Search

Summary A new species of fossil mermithid, Heydenius simulphilus sp. n. (Nematoda: Mermithidae), is described from two parasitic juvenile specimens adjacent to a male black fly (Diptera: Simuliidae) in Baltic amber. It is proposed that the nematodes emerged from their developmental sites in the haemocoel of the black fly host through a wound in the abdomen of the latter, as indicated by the release of a droplet of haemolymph and damaged cuticle. Various internal structures of the nematodes are identified and related to those found on extant developing mermithids. This is the first fossil record of mermithid parasitism of a black fly.

The Canadian Diptera fauna is updated. Numbers of species currently known from Canada, total Barcode Index Numbers (BINs), and estimated numbers of undescribed or unrecorded species are provided for each family. An overview of recent changes in the systematics and Canadian faunistics of major groups is provided as well as some general information on biology and life history. A total of 116 families and 9620 described species of Canadian Diptera are reported, representing more than a 36% increase in species numbers since the last comparable assessment by JF McAlpine et al. (1979). Almost 30,000 BINs have so far been obtained from flies in Canada. Estimates of additional number of species remaining to be documented in the country range from 5200 to 20,400.

A segregate of the so-called Australian ‘Paracnephia’ (Diptera: Simuliidae) is assigned to a new genus, Austrocnephia. The taxon is fully diagnosed and a key to constituent species presented. Two species-groups are recognized: the aurantiaca species-group, comprised of A. aurantiaca (Tonnoir 1925) and A. strenua (Mackerras & Mackerras 1950), and the tonnoiri species-group, comprised of A. fuscoflava (Mackerras & Mackerras 1948), A. orientalis (Mackerras & Mackerras 1950) and A. tonnoiri (Drummond 1931). Both species-groups are diagnosed and the included species fully redescribed. Detailed locality data is given, as is information about biology, when known. Brief comments are offered about the historical biogeography of Austrocnephia. A key to Australian simuliid genera is also provided.

Protaustrosimulium n. gen. is described for four species: two previously named species from southeastern Australia—Paracnephia pilfreyi (Davies & Györkös 1988) and Paracnephia terebrans (Tonnoir 1925)—plus two newly described ones from the southwestern-most corner of Western Australia—Prot. amphorum n. sp. and Prot. opscurum n. sp. Molecular and morphological data suggest a close relationship between members of the new genus and Austrosimulium Tonnoir 1925. Monophyly of Protaustrosimulium is supported mainly by characters of adult females, as two of the four species are known only in that life stage. Two species groups are recognized: the pilfreyi-group for Prot. pilfreyi and Prot. amphorum, and the terebrans-group for Prot. terebrans and Prot. opscurum. The constituent species in each group are distributed vicariously in southeastern and southwestern Australia—a common biogeographical pattern in Australian simuliids.

Two species of Australian Simuliidae known only from adult females and currently assigned to "Paracnephia" are re-described, as are their now-known males and immature stages. Morphological character states of "Paracnephia" fergusoni (Tonnoir) and "P." fergusoni var. (Mackerras & Mackerras) reveal that they are markedly distinct from all other Australian species, and are here assigned to the new genus—Nothogreniera—the most plesiomorphic Gondwanan Australian simuliid. Structural variation among populations of N. fergusoni suggests that this entity comprises a species complex.

Moulton, John K., Currie, Douglas C., Craig, Douglas A. (2018): A New Genus, Ectemnoides, for Seven Species of Australian Gondwanan Simuliidae (Diptera) With Description of a Novel Form of Larval Attachment. Insect Systematics and Diversity 2 (4), No. 4: 1-54, DOI: 10.1093/isd/ixy009, URL: http://dx.doi.org/10.1093/isd/ixy009

