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1.
Phylogenetic relationships in a group of 21 African rodent species designated as the Praomys group (Murinae) were investigated using morphological characters and sequence data from the complete mitochondrial cytochrome b gene and nuclear IRBP gene fragment (840bp). The molecular results confirm the monophyly of the Praomys group, including the species Malacomys verschureni, while the other Malacomys species appear very divergent. The basal relationships within the Praomys group are poorly resolved, suggesting a rapid radiation at about 7-9 million years ago based on genetic divergence rates calibrated from the fossil record. Discrepancies between molecular and morphological results probably reflect of numerous convergences as well as variations in the rates of morphological evolution among lineages. Reconstructions of the ancestral character states suggest a savannah origin for the Praomys group, along with some morphological traits conserved by stasis in savannah taxa. At the same time, forest taxa seem to be characterized by an accelerated morphological evolution, with acquisition of convergent adaptive characters.  相似文献   

2.
The 3400 species of Eumolpinae constitute one of the largest subfamilies of leaf beetles (Chrysomelidae). Their systematics is still largely based on late 19th century monographs and remains highly unsatisfactory. Only recently, some plesiomorphic lineages have been split out as separate subfamilies, including the southern hemisphere Spilopyrinae and the ambiguously placed Synetinae. Here we provide insight into the internal systematics of the Eumolpinae based on molecular phylogenetic analyses of three ribosomal genes, including partial mitochondrial 16S and nuclear 28S and complete nuclear 18S rRNA gene sequences. Sixteen morphological characters considered important in the higher-level systematics of Eumolpinae were also included in a combined analysis with the molecular characters. All phylogenetic analyses were performed using parsimony by optimizing length variation directly on the tree, as implemented in the POY software. The data support the monophyly of the Spilopyrinae outside the clade including all sampled Eumolpinae, corroborating their treatment as a separate subfamily within the Chrysomelidae. The systematic placement of the Synetinae remains ambiguous but consistent with considering it a different subfamily as well, since the phylogenetic analyses using all the available evidence show the representative sequence of the subfamily also unrelated to the Eumolpinae. The Megascelini, traditionally considered a separate subfamily, falls within the Eumolpinae. Several recognized taxonomic groupings within Eumolpinae, including the tribes Adoxini or Typophorini, are not confirmed by molecular data; others like Eumolpini seem well supported. Among the morphological characters analyzed, the presence of a characteristic groove on the pygidium (a synapomorphy of the Eumolpini) and the shape of tarsal claws (simple, appendiculate or bifid) stand out as potentially useful characters for taxonomic classification in the Eumolpinae.  相似文献   

3.
Abstract. The Dolichopodidae is a species‐rich dipteran group with almost 7000 described species. The monophyly of the subfamilies and their relationships remain largely unknown because the polarities of key morphological characters are unclear and molecular data are available only for 9 of the 19 proposed subfamilies. Here we test whether molecular data from two nuclear (18S, 28S) and four mitochondrial (12S, 16S, Cytb, COI) genes can resolve the higher‐level relationships within the family. Our study is based on 76 Oriental species from 12 dolichopodid subfamilies and uses eight species of Empididae and Hybotidae as outgroups. Parsimony and likelihood analyses confirm the monophyly of the Dolichopodidae, as well as the monophyly of five of the ten subfamilies represented by more than two species [Sympycninae, Sciapodinae, Dolichopodinae, Hydrophorinae (excluding tribe Aphrosylini), Neurigoninae]. There is strong support for restoring the tribe Aphrosylini as a separate subfamily Aphrosylinae. The monophyly of Medeterinae, Peloropeodinae and Diaphorinae is dependent on which tree reconstruction technique is used, how indels are coded, and whether the fast‐evolving sites are excluded. Overall, we find that our sample of Oriental species is largely compatible with the subfamily concepts that were developed for the northern temperate fauna. However, our data provide little support for relationships between the subfamilies. Branch lengths, saturation, and distance plots suggest that this is probably the result of the rapid origin of dolichopodid subfamilies over a relatively short time. We find that genera that are difficult to place into subfamilies based on morphological characters are generally also difficult to place using molecular data. We predict that a dense, balanced taxon sample and protein‐encoding nuclear genes will be needed to resolve the higher‐level relationships in the Dolichopodidae.  相似文献   

