Megaprosternum pentagonal Azevedo, 2006

Colombo, Wesley D. & Azevedo, Celso O., 2024, Revision of the strongly flattened Megaprosternum Azevedo (Hymenoptera, Bethylidae), European Journal of Taxonomy 958 (1), pp. 1-47 : 33-35

Megaprosternum pentagonal Azevedo, 2006

Megaprosternum pentagonal Azevedo, 2006: 40–42 .

Megaprosternum pentagonal – Gupta et al. 2017: 89. — Azevedo et al. 2018: 235.

Differential diagnosis

The males of this species differ from those of the other species by having the head about 1.2× as long as wide, with the sides converging posterad, in dorsal view, the median clypeal lobe with lateral carinae parallel or subparallel posteriorly, the antennae with 11 flagellomeres, ocelli distant each other about 0.5× DAO, the postocellar line almost shorter than DAO, the propodeal spiracles on lateral surface of the metapectal-propodeal complex, the hypopygium with spiculum narrowing apicad and, the aedeagal apex aligned to cuspis apex. The females of this species differ from those of the other species by having the antennae with 11 flagellomeres and the wings very reduced, shorter than tegulae (micropterous form).

Material examined

Holotype

AUSTRALIA – Queensland • ♂; “ Queensland, Mount Glorious , 27º19’54”S 152º45’29”E, 29.XI–5. XII.1997, Malaise trap 3, T. Hiller col”; ANIC.

Allotype

AUSTRALIA – Queensland • ♀; same data as for holotype, except “ 630 m, dry sclerophyll Eucalyptus forest, S.F., 28.II–9.III.1984, L. Masner col”; ANIC.

Redescription

Male

MEASUREMENTS (mm). Body length 2.56 mm; LH 0.46; WH 0.40; WF 0.22; WOT 0.09; surface of median clypeal lobe 0.12; HE 0.19; OOL 0.19; LFW 1.59.

COLOR. Head and mesosoma black, metasoma dark castaneous.

HEAD. Oval, in lateral view; sides almost parallel, in dorsal view; malar space 0.2 × HE; median clypeal lobe straight, as long as lateral ones, with pair of lateral carinae, parallel posteriorly, lobe delimitation distinct; mandible with three apical teeth; antenna with 11 flagellomeres, pedicel longer than flagellomere I; eye glabrous, contour not protruding; frons coriaceous; ocellar triangle with anterior angle obtuse, postocellar line shorter than DAO.

MESOSOMA. Pronotal flange polished, with posterior margin at most 1.5× as wide as anterior one; dorsal pronotal area coriaceous, posterior margin almost straight; probasisternum very large, anterior margin strongly angulated, posterior margin almost straight; epicnemium with anterior margin weakly incurved; mesoscutum almost as long as mesoscutellum medially; parapsidal signum absent; transscutal fissure inconspicuous; mesoscuto-scutellar suture absent; mesopleuron with mesopleural pit present; metapectal-propodeal disc almost as long as wide medially, without evident constriction at propodeal spiracle; transverse anterior carina absent; lateral marginal carina absent; paraspiracular sulcus absent; paraspiracular carina absent; metapostnotal median carina absent; propodeal spiracle oval, on lateral surface of the metapectal-propodeal complex; forewing with prestigmal abscissa of radial 1 triangular; 2.0× as long as pterostigma; 3.0× as wide as Sc+R vein; prestigmal flexion line present; pterostigma small and oval.

METASOMA. Second abdominal spiracle circular; abdominal tergum narrowing apicad; hypopygium with spiculum narrowing apicad, hypopygeal anterolateral apodeme present, hypopygeal posterior margin straight. Genitalia with harpe 2.5 × as long as gonostipes; digitus with posterior margin smooth; aedeagal apex aligned to cuspis apex.

Female

MEASUREMENTS (mm). Body length 3.92 mm; LH 0.51; WH 0.41; WF 0.25; WOT 0.07; surface of median clypeal lobe 0.05; HE 0.20; OOL 0.29.

COLOR. Head, mesosoma and metasoma dark castaneous.

HEAD. Rectangular, in lateral view; sides almost parallel, in dorsal view; malar space 0.2× HE; median clypeal lobe straight, as long as lateral ones, without pair of lateral carinae, lobe delimitation indistinct; mandible with three apical teeth; antenna with 11 flagellomeres, pedicel longer than flagellomere I; eye weakly setose, contour not protruding; frons coriaceous; ocellar triangle with anterior angle acute, postocellar line longer than DAO.

MESOSOMA. Pronotal flange polished, with posterior margin at least 1.6× as wide as anterior one; dorsal pronotal area polished and coriaceous, posterior margin almost straight; probasisternum very large, anterior margin strongly angulated, posterior margin almost straight; epicnemium with anterior margin almost straight; mesoscutum almost as long as mesoscutellum medially; parapsidal signum absent; transscutal fissure inconspicuous; mesoscuto-scutellar suture absent; mesopleuron with mesopleural pit present; metapectal-propodeal disc longer than wide medially, with evident constriction at propodeal spiracle; transverse anterior carina absent; lateral marginal carina absent; paraspiracular sulcus absent; paraspiracular carina absent; metapostnotal median carina absent; propodeal spiracle oval, on lateral surface of the metapectal-propodeal complex; micropterous with tegulae present.

METASOMA. Abdominal tergum narrowing apicad.

Variations

Males are macropterous, along with a short clypeus projecting beyond the anterior margin of the antennal rim, and the head with sides converging posterad. In contrast, females exhibit a greatly reduced wings (micropterous form), characterized by the shorter clypeus than the anterior margin of the antennal rim, the head rectangular, and the profemur thicker than those of males.

Remarks

This species was described from two specimens (one male and one female) collected in Queensland, Australia. Although Azevedo (2006) did not explicitly detail the method of associating the two strongly dimorphic sexes (micropterous female and macropterous male), it can be inferred from the author’s statement: “The shape of the antenna, mandible teeth, ocellar triangle, and mesosoma are very similar in both sexes, but sexual dimorphism is strong”. The author likely linked them based on morphological similarities and the specimens’ common type-locality. Azevedo (2006) initially described the female of this species as apterous. However, upon further review, it became apparent that there is a wing, albeit highly reduced, leading to the consideration that the females of this species are micropterous.

Host

Unknown.

Distribution

Australia (Queensland).