Cestrus Townes, 1966

Supeleto, Fernanda A., Santos, Bernardo F. & Aguiar, Alexandre P., 2020, A new species and southernmost record of Cestrus Townes (Hymenoptera Ichneumonidae, Cryptinae), Zootaxa 4822 (2), pp. 277-284 : 278

Cestrus Townes, 1966

Townes, 1966: 125, 309, 328. Original description, type species designation, synonymy, keyed.

Townes, 1970: 327, 329, 505. Keyed, description, cited as speciose taxon, figures.

Aguiar, 2005: Phylogenetic analysis (morphology), discussion, keyed.

Kasparyan & Ruíz-Cancino, 2005: 149, 159–162, 285. New species, key to Mexican species (in Spanish), figures, keyed. Santos & Aguiar, 2008: 33. Phylogenetic analysis (morphology), new characters coded.

Santos, 2017: 5, 18. Phylogenetic analysis (morphology, molecular), new characters coded, figure.

Diagnosis. Cestrus can be differentiated from all other Cryptinae genera by the following combination of features: (1) tip of ventral valve of ovipositor with a dorsal lobe that encloses dorsal valve; (2) ovipositor tip with a distinctly scabrous (microsculptured) area just basad of the teeth ( Fig. 2C ), (3) T1 rather slender, with anterolateral tooth, spiracle placed approximately at midlength; (4) mandible ventral tooth a little longer than dorsal tooth; (5) pleural carina of propodeum complete, even if weak; (6) areolet pentagonal, about as wide as high; (7) crossvein 3r-m and 2r-m distinctly convergent.

Remarks. Cestrus is a member of the Gabunia group of genera ( Santos 2017), one of the few major clades of Cryptini that is clearly morphologically diagnosable; genera of the group have the ventral tooth of mandible longer than dorsal one; fore tibia strongly inflated; spiracle of T1 placed approximately at midlength; and ventral valve of ovipositor apically partially enclosing dorsal valve. These traits have convergently evolved in other groups of Cryptini and at least some of them seem to be adaptations to attack deeply concealed hosts ( Santos & Perrard 2018). Among the genera showing this morphological syndrome, the distinctly microsculptured area in the ventral valve of the ovipositor is a distinctive feature of Cestrus , found only in the closely related genus Dineotropica Aguiar. Species of Cestrus can be differentiated from Dineotropica by having the epomia long (vs. short); T1 distinctly bent in lateral view (vs. almost straight); and crossveins 2r-m and 3r-m distinctly convergent (vs. subparallel).

Biology. Hosts are unknown.

Distribution. The genus is confined to the Neotropical Region, and at least the currently described species seem to be absent from lowland forests; all known records are from altitudes ranging from 300–2000 m.

Figures

FIGURE 2. Cestrus itatiensis sp. nov., Holotype female. A. Head, frontal view. B. Propodeum, dorsal view. C. Apex of ovipositor, left side. D. Dorsal view.