Allorhynchium angulatum, Selis, 2023

Selis, Marco, 2023, Revision of the genus Allorhynchium in the Philippine Islands (Hymenoptera: Vespidae: Eumeninae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 63 (1), pp. 195-205 : 196-200

Allorhynchium angulatum sp. nov.

( Fig. 1 )

Type material. HOLOTYPE: ♀, labeled: “ PH – Mindanao / Zamboanga, Gutalac / XII.2014 // Allorhynchium angulatum / HOLOTYPUS ♀ / Det. Marco Selis ” ( MSNVE) . PARATYPES: 1 ♀, “ PH – Mindanao / Agusan, Sibagat / I.2015 ” ( MSVI); 1 ♀, “ PH – Mindanao / Cabanglasan / XII.2014 ” ( MSVI); 1J, “ PH – Mindanao / Zamboanga, Gutalac / V.2014 ” ( MSNVE); 1♀, “ PH – Mindanao, Zamboanga, / Gutalac, VIII.2014 / Leg. M.G. Felipe” ( MSVI); 2 ♀♀, “ PH – Mindanao / Zamboanga, Gutalac / XII.2014 ” ( MSVI, OLML); 2♀♀, “ PH – Mindanao / Zamboanga,Gutalac / I.2015 ” ( MSVI, OLML); 1J, “ PH – Mindanao / Zamboanga, Gutalac / III.2015 ” ( MSVI); 1♀, “ PH – Mindanao / Zamboanga,Gutalac / VI.2015 ” ( MSVI); 1 J, “ PH – Mindanao / Zamboanga, Gutalac / VII.2015 ” ( MSVI); 1♀, “ PH – Mindanao / Zamboanga, Liloy / VII.2014 ” ( MSVI).

Diagnosis. Recognized among the Philippine species by: clypeus distinctly emarginate with subtriangular and apically rounded apical teeth ( Figs 1c–d ), pronotal carina rounded on humeri, metanotum angulate and with oblique posterior face longer than horizontal anterior face, dorsal faces of propodeum distinctly below level of scutellum ( Fig. 1f ), T1 basally rounded, S2 evenly convex from base to apex, female vertex with cephalic foveae touching each other and with a small tuft of dark setae ( Fig. 1e ), male S2 shallowly convex on lateral thirds, male S7 with basal raised area about as long as flattened apical area and almost as wide as the sternite ( Fig. 1g ).

When compared with the key provided by NGUYEN et al. (2023) this species appears somewhat anomalous, showing a mix of the alternative characters: already at the first point of the key, both males and females appear intermediate having propodeal dorsum slightly below level of metanotum, weak metasomal punctures, and S7 of male with a raised basal area. The shape of male S7, however, places A. angulatum closer to the species having propodeal dorsum raised to the same level as metanotum, and the rounded pronotal carina places it in the A. argentatum -group sensu VAN DER VECHT (1963: 59). In this group, A. angulatum is readily distinguished by its deeply incised apical margin of clypeus and the propodeal dorsum placed slightly below the level of metanotum.

Another species with a similar propodeal morphology is A. concolor van der Vecht, 1963 , which is, however, readily distinguished by the shape of clypeus (with narrow incision in the middle of apical margin) and male S7 (with two elongate tubercles).

Description. Female. Body length 13.2–15.0 mm (holotype 14.6 mm); fore wing length 13.0–16.0 (holotype 14.0 mm). Habitus in Fig. 1a .

