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1.
The dobsonfly genus Neoneuromus van der Weele is endemic to the Oriental region. Species possess highly variable body and wing colouration and markings, not only among species but also among conspecific individuals of certain species. This stark polymorphism hinders accurate species identification, and obscures an undocumented species diversity as well as our understanding of the evolutionary history of this genus. We used multiple methods of molecular identification combined with morphological evidence to delimitate species, circumscribing a total of 13 species in Neoneuromus . Five new species are herein described: Neoneuromus indistinctus Liu, Hayashi & Yang, sp.n. , Neoneuromus maculatus Liu, Hayashi & Yang, sp.n. , Neoneuromus niger Liu, Hayashi & Yang, sp.n. , Neoneuromus similis Liu, Hayashi & Yang, sp.n. and Neoneuromus vanderweelei Liu, Hayashi & Yang, sp.n. The dated phylogeny with reconstructed ancestral areas indicates an initial divergence of Neoneuromus during the mid‐Eocene. A broad area including northeastern India and northern Indochina could be a centre for early divergence of the genus, while complex dispersal and vicariance events dating from the late Eocene to the Pliocene probably shaped the present diversity and distribution of the genus. Our ancestral character state reconstruction suggests that the pale and dark colour forms among different species, or conspecifics, could evolve rapidly and that changes in colouration could be driven by species‐specific mate recognition.  相似文献   

2.
Chauliodinae (fishflies), with their low capacity of long‐distance dispersal represent a suitable model insect group to investigate the biogeographical history. The genus Parachauliodes van der Weele, including the herein synonymized genus Sinochauliodes Liu & Yang, is endemic to East Asia. Here, we reconstruct the interspecific phylogeny of Parachauliodes based on mitochondrial DNA sequence data. Sinochauliodes syn.n. was recovered with a group of Parachauliodes species and not the sister group; we therefore treat it as the junior synonym of Parachauliodes. Species delimitation was performed combining the molecular identification with morphological evidence, with Parachauliodes inopinatus syn.n. treated as the junior synonym of Parachauliodes asahinai. The spatio‐temporal divergence pattern of Parachauliodes indicates that the genus might have originated from Eurasian continent no later than the early Miocene and the initial divergence within genus was likely to be correlated to the split of southwestern Japanese Islands from the continent. There likely was a southward dispersal in the Parachauliodes japonicus clade from southwestern Japan via the Ryukyus to Taiwan by the end of the Miocene. The present species diversity of the insular lineage of Parachauliodes was possibly shaped by island isolations and sympatric distribution.  相似文献   

3.
Phylogenetic analysis of the genus Euscorpius (Scorpiones: Euscorpiidae) across the Mediterranean region (86 specimens, 77 localities, four DNA markers: 16S rDNA, COI, COII, and ITS1), focusing on Greek fauna, revealed high variation, deep clade divergences, many cryptic lineages, paraphyly at subgenus level, and sympatry of several new and formerly known lineages. Numerous specimens from mainland and insular Greece, undoubtedly the least studied region of the genus' distribution, have been included. The reconstructed phylogeny covers representative taxa and populations across the entire genus of Euscorpius. The deepest clades detected within Euscorpius correspond (partially) to its current subgeneric division, outlining subgenera Tetratrichobothrius and Alpiscorpius. The rest of the genus falls into several clades, including subgenus Polytrichobothrius and a paraphyletic subgenus Euscorpius s.s. Several cryptic lineages are recovered, especially on the islands. The inadequacy of the morphological characters used in the taxonomy of the genus to delineate species is discussed. Finally, the time frame of differentiation of Euscorpius in the study region is estimated and the distributional patterns of the lineages are contrasted with those of other highly diversified invertebrate genera occurring in the study region. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 728–748.  相似文献   

