paper explores the implications of the new topology for the evolution of several characters of interest in erigonine evolution. The phylogeny implies that the desmitracheate condition is a synapomorphy of erigonines, with a reversal to the haplotracheate condition in one large clade within Erigoninae. We infer that the loss of the paracymbium in Neotropical erigonines occurred twice and may have progressed by different evolutionary pathways. Our phylogeny differs markedly from the previous cladistic hypothesis of erigonine relationships. We investigate how the addition of characters and taxa (alone and together) have altered the earlier hypothesis of erigonine phylogeny. We conclude that topological changes from the previous study to the current one are largely the result of adding and modifying characters, not adding taxa. Continuous Jackknife Function (CJF) analysis predicts that the inclusion of additional character data will continue to imply changes in the relationships among taxa in our analysis.  相似文献   

9.
This study presents a general cladistic analysis of pisaurid genera, with emphasis on the Neotropical genera Architis Simon and Staberius Simon. The analysis was based on a matrix with 21 terminal taxa: eight species of Architis , Staberius spinipes (Taczanowski), seven exemplars of other pisaurid genera and five outgroup taxa. These terminals were scored for 59 morphological and three behavioural characters. An analysis with all characters equally weighted resulted in two most parsimonious trees, differing only in the position of Architis colombo Santos. In both trees Pisauridae arouse as a monophyletic group, and the exemplars of Architis composed a clade with S. spinipes . Contrary to hypotheses from the literature, Thalassius Simon emerged as sister-group of all remaining pisaurids, not as a close relative of Dolomedes Latreille. The genera Tinus F.O.P. -Cambridge and Thaumasia Perty appeared in the trees as the closest relatives of Architis and Staberius Simon. The analysis strongly supported S. spinipes as the sister-group of A. helveola (Simon), indicating that Architis as currently delimited is paraphyletic. Based on these results, Staberius is considered a subjective junior synonym of Architis . Additionally, the genus Mimicosa Petrunkevitch, originally described in Tetragnathidae, is transferred to Pisauridae and considered a junior synonym of Architis . Two species are proposed as junior synonyms of A. spinipes comb.n. Mimicosa spinosa Petrunkevitch and Staberius lemoulti Caporiacco.  相似文献   

10.
似鮈类鱼类的系统发育研究(鲤形目:鲤科)   总被引:1,自引:0,他引:1  
本文通过对似类8属13种和外类群7属10种鱼类的比较研究,选取37个骨骼及外部特征,运用外类群比较法进行特征分析,根据分支系统学原理重建了似类的系统发育。特征分析和系统发育分析表明似类是具有许多共同离征的单系群,朝着流水性底栖生活和刮食性的主干方向发展;其中以似属最原始,胡属最特化构成7对姐妹群。蛇属是较早分化出的相对特化的类群,棒花鱼属和小鳔属的关系相对较远。  相似文献   

11.
A cladistic analysis of all known genera in the Carangidae was made mostly on the basis of external and osteological characters. Polarity for each character was determined by outgroup comparison using the echeneoids as the first outgroup and the Nematistiidae as the second. In the Carangini, there were four hypothesized monophyletic groups at the rank of sub-tribe. Parastromateus is the sister group of the remaining twenty-one carangine genera which are divided into three groups. The first group consists of a single genus Megalaspis. The second group is composed of Trachurus, Decapterus, Selar, Atule, Selaroides, Pantolabus, Alepes, Hemicaranx, Pseudocaranx, Kaiwarinus, and Chloroscombrus. The third group comprises Uraspis Caranx, Gnathanodon, Carang ichthys, Carangoides, Atropus, Ulua, Alectis, and Selene.  相似文献   

12.
Abstract.  A cladistic analysis of Neotropical Protoneuridae was performed on a data matrix of 48 morphological characters and 43 terminal taxa. Representatives of Paleotropical Protoneuridae, Platycnemididae and Isostictidae were included to test their relationships with Neotropical Protoneuridae. Coenagrionidae was chosen as the outgroup, but alternative analyses with Platycnemididae as the outgroup were also performed. Protoneuridae appears as a polyphyletic clade, with its Paleotropical component being more closely related to Platycnemididae and Isostictidae. Neotropical Protoneuridae appear as a monophyletic clade; included genera considered monophyletic or valid monotypic taxa are Epipleoneura Williamson, 1915 ; Idioneura Selys, 1860; Junix Rácenis, 1968; Neoneura Selys, 1860; Peristicta Hagen in Selys, 1860; Roppaneura Santos, 1966; and Lamproneura De Marmels, 2003. A key to the Neotropical Protoneuridae genera is included.  相似文献   

