Donald W. Webb

Just How Imperiled Are Aquatic Insects? A Case Study of Stoneflies (Plecoptera) in Illinois

Abstract Nearly 5,000 historical and contemporary specimen records of stoneflies (Plecoptera) from Illinois demonstrated that this fauna is highly imperiled, boding poorly for aquatic insect communities in North America and elsewhere. Losses include two extinctions of endemics and 20 extirpations of 77 total species, a rate of loss that is higher than for either mussels or fish in Illinois. Another 19 species (24.7%) were designated as critically imperiled, being known from five or fewer locations. Two families, Perlidae and Perlodidae, experienced the greatest number of losses. Species lost were mostly those with longer life cycles and direct egg hatch. Three historically hyperdiverse regions were identified and losses in all 14 natural divisions were documented. Large river habitats and historically prairie regions have experienced the greatest proportional losses of species. This scenario probably follows for Ephemeroptera, Trichoptera, and Odonata in the Midwest and in other areas with similar glacial and cultural histories.

Monophyly and relationships of the Tabanomorpha (Diptera: Brachycera) based on 28S ribosomal gene sequences

Abstract Higher-level relationships among the earliest lineages of brachyceran Diptera remain poorly resolved by comparative morphology. Nucleotide sequence data should be useful in clarifying brachyceran relationships, especially where morphological evidence is either contradictory or controversial. We examined phylogenetic relationships among the family-level taxa of the brachyceran infraorder Tabanomorpha using sequences of a large portion of the 28S ribosomal DNA. Twenty-five species were sequenced, including five outgroup species from the Stratiomyomorpha and Xylophagomorpha. Parsimony and maximum likelihood-based phylogenetic analysis of 2,371 alignable sites yielded identical inferred tree topologies. 28S rDNA supports the monophyly of the Tabanomorpha (Vermileonidae, Rhagionidae, Pelecorhynchidae, Athericidae and Tabanidae). Our results contradict several published hypotheses that associate Vermileonidae with asiloid or eremoneuran taxa remote from the Tabanomorpha. The molecular data also support monophyly for all of the included family-level lineages, and corroborate several recent phylogenetic hypotheses based on comparative morphology.

The phylogeny of stiletto flies (Diptera: Therevidae)

The therevoid clade represents a group of four families (Apsilocephalidae, Evocoidae, Scenopinidae and Therevidae) of lower brachyceran Diptera in the superfamily Asiloidea. The largest of these families is that of the stiletto flies (Therevidae). A large‐scale (i.e. supermatrix) phylogeny of Therevidae is presented based on DNA sequence data from seven genetic loci (16S, 18S and 28S ribosomal DNA and four protein‐encoding genes: elongation factor 1‐alpha, triose phosphate isomerase, short‐wavelength rhodopsin and the CPSase region of carbamoyl‐phosphate synthase‐aspartate transcarbamoylase‐dihydroorotase). Results are presented from Bayesian phylogenetic analyses of approximately 8.7 kb of sequence data for 204 taxa representing all subfamilies and genus groups of Therevidae. Our results strongly support the sister‐group relationship between Therevidae and Scenopinidae, with Apsilocephalidae as sister to Evocoidae. Previous estimates of stiletto fly phylogeny based on morphology or DNA sequence data, or supertree analysis, have failed to find significant support for relationships among subfamilies. We report for the first time strong support for the placement of the subfamily Phycinae as sister to the remaining Therevidae, originating during the Mid Cretaceous. As in previous studies, the sister‐group relationship between the species‐rich subfamilies Agapophytinae and Therevinae is strongly supported. Agapophytinae are recovered as monophyletic, inclusive of the Taenogera group. Therevinae comprise the bulk of the species richness in the family and appear to be a relatively recent and rapid radiation originating in the southern hemisphere (Australia + Antarctica + South America) during the Late Cretaceous. Genus groups are defined for all subfamilies based on these results.

The Nearctic Species of Pandivirilia Irwin and Lyneborg (Diptera: Therevidae: Therevinae)

Abstract The genus Pandivirilia is widespread across the Nearctic and Palaearctic regions. The Nearctic species are redescribed, including the description of two new species: Pandivirilia constricta Webb and P. rufa Webb. Their phylogenetic position among the Palaearctic species and related higher therevine genera is elucidated by cladistic analysis of male and female morphological characters. A key to the Nearctic species is provided along with maps of their distribution. A neotype is designated for P. albifrons (Say) and a lectotype is designated for Psilocephala limata Coquillett. Also, Dichoglena melampodia (Loew), Ps. conspicua (Walker), and Spiriverpa nitoris (Coquillett) are placed as new combinations within Pandivirilia. P. bussi (James) is placed as a new combination within Cliorismia, making this genus Holarctic in distribution. Ps. canadensis Cole, Ps. limata Coquillett, and Ps. pollinosa Cole are placed in synonomy under P. conspicua (Walker), P. argentifrons Cole is placed in synonomy under P. melampodia (Loew), and Thereva borealis Cole is placed in synonomy under P. albifrons (Say).

