Allobethylus biconcavus Azevedo, 2005

Azevedo, C. O., 2005, A new species of Allobethylus (Hymenoptera: Bethylidae) from Australia, with a key to world species, Zootaxa 1064, pp. 25-30 : 26-28

Allobethylus biconcavus Azevedo , New Species

Diagnosis. Mandibles very long, tetradentate. Ocellar triangle very compact and distant from vertex crest. Notauli and parapsidal furrows nearly complete. Forewing well developed, radius tubular and long. Propodeal disc with strong emarginations on lateral margins.

Description of Female. Length. Body 3.33 mm; forewing 2.15 mm.

Color. Head and mesosoma dark castaneous, metasoma and front coxae somewhat dark castaneous, mandibles, antennae, palpi, tegulae and legs castaneous, wings subhyaline, stigma and veins castaneous.

Head ( Fig. 1 ). Mandibles very long, overlapping more than apical half of opposite mandible; with four apical teeth, two upper teeth very short and blunt, two lower teeth large and sharpened, three upper teeth nearly fused and forming concave edge; dorsal margin of mandible slightly convex in distal half; ventral margin of mandible slightly concave for long distance and with rounded lobe at middle ( Fig. 2 ). Clypeus very short, slightly extending backward into frons; median area of clypeus elevated; apical margin emarginated. First 4 antennal segments in ratio of ~10:5:3:3, segment 3 longer than wide, segment 11 barely wider than long. Pubescence of antenna suberect, with some erect setae also present. Eyes ovoid, setose. Frons coriaceous, with dense small punctures and with shallow narrow median line extending from basal margin of clypeus to basal third of length eye. WH 0.72X LH, WF 0.44X WH, WF 0.77X HE, ocellar triangle very compact, OOL 2.11X WOT, frontal angle of ocellar triangle acute, posterior ocelli distant from vertex crest 3.6X DAO. Vertex narrowly convex with broadly rounded corners. Temples parallel, head rectangular in dorsal view. Occipital carina very weak. Palpal formula 6:3.

Mesosoma ( Fig. 3 ). Thorax coriaceous and punctated as frons. Pronotal disc without anterior carina, anterior corners slightly angled. Notauli and parapsidal furrows nearly complete and well impressed; notauli converging posteriorly; parapsidal furrows parallel. Scutellar groove conspicuous, narrower medially, ends slightly dilated and curved backward. Lateral faces of propodeum coriaceous, strongly emarginated medially, so that propodeal disc strongly bi­concave in dorsal view; disc as long as its posterior width and 1.7X as long as its median width; median carina weak and present only in anterior half; anterior half with weak striae; posterior half finely transversely strigulate, lateral and posterior carina present; declivity coriaceous with median carina. Forewing well developed, stigma small, radius long, without metacarpus, transverse­median vein curved and slightly oblique. Medial area of mesopleuron slightly depressed transversely with rounded, small central pit. Front femur 2.33X as long as thick. Middle tibia spinose. All claws simple.

Metasoma. Sessile, subcircular in cross section; polished basally, very weakly coriaceous apically; last sternite with strongly “V”­shaped suture in anterior margin and strongly setose apically. Valvae setose apically.

Material examined. Holotype: male, Aust[ralia], Q[ueens]l[an]d, Mount Glorious, 27º19'54" S 152º45'29" E, 29.XI–5.XII.1997, Malaise [trap] 3, T. Hiller col. ( ANIC).

Comments. Allobethylus biconcavus and A. tomoae are the only two species of Allobethylus with the mandible tetradentate. Their mandibular morphology differs, however, with A. biconcavus having the two upper teeth wide, blunt and very closed to each other, whereas A. tomoae has these teeth narrow, sharpened and distinct. The genus is recorded for the first time to Australia. This new record expands the known distribution of Allobethylus and suggests that the genus is more widely distributed than previously though. This genus is likely found throughout Polynesia and Micronesia, based on the distribution of A. tomoae , which is from Japan, and A. ewa , which is from Hawaii.

Etymology. The specific epithet refers to the strong concave lateral margins of propodeal disc.

Figures

FIGURES 1 – 3. Allobethylus biconcavus sp. nov. 1. Head in dorsal view; 2. Mandible in frontal view; 3. Mesosoma in dorsal view.