13.
The phylogenetic relationships of the Amphitritinae (Polychaeta: Terebellidae) were studied using parsimony analysis of 22 external morphological characters. To choose outgroups to polarize the characters, I carried out a preliminary analysis of the relationships of the four terebellid subfamilies and the Trichobranchidae. The single most parsimonious tree from the analysis supports monophyly of the Terebellidae by the presence of ventral glandular shields. However, this character is homoplasious within the Terebellomorpha, and further evaluation of the Terebellidae is recommended. Artacama and Thelepus were chosen as outgroups for the analysis of amphitritine genera. The generic level analysis yielded seven equally parsimonious trees, which are consistent in their topologies except for the relationships among seven genera in one large clade. In all trees, Artacama is the sister taxon to a large clade within the Amphitritinae; the Artacaminae is therefore synonymized with the Amphitritinae, which is diagnosed by the presence of double rows of uncini. Within the Amphitritinae, the status of several monotypic genera is questioned; plesiomorphic character states indicated by the analysis are discussed. The results presented are offered as working hypotheses of the relationships among amphitritine genera. The large number of homoplasies indicated by the analysis emphasizes the need to further evaluate these hypotheses using additional characters. With a robust phylogenetic hypothesis of amphitritine relationships, a re-classification of the group based on apomorphic character states can be undertaken, and questions regarding the evolution of morphological characters, reproductive modes, or biogeographical patterns can be properly addressed.  相似文献   

14.
Abstract. The type genus for the dragonfly family Libellulidae is Libellula. At present, Libellula s.l. includes twenty-nine species, whose distribution is largely Nearctic. Whether two other libellulid taxa, Ladona and Plathemis, should be considered synonyms of Libellula, subgenera of Libellula, or separate genera, has been a subject of intermittent debate for over a century. Earlier proposals concerning Ladona and Plathemis were based on a limited number of morphological characters and lacked rigorous phylogenetic analyses. Therefore, we used the DNA sequence of a portion of the mitochondrial 16S rRNA gene and parsimony, maximum likelihood and neighbour-joining analyses to explore whether Ladona and Plathemis are monophyletic lineages distinct from Libellula. We obtained ≈ 415 bp of DNA sequence from twenty-three taxa including thirteen species of Libellula s.s., all three recognized species of Ladona, the two species of Plathemis and representatives of four other libellulid genera. Tetragoneuria williamsoni (Odonata: Corduliidae) was included as the outgroup. Parsimony analysis suggested that Ladona and Plathemis are monophyletic lineages distinct from Libellula s.s. with a sister group relationship between Libellula and Ladona. The monophyly of Ladona, Plathemis and Libellula was supported in > 90% of bootstrap replications and in trees five to ten steps longer than the most parsimonious trees. Relationships inferred from maximum likelihood and neighbour-joining analyses also supported the monophyly of Ladona and Plathemis. The four other libellulid genera included in the study formed a monophyletic clade distinct from Libellula, Ladona and Plathemis. Based on our analysis, we propose that Ladona and Plathemis be considered either genera or subgenera within Libellulidae.  相似文献   

15.
A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pleurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and Arpophyllinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phylogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pleurothallis is not a natural genus and, perhaps may be divided into several discrete genera.  相似文献   

16.
A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pkurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and ArpophyUinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phytogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pkurothallis is not a natural genus and, perhaps may be divided into several discrete genera.  相似文献   

17.
Abstract— A cladistic analysis based on 50 morphological characters was performed for 49 of the 98 species currently assigned to the subclass Palaeonemertea (phylum Nemertea), and six additional undescribed species. Thirty-five species were excluded from the parsimony analysis because of the high number of unknowns in the character matrix, and one species since it was considered a nomen nudum . An initial analysis suggested that the subclass Hoplonemertea is the sistergroup to the clade Palaeo- and Heteronemertea and the ingroup cladograms are rooted using a paraphyletic outgroup based on this information. Seventy-two equally most parsimonious cladograms were found; the consistency index was low but tree-length distribution for the character set is skewed to the left, and the cladograms are invariably shorter than trees based on random data. These cladograms suggested a character transformation series for the cerebral organ where this complex character reappeared several times after being absent. We considered this biologically implausible and the final discussion is based on three cladograms, one step longer than the most parsimonious, where the evolution of this character appears to be more realistic. The cladistic analysis indicates that many previously recognized genera (e.g. Cephalothrix, Procephalothrix and Cephalotrichella ), and higher taxa, are paraphyletic. It furthermore indicates that the previously suggested hypothesis of the Archinemertea as a monophyletic sistertaxon to Palaeonemertea is unsupported.  相似文献   

