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The hypothesis is advanced that nervous control of behavior is imprecise and that some behavioral evolution involves a selective pruning of variants similar to that which occurs in embryological canalization. Variations documented in many previous behavioral studies may have been selectively advantageous and therefore do not provide appropriate tests for the imprecision hypothesis. The spinning behavior of individual larvae of the fly Leptomorphussp. satisfies the conditions for a sufficient test. As predicted by the hypothesis, the behavior is extremely variable at several levels of organization (attachment sites, movements between sites, sequences of up to four movements, pairs of sequences, and entire trains of spinning behavior between movements forward), even when the larva is on a relatively uniform substrate. The temporal clumping of different variations, the combination of responses to large discontinuities and lack of responses to smaller discontinuities, and the improbability of selection favoring such a wide variety of responses all suggest that some of the variation in high as well as low levels of organization of behavior does not represent adjustments to irregularities in the substrate. Larvae can reduce or repress this behavioral variability, as stereotypy increased at several levels of organization when larvae encountered large irregularities in their environments. Variation in spinning by Leptomorphussp. larvae may thus be due to imprecision in the nervous control of their behavior.  相似文献   

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Exechia and Bibio have retained several plesiomorphic groundplan features of Diptera and Bibionomorpha, including a fully exposed and sclerotized head capsule, the transverse undivided labrum, the absence of movable premandibles, and undivided mandibles without combs. The fusion of the hypostomal bridge with the head capsule and largely reduced antennae are derived features shared by both taxa. The absence of teeth at the anterior hypostomal margin is a potential autapomorphy of Bibionomorpha. A basal position of Anisopodidae is suggested by a number of plesiomorphies retained in this family. Apomorphies of Bibionomorpha excluding Anisopodidae are the reduction of tentorial elements, the partial fusion of the labrum and clypeus, one-segmented antennae, the absence of a separate submental sclerite, the loss of the labial palpus, and the reduction of the pharyngeal filter apparatus. Head structures of Bibio are largely unmodified. The subprognathous orientation is one of few autapomorphic features. In contrast, the mouthparts of Exechia are highly modified in correlation with the specialized food uptake. The rasping counterrotating movements of maxillae and mandibles with teeth oriented in opposite directions are carried out by strongly developed extensors and flexors of the paired mouthparts. The modified labium mechanically supports the “drill head” formed by the mandibles und maxillae. The necessary stability of the head capsule is provided by the hypostomal bridge which also compensates the far-reaching reduction of the tentorium.  相似文献   

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The monophyly and phylogenetic relationships within the species rich Sciophilini (Diptera: Mycetophilidae) were analysed, based on 96 adult morphological characters. The cladistic analysis included 80 Sciophilini exemplar species (representing all but 1 of the 36 genera placed previously in the Sciophilini) and 11 outgroup taxa of other mycetophilid tribes. The monophyly of Sciophilini was supported in the parsimony analysis by four synapomorphies. The tribe now contains 34 genera: Acnemia Winnertz, Acomoptera Vockeroth, Adicroneura Vockeroth, Afrocnemia Matile, Allocotocera Mik, Anaclileia Meunier, Aneura Marshall, Austrosciophila Tonnoir, Azana Walker, Baeopterogyna Vockeroth, Cluzobra Edwards, Drepanocercus Vockeroth, Duretophragma Borkent gen.n. , Eudicrana Loew, Leptomorphus Curtis, Loicia Vockeroth, Megalopelma Enderlein, Monoclona Mik, Morganiella Tonnoir & Edwards, Neoallocotocera Tonnoir, Neoaphelomera Miller, Neotrizygia Tonnoir & Edwards, Neuratelia Rondani, Paramorganiella Tonnoir, Paratinia Mik, Paratrizygia Tonnoir, Parvicellula Marshall, Phthinia Winnertz, Polylepta Winnertz, Sciophila Meigen, Stenophragma Skuse, Tasmanina Tonnoir, Taxicnemis Tonnoir & Edwards, and Trizygia Skuse. Four genera placed previously in Sciophilini (Coelophthinia Edwards, Impleta Plassmann, Speolepta Edwards and Syntemna Winnertz) are transferred to the Gnoristini. Neoneurotelia Shinji and Neoparatinia Shinji are considered nomina dubia . Diagnoses are given for all genera in the tribe. Duretophragma gen.n. is described for the following species (all of which are comb.n. ): Duretophragma andina (Duret), Duretophragma argentina (Duret), Duretophragma glabanum (Johannsen), Duretophragma fusca (Edwards), Duretophragma humeralis (Edwards), Duretophragma intermedia (Edwards), Duretophragma longifurcata (Freeman) (type species), Duretophragma morigenea (Edwards), Duretophragma naumanni (Duret), Duretophragma nigricauda (Edwards), Duretophragma obscura (Duret), Duretophragma ochracea (Freeman), Duretophragma pleuralis (Edwards) and Duretophragma similis (Johannsen). Other new generic combinations include: Trizygia albidens (Oliveira & Amorim) comb.n. , Trizygia alvesi (Oliveira & Amorim) comb.n. , Trizygia balbi (Oliveira & Amorim) comb.n. , Trizygia camargoi (Oliveira & Amorim) comb.n. and Afrocnemia stellamicans (Chandler) comb.n .  相似文献   

