Distictus Townes

Santos, Bernardo F. & Aguiar, Alexandre P., 2008, Phylogeny and reclassification of Distictus Townes (Hymenoptera, Ichneumonidae, Cryptinae), with description of a new species, Zootaxa 1934, pp. 30-39 : 33-34

Distictus Townes

Distictus Townes, 1966:325 . Description, figure. Type species: Mesostenus tibialis Brullé 1846 Fenixia Aguiar, 2005:126 –127, n. syn.

Redefinition. Head. Supra-antennal area with short median carina developed near anterior ocellus, sometimes reaching almost full length of supra-clypeal area; mandible 1.0–1.5 as long as basal width; both gena and temple swollen, giving head spherical shape. Mesosoma. Epomia short and weak, sometimes indistinct from rugulosities of collar; mesoscutum ovoid, distinctly longer than wide; notauli moderately to strongly impressed, parallel or subparallel; sternaulus sinuous, strongly to weakly impressed, reaching mid coxa. Propodeum. Area in front of anterior transverse carina varying from alutaceus punctures to very strong rugulosities; spiracle weakly oval; anterior transverse carina complete, low, centrally weakly to moderately curved forward, placed approximately on mid-length of propodeum. Wings. Fore wing cell 1+2Rs 0.8–1.3 as long as width of pterostigma, same height or a little higher than its own width; crossveins 2r-m and 3r-m weakly to distinctly convergent. Hind wing vein 1-Cu 1.2–1.5 length of crossvein cu-a. Metasoma. First tegite basally with or without lateral tooth; dorsolateral carina suggested only as blunt ridge in basal or apical portions.

Comments. In the couplet of the key to Neotropical Gabuniina that leads to Nesolinoceras Ashmead, Aguiar (2005) mentions “fore wings hyaline or infuscate but never with dark bands”. Although D. aurantium has a weak dark band on the apex of the fore wing, it could hardly be mistaken with the pattern of three dark bands exhibited by Nesolinoceras ; in the following couplet, however, the distinction between D. aurantium (= Fenixia ) and some species of Agonocryptus Cushman can be misleading, because of the features “fore wing crossveins 2r-m and 3r-m distinctly convergent towards anterior margin of wing” and “hind wing vein 1-Cu about twice as long as crossvein cu-a”; in this case, the correct determination of Distictus must consider the generic redefinition provided above.

Relationships. The relationships recovered here are basically similar to that proposed by Aguiar (2005), in which Distictus ( Fenixia curta ) appears most related to Lagarosoma assitum Gupta. Current results also show that Prosthoporus always formed a clade with both species of Lagarosoma , while Trypha atriceps frequently appears as the sister group, or close to Lagarosoma + Prosthoporus . All of these are Neotropical groups predominantly known from the Brazilian Atlantic Forest; only Prosthoporus is recorded from other parts of South America. These groups also appear to be rare or uncommon. The relationships of Prosthoporus were not discussed by Aguiar (op. cit.), but it is relevant to mention that for the present work five specimens of P. t e r a n i could be studied, allowing the codification of 20 characters which could not be examined by that author, as well as all the additional 14 characters used here to expand the original matrix. The relationships of Prostophorus and Lagarosoma will be further discussed elsewhere.