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1.
Despite the ubiquity of obligate mutualisms on coral reef ecosystems, little is known about the evolution of many participating species. The shrimp gobies, known primarily from the coral reef habitats of the Indo-Pacific, are small benthic fishes that participate in a remarkable mutualism with alpheid shrimp. In this mutualism, the shrimp build and maintain a burrow that is guarded by the goby, and the shrimp and goby engage in an intricate tactile communication system. The mutualism is obligate for most shrimp gobies as participating species are highly vulnerable to predation when separated from a shrimp partner. We use phylogenetic analysis of nuclear and mitochondrial DNA sequence data to infer evolutionary relationships among shrimp gobies, and between shrimp gobies and their non-mutualistic gobiid relatives. We show that the mutualist shrimp association has arisen twice among gobies, once in a clade composed of Amblyeleotris, Ctenogobiops, and Vanderhorstia, and a second time in a clade including Cryptocentrus, Mahidolia, Tomiamichthys and Stonogobiops. We then compare the evolution of traits within each shrimp goby clade and consider their intrarelationships. We document cryptic diversity among shrimp gobies, with three distinct clades delineated among Mahidolia mysticina specimens captured at the same locality, paired with the same shrimp species. Mahidolia is placed as sister to the Cryptocentrus species Cryptocentrus cinctus; both exhibit pronounced dichromatism, occurring in both brown and yellow (xanthic) forms. We additionally clarify species identities within Amblyeleotris, confirming that widespread similar species Amblyeleotris fasciata, Amblyeleotris steinitzi and Amblyeleotris wheeleri are all distinct. We hypothesize that the flexibility of gobiid gobies and alpheid shrimp to interact with mutualist partners, as well as the apparently highly beneficial nature of mutualism between them, has contributed to the dual evolution of shrimp-association among Indo-Pacific gobies.  相似文献   

2.
The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.  相似文献   

3.
Apiomerus, the charismatic bee-assassins (>108 spp.), belong to the New World resin bugs in the harpactorine tribe Apiomerini (12 extant genera) that is characterized by a novel predation strategy, resin trap predation. Apiomerini also exhibit striking genitalic diversity that has shaped subgeneric classifications within the genus Apiomerus and females of some species of Apiomerus are known to engage in unique maternal care behaviors. The lack of a phylogenetic framework currently hinders evolutionary interpretations of genitalic morphology and maternal care. We here present a molecular phylogeny based on 4, 477 bp of six ribosomal and protein coding genes and 95 terminal taxa using parsimony and maximum likelihood approaches as a way of addressing these shortcomings. Apiomerini are monophyletic, with Heniartes being the sistergroup to all remaining taxa that form the monophyletic Manicocoris (Calliclopius, Manicocoris, Micrauchenus, and Ponerobia) and Apiomerus (Agriocoris, Apiomerus, and Sphodrolestes) clades. Previously proposed subgeneric groups are polyphyletic, but several proposed species groups are recovered as monophyletic. Ancestral state reconstruction of the metatibial comb indicates that this structure evolved in the ancestor of all Apiomerini where it was present in males and in females; it became strongly sexually dimorphic (better developed in females than in males) in the Apiomerus clade (Apiomerus + Agriocoris + Sphodrolestes). Genitalic features reveal a pattern of homoplasy, but frequently are nonetheless useful to diagnose supraspecific groups within Apiomerus. The complex genitalia found within Apiomerus are derived for that clade. We conclude that, using the metatibial comb as a proxy, maternal care is relatively common in the tribe Apiomerini and propose that it likely evolved at the base of the Apiomerus clade if not at the base of Apiomerini.  相似文献   

4.
Pyroleae (Ericaceae) consist of four genera, all of which are distributed widely in temperate coniferous or sometimes deciduous forests of the Northern Hemisphere. To investigate the phylogenetic relationships among these genera and to explore the evolution of the characteristics of the subfamily, we conducted maximum parsimony and Bayesian analyses with nrDNA ITS and three cpDNA intergenic spacers (atpB-rbcL, trnS-trnG and trnL-trnF). The results from cpDNA and combined cpDNA + ITS data sets strongly support the monophyly of Pyroleae as well as a sister relationship between Pyrola and MonesesChimaphila, with Orthilia as the basal lineage. The sister-group relationship between Moneses and Chimaphila is supported by a set of synapomorphies, e.g., single flower, colpate pollen, five bundles in the style, straight fruiting pedicel orientation, complete capsule dehiscence, and the basic chromosome number, x = 13. The MonesesChimaphilaPyrola clade is supported by at least one homologous character of pollen in tetrads. Conflicts associated with the phylogenetic position of Orthilia may imply a hybrid origin for it, and therefore further study is needed.  相似文献   

