Nesolinoceras Ashmead, 1906, 2016

Santos, Bernardo F., 2016, Generic redefinition and a new species of Nesolinoceras Ashmead (Hymenoptera, Ichneumonidae, Cryptinae), American Museum Novitates 2016 (3858), pp. 1-16 : 3-5

Nesolinoceras Ashmead, 1906

Nesolinoceras Ashmead, 1906: 294–295 . Description. Type species: N. espini Ashmead, 1906 , by monotypy and original designation.

DIAGNOSIS: Nesolinoceras can be distinguished from other genera of Cryptini by the following combination of characters: apical area of clypeus with a small median tubercle (figs 3, 9); supraclypeal and supraantennal areas covered by distinct, uniformly spaced striae (figs 3,9); antenna without white band; foretibia distinctly swollen, fusiform (fig. 1); forewing hyaline with extensive fuscous bands; areolet large, pentagonal, longer than wide, distinctly convergent (figs 4, 10); T1 anteriorly without lateral tooth, its spiracle placed at midlength; ventral valve of ovipositor apically dilated and overlapping dorsal valve as a lobe (fig. 12).

DESCRIPTION: FEMALE: Forewing 7.2–10.8 mm long. Body stout, subcylindric, mostly shiny. Head. Mandible short, MLW 1.6–1.7, its apex much narrower than base, MWW 0.4–0.6; ventral tooth longer and more robust than dorsal one. Malar space moderately wide, MSM 0.6–0.7. Clypeus wide, CHW 1.9–2.1, apex about as wide as to much wider than base; CWW 1.2–2.0, basally weakly convex, apically almost concave; apical area slightly inflected, medially straight, with small median tubercle. Supraclypeal and supraantennal areas covered by distinct, uniformly spaced striae (fig. 3). Antenna with 22–23 flagellomeres; flagellum with uniform width, not enlarged toward apex, without whitish band; apex of apical flagellomere blunt, flattened, with a cluster of modified sensillae. Occipital carina sharp, uniformly curved, apically fading out shortly before reaching hypostomal carina. Gena ventrally enlarged, much wider than on dorsal portion, giving head subspherical shape in front view (fig. 9).

Thorax. Dorsal margin of pronotum regular, not swollen; epomia indistinct. Mesoscutum moderately convex, subcircular, 1.0–1.1× as long as wide, shiny, distinctly sculptured (figs 5, 8); notaulus moderately short to moderately long, reaching 0.4–0.6 of mesoscutum length, moderately impressed, slightly to distinctly convergent, its surface smooth. Epicnemial carina reaching about 0.4–0.8 of distance to subalar ridge, somewhat sinuous. Sternaulus complete, uniformly shallow throughout its length, sinuous. Postpectal carina incomplete, its median portion short, straight. Posterior margin of metanotum without teethlike projections. Transverse furrow at base of propodeum narrow and moderately deep, medially smooth. Juxtacoxal carina absent or vestigial. Pleural carina absent. Fore tibia distinctly swollen, its broadest portion at midlength, giving tibia fusiform aspect. All fourth tarsomeres distinctly bilobed, lobes subequal in length and with a cluster of apical bristles.

Propodeum. In dorsal view, 1.0–1.1× as long as wide; in profile somewhat gently rounded. Anterior margin medially slightly concave. Spiracle elliptic, SWL 1.8–2.0. Longitudinal carinae absent. Anterior transverse carina complete, sharp, medially arched. Posterior transverse carina absent.

Wings. Hyaline, forewing with extensive fuscous bands (figs 4, 10). Forewing vein 1m-cu entirely fused with 1-Rs+M, limit between two veins indistinct; 1-Rs+M with bulla placed apically, almost reaching areolet; ramellus absent; crossvein 1cu-a arising far from 1M+Rs, basad by 0.2–0.4× its own length; vein 2Cua 1.1–1.2× as long as crossvein 2cu-a; bulla at crossvein 2m-cu moderately long, occupying about half of its length, placed more anteriorly than posteriorly; areolet large, APH 1.8–2.0, longer than wide, AWH 0.7–0.9, pentagonal; crossvein 3r-m mostly to entirely spectral; crossveins 2r-m and 3r-m distinctly convergent, both veins about the same length or 3r-m slightly longer; vein 4-Rs distinctly shorter than vein 4-M. Hind wing vein M+Cu only moderately curved apically, widest point of cell 1Cu (submediellan cell of Townes) only about twice as wide as basal width; vein Cua about as long as crossvein cu-a or slightly shorter, HW1C 0.9–1.0; veins 1-Rs and 2-Rs somewhat angled, cell R1 trapezoidal; vein Cub distinct, its apical 0.5 distinctly convex; vein 2-1A reaching at least 0.9 of distance to wing margin.

