Descriptions of three new species of the genus Stenodyneriellus Giordani Soika with keys to some related species (Hymenoptera, Vespidae, Eumeninae)

Abstract Three new species, namely Stenodyneriellusangustussp. n. from Thailand, S.profundussp. n. from Philippines, and S.longitergussp. n. from Indonesia, are described and illustrated in detail. Stenodyneriellusmaculatus Gusenleitner, 2013 is newly recorded from Vietnam. Two keys to some related species are also provided.


Introduction
To date, there are 64 species and five subspecies recorded in the genus Stenodyneriellus Giordani Soika, 1962 from the Oriental and Australian regions (Giordani Soika 1994, 1995, 1996Borsato 1993Borsato -1994Borsato , 2003Gusenleitner 1996Gusenleitner , 2007Gusenleitner , 2008Gusenleitner , 2013Li and Chen 2016;Selis 2016;Girish Kumar et al. 2017). Based on the foregoing publications, three species found in the collections of the American Museum of Natural History are confirmed as new to science. Furthermore, S. maculatus Gusenleitner, 2013 is a new record from Vietnam. In the present paper, these new species are described and illustrated in detail. Given that the existing keys to the species of Stenodyneriellus are nearly comprehensive, two keys to some related species are provided in this paper.

Materials and methods
The specimens examined are deposited in American Museum of Natural History, New York (USA; AMNH), and Queen Sirikit Botanic Garden, Chiang Mai (Thailand; QSGB). Descriptions and measurements were made under a stereomicroscope (Nikon SMZ1500), and all figures were taken with Microptics-USA/Visionary Digital photomicrograph system developed by Roy Larimer and multiple layers stacked using Helicon Focus. The ratios used throughout the descriptions were measured in the same magnification of the stereomicroscope. All measurements were taken as the maximal length of body parts measured. Body length was measured from the anterior margin of the head to the posterior margin of metasomal tergum II. For the density description of punctures, "sparsely" means that interspaces are larger than puncture diameters, "moderately" means equal to the diameter, and "densely" means less than the diameter. The abbreviations used for morphological terms in the text are shown as follows: A, T, and S refer to numbered antennal articles, metasomal terga and metasomal sterna, respectively; and OOD and POD mean ocellocular distance and post ocellar distance, respectively. Morphological characters and terminology principally follow Giordani Soika (1994) and Li and Chen (2016 Description. Female ( Fig. 1): body length 6.5 mm, forewing length 6.0 mm. Black, with the following parts yellow: basal arched band and apical band on clypeus (Fig. 2), two spots on outer and inner sides of mandible basally, scape ventrally, ocular sinus, interantennal spot, a longitudinal spot on frons, a long band on gena, anterior median band on dorsal surface of pronotum, a small dorsal spot on mesepisternum, small spots of tegula anteriorly and posteriorly, parategula, a narrow transverse band on basal margin of scutellum, an irregular submedian spot and a tiny apical spot on dorsal surface of propodeum (Fig. 3), an apical band on each of T1-T5 (Fig. 4), an interrupted apical band on S2, lateral spots on S3-S4, apexes of fore and mid femora ventrally, and all tibiae ventrally; brown to dark brown: apical margin of clypeus, mandible except yellow spots, terminal segments of antenna ventrally, legs except yellow parts, and most of tegula. Wings lightly infuscate. Setae pale brown.
Mesosoma. Pronotal carina complete, rounded dorsally and emarginated laterally; anterior surface of pronotum smooth; dorsal surface of pronotum, mesoscutum, mesepisternum, mesoscutellum, metanotum, and both dorsal and lateral surfaces of propodeum coarsely and densely punctate, punctures on mesepisternum, metanotum, and both dorsal and lateral surfaces of propodeum relatively denser and shallower, their interspaces distinctly carinate, reticulate, and similar to those of frons; mesoscutum evenly convex; mesoscutellum flat; metanotum slightly sloping; dorsal surface of propodeum almost in the same horizontal plane as metanotum, without distinct teeth behind metanotum, without superior carina; posterior surface widely and deeply depressed, forming a central cavity (Fig. 3), and well-separated from dorsal surface, smooth, and with a median longitudinal carina. Tegula wide, length slightly longer than its width, and posterior lobe short and small, almost in the level of apex of parategula.
Metasoma. In dorsal view, T1 domed, its width 1.91× length and 0.82× width of T2, basally without a transverse carina, anterior surface coriaceous, impunctate, and almost vertical, dorsal surface with very sparse punctures; T2 apically with a narrow, translucent and blade-shaped lamella (Fig. 4), punctures on T2 and other terga similar to those of T1; S2 widely depressed basally, punctures of S2 and other sterna a little bigger and denser than those of terga; apical yellow bands of T1-T2 wider than those of other terga and with U-shaped gaps mesally.
Remarks. This species is similar to S. sublamellatus Giordani Soika, 1994, from Malaysia by the character of T2 with a narrow, translucent, blade-shaped lamella apically (Fig. 4). It differs from the related species and all other members of the genus by the following character combination: posterior surface of propodeum ( Fig. 3) with a wide and deep central cavity and well-separated from dorsal surface, A5 wider than long, and lateral side of pronotum normal, not concave.
Distribution. Thailand. Etymology. The specific name is the Latin adjective angustus (= narrow), which refers to T2 with a narrow, translucent and blade-shaped lamella apically. Description. Male (Fig. 5): body length 9.0 mm, forewing length 9.5 mm. Black, with the following parts yellow: clypeus (Fig. 6), basal spot on outer side and long band on inner side of mandible, a band along inner eye orbit from base of clypeus to vertex occupying entire ocular sinus, ventral scape, big interantennal longitudinal band connecting clypeus, gena, anterior band on dorsal surface of pronotum, two submedian vertical lines on mesoscutum, a large dorsal spot and a large longitudinal ventral band on mesepisternum, round band of tegula, parategula, basal halves of both scutellum and metanotum, apical part of propodeum, an apical band on each of T1-T6 and S3-S6, S1 and most of S2 except for median triangle dark brown spot, two basal spots on lateral side of T1 (a large spot and a small one), one large basal spot on lateral side of T2, small median spots on both T7 and S7, ventral sides of all coxae and tibiae, and some or then most of all femora, tibiae, all first tarsi; reddish brown to brown: mandible except for yellow parts, antenna ventrally except for scape, both lateral and posterior surfaces of propodeum, T1 and T5-T7 except all yellow parts, triangle spot of S2, tegula except yellow part, and all legs except yellow parts. Wings lightly infuscate. Setae pale brown.