5.
6.
The phylogeny of the genera traditionally classified in the family Pluteaceae (Agaricales, Basidiomycota) was investigated using molecular data from nuclear ribosomal genes (nSSU, ITS, nLSU) and consequences for taxonomy and character evolution were evaluated. The genus Volvariella is polyphyletic, as most of its representatives fall outside the Pluteoid clade and shows affinities to some hygrophoroid genera (Camarophyllus, Cantharocybe). Volvariella gloiocephala and allies are placed in a different clade, which represents the sister group of Pluteus, and a new generic name, Volvopluteus, is proposed to accommodate these taxa. Characters such as basidiospore size and pileipellis structure can be used to separate Pluteus, Volvariella and Volvopluteus. The genus Pluteus is monophyletic and includes species with partial veil traditionally classified in the genus Chamaeota. The evolution of morphological features used in the infrageneric taxonomy of the genus, such as metuloid cystidia and pileipellis structure, was analyzed. Agreement between the molecular phylogeny and morphological subdivision of Pluteus is, generally speaking, good, though some rearrangements are necessary: (i) species with non-metuloid pleurocystidia and pileipellis as a cutis are placed either in sect. Celluloderma, together with the species characterized by a hymenidermal pipeipellis, or in sect. Pluteus, with the metuloid bearing species; (ii) subdivision of sect. Celluloderma according to the presence/absence of cystidioid elements in the pileipellis is not supported by molecular data.  相似文献   

7.
Phylogeny, character evolution, and classification of Sapotaceae (Ericales)   总被引:2,自引:0,他引:2  
We present the first cladistic study of the largely tropical family Sapotaceae based on both morphological and molecular data. The data were analyzed with standard parsimony and parsimony jackknife algorithms using equally and successive weighted characters. Sapotaceae are confirmed to constitute two main evolutionary lineages corresponding to the tribes Isonandreae‐Mimusopeae‐Sideroxyleae and Chrysophylleae‐Omphalocarpeae. The Sideroxyleae are monophyletic, Isonandreae are polyphyletic as presently circumscribed, and as suggested by the analyses, the subtribe Mimusopeae‐Mimusopinae has evolved within the Mimusopeae‐Manilkarinae, which hence is also paraphyletic. Generic limits must be altered within Sideroxyleae with the current members Argania, Nesoluma and Sideroxylon. Argania cannot be maintained at a generic level unless a narrower generic concept is adopted for Sideroxylon. Nesoluma cannot be upheld in a narrow or broad generic concept of Sideroxylon. The large tribe Chrysophylleae circumscribes genera such as Chrysophyllum, Pouteria, Synsepalum, and Xantolis, but the tribe is monophyletic only if the taxa from Omphalocarpeae are also included. Neither Chrysophyllum nor Pouteria are monophyletic in their current definitions. The results indicate that the African taxa of Pouteria are monophyletic and distinguishable from the South American taxa. Resurrection of Planchonella, corresponding to Pouteria section Oligotheca, is proposed. The African genera Synsepalum and Englerophytum form a monophyletic group, but their generic limits are uncertain. Classification of the Asian genus Xantolis is particularly interesting. Morphology alone is indecisive regarding Xantolis relationships, the combined unweighted data of molecules and morphology indicates a sister position to Isonandreae‐Mimusopeae‐Sideroxyleae, whereas molecular data alone, as well as successive weighted combined data point to a sister position to Chrysophylleae‐Omphalocarpeae. An amended subfamily classification is proposed corresponding to the monophyletic groups: Sarcospermatoideae (Sarcosperma), Sapotoideae (Isonandreae‐Mimusopeae‐Sideroxyleae) and Chrysophylloideae (Chrysophylleae‐Omphalocarpeae), where Sapotoideae circumscribes the tribes Sapoteae and Sideroxyleae as well as two or three as yet unnamed lineages. Morphological characters are often highly homoplasious and unambiguous synapomorphies cannot be identified for subfamilies or tribes, which we believe are the reason for the variations seen between different classifications of Sapotaceae. © The Willi Hennig Society 2005.  相似文献   

