Siccibythus aristovi Wang, Rasnitsyn, Perkovsky & Vilhelmsen, 2025

Wang, Zhen, Rasnitsyn, Alexandr P., Perkovsky, Evgeny E., Vilhelmsen, Lars & Gao, Taiping, 2025, New wasps of † Falsiformicidae from mid-Cretaceous Kachin amber, Journal of Hymenoptera Research 98, pp. 1-18 : 1-18

Siccibythus aristovi Wang, Rasnitsyn, Perkovsky & Vilhelmsen sp. nov.

Diagnosis.

Fore wing with 2 Rs distal of r-rs at most about as long as r-rs; Rs + M and Cu both nebulous; A behind 1 cu-a not pigmented (except for very base). Fore tibial spur short, bifid apically. Basitarsus not longer than tarsomeres 2–4 combined. Pronotum short, propodeal horns long.

Etymology.

The specific name “ aristovi ” is dedicated to the memory of the late Dr. Daniil Sergeevich Aristov, for his outstanding contribution to palaeoentomology.

Type material.

Holotype • female. No. CNU-HYM-MA 2016214 . A well-preserved and complete specimen (Figs 5 , 6 ) .

Type locality and horizon.

The amber specimen was collected from Kachin, northern Myanmar, lowermost Cenomanian, mid-Cretaceous, which was dated at 98.79 ± 0.62 Ma ( Cruickshank and Ko 2003; Shi et al. 2012).

Description.

Female. Body brown, metasoma dark brown. Head globose, with eyes bulging, occupying three-quarters of head in lateral view, almost reaching mandibular bases, occipital carina complete, reaching hypostomal carina well behind mandibular base, ocelli in small acute triangle well distant from eyes, interantennal space flat. Antenna narrow, with 12 antennomeres, each antennomere is approximately 1–2 times longer than wide, scape shorter than pedicel, pedicel longer than first flagellomere, flagellomeres slightly shortening gradually toward apex except for longer apical segment (Fig. 6 A ). Mandibles with three teeth, not overlapping; labrum not visible; maxillary palp short with six elongate palpomeres, labial palp short, with four slightly elongate to subquadrate palpomeres (Fig. 6 B ).

Pronotum with long dorsal part shorter than wide before lateral lobes, constricted near midlength, with fore declivitous part short, delimited by transverse groove posteriorly. Propleura long, slender, in lateral view, the length is 4 times its width, and abutting throughout. Mesoscutum with deep notauli widely spaced anteriorly, converging to almost meet posteriorly; transscutal articulation distinct; mesoscutellum rather short, wide apically, weakly convex. Meso- and metapleurae smooth. Metanotum short, with metascutellum very short and wide. Propodeum with dorsal and posterior surfaces meeting in angle, dorsal with longitudinal carina, and with transverse one midway between sublateral carinae, posterior surface with lateral longitudinal carinae, sublateral longitudinal carinae and supracoxal transverse carinae (Fig. 6 C, D ).

Fore wing basal veins (C, Sc + R, M + Cu, A, 1 Rs and 1 M), r-rs, short pterostigma, part of 2 Rs distal of r-rs and cu-a tubular, other veins nebulous. Pterostigma prominent, longer than wide; vein 1 Rs straight, shorter than 1 M, arise from Sc + R just proximal to pterostigma; 1 cu-a shorter than 1 M, parallel to 2 cu-a, placed slightly basally of 1 M; 1 Cu parallel to A; vein A extends distal up to 1 cu-a only; r-rs straight, arising beyond midlength of pterostigma; r-m not present (Fig. 6 E ). Hind wing with Sc + R; other veins not visible.

Fore trochanter present, fore trochantellus ring-like; fore femur slightly swollen in middle, nearly three times as long as wide; fore tibia shorter than femur, calcar acute (not bifid); fore tarsus shorter than fore tibia, basitarsomere shorter than combined length of remaining tarsomeres. Mid trochanter present, mid trochantellus ring-like; mid femur slightly swollen in middle, four times as long as wide; mid tibia nearly as long as femur, six times as long as wide; mid tarsus shorter than mid tibia, basitarsomere shorter than combined length remaining tarsomeres. Hind trochanter short, bulging dorsally, hind trochantellus ring-like; hind femur slightly swollen in middle, nearly four times as long as wide; hind tibia slender than femur, longer than femur; hind tarsus nearly as long as hind tibia, remaining tarsomeres combined shorter than basitarsomere. Claw simple, arolium small. Tibial spur formula 1 / 2 / 2.

First metasomal segment short, tergum node-like, triangular in lateral view, with anterior surface concave, second segment slightly longer and higher than following, following gradually smaller, apical (sixth) sternum high, apparently folded, with upper sides and apical orifice apparently not specialized, tergum 7 as visible (in lateral view) small but more or less sclerotized, with spiracle not enlarged (Fig. 6 F ). Sting straight, apparently short, without teeth.

Measurements (mm).

Holotype female. Total body length (excluding sting and antenna) 4.14; head length 0.94, width 0.62, height 0.48; scape length 0.20, pedicel length 0.19, the first flagellum length 0.14, total flagellum length 1.11; fore wing length 1.95; hind wing length 1.20; fore coxa length 0.27, fore trochantellus 0.06, fore femur length 0.64, fore tibia length 0.49, fore tarsal length 0.64; mid coxa length 0.25, mid trochanter length 0.10, mid trochantellus 0.04, mid femur length 0.60, mid tibia length 0.64, mid tarsal length 0.39; hind coxa length 0.23, hind trochanter length 0.10, hind trochantellus 0.06, hind femur length 0.69, hind tibia length 0.58, hind tarsal length 0.79; the first metasomal segment length 0.29, metasoma length 1.66.

Remarks.

The new species is classified in † Siccibythus Cockx & McKellar, 2016 based on the fore wing with no cells closed with tubular veins in its middle and distal part ( Rasnitsyn et al. 2020). It is differentiated from Siccibythus musculosus , S. paulus , S. ohmkuhnlei and S. robustus by fore wing with 2 Rs distal of r-rs shorter than r-rs, basitarsus not longer than tarsomeres 2–4 combined (vs. 2 Rs distal of r-rs several times as long as r-rs, basitarsus longer than tarsomeres 2–4 combined in S. musculosus , S. paulus , S. ohmkuhnlei and S. robustus ). It is distinguished from S. martynovae by fore wing veins Rs + M and Cu both being nebulous (vs. Rs + M and Cu are both tubular in S. martynovae ). It is differentiated from S. pallidus by the following characters: 1) fore wing with 2 A not pigmented (except for very base) (vs. fore wing with 2 A pigmented); 2) pronotum constricted in the middle (vs. not constricted). It is distinguished from S. oculatus by pronotum short, propodeal horns long (vs. pronotum long, propodeal horns short).

Figures

Figure 5. Photographs of Siccibythus aristovi sp. nov. (Female holotype; CNU-HYM-MA- 2016214) A habitus in dorsal view B habitus in lateral view.

Figure 6. Photographs of Siccibythus aristovi sp. nov. (Female holotype; CNU-HYM-MA- 2016214) A head in lateral view B mouthparts C mesosoma in lateral view, black arrow indicates the carinae D mesosoma in dorsal view E fore wing venation F metasoma in lateral view.