Xyelocerus Rasnitsyn, 1968

Sun, Chenhui, Rasnitsyn, Alexandr P., Wedmann, Sonja, Zhuang, Jialiang, Shih, Chungkun, Ren, Dong & Gao, 2024, Revisions * new taxa * and venation transformations of the sawfly family Blasticotomidae sensu lato (Hymenoptera: ºenthredinoidea) highlight the evolution of the basal Hymenoptera, Zoological Journal of the Linnean Society 202 (1) : -

Genus Xyelocerus Rasnitsyn, 1968

Type species: Xyelocerus admirandus Rasnitsyn * 1968.

Diagnosis: Pterostigma narrow* often pale centrally. Vein Sc with stalk distant from R; Sc 1 crossvein-like (Sc 2 lost or at most dot-like small) or lost (in type species). Cell 1mcu wide* with Rs+M and 2-M aligned and parallel to 1-Cu *

Composition: Besides the type species* Xyelocerus diaphanous Gao * Ren & Shih* 2009 and Xyelocerus abruptus Sun * Rasnitsyn* Zhuang & Shih* sp. nov.

Xyelocerus abruptus Sun, Rasnitsyn, Zhuang & Shih , sp. nov.

( Fig. 1)

http://zoobank.org/ urn:lsid:zoobank.org:act:4F22E9A3-FA40-459D-A8EE-A21B31CEE004

Diagnosis: Forewing with pterostigma sclerotized. Vein Sc present* forming kink to R and touching it in a point at level of 1-M base* or preserving dot-like short Sc 2 * and with Sc 1 oblique crossvein-like. 1-M bent before 1-Rs* five times as long as 1-Rs. Rs+M* 1m-cu* and 2-Cu of subequal length.

Etymology: The species name is derived from the Latin word ‘abruptus’* meaning suddenly steep* referring to the kink of Sc before touching R.

Material: Holotype * CNU-HYM-NN2022311. Paratypes: CNU-HYM-NN2022312; CNU-HYM-NN2022313; CNU-HYM-NN2022314; CNU-HYM-NN2022315 (poorly preserved* sex unknown); CNU-HYM-NN2022316 (poorly preserved* sex unknown).

Locality and horizon: Latest Middle Jurassic (late Callovian)* Jiulongshan Formation; Daohugou Village* Wuhua ºownship* Ningcheng County* Chifeng City* Inner Mongolia * China.

Description ( Fig. 1A–C): Holotype * CNU-HYM-NN2022311. Very incompletely preserved. Sex unknown. Body length 12.8 mm * with abdomen partly preserved.

Head: ºemples convex* extending lateral beyond eyes. Antenna incompletely preserved.

Forewing: Left forewing length 11.4 mm as preserved. Pterostigma fully sclerotized. Sc forming kink and touching R in a point at level of 1-M base; Sc 1 oblique ( Fig. 1C). ºwo adventitious ‘1-Rs’ present before true one in left forewing* forming two small cells. 1-M (1.88 mm) straight and ~6.2 times as long as 1-Rs (0.30 mm). Vein M+Cu slightly bent. Crossvein 1r-rs shorter than 2-RS. Cell 1r small* 1mcu large* Rs+M* 1m-cu and 2-Cu of subequal length.

Legs: Left hind tibia narrow* 5.3 mm long.

Paratype CNU-HYM-NN2022312 ( Fig.1D, E)

Sex unknown. Very incompletely preserved* preserved similar to holotype.

Paratype CNU-HYM-NN2022313 ( Fig. 1F, G)

Female. Generally similar to holotype. Head and thorax dorsally coarsely punctated. Adventitious ‘1-Rs’ present before true one in right forewing ( Fig. 1G)* forming a small cell. Body length 19.9 mm * right forewing length 15.6 mm * ovipositor length 3.4 mm.

Paratype CNU-HYM-NN2022314 p/c

(part and counterpart) ( Fig.1H, I)

Sex unknown. Body and wings very incompletely preserved. As preserved* similar to holotype. Adventitious ‘1-Rs’ present before true one in right forewing ( Fig. 1I)* forming a small cell. Right forewing length 14.8 mm as preserved.