4.
We evaluated the boundaries among Nymphoides (Menyanthaceae) species in Africa, a region where the genus has received relatively little attention. We gathered morphological data from seeds using light and scanning electron microscopy, and we conducted molecular phylogenetic analyses using nuclear sequence data from the internal transcribed spacer (ITS) region. Morphological and molecular features distinguished six species and affirmed their respective geographic ranges. No African specimens were attributable to Nymphoides indica, even though this paleotropical species previously had been understood to grow in Africa. We establish the new combination Nymphoides senegalensis (G. Don) Tippery, based on an established African basionym, to accommodate the specimens formerly identified as N. indica. Phylogenetic analyses resolved two distinct clades containing African species. The majority of African species are closely related to neotropical species, with which they share similar petal ornamentation. The morphologically distinct N. ezannoi shares floral and phylogenetic similarity with species from North America and Asia. Results presented here support prior hypotheses that allopolyploid species in the Americas may have originated from one or more parental lineages in Africa. Seed morphological characters remain some of the most reliable features for identifying species, particularly for herbarium specimens lacking observable floral characters.  相似文献   

5.
Phylogenetic relationships among 26 South African species in the tribe Aphnaeini (Lepidoptera: Lycaenidae) were inferred from DNA characters of the mitochondrial gene cytochrome oxidase I (COI), using maximum-parsimony methods. The resulting phylogenetic estimate supports the systematic hypothesis made by Heath (1997, Metamorphosis, supplement 2), based on morphological characters, that at least three preexisting genera (Chrysoritis, Poecilmitis, and Oxychaeta) should be collapsed into the single monophyletic genus Chrysoritis. Two of the species groups described by Heath within Chrysoritis are also monophyletic, while one is paraphyletic and thus unsupported by the molecular data. Strong node support and skewed transition/transversion ratios suggest that two Chrysoritis clades contain synonymous species. Aphytophagy appears as a derived feeding strategy. Evolutionary patterns of ant association indicate lability at the level of ant genus, while association with different ant subfamilies may have played an ancestral and chemically mediated role in the diversification of South African aphnaeines.  相似文献   

6.
Recently, the phylogenetic placement of the African slender snouted crocodile, Crocodylus cataphractus, has come under scrutiny and herein we address this issue using molecular and morphological techniques. Although it is often recognized as being a "basal" form, morphological studies have traditionally placed C. cataphractus within the genus Crocodylus, while molecular studies have suggested that C. cataphractus is very distinct from other Crocodylus. To address the relationship of this species to its congeners we have sequenced portions of two nuclear genes (C-mos 302bp and ODC 294bp), and two mitochondrial genes (ND6-tRNA(glu)-cytB 347bp and control region 457bp). Analyses of these molecular datasets, both as individual gene sequences and as concatenated sequences, support the hypothesis that C. cataphractus is not a member of Crocodylus or Osteolaemus. Examination of 165 morphological characters supports and strengthens our resurrection of an historic genus, Mecistops (Gray 1844) for cataphractus.  相似文献   

7.
The phylogeny of spider flies is presented based on an analysis of DNA sequence data combined with morphological characters for both living and fossil species. We sampled 40 extant and extinct genera across all major lineages of Acroceridae, which were compared with outgroup taxa from various lower brachyceran families. In all, 81 morphological characters of 60 extant and 10 extinct ingroup species were combined with 7.1 kb of DNA sequences of two nuclear (CAD and 28S rDNA) and two mitochondrial genes (COI and 16S rDNA). Results strongly support the monophyly of Acroceridae, with major clades contained within classified here in five extant subfamilies (Acrocerinae, Cyrtinae stat. rev. , Ogcodinae stat. rev. , Panopinae and Philopotinae) and one extinct subfamily, Archocyrtinae. The evolution of important spider fly traits is discussed, including genitalia and wing venation. The status of the enigmatic Psilodera Gray and Pterodontia Gray as members of the Panopinae is confirmed based on both molecular and morphological data.  相似文献   

