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1.
Monophyly of the cardueline finches (Aves: Fringillidae, Carduelinae), an assemblage of 119 species of seed-eating songbirds, has not yet been rigorously tested. To test the hypothesis of cardueline monophyly I examined 37 taxa, among them 1 or 2 representatives from 16 of the 19 cardueline-finch genera as well as 4 Hawaiian honeycreepers. Each taxon was scored for 225 morphological characters, 148 from the skeleton and 77 from the integument. Cladistic analysis of these data found the carduelines to be monophyletic, so long as the honeycreeper Telespiza cantans is considered to be cardueline; as for the other honeycreepers, they form a clade but do not group with either Telespiza or the carduelines. Both cardueline monophyly and the nonmonophyly of honeycreepers have comparatively strong support, with support for cardueline monophyly coming primarily from evolutionary modifications to the head skeleton.  相似文献   

2.
Nectarivory has evolved repeatedly in a number of unrelated bird taxa throughout the world and nectar feeding birds, regardless of their taxonomic affiliation, display convergent foraging and food processing adaptations that allow them to subsist on weak sugar solutions. However, phylogeny influences sugar type preferences of nectarivores. We investigated sugar preferences, assimilation efficiency and water flux in a Neotropical honeycreeper, the Bananaquit (Coereba flaveola; Coerebidae), a member of a radiation of tanagers and finches. Bananaquits showed no preference for nearly equicaloric (25% w/v) sucrose, glucose, fructose or glucose-fructose mixtures in pair-wise choice tests. In agreement with this lack of preference, they were equally efficient at absorbing sucrose and both hexoses. Apparent assimilation efficiency of these sugars was around 97.5%. In pair-wise tests, Bananaquits displayed a strong preference for the most concentrated sucrose solution when the lowest concentration ranged from 276 to 522 mM. Between 522 and 1120 mM sucrose solution concentrations, Bananaquits were able to adjust their volumetric food intake in order to maintain a constant energy intake. At solution concentration of 276 mM, birds could not maintain their rate of energy intake by increasing food consumption enough. We consider that at low sugar concentrations, Bananaquits faced a physiological constraint; they were unable to process food at a fast enough rate to meet their energy needs. We also explored the possibility that dilute nectars might be essential to sustain high water needs of Bananaquits by allowing them to control osmolarity of the food. Between 276 and 1120 mM sucrose solution concentrations, average amount of free water drunk by Bananaquits was independent of food concentration. They drank very little supplementary water and did not effectively dilute concentrated nectars. The evidence suggests that water bulk of dilute nectars is a burden to Bananaquits.  相似文献   

3.
The Hawaiian honeycreepers are a dramatic example of adaptive radiation but contrast with the four other songbird lineages that successfully colonized the Hawaiian archipelago and failed to undergo similar diversification. To explore the processes that produced the diversity dichotomy in this insular fauna, we compared clade age and morphological diversity between the speciose honeycreepers and the comparatively depauperate Hawaiian thrushes. Mitochondrial-DNA-based genetic distances between these Hawaiian clades and their continental sister taxa indicate that the ancestral thrush colonized the Hawaiian Islands as early as the common ancestor of the honeycreepers. This similar timing of colonization indicates that the marked difference in diversity between the Hawaiian honeycreeper and thrush clades is unlikely to result from differences in these clades' tenures within the archipelago. If time cannot explain the contrasting diversities of these taxa, then an intrinsic, clade-specific trait may have fostered the honeycreeper radiation. As the honeycreepers have diversified most dramatically in morphological characters related to resource utilization, we used principal components analyses of bill characters to compare the magnitudes of morphological variation in the ancestral clades from which the Hawaiian honeycreeper and thrush lineages are derived, the Carduelini and Turdinae respectively. Although the Carduelini share a more recent common ancestor and have a lower species diversity than the Turdinae, these finch-like relatives of the honeycreepers exhibit significantly greater variation in bill morphology than do the continental relatives of the Hawaiian thrushes. The higher magnitude of morphological variation in the non-Hawaiian Carduelini suggests that the honeycreepers fall within a clade exhibiting a generally high evolutionary flexibility in bill morphology. Accordingly, although the magnitude of bill variation among the honeycreepers is similar to that of the entire passerine radiation, this dramatic morphological radiation represents an extreme manifestation of a general clade-specific ability to evolve novel morphologies.  相似文献   