BRASILIAN THEREVIDAE (DIPTERA): A CHECKLIST AND DISCRIPTIONS OF SPECIES .

Este trabalho baseia-se. no estudo de 95 especimes representando 12 especies em 5 generos. 6 especies novas, sao descritas: Hericomyia. amazonica.,sp. n. (Brasil: Amazo-nas), Brachylinga xanthoperna,sp. n. (Brasil: Roraima), Cyclotelus badicrusus, sp. n.(Brasil: Amazonas; Equador: Pinchinca). C. silacrusus, sp. n. [Brasil: Sao Paulo), Penniverpa alvadusta,sp. n. (Brasil: Amazonas) e P. alvatra,sp. n. (Brasil:Roraima). Uma lista das especies brasileiras de Therevidae e fornecida baseada na literatura e no material examinado. Sao listadas 21 especies em 7 generos, um ainda nao descrito. Sao propostas novas combinacoes e novas sinonimias.

An annotated catalogue of the New World Therevidae (Insecta: Diptera: Asiloidea)

The genera and species of New World stiletto flies (Diptera: Therevidae) are listed, with annotated references to nomenclature, synonymies and generic combinations, type localities, the primary type depositories, distribution, and citations for the most recent revisions. The genus Cyclotelus Walker, 1850 (along with its synonyms Furcifera Kröber, 1911, and Epomyia Cole, 1923a) is synonymized under Cerocatus Rondani, 1848. Ectinorhynchus fascipennis Kröber, 1911 is given the new name Cerocatus rondanii Gaimari, and Phycus rufiventris Kröber, 1911 is given the new name Cerocatus raspii Hauser. Phycus analis Kröber, 1911 and Phycus bicolor Kröber, 1911, are placed as new combinations in Cerocatus Rondani, as are the following species that were previously in combination with Cyclotelus: Furcifera achaeta Malloch, 1932, Cyclotelus badicrusus Irwin and Webb, 1992, Phycus beckeri Kröber, 1911, Epomyia bella Cole, 1923a, Furcifera braziliana Cole, 1960a, Cyclotelus colei Irwin and Lyneborg, 1981a, Thereva diversipes Kröber, 1911, Thereva fascipennis Macquart, 1846a, Psilocephala femorata Kröber, 1911, Furcifera flavipes Kröber, 1928b, Furcifera hardyi Cole, 1960a, Furcifera kroeberi Cole, 1960a, Cyclotelus laetus Walker, 1850, Furcifera longicornis Kröber, 1911, Cyclotelus nigroflammus Walker, 1850, Psilocephala nigrifrons Kröber, 1914a, Thereva pictipennis Wiedemann, 1821, Furcifera polita Kröber, 1911, Cyclotelus pruinosus Walker, 1850, Thereva ruficornis Macquart, 1841a, Psilocephala rufiventris Loew, 1869, Thereva scutellaris Walker, 1857, Cyclotelus silacrusus Irwin and Webb, 1992, Cyclotelus socius Walker, 1850 and Psilocephala sumichrasti Bellardi, 1861. Dialineura pallidiventris Malloch, 1932, Melanothereva blackmani Oldroyd, 1968, Thereva maculicornis Jaennicke, 1867 and Thereva notabilis Macquart, 1841a are placed as new combinations in Entesia Oldroyd. Henicomyia amazonica Irwin and Webb, 1992 is a new synonym of Henicomyia flava Lyneborg, 1972. Henicomyia varipes Kröber, 1912a is given revised species status from former synonymy withHenicomyia hubbardii Coquillett, 1898.

The Genus Chrysopilus in New Caledonia (Diptera: Rhagionidae)

Abstract Seventeen new species of Chrysopilus Macquart are described from New Caledonia with illustrations of the male head, wing, and genitalia. The new species are C. bicoloratus sp. nov., C. brunneabdominalis sp. nov., C. caliginosus sp. nov., C. chazeaui sp. nov., C. everti sp. nov., C. irwini sp. nov., C. frankmcalpinei sp. nov., C. mandjelia sp. nov., C. melinus sp. nov., C. noumea sp. nov., C. petersoni sp. nov., C. plautifrons sp. nov., C. sarramea sp. nov., C. shewelli sp. nov., C. teskeyi sp. nov., C. vockerothi sp. nov., and C. woodi sp. nov. Keys are provided to identify the species from New Caledonia.