We investigated species limits and phylogenetic relationships among chromosomally distinct North American members of the Simulium malyschevi species-group. Maximum parsimony and Bayesian analyses were conducted based on 12S, COII, cyt b and ITS-1 gene sequences. In terms of species limits, monophyly was highly supported for each chromosomally and morphologically distinct taxon analysed (S. decimatum, S. defoliarti, S. malyschevi, and S. murmanum). In contrast, support for monophyly of morphologically homogeneous S. arcticum complex members was significant only in one case (S. saxosum) and not the other (S. negativum). Considering the overall topology, three principal conclusions were drawn: (i) the status of S. subvariegatum as a member of the S. malyschevi species-group remains uncertain. This species either was excluded from the malyschevi-group or formed a sister group with S. malyschevi at the base of the tree; (ii) although S. murmanum and S. decimatum branch after S. malyschevi, the position of the two species relative to each other remains unresolved; and (iii) the structurally homogeneous S. arcticum species complex was not monophyletic due to the inclusion of S. defoliarti. Further investigation may warrant changes to current malyschevi-group classification. Molecular datasets alone may be insufficient for resolving relationships among particular lineages of black flies.

Rapid and recent lineage radiations pose challenges to systematists. Using members of the highly diverseSimulium arcticumMalloch complex, we tested whether the cytochromecoxidase subunit I (COI) barcoding gene can differentiate black fly sibling species. Members of theS. arcticumcomplex were monophyletic in relation to two morphospecies and two cryptic species of theSimulium malyscheviDorogostaiskyet al.andSimulium noelleriFriederichs species-groups, respectively. Of fiveS. arcticumsibling species analysed, onlySimulium negativumAdleret al.was monophyletic. No other members of the complex could be distinguished using COI barcodes. The inability to resolveS. arcticumsibling species resulted because (1) haplotypes were shared between species and (2) the distribution of interspecific genetic distances completely overlapped the range of variation within species. Potential sources of incongruence between barcode data and species boundaries include imperfect taxonomy, inadequate genetic information, incomplete lineage sorting, and/or introgressive hybridization. We ruled out imperfect taxonomy because chromosomal, ecological, and distributional evidence support the validity ofS. arcticumsibling species. Therefore, current nomenclature should be maintained pending further study. We conclude that one or more of the latter three sources of incongruence could be responsible for the lack of reciprocal monophyly among species of theS. arcticumcomplex.

Leptocerid caddisflies have a wide variety of case forms, and therefore it might seem difficult to establish behavioral homologies at the family or generic levels. We videotaped case building in representatives of 9 genera in 8 leptocerid tribes and compared their behavior to 32 other caddisfly genera in 11 families to determine if family-specific behaviors could be identified. We also constructed a behavioral phylogeny of the 8 leptocerine genera and compared this phylogeny to an existing morphological phylogeny. Four unreversed and 1 reversed behavioral synapomorphies supported the monophyly of the Leptoceridae even though case shape varies among the genera. An analysis of 9 intergeneric behavioral characters produced 1 most parsimonious tree (length 11; consistency index: 1.00; retention index: 1.00) that differed from the morphological phylogeny in the placement of 2 genera. Six character states were homologous relative to the morphological data, 5 of which supported 2 nodes that were previous...

DNA barcoding has gained increased recognition as a molecular tool for species identification in various groups of organisms. In this preliminary study, we tested the efficacy of a 615-bp fragment of the cytochrome c oxidase I (COI) as a DNA barcode in the medically important family Simuliidae, or black flies. A total of 65 (25%) morphologically distinct species and sibling species in species complexes of the 255 recognized Nearctic black fly species were used to create a preliminary barcode profile for the family. Genetic divergence among congeners averaged 14.93% (range 2.83–15.33%), whereas intraspecific genetic divergence between morphologically distinct species averaged 0.72% (range 0–3.84%). DNA barcodes correctly identified nearly 100% of the morphologically distinct species (87% of the total sampled taxa), whereas in species complexes (13% of the sampled taxa) maximum values of divergence were comparatively higher (max. 4.58–6.5%), indicating cryptic diversity. The existence of sibling species in Prosimulium travisi and P. neomacropyga was also demonstrated, thus confirming previous cytological evidence about the existence of such cryptic diversity in these two taxa. We conclude that DNA barcoding is an effective method for species identification and discovery of cryptic diversity in black flies.