4.
Tanagers of the genus Hemispingus comprise an array of 12 recognized species of rather dull-colored tanagers restricted to Andean forests. Four of these species are polytypic, with as many as seven subspecies recognized for H. superciliaris. Taxonomic relationships within this group, and with similar-looking Basileuterus warblers, have been confusing and not well understood. We used partial DNA sequences of the mitochondrial ND2 gene and a set of morphological characters to study their phylogenetic relationships. Our molecular dataset strongly supports the monophyly of Hemispingus (including the warbler-like species and the finch-like H. rufosuperciliaris) compared to other nine-primaried oscines (Ramphocelus, Chlorospingus, Atlapetes/Buarremon, Basileuterus) and indicates either that Atlapetes/Buarremon could be tanagers or that Chlorospingus could be finches. We propose a phylogeny containing three major clades: mostly greenish eye-browed birds (trifasciatus, atropileus, auricularis, calophrys), mostly gray warbler-like birds (superciliaris, verticalis, xanthophthalmus), and mostly ochraceous birds (rufosuperciliaris and goeringi, piurae, frontalis, melanotis). The relationships among these three clades are left unresolved. We suggest species status for H. auricularis and H. piurae. Our molecular data suggest that most of the diversity in Hemispingus tanagers predates the period of marked ecoclimatic fluctuations in the upper Pleistocene.  相似文献   

5.
The monophyly and phylogeny of the adaptive radiation of Hawaiian finches (Fringillidae: Drepanidini; honeycreepers, auct.) were studied using parsimony analysis of comparative osteology, combined with Templeton (Wilcoxon signed‐ranks) tests of alternative phylogenetic hypotheses. Eighty‐four osteological characters were scored in 59 terminal taxa of drepanidines, including 24 fossil forms, and in 30 outgroup species. The optimal phylogenetic trees show considerable agreement, and some conflict, with independently derived ideas about drepanidine evolution. The monophyly of a large Hawaiian radiation was upheld, although one fossil taxon from Maui fell outside the drepanidine clade. The finch‐billed species were placed as basal drepanidine taxa, and continental cardueline finches (Carduelini) were identified as the radiation's closest outgroups. The study found anatomical as well as phylogenetic evidence that the radiation had a finch‐billed ancestor. The optimal trees identify the red‐and‐black plumage group as a clade, and suggest that the tubular tongue evolved only once in the radiation. Because comparative osteology provides too few characters to strongly support all the nodes of the tree, it was helpful to evaluate statistical support for alternative hypotheses about drepanidine relationships using the Templeton test. Among the alternatives that received significant statistical support are a relationship of the drepanidines with cardueline finches rather than with the Neotropical honeycreepers (Thraupini), classification of the controversial genera Paroreomyza and Melamprosops as drepanidines, and a secondary loss of the tubular tongue in Loxops mana. The hypothesis of monophyly for all the Hawaiian taxa in the study was not rejected statistically. The study provides a framework for incorporating morphological and palaeontological information in evolutionary studies of the Drepanidini. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 141 , 207–255.  相似文献   

6.
The native Hawaiian honeycreepers represent a classic example of adaptive radiation and speciation, but currently face one the highest extinction rates in the world. Although multiple factors have likely influenced the fate of Hawaiian birds, the relatively recent introduction of avian malaria is thought to be a major factor limiting honeycreeper distribution and abundance. We have initiated genetic analyses of class II beta chain Mhc genes in four species of honeycreepers using methods that eliminate the possibility of sequencing mosaic variants formed by cloning heteroduplexed polymerase chain reaction products. Phylogenetic analyses group the honeycreeper Mhc sequences into two distinct clusters. Variation within one cluster is high, with dN > dS and levels of diversity similar to other studies of Mhc (B system) genes in birds. The second cluster is nearly invariant and includes sequences from honeycreepers (Fringillidae), a sparrow (Emberizidae) and a blackbird (Emberizidae). This highly conserved cluster appears reminiscent of the independently segregating Rfp-Y system of genes defined in chickens. The notion that balancing selection operates at the Mhc in the honeycreepers is supported by transpecies polymorphism and strikingly high dN/dS ratios at codons putatively involved in peptide interaction. Mitochondrial DNA control region sequences were invariant in the i'iwi, but were highly variable in the 'amakihi. By contrast, levels of variability of class II beta chain Mhc sequence codons that are hypothesized to be directly involved in peptide interactions appear comparable between i'iwi and 'amakihi. In the i'iwi, natural selection may have maintained variation within the Mhc, even in the face of what appears to a genetic bottleneck.  相似文献   

