Pictorial key to species of the genus Ropalidia Guérin-Méneville, 1831 (Hymenoptera, Vespidae) from China, with description of one new species

Abstract Twenty two species of the paper wasp genus Ropalidia Guérin-Méneville, 1831, are listed from China. Among them, R. malaisei van der Vecht, 1962, R. cyathiformis (Fabricius, 1804), R. santoshae Das & Gupta, 1989, R. scitula (Bingham, 1897), R. obscura Gusenleitner, 1996 and R. ornaticeps (Cameron, 1900) are new records from China. A new species, R. parartifex Tan & van Achterberg, is described. Their diagnostic characteristics are summarized in an illustrated key and 36 colourplates.


Introduction
The genus Ropalidia Guérin-Méneville, 1831 (Hymenoptera: Vespidae: Polistinae: Ropalidiini), is the only polistine genus that includes both independentand swarm-founding species, so that their nests are highly variable: arboreal or in cavities, envelope present or not Nguyen 2003, Wenzel 1998). The genus can be separated from the other genera of the Ropalidiini by having the pretegular carina and dorsal episternal groove absent, the metasoma bell-shaped with its first metasomal segment petiolate and the second segment covering more or less the following segments which telescope one by one (Carpenter and Nguyen 2003). It is one of the largest polistine genera with more than 180 species and is distributed in the greater part of the Old World with a tropical or subtropical climate. The distribution is centered in the Oriental region, extending westward via Yemen to the Afrotropical region and southward to the Australian region (Kojima and Carpenter 1997, Saito and Kojima 2005a, b, Kojima 2006, Blommers 2012. The faunas of continental Africa, Australia, and New Guinea have a large number of endemic species with 18, 24 and 40 Ropalidia species, respectively. Most extreme is the fauna of Madagascar: all 43 species are endemic to Madagascar Madl 2009, Blommers 2012). Both the Indian subcontinent (26 species) and South-East Asia (about 60 species) are very speciose (Kojima 2006, Nguyen et al. 2006. Although several taxonomic studies of the genus exist, the Chinese fauna of Ropalidia is still very poorly studied (Bingham 1897, van der Vecht 1941, 1962, Cheesman 1952, Richards 1978, Das and Gupta 1989, Giordani Soika 1991, Kojima 1982, 1984, 1996a, b, 1999a, b, Kojima and Tano 1985, Kojima et al. 2002, 2005, 2007, Nguyen et al. 2006. To date, 13 valid species and subspecies of Ropalidia have been reported from China, based mainly on research and collections in areas other than continental China (Sonan 1935, van der Vecht 1941, 1962, Das and Gupta 1989, Kojima et al. 2007, 2011, Nguyen et al. 2006, Kojima 2006. Liu (1936Liu ( -1937 included 3 species of Ropalidia in his catalogue of the Vespidae of China; Lee (1982Lee ( , 1985 recorded 10 species and subspecies with an obsolete key which only distinguished species by their colour. During the following 30 years, no comprehensive and complete taxonomic studies on this large fauna have been made. During 2012-2013, the first author studied the taxonomy of Chinese Vespidae in Leiden (RMNH), Paris (MNHN) and Hangzhou (ZJUH).The result is a new illustrated key to 22 species of the genus Ropalidia from China. Six species are recorded from China for the first time and one new species is described. Distributional data are extracted from the literature as well as based on specimens examined during this study; three colour plates are added to enhance the chance of a correct identification.

.Ropalidia binghami van der Vecht, 1941
-Head wider than mesoscutum just in front of tegulae (aa); clypeus distinctly wider than high, dull and its dorsal half evenly punctate (bb); apical margin of second tergite simple ( Length between ocellus and eye (OOL) less than twice as long as length between posterior ocelli (POL) (a); first flagellomere of female antenna comparatively short, less than 2.5× as long as its apical width (b); basal angle of second submarginal cell ≥ 90°(c

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Head reddish brown and with yellow patches near its occipital carina, and temple distinctly shorter than eye in dorsal view (a); pterostigma pale brown and basal half of marginal cell subhyaline (b); first metasomal tergite strongly widened in lateral view, its length less than 1.5× its height (c); male: flagellum more or less serrate ventrally and terminal flagellomere weakly curved (d  (Cameron, 1900), rec. n.