8.
Selaginella is the largest and most taxonomically complex genus in lycophytes.The fact that over 750 species are currently treated in a single genus makes Selaginellales/Selaginellaceae unique in pteridophytes.Here we assembled a dataset of six existing and newly sampled plastid and nuclear loci with a total of 684 accessions(74% increase of the earlier largest sampling) representing ca.300 species to infer a new phylogeny.The evolution of 10 morphological characters is studied in the new phylog...  相似文献   

9.
The Tremellomycetes (Agaricomycotina, Basidiomycota, Fungi) are a nutritionally heterogeneous group comprising saprotrophs, animal parasites, and fungicolous species (fungal-inhabiting, including lichen-inhabiting). The relationships of many species, particularly those with a lichenicolous habit, have never been investigated by molecular methods. We present a phylogeny of the Tremellomycetes based on three nuclear DNA ribosomal markers (nSSU, 5.8S and nLSU), representing all main taxonomic groups and life forms, including lichenicolous taxa. The Cystofilobasidiales, Filobasidiales, Holtermanniales, and Tremellales (including the Trichosporonales) are recovered as monophyletic, but this is not the case for the Tremellomycetes. We suggest, however, that the Cystofilobasidiales tentatively continue to be included in the Tremellomycetes. As currently circumscribed, the Filobasidiaceae, Sirobasidiaceae, Syzygosporaceae and Tremellaceae are non-monophyletic. Cuniculitremaceae, Sirobasidiaceae and Tetragoniomycetaceae are nested within Tremellaceae. The lichenicolous species currently included within the Tremellomycetes belong in this group, distributed across the Filobasidiales and Tremellales. Lichen-inhabiting taxa do not form a monophyletic group; they are distributed in several clades and sometimes intermixed with taxa of other nutritional habits. Character state reconstruction indicates that two morphological traits claimed to characterize groups in the Tremellomycetes (the basidium habit and basidium septation) are highly homoplastic. Comparative phylogenetic methods suggest that the transitions between single and catenulate basidia in the Tremellales are consistent with a punctuational model of evolution whereas basidium septation is likely to have evolved under a graduational model in the clade comprising the Holtermanniales, Filobasidiales, and Tremellales.  相似文献   

10.
11.
Fumana is a diverse genus of the Cistaceae family, consisting of 21 currently accepted species. In this study, nuclear (ITS) and plastid (matK, trnT‐L) molecular markers were used to reconstruct the phylogeny and to estimate divergence times, including 19 species of Fumana. Phylogenetic analyses (Bayesian Inference, Maximum Parsimony and Maximum Likelihood) confirmed the monophyly of Fumana and did not support the infrageneric divisions previously established. The results support four main clades that group species that differ in vegetative and reproductive characters. Given the impossibility to define morphological characters common to all species within the clades, our proposal is to reject infrageneric divisions. Molecular dating and ancestral area analyses provide evidence for a Miocene diversification of the genus in the north‐western Mediterranean. Ancestral state reconstructions revealed ancestral character states for some traits related to xeric and arid habitats, suggesting a preadaptation to the Mediterranean climate.  相似文献   

12.
The phylogeny of the Mexican lizard genus Barisia was assessed using an 878 bp fragment of the mtDNA ND4 gene and a section of associated tRNA genes, as well as 16 external morphological characters. The terminal taxa comprised the currently recognized members of Barisia, including the four subspecies of the polytypic Barisia imbricata and individuals from different populations of the widespread B. i. imbricata and Barisia i. ciliaris, although for Barisia levicollis only morphology could be examined. The ‘step‐matrix frequency’ and the ‘step‐matrix gap‐weighting’ coding approaches were employed simultaneously for the morphological data set, and three different scaling methods were evaluated for the last approach. Maximum parsimony (MP) analyses were performed for the separate and combined data sets and Bayesian analysis was also performed for the mtDNA sequence data. The hypothesis obtained from the simultaneous MP analysis strongly supports the monophyly of Barisia, but the ‘exclusivity’ of B. imbricata as well as of B. i. imbricata and B. i. ciliaris were not recovered. Moreover, inclusion of the morphological data showed B. levicollis nested within a clade together with the taxa assigned to B. i. ciliaris. This, together with the genetic distances and geographic concordance among the haplotypes examined, confirms that B. imbricata represents several species, although the actual species limits in this composite taxon are still unclear. Applying previously published rates of molecular evolution to the mtDNA data gives ages of divergence similar to the times proposed for some Pleistocene–Miocene geological and climatic phenomena that occurred in the Mexican territory. Variation of the dorsal pattern within Barisia was mapped onto the simultaneous morphological and molecular phylogeny, indicating that the two main states present in the taxa assigned to B. imbricata, an adult dorsal pattern present in females and absent in males and the absence of any pattern in both sexes, occur each in separate lineages. This suggests a possible scenario, where sexual dichromatism within Barisia has been repeatedly lost in different lineages.  相似文献   