Head 1.3× as wide as long in frontal view. Clypeus 1.1× as long as wide, apical margin with rounded emargination and 0.3× as wide as clypeus width, emargination 0.25× as deep as wide, apical corners subtriangular with rounded apex and bearing short blunt carinae; clypeus in lateral view weakly convex in basal half, then shallowly depressed to apex. Distance from posterior ocellus to occipital carina 2.25× as long as distance from posterior ocellus to inner eye margin; cephalic foveae small and placed on mid-line of vertex and touching each other, separated by very narrow septum, placed in deep depression slightly smaller than one ocellus. Gena 0.75× as wide as eye at bottom of ocular sinus; occipital carina complete, strong, and shortly lamellate on gena, very fine on vertex. F1 1.7× as long as wide and 1.35× as long as F2; F2–9 more or less subquadrate, becoming progressively shorter apically; F10 bullet-shaped and shorter than F9. Sides of pronotum weakly sinuate and markedly converging anteriorly in dorsal view; pronotal carina complete and entirely rounded, slightly stronger on humeri; pretegular carina complete and strong; dorsal faces of pronotum convex posteriorly and shallowly depressed along pronotal carina. Mesoscutum 0.9× as long as wide between tegulae, evenly convex in lateral view. Scutellum distinctly convex with more or less flattened median third; anterior margin crenate; mid-line shallowly depressed in posterior third. Metanotum in lateral view oblique and weakly angulate but without distinct transverse carina, anterior horizontal face about one third as long as posterior oblique face. Tegula short and with convex surface, outer margin evenly rounded, posterior lobe subtriangular and not equaling parategula; parategula curved and with broad subtruncate apex. Mesepisternum strongly convex; epicnemial carina strong but blunt, not reaching scrobal furrow; epimeron ventrally produced. Propodeum in lateral view almost vertical, with dorsal horizontal face shorter than metanotum; dorsal face weakly convex and strongly sloping posterolaterally, touching each other behind metanotum but not forming distinct horizontal shelf, placed below level of scutellum; posterior face broadly depressed, median longitudinal carina replaced by deep subtriangular pit at dorsal margin; lateral faces mostly flattened, but curving into other faces at posterodorsal margin; dorsal and lateral carinae absent, inferior carina weak. T1 0.6× as long as wide in dorsal view, trapezoidal with rounded anterior margin; T2 wider than long and slightly wider than T1; S2 very shallowly depressed basally, evenly convex in lateral view.

Clypeus almost matte, finely shagreened and very sparsely micropunctate, with shallow oblique punctures, interspaces ranging from one to several puncture diameters. Head deeply punctured, interspaces very narrow and ridge-like on frons, flattened and reaching one puncture diameter on vertex and gena. Pronotum, mesoscutum and scutellum sculpted similarly to frons, but punctures larger and interspaces wider; mesoscutum more finely and densely punctured on sides than on disc; scutellum with impunctate area in middle of anterior margin. Metanotum very coarsely punctured, interspaces reduced to sharp ridges. Mesepisternum with large flat-bottomed punctures arranged in irregular series, deeper above scrobal sulcus, bottom of punctures shinier than interspaces; epicnemium with few shallow punctures ventrally. Metaepisternum shiny with very shallow punctures anteriorly. Dorsal faces of propodeum similar to metanotum, with very large and coarse punctures, interspaces reduced to ridges and spikes; lateral faces with very shallow flat-bottomed punctures arranged in longitudinal series, interspaces reduced to irregular striation; posterior face with strong oblique striae originating from median carina, some shallow punctures along dorsal margin. Metasoma silky shiny with extremely fine micropunctures; tergites with sparse punctures, interspaces reaching up to several puncture diameters, finer and shallower on disc, becoming stronger and deeper on sides; punctures becoming progressively finer from T3; S1 shiny with irregular sculpture; S2 strongly shiny with deep punctures, coarser on sides than on basal depression, becoming denser posterolaterally; S3–6 similar to respective tergites. Head and mesosoma with short pale pubescence; frons and dorsal side of mesosoma with apically bent setae; clypeus with short oblique setae outstanding from very short pubescence; mesepisternum with denser and whitish pubescence and longer setae; metasoma with dense dust-like grayish pubescence and scattered oblique setae.

Entirely grayish-black, with very short pale yellow line between eye and antennal insertion. Wings strongly fuscous with blue to purple reflections.

Male. Body length 11.5–14.0 mm; fore wing length 12.0–15.0 mm. Habitus in Fig. 1b .

Similar to female, differing as follows: apical margin of clypeus more deeply emarginate, emargination 0.30–0.35× as deep as wide, F3–9 slightly convex dorsally, F11 claw- -shaped and apically pointed, not reaching basal margin of F9, S2 slightly more depressed medially, S7 with large semicircular raised area basally, as long as or longer than flattened apical area and basally as wide as sternite itself. Genitalia in Fig. 1h .

Etymology. The specific name is the Latin adjective angulatus (- a, - um), meaning angulate, given in reference to the angulate apical corners of the clypeus.

Distribution. Philippine Islands: Mindanao ( Fig. 6 ).

Figures

Fig. 1. Allorhynchium angulatum sp. nov. a – habitus of female; b – habitus of male; c – head of female in frontal view; d – head of male in frontal view; e – head of female in dorsal view; f – mesosoma in posterodorsal view; g – metasoma of male in ventral view; h – male genitalia (aedeagus in ventral and lateral view, digitus).

Fig. 6. Distributional map of Philippine species of Allorhynchium van der Vecht, 1963.