Megacoxa chandrahrasa, Brazidec & Vilhelmsen & Boudinot & Richter & Hammel & Perkovsky & Fan & Wang & Wu & Wang & Perrichot, 2024

Brazidec, Manuel, Vilhelmsen, Lars, Boudinot, Brendon E., Richter, Adrian, Hammel, Joerg U., Perkovsky, Evgeny E., Fan, Yong, Wang, Zhen, Wu, Qiong, Wang, Bo & Perrichot, Vincent, 2024, Unveiling ancient diversity of long-tailed wasps (Hymenoptera: Megalyridae): new taxa from Cretaceous Kachin and Taimyr ambers and their phylogenetic affinities, Arthropod Systematics & amp; Phylogeny 82, pp. 151-181 : 151

3.1.1.3.1. † Megacoxa chandrahrasa sp. nov.

Figures 2D , 6

Etymology.

The specific epithet is a noun in apposition. It is the name of the legendary sword of Mañjuśrī, a bodhisattva in Buddhism, which allowed him to open the Kathmandu valley, and refers to the long, sword-like metatibial spurs of this species.

Material studied.

Holotype female IGR.BU-068; housed in the amber collection of the Geology Department and Museum of the University of Rennes, France (IGR) . Paratype female CNU-HYM-MA2016207; housed in the Key Lab of Insect Evolution and Environmental Changes , College of Life Sciences, Capital Normal University, Beijing, China (CNU) .

Type locality.

Noije Bum Hill, Hukawng Valley, Kachin State, Myanmar.

Age.

Upper Albian to lower Cenomanian, mid-Cretaceous.

Diagnosis.

Median mesoscutal sulcus smooth (Fig. 6F ; vs. crenulate in Megacoxa synchrotron gen. et sp. nov.); axillae contiguous medially (Fig. 6A ; vs. separated medially in Megacoxa janzeni gen. et sp. nov.); medial cell elongate, almost triangular (Figs 2D and 6A ; vs. broad and rectangular in Megacoxa synchrotron gen. et sp. nov. and Megacoxa janzeni gen. et sp. nov.); posterior margin of metacoxa outcurved and bordered with small foveae (Fig. 6C ; vs. bordered with large foveae in Megacoxa janzeni gen. et sp. nov. . and straight posterior metacoxal margin with large foveae in Megacoxa synchrotron gen. et sp. nov.); metatibial spurs very long (Figs 6A, B and G ); metasoma compressed, distinctly shorter than ovipositor; OL/BL ratio ~0.70.

Description.

Body length for holotype 2.64 mm; for paratype 4.80 mm. - Head globular, higher than long (length for holotype 0.52 mm; for paratype 0.93 mm), glabrous; frons convex, shagreened; compound eye oval, higher than long; vertex convex; clypeus short, shagreened; toruli inserted closer to each other than to eyes; subantennal groove present; antennae distorted, flagellomeres apparently cylindrical, longer than wide; occipital carina crenulate. - Mesosoma more than half body length (length for holotype 1.43 mm; for paratype 1.92 mm); covered with short setae; mesoscutum convex, wide (length for holotype 0.62 mm, width for holotype 0.74 mm; length for holotype 0.93 mm, width for holotype 0.90 mm), divided by smooth median mesoscutal sulcus; parapsidal lines present; axillae contiguous medially, inner axillar groove crenulate; pronotum not visible dorsally; anterior thoracic spiracle not fully surrounded by pronotal cuticle; mesometapectal sulcus crenulate; propodeum shorter than mesoscutellum, carinate. - Fore wing hyaline and covered with microtrichiae, slightly wrinkled at apex, as long as body (length for holotype 2.08 mm; for paratype 3.52 mm); venation complete with R1, M+Cu, Sc+R, Rs, A and Cu fully pigmented; Rs closing marginal cell; medial cell elongate; A connected to medial cell by 1cu-a. - Legs distorted; two mesotibial spurs; metacoxa huge, almost as high anteriorly as maximal propodeal height, with dorsal surface semicircular, posteroventral corner acute, ventral surface notched just anteriad trochanter insertion; outer metacoxal surface posteriorly with row of small foveae; dense row of short, comb-like setae along ventral surface of metatrochanter (full length), metafemur (basal half length), metatibia (distal half length), and metabasitarsus (full length); metafemur swollen; two long metatibial spurs, about twice as long as maximal tibial width; metabasitarsus three to four times longer than following metatarsomeres. - Metasoma relatively short (length for holotype 1.21 mm; for paratype 1.95 mm), distorted, partly intruding into propodeum during fossilization; tergites and sternites inserted in bevel, smooth; ovipositor longer than metasoma (length for holotype 1.87 mm, OL/BL ratio 0.70; length for paratype 3.24 mm, OL/BL ratio 0.68), sheaths transversely striated.

Comments.

We first interpreted the very high OL/BL ratio of the holotype of † Megacoxa chandrahrasa gen. et sp. nov. compared to other † Megalavini (0.70 vs. ~0.40) as a distortion of the specimen and the intruding of the metasoma into the mesosoma. However, the discovery of an additional specimen confirms that the metasoma is more compact in this species than in other species of the genus or the subfamily.

Figures

Figure 2. Drawings of fore wing venation for the taxa described in the present paper. A † Cretolyra noijebumensis gen. et sp. nov.; B † Cretolyra shawi gen. et sp. nov.; C † Genkyhag innebula gen. et sp. nov.; D † Megacoxa chandrahrasa gen. et sp. nov.; E † Megacoxa janzeni gen. et sp. nov.; F † Megacoxa synchrotron gen. et sp. nov.; G † Kamyristi exfrigore gen. et sp. nov.; H † Kamyristi yantardakhensis gen. et sp. nov. Scale bars: 0.5 mm (A - H).

Figure 6. † Megacoxa chandrahrasa gen. et sp. nov., mid-Cretaceous, Kachin amber. A holotype female IGR. BU- 068, habitus in dorsal view; B habitus in lateral view; C mesosoma in lateral view; D head in frontal view; E paratype female CNU-HYM-MA 2016207, habitus in lateral view; F head and mesosoma in dorsolateral view; G hind legs; H ovipositor and its sheaths. Scale bars: 1 mm (A, B, E, F); 0.5 mm (C, D, G, H). Abbreviations: Cx = hind coxa; MeS = mesometapectal sulcus; MMS = median mesoscutal sulcus; OC = occipital carina; PpL = parapsidal line; sp = anterior thoracic spiracle.