4.
Aims Insular Southeast Asia and adjacent regions are geographically complex, and were dramatically affected by both Pliocene and Pleistocene changes in climate, sea level and geology. These circumstances allow the testing of several biogeographical hypotheses regarding species distribution patterns and phylogeny. Avian species in this area present a challenge to biogeographers, as many are less hindered by barriers that may block the movements of other species. Widely distributed Southeast Asian avian lineages, of which there are many, have been generally neglected. Ficedula flycatchers are distributed across Eurasia, but are most diverse within southern Asia and Southeast Asian and Indo‐Australian islands. We tested the roles of vicariance, dispersal and the evolution of migratory behaviours as mechanisms of speciation within the Ficedula flycatchers, with a focus on species distributed in insular Southeast Asia. Methods Using a published molecular phylogeny of Ficedula flycatchers, we reconstructed ancestral geographical areas using dispersal vicariance analysis, weighted ancestral area analysis, and a maximum likelihood method. We evaluated the evolution of migratory behaviours using maximum likelihood ancestral character state reconstruction. Speciation timing estimates were calculated via local molecular clock methods. Results Ficedula originated in southern mainland Asia, c. 6.5 Ma. Our analyses indicate that two lineages within Ficedula independently and contemporaneously colonized insular Southeast Asia and Indo‐Australia, c. 5 Ma. The potential impact of vicariance due to rising sea levels is difficult to assess in these early colonization events because the ancestral areas to these clades are reconstructed as oceanic islands. Within each of these clades, inter‐island dispersal was critical to species’ diversification across oceanic and continental islands. Furthermore, Pliocene and Pleistocene climatic change may have caused the disjunct island distributions between several pairs of sister taxa. Both vicariance and dispersal shaped the distributions of continental species. Main conclusions This study presents the first evaluation, for Ficedula, of the importance of vicariance and dispersal in shaping distributions, particularly across insular Southeast Asia and Indo‐Australia. Although vicariant speciation may have initially separated the island clades from mainland ancestors, speciation within these clades was driven primarily by dispersal. Our results contribute to the emerging body of literature concluding that dynamic geological processes and climatic change throughout the Pliocene and Pleistocene have been important factors in faunal diversification across continental and oceanic islands.  相似文献   

5.
A new scheme of the phylogeny of the tribe Arctiini is proposed. The Western Mediterranean genus Atlantarctia is considered the most primitive one in the tribe; the rest of genera form two large clades Arctia-Pericallia and Gonerda-Platyprepia. The first clade is supposed to have been subjected to radiation in western Eurasia, and the second clade, in Asia and North America in the Palaeogene when the eastern part of Asia was isolated from western Eurasia. Subsequently, most probably in the Neogene-Pleistocene, representatives of both clades spread over the whole Eurasia and North America. The Arctiini fauna of the tundra zone, which includes the genera Acerbia and Pararctia, was formed in Asia and North America, whereas the subboreal fauna (both steppe and nemoral) originated in western Eurasia. The boreal genus Borearctia has most likely also originated in Asia.  相似文献   

6.
We describe a divergent clade and three new rupicolous species of dwarf geckos of the genus Cnemaspis from the Mysore Plateau, southern India. Cnemaspis bangarasp. nov., C. graniticola sp. nov., and C.yelagiriensis sp. nov. differ from each other by 9%–18% uncorrected ND2 sequence divergence and other South Asian Cnemaspis by 17%–33% and are morphologically distinguishable from all regional congeners and each other. The new species are known from only granite boulders in montane habitats (>1,000 m asl.), just 60–120 km straight-line distance apart from each other. A fossil-calibrated timetree and ancestral area reconstructions indicate South Asian Cnemaspis originated in Western Ghats forests with initial divergence in the Paleocene-Eocene making it perhaps the oldest Indian squamate clade. Cnemaspis that occur in Peninsular India in the dry zone outside the Western Ghats form three independently derived clades that occur in significantly warmer and drier habitats than those in the Western Ghats. The discovery of a Miocene divergent clade from rocky hills on the southern edge of the Mysore Plateau reveals these habitats as novel, long-term climate refugia. This adds to the body of work revealing ancient origins of taxa in the Indian dry zone and supports the Mysore Plateau as an important and overlooked hot spot of lizard biodiversity.  相似文献   

