New genus and species of Pompilinae spider wasps from the Oriental Region (Hymenoptera, Pompilidae)

The new genus Erythropompilus Shimizu & Pitts, gen. nov. from the Oriental Region (Pompilidae, Pompilinae) is described, based on the new species E. malaysiensis Pitts & Shimizu, sp. nov. from Malaysia. Two other new species of this genus, E. thailandensis Pitts & Shimizu, sp. nov. from Thailand and E.  taiwanensis Pitts & Shimizu, sp. nov. from Taiwan, are also described. A key to the species is provided, and the taxonomic position of the genus is discussed.


Introduction
In the course of studying the systematics of spider wasps (Hymenoptera: Pompilidae) globally and more specifically from the Oriental and Australasian regions, we recently examined specimens from Malaysia, Thailand, and Taiwan belonging to the subfamily Pompilinae. From these regions, we found species, specimens of which were collected in Malaise traps and yellow-pan traps, of an enigmatic and unknown genus. A comparison of this genus with other genera in the Old World was performed, and we concluded that the specimens belong to an undescribed genus. Through detailed examination of the specimens, we also concluded that those specimens from the three regions belong to three separate undescribed species.
In this paper, we create a new genus, Erythropompilus Shimizu & Pitts, gen. nov., based on the new species E. malaysiensis Pitts & Shimizu, sp. nov. from Malaysia (type species). We also describe two other new species of the genus, E. thailandensis Pitts & Shimizu, sp. nov. from Thailand and E. taiwanensis Pitts & Shimizu, sp. nov. from Taiwan, we provide a key to the species, and we discuss the taxonomic position of the genus at the subfamily level.

Materials and methods
Holotypes were photographed with a digital camera (Nikon Coolpix 4500 and MDC lens equipped with a stereo microscope Leitz TS and a transmitted light microscope Leitz Dialux). Photographs were stacked by using CombineZM (Hadley 2008), and the final synthesized photographs were post-processed for contrast and brightness using Adobe Photoshop software.
Of these features, the very sharply grooved outer orbit in both sexes, placoid sensilla on the flagellomeres, a pair of large, medially directed lateral hooks on S6, the very short, peg-like paramere, and the very broad and sinuate parapenial lobe in the male are unique to this genus. Our preliminary phylogenomics strongly support the close relationship of the genus with Tachypompilus Ashmead, 1902 and Ctenagenia Saussure, 1892.
Description. Female. Greater part of body and legs with silvery-white pubescence densely. Vertex along inner orbit, labrum, and fore coxa posterobasally with sparse fine setae; S2-S6 with short erect setae, those on S6 dense.
Fore tibia with several short spines internally. Fore tibial spur pale yellow. Fore tarsus lacking tarsal comb, without spines interiorly and exteriorly (Fig. 1G). Dorsal faces of mid and hind tibiae with several spines in exterior and interior rows (Figs 3H, 5I). Hind tibia with apical spines of unequal length and thickness, more or less splayed out and irregularly spaced, lacking integumental serrations dorsally. Orbicular pecten comprising about seven long divergent fine setae (Fig. 1G). Tarsal claws with inner ray much broader than outer ray, obliquely truncate (Fig. 3E). Longest seta of orbicular pecten much longer than orbicula itself (Fig. 1G).
FW inner fascia broad on both sides of second abscissae of veins Rs and M (basal vein) and crossvein cu-a (Figs 1H, 3F, 5E); outer fascia occupying basal half of marginal, SMCs 2 and 3, apical half of discal cell 2, and basal fourth to third of discal cell 3; outer wing margin infuscate; area between outer fascia and outer infuscate margin somewhat whitish. Pterostigma long, its base being much longer than crossvein 2r-rs. SMC2 shorter than SMC3 on vein M, longer than SMC3 on vein Rs. Crossvein 2rs-m nearly straight, oblique to vein M. Crossveins 3rs-m and 2m-cu curved outward. Vein Cu-A 1 slightly deflected posteriorly at its base. Crossvein cu-a at or slightly distal to separation of vein M+CuA. A cluster of basal hamuli strongly proximal to separation of vein C from vein Sc+R+Rs. HW crossvein cu-a originating much basal to fork of vein M+CuA, forming angle with vein A, short and gently curved (Figs 1H, 3F, 5E). Jugal lobe small and elliptic, about third of subbasal cell in length. S2 without transverse groove or depression. S6 not compressed laterally without median carina.
Distribution. The Oriental Region (Thailand, Malaysia and Taiwan). Etymology. The generic name is derived from the type species, of which the female mesosoma is orange-red for most part. The name is considered masculine.  ; and mid and hind femora with small spines set in pits apicodorsally. Female: thorax mostly orange-red (Fig. 1K); gena, in dorsal view, very thin, abruptly receding posteriorly (Fig. 1B); and lateral margin of pronotal dorsum, in dorsal view, slightly narrowing anteriorly (Fig. 1B). Male: frons, in profile, gently convex (Fig. 2I); placoids small, shorter than half of each flagellomere (Fig. 2E); thorax usually dark rufous (Fig. 2I); SGP arrowhead-shaped with rounded apex (Fig. 2F); and inner margin of parapenial lobe smooth (Fig. 2G, H).