8.
Although Antarctic teleosts of the suborder Notothenioidei are well studied, the status of some families remains unclear because of limited taxonomic sampling and sometimes poor statistical support from molecular phylogenies. It is true for the Bathydraconidae, the sister-family of the famous haemoglobin-less icefishes, the Channichthyidae. The present study is aimed at clarifying bathydraconid phylogeny and the interrelationships of higher notothenioid families, taking nototheniids as the outgroup. For this purpose, about 300 positions in the mitochondrial control region, 750 positions in the cytochrome b, and a matrix of morphological characters were employed for separate and simultaneous phylogenetic analyses. We conclude that (1) molecular data strongly support the split of bathydraconids into three clades, here called the Bathydraconinae (Bathydraco, Prionodraco, Racovitzia), the Gymnodraconinae (Gymnodraco, Psilodraco, Acanthodraco), and the Cygnodraconinae (Cygnodraco, Gerlachea, Parachaenichthys). Interrelationships between these three and the Channichthyidae remain unclear. Molecular data support neither paraphyly nor monophyly of the bathydraconids, while morphology leads to the monophyly of the family based on the synapomorphic loss of the spinous dorsal fin; (2) The Channichthyidae, the Harpagiferidae, and the Artedidraconidae are monophyletic families; (3) the phylogeny of the haemoglobin-less channichthyids is completely resolved and congruent with the conclusions of based on anatomical characters; (4) The present molecular results as well as other molecular studies favour the hypothesis that harpagiferids are the sister-group of artedidraconids, though our morphological matrix puts harpagiferids as the sister-group of all other families on the basis of a single character. With regard to harpagiferid relationships, it is interesting to notice that, when analysed simultaneously, morphological characters are not automatically "swamped" within molecular ones: in the tree based on the simultaneous analysis of all available data, morphological characters impose their topology on molecules.  相似文献   

9.
Sciomyzidae is a family of acalyptrate flies with 546 species in 61 genera that is among the most extensively studied groups of higher Diptera. Most of the known larvae are obligate enemies of Gastropoda. Hundreds of studies published over the past 50 years have resulted in detailed information concerning morphology of adults and immature stages, biology, development, behaviour, phenology and distribution. However, studies of phylogenetic relationships are based almost exclusively on morphological characters of adults, and no comprehensive molecular analysis across the family has been published. Here we fill this void by generating and analysing molecular data for 54 species of Sciomyzidae (22 genera), including Phaeomyiidae (one genus), and seven representative species of five other families of Sciomyzoidea (Coelopidae, Dryomyzidae, Helcomyzidae, Heteromyzidae and Huttoninidae) as outgroups. The reconstruction is based on morphological characters as well as nucleotide sequences for genes from the mitochondrial (12S, 16S, COI, COII, Cytb) and nuclear genome (28S, EF1α). The results are compared with recent morphological analyses. Our analyses support the monophyly of Sciomyzidae + Phaeomyiidae, and place Phaeomyiinae as a unique lineage within Sciomyzidae. A modified classification comprising three subfamilies is proposed. The major subfamily, Sciomyzinae, consists of two monophyletic and well separated groups, the tribes Sciomyzini and Tetanocerini.  相似文献   

