Orthocentrus dorsofuscus, Humala, 2019

Humala, Andrei E., 2019, Mexican species of the genus Orthocentrus (Hymenoptera, Ichneumonidae: Orthocentrinae), Zootaxa 4709 (1), pp. 1-83 : 10-12

Orthocentrus dorsofuscus sp. nov.

( Figs 2 B , 9 B , 13 B , 16 B , 19 )

Material examined. Holotype ♀: México, Tamaulipas, Palmillas, Ej. Llano de Azúa Juniperus y mat. espinoso, 1620 m, MT, 28.VIII–10.IX.2016, leg. E. Ruíz Cancino & J.M. Coronado B. ( UAT).

Description. Female. Body length 3.0 mm, Fore wing length 2.5 mm.

Face medially 0.85 × wider than high; face smooth and polished, densely punctate medially, inner orbits diverging downwards; eyes scarcely setose, dorsal ridge of face inbetween antennal sockets without a median prominence; profile straight except dorsal third slightly impressed, edge of clypeus convex, antennal sockets on a high shelf, (Hw/Fp = 4.1); subocular sulcus fine, slightly bent towards occiput; maxillary palp reaching slightly beyond fore coxa. In dorsal view, head posteriorly deeply concave, temples distinct, about 0.25 × eye width, posterior ocelli distant from eye by 0.8 × ocellar diameter, indistinct ocellar-ocular groove present as vague impression. Minimum distance between antennal sockets about one third diameter of socket; antenna thick, curled, with 24 similar-sized transverse-quadrate flagellomeres which not gradually shortening apically; basal flagellomere 0.9 × as long as wide and about 0.3 × of the length of scape; scape parallel-sided.

Mesosoma smooth and polished; mesoscutum with indistinct shallow notauli; in profile, scutellum not high; metapleuron not particularly convex; propodeum coriaceous with posterior transverse carina present between lateral longitudinal carinae and pleural carina; posterior stubs of lateral longitudinal carinae reaching spiracles, spiracles small.

Legs all slightly flattened, broad; coxa and femur polished, tibia and tarsus coriaceous-granulate; hind coxa 1.1 × as long as first tergite, hind femur 2.7 × as long as high, hind tibia 4.1 × as long as apically wide; tibiae with spine-like setae.

Wings not particularly narrow; fore wing with areolet closed (vein 3rs-m weakly sclerotized), large, slightly transverse, 2m-cu meeting areolet at apical 0.6, vein Rs straight. Radius (Rs+2r) meeting stigma at about middle; nervulus inclivous, postfurcal; hind wing with nervellus bent, not intercepted.

First tergite elongate, slightly widening apically, 1.5 × as long as apically wide, with irregular longitudinal sculpture, well-developed dorsal carinae and transverse impressions originating at about middle of tergite, sloping posteriorly, not meeting centrally. Second tergite 0.8 × as long as apically wide with irregular longitudinal sculpture; transverse impressions originating at apical third of tergite, meeting centrally; basal thyridia oval, well-defined, contrastingly coloured. Third tergite coriaceous basally with basal thyridia narrow, transverse. Ovipositor almost straight, thin, without dorsal notch; ovipositor sheath pointed, with setae longer than sheath width, backwards pointing.

Body largely setose except eyes, pronotum, mesopleuron and metapleuron; setae very scattered on propodeum, tergites and posterior coxae.

Dark brown except fore and mid legs, upper central face, malar space, propleuron, lower and hind corner of pronotum, lower mesopleuron and narrow apical margins of tergites 2 and 3 yellowish; frontal orbits from antennal sockets up to the level of lateral ocelli yellow; fore and mid coxae and trochanters, mouthparts, tegulae, and sternites creamy; hind coxa dorsally, hind femur and tibia except for yellowish basal band mainly fuscous.

Male. Unknown.

Biology. Hosts unknown. The single specimen was collected at mid-altitude site with Juniperus .

Distribution. Mexico (Tamaulipas).

Etymology. Named after the distinctly contrasting pale ventral part and dark dorsal part of mesosoma.

Comments. Compared with the other species that have antennal sockets on a high protruding shelf, thick, curled antennae, closed areolet, and whole body not laterally flattened, the mesosoma and coxae 3 bicoloured, areolet in fore wing as wide as high and eyes with scarce setae (unlike in O. areolatus and O. pentagonum ). Similar to O. fuscipes but differs in the narrower face, more strongly sculptured first and second tergites and bicoloured mesosoma.

Figures

FIGURE 2. Lateral views: Orthocentrus shieldsi species-group (in part). A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus. Scale 1.0 mm.

FIGURE 9. Faces: Orthocentrus shieldsi and O. montanus (in part) species-groups. A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus, G: ocampo, H: vulgaris, I: zaldivari, J: khalaimi, K: malaris, L: montanus. Scale 0.2 mm.

FIGURE 13. Heads in dorsal view: Orthocentrus shieldsi and O. montanus species-groups. A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus, G: ocampo, H: vulgaris, I: zaldivari, J: khalaimi, K: malaris, L: montanus, M: montezuma, N: sierrae, O: tlaxcalensis. Scale 0.2 mm.

FIGURE 16. Basal tergites: Orthocentrus shieldsi and O. montanus species-groups. A: areolatus, B: dorsofuscus, C: fuscipes, D: kasparyani, E: lostuxtlasi, F: microphthalmus, G: ocampo, H: vulgaris, I: zaldivari, J: khalaimi, K: malaris, L: montanus, M: montezuma, N: sierrae, O: tlaxcalensis. Scale 0.2 mm.

FIGURE 19. Distribution map of Orthocentrus in Mexico. O. areolatus, O. dorsofuscus, O. hispidus, O. malaris