18.
A phylogeny of sparoid fishes (Perciformes, Percoidei) based on morphology   总被引:2,自引:0,他引:2  
 The putative percoid superfamily Sparoidea includes the Nemipteridae, Lethrinidae, Sparidae, and Centracanthidae. Although a rigorous cladistic analysis has never been attempted, two hypotheses regarding relationships among these families have been proposed. One early noncladistic hypothesis considered the Sparidae to be intermediate between the more primitive Nemipteridae and the more derived Lethrinidae. A later nonformal phylogenetic treatment provided evidence for a close relationship between Sparidae and Centranthidae and suggested a closer affinity between the Nemipteridae and Lethrinidae. We examine 54 osteological, ligament, and squamation characters in representatives of all 45 genera of these families and 4 outgroup taxa. The results of our cladistic analysis are congruent with a cladistic interpretation of the earlier hypothesis, with strong support for the phyletic sequence Nemipteridae, Lethrinidae, Sparidae plus Centracanthidae, with placement of centracanthids unresolved with respect to sparid genera. Received: May 21, 2001 / Revised: October 26, 2001 / Accepted: November 19, 2001  相似文献   

19.
论山毛榉科植物的系统发育   总被引:10,自引:2,他引:8  
本文运用分支分类学方法,对山毛榉科植物进行了系统发育的分析。山毛榉科作为单元发生群包括柯属、锥属、粟属、三棱栎属、水青冈属和栎属。桦木科和南山毛榉属被选择作为外类群。对大量的性状进行评估之后,选择了25对性状作为建立数据矩阵的基本资料。性状极化以外类群比较为主,同时也采用了化石证据和通行的形态演化的基本原则。数据矩阵由7个分类群、2个外类群和25个性状组成。采用最大同步法、演化极端结合法和综合分析法对该数据矩阵进行了分析。在得到的3个树状分支图中按照最简约的原则,选出演化长度最短的谱系分支图作为本文讨论山毛榉科属间的系统演化关系的基础。关于山毛榉科植物的系统发育,作者的观点如下:(A)现存的山毛榉科的6个属形成了4条平行进化的分支路线,它们分别被处理作4个亚科,即:栗亚科,三棱栎亚科,水青冈亚科和栎亚科;(B)平行进化是山毛榉科植物系统发育过程中的主要形式。生殖过程中的一些特征,如:果实第二年成熟,胚珠通常败育等,是影响山毛榉科植物属间基因交流的主要原因。在现存的山毛榉科植物中,柯属是最原始的类群。三棱栎属和锥属的起源也较早,而栗属、水青冈属和栎属是特化的类群。  相似文献   

20.
GRAHAM, S. A., CRISCI, J. V. & HOCH, P. C, 1993. Cladistic analysis of the Lythraceae sensu lato based on morphological characters. The Lythraceae s. I. comprise 31 mostly highly distinctive genera distributed worldwide. Cladistic analyses of the family were undertaken using 26 characters from anatomy, floral morphology, pollen, and seed morphology. Of four outgroup hypotheses, the Onagraceae offered the best heuristic assessment, generating 3746 trees with a tree length of 83 and consistency index and (C.I.) of 0.41. A strict consensus tree from the 3746 trees produced a basal monophyletic group of five genera (Sonneratia, Duabanga, Punka, Lagerstroemia, Lawsonia) characterized by anthotelic (determinate) inflorescences and wet stigmas, and a second clade with blastotelic (indeterminate) inflorescences, dry stigmas, and reduced carpel number. Successive weighting with Onagraceae as outgroup generated five most parsimonious trees with a tree length of 164 and C.I. of 0.75. Internal branches are weakly supported by only seven non-homoplasious characters. Significant results of the analysis include: (1) recognition of the two major clades and a total of seven monophyletic groups within the family; (2) the paraphyly of subfamily Lythroideae (Lythraceae s. s .); and (3) indication that genera endemic to the New World have been derived from more than one ancient Old World evolutionary line. The current taxonomic classification of the family is not closely correlated with results of the cladistic analysis.  相似文献   

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