10.
Family level molecular phylogenetic analyses of cichlid fishes have generally suffered from a limited number of characters and/or poor taxonomic sampling across one or more major geographic assemblage, and therefore have not provided a robust test of early intrafamilial diversification. Herein we use both nuclear and mitochondrial nucleotide characters and direct optimization to reconstruct a phylogeny for cichlid fishes. Representatives of major cichlid lineages across all geographic assemblages are included, as well as nearly twice the number of characters as any prior family‐level study. In a strict consensus of 81 equally most‐parsimonious hypotheses, based on the simultaneous analysis of 2222 aligned nucleotide characters from two mitochondrial and two nuclear genes, four major subfamilial lineages are recovered with strong support. Etroplinae, endemic to Madagascar (Paretroplus) and southern Asia (Etroplus), is recovered as the sister taxon to the remainder of Cichlidae. Although the South Asian cichlids are monophyletic, the Malagasy plus South Asian lineages are not. The remaining Malagasy lineage, Ptychochrominae, is monophyletic and is recovered as the sister group to a clade comprising the African and Neotropical cichlids. The African (Pseudocrenilabrinae) and Neotropical (Cichlinae) lineages are each monophyletic in this reconstruction. The use of multiple molecular markers, from both mitochondrial and nuclear genes, results in a phylogeny that in general exhibits strong support, notably for early diversification events within Cichlidae. Results further indicate that Labroidei is not monophyletic, and that the sister group to Cichlidae may comprise a large and diverse assemblage of percomorph lineages. This hypothesis may at least partly explain why morphological studies that have attempted to place Cichlidae within Percomorpha, or that have tested cichlid monophyly using only “labroid” lineages, have met with only limited success. © The Willi Hennig Society 2004.  相似文献   

11.
Our understanding of how fast mating behaviour evolves in insects is rather poor due to a lack of comparative studies among insect groups for which phylogenetic relationships are known. Here, we present a detailed study of the mating behaviour of 27 species of Sepsidae (Diptera) for which a well‐resolved and supported phylogeny is available. We demonstrate that mating behaviour is extremely diverse in sepsids with each species having its own mating profile. We define 32 behavioural characters and document them with video clips. Based on sister species comparisons, we provide several examples where mating behaviour evolves faster than all sexually dimorphic morphological traits. Mapping the behaviours onto the molecular tree reveals much homoplasy, comparable to that observed for third positions of mitochondrial protein‐encoding genes. A partitioned Bremer support (PBS) analysis reveals conflict between the molecular and behavioural data, but behavioural characters have higher PBS values per parsimony‐informative character than DNA sequence characters.  相似文献   

12.
Abstract. Because the taxonomy of marine sponges is based primarily on morphological characters that can display a high degree of phenotypic plasticity, current classifications may not always reflect evolutionary relationships. To assess phylogenetic relationships among sponges in the order Verongida, we examined 11 verongid species, representing six genera and four families. We compared the utility of morphological and molecular data in verongid sponge systematics by comparing a phylogeny constructed from a morphological character matrix with a phylogeny based on nuclear ribosomal DNA sequences. The morphological phylogeny was not well resolved below the ordinal level, likely hindered by the paucity of characters available for analysis, and the potential plasticity of these characters. The molecular phylogeny was well resolved and robust from the ordinal to the species level. We also examined the morphology of spongin fibers to assess their reliability in verongid sponge taxonomy. Fiber diameter and pith content were highly variable within and among species. Despite this variability, spongin fiber comparisons were useful at lower taxonomic levels (i.e., among congeneric species); however, these characters are potentially homoplasic at higher taxonomic levels (i.e., between families). Our molecular data provide good support for the current classification of verongid sponges, but suggest a re-examination and potential reclassification of the genera Aiolochroia and Pseudoceratina . The placements of these genera highlight two current issues in morphology-based sponge taxonomy: intermediate character states and undetermined character polarity.  相似文献   

13.
Characters of the newly discovered larvae of the South African Cliff Water Beetle Aspidytes niobe were examined and integrated into a data matrix including all families of Dytiscoidea as well as Haliplidae. Fifty-three morphological characters of adults and larvae were analysed separately and combined with molecular data from six nuclear and mitochondrial genes. The phylogeny of the group is reconstructed for the study of the evolution of swimming behaviour and larval feeding habits, as well as the shift in diversification rates leading to the two most speciose lineages. The parsimony analysis of all equally weighted morphological and molecular characters combined resulted in a single well supported tree with the topology (Noteridae (Hygrobiidae ((Aspidytidae, Amphizoidae) Dytiscidae))), in agreement with the molecular data alone, but in contradiction to the morphological data, which favoured a topology in which Hygrobiidae is sister to Dytiscidae. The exclusion of third codon positions of the three protein coding genes resulted in a topology identical to that obtained with the morphological data alone, but the use of Bayesian probabilities or the amino acid sequence resulted in the same topology as that of the tree obtained with parsimony using all equally weighted characters. We concluded that interactions of third codon positions with the other data are complex, and their removal is not justified. There was a significant increase in the diversification rate at the base of the richest families (Noteridae and Dytiscidae), which could be associated with the development of simultaneous stroke and higher swimming performance, although data on the swimming behaviour of some basal groups of Noteridae are incomplete. The presence of larval mandibular sucking channels may have contributed to the diversification of Dytiscidae and the species-rich noterid genera Hydrocanthus and Canthydrus .  相似文献   