7.
Phylogeography of the Southeast Asian stone oaks (Lithocarpus)   总被引:4,自引:1,他引:3  
Abstract Aim To describe current geographical patterns of genetic diversity and infer the historical population dynamics of the stone oaks (Lithocarpus) in Southeast Asia. Location We sampled three populations in Indochina: (1) Yunnan province, China; (2) Pyin Oo Lwin area, Myanmar and (3) north‐western Vietnam; two in western Borneo: (1) South‐western Sarawak and (2) West Kalimantan, Indonesia; two in central Borneo: (1) north coastal Sarawak and (2) north‐eastern Sarawak, Malaysia; and two in northern Borneo: (1) Central Sabah and (2) Northern Sabah, Malaysia. Methods A phylogenetic reconstruction of chloroplast DNA sequence variation from numerous individuals of multiple species was used to determine geographical distribution of genetic diversity. A resampling scheme was used to determine the significance of these patterns at different hierarchical levels of the phylogeny. Results were compared with a previously published set of nuclear DNA sequence data. Results A high level of chloroplast sequence variation was found, which was divided equally between two major clades separated by four non‐homoplasious changes. One clade was confined to the island of Borneo, while the other was widespread. Strong geographical structure was observed in the chloroplast sequence variation. The Indo‐chinese populations were much more closely related than expected, comparable with the highly endemic and isolated population on the western coast of Borneo. Conversely, individuals from the Kelabit Highlands were found to be more distantly related than expected. The highest levels of genetic endemism were observed in western Borneo. More geographical structure was observed in the Bornean clade than in the Widespread clade, because of limited genetic diversity in the Widespread clade. Relatively weak geographical structure was found in the nuclear sequence variation: only populations in southern China and central Sabah were significantly related. Conclusions The high levels of chloroplast genetic diversity and the persistence of an ancestral haplotype that is a single step away from a haplotype found in Castanopsis indicates the continuous presence of tropical rain forest in Southeast Asia throughout the evolutionary history of the genus (c. 40 Myr). This conclusion is supported by the high frequency of numerous endemic types observed in every population and the relatively few number of ‘missing’ haplotypes. This situation suggests both limited migration and limited extinction. In contrast, the nuclear genetic diversity contained less geographical structure, indicating that our taxonomic sampling among populations was unbiased and that gene flow mediated through pollen is less geographically restricted and contains less geographical structure than purely seed‐mediated (chloroplast) gene flow. The most likely scenario suggested by the evidence involves four major patterns: (1) the widespread presence of an ancestral haplotype; (2) the large degree of separation (four non‐homoplasious base pairs) between the types found in the two major clades; (3) the concentration of derived types from both major clades found in central and northern Borneo; and (4) the molecular endemism found in each location. These patterns suggest four primary things about the population dynamics of Lithocarpus since the late Eocene: (1) populations have either spanned the entire region throughout much of the evolutionary history of the genus or substantial populations have persisted in both Indochina and Borneo with limited migration between them; (2) significant fragmentation has occurred subsequently between the Asian mainland and the Melasian island archipelago, leading to independent genetic diversification in both regions; (3) several locations possessing significant independent histories, have experienced little migration and have never gone completely extinct; and (4) that the central highlands of Borneo have been re‐invaded from the north and the west. The timing of these events is difficult to ascertain but probably predate the Quaternary Period, suggesting that although the recent ice ages might have affected the overall distribution of rain forest in Southeast Asia, it managed to persist in most regions even through the most dramatic drying events.  相似文献   

8.
Phylogenetic relationships within the genus Pieris (Ericaceae) were investigated based on the rbcL and matK genes along with five spacer sequences of chloroplast DNA to address questions regarding the phylogeography of the genus in association with insular plants on the Ryukyu Islands. The most parsimonious trees indicated that P. floribunda from eastern North America is a sister taxon to the remaining taxa examined, and suggested that the East Asian taxa examined are monophyletic. A morphologically cohesive group, section Pieris, was revealed to be paraphyletic. Within the East Asian clade, insular endemics from the Ryukyu Islands, Taiwan, and mainland Japan formed a sister group to P. formosa from the Himalayas and southern China. Our data suggest that the insular endemics of the Ryukyu Islands and Taiwan arose via allopatric divergence as a result of a paleogeographical land configuration of a landbridge during the early–middle Pleistocene in the Quaternary Period.  相似文献   

9.
The genus Nepalomyia is the largest genus in the subfamily Peloropeodinae, with 47 described species. In the present paper the Nepalomyia pallipilosa species group is established for the following three described species and seven new species: Nepalomyia biseta sp. n., N. emeiensis sp. n., N. guangxiensis Zhang et Yang, N. liui sp. n., N. pallipilosa (Yang et Saigusa), N. ruiliensis Wang et Yang, N. sichuanensis sp. n., N. ventralis sp. n., N. yangi sp. n. and N. zengchengensis sp. n. Information on their distribution is also given or updated.  相似文献   