Key to the species of Erythropompilus
Description. Holotype female. Length: Body 6.5 mm; forewing 5.7 mm. Head  0.57. SMC3 narrowed on vein Rs by 0.29 × its length on vein M, receiving crossvein 2m-cu at basal 0.45, removed from outer wing margin by 1.5 × its own length.
Mid tibia with five to eight spines externally and two or three spines internally. Hind tibia with six to eight spines externally and five to seven spines internally. Longer spur of hind tibia 0.63-0.71 (0.69) × hind tarsomere 1.
Pronotum, in dorsal view, distinctly narrowing anteriorly (Fig. 2B). Mid tibia with five or six spines externally and two or three short spines internally. Hind tibia with five to eight spines externally and four or five spines internally. Longer spur of hind tibia 0.65-0.83 × hind tarsomere 1.
Mid tibia with four spines externally and one spine internally; hind tibia with five or six spines externally and five spines internally (Fig. 3H). Longer spur of hind tibia 0.63 × hind tarsomere 1.
FW and HW as shown in Fig. 3F. Marginal cell removed from wing tip by 0.46 × its own length. SMC2:SMC3 = 1:1.3 on vein M, 1:0.48 on vein Rs. SMC2 narrowed on vein Rs by 0.82 × its length on vein M, receiving crossvein 1m-cu at basal 0.5. SMC3 narrowed on vein Rs by 0.3 × its length on vein M, receiving crossvein 2m-cu at basal 0.54, removed from outer wing margin by 1.8 × its own length. Crossvein cu-a originating slightly distal to point of separation of vein M+CuA, leaning toward wing base. HW jugal lobe less than third of subbasal cell in length.
Male. Based on the only paratype. Body 3.8 mm; forewing 3.6 mm. Body and legs reddish brown (Fig. 4C); scape and pedicel yellowish brown beneath.
Metapostnotum very short, 0.06 × as long as metanotum at midline. FW and HW as shown in Fig. 4D. Marginal cell removed from wing tip by 0.38 × its own length. SMC2:SMC3 = 1:2 on vein M, 1:0.67 on vein Rs. SMC2 not narrowed above, receiving crossvein 1m-cu at basal 0.43. SMC3 narrowed on vein Rs by 0.34 × its length on vein M, receiving crossvein 2m-cu at basal 0.51, removed from outer wing margin by 1.5 × its own length. Crossvein cu-a perpendicular to vein A.
Mid tibia with very small spines dorsally, three spines externally and two spines internally. Hind tibia with spines longer than those on mid tibia, five or six spines externally and three or four spines internally. Longer spur of hind tibia 0.65 × hind tarsomere 1.
SGP somewhat concave beneath. Genitalia (Fig. 4G, H): volsella slender but broadened apically with rounded apex and several long setae; parapenial lobe extending far beyond apex of volsella; aedoeagus parallel-sided for most part.

Discussion
In recent molecular phylogenetic analyses, the monophyly of the subfamily Pompilinae was well supported, more so than the other large subfamily Pepsinae (Waichert et al. 2015;Rodriguez et al. 2016). With traditional morphological studies, the family Pompilidae, as well as this subfamily, is well defined, although the morphological The prementum has a preapical circular, or heart-or spade-shaped membranous area (Shimizu 1994).
This feature is applicable to almost all members of Pompilinae, although the verification of the condition is difficult. To examine the degree of the sclerotization of the apical prementum, in many cases, the labio-maxillary complex has to be removed from a specimen after softening the specimen with water vapor.
Erythropompilus possesses all the above features, and, thus, this genus should be treated as a member of Pompilinae. We are currently conducting molecular phylogenetic analyses using ultra-conserved elements, and the preliminary phylogenomics highly support this subfamilial position of the genus and its close relationship with Tachypompilus and Ctenagenia.