7.
Avian malaria is an important cause of the decline of endemic Hawaiian honeycreepers. Because of the complexity of this disease system we used a computer model of avian malaria in forest birds to evaluate how two proposed conservation strategies: 1) reduction of habitat for mosquito larvae and 2) establishment of a low-elevation, malaria-tolerant honeycreeper (Hawaii Amakihi) to mid-elevation forests would affect native Hawaiian honeycreeper populations. We evaluated these approaches in mid-elevation forests, where malaria transmission is seasonal and control strategies are more likely to work. Our model suggests the potential benefit of larval habitat reduction depends on the level of malaria transmission, abundance of larval cavities, and the ability to substantially reduce these cavities. Permanent reduction in larval habitat of >80% may be needed to control abundance of infectious mosquitoes and benefit bird populations. Establishment of malaria-tolerant Amakihi in mid-elevation forests increases Amakihi abundance, creates a larger disease reservoir, and increases the abundance of infectious mosquitoes which may negatively impact other honeycreepers. For mid-elevation sites where bird populations are severely affected by avian malaria, malaria-tolerant Amakihi had little impact on other honeycreepers. Both management strategies may benefit native Hawaiian honeycreepers, but benefits depend on specific forest characteristics, the amount of reduction in larval habitat that can be achieved, and how malaria transmission is affected by temperature.  相似文献   

8.
Allele length variation at 16 microsatellite loci was used to estimate the phylogeny of 13 out of the 14 species of Darwin''s finches. The resulting topology was similar to previous phylogenies based on morphological and allozyme variation. An unexpected result was that genetic divergence among Galápagos Island populations of the warbler finch (Certhidea olivacea) predates the radiation of all other Darwin''s finches. This deep split is surprising in view of the relatively weak morphological differentiation among Certhidea populations and supports the hypothesis that the ancestor of all Darwin''s finches was phenotypically similar to Certhidea. The results also resolve a biogeographical problem: the Cocos Island finch evolved after the Galápagos finch radiation was under way, supporting the hypothesis that this distant island was colonized from the Galápagos Islands. Monophyletic relationships are supported for both major groups, the ground finches (Geospiza) and the tree finches (Camarhynchus and Cactospiza), although the vegetarian finch (Platyspiza crassirostris) appears to have diverged prior to the separation of ground and tree finches. These results demonstrate the use of microsatellites for reconstructing phylogenies of closely related species and interpreting their evolutionary and biogeographic histories.  相似文献   

9.
Aim We used mitochondrial DNA sequence data to reconstruct the phylogeny of a large clade of tanagers (Aves: Thraupini). We used the phylogeny of this Neotropical bird group to identify areas of vicariance, reconstruct ancestral zoogeographical areas and elevational distributions, and to investigate the correspondence of geological events to speciation events. Location The species investigated are found in 18 of the 22 zoogeographical regions of South America, Central America and the Caribbean islands; therefore, we were able to use the phylogeny to address the biogeographical history of the entire region. Methods Molecular sequence data were gathered from two mitochondrial markers (cytochrome b and ND2) and analysed using Bayesian and maximum‐likelihood approaches. Dispersal–vicariance analysis (DIVA) was used to reconstruct zoogeographical areas and elevational distributions. A Bayesian framework was also used to address changes in elevation during the evolutionary history of the group. Results Our phylogeny was similar to previous tanager phylogenies constructed using fewer species; however, we identified three genera that are not monophyletic and uncovered high levels of sequence divergence within some species. DIVA identified early diverging nodes as having a Northern Andean distribution, and the most recent common ancestor of the species included in this study occurred at high elevations. Most speciation events occurred either within highland areas or within lowland areas, with few exchanges occurring between the highlands and lowlands. The Northern Andes has been a source for lineages in other regions, with more dispersals out of this area relative to dispersals into this area. Most of the dispersals out of the Northern Andes were dispersals into the Central Andes; however, a few key dispersal events were identified out of the Andes and into other zoogeographical regions. Main conclusions The timing of diversification of these tanagers correlates well with the main uplift of the Northern Andes, with the highest rate of speciation occurring during this timeframe. Central American tanagers included in this study originated from South American lineages, and the timing of their dispersal into Central America coincides with or post‐dates the completion of the Panamanian isthmus.  相似文献   