Mitochondrial based phylogenetic reconstructions often show deviations from species-level monophyly. We used the Simulium arcticum species complex (Diptera: Simuliidae) as a model system for interpreting non-monophyly in light of chromosomal data supporting species status of siblings. For cytogenetic identification of morphologically indistinguishable black fly sibling species, larvae must be preserved in Carnoy's solution, a fixative known to degrade DNA. Consequently, we reconstructed phylogenetic relationships based on 12S, COII, cyt b, and ITS-1 gene sequences obtained from larvae sampled from presumed taxon-pure localities. As species composition at 'taxon-pure' sites may have changed at the time of sampling, we performed a second study that aimed to: (1) assess phylogenetic relationships among cytologically verified members of the S. arcticum species complex using COI and COII gene sequences; (2) determine whether useable genetic information could be gleaned from Carnoy's fixed specimens; and (3) determine the extent to which Carnoy's fixative degrades DNA over time. We consistently obtained genetic data from material stored in Carnoy's solution for two to three months. Genetic analysis of samples fixed in Carnoy's solution for up to six years indicates that larvae preserved for a maximum of five years can provide useable information for molecular analysis. Our preliminary and cytologically confirmed phylogenetic analyses demonstrate that mitochondrial DNA fails to resolve species-level monophyly of chromosomally distinct S. arcticum taxa. As results of analyses based on cytologically verified larvae mirror those of our preliminary study, we rule out imperfect taxonomy as the reason for species-level non-monophyly. Although we cannot confidently reject either inadequate phylogenetic information or incomplete lineage sorting as the cause of non-monophyly, the sharing of alleles between sympatric siblings suggests introgressive hybridization between taxa. We conclude that the patterns present in the S. arcticum phylogeny likely represent the initial stages of chromosome based sibling speciation.

Sixteen species, of which 13 are new, in the subgenus Hebridosimulium Grenier & Rageau are now known. Fiji has only Simulium laciniatum, which is widely distributed on five islands. Tahiti has only one species, the enigmatic S. anatolicum. The remaining species are in Vanuatu and known from nine islands, ranging the full length and breadth of the archipelago. Hebridosimulium species are divided among two species groups. The callipygium species group is characterized, in part, by a smooth posterior abdomen in the larvae, and all but one species possess dorsal tubercles on the larval abdomen. Simulium callipygium is the type species, with the tuberculate species in a subgroup comprised of S. banksi, S. johnfrumi, S. pankumuense, and S. tuberculum. The second species group has larvae with the posteroventral abdomen markedly expanded, and all species lack dorsal tubercles. Constituents of the steatopygium species group are S. anatolicum, S. jolyi, S. laciniatum, S. lucyae, S. paradisium, S. steatopygium, S. subparadisium, S. supercilium, and S. undulatum. Two other species of this group, S. adsonense and S. spiroi, of which larvae have markedly pigmented heads, are assigned to the adsonense species subgroup. A chromosome map for Hebridosimulium is established for the first time.

The taxonomy of the genus Crozetia Davies (Diptera: Simuliidae) is reviewed. Apart from the eggs, all stages of Crozetia crozetensis (Womersley) and Cr. seguyi Beaucournu-Saguez and Vernon, are fully redescribed with only claws and genitalia detailed for the female of Cr. crozetensis. A phylogenetic analysis of the Simuliidae indicates that Crozetia is the sister group of all other members of the extant Simuliini, in agreement with current molecular evidence. Palaeogeological evidence on the age of the Crozet Islands is equivocal, but a very late Cretaceous to early Eocene age (79-54 Mya) is most likely, hence the presence of simuliids on this archipelago is not the result of vicariance from Gondwanaland. Method of dispersal to the Crozet Archipelago may have been via wind or possibly vectored by birds from Africa, as suggested by presence of a basal tooth on the adult female claw. Morphometric analysis of larvae of Cr. seguyi indicates seven instars which is typical for the Simuliidae.

A new species of black fly, Stegopterna diplomutata n. sp. (Diptera: Simuliidae) is described and illustrated. This species is most closely related to Stegopterna mutata (Malloch, 1914), with which it has long been confused. The two species are most easily distinguished based on the presence or absence of males; St. diplomutata is a diploid bisexual species that possesses males, whereas St. mutata is a triploid parthenogenetic species that lacks males. The two species are otherwise not distinguishable except through examination of their larval polytene chromosomes. Observations are provided about the evolution of triploidy in Stegopterna.