Malayepipona fincta, Lien, 2020

Lien, Nguyen Thi Phuong, 2020, Two new species of the genus Malayepipona Giordani Soika (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with updated key to all recognised species, Raffles Bulletin of Zoology 68, pp. 112-117 : 114-116

Malayepipona fincta , new species

( Figs. 8 –15)

Material examined. Holotype: male (deposited in IEBR), labelled “ VIETNAM, Dak Lak, Krong Bong, Krong Kmar, Chu Yang Sing NP, 12°25′02.8″N, 108°22′30.8″E, alt. 1081 m, 4.v.2016, Nguyen Thi Phuong Lien, Tran Thi Ngat”.

Diagnosis. This species can be distinguished from all other known species of the genus Malayepipona by the following combination of features: pronotal carina strongly produced at humeral angles; tegula with posterior lobe long and much exceeding the posterior end of parategula; forewing with a dark spot at apex of marginal cell; and metasomal segments dull, tergum I with partial transverse carina at base which is visible at lateral sides, terga II–VI without apical lamella.

Description. Male. Body length 8.3 mm; forewing length 8.0 mm. Head in frontal view subcircular, about 1.3 times as wide as high. Vertex without cephalic foveae. Distance from posterior ocelli to apical margin of the vertex about 1.5 times of the distance from posterior ocelli to inner eye margin ( Fig. 9 ). Gena slightly narrower than eye, occipital carina complete, present along entire length of the gena. Inner eye margins strongly convergent ventrally; in frontal view about 1.4 times further apart from each other at vertex than at clypeus. Clypeus in lateral view convex at basal half, then running straight to apical margin; in frontal view about 1.1 times as wide as high ( Fig. 8 ), with basal margin almost straight and distinctly separated from antennal sockets; apical margin deeply emarginated medially, forming a sharp tooth on each lateral side ( Fig. 8 ); width of the emargination about ⅓ width of clypeus between inner eye margin. Mandible with four teeth, the first tooth quite short, the other three teeth prominent, the outer one pointed apically ( Fig. 8 ). Antennal scape about 3.5 times as long as its maximum width, curved; flagellomere I 1.8 times as long as wide, flagellomeres II–IX longer than wide, terminal flagellomere elongate, slightly curved, about 1.8 times as long as wide at its basal width ( Fig. 10 ).

Mesosoma longer than wide in dorsal view. Pronotal carina raised, strongly produced at humeral angles ( Fig. 9 ), reaching ventral corner of pronotum. Tegula with posterior lobe long and much exceeding the posterior end of the parategula (Fig. 12). Mesoscutum strongly convex, about 1.1 times as long as wide between tegulae; anterior margin broadly rounded. Scutellum weakly convex, in lateral view not at the same level of mesoscutum, with a longitudinal depression in the middle, strongly depressed along anterior margin with six to seven short longitudinal carinae. Metanotum weakly convex, slope down to apical margin. Propodeum excavated in the middle, the basal fovea about ⅓ of the length of the median carina which runs from the fovea to the apical margin ( Fig. 11 ); dorsal part of propodeum normal, without a pair of blunt teeth behind metanotum; dorsal and posterior surfaces connected by a blunt edge; border between posterior and lateral surfaces bluntly angulate.

Metasomal segment dull. Metasomal segment I narrower than segment II, truncate at base; anterior vertical surface weakly convex, with sparse punctures, clearly separable from the posterior horizontal part, with partial transverse carina at base which is visible at lateral sides. Tergum I in dorsal view about 2.3 times as wide as long; tergum II without apical lamella, about 1.3 times as wide as long (Fig. 13); sternum II in lateral view slightly convex from base to apical margin.

Body covered with short, silver hairs except lower part of propodeum with dense, long silver hairs.

Clypeus covered with strong punctures, each bearing a silver bristle, diameter of the punctures smaller than distance between the punctures. Mandible with several shallow small punctures. Frons densely covered with very coarse punctures, punctures strongly raised to form reticulation. Vertex and gena with punctures similar to those on frons. Pronotum with punctures coarser than punctures on vertex and gena, spaces between punctures very narrow, strongly raised to form reticulation. Mesoscutum densely and coarsely covered with flat-bottomed punctures, punctures on scutellum dense, coarse and equal to those on mesoscutum, punctures on metanotum smaller. Mesepisternum with punctures similar to those on pronotum posterodorsally, barely punctured anteroventrally; border between posterodorsal and anteroventral parts distinct. Dorsal metapleuron with long and strong striae, ventral metapleuron with scattered shallow punctures. Propodeum with deep coarse punctures dorsally, border between punctures cariniform; punctures deep laterally with border between punctures uncariniform; posterior surface shiny, rugose with scattered large and shallow punctures, and with longitudinal depressions along propodeal carina, widened at apical margin ( Fig. 11 ). Metasomal segments covered with strong punctures, punctures on terga I and II coarser than punctures on terga III–V, tergum and sternum IV with minute punctures.

Colour. Body black; following parts light yellow: clypeus except margin, mandible except teeth and margins, and a narrow band at apical margin of tergum I; first metasomal segment with large brown mark at lateral sides. Forewing with a dark spot at apex of marginal cell.

Etymology. The specific name fincta is derived from the Latin word ‘finctus’ (= produced), referring to the strongly produced pronotal carina at humeral angles.

Remarks. This species is most similar to Malayepipona pagdeni Giordani Soika, 1993 , in the small size, forewing with a dark spot at apex of marginal cell and metasomal tergum II without apical lamella, but can be easily distinguished from the latter by: coarser punctures on the body, pronotal carina strongly produced at humeral angles (versus pronotal carina round at humeral angles in M. pagdeni ), tegula with posterior lobe long, much exceeding the posterior end of the parategula (versus posterior lobe of tegula slightly exceeding the posterior end of parategula in M. pagdeni ), metasomal segment dull (versus metasomal segment shiny in M. pagdeni ), and tergum I in dorsal view more than twice as wide as long (versus tergum I in dorsal view less than 1.5 times as wide as long in M. pagdeni ).

Figures

Figs. 8–11. Malayepipona fincta, new species. Male (holotype): 8, Head in frontal view. 9, Head and pronotum in dorsal view. 10, Left antenna. 11, Propodeum in posterior view. 12, Tegula. 13, Metasomal segments in dorsal view. 14, Mesosoma in lateral view. 15, Habitus. Scale = 1 mm.