Jibaissodes peichenae Wang, Shih & Gao

Wang, Yimo, Wang, Mei, Shih, Chungkun, Rasnitsyn, Alexandr P., Yao, Jun, Ren, Dong & Gao, Taiping, 2019, A new sawfly of Megalodontesidae (Insecta, Hymenoptera, Pamphilioidea) with pectinate antennae from the Early Cretaceous of China, ZooKeys 893, pp. 115-123 : 115

Jibaissodes peichenae Wang, Shih & Gao sp. nov. Figs 1 , 2 , 3

Type material.

Holotype, specimen no. CNU-HYM-LB2018033p/c, part and counterpart.

Diagnosis.

Antenna pectinate, with 42 flagellomeres, flagellum longer than head width, proximal 28 flagellomeres with apical rami, rami gradually shortening in length toward apex of flagellum; scape almost 3 times as long as first flagellomere. Anterior margin of pronotum round, with weakly concave posterodorsal margin. Forewing with pterostigma infuscated apically; vein 1cu-a strongly curved. Hind wing vein 1-Rs nearly equal to 1r-m, slightly shorter than 1-M.

Description.

Body ( Figs 1A, B , 3A ). Fossil incomplete: distal abdominal segments missing, part of the legs invisible. Middle and surrounding regions of compound eyes and part of posterior head pale, remainder of head dark. Thorax and legs entirely or predominantly dark. First tergum except hind margin and fifth tergum laterally dark. Body about 14.9 mm (but distal abdominal segments missing), antenna 11.4 mm long; forewing about 13.6 mm in length, maximum width 6.0 mm; hind wing about 8.5 mm in length, maximum width 3.8 mm.

Head. Large, about as wide as thorax. Head ( Fig. 2A ) 5.3 mm wide and 4.6 mm long, almost circular. Compound eyes 1.8 mm long, 1.1 mm wide; right mandible large, bent and sickle-shaped; antenna ( Fig. 2D, E ) with 42 flagellomeres, basal 28 flagellomeres with rami extending from apicolateral angle, apical 14 flagellomeres without distinct rami, longest ramus about 0.8 mm in length, longest ramus slightly longer than total length of following three flagellomeres; rami gradually shortening in length toward apex of flagellum, first flagellomere much shorter than scape, 0.3 mm wide, 0.5 mm long; scape 1.4 mm long, maximum 0.4 mm in width; pedicel 0.8 mm long, maximum 0.5 mm wide.

Thorax. Maximum width 4.9 mm; pronotum short, apex round, with weakly concave posterodorsal margin. Mesoscutum large, with medial line and notauli strongly impressed, tapering to acutely rounded base; mesoscutum without line to mesoscutellum; mesoscutellum tapering to acutely sharp apex; metascutum with cenchri present and small. Metatibia ( Fig. 3B, C ) with two preapical (near distal 0.7 of length) and two apical spurs; metabasitarsus long but shorter than remaining tarsomeres combined; metafemur, metatibia, and metabasitarsus lengths 3.4 mm, 4.6 mm, and 1.1 mm, respectively.

Abdomen. Five visible segments preserved; maximum width about 5.3 mm; first tergum medially undivided, posteriorly widely excised, laterally roundly protruding, medio-anteriorly dark; fifth tergum laterally dark.

Forewing. ( Fig. 1B, C ) Wing membrane mostly hyaline with weakly infuscated bands covering base and middle regions of forewing, surrounding veins R, M+Cu, 1r-rs, 2-M, m-cu, and 2-Cu; R slightly thickened before pterostigma; pterostigma infuscated apically; 1-Rs (0.5 mm long) short and reclival; 1-M (1.0 mm long) long and slightly curved, about twice as long as 1-Rs; Rs+M straight; 1r-rs length 0.7 mm, slightly shorter than 2r-rs, 0.8 mm long; 2r-rs slightly proclival, positioned near 3/4 pterostigma; 1cu-a distinctly bent towards wing base, 1.4 mm in length; M+Cu nearly straight; 1m-cu 0.8 mm long, 0.7 times as long as 1-Cu (1.1 mm long); 1-Cu nearly equal to 2-Cu (1 mm long) in length; 2r-m slightly curved and reclival; 3r-m straight towards wing tip; 2A with shallow arch midway before 1a-2a cross-vein. Costal cell widened at point of origin of 1-Rs; cell 1r nearly equal in size to cell 2r; cell 2rm longer than cell 3rm, cell 3rm trapezoid; cell 1mcu small, nearly rectangular; cell 2mcu large, pentagonal.

Hind wing. ( Fig. 1B, D ) 1-Rs (0.5 mm long) nearly equal to 1r-m (0.5 mm long), shorter than 1-M (0.7 mm long), 1r-m straight; 1r-m and 1-M forming a nearly straight line; 3r-m present, 0.9 mm in length, strongly bent towards wing tip; 1m-cu (1.0 mm long) and cu-a (1.1 mm long) present, longer than 3r-m, cu-a distinctly bent; M+Cu nearly straight; vein 1A strongly arched.

Gender. Unknown.

Remarks.

The species can be assigned to Jibaissodes according to the following diagnostic characters: forewing vein 1r-rs present, shorter than 2r-rs, cell 2rm longer than 3rm and cell 1mcu small. Jibaissodes was described from a poorly preserved fossil specimen with a left and a right forewing, a right hind wing, and parts of head and thorax ( Ren et al. 1995). Jibaissodes peichenae sp. nov. is distinctly differentiated from the type species of J. giganteus by the following characters: forewing with pterostigma not completely infuscated; forewing vein 3r-m distinctly longer than 2r-m (about 1.7 times as long as 2r-m); 1cu-a distinctly curved; and hind wing vein 1-Rs nearly equal to 1r-m. Furthermore, J. peichenae is distinguished from J. bellus by the following characters: antenna pectinate, rami short (vs rami long in J. bellus ); forewing with pterostigma infuscated apically (vs infuscated medially and apically in J. bellus ).

Distribution.

Huangbanjigou, near Chaomidian Village, in Shangyuan County, adjacent to Beipiao City, in Liaoning Province of China. Collected from the mid-Lower Cretaceous Yixian Formation, dated as latest Barremian to earliest Aptian, 125 Ma ( Ren et al. 1995; Wang et al. 2015).

Etymology.

The species epithet is dedicated to Miss Peichen Yao, the daughter of Dr Jun Yao, the specimen donator.

Figures

Figure 1. A-D Jibaissodes peichenae sp. nov., holotype, part: A photograph of complete specimen B line drawing of complete specimen C line drawing of forewing D line drawing of hind wing E, F Jibaissodes giganteus, holotype: E line drawing of forewing F line drawing of hind wing. Scale bars: 2 mm (A, B), 1 mm (C-F).

Figure 2. A-E Jibaissodes peichenae sp. nov., holotype, part: A head B basis of left antenna C basis of right antenna D right antenna E basal to middle section of right antenna F, G Jibaissodes bellus, holotype: F right antenna G apical portion of right antenna. Abbreviations: md = mandible, sc = scape, ped = pedicel, oc = ocelli, 1 st fla = 1 st flagellomere, N 1 = pronotum, psc 2 = mesoscutum. Scale bars: 1 mm (A, D, F, G); 0.5 mm (B, C, E).

Figure 3. Jibaissodes peichenae sp. nov., holotype, counterpart A complete specimen B right hind leg C left hind leg. Arrows indicate spurs. Scale bars: 2 mm (A); 1 mm (B, C).