Eknomia Santos et Aguiar, 2012

Santos, Bernardo F. & Aguiar, Alexandre P., 2012, Phylogeny and description of Eknomia, a morphologically unusual new genus of Neotropical Cryptinae (Hymenoptera, Ichneumonidae), with three new species, Zootaxa 3237 (1), pp. 35-52 : 41-43

Eknomia Santos et Aguiar , gen. nov.

Type species. Eknomia nigra , sp. nov., by present designation.

Diagnosis. Anterior transverse carina of propodeum entirely absent; propodeum more or less uniformly strigate; clypeus nearly entirely flattened; ovipositor stout, distinctly wider subapically both at dorsal and ventral valvae; base of first tergite laterally with a weak expansion; first metasomal spiracle placed at tergite midlength or nearly so; hind margin of metanotum with tooth-like projections; propodeal furrow moderately short and narrow, smooth; areolet of moderate size, pentagonal, about as wide as high; propodeal spiracle elliptic.

Female. Fore wing 9.4–13.5 mm long. Body moderately slender to moderately stout, its surface mostly shiny. HEAD. Globose to triangular in frontal view. Mandible short, MLW 1.29–1.40, slightly tapered towards apex, MWW 1.40–1.46; dorsal tooth distinctly longer and much stouter than ventral one; ventral tooth triangular. Malar space moderately narrow, MSM 0.34–0.45. Clypeus small, distinctly wider than high, CWH 1.86–2.79; somewhat subcircular to triangular, CWW 1.62–2.41; usually nearly entirely flattened; apical margin medially straight, without median teeth, its lateral corners normal, not projected. Supraclypeal area medially very slightly prominent. Antenna with 30–36 flagellomeres; flagellum slightly enlarged towards apex; apical flagellomere cylindrical, apically rounded, with a cluster of thick, modified setae. Supra-antennal area medially with weak to distinct longitudinal carina. Occipital carina sharp, complete, meeting hypostomal carina far from mandible base; hypostomal carina strongly raised, forming distinct flange. Gena as wide at ventral margin of eye as at eye midlength.

THORAX. Dorsal margin of pronotum normal, not swollen; epomia absent or represented by short or weak ridges, when present distinct only dorsad pronotal collar. Mesoscutum moderately convex, ovoid, 1.17–1.30 × as long as wide; notaulus long, reaching 0.67–0.72 of mesoscutum length, weakly to strongly impressed, posterior apex straight; scuto-scutellar groove moderately deep, weakly to distinctly carinate inside. Subalar ridge strongly projected. Epicnemial carina reaching 0.7–0.9 of distance to subtegular ridge. Sternaulus complete, moderately impressed, weakly sinuate with weak to strong oblique striation. Mesosternum medially with short transverse wrinkles; median portion of postpectal carina indistinct to moderately long. Hind margin of metanotum with tooth-like projections. Propodeal furrow very narrow to moderately wide, medially smooth to distinctly carinate. Pleural carina absent. Fore tibia not distinctly swollen. All fourth tarsomeres distinctly bilobed, lobes of subequal length, apically with distinct cluster of stout bristles.

PROPODEUM. Moderately long, 1.30–1.39 × as long as wide, sparsely pilose, mostly to entirely strigulate. Anterior margin medially straight. Spiracle elliptic, SWL 1.78–2.00. Longitudinal carinae absent. Anterior transverse carina entirely absent. Posterior transverse carina absent or present as sublateral crests.

WINGS. Hyaline. Fore wing 1-Rs+M with bulla placed at its midlength; crossvein 1m-cu more or less uniformly curved; ramellus absent; crossvein 1cu-a arising far from 1M+Rs, basad by 0.31–0.39 × its own length; vein 2-Cu 0.55–0.82 × as long as 2cu-a; bulla at crossvein 2m-cu moderately short, occupying about 0.25 of its length, placed medially; cell 1+2Rs (areolet) medium sized, APH 0.77–1.00, pentagonal or subquadrate, AWL 0.82–1.24; crossveins 2r-m and 3r-m parallel or convergent; vein 3-M tubular. Hind wing vein M+Cu apically slightly to moderately convex; vein M forming acute angle with Cua; vein 2-Rs mostly nebulous, reaching wing margin; vein 1- Cu much longer to about as long as crossvein 1cu-a, HW1C 1.00–1.79; crossvein 1r-m with bulla at ventral 0.3; veins 1-Rs and 2-Rs distinctly angled, cell R1 trapezoidal; vein Cub distinct, forming distinctly obtuse angle with Cua; vein 2-1A reaching 0.80–0.95 of distance to wing margin.