10.
The most extensively studied group of Darwin's finches is the genus Geospiza, the ground finches, and yet little is known about the evolutionary history and genetic relationships of these birds. Studies using either allozyme or morphological data have been unable to resolve relationships between the six species and numerous populations of ground finches. In this paper we report the results of a study using mitochondrial control region and nuclear internal transcribed spacer (ITS) 1 sequence data. The differentiation of the ground finch species based on morphological data is not reflected in either mitochondrial or nuclear DNA sequence phylogenies. Furthermore, there is little concordance between the mitochondrial haplotypes and ITS alleles found within individuals. We suggest that the absence of species-specific lineages can be attributed to ongoing hybridization involving all six species of Geospiza. There are no long term selective pressures against hybridization within this genus, and therefore a genetically homogenous genus may be maintained indefinitely. Hybridization has apparently played a role in the adaptive radiation of Darwin's finches.  相似文献   

11.
To understand the origin of Pantepui montane biotas, we studied the biogeography of toucanets in the genus Aulacorhynchus. These birds are ideal for analyzing historical relationships among Neotropical montane regions, given their geographic distribution from Mexico south to Bolivia, including northern Venezuela (Cordillera de la Costa), and the Pantepui. Analyses were based on molecular phylogenies using mitochondrial and nuclear DNA sequences. Topology tests were applied to compare alternative hypotheses that may explain the current distribution of Aulacorhynchus toucanets, in the context of previous hypotheses of the origin of Pantepui montane biotas. Biogeographic reconstructions in RASP and Lagrange were used to estimate the ancestral area of the genus, and an analysis in BEAST was used to estimate a time framework for its diversification. A sister relationship between the Pantepui and Andes+Cordillera de la Costa was significantly more likely than topologies indicating other hypothesis for the origin of Pantepui populations. The Andes was inferred as the ancestral area for Aulacorhynchus, and the group has diversified since the late Miocene. The biogeographic patterns found herein, in which the Andes are the source for biotas of other regions, are consistent with those found for flowerpiercers and tanagers, and do not support the hypothesis of the geologically old Pantepui as a source of Neotropical montain diversity. Based on the high potential for cryptic speciation and isolation of Pantepui populations, we consider that phylogenetic studies of additional taxa are important from a conservation perspective.  相似文献   

12.
The tanagers (Passeriformes: Emberizidae: Thraupinae) are a diverse group of mostly Neotropical birds with a wide range of feeding morphologies, behaviors, plumage patterns and colors, and habitat preferences. Phylogenetic relationships of genera in this lineage were investigated using cytochromebsequence data. This study indicates that the generaEuphoniaandChlorophonia(traditionally considered part of Thraupinae) do not form a monophyletic group with the other tanagers. Within the rest of Thraupinae, several monophyletic groups are identified that agree with traditional sequential taxonomies. Other monophyletic groups provide novel interpretations of biogeographic patterns and morphological evolution within tanagers. In several lineages, plumage patterns and colors persist despite dramatic changes in bill morphology. Phylogenetic structure and estimated timings of divergence events indicate that tanagers probably originated on Caribbean islands and later diversified throughout Central and South America during the mid-Tertiary.  相似文献   

13.
We reanalysed Yang & Pattern's allozyme data, published in Auk in 1981, of Darwin's finches with a variety of distance and cladistic methods to estimate the phylogeny of the group. Different methods yielded different results, nevertheless there was widespread agreement among the distance methods on several groupings. First, the two species of Camarhynchus grouped near one another, but not always as a monophyletic group. Second, Cactospiza pallida and Platyspiza crassirostris formed a monophyletic group. Finally, all the methods (including parsimony) supported the monophyly of the ground finches. The three distance methods also found close relationships generally between each of two populations of Geospiza scandens, G. difficilis and G. conirostris. There is evidence for inconstancy of evolutionary rates among species. Results from distance methods allowing for rate variation among lineages suggest three conclusions which differ from Yang and Patton's findings. First, the monophyletic ground finches arose from the paraphyletic tree finches. Yang and Patton found that the ground finches and tree finches were sister monophyletic taxa. Second, Geospiza scandens appears to be a recently derived species, and not the most basal ground finch. Third, G. fuliginosa is not a recently derived species of ground finch, but was derived from an older split from the remaining ground finches. Most of these conclusions should be considered tentative both because the parsimony trees disagreed sharply with the distance trees and because no clades were strongly supported by the results of bootstrapping and statistical tests of alternative hypotheses. Absence of strong support for clades was probably due to insufficient data. Future phylogenetic studies, preferably using DNA sequence data from several unlinked loci, should sample several populations of each species, and should attempt to assess the importance of hybridization in species phylogeny.  相似文献   

