Liberitoma compta 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 : 7-10

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

( Figs 4 , 5 )

http://zoobank.org/urn:lsid:zoobank.org:act:6E1D3226- 993D-4E53-9672-53DEB11C4A8C

Diagnosis: Antenna with thread at least one-third of first flagellomere* with five preserved segments* each with length to width ratio ~2:1. Forewing with Sc basal branch short* vertical* meeting R prior to 1-M base; Sc 2 short* slightly proclined* merging into R at level of 1-M base; Sc 1 proclined and short (about as long as Sc 2).

Etymology: The species name is derived from the Latin word ‘comptus’* meaning ornamented* adorned* referring to this sawfly being preserved in good condition.

Material: Holotype * CNU-HYM-NN2022302 . Paratypes: CNU-HYM-NN2022303 ; CNU-HYM-NN2022304 ; CNU-HYM-NN2022305 ; CNU-HYM-NN2022306 .

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-NN2022302 ( Fig. 4 ). Male. Body length 13.4 mm as preserved (excluding antennae). Surface coarsely punctated* especially on head* thorax* and the first abdominal segments ( Fig. 4A * B).

Head: Short* ovate* with eyes not small* roundish* apparently bulging* placed near the fore margin of head. Mandibles with two teeth visible.

Antenna: First flagellomere (2.1 mm) shorter than width of head (2.8 mm)* and about three times as long as thread. Thread with five segments preserved* thicker than those of type species* length (in millimetres) of each flagellomere: 0.16* 0.15* 0.15* and 0.13 (the last flagellomere was not measured owing to partial preservation)* length to width ratio ~2:1 ( Fig. 4C ).

Forewing: Sc with basal branch short* vertical; Sc 2 short* slightly proclining; Sc 1 short* oblique* basal branch meeting R well basal to 1-M base; Sc 2 merging into R basal to 1-Rs for more than 1-Rs length; Sc 1 curved* about as long as Sc 2 ( Fig. 4D ). Pterostigma fully sclerotized. Vein M+Cu slightly bent; 1-M (0.9 mm) obviously curved* about three times as long as 1-Rs (0.3 mm). Crossvein 2r-rs (0.8 mm) roughly two times as long as 1r-rs (0.3 mm)* oblique and intersecting with pterostigma near its apex; 2r-m connecting with cell 2r almost at the end of the cell* and distinctly bent towards apex of wing at middle. Cell 1r large; 2r and 2rm narrow and equal in lengths and widths.

Hind wing: Sc two-branched* forking far from apex of costal space* with hind branch very short and fore one longer* oblique ( Fig. 4E ). Basal hamuli visible in left hind wing.

Legs: Long and narrow* fore tibia 3.0 mm long* tarsus relatively shorter than that in type species* tarsus with two segments present; tarsomere I (1.42 mm) longer than tarsomere II (0.83 mm)* claw strongly bent. Middle tibia 3.4 mm long* with two apical spurs visible.

Abdomen: Male genitalia apparently not reverted* with gonocoxa and gonostylus massive* gonostylus apparently with gonomacula* volsella with stick-like digitus* cuspis and penis valves not distinct.

Remarks: Gonomacula has not been recorded in other Tenthredinoidea yet including extant Blasticotomidae .

Paratype CNU-HYM-NN2022303 ( Fig.5A, B )

Sex unknown. Generally similar to the holotype as preserved. Antenna well preserved and complete. First flagellomere (1.9 mm) obviously shorter than width of head (2.6 mm)* approximately two times as long as thread* and a total of seven thread segments preserved; length to width ratio of each flagellomere about two ( Fig. 5A ). Only left forewing partly preserved. Vein Sc three-branched* the first branch uniquely running into R very close to separation of 1-M from M+Cu; Sc 1 preserved incompletely; Sc 2 oblique* meeting R before origin of 1-Rs ( Fig. 5B ).