10.
We present the first extensive and integrative analysis of niche evolution based on climatic variables and a dated molecular phylogeny of a heterogeneous avian group of Southeast Asian scimitar babblers of the genus Pomatorhinus. The four main clades of scimitar babblers have species that co-occur in similar areas across southern Asia but some have diverged at different timeframes, with the most recently evolved clade harboring the highest number of species. Ecological niche models and analysis of contributing variables within a phylogenetic framework indicate instances of convergent evolution of members of different clades onto similar ecological parameter space, as well as divergent evolution of members from within clades. Pomatorhinus species from different clades occupying Himalayan foothills show convergence towards similar climatic tolerances, whereas within a clade, allopatric sister-species occurring in the Himalayas have diverged to occupy different climatic parameter spaces. Comparisons of climatic tolerances of Himalayan foothills taxa with species distributed further south in Assam/Burma and Burma/Thailand indicate convergence towards similar parameter spaces in several climatic variables. Niche overlap was observed to be lower among species of the youngest clade (ruficollis) and higher among species of older clades (ferruginosus). Analysis of accumulation of ecological disparity through time indicates rapid divergence within recent time frames. As a result, Himalayan taxa originating at different temporal scales within the four main scimitar babbler clades have differentiated ecologically only in recently diverged taxa. Our study suggests that the repeated orogenic and climatic fluctuations of the Pliocene and Pleistocene within mainland Southeast Asia served as an important ecological speciation driver within scimitar babblers, by providing opportunities for rapid geographic expansion and filling of novel environmental niches.  相似文献   

11.
Three new species of Curimatopsis are described from major tributaries of the Amazon basin. Curimatopsis guaporensis n. sp., from the Rio Madeira, belongs to the Curimatopsis evelynae clade and can be distinguished by the distinctive shape of the dark blotch on the caudal peduncle and by the position and shape of the nostrils. Curimatopsis pallida n. sp., from the Rio Negro, also related to C. evelynae, is distinguished from all congeners by the complete absence of pigmentation on the lateral surface of the caudal peduncle. Curimatopsis jaci n. sp., apparently endemic to the upper Rio Tapajós, belongs to the Curimatopsis macrolepis clade and differs from all congeners in details of body pigmentation. Meristic and morphometric features supplement diagnoses for the three new species. These species are hypothesized to belong to the two main clades of Curimatopsis on the basis of previous studies of osteology and external morphology and supplement a recent genetic study that revealed several cryptic and yet undescribed species within the genus. An updated identification key to the species of Curimatopsis is also provided.  相似文献   

12.
To more confidently assess phylogenetic relationships among astome ciliates, we obtained small subunit (SSU) rRNA sequences from nine species distributed in six genera and three families: Almophrya bivacuolata, Eudrilophrya complanata, Metaracoelophrya sp. 1, Metaracoelophrya sp. 2, Metaracoelophrya intermedia, Metaradiophrya sp., Njinella prolifera, Paraclausilocola constricta n. gen., n. sp., and Paraclausilocola elongata n. sp. The two new species in the proposed new clausilocolid genus Paraclausilocola n. gen. are astomes with no attachment apparatus, two files of contractile vacuoles, and an arc-like anterior suture that has differentiations of thigmotactic ciliature on the anterior ends of the left kineties of the upper surface. Phylogenetic analyses were undertaken using neighbor-joining, Bayesian inference, maximum likelihood, and maximum parsimony. The nine species of astomes formed a strongly supported clade, showing the subclass Astomatia to be monophyletic and a weakly supported sister clade to the scuticociliates. There were two strongly supported clades within the astomes. However, genera assigned to the same family were found in different clades, and genera assigned to the same order were found in both clades. Thus, astome taxa appear to be paraphyletic when morphology is used to assign species to genera.  相似文献   