14.
To test the hypothesis that migrants infected with blood parasites arrive on the northern coast of the Gulf of Mexico in poorer condition than uninfected birds, we examined 1705 migrant passerine birds representing 54 species of 11 families from 2 Gulf Coast sites for blood parasites. Three hundred and sixty (21.1%) were infected with 1 or more species of 4 genera of blood parasites. The prevalence of parasites was as follows: Haemoproteus spp. (11.7%), Plasmodium spp. (6.7%), Leucocytozoon spp. (1.3%), and Trypanosoma spp. (1.2%). Both prevalence and density of Haemoproteus spp. infection varied among species. We found no relationship of gender or age with the prevalence of Haemoproteus spp. infection or Plasmodium spp. infection, with the exception of the orchard oriole (Icterus spurius) for which older birds were more likely to be infected with Haemoproteus spp. than younger birds. We also found that scarlet tanagers and summer tanagers infected with species of Haemoproteus have lower fat scores than uninfected individuals and that rose-breasted grosbeaks and Baltimore orioles infected with Haemoproteus spp. have a smaller mean body mass than uninfected individuals. Blood parasites do seem to pose a physiological cost for Neotropical migrant passerines and may be important components of the ecology of these species.  相似文献   

15.
Neotropical tanagers known as flowerpiercers ( Diglossa and Diglossopis ) have a novel feeding adaptation, comprising a downward curved hook on the maxilla that allows these species to obtain floral nectar without pollination. Using mitochondrial DNA sequences, the phylogenetic relationships of all 18 species of flowerpiercers were studied for the first time. Strong support was found for the monophyly of flowerpiercers and for the monophyly of four superspecies within flowerpiercers. However, previously described species-groups, as well as the genus Diglossopis , are not monophyletic. The biogeographic origin of flowerpiercers was identified as Andean, with a single dispersal event from the northern Andes to Central America and a single dispersal event from the northern Andes to the tepuis. The first principal component, representing a contrast between hook size and bill size, was mapped onto the phylogeny to examine the evolution of relative hook size in the group. Across the phylogeny, a relatively large hook and a relatively small hook evolved multiple times in unrelated lineages, indicating lability in bill morphology. Differences in hook size among sympatric species, together with habitat partitioning and behavioural differences, can explain the coexistence of multiple species of flowerpiercers at the same locality.   © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 14–28.  相似文献   

16.
The Poóuli (Melamprosops phaeosoma) is a highly endangered Hawaiian honeycreeper endemic to Maui, and is currently one of the World's rarest birds. Only two wild individuals of this species are now known to exist, and they are restricted to the windward slopes of Haleakala volcano on east Maui. Studies of the more common honeycreepers on the Hawaiian islands describe a diverse array of spatial use and movement patterns, which vary according to specific ecological needs. In contrast, spatial use and movement of Poóuli are very poorly known, despite continuous field monitoring of all three individuals since 1997. We analyzed annual data by breeding season between 1995 and 2001 for three individuals, and eight days of telemetry data derived from the radio-tracking of one individual in 2002, using GIS and conventional methods, to estimate home range size, and to interpret these data alongside those for other honeycreepers. We estimated mean home range sizes of 8.43 hectares (ha) from annual re-sights using kernel analysis and 2.14 ha using minimum convex polygons, and 8.44 and 3.51 ha respectively from telemetry data. Our estimates conform to those derived for other insectivorous honeycreepers, but indicate that Poóuli may forage widely to support their diet of forest snails. Our home range size estimates are compatible with estimates of population density for Poóuli that were derived from field transects between 1975 and 1985, suggesting that such field methods may be a reliable density estimator for rare forest birds. Jim J. Groombridge and Bill Sparklin: Joint first author  相似文献   

