Pampathynnus Carnimeo, 2018

Carnimeo, Fernando Henrique & Noll, Fernando Barbosa, 2018, On the dumping ground genus Scotaena Klug, 1810 (Hymenoptera: Tiphiidae: Thynninae): Phylogeny, taxonomy and geographic distribution, Zootaxa 4399 (4), pp. 451-490 : 475-476

Pampathynnus Carnimeo , gen. nov.

Type species: Scotaena pubescens ( Klug, 1840)

Male description. Head: Antennal sockets under supra-antennal projections, with feebly developed rounded margined supra-antennal plate on the medial apex. The apex of the supra-antennal plate separated to each other by a distance bigger than the width of one plate. The middle of the plate with a tubercle (in P. pubescens ) or raised on a slight longitudinal line centrally (in P. vigilii ); clypeus apical margin with medium central notch, with depth from about 1/3 to 1/4 of clypeus length. The teeth formed laterally to the notch is thin and acute towards down. Basal region of the clypeus convex and depressed on the basolateral margins. Basolateral margins diagonals. Laterals of the apical margins concave; Mandible bidentate, the apical tooth long and acute, the subapical short and rounded. Basal region of the mandible triangular shaped, slightly flattened; maxillary palpi with palpomeres about the same size, the III rd often shorter and broader; antennae filiform, with 11 flagelomeres, the apical ones slightly arcuate. Abundant pale silver pubescence on the whole body, thinner in P. vigilii .

Mesosoma: Pronotum slightly constricted in the middle, forming a small elevation anteriorly and a larger one posteriorly, in lateral view. Anterior margin carinated and narrower than the posterior; forewing with nervure 2mcu received by beyond about 1/4 of the base of the submarginal cell; forewings hyaline, ferruginous on the anterior margins and stigma. The marginal cell darker than the rest of the wing; mesoscutum subquadrate in dorsal view, with dorsal surface slightly convex. A pair of longitudinal submedial sutures and a pair of longitudinal carina laterally, culminating in a transverse posterior carina; scutellum dorsally convex with rounded surface. Delimited anteriorly by a deep transverse suture and the posterior margin rounded. Latero-posterior margins with borders enlarged towards the axilla; metanotum short with two sublateral fossae; mesopleural transverse sulcus strongly marked; metapleuron triangular in lateral view; propodeum concavity obliquus posteriorly, widely rounded laterally. Often with transverse striae dorsally. Apex of the propodeum with two petiolar grooves laterally to the petiolar socket; a pair of longitudinal sutures on the ventral surface of the mesepistenum; forecoxae with ventral surface flattened, with the inner margin straight and the outer broader and rounded in P. vigilii or diagonal, subtriangular in P. pubescens ; slightly depressed longitudinally on the ventral surface. Hindcoxae with longitudinal carina on the dorsal surface; posterior margins of the mid and hindtibiae with row of projections or serrations, more conspicuous on hindtibiae. With short carina on the external base of the tibia; hindfemoral-hindtibial joint lobes asymmetrical with inner lobe slightly longest and thickened posteriorly;

Metasoma: Metasoma with constrictions between the segments, mainly in lateral view; first metasomal tergite with length approximately as long as its apical breadth. With a longitudinal sulcus reaching more than half the segment extension. Spiracles slightly raised; apical margins of tergites I–VI with transverse smooth fasciae, preceded by a transverse row of setae horizontally arranged; sternite I with subapical surface slightly raised in two lateral lobes, slightly depressed longitudinally between the lobes in P. vigilii ; epipygium oval, constricted before the apical margin, with flared apical border. Strongly and deeply punctuated; hypopygium subquadrate with rounded margin.

Coloration. Body predominantly black, with a few yellow markings, mostly on the metasoma.

Etymology. From the Quechuan, the family language of the South American indigenous people Quechua, pampa means “plain” and was adopted to refer to the South American lowlands. The name fits with facets of this wasp’s structure and distribution the synapomorphy supporting the genus is the flattened ventral surface of the forecoxae and the included species occur in the Pampean region. The suffix thynnus is commonly used in the Thynninae genera.

Included species: Pampathynnus pubescens and P. vigilii .

Distribution. South of Brazil: Rio Grande, Rio Grande do Sul and Araranguá, Santa Catarina, Brazil. Montevideo, Uruguay. Alta Gracia, Cordoba, Argentina.

Discussion. The two included species can be easily distinguished by a set of features present in P. pubescens and absent in P. vigilii : strong transverse striae on the dorsal surface of the propodeum, raised inner margin of the forecoxae and abundance of thick body pubescence.