13.
14.
Evolutionary relationships in the widely distributed velvet worm Peripatopsis balfouri sensu lato species complex were examined using DNA sequence data, gross and SEM morphology. Sequence data were generated for the COI mtDNA and the 18S rRNA loci and analysed using a Bayesian inference approach, maximum likelihood and maximum parsimony. Phylogenetic analyses of the combined DNA sequence data revealed that Peripatopsis clavigera specimens from the southern Cape (clade 1) was sister to P. balfouri sensu lato specimens from the Cederberg Mountains (clade 2). Within the main P. balfouri sensu lato species complex, three addition clades could be discerned (clades 3, 4 and 5). The obligatory troglobitic species Peripatopsis alba was equidistant between the Cape Peninsula and adjacent interior (clade 3) and the two Boland and Hottentots Holland Mountains (clades 4 and 5). On the Cape Peninsula, P. stelliporata specimens nested among the sympatric P. balfouri sensu lato specimens. The Cape Peninsula specimens were sister to specimens from Jonkershoek site 1, Kogelberg and Simonsberg. Two Boland clades were retrieved, comprising Du Toit's Kloof, Bain's Kloof and Mitchell's Pass and sister (in clade 4) to specimens from the Boland and adjacent Hottentots Holland Mountains in clade 5. These results revealed complex biogeographic patterning in the P. balfouri sensu lato species complex. The presence of sympatric, yet genetically discrete species pairs at six of the sample localities (Du Toit's Kloof, Simonsberg, Jonkershoek sites 1 and 2, Kogelberg and Landroskop) suggests that there is reproductive isolation between the lineages. Divergence time estimations suggest a Miocene/Pliocene/Pleistocene cladogenesis. A taxonomic revision of the P. balfouri sensu lato species complex was undertaken to stabilize the taxonomy. P. clavigera is monophyletic and retained for the southern Cape specimens, P. balfouri sensu stricto is now confined to the Cape Peninsula and adjacent interior, while P. stelliporata is regarded as a junior synonym of the latter taxon, P. alba is endemic to the Wynberg Cave systems on the Cape Peninsula. Three novel species (Peripatopsis cederbergiensis, sp. n., Peripatopsis bolandi sp. n. and Peripatopsis purpureus, sp. n.) are described.  相似文献   

15.
The continental coasts and remote islands in the high-latitude Southern Hemisphere, including the subantarctic region, are characterized by many endemic species, high abundance of taxa, and intermediate levels of biodiversity. The macroalgal flora of these locations has received relatively little attention. Filamentous green algae are prolific in the intertidal of southern islands, but the taxonomy, distribution, and evolutionary history of these taxa are yet to be fully explored, mostly due to the difficulty of access to some of these locations. In this study, we examined specimens of the order Cladophorales from various locations in the high-latitude Southern Hemisphere including the subantarctic (the Auckland Islands, Bounty Islands, Campbell Island, Macquarie Island, and Kerguelen Islands), as well as mainland New Zealand, the Chatham Islands, Chile, and Tasmania. The analyses of the rDNA sequences of the samples revealed the existence of two new clades in a phylogeny of the Cladophoraceae. One of these clades is described as the novel genus Vandenhoekia gen. nov., which contains three species that are branched or unbranched. The amended genus Rama is reinstated to accommodate the other clade, and contains four species, including the Northern Hemisphere “Cladophora rupestris.” In Rama both branched and unbranched morphologies are found. It is remarkable that gross morphology is not a predictor for generic affiliations in these algae. This study illustrates that much can still be learned about diversity in the Cladophorales and highlights the importance of new collections, especially in novel locations.  相似文献   

16.
Abstract.  A new Oriental fishfly genus, Sinochauliodes gen.n. , is described, including four species: S. fujianensis ( Yang & Yang, 1999 ) comb.n. , S. griseus ( Yang & Yang, 1999 ) comb.n. , S. maculosus sp.n. and S. squalidus sp.n. A cladistic analysis based on adult morphological characters clarified the phylogenetic status of the new genus and allowed the reconstruction of the intergeneric relationships of the subfamily Chauliodinae. Two main clades within Chauliodinae were recognized from the cladistic analysis. The Asian fishflies, together with the two Nearctic genera, Chauliodes and Nigronia , formed a monophyletic lineage, and the new genus was assigned as the sister group to the genus Parachauliodes . The biogeography of the Asian fishflies is discussed.  相似文献   

17.
The Empis macrorrhyncha group (Diptera: Empididae) from cool to warm temperate areas of South America and Australia is diagnosed and cladistically analysed, and five new species, Empis animosa sp.n. , E. austera sp.n. , E. maculosa sp.n. , E. occidentalis sp.n. and E. pedivillosula sp.n. , are described. Cladistic analysis of 23 adult morphological characters for 14 species of the group generated a single tree of 28 steps (CI = 0.82; RI = 0.93). Monophyly was established on the basis of a single apomorphy, possession of a bilobed cercus of the male hypopygium. Three main clades were inferred: clade 1 included three Patagonian and a single southwestern Australian species; clade 2 included two species from southeastern Australia; clade 3 included a large Patagonian group of five species and a single southeastern Australian species. The E. fulvicollis complex (clade 1) is a sister‐group of the E. macrorrhyncha complex (clades 2 + 3). A provisional historical biogeographic hypothesis is advanced correlating the appearance of the South American and Australian sister lineages with the timing of the break‐up of Gondwana.  相似文献   