13.
This study uses histological techniques to make a detailed comparison of the reproductive morphologies of four gobiid genera, Amblyeleotris, Ctenogobiops, Fusigobius and Kraemeria. Three distinct reproductive morphological patterns were observed. All species examined in the genus Fusigobius exhibit either an ovariform or testiform gonad and precursive accessory gonadal structures (pAGS) associated with each of the gonadal lobes, regardless of gonadal state. In contrast, among species of Amblyeleotris, Ctenogobiops and Kraemeria examined, pAGS were not found. Furthermore, Amblyeleotris and Ctenogobiops differ from both Kraemeria and Fusigobius in lacking AGS associated with the testiform gonad. These findings, based solely on reproductive morphology, suggest that Kraemeria and Fusigobius may be more closely related to each other than either is to Amblyeleotris and Ctenogobiops. Findings of this study support the view that reproductive morphological patterns could prove informative in elucidating evolutionary relationships within the family Gobiidae.  相似文献   

14.
With c. 85 species, the genus Micranthes is among the larger genera of the Saxifragaceae. It is only distantly related to the morphologically similar genus Saxifraga, in which it has frequently been included as Saxifraga section Micranthes. To study the molecular evolution of Micranthes, we analysed nuclear ribosomal (internal transcribed spacer, ITS) and plastid (trnLtrnF) DNA sequences in a comprehensive set of taxa comprising c. 75% of the species. The molecular phylogenetic tree from the combined dataset revealed eight well‐supported clades of Micranthes. These clades agree in part with previously acknowledged subsections or series of Saxifraga section Micranthes. As these eight groups can also be delineated morphologically, we suggest that they should be recognized as sections of Micranthes. New relationships were also detected for some species and species groups, e.g. section Davuricae sister to sections Intermediae and Merkianae, and M. micranthidifolia as a member of section Micranthes. Species proposed to be excluded from the genus Micranthes for morphological reasons were resolved in the molecular tree in Saxifraga. Many morphological characters surveyed were homoplasious to varying extents. Micromorphological characters support comparatively well the clades in the phylogenetic tree. An updated nomenclature and a taxonomic conspectus of sections and species of Micranthes are provided. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 47–66.  相似文献   

15.
Phylogenetic relationships within the magnoliid basal angiosperm genus Pseuduvaria (Annonaceae) are investigated using chloroplast DNA sequences from five regions: psbA-trnH spacer, trnL-F, matK, rbcL, and atpB-rbcL spacer. Over 4000 nucleotides from 51 species (of the total 53) were sequenced. The five cpDNA datasets were analyzed separately and in combination using maximum parsimony (MP), maximum likelihood (ML), and Bayesian methods. The phylogenetic trees constructed using all three phylogenetic methods, based on the combined data, strongly support the monophyly of Pseuduvaria following the inclusion of Craibella phuyensis. The trees generated using MP were less well resolved, but relationships are similar to those obtained using the other methods. ML and Bayesian analyses recovered trees with short branch lengths, showing five main clades. This study highlights the evolutionary changes in seven selected morphological characters (floral sex, stamen and carpel numbers, inner petal color, presence of inner petal glands, flowering peduncle length, and monocarp size). Although floral unisexuality is ancestral within the genus, several evolutionary lineages reveal reversal to bisexuality. Other phylogenetic transitions include the evolution of sapromyophily, and fruit-bat frugivory and seed dispersal, thus allowing a wide range of adaptations for species survival.  相似文献   