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The Orce region has one of the best late Pliocene and early Pleistocene continental paleobiological records of Europe. It is situated in the northeastern sector of the intramontane Guadix-Baza Basin (Granada, Andalusia, southern Spain). Here we describe a new fossil hominin tooth from the site of Barranco León, dated between 1.02 and 1.73 Ma (millions of years ago) by Electron Spin Resonance (ESR), which, in combination with paleomagnetic and biochronologic data, is estimated to be close to 1.4 Ma. While the range of dates obtained from these various methods overlaps with those published for the Sima del Elefante hominin locality (1.2 Ma), the overwhelming majority of evidence points to an older age. Thus, at the moment, the Barranco León hominin is the oldest from Western Europe.  相似文献   

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Peter H. Kerr 《ZooKeys》2014,(386):29-83
Megophthalmidia Dziedzicki is a small leiine genus (Mycetophilidae) with seven species described from the Neotropics and ten species from the Palearctic region. Two species of Megophthalmidia have been reported for North America. Recent collecting of Mycetophilidae in California and Arizona, however, shows current North American diversity of Megophthalmidia is at least on par to other regions of the world. Eight new species of Megophthalmidia are described here, increasing the number of Nearctic Megophthalmidia species to nine. Included is a particularly atypical member of the genus, M. saskia sp. n., which expands the genus concept of Megophthalmidia. Of the two species previously recorded for North America, only one actually belongs in the genus. Megophthalmidia occidentalis Johannsen, is fully described and illustrated. The other named species, M. marceda (Sherman) is illustrated and transferred to the genus Ectrepesthoneura Enderlein. A lectotype is designated for this species. A key to the species of Megophthalmidia of North America is provided. The biology of these flies is not yet known. Three of the new Megophthalmidia species – M. lenimenta, M. misericordia, and M. radiata – are only known to occur within small protected areas within the California State Park and UC Natural Reserve systems.  相似文献   

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吴鸿  徐华潮 《昆虫学报》2002,45(Z1):67-69
 报道浙江省龙王山自然保护区滑菌蚊属Leia三新种: 针尾滑菌蚊L.aculeolusa sp.nov.,长尾滑菌蚊L.ampulliforma sp.nov.和龙王山 滑菌蚊L.longwangshana sp.nov.。模式标本保存在中国农业大学昆虫标本馆。  相似文献   

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吴鸿  徐华潮 《昆虫学报》2002,45(2):67-69
报道浙江省龙王山自然保护区滑菌蚊属Leia三新种:针尾滑菌蚊L.aculeolusa sp.nov.,长尾滑菌蚊L.ampulliforma sp.nov.和龙王山滑菌蚊L. longwangshana sp.nov.。模式标本保存在中国农业大学昆虫标本馆。  相似文献   

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The phylogenetic relationships within the fungus gnat tribe Exechiini have been left unattended for many years. Recent studies have not shed much light on the intergeneric relationship within the tribe. Here the first attempt to resolve the phylogeny of the tribe Exechiini using molecular markers is presented. The nuclear 18S and the mitochondrial 16S, and cytochrome oxidase subunit I (COI) genes were successfully sequenced for 20 species representing 15 Exechiini genera and five outgroup genera. Bayesian, maximum parsimony and maximum likelihood analyses revealed basically congruent tree topologies and the monophyly of Exechiini, including the genus Cordyla , is confirmed. The molecular data corroborate previous morphological studies in several aspects. Cordyla is found in a basal clade together with Brachypeza , Pseudorymosia and Stigmatomeria . The splitting of the genera Allodiopsis s.l. and Brevicornu s.l. as well as the sistergroup relationship of Exechia and Exechiopsis is also supported. The limited phylogenetic information provided by morphological characters is mirrored in the limited resolution of the molecular markers used in this study. Short internal and long-terminal branches obtained may indicate a rapid radiation of the Exechiini genera during a short evolutionary period.  相似文献   

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Abstract A molecular phylogeny of the fungus gnat family Mycetophilidae based on the nuclear 18S, 28S, and the mitochondrial 16S rRNA genes is presented. The total alignment included 58 taxa and 1704 bp. The family was recovered as monophyletic in parsimony and Bayesian analyses. In the Bayesian analysis, Mycetophilinae and its two tribes, Mycetophilini and Exechiini, were monophyletic with good statistical support. The subfamily Mycomyinae was found consistently in a sister‐group relationship to Mycetophilinae. Gnoristinae was rendered paraphyletic, subtending Mycomyinae and Mycetophilinae. Within Gnoristinae, the genera Coelosia Winnertz, Boletina Staeger, Gnoriste Meigen group with Docosia Winnertz, usually considered to be a member of Leiinae. No support was found for the monophyly of the subfamilies Sciophilinae and Leiinae.  相似文献   