Distribution records and taxonomic remarks
Ropalidia artifex (de Saussure, 1854), rec. n. http://species-id.net/wiki/Ropalidia_artifex Figure 1A Icaria artifex de Saussure, 1854 Remarks. Some specimens have the apical margin of the second metasomal tergite flattened, not convex as in typical specimens. In the species R. artifex, there are two subspecies e.g. R. a. artifex and R. a. fuscata van der Vecht 1941. Up to date, no distinct morphological differences between them were found, and it is hard to formally treat them as two distinct species (van der Vecht 1962, Nguyen et al. 2006. The Chinese specimens belong all to R. a. artifex.
Diagnosis. The new species is similar to R. artifex, but differs as follows: clypeus of female largely black and apically yellow (yellow with a black arrow-shaped mark in R. artifex); second metasomal tergum entirely black and strongly swollen subapically (with yellow apical band apically and weakly swollen subapically); male genitalia: proximal margin of penis gradually contracted in dorsal view and with a comparatively small hook in ventral view (abruptly contracted in dorsal view and with a large hook in ventral view).
Head. Head in frontal view about 1.2 × as wide as high; in dorsal view 2.2 × as wide as long, straightly contract behind eye, emarginate posteriorly, about 1.1 × as broad as mesonotum (including tegulae). Gena in lateral view about 0.7 × as wide as eye; occipital carina present completely, slightly sinuate laterally (Fig. 2C). Posterior ocelli slightly closer to each other than to anterior ocellus; OOL (posterior ocellusocular distance):diameter of ocellus:POL (distance between the two posterior ocelli) = 10:4:3. Inner eye margins converging ventrally, about 1.25 × further apart at vertex than at clypeus. Clypeus weakly convex, pointed apically, nearly 1.1 × wider than high. Inter-antennal distance slightly shorter than antenna-ocular distance. Antenna about 4.0 mm long, gradually thickened apically; scape slightly curved, about 4.4 × as long as its apical width; third article slightly more than 3.3 × as long as its apical width, about as long as fourth, fifth and sixth articles combined; terminal article bulletshaped, about 1.2 × as long as its basal width (Fig. 3A).
Metasoma. First segment elongate, about 3.5 × as long as high, 2.5 × as long as wide, weakly widening posteriorly from level slightly anterior to spiracle, widest at two thirds of its length and slightly contracted apically. Profile of second sternite in lateral view curved in anterior two thirds, with second tergite strongly swollen subapically (Fig. 3D, E).
Sculpture. Body covered with fine tomentum except in apical half of clypeus and with sparse setae. Clypeus, front, antero-ventral area of mesopleuron, metapleuron and sides of propodeum with scattered fine punctures; vertex, pronotum, mesoscutum, scutellum and postero-dorsal area of mesopleuron reticulate-rugose; posterior face of propodeum densely striate; first metasomal tergite shiny, with fine and sparse punctures on anterior half, and dense punctures on its posterior half; second-sixth metasomal segments dull, with dense punctures.
Colour (Fig. 2C). Body black to blackish brown with irregular reddish brown patches on the following parts: upper half of clypeus, ventral part of ocular sinus, gena, pronotum, mesopleuron antero-dorsally and propodeum laterally, but clypeus apically, mandible basally, tegula, propodeum valve and basal narrow part of second metasomal segment yellowish brown; apical half of first metasomal segment reddish brown. Coxa basally with irregular small yellow stripes. Fore wing slightly brown tinged with pterostigma yellowish brown; marginal cell and median cell apically dark brown (Fig. 3C).
Male (Figs 3F-J). Similar to female but head more transverse, in frontal view about 1.25 × as wide as high; in dorsal view 3.3× as wide as long, directly contracted behind eyes (Figs 3F,G). Antenna with 13 articles, third to terminal articles with slightly raised tyloids (Fig. 3H). Frons, clypeus, mandible, ventral antenna and antero-ventral area of mesopleuron yellow. Male genitalia (Fig. 3J): proximal margin of penis gradually contracted in dorsal view and curved slightly into a hook in ventral view.
Etymology. The species name is derived from "para" (Latin for "near") and "artifex", because it is similar to Ropalidia artifex.