Megalavini, 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. Tribe † Megalavini trib. nov.

Type genus.

† Megalava Perrichot, 2009.

Diagnosis.

Mandible with three teeth, decreasing in size from apex to base; occipital carina crenulate. Pronotum not visible dorsally; mesometapectal sulcus (sensu Vilhelmsen et al. 2010b) crenulate. Fore wing venation most complete within Megalyridae ; pterostigma reduced; C, M+Cu, Sc+R, A and M almost fully pigmented; R1 extending beyond marginal cell; marginal cell closed by Rs in straight line; Rs present between r-rs and Rs+M, closing first submarginal cell; M+Cu aligned with Rs+M; medial cell rectangular or trapezoidal, located under Rs+M and closed by 1m-cu and basal segments of Cu and Cu1. Metasoma elongate, with long to very long ovipositor (OL/BL ~ 0.40).

Genera and species included.

† Megalava truncata Perrichot, 2009, † Cretolyra noijebumensis gen. et sp. nov., † Cretolyra shawi gen. et sp. nov., † Genkyhag innebula gen. et sp. nov., † Megacoxa chandrahrasa gen. et sp. nov., † Megacoxa janzeni gen. et sp. nov., † Megacoxa synchrotron gen. et sp. nov.

Comments.

The † Megalavini trib. nov. retain a plesiomorphic fore wing venation (i.e., the most complete wing venation among megalyrids sensu stricto) as a key character with C, Sc+R, M+Cu, A, Rs+M, Cu, R1, Rs and M almost fully pigmented (Figs 2A-F ). The main synapomorphy for this clade is the form of the medial cell, which is rectangular due to alignment of Rs+M with M+Cu (Figs 2A-F ). Comprising exclusively Cretaceous taxa, † Megalavini trib. nov. also display an anterior thoracic spiracle that is not fully surrounded by pronotal cuticle (Fig. 3D ), which we consider to be the second diagnostic feature (despite being plesiomorphic) for the tribe. When described, the monospecific genus † Megalava was stated to belong to the tribe † Megazarini with † Megazar , and this has been confirmed in Vilhelmsen et al. (2010a). However, based on the description of a new complete specimen ( Pérez-de la Fuente et al. 2012: fig. 2B), we propose to transfer † Megalava to the new tribe, due its more complete wing venation, the rectangular medial cell, the crenulate mesometapectal sulcus and the mandible configuration (three teeth while † Megazar has four).

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 3. † Cretolyra noijebumensis gen. et sp. nov., holotype male IGR. BU- 067, mid-Cretaceous, Kachin amber. A habitus in lateral view; B head and mesosoma in dorsal view; C fore wing; D anterior part of mesosoma in lateral view with structures outlined; E metasoma and posterior part of the mesosoma in lateral view. Scale bars: 0.5 mm (A, B, C, E); 0.25 mm (D). Abbreviations: AG = inner axillar groove; MeS = mesometapectal sulcus; MMS = median mesoscutal sulcus; OC = occipital carina; PpL = parapsidal line; sp = anterior thoracic spiracle.