Orthocentrus tergalis, Humala, 2019

Humala, Andrei E., 2019, Mexican species of the genus Orthocentrus (Hymenoptera, Ichneumonidae: Orthocentrinae), Zootaxa 4709 (1), pp. 1-83 : 32-33

Orthocentrus tergalis sp. nov.

( Figs 5 E , 10 K , 14 H , 17 H , 18 M , 25 )

Material examined. Holotype ♀: México, Veracruz, Xalapa , 1279 m, N 19°30′, W 96°55′, USBI, T1, 21. IV.2015, leg. M. López-Ortega ( UNAM).

Description. Female. Fore wing length 2.8 mm.

Face medially 1.2 × as wide as high; smooth and polished, with shallow, sparse punctures, eyes not setose, dorsal ridge of face inbetween antennal sockets without a prominence; orbits slightly divergent ventrally; face profile slightly rounded, edge of clypeus rounded, slightly impressed, antennal sockets not on a distinct high shelf (Hw/Fp = 9.9); subocular sulcus distinct, slightly bent towards occiput; maxillary palp reaching slightly beyond fore coxa. In dorsal view, head posteriorly slightly concave, temples short, slightly protruding posterior to eye, about 0.2 × eye width; hind ocellus separated from eye by 0.8 × ocellar diameter, anterior ocellus separated from eye by 2.0 × ocellar diameter, ocellar-ocular grooves present. Minimum distance between antennal sockets about 2/3 diameter of socket; antennae with apices missing, with 21+ flagellomeres, which gradually slightly shortening towards apex of antenna; basal flagellomere about 2.4 × as long as apically wide and basal flagellomere about half of the length of scape; scape with internal surface slightly convex, outer side concave.

Mesosoma polished except for inconspicuous punctation on anterior of mesoscutum and pronotum with short weak striae postero-ventrally; sometimes with vague, coriaceous microsculpture on propodeum; mesoscutum anteriorly with distinct notauli; in profile, scutellum high, metapleuron moderately convex; propodeum with posterior transverse carina complete; median longitudinal carinae complete, lateral longitudinal carinae present posteriorly, not reaching spiracle, spiracles medium-sized.

Legs broad; coxae and femora polished, femora with inconspicuous alutaceous-coriaceous sculpture, tibiae and tarsi coriaceous-granulate; hind coxa 1.1 × as long as first tergite, hind femur 3.0 × as long as high, hind tibia stout, 3.5 × as long as apically wide; tibiae with spine-like setae.

Wings not particularly narrow; fore wing without areolet, vein Rs upcurved; hind wing with nervellus intercepted at lower third.

First tergite elongate, 1.8 × as long as apically wide, in dorsal view, slightly wide at spiracles; coriaceous, with distinct median longitudinal carinae, with transverse impressions originating at about middle of tergite, sloping posteriorly, not meeting centrally. Second tergite elongate, 1.3 × as long as apically wide; coriaceous, with irregular longitudinal striae, with diagonal-transverse impressions originating at about middle of tergite, sloping posteriorly, not meeting centrally; basal thyridia absent, second thyridia developed as smooth oval areas, not contrastingly coloured. Remainder of metasoma impunctate, without thyridia. Third, fourth and fifth tergites strongly incised apically, metasoma somewhat compressed from third tergite. Ovipositor upcurved, with dorsal notch; ovipositor sheath pointed, with sparse, long, backwards-directed setae.

Body largely setose except eyes, pronotum, mesopleuron and metapleuron, setae scattered on metasoma and posterior coxae.

Brown except face, malar space, antenna ventrally yellow; frontal orbits in lower half, clypeus, mouthparts, tegula, fore and mid coxae, trochanters, trochantelli and sternites yellowish creamy; propleuron, pronotum ventrally, subalar prominence, mesosternum, mesepimeron, hind coxa dorsally and metasoma from apical 1/3 of second tergite reddish-brown. Rest of legs largely yellow to light brown, hind femur infuscate in apical half, hind tibia with basal ring yellowish creamy and fuscous dorsal surface.

Male. Unknown.

Biology. Hosts unknown.

Distribution. Mexico (Veracruz).

Etymology. Named after the unusually incised terga 3–5.

Comments. This is a distinctive species on account of the conspicuous median incisions on tergites 3–5 apically. Additionally, compared with the other species that have a complete posterior transverse carina, distinct notauli and open areolet, the temples narrow and frontal orbits in lower half yellowish creamy, unlike in O. brevicornis , O. coronadoae and O. lopezi ; subocular sulcus slightly bent towards occiput, unlike in O. brevicornis , O. latus , O. luteoclypeus and O. maculae .

Figures

FIGURE 5. Lateral views: Orthocentrus maculae species-group.A: lopezi, B: rufipleuris, C: scutellatus, D: similis, E: tergalis, F: varicolor. Scale 1.0 mm.

FIGURE 10. Faces: Orthocentrus montanus (in part) and O. maculae species-groups. A: montezuma, B: sierrae, C: tlaxcalensis, D: brevicornis, E: coronadoae, F: latus, G: lopezi, H: rufipleuris, I: scutellatus, J: similis, K: tergalis, L: varicolor. Scale 0.2 mm.

FIGURE 14. Heads in dorsal view: Orthocentrus maculae and O. ungularis species-groups. A: brevicornis, B: coronadoae, C: latus, D: lopezi, E: rufipleuris, F: scutellatus, G: similis, H: tergalis, I: varicolor, J: elongatus, K: flavoorbitalis, L: hidalgoensis, M: longiventris, N: rhombifer, O: ungularis. Scale 0.2 mm.

FIGURE 17. Basal tergites: Orthocentrus maculae and O. ungularis species-groups. A: brevicornis, B: coronadoae, C: latus, D: lopezi, E: rufipleuris, F: scutellatus, G: similis, H: tergalis, I: varicolor, J: elongatus, K: flavoorbitalis, L: hidalgoensis, M: longiventris, N: rhombifer, O: ungularis. Scale 0.2 mm.

FIGURE 18. Basal tergites: Orthocentrus wahlbergi and O. insularis species-groups. A: aztecus, B: collaris, C: contrerasi, D: mexicanus, E: minor, F: oaxacae, G: pictus, H: podagricus, I: scabrosus, J: tamaulipecus, K: veracruzus, L: ruizi. Scale 0.2 mm. Metasoma dorso-lateral view: M: Orthocentrus tergalis. Scale 0.5 mm.

FIGURE 25. Distribution map of Orthocentrus in Mexico. O. brevicornis, O. maculae, O. tergalis, O. varicolor