14.
Phylogenetic relationships among the nine spiral-horn antelope species of the African bovid tribe Tragelaphini are controversial. In particular, mitochondrial DNA sequencing studies are not congruent with previous morphological investigations. To test the utility of nuclear DNA intron markers at lower taxonomic levels and to provide additional data pertinent to tragelaphid evolution, we sequenced four nuclear DNA segments (MGF, PRKCI, SPTBN, and THY) and combined these data with mitochondrial DNA sequences from three genes (cytochrome b, 12S rRNA, and 16S rRNA). Our molecular supermatrix comprised 4682 characters which were analyzed independently and in combination. Parsimony and model based phylogenetic analyses of the combined nuclear DNA data are congruent with those derived from the analysis of mitochondrial gene sequences. The corroboration between nuclear and mtDNA gene trees reject the possibility that genetic processes such as lineage sorting, gene duplication/deletion and hybrid speciation account for the conflict evident in the previously published phylogenies. It suggests rather that the morphological characters used to delimit the Tragelaphid species are subject to convergent evolution. Divergence times among species, calculated using a relaxed Bayesian molecular clock, are consistent with hypotheses proposing that climatic oscillations and their impact on habitats were the major forces driving speciation in the tribe Tragelaphini.  相似文献   

15.
16.
A cladistic analysis of sequences from the chloroplast gene rbcL was used to determine the systematic affinities of Rhizophoraceae and Anisophylleaceae. This analysis rejects close relationships of Rhizophoraceae with Celastraceae or Elaeocarpaceae, suggested previously, and identifies Erythroxylaceae as sister group within the Malpighiales, supported by several morphological and anatomical characters. Our molecular results also indicate that Anisophylleaceae are nested within Cucurbitales. Although this placement is novel, this affinity is also well supported by shared morphological characters. Tribal and generic relationships within Rhizophoraceae are evaluated with a combination of six molecular data sets (rbcL, atpB-rbcL intergenic spacer, trnL-trnF intergenic spacer, ITS1, ITS2, and 5.8S) and a morphological data set. These relationships are compared with results from previous morphological cladistic analyses. Against the background of the molecular results, we briefly discuss the evolution of morphological characters traditionally used for tribal subdivision as well as characters presumably significant for adaptation to mangrove habitats, namely, aerial stilt roots and vivipary.  相似文献   

17.
The satyrine butterfly subtribe Mycalesina has undergone one of the more spectacular evolutionary radiations of butterflies in the Old World tropics. Perhaps the most phenotypically pronounced diversification of the group has occurred in the Malagasy region, where 68 currently recognized species are divided among five genera. Here, we report the results of phylogenetic analyses of sequence data from the cytochrome c oxidase II and cytochrome b mitochondrial genes, for a total of 54 mycalesine taxa, mostly from Madagascar. These molecular data complement an existing data set based on male morphological characters. The molecular results support the suggestion from morphology that three of the five Malagasy genera are paraphyletic and support the monophyly of at least three major morphological clades. Novel hypotheses of terminal taxon pairs are generated by the molecular data. Dense taxon sampling appears to be crucial for elucidating phylogenetic relationships within this large radiation. A potentially complex scenario for the origin of Malagasy mycalesines is proposed.  相似文献   

