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

† Megacoxa mjoelner sp. nov.

urn:lsid:zoobank.org:act:215840BF-F89F-4A1B-98F1-A738E89B3299

Fig. 4 View Fig

Diagnosis

Body comparatively slender ( Fig. 4A View Fig ), metasoma longer than mesosoma (shorter in † M. chandrahrasa and † M. gungner sp. nov.). Antennae shorter than head + mesosoma (longer in † M. brazideci sp. nov.). Median mesoscutal sulcus smooth (crenulate in † M. synchrotron ), axillae not contiguous (contiguous in † M. brazideci ). Hind coxa without carina or foveae along posterior margin (coxa carinate and foveate in † M. janzeni and † M. synchrotron ).

Etymology

The new species takes its name after Mjølner (or Mjolnir), the magic hammer that was the chief weapon and primary attribute of Thor, the thunder god in Norse mythology. Like the ovipositor in † M. mjoelner sp. nov. (see below), the shaft of the hammer was shorter than it was originally supposed to be, due to the interference of the trickster god Loke in the form of a fly; he viciously stung the dwarven smith Brokk as Mjølner was being finalized, thus confirming the timeless malevolence of Diptera.

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-2016209 . GoogleMaps

Description

Female BODY. Length (except ovipositor) 4.3 mm, fore wing length 3.3 mm, ovipositor length 1 mm as preserved ( Fig. 4A View Fig ), probably broken (see below). Specimen in mostly clear amber piece, with small midge (Diptera) syninclusion. Exudate covers lower part of head and a few diffraction planes extend from dorsal part of mesosoma.

HEAD ( Fig. 4D View Fig ). Globular, slightly wider than long, without prominent sculpture or setation; eyes oval, cover most of lateral surface of head; ocelli situated on top of head in approx. equilateral triangle; postocular carina absent; occipital carina well developed ( Fig. 4D View Fig ), smooth, area around occipital foramen deeply concave; antenna clearly shorter than head + mesosoma combined, scapus curved, pedicellus short, antennomeres 3–13 cylindrical ( Fig. 4D View Fig ), slightly longer than wide, decreasing in length distally, antennomere 14 approx. twice as long as wide, tapering distally; mouthparts difficult to observe, mandible apparently broad, teeth not visible; short palps can be observed.

MESOSOMA. With elongate, extended propectus; pronotum narrow medially, triangular laterally, with anterior thoracic spiracle in notch in lateral margin ( Fig. 4C View Fig ); fore femur spindle-shaped, fore tibia slightly expanded distally ( Fig. 4D View Fig ), with elongate, curved calcar; mesoscutum strongly arched in lateral view, angled between vertical anterior surface and horizontal surface; horizontal surface flat, level with mesoscutellum, not prominently sculptured; median mesoscutal sulcus distinct ( Fig. 4B–C View Fig ), smooth, extends to transscutal articulation; axillae distinct, triangular, not abutting medially, separated from mesoscutellum by oblique foveate scutoscutellar sulcus; mesoscutellum flat, smooth with small punctures, diamond-shaped; mesopleuron smooth, with depression medially, mesopleuro-metapleural sulcus distinct, crenulate ( Fig. 4C View Fig ); mid femur spindle-shaped, mid tibia slender, with two short apical spurs; hind coxa broad, with carina along posterior margin but without foveae; hind femur spindle-shaped; hind tibia ( Fig. 4A View Fig ) flattened, expanded distally, without fringe of setae, with two apical spurs of subequal length, inner spur shorter than distal tibial width; hind basitarsus slightly longer than remaining tarsomeres, tarsal claws simple, slender.

WINGS. Fore wing ( Fig. 4B View Fig ) 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; Rs present between Rs+M and r-rs, closing first submarginal cell; marginal cell narrow, closed in straight line by Rs; hind wing could not be observed.

METASOMA ( Fig. 4A View Fig ). 1.27 × as long as mesosoma, slender, fusiform, without prominent sculpture or pilosity; metasomal segment 2 largest, metasoma widest there; sternum 7 tapered apically, folded over medially along longitudinal axis; ovipositor ( Fig. 4A View Fig ) bent ventrally, apparently broken, 1 st and 2 nd valvulae separated at tip and no teeth observed on tip of 2 nd valvula.

Male

Unknown.

Remarks

† Megacoxa mjoelner sp. nov. mostly resembles † M. brazideci sp. nov., from which it differs in having a smooth frons, shorter antennae and the axillae not being contiguous.