Megacoxa brazideci, Vilhelmsen & Wu & Wang & Gao & Ren, 2025

† Megacoxa brazideci sp. nov.

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Fig. 2 View Fig

Diagnosis

Body comparatively slender ( Fig. 2A View Fig ), metasoma longer than mesosoma (shorter in † M. chandrahrasa Brazidec et al., 2024 and † M. gungner sp. nov.). Head with transverse striae on frons ( Fig. 2B View Fig ). Antennae longer than head + mesosoma combined. Median mesoscutal sulcus smooth (crenulate in † M. synchrotron Brazidec et al., 2024 ), axillae contiguous (not contiguous in † M. janzeni Bracidec et al., 2024 and † M. mjoelner sp. nov.). Hind coxa without carina and foveae along posterior margin (coxa carinate and foveate in † M. janzeni and † M. synchrotron ). Ovipositor elongate, longer than body ( Fig. 2A View Fig ).

Etymology

The new species is named after Manuel Brazidec, the French palaeoentomologist who described † Megacoxa as well as a number of other extinct wasp taxa.

Type material

Holotype

MYANMAR • ♀; Kachin State, Myitkyina District, Hukawng Valley ; [26°20′ N, 96°36′ E]; unnamed horizon, mid-Cretaceous, upper Albian to lower Cenomanian, 98.79± 0.62 Ma ( Cruickshank & Ko 2003; Shi et al. 2012); CNU-HYM-MA-2016210 . GoogleMaps

Description

Female

BODY. Length (except ovipositor) 3.7 mm, fore wing length 2.6 mm, ovipositor length 4.3 mm. Specimen complete, generally well preserved (left hind femur and tibia somewhat compressed), in clear amber piece with few and small air bubbles, no major occlusions obscuring specimen, anterior part of head covered with thin milky film.

HEAD. Oval in lateral view, wider than long, eyes oval, occupy most of lateral surface of head ( Fig. 2B View Fig ); ocelli situated on top of head in approx. equilateral triangle; frons with transverse, wavy striation; postocular carina absent; occipital carina well developed, smooth, slightly incurved dorsally, area around occipital foramen deeply concave; antennae slender, elongate, longer than combined length of head + mesosoma, scapus short, expanded distally, short pedicellus inserted subapically on scapus, antennomeres 4 and 5 longest ( Fig. 2B View Fig ), antennomeres gradually shortening until apical antennomere, which is approx. 2× as long as penultimate antennomere; mandibles with three teeth each; short, slender palps observed.

MESOSOMA. With elongate, extended propectus ( Fig. 2D View Fig ); pronotum narrow medially, triangular laterally, with anterior thoracic spiracle in notch in lateral margin; fore femur slender, fore tibia slightly expanded distally, with elongate, curved calcar; mesoscutum strongly arched in lateral view, vertical anterior surface curves smoothly into horizontal surface; horizontal surface flat, level with mesoscutellum, not prominently sculptured; median mesoscutal sulcus distinct, apparently smooth, extends to transscutal articulation; axillae distinct, triangular, continuous medially, separated from mesoscutellum by curved foveate scutoscutellar sulcus ( Fig. 2C View Fig ); mesoscutellum flat, smooth with small punctures, triangular posteriorly; mesopleuron smooth, with depression medially, mesopleuro-metapleural sulcus distinct, crenulate; mid femur slightly spindle-shaped, mid tibia slender, with two short apical spurs; hind coxa broad basally, cone-shaped, without carina or foveae along posterior margin; hind femur spindle-shaped, broadened in middle; hind tibia flattened, expanded distally, without fringe of setae, with two apical spurs of subequal length ( Fig. 2A View Fig ), inner spur approx. to distal tibial width of tibia; hind basitarsus with short erect pegs on inner side, of approx. same length as remaining tarsomeres, tarsal claws simple, slender.

WINGS. Fore wing hyaline with veins C, R1, Sc+R, M+Cu, A, Rs+M, Rs, M and Cu fully pigmented; Rs+M aligned with M+Cu; medial cell wide distally, rectangular; Rs present between Rs+M and r-rs, closing first submarginal cell; marginal cell narrow, closed in straight line by Rs; hind wings mostly covered by fore wings, apparently with little venation developed.

METASOMA. 1.12 × as long as mesosoma, slender, fusiform, without prominent sculpture or pilosity; metasomal segment 2 largest, metasoma widest there, sternum 2 with concavities for accommodating hind coxae; slender, slightly swollen cerci extend from tip of metasoma ( Fig. 2C View Fig ); sternum 7 tapered apically, folded over medially along longitudinal axis; ovipositor extending posteriorly, elongate, length 1.16 × body length ( Fig. 2A View Fig ), ovipositor proper and sheaths slender, tip of 2 nd valvula with 6–7 small dorsal teeth.

Male

Unknown.

Remarks

† Megacoxa brazideci sp. nov. can be most easily recognized by the transverse striae on the frons and the elongate antennae; the ovipositor is also longer than in most other species of the genus. The frontal sculpture might help facilitate eclosion from a pupal chamber in wood; many other wood-living wasps have prominent sculpture on the head or mesosoma for this purpose ( Turrisi & Vilhelmsen 2010; Vilhelmsen & Turrisi 2011). The species resembles † M. mjoelner sp. nov. in having the median sulcus smooth and the hind coxa without carina and foveae posteriorly, but differs in having the axillae contiguous.