Metasoma. T1 short, about 0.3× as long as T2–8 combined, stout, T1LW 1.5, apex much wider than base, T1WW 1.9–2.2, distinctly depressed; without anterior lateral tooth; ventral surface of petiole and postpetiole forming uniform straight line, postpetiole and petiole not angled; spiracle of T1 near its midlength, placed on basal 0.4–0.5; median dorsal and dorsolateral carinae absent or vestigial; ventrolateral carina faint to distinct. T2 short, T2LW 0.8–0..8, trapezoidal, T2WW 1.3–1.6; thyridium small, placed rather anteriorly on T2, distinctly wider than long; T7–8 distinctly longer than T5–6. Ovipositor moderately long, OST 1.0–1.2, stout, straight, distinctly compressed; apex of ovipositor somewhat blunt, without nodus or notch; dorsal valve without ridges; ventral valve apically dilated and overlapping dorsal valve as a lobe, with 7–8 weak to distinct teeth.

MALE: Generally similar to female. Morphological differences are usually more or less uniform within Cryptini and apply to the males of Nesolinoceras: General body size usually smaller than females. Antenna with 29–31 flagellomeres, each flagellomere usually shorter and wider than in females. Transverse furrow slightly longer than in female. Propodeum smaller, less strongly convex. First metasomal segment more slender, with T1LW around 3.2, and less widened apically, with T1WW around 1.4. T2–7 much more slender than in females.

COMMENTS: Nesolinoceras is similar to Agonocryptus Cushman , and particularly to Cryptohelcostizus Cushman. The three genera share features that are considered important in grouping gabuniine genera ( Townes, 1970; Gupta and Gupta, 1983; Aguiar, 2005), such as the pleural carina absent; T1 without a basolateral tooth; and dorsolateral carina of T1 absent or vestigial. These three genera also have the body rather stout and subcylindric, with the gena strongly inflated giving the head a subspherical shape; these features are generally common in Gabuniina but contrast with other New World members of the subtribe, such as Lagarosoma Gupta , Prosthoporus Porter , Trypha Townes , and many species of Digonocryptus Viereck , which have a more slen- der body (particularly the metasomal T1) and somewhat triangular head in front view. However, Nesolinoceras can be readily differentiated from both Agonocryptus and Cryptohelcostizus by the distinctly banded pattern in the forewing; the very characteristic shape of the areolet (large, APH>1.7, longer than wide, with veins 2r-m and 3r-m strongly convergent); and the epomia indistinct. Agonocryptus also has the apical carina of the propodeum present (vs. absent in Nesolinoceras ) and the antenna with a distinct white band (vs. absent); Cryptohelcostizus has the apical area of the clypeus without median tubercle (vs. present). The redescription of the genus presented above is largely congruent with the one provided by Townes (1970), though including a considerable number of characters not mentioned by that author. The new species N. laluzbrillante runs properly to the generic keys of Townes (1970) and Aguiar (2005).

DISTRIBUTION: Caribbean. While originally recorded exclusively from Cuba, herein the genus was also discovered in the Bahamas, Cayman Islands, and the Dominican Republic. Nesolinoceras ornatipennis has clearly dispersed between Cuba and the Bahamas, since the two landmasses were never connected ( Pindell et al., 2006). It is likely that the dispersal happened from the former to the latter; the Bahamas were exposed above the sea level only during the Pleistocene, and most of its fauna is recently derived from the Greater Antilles and exhibits little endemism ( Ricklefs and Bermingham, 2008). Such dispersal events are not surprising, since some species of Cryptinae seem to be strong fliers and have relatively large distributions (see revisions such as Townes and Townes, 1962; Aguiar and Ramos, 2011; Santos and Aguiar, 2013). It is possible that species of Nesolinoceras may be found in other Caribbean Islands. However, the genus was not discovered in Central or North America even after examination of extensive material from these areas, e.g., collections of AEIC, Instituto Nacional de Biodiversidad, Costa Rica (R. Zuñiga, personal commun.) and University of Costa Rica (P. Hanson, personal commun.).