18.
We investigated the phylogenetic relationships among the three presently recognized subspecies of the tadpole shrimp, Triops cancriformis , using mitochondrial 16S and 12S rDNA sequences. Our results indicate that the taxon is divided into two distinct lineages. One lineage is formed of T. c. cancriformis populations and samples from northern Spain that had been classified as T. c. simplex in the most recent literature. The second lineage comprises all populations of T. c. mauritanicus and northern African populations of T. c. simplex . These two main lineages separated 2.3 to 8.9 million years ago, based on the range of inferred molecular clocks recognized for crustacean mtDNA sequence divergence. Percentages of divergence are in the range reported for recognized species in other notostracan lineages and we therefore propose to recognize them as two species, Triops cancriformis and Triops mauritanicus . The latter would comprise two subspecies in northern Africa, one consisting of the Moroccan populations of the former T. c. mauritanicus , the other comprising the African populations of the former T. c. simplex . It also includes three as-yet unnamed lineages. A comparison of morphological characters with the molecular data revealed that the former T. c. simplex cannot be reliably separated from T. c. cancriformis , using morphological characters that have hitherto been used to distinguish among subspecies of T. cancriformis . Our investigation is the first to demonstrate the presence of T. c. cancriformis in Africa (Tunisia). The genetic haplotypes of these populations are identical with haplotypes also occurring in Central and Western Europe, as well as in Sicily. Therefore, we hypothesize that the African populations of T. c. cancriformis represent a result of repeated long-distance dispersal across the Mediterranean Sea.  相似文献   

19.
The taxonomy of the African dwarf crocodile (genus Osteolaemus) has been disputed since a novel morphotype was discovered in the early 20th Century. Because this poorly-known reptile is widely hunted throughout the forests of Central and West Africa, resolving the existence and extent of taxonomic units has important management and conservation implications. Lack of molecular data from individuals of known origin and historical disagreement on diagnostic morphological characters have hindered attempts to settle one of the most important taxonomic questions in the Crocodylia. In an effort to clarify the evolutionary relationships among dwarf crocodiles, we sequenced three mitochondrial and two nuclear genes using a large sample of dwarf crocodiles from known localities across major drainage basins of forested Africa. Concordant results from Bayesian, maximum likelihood, maximum parsimony and population aggregation analytical methods support a previously recognized division of the dwarf crocodile into a Congo Basin form (O. osborni) and a West African form (Osteolaemus tetraspis), but also reveal a third diagnosable lineage from West Africa warranting recognition as an separate taxonomic unit. Corrected genetic distances between geographic regions ranged from 0.2% to 0.6% in nuclear fragments and 10.0 to 16.2% in mitochondrial COI. Population aggregation, using fixed and alternate character (nucleotide) states to cluster or divide populations, recovered 232 such molecular characters in 4286 bp of sequence data and unambiguously aggregated populations into their respective geographic clade. Several previously recognized morphological differences coincide with our molecular analysis to distinguish Congo Basin crocodiles from the Ogooué Basin and West Africa. Discrete morphological characters have not yet been documented between the latter two regions, suggesting further work is needed or molecular data may be required to recognize taxonomic divisions in cases where putative species are morphologically cryptic. This study highlights the importance of using widespread taxon sampling and a multiple evidence approach to diagnose species boundaries and reveal cryptic diversity.  相似文献   

20.
Combined analyses of morphological and molecular data were used to resolve phylogenetic relationships within Macrobiotidae (Eutardigrada). Morphological data were analysed using a cladistic approach with a matrix comprising 15 taxa with 17 characters to obtain a phylogenetic reconstruction. Molecular data were obtained by sequencing the cytochrome c oxidase subunit I gene in seven species of Macrobiotidae and one of Eohypsibiidae (used as outgroup). The morphological character defining the family, symmetrical claw on each leg, turns out to be plesiomorphic. Moreover, neither morphological nor molecular analyses supports a monophyletic clade for the subfamily Macrobiotinae, whereas both support a well defined evolutionary line (Murrayinae) within the family. We propose elevating the latter to family level (Murrayidae) while temporarily retaining as valid the family Macrobiotidae (amending its diagnosis, including within it only Macrobiotinae). Murrayidae opens an interesting evolutionary prospective, because the entire line has differentiated without sexual reproduction, constituting an example of evolution of asexual lineages.  相似文献   

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