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Kerr PH 《ZooKeys》2011,(137):41-76
Six new species are described, raising the number of North American Acomoptera species to seven and the genus total to ten, and nearly doubling the number of species within the putative clade containing Acomoptera, Drepanocercus, and Paratinia. These novel species forms have implications for the concept of Acomoptera that in turn, may impact our understanding of its generic relationships and the evolution and composition of Gnoristinae and Sciophilinae. The new species, Acomoptera crispa, Acomoptera digitata, Acomoptera echinosa, Acomoptera forculata, Acomoptera nelsoni,and Acomoptera vockerothi, are compared with the type species of the genus, Acomoptera plexipus (Garrett), whose diagnostic features are imaged and illustrated for the first time. The European species, Acomoptera difficilis (Dziedzicki) is also illustrated and compared. Acomoptera spinistyla (Søli) comb. n. is transferred from Drepanocercus. A key to species is provided. Future work will seek to incorporate this knowledge into a systematic phylogenetic study of relationships between these species and their sister taxa.  相似文献   

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Background

It is conventionally accepted that the lepidopteran fossil record is significantly incomplete when compared to the fossil records of other, very diverse, extant insect orders. Such an assumption, however, has been based on cumulative diversity data rather than using alternative statistical approaches from actual specimen counts.

Results

We reviewed documented specimens of the lepidopteran fossil record, currently consisting of 4,593 known specimens that are comprised of 4,262 body fossils and 331 trace fossils. The temporal distribution of the lepidopteran fossil record shows significant bias towards the late Paleocene to middle Eocene time interval. Lepidopteran fossils also record major shifts in preservational style and number of represented localities at the Mesozoic stage and Cenozoic epoch level of temporal resolution. Only 985 of the total known fossil specimens (21.4%) were assigned to 23 of the 40 extant lepidopteran superfamilies. Absolute numbers and proportions of preservation types for identified fossils varied significantly across superfamilies. The secular increase of lepidopteran family-level diversity through geologic time significantly deviates from the general pattern of other hyperdiverse, ordinal-level lineages.

Conclusion

Our statistical analyses of the lepidopteran fossil record show extreme biases in preservation type, age, and taxonomic composition. We highlight the scarcity of identified lepidopteran fossils and provide a correspondence between the latest lepidopteran divergence-time estimates and relevant fossil occurrences at the superfamily level. These findings provide caution in interpreting the lepidopteran fossil record through the modeling of evolutionary diversification and in determination of divergence time estimates.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-015-0290-8) contains supplementary material, which is available to authorized users.  相似文献   

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We investigated the genetic diversity and phylogenetic placement of the butterflies in the genus Colotis and eight related pierid genera using sequence information from two mitochondrial and two nuclear genes. To establish the status of species, we initially barcoded 632 specimens representative of all genera and most species and subspecies in those genera. A subset was then selected for phylogenetic analysis where additional gene regions were sequenced: 16S rRNA (523 bp), EF‐1α (1126 bp) and wg (404 bp). DNA barcode results were largely congruent with the traditional classification of species in the Colotis group, but deep splits or lack of genetic divergence in some cases supported either species‐level differentiation or synonymy. Despite using information from four genes, the deeper nodes in our phylogeny were not strongly supported, and monophyly of the ‘Colotis group’ and the genera Colotis and Eronia could not be established. To preserve the monophyly of Colotis, we revive the genus Teracolus for three outlying species previously in Colotis (i.e. Colotis eris, Colotis subfasciatus and Colotis agoye), as well as the genus Afrodryas for Eronia leda. The position of Calopieris is unresolved although it appears to be well outside the molecular variation in Colotis (s.l.). A dispersal/vicariance analysis suggested that major diversification in Colotis (s.str.) occurred in Africa with subsequent dispersal to India and Madagascar.  相似文献   

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《Comptes Rendus Palevol》2008,7(7):401-405
Paleolomatia menatensis gen. and sp. n., oldest Bombyliidae sensu stricto, is described from the Paleocene of Menat (France). The new genus, based on the wing venation, is attributed to the rather ‘derived’ subfamily Lomatiinae, strongly supporting a Late Cretaceous age for the diversification of the pollinator bee flies, in relation with the floristic changes and the angiosperm radiation that occurred at the same time.  相似文献   

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Peter H. Kerr 《ZooKeys》2014,(437):109-126
California is one of the most biologically diverse regions of the world, yet the diversity of fungus gnats (Mycetophilidae) remains largely undocumented within the state. A modest survey of these flies has led to the discovery of a new genus and species of gnat that lives alongside one of the most iconic trees in the world, the giant sequoia (Sequoiadendron giganteum). Spritella sequoiaphila gen. et sp. n. is described and illustrated and its status among other mycetophilid genera is analyzed and discussed.  相似文献   

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The genus Manota is recorded from Japan for the first time. Three new species, Manota satoyamanis, Manota indahae and Manota tunoae spp. nov., are described, based on specimens collected in an ecological sampling program of arthropods in the “satoyama” landscape of Ishikawa Prefecture. “Satoyama” represents the traditional rural landscape of Japan, which is characterized by a mosaic of secondary forests, plantations, ponds and rice paddy fields. The new species raise the number of Palearctic Manota species from five to eight.  相似文献   

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