Distictus Townes 1966
Creators: name: Supeleto, Fernanda A.
name: Santos, Bernardo F.
name: Aguiar, Alexandre P.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Distictus

description: Genus Distictus Townes, 1966
Distictus Townes in Townes & Townes, 1966: 325. Description, keyed. Type species: Mesostenus tibialis Brullé, 1846, by monotypy and original designation.
Fenixia Aguiar, 2005a: 126–127. Description, figure, phylogenetic assessment, keyed. Type species: Fenixia curta Aguiar, 2005, by monotypy and original designation.
Distictus – Santos & Aguiar 2008: 30–39. Phylogeny, transferred to Gabuniina. — Santos 2017: 19–20. Phylogeny, transferred to “ Lymeon group” sensu Santos.
Diagnosis
Distictus can be differentiated from all other cryptine genera by the following combination of features: ventral tooth of mandible as long as dorsal tooth; apical margin of clypeus with median tooth or tubercle (Figs 6A, 7A, 8A), also laterally projected (Fig. 13C); fore tibia moderately swollen, inflated (Figs 9C, 10D, 14E); areolet medium-sized (Figs 2–3), pentagonal (Figs 1A, 7B); crossvein 3r-m distinct, distinctly convergent with 2r-m (Fig. 7B); first metasomal tergite short and stout, with anterolateral tooth (Fig. 13B), its spiracle placed at midlength (Fig. 13D); mesoscutum posteriorly flattened (Figs 4 B–4C); sternaulus distinctly sinuous (Fig. 14E); occipital carina stout, meeting hypostomal carina far from mandible base.
Redescription
Females
SIZE. Fore wing 5.12–17.08 mm long.
BODY. Subcylindric, head subspherical.
HEAD. Mandible short to moderately long, MLW 1.17–1.70, apex distinctly narrower than base, MWW 0.42–0.75; ventral tooth as long as dorsal tooth, rarely ventral tooth slightly shorter than dorsal tooth. Palpi densely pilose. Malar space moderately long, MSM 0.53–0.88. Clypeus of moderate size, CHW 0.30–0.50, basally slightly to moderately convex, more projected ventrally, sometimes distinctly emarginate at midlength, apex truncate, with median tooth; apical margin laterally projected. Antenna with 24–31 flagellomeres; flagellum gradually tapered apically; apical flagellomere blunt, with narrow apical truncation. Supra-antennal area ventrally slightly to distinctly concave, usually with distinct median line. Occipital carina strong, sharp, sometimes dorsally weakened, meeting hypostomal carina far from mandible base. Temple and gena in lateral view moderately wide.
MESOSOMA. Dorsal margin of pronotum regular, not swollen; epomia delicate or stout, usually ending far from margin of pronotum. Mesoscutum subcircular to ovoid, 0.89–1.26 × as long as wide, anteriorly moderately convex, posteriorly flattened, shiny or matte, almost always densely covered with short hairs, usually with weak to distinct longitudinal wrinkles on area enclosed by end of notauli; notaulus moderately impressed, weakly to distinctly convergent, reaching 0.43–0.84 of mesoscutum length, bearing weak to distinct striae. Epicnemial carina complete to reaching only 0.7 of distance to subalar ridge, irregular or sinuous or approximately uniformly curved. Sternaulus distinctly sinuous, complete, even if posterior 0.4 almost indistinct; usually moderately deep (except deeply impressed in D. daelus sp. nov.), bearing weak to distinct vertical wrinkles. Mesopleural suture weakly to distinctly carinulate inside. Median portion of postpectal carina absent. Posterior margin of metanotum without teeth-like projections. Propodeal furrow moderately deep, narrow, forming a polished smooth trough. Juxtacoxal carina vestigial or represented by short ridge. Pleural carina absent. Fore tibia moderately swollen. On all legs, fourth tarsomere apically bilobed, with strong apical group of bristles.
PROPODEUM. Usually longer than wide. Anterior margin medially concave or very slightly concave. Spiracle oval to elongate, SWL 1.11–2.05. Longitudinal carinae absent. Anterior transverse carina complete, distinct, slightly to distinctly arched forwards. Posterior area of propodeum with distinct, closely spaced tranverse wrinkles. Posterior transverse carina represented only by wide, low, sublateral crests.
WINGS. Fore wing usually hyaline, apex light infuscate (except fully infuscate in D. ardens sp. nov., Fig. 5C). Fore wing vein 1-Rs+M with bulla placed near basal 0.3–0.4 or centrally; ramellus absent; crossvein 1cu-a arising a little or distinctly basad of 1M+Rs; vein 2Cua 0.65–1.52 × as long as crossvein 2cu-a; crossvein 2m-cu with bulla moderately short, usually placed a little anteriorly to the middle; cell 1+2Rs pentagonal, medium sized, 0.26–0.45 × as long as vein 2m-cu, APH 0.67–1.50, AWH 0.76–1.34; crossvein 3r-m strong, spectral or nebulous; crossveins 2r-m and 3r-m distinctly convergent, both veins usually about the same length, sometimes 3r-m distinctly shorter than 2r-m; vein 3-M usually about as long as 2-M; vein 4-M tubular or nebulous. Hind wing with 6–12 hamuli; vein M+Cu usually apically moderately convex; vein M forming straight or obtuse angle with vein Cua; vein Cua almost the same length to distinctly longer than crossvein cu-a, HW1C 0.99–2.27; vein Cub straight to distinctly convex at apical half, forming straight or distinctly obtuse angle with Cua; vein 2-1A reaching at least 0.6 of distance to wing margin.
