No abstract

Scotaena is considered a dumping ground genus of the Neotropical thynnine, having both a complicated taxonomy and a poorly known geographical distribution. This work presents the first records of Scotaena decora (Smith, 1859), and Scotaena polistoides Turner, 1910 in 13 areas of the Brazilian Atlantic Rainforest in São Paulo state, Brazil. Both species were previously known only from their type localities, in Amazonia, Brazil and Chaco, Paraguay, respectively. These new records expand the range of distributions of both species to a new biome and contribute to the natural history of the genus.

The Neotropical thynnine genus Scotaena is revised and a cladistic analysis is presented. The analysis, conducted from 75 morphological characters of 31 terminal taxa, returned a single tree under equal weighting. The monophyly of Scotaena was not recovered. Three new genera and five new species are described: Kaysara gen. nov., Pseudoscotaena gen. nov. and Pampathynnus gen. nov., Scotaena reversa sp. nov., Kaysara laterolata sp. nov., Kaysara apiciconcava sp. nov., Kaysara marginoplicata sp. nov. and Kaysara levicrenata sp. nov. Three species are transferred to other genera as follows: Eucyrtothynnus rosenbergi (Turner, 1910) comb. nov., Glottynoides genisei Kimsey, 1991 comb. nov., Ornepetes clypearis Durán-Moya, 1941 comb. nov. Scotaena now comprises four species: S. trifasciata Klug, 1810; S. horni (Turner, 1927); S. vetusta Turner, 1909; and S. reversa. An identification key and geographical distribution maps for the studied species are also provided.

The Dufour gland of two Myzinum females was studied with light and electron microscopy, and is formed by a large sac lined with a monolayered secretory epithelium. The epithelium displays a crenellate appearance, which is the result of the peculiar shape of the secretory cells, that have a cupola-like central portion and a more flattened appearance in the contact region with other cells. The ultrastructural organization is indicative for the elaboration of a non-proteinaceous secretion. The gland opens ventrally to the sting base, but does not open through the sting, as does the venom gland duct. The sting itself is dorsally curved, which may be a functional adaptation to facilitate stinging large beetle larvae from above, as these are the common hosts for tiphiid wasps.

No abstract