METASOMA. T1 moderately long, about 0.34–0.48 × as long as T2–8, slender to stout, T1LW 2.38–3.35, apex moderately to much wider to distinctly wider than base, T1WW 1.70–2.36, ventrolateral outline angled; T1 base laterally with slight expansion but without distinct tooth; spiracle of T1 placed near midlength, at basal 0.52– 0.54 of tergite; median dorsal carina completely absent; dorsolateral carina absent or faint near spiracle; ventrolateral carina weak, sometimes distinct only posteriorly. Hairs at T2–8 always associated with small punctures. T2 short to moderately long, T2LW 0.73–1.60, apex moderately to much wider than base, T2WW 1.50–2.14; thyridium slightly wider than long to distinctly longer than wide. T2–8 mostly minutely and weakly coriarious; T2 sparsely pilose; T3–7 densely pilose, anteriorly with narrow glabrate area; T8 laterally densely pilose, dorsally mostly glabrate; T7–8 about as long as T5–6. Ovipositor moderately long, OST 0.68–0.72, moderately stout to very stout, straight, strongly compressed; apex of ovipositor blunt to moderately pointed, nodus distinct (in E. nigra , sp. nov. somewhat hidden by flange at dorsal valve); notch distinct as a depression just basad nodus; dorsal valve apex very slightly serrate; ventral valve with moderate to strong swelling basad nodus of dorsal valve; apex with 8–13 teeth; first three teeth very widely spaced.

Males. Generally similar to the respective females. Morphological secondary sexual differences are usually more or less uniform within Cryptini , and apply to the males of Eknomia as follows. General body size usually smaller. Antenna with significantly more flagellomeres, each flagellomere usually shorter and wider; white band of flagellum starting more apically and usually covering more articles. Propodeal furrow usually slightly longer. First metasomal segment more slender, T1LW about 4.4–6.7, and less triangular, T1WW about 1.1–1.8. T2–7 much more slender.

Comments. The new genus presents several characteristics that are unusual within Cryptini . The most evident is the absence of the anterior transverse carina, a very rare feature among the genera of the tribe. Only six Cryptini genera are characterized by an absent anterior carina ( Townes 1970): Ceratophenax Seyrig, Coccygodes Saussure , Neodontocryptus Uchida , Piambia Seyrig , Zonocryptus Ashmead , and Trypha Townes. Of these, only the last is Neotropical. Ceratophenax and Piambia are from Madagascar; Neodontocryptus is known from Taiwan only, while Coccygodes and Zonocryptus are restricted to the Ethiopian Region. Eknomia can be distinguished from all of these by the features listed under Diagnosis.

The structure of the ovipositor in the species of Eknomia seems quite notable. In all species, the ovipositor is stout, with a very small (in E. rubra , sp. nov.) to large (in E. nigra , sp. nov.) compressed flange at the dorsal valve, from its subapical portion nodus to nearly the extreme tip. This flange is minutely serrate (80 × magnification), a feature apparently not observed in any other cryptine genus. Besides, there is a subvertical line crossing the flange approximately at the position of the nodus, which seems to work as a “strengthening line.” Although not directly coded for the cladistic analyses (see above), this whole structure could represent another synapomorphy of the genus. These character states are much more evident in the type species, E. nigra , sp. nov., than in the other two species, but careful examination of E. rubra , sp. nov. and E. propodeator , sp. nov. reveals the same features.

Other distinctive features of the genus are the nearly flat clypeus, and the dorsal tooth of mandible much stouter than ventral tooth. In E. nigra , sp. nov. and E. propodeator , sp. nov., the dorsal tooth is apically very wide and somewhat quadrate.

Etymology. From the Greek eknomios, meaning “unusual, marvelous”. In reference to the very unusual general structure, as described above. Eknomia is to be treated as a feminine noun.

Biology. Unknown.

Sampling. It is noteworthy that all specimens of E. nigra , sp. nov. from Espírito Santo, as well as the holotype of E. rubra , sp. nov., were collected with Moericke traps, even though these were used concurrently with many Malaise traps, in all of the respective collecting trips. Additionally, the State of Espírito Santo has been extensively sampled with Malaise traps in over 30 localities by the UFES team. This effort did not yield a single additional specimen of Eknomia . The two remaining specimens of E. nigra , sp. nov. are from Nova Teutônia, a relatively small area, exhaustively sampled for decades, largely with Malaise traps, by Fritz Plaumann. In the course of this work and several other projects, over 10,000 specimens from Nova Teutônia were examined by the authors, and those were the only two specimens found. The other three specimens examined (the paratype of E. rubra , sp. nov. and the two specimens of E. propodeator , sp. nov.) were apparently collected with Malaise traps (label information about collecting method is available only for one specimen, but the other two are from Porter and Townes collections; both authors used mostly Malaise traps), but in these cases Moericke traps were not used, so their comparative efficiency in capturing Eknomia spp. could not be assessed.

Overall, these results are in agreement with the findings of Aguiar and Santos (2010) that, at least for Neotropical Cryptini , sampling with Moericke and Malaise traps yields very different genus-level and species-level assemblages, with about half of the genera being captured mostly or almost exclusively by Moericke traps. This seems to be the case for Eknomia . Further sampling with Moericke traps seems therefore likely to reveal more species of Eknomia in South America.

Distribution. Southern Colombia to southern Brazil ( Fig. 13 ).

Figures

FIGURE 13. Map with distribution records for Eknomia nigra, sp. nov. (circle), E. rubra, sp. nov. (square) and E. propodeator, sp. nov. (triangle).