Stenodyneriellus profundus
Head. Clypeus (Fig. 6) moderately punctate, wholly very convex, approximately as wide as (1.03×) long, total width 2.67× apical width, apex broadly and deeply emarginated into an arc of a circle, forming two long and sharp apical teeth which delimit a wide and entirely concave median area apically, apical width 1.5× emargination depth and as wide as interantennal space; interantennal carina prominent; frons evenly convex, and coarsely and densely punctate; vertex and gena moderately punctate; POD much shorter than (0.6×) OOD; A13 small, conical and pointed and backward just beyond the middle of A11.
Mesosoma. Pronotal carina complete, rounded dorsally and emarginated laterally; anterior surface of pronotum wholly coriaceous and impunctate; dorsal surface of pronotum moderately punctate medially and densely punctate laterally and apically; mesoscutum, mesepisternum, mesoscutellum, metanotum sparsely to moderately punctate, similar to those of vertex and gena, punctures of mesoscutellum slightly sparser than those of other above parts; mesoscutum slightly convex; both mesoscutellum and metanotum flat; dorsal surface of propodeum punctate, punctures shallow, flat bottomed and interspaces slightly carinate, in the same horizontal plane as metanotum, with two small and translucent teeth behind metanotum, without superior carina; posterior surface smooth, with medial longitudinal carina, widely and deeply depressed forming a central cavity (Fig. 9), well-separated from dorsal surface; lateral surface of propodeum coriaceous and very sparsely punctuate. Tegula length slightly longer than its width, and posterior lobe small, almost reaching apex of parategula.
Metasoma. In dorsal view, T1 domed, its width 1.78× length and 0.80× width of T2, basally without a transverse carina, anterior surface vertical, smooth, and separated from dorsal surface, dorsal surface coriaceous and with very sparse, tiny punctures; T2 without a translucent and blade-shaped lamella apically, punctures on T2 and other terga similar to those of T1; S2 widely depressed basally, punctures of sterna similar to those of terga; apical yellow bands on T1-T4 wider medially, with small gaps medially, apical band of T6 interrupted laterally, and all apical yellow bands of sterna with U-shaped gaps medially. Giordani Soika, 1994, from the Head. Clypeus (Fig. 13) densely punctate and evenly convex, approximately as wide as long, total width 2.25× apical width, apex wider than (1.33×) interantennal space, almost truncated and just slightly emarginated mesally; interantennal carina prominent; A5 wider than long; frons evenly convex, and coarsely and densely punctate, interspaces carinate and reticulate; punctures on vertex and gena slightly sparser than those of frons; POD much shorter than (0.6×) OOD.