16.
Crambinae (2047 spp.) and Scopariinae (577 spp.) are two major groups of pyraloid moths with a worldwide distribution. Their larvae feed predominantly on Poales and Bryophyta, with many cereal crop pests. We present the first molecular phylogeny of the two groups based on five nuclear genes and one mitochondrial gene (total = 4713 bp) sampled for 58 crambine species representing 56 genera and all tribes, 33 scopariine species representing 12 genera, and species in several other crambid lineages. Maximum likelihood and Bayesian analyses of the molecular data resolve suprageneric relationships in Crambinae and Scopariinae, whereas relationships between these and other subfamilies remain ambiguous. Crambinae and Scopariinae are each recovered as monophyletic groups, and Erupini, formerly regarded as an ingroup of Midilinae, is recovered as a possible sister group of Crambinae. The tree topology suggests the following two major changes within Crambinae: Prionapterygini Landry syn.n. of Ancylolomiini Ragonot stat. rev. and Myelobiini Minet syn.n. of Chiloini Heinemann. Argyriini Munroe is monophyletic after the transfer of Pseudocatharylla Bleszynski and Vaxi Bleszynski to Calamotrophini. Crambini, Diptychophorini and Haimbachiini are monophyletic after the exclusion of Ancylolomia Hübner, Euchromius Guenée, Micrelephas Dognin and Miyakea Marumo from Crambini, as well as Microchilo Okano from Diptychophorini. Euchromiini tribe n. is described for Euchromius. Microcramboides Bleszynski syn.n. and Tortriculladia Bleszynski syn.n. are synonymized with Microcrambus Bleszynski. In Scopariinae, Caradjaina Leraut syn.n. and Cholius Guenée syn.n. are synonymized with Scoparia Haworth, and, in addition, Dasyscopa Meyrick syn.n. , Dipleurinodes Leraut syn.n. and Eudipleurina Leraut syn.n. are synonymized with Eudonia Billberg. Micraglossa melanoxantha (Turner) (Scoparia) comb.n. is proposed as a new combination. We analysed 27 morphological characters of wing venation, tympanal organs, male and female genitalia, as well as host plant data and egg‐laying behaviour. The ancestral character‐state reconstructions confirmed previous apomorphies and highlighted new apomorphies for some of the newly recovered clades. The derived, nonadhesive egg‐dropping behaviour is found to have evolved at least twice in Crambinae and is associated with the use of Pooideae as host plants. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:1A84282D‐930A‐4C32‐8340‐D681BFF27A12 .  相似文献   

17.
In order to assess the phylogenetic structure of the springtail genus Palmanura, as well as to test the monophyly of the tribe Sensillanurini (Neanuridae: Neanurinae), a data matrix of morphological (chaetotactic and other) characters of members of this group was assembled and analysed in the light of Wagner parsimony. The data matrix included all the known members of the Neotropical genus Palmanura, plus representatives of Sensillanura and Americanura. Although not all the clades obtained were highly supported by bootstrap resampling, some structures were relatively constant under different approaches. Alternative analyses (unordered and ordered character states, rescaled weighting procedure) were applied. While alternative solutions were obtained, a number of structures were shared by the results irrespective of the method used. On this basis, the results suggest that some further reassessment is required to confirm formally the monophyly of the tribe Sensillanurini. The genera Palmanura and Americanura are mutually poly/paraphyletic; we thus suggest that Palmanura should be considered as a synonym of Americanura, although some character reassessment and more varied outgroup species may be necessary before a formal generic redefinition can be proposed. Finally, a comparison of the performance of the characters under Wagner parsimony analysis indicated that differences in the characters’ retention indexes are due not to the topological (tagmal) position of the traits involved, but to character coding: the characters describing quantitative features (generally numbers of setae) generally performed worse than other types of characters under parsimony. An updated list of the known members of the Sensillanurini (Collembola: Neanuridae: Neanurinae) is presented.
© The Willi Hennig Society 2009.  相似文献   

