Holotype, ♀ (ZUH), “S. China: Hunan, nr Zhangjiajie, Badagong Mts, Bamaoxi, 2–3.VI.2009, 540 m, Xi-Ying Li, RMNH’09”, “CVA4252, sp. 18”.

Oblique groove of pronotum largely crenulate; setose part of ovipositor sheath 0.06 times as long as fore wing and about 0.7 times as long as first tergite (Fig. 126); clypeus truncate ventrally; hypoclypeal depression narrow slit-shaped (Fig. 131); medio-posterior depression of mesoscutum absent (Fig. 128); vein CU1b of fore wing short (Fig. 127); vein r of fore wing short (Fig. 127); vein m-cu of fore wing parallel to vein 1-M (Fig. 127); hind tibia apically and tarsus brownish.

Holotype, ♀, length of body 1.8 mm, of fore wing 2.1 mm.

Head. Antenna with 25 segments and 1.2 times as long as fore wing; third segment 1.1 times as long as fourth segment, length of third, fourth and penultimate segments 4.0, 3.5 and 2.3 times their width, respectively (Fig. 134); length of maxillary palp 0.9 times height of head; labial palp segments petiolate, rather moniliform; occipital carina rather close to hypostomal carina and dorsally absent (Fig. 132); hypostomal carina medium-sized; length of eye in dorsal view 2.1 times temple; frons flattened and glabrous, smooth; face smooth, medially weakly elevated; width of clypeus 1.6 times its maximum height and 0.55 times width of face; clypeus flattened, smooth except for some punctures and its ventral margin thin and straight (Fig. 131); hypoclypeal depression slit-like, narrow (Fig. 131); malar suture present; without punctures between malar suture and clypeus; mandible abruptly widened baso-ventrally, with medium-sized and weakly protruding ventral carina (Fig. 132).

Mesosoma. Length of mesosoma 1.2 times its height; dorsal pronope obsolescent and pronotum oblique anteriorly (Fig. 135); oblique groove of pronotum largely crenulate, remainder of sides smooth and posterior groove largely absent (Fig. 126); epicnemial area smooth dorsally; precoxal sulcus medially shallowly impressed, smooth as rest of mesopleuron; pleural sulcus smooth; mesosternal sulcus very narrow and very finely crenulate; notauli absent on disc, only anteriorly with short smooth impressions (Fig. 128); mesoscutum glabrous and strongly shiny; medio-posterior depression of mesoscutum absent; scutellar sulcus narrow and finely crenulate; scutellum smooth and slightly convex; surface of propodeum smooth, except for some short curved carinae medio-posteriorly (Fig. 129).

Wings. Fore wing (Fig. 127): pterostigma long elliptical; 1-R1 reaching wing apex and 1.3 times as long as pterostigma; r:3-SR:SR1 = 1:20:51; 2-SR:3-SR:r-m = 13:20:5; r -widened; 1-M straight and SR1 nearly so; m-cu slightly postfurcal; cu-a postfurcal and 1-CU1 hardly widened; first subdiscal cell narrowly open, CU1b short; M+CU1 nearly completely unsclerotized; vein m-cu of fore wing parallel to vein 1-M. Hind wing (Fig. 127): M+CU:1-M:1r-m = 15:16:8; cu-a straight; m-cu absent.

Legs. Length of femur, tibia and basitarsus of hind leg 4.6, 9.6 and 5.0 times as long as wide, respectively; hind femur with long and tibia with medium-sized setae. (Fig. 130)

Metasoma. Length of first tergite 1.1 times its apical width, its surface distinctly convex medially and coarsely rugose (including basally between dorsal carinae) and dorsal carinae developed in basal 0.6 of tergite, straight (Fig. 129); second suture absent; second and following tergites smooth; length of setose part of ovipositor sheath 0.06 times fore wing and 0.2 times hind tibia (Figs 126, 133).

Colour. Dark or blackish-brown; scapus ventrally and pedicellus apically yellowish; palpi pale yellowish; clypeus ventrally, mandible, tegulae and legs (but hind tibia apically and hind tarsus slightly darkened) brownish-yellow; mesopleuron partly chestnut-brown; second tergite and metasoma baso-ventrally yellowish-brown; pterostigma and veins mainly brown; wing membrane subhyaline.

Molecular data. COI, 16S, 28S (CVA 4252).

*China (Hunan).

Unknown.

Name derived from “crenulatus” (Latin for “minutely notched”) and “ferum” (suffix in Latin meaning carrying or having), because of the crenulate oblique groove of the pronotal side.

A female from Tian Ping Mt. and sampled as CVA4253 is very similar but is according to the molecular data a different species. It has the crenulate oblique groove of the pronotum, but the propodeum is steep and the segments of the labial palp are less moniliform. Molecular data from COI place it near Opiognathus and from 28S near Opiognathus + Coleopioides.

The new species runs (with some difficulty) in the key by Chen and Weng (2005) to Opius clusilis Weng & Chen, 2005. Opius crenuliferus differs by having the head roundly narrowed behind eyes in dorsal view (directly narrowed in Opius clusilis), the dorsal pronope obsolescent (distinct), length of the first tergite 1.1 times its apical width (1.4 times) and length of the third antennal segment 4 times its width (2.6 times).