17.
The phylogeny of swallows was reconstructed by comparing segments of three genes, nuclear beta-fibrinogen intron 7 (betafib7), mitochondrial cytochrome b (cytb), and mitochondrial ND2, in a variety of combinations using maximum likelihood and Bayesian methods. betafib7 was sequenced for 47 species, cytb for 74 species, and ND2 for 61 species to yield comparisons among 75 of the 84 currently recognized swallow species. The family Hirundinidae was confirmed to consist of two clades, Pseudochelidoninae (river martins) and Hirundininae (typical swallows). The Hirundininae is further divided into mud nesters (Hirundo sensu lato), core martins (Phedina, Riparia, and New World endemic genera), and basal relicts (Psalidoprocne, Cheramoeca, and Pseudhirundo). We did not resolve the hierarchy among these three hirundinine groups, but discovered many relationships within them. Mud-nesting genera have the following relationships: (Hirundo sensu stricto, Ptyonoprogne), (Delichon, (Petrochelidon, Cecropis)). Core martins have the following topology: (Phedina, Riparia cincta), (Riparia sensu stricto, Tachycineta, ((Stelgidopteryx, Progne), (Neotropical endemic genera))). Interspecific relationships among the Neotropical endemics were resolved completely; Atticora and Notiochelidon are paraphyletic, and all Neotropical endemics probably should be lumped into one or two genera. The final group of hirundinines, the basal relicts, consists of a sister pair, the Australian Cheramoeca and African Pseudhirundo. The African saw-wings (Psalidoprocne) are their likely sister group.  相似文献   

18.
Phylogenetic relationships among the true finches (Fringillidae) have been confounded by the recurrence of similar plumage patterns and use of similar feeding niches. Using a dense taxon sampling and a combination of nuclear and mitochondrial sequences we reconstructed a well resolved and strongly supported phylogenetic hypothesis for this family. We identified three well supported, subfamily level clades: the Holoarctic genus Fringilla (subfamly Fringillinae), the Neotropical Euphonia and Chlorophonia (subfamily Euphoniinae), and the more widespread subfamily Carduelinae for the remaining taxa. Although usually separated in a different family-group taxon (Drepanidinae), the Hawaiian honeycreepers are deeply nested within the Carduelinae and sister to a group of Asian Carpodacus. Other new relationships recovered by this analysis include the placement of the extinct Chaunoproctus ferreorostris as sister to some Asian Carpodacus, a clade combining greenfinches (Carduelis chloris and allies), Rhodospiza and Rhynchostruthus, and a well-supported clade with the aberrant Callacanthis and Pyrrhoplectes together with Carpodacus rubescens. Although part of the large Carduelis-Serinus complex, the poorly known Serinus estherae forms a distinct lineage without close relatives. The traditionally delimited genera Carduelis, Serinus, Carpodacus, Pinicola and Euphonia are polyphyletic or paraphyletic. Based on our results we propose a revised generic classification of finches and describe a new monotypic genus for Carpodacus rubescens.  相似文献   

19.
The systematic relationships of acanthocephalans, including Leptorhynchoides and Pseudoleptorhynchoides that occur in freshwater and marine fishes in Neartic and Neotropical regions, are enigmatic. Leptorhynchoides (3 species) and Pseudoleptorhynchoides (1 species) are presently classified in the Rhadinorhynchidae. However, recent molecular and morphological phylogenies have challenged the monophyly of this family. Sequences of nuclear ribosomal DNA (large subunit, small subunit regions) and the mitochondrial cytochrome c oxidase subunit I gene of Leptorhynchoides thecatus and Pseudoleptorhynchoides lamothei were used in phylogenetic analyses with available sequences of 26 other acanthocephalans. Maximum parsimony and maximum likelihood analyses were identical in placing both genera in the Illiosentidae. Bootstrap analyses also indicate that placement of these genera with members of Illiosentidae is reliably supported.  相似文献   

20.
A mitochondrial DNA (mtDNA) phylogeny of cichlid fish is presented for the most taxonomically inclusive data set compiled to date (64 taxa). 16S rDNA data establish with confidence relationships among major lineages of cichlids, with a general pattern congruent with previous morphological studies and less inclusive molecular phylogenies based on nuclear genes. Cichlids from Madagascar and India are the most basal groups of the family Cichlidae and sister to African–Neotropical cichlids. The cichlid phylogeny suggests drift-vicariance events, consistent with the fragmentation of Gondwana, to explain current biogeographic distributions. Important phylogenetic findings include the placement of the controversial genus Heterochromis basal among African cichlids, the South American genus Retroculus as the most basal taxon of the Neotropical cichlid assemblage, and the close relationship of the Neotropical genera Cichla with Astronotus rather than with the crenicichlines. Based on a large number of South American genera, the Neotropical cichlids are defined as a monophyletic assemblage and shown to harbor significantly higher levels of genetic variation than their African counterparts. Relative rate tests suggest that Neotropical cichlids have experienced accelerated rates of molecular evolution. But these high evolutionary rates were significantly higher among geophagine cichlids. Received: 18 September 1998 / Accepted: 16 December 1998  相似文献   

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