Liberitoma incompleta Sun, Rasnitsyn, Zhuang & Shih, 2024

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), pp. 1-19 : 10-12

Liberitoma incompleta Sun, Rasnitsyn, Zhuang & Shih sp. nov.

( Figs 6 , 7 )

http://zoobank.org/urn:lsid:zoobank.org:act:ACA2BD6F-3B75-4160-9321-ADE470B52CCE

Diagnosis: Forewing with basal branch of Sc vertical* meeting R distinctly before level of 1-M base; Sc 2 obviously proclined and short* meeting R distinctly behind level of 1-M base; and Sc 1 curved and long.

Etymology: The species name is derived from the Latin word ‘incompletus’* meaning incomplete and referring to fragmentary preservation of this fossil sawfly.

Material: Holotype * CNU-HYM-NN2022307 . Paratypes: CNU-HYM-NN2022308 ; CNU-HYM-NN2022309 .

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

Description: Holotype * CNU-HYM-NN2022307 ( Fig. 6 ). Female. Body length 14.3 mm as preserved (excluding antennae). Head* thorax* and the first abdominal segment coarsely punctated.

Head: Eye big* flat* occupying most of head side* distant from fore margin of head. Antenna not preserved.

Forewing: Only left forewing partly preserved. Vein Sc with basal branch vertical* short; Sc 2 proclined* short; Sc 1 curved* long; basal branch of Sc meeting R slightly before level of 1-M base; Sc 2 merging into R at midway between basal branch of Sc and 1-Rs; Sc 1 almost reaching level of 1-Rs ( Fig. 6C ). Pterostigma fully sclerotized. M+Cu slightly bent* 1-M (1.1 mm) bent* about five times as long as 1-Rs (0.2 mm) ( Fig. 6C ). 1-Cu bent* with short adventitious veinlet within cell 1cu ( Fig. 6D ). Cell 1mcu distinctly widened apically* oblique and long. Crossvein 1r-rs obviously shorter than 2-RS; 2r-rs (0.9 mm) about two times as long as 1r-rs (0.4 mm)* oblique and meeting with pterostigma near its apex; 2r-m connecting with 2r roughly at three-quarters of its length. Cells 1r large* 2r and 2rm narrow and nearly equal in width* 1mcu long* and 2mcu wide.

Hind wing: Sc with two branches* forking far from apex of costal space* with hind branch very short and fore one longer* oblique.

Legs: Poorly preserved* except for hind femora and tibiae 4.1 mm and 3.7 mm long* respectively.

Abdomen: Ovipositor short ( Fig. 6E )* 2.3 mm long; saw sheaths wide* subtriangular* slightly longer than wide.

Paratype, CNU-HYM-NN2022308 ( Fig.7A, B )

Female: Body length 12.6 mm as preserved ( Fig. 7A ). Vein Sc three-branched in forewing* the first branch of Sc running into R much prior to separation of 1-M from M+Cu; Sc 1 (0.43 mm) relatively extended compared with Sc 2 (0.17 mm)* ~2.5 times as long as Sc 2 * and inclining to apex of the wing* merging into C a short distance before separation of 1-Rs from R* shorter than holotype; Sc 2 vertical* sub-parallel to the first branch* meeting R before origin of 1-Rs ( Fig. 7B ). M+Cu slightly bent; 1-M (1.0 mm) with curvature about three times more than 1-Rs (0.3 mm). Crossvein 1r-rs obviously shorter than 1r-m; 2r-rs (1.0 mm) about two times more than 1r-rs (0.4 mm)* oblique and meeting with pterostigma nearly its apex; 2r-m connecting with cell 2r at three-quarters of its length* and slightly bent towards apex of wing at middle. Cell 1r large* 2r narrow. Body length 12.6 mm * forewing length 11.0 mm* ovipositor length 1.7 mm.

Paratype, CNU-HYM-NN2022309 ( Fig.7C, D )

Sex unknown: Body length 10.4 mm * with head not preserved and abdomen partly preserved ( Fig. 7C ). Forewings partly preserved. Vein Sc with three branches* the first branch intersecting with R a short distance before separation of 1-M from M+Cu; Sc 1 (0.33 mm) relatively extended compared with Sc 2 (0.12 mm)* ~2.7 times as long as Sc 2 and bent to apex of the wing* merging into C before separation of 1-Rs from R; Sc 2 marginally oblique and meeting R before origin of 1-Rs ( Fig. 7D ). M+Cu slightly bent; 1-M (1.1 mm) curved* and about four times as long as 1-Rs (0.26 mm). Crossvein 2r-rs (0.9 mm) about two times as long as 1r-rs (0.4 mm)* oblique and intersecting with pterostigma near its apex; 2r-m adjoining with cell 2r at three-quarters of its length* and bent towards apex of wing at middle. Cell 1r large* 2r and 2rm narrow and equal in width. Body length 10.4 mm * right forewing length 10.5 mm.

Figures

Figure 6. Liberitoma incompleta. Holotype* CNU-HYM-NN2022307* female. A* ventral view. B* line drawing. C* vein Sc of left forewing. D* a free vein of left forewing. E* ovipositor under alcohol.Abbreviation:v 2* second valvula.Scale bars: 2 mm in A* B; 0.5 mm in C–E.

Figure 7. Liberitoma incompleta. A* B* dorsal view (A) and vein Sc of right forewing (B) of the paratype of CNU-HYM-NN2022308* sex unknown. C* D* dorsal view (C) and vein Sc of left forewing (D) of the paratype of CNU-HYM-NN2022309* sex unknown.Scale bars: 2 mm in A* C; 0.5 mm in B* D.