Remarks. This species is similar to S. flaviventris
Mesosoma. Pronotal carina complete, waved dorsally and slightly emarginated laterally; anterior surface of pronotum smooth; dorsal surface of pronotum densely punctate, interspaces between punctures carinate, punctures on mesoscutum, mesoscutellum, mesepisternum and metanotum similar to or slightly sparser than those of pronotum; mesoscutum convex; mesoscutellum flat; metanotum slightly sloping apically; dorsal surface of propodeum thickly punctate, punctures shallow, flat bottomed and interspaces distinctly carinate and reticulate, in the same horizontal plane as metanotum, without teeth behind metanotum, with superior carina; posterior surface widely and deeply depressed forming a central cavity (Fig. 14), clearly separated from dorsal surface, both posterior and lateral surfaces coarsely punctate and with thin and transverse striae; tegula longer than wide, and posterior lobe small and somewhat shorter than parategula.
Metasoma. In dorsal view, T1 (Fig. 15) elongate, approximately as long as wide apically, much narrower than (0.68×) T2, basally without a transverse carina, anterior surface not well-separated from dorsal surface, dorsal surface of T1 except for apical band densely punctate, interspaces between punctures slightly less than diameters and distinctly sparser than those of propodeum; T2 without a translucent and bladeshaped lamella apically, punctures on T2 and other terga smaller and sparser than those of T1; S2 widely depressed basally and sparsely punctate; apical bands of T1-T2 wider than those of other terga, and those of T2-T5 with small gaps medially.
Remarks. This species is similar to three Philippine species (S. nitidus Giordani Soika, S. plurinotatus Giordani Soika, and S. rufinodus Giordani Soika) in sharing the elongate character of T1: it is approximately as long as wide at the apex, and much narrower than T2. It differs from these three related species as shown in the following key.
Distribution. Indonesia. Etymology. The specific name longitergus is derived from two Latin words, long and tergus, which refers to T1 being elongate, approximately as long as wide apically. Posterior surface of propodeum with large central depression and clearly separated from dorsal one (Fig. 14); punctures of T1 much sparser than those of dorsal surface of propodeum; clypeal apex wider than ( Diagnosis. Clypeus in female basally with a yellow transverse band and apically with two yellow spots, in male wholly yellow; anterior surface of T1 and legs without red marks; clypeus slightly wider than long, apex truncated and narrower than interantennal space; frons, vertex and gena coarsely, deeply and densely punctate; A13 of male hooked, narrow, conical and just reaching backward the base of A12; posterior surface of propodeum smooth, widely and deeply depressed forming a central cavity, well-separated from dorsal surface; T2 without a translucent and blade-shaped lamella apically, T2-T5 clearly punctured. Distribution. Vietnam (new record); Thailand.