A new species of the social wasp genus Chartergellus Bequaert from Trinidad

A new species of the social wasp genus Chartergellus is described, Chartergellus trinitatis Carpenter and Andena, NEW SPECIES. Male genitalia are described and comparative remarks are given.


Introduction
Chartergellus has been described as one of the least abundant genera of neotropical social wasps (Jeanne, 1991), being rarely collected and seldom found in collections.The colonies are small, with few individuals, except C. communis suspended from substrate one below the other, not in contact with envelope, which is a single sheet (Wenzel, 1998).According to Richards (1978) the nest of C. atectus Richards, 1978, is constructed between leaves and lacks a full envelope.Bequaert (1938) described Chartergellus as a subgenus of Chartergus sensu Bequaert [=Parachartergus von Ihering], designating Vespa frontalis Fabricius, 1804, as its sole species.Richards (1978) raised it to genus, described five new species and designated C. amazonicus Richards, 1978, as a replacement name for Vespa frontalis Fabricius, which was preoccupied by Vespa frontalis Latreille, 1802.He remarked that it is uncertain whether this species is identical with C. frontalis sensu Bequaert, but as discussed by Carpenter and van der Vecht (1991), there are no grounds for considering Bequaert to have misidentified this species.Later, four more species were described: C. afoveatus Cooper (Cooper, 1993) (Grandinete et al., 2015) and Mateus and Andena (Mateus et al., 2015).West-Eberhard et al. (2010) also established that C. zonatus (Spinola, 1851), treated as unrecognized by Richards (1978), is a good species.Thus, there are 11 species recognized up to the present The new species, here described and named Chartergellus trinitatis, was collected by C. K. Starr in Trinidad.It is the species referred to as Chartergellus nr.atectus in Starr and Hook (2003).Female: Size: 10.0 -10.3 mm Fore wing: 10.1-10.3mm in length; infuscate, venation blackish, pterostigma as long as wide, tip truncate.Color: Blackish species; yellow marks on: lower part of clypeus, extending to middle region -"U-shape"; spots on inner part of eyes and two spots on inter-antennal area; a large stripe from top to bottom of gena, extending to malar space area; mandible with a strip on top region; dorsal region of pronotum, margin of the scutum; a spot on ventral corner of pronotum, extending to fovea; mesopleuron with a dorsal spot; tegula with a spot posteriorly; scutellum and metanotum with a band on anterior region; propodeal concavity with two bands extending from top to bottom; tergum I and II with yellow bands; sternum II-V also with yellow bands, evanescent; yellow band extending from top to bottom on tibia and a spot on last tarsomere of anterior leg; antenna blackish, bottom of the last three antennomeres reddish.Variation: workers may have yellow stripes, on tergum I and II, opaque or vanishing (see arrows in Figs 1 and 2).Castes: The castes in this species are readily distinguishable by slight but reliable color characters.The queen have their yellow marks with a brownish tinge, while those of the workers are more clearly yellow.width of each cell in other combs is 4.5 mm.Surrounding the set of combs is a relatively smooth envelope of light-gray carton with a single entrance hole of about one centimeter diameter below.The envelope is free of all except the first comb.It comprises several layers, touching each other in many places, with a separation of about one millimeter between adjacent layers.The number of layers is greatest above, reducing to one toward the bottom.

Comparative Remarks
The new species resembles Chartergellus afoveatus, in color and general aspects, however the punctures are much smaller and less evident (see Fig 3 A,B,C and D,and Fig 4 A,B,C and D).Also it has a fovea, which is deep; the ventral corner is prominent (bulging) and the dorsal pronotal carina is less raised, sharp and extending to middle of pronotum (Fig 4 C and D).The mandible is slightly produced as in C. afoveatus.The rim of the mandible is a variable feature, ranging from very feeble, as in C. sanctus, to strongly produced, as in C. communis.In C. trinitatis the rim is absent as in C. atectus, C. jeannei, C. nigerrimus Richards, 1978, and C.  The pendant nest is quite different from all other nests known in the genus.Externally, it resembles a Pseudopolybia nest with an envelope composed of multiple sheets, rather than a single sheet, as in other Chartergellus.Internally the combs are supported from one another by petioles, rather than connected to the substrate directly, as in other Chartergellus.
Chartergellus trinitatis Carpenter & Andena (Figs 1-2, 3A, C, E, 4A, C, 5-7) Diagnosis: This is one of the largest species of Chartergellus, ranging from 10.0 -10.3mm in length, a little bigger than C. sanctus Richards, 1978.The species is easily diagnosed by the dorsal pronotal carina little raised and sharp, extending to middle of pronotum; the pronotal fovea deep and oval, ventral corner bulging, very produced (see Fig 4 C and D); the punctures on the scutum very small and spaced (Fig 4 A).

Fig 4 .
Fig 4. A and C: scutum in dorsal view and pronotum in lateral view of Chartergellus trinitatis, respectively; B and D: scutum in dorsal view and pronotum in lateral view of Chartergellus afoveatus, respectively.Scale bar = 1.0 mm.
zucchii.Chartergellus atectus, C. amazonicus, C. golfitensis, C. afoveatus, C. punctatior Richards, 1978, and C. trinitatis have the clypeus touching the eyes, although, as pointed out by Mateus et al. (2015), C. punctatior may have the clypeus narrowly separated from the eyes.Only C. zucchii, C. sanctus and C. punctatior have the clypeus convex, and, as in the remaining species of the group, C. trinitatis has the clypeus compressed.The pubescence covering the top half, or more, of the clypeus is another feature of C. trinitatis shared with C. afoveatus, C. communis, C. nigerrimus, C. punctatior, C. sanctus, C. zonatus, and C. zucchii.Chartergellus afoveatus and C. trinitatis have the pubescence covering the entire clypeus, with only the tip bare (Fig 3 A and B).The scutum is less punctured than in C. afoveatus, and the anterior margin of pronotum (dorsal view) is more "square" (Fig 4A and B); the humeri are not produced.The propodeal valvula is widened anteriorly, as in C. nigerrimus and C. amazonicus.Also, despite the yellow bands on the metasomal tergum being very similar to C. afoveatus, they are narrower.