18.
Capelatus prykei gen. et sp.n. , a distinctive new lineage of copelatine diving beetle, is described from the greater Cape Town area of the Western Cape Province, South Africa, on the basis of both morphological and molecular data. The genus‐level phylogeny of Copelatinae is reconstructed using a combination of nuclear and mitochondrial DNA regions, demonstrating that Capelatus gen.n. has no close relatives within the Afrotropical region, instead forming a clade with the Palaearctic Liopterus and largely Australasian Exocelina. Capelatus gen.n. apparently represents a striking example of a phylogenetically isolated Cape lineage, which also appears to be narrowly endemic and endangered by ongoing habitat loss.  相似文献   

19.
Heterotermes Froggatt is a subterranean termite genus consisting of 30 living described species worldwide, with nine occurring in the New World. Herein we provide a molecular phylogeny, using both mitochondrial and nuclear markers, of all New World species of Heterotermes, including biogeographical analysis, and describe a new species from Paraguay and Bolivia, based on morphological and molecular evidence. Our analysis recovered the New World species as paraphyletic to a monophyletic Australian clade. Within this New World + Australian clade, two monophyletic major groups were formed c. 28 Ma: the aureus- and tenuis-groups. The aureus-group has a disjunct and broad distribution consisting of two clades. The first clade extends into the Nearctic region and a second is composed of a branch in the Caatinga and Cerrado biomes (H. sulcatus Mathews) and a branch in the Chacoan biome (a new species, Heterotermes lauralinearum Carrijo sp.n. ). The tenuis-group is composed of four broadly distributed Neotropical species and the Australian clade. A single dispersion event from South America to Australia probably occurred between 13 and 24 Ma. Heterotermes crinitus Emerson was the first to diverge, being sister group of all other species in the tenuis-group, followed by Heterotermes assu Constantino. An analysis of the historical biogeography of Heterotermes suggests that jump dispersal was the most important cladogenetic process for the genus. This study is the most comprehensive phylogeny of Heterotermes and contributes to the understanding of termite evolution and geographic distribution in the New World, complementing recent studies focused on worldwide patterns. This published work has been registered on Zoobank, http://zoobank.org/urn:lsid:zoobank.org:pub:8951A29B-8B69-4CD5-B9DF-2C70D4628D97 .  相似文献   

20.
The first two fossil species of the canthyloscelid genus Synneuron are described based on compression wings. Synneuron eomontana sp. nov. is described from the Middle Eocene Coal Creek Member of the Kishenehn Formation, in the USA, and Synneuron jelli sp. nov. is described from the Lower Cretaceous Koonwarra Fossil Bed of the Korumburra Group, in Australia. The wings are illustrated and compared to the extant species of the genus, to species of the three other recent genera of Canthyloscelidae and to an anisopodid. A phylogenetic analysis of the relationships between the species of Synneuron was performed. The Eocene fossil S. eomontana appears as sister of the pair of recent Holarctic species of the genus, while the Australian Cretaceous species S. jelli is sister of the clade with the species of Synneuron of the northern hemisphere. The sister group of Synneuron is the canthyloscelid clade (Hyperoscelis + Canthyloscelis), for which a middle Jurassic fossil is known. At the early Cretaceous, Gondwana was already separated from Laurasia and the disjunction between the species of Synneuron in Australia and the northern hemisphere clade of the genus suggest a true pangeic origin for the genus. The biology of the canthyloscelid larvae is shaped by its trophic specialization—xylosaprophagous. This suggests that the transition from the Pangean Jurassic gymnosperm-dominated forests to the late Cretaceous angiosperm-dominated forests may be related to the low recent diversity of Synneuron or of the canthyloscelids in the world—and maybe to the extinction of the genus in the southern hemisphere. This major turnover of the vegetation type along the Cretaceous may be also somehow related to the complete extinction of other groups of flies strictly associated with gymnosperms, as may be the case of the lower brachyceran family Zhangsolvidae. This speculation needs additional corroboration from other groups, that will become available with the combination of systematics, paleontology and biogeographical information of different early Cretaceous clades.  相似文献   

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