METASOMA. T1 short and stout, T1LW 1.13–1.86, apex distinctly wider than base, T1WW 1.97–3.00, with conspicuous anterolateral tooth that is rounded or angular in dorsal view, sparsely pilose; spiracle of T1 usually placed at its midlength, rarely a little before or after the middle, SPR 0.33–0.61, not or slightly prominent; dorsolateral carina represented by blunt ridge, complete or incomplete; ventrolateral carina sharp and complete, rarely incomplete; lateral depression of T1 from very shallow to distinct; median depression of T1 from absent to distinct. T2 usually short, rarely moderately long, T2LW 0.71– 1.15, usually distinctly triangular, T2WW 1.39–2.11. T2–8 pilosity almost always progressively more dense on posterior tergites, dorsally as dense as laterally or laterally denser than dorsally. Ovipositor moderately long, OST 0.49–1.00, stout, compressed, usually straight, sometimes slightly downcurved, scarcely to moderately punctate; apex of ovipositor blunt, without nodus, notch faint; dorsal valve without ridges or teeth; ventral valve apically dilated, slightly to distinctly overlapping dorsal valve, with 5–9 distinct teeth.
Males
Generally similar to the respective females. Morphological secondary sexual differences are usually more or less uniform within Cryptini, as noted by Santos & Aguiar (2013), and apply to the males of Distictus as follows. General body size usually smaller than that of females. Antenna with 27–32 flagellomeres, each flagellomere usually shorter and wider than in females, tip of apical flagellomere not modified into hammer-like structure. Propodeum smaller, less strongly convex. Fore tibia not inflated. First metasomal segment more slender than in female, with T1LW 2.62–3.71, and less widened apically, with T1WW 1.42–2.13 (compare Fig. 14D vs 14E). Tergites 2–7 much more slender than in females (compare Fig. 10D vs 10F).
Comments
Among Neotropical Cryptinae, species of Distictus are most similar to species of Agonocryptus Cushman, 1929, Cyclaulus Townes, 1970 and Mallochia Viereck, 1912. All of these genera are characterized by a somewhat elongate and subcylindric body; subspherical head with the gena slightly to strongly inflated; the apical margin of clypeus has a median tooth (sometimes indistinct in Agonocryptus). In addition, Mallochia also has the posterior transverse carina of propodeum absent or very weak. Distictus can be differentiated from Agonocryptus by having the veins 2r-m and 3r-m of the areolet distinctly convergent (Fig. 7B) (vs parallel to subparallel); HW1C> 0.99, almost always> 1.30 (vs <1.0); and ventral tooth about as long as dorsal tooth (vs distinctly longer). Distictus can also be readily separated from Cyclaulus by the presence of an anterolateral tooth on the T1 (as in Fig. 13B) (vs tooth absent).
The similarity between Distictus and Mallochia had been noticed by Kasparyan & Ruíz-Cancino (2005: 109), who went as far as to name a species of the latter genus as M. distictus (Kasparyan & Ruíz-Cancino, 2008). In fact, examination of additional comparative material showed that the species described as Distictus aurantium by Santos & Aguiar (2008) is likely to be part of Mallochia (see below). Following the generic delimitation presented in this paper, Distictus can be objectively separated from Mallochia (including D. aurantium) based on the following differences:
1. First tergite with conspicuous anterolateral tooth that is rounded or angular in dorsal view (Fig. 13B); areolet medium-sized, at least slightly longer or slightly shorter than the section of crossvein 2m-cu above the bulla (Figs 1A, 3); crossvein 3r-m strong (Figs 3, 7B), spectral or nebulous; vein 2Cua> 0.65 × as long as crossvein 2cu-a .................................................................. Distictus Townes, 1970
– First tergite without anterolateral tooth; areolet small, distinctly shorter than the section of crossvein 2m-cu above the bulla (Fig. 1B); crossvein 3r-m absent (Fig. 1B); vein 2Cua <0.60 × as long as crossvein 2cu-a ............................................................................................ Mallochia Viereck, 1912
Distribution
Neotropical (Fig. 17). Known records span the following countries: Mexico, Guatemala, Costa Rica, Colombia, Venezuela, Ecuador, Peru, Brazil, Bolivia and Argentina.
description: Published as part of Supeleto, Fernanda A., Santos, Bernardo F. & Aguiar, Alexandre P., 2019, Revision of Distictus Townes, 1966 (Hymenoptera, Ichneumonidae, Cryptinae), with descriptions of ten new species, pp. 1-64 in European Journal of Taxonomy 542 on pages 4-8, DOI: 10.5852/ejt.2019.542, http://zenodo.org/record/3378752