18.
Summary We investigated seed morphology in 34 species of the genus Lysimachia and in 14 species and two subspecies of six additional genera (Anagallis, Ardisiandra, Asterolinon, Glaux, Pelletiera, Trientalis), which have been shown to be closely related to, or are placed within Lysimachia in previous molecular studies. We studied seed shape, seed coat structure, and seed coat surface patterns. Three major types of seed shape were identified: (1) sectoroid, (2) polyhedral, and (3) coarsely rugose with concave hilar area. In addition, seeds may be keeled or winged. The outer layer of the seed coat is either sponge-like and adhering only loosely to the inner seed coat or it is thin and tightly adhering to the underlying tissue. Seed surface patterns can be divided into six main types: (1) reticulate, (2) tuberculate, (3) vesiculose, (4) colliculate, (5) undulate, or (6) poroid-alveolate. Seed surface patterns are mostly congruent with molecular phylogenetic relationships. A reticulate surface pattern is diagnostic of, e.g. Lysimachia subgenera Palladia and Hawaiian Lysimachiopsis. Mapping seed characters onto a recent phylogenetic tree, reveals that they provide potentially synapomorphic character states for various subclades of Lysimachia. Salient examples include a rugose seed shape, which turns out to be synapomorphic for the clade comprising the genus Pelletiera plus Asterolinon linum-stellatum and a sponge-like outer seed coat layer, which characterizes a clade with Lysimachia vulgaris, L. thyrsiflora, and L. terrestris, with an analogue that apparently evolved in parallel in Trientalis europaea. We also discuss possible habitat factors that may have favored the independent evolution of particular seed types such as winged seeds in various lineages.  相似文献   

19.
The brush and tree lizards (Urosaurus) are a small clade of phrynosomatid lizards native to western North America. Though not as well known as their diverse sister clade, the spiny lizards (Sceloporus), some Urosaurus have nonetheless become model organisms in integrative biology. In particular, dramatic phenotypic and behavioral differences associated with specific mating strategies have been exploited to address a range of ecological and evolutionary questions. However, only two phylogenies have been proposed for the group, one of which is pre-cladistic and both based principally on morphological characters that might not provide robust support for relationships within the group. To help provide investigators working on Urosaurus with a robust phylogeny in which to frame ecological and evolutionary questions, we establish a molecular phylogeny for the group. We sampled three mitochondrial and three nuclear loci, and estimated phylogenetic relationships within Urosaurus using both maximum parsimony (MP) and Bayesian inference (BI), as well as a coalescent-based species tree approach. Finally, we used two methods of ancestral state reconstruction (ASR) to gain insight into the evolution of microhabitat preference and male display signals, traits that have been the focus of studies on Urosaurus. All reconstruction methods yield nearly the same ingroup topology that is concordant in most respects with the previous cladistic analysis of the group but with some significant differences; our data suggest the primary divergence in Urosaurus occurs between a clade endemic to the Pacific versant of Mexico and the lineages of Baja California and the southwestern US, rather than placing Urosaurus graciosus as the basal taxon and linking the Baja and Mexican endemics. We find support for a single transition to a saxicolous lifestyle within the group, and either the independent gain or loss of arboreality. The evolution of throat color patterns (i.e. dewlaps) appears complex, with multiple color morphs likely involving orange reconstructed as ancestral to the group and to most lineages, followed by a single transition to a fixed blue-throated morph in one clade. These results should provide a useful framework for additional comparative work with Urosaurus, and establish the phylogenetic context in which Urosaurus diversity arose.  相似文献   

20.
We did a phylogenetic analysis on 21 of the 23 species of Stigmatopteris, a neotropical montane genus of wet forest floors. The analysis was based on four plastid markers: rbcL, rps4-trnS, trnG-trnR, and trnL-trnF. Two of the most closely related families to the Dryopteridaceae (Didymochlaenaceae and Hypodematiaceae) and 12 dryopteroid genera were used as outgroups. Eight morphological characters were mapped on the resulting tree. Stigmatopteris was recovered as monophyletic and sister to a clade formed by polystichoid ferns such as Arachniodes, Dryopteris, and Polystichum. Synapomorphies that distinguish Stigmatopteris are 1-pinnate-pinnatifid laminae, visible punctate glands in the mesophyll, the presence of hydathodes, uniseriate cilia on the scale margins, and loss of indusia. Within the genus are two main clades. The first consists of four species characterized by pinnae long-decurrent in at least the distal third of the lamina. The second consists of the remaining 17 species in the analysis and has no known morphological synapomorphies. Nested within this second clade is a subclade of six species endemic to southeastern Brazil. Anastomosing veins, a character often used in keys to distinguish the species, evolved three times within the genus.  相似文献   

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