Paratype CNU-HYM-NN2022304 ( Fig. 5C–E )

Sex unknown. Similar to the holotype. Mandibles incompletely preserved* thick and curved ( Fig. 5D ). Legs partly well preserved* all with vaguely visible numerous fine spines. Right foreleg: tibia (2.2 mm) with two apical spurs present* almost equal in length; tarsus with four segments present* tarsomere I longer than tarsomeres II and III combined; lengths of individual tarsomeres (in millimetres): 1.01* 0.43* 0.36* and 0.34. Right middle tibia length 2.8 mm * tarsomeres I and V longer than tarsomeres II* III* and IV combined; lengths of individual tarsomeres (in millimetres): 1.24* 0.49* 0.42* 0.27* and 0.55. Right hind tibia 4.4 mm long* with no spur preserved. Left hind tibia (4.2 mm) with two apical spurs preserved* one long and one short; tarsus with five tarsomeres and one tarsal claw preserved* tarsomere I approximately equal to tarsomeres II* III* and IV combined; lengths of individual tarsomeres (in millimetres): 1.24* 0.51* 0.40* 0.35* and 0.67. Body length 9.9 mm * forewing length 12.7 mm.

Paratype CNU-HYM-NN2022305 ( Fig. 5F, G )

Female. Forewings both partly preserved. Vein Sc triple-branched* shaped like an inverted ‘Y’; the first branch intersecting with R before separation of 1-M from M+Cu; Sc 1 and Sc 2 both oblique in different directions; Sc 1 (0.28 mm) ~1.7 times as long as Sc 2 (0.16 mm)* merging into C a short distance before separation of 1-Rs from R; Sc 2 meeting R before origin of 1-Rs ( Fig. 5G ). M+Cu slightly bent; 1-M (1.1 mm) curved and about three times more than 1-Rs (0.3 mm). Crossvein 1r-rs obviously shorter than 1r-m; 2r-rs (1.3 mm) roughly three times as long as 1r-rs (0.4 mm)* oblique and intersecting with pterostigma near its apex. Cell 1r large; cell 2r and cell 2rm narrow. Body length 16.9 mm * right forewing length 13.3 mm * ovipositor length 3.0 mm.

Paratype CNU-HYM-NN2022306 ( Fig.5H–J )

Male. Body length 16.5 mm (excluding antennae). Mandible paired preserved* bent like a sickle ( Fig. 5I ). Forewings partly preserved* Vein Sc with three branches ( Fig. 5J )* the first branch merging into R before separation of 1-M from M+ Cu; Sc 1 (0.31 mm) short* ~1.9 times as long as Sc 2 (0.16 mm)* and inclining towards apex of the wing* merging into C before separation of 1- Rs from R; Sc 2 slightly oblique* meeting R before origin of 1- Rs. M + Cu slightly bent* 1-M (1.1 mm) arcuately* and approximately three times more than 1- Rs (0.3 mm). Cell 1r large; 1mcu long and lengthening to posterior margin. Male genitalia different from holotype * with gonocoxa longer* gonostylus shorter and much narrower. Body length 16.7 mm * right forewing length 10.3 mm * genitalia length 2.2 mm.

Figures

Figure 4. Liberitoma compta. Holotype* CNU-HYM-NN2022302* male.A* ventral view.B* line drawing. C* left antenna under alcohol. D* vein Sc of left forewing. E* vein Sc and hamuli of left hind wing under alcohol.Abbreviations: fla1* fla2* fla3* fla6 = first* second* third* and sixth flagellomere.Scale bars: 2 mm in A* B; 0.5 mm in C–E.

Figure 5. Liberitoma compta. A* B* dorsal view (A) and vein Sc of left forewing (B) of the paratype of CNU-HYM-NN2022303* sex unknown. C–E* ventral view (C)* mandible under alcohol (D)* and vein Sc of left forewing (E) of the paratype of CNU-HYM-NN2022304* sex unknown. F* G* dorsal view (F) and vein Sc of right forewing (G) of the paratype of CNU-HYM-NN2022305* female.H–J* ventral view (H)* mandible under alcohol (I)* and vein Sc of right forewing (J) of the paratype of CNU-HYM-NN2022306* male. Scale bars: 2 mm in A–C* F* H; 0.5 mm in B* E* G* J.