Stenosigma humerale Giordani Soika, 1990

Hermes, Marcel G. & Ferreira, Wellington D., 2016, On the type series of Stenosigma humerale Giordani Soika with the description of a new species (Hymenoptera, Vespidae, Eumeninae), Revista Brasileira de Entomologia 60 (2), pp. 123-127 : 123-124

Stenosigma humerale Giordani Soika, 1990 ( Figs. 1–9 )

Stenosigma humerale Giordani Soika, 1990: 148 (key), 155. Type data: holotype female (MSNVE). Type locality: Mapiri , Bolivia.

Stenosigma humerale resembles some wasps of the genus Pachymenes (e.g., P. ater de Saussure, 1852 and P. ghilianii (Spinola, 1851)) in both shape/size and color. It is likely that this species is part of a mimetic ring that includes other genera such as Montezumia de Saussure, 1852 (e.g., M. cortesia de Saussure, 1852 and M. cortesioides Willink, 1982 ) and Agelaia Lepeletier, 1836 (e.g., A. angulata (Fabricius, 1804)) , besides Pachymenes , which may present a great deal of variation in the distribution of yellow markings upon a brownish background body coloration. These mimetic rings are common among eumenines and polistines, and other examples may be found in Hermes (2010) and Garcete-Barrett (2014).

The type material of S. humerale housed at the Museo Civico di Storia Naturale di Venezia and at the Natural History Museum of London was studied. It was previously composed by the holotype female and the allotype male, both from Bolivia, two male paratypes also from Bolivia, two female paratypes from Peru and one male paratype from Colombia. One of the female paratypes from Peru was identified by Bequaert ( Fig. 10 ) as Pachymenes velutina Ducke, 1911 . Later, this specimen was examined by van der Vecht, who attached a label to it ( Fig. 11 ) and contradicted Bequaert’s conclusion, considering P. velutina similar to P. ghilianii . Finally, when revising a series of Neotropical genera, Giordani Soika (1990) placed this specimen within Stenosigma and attributed it to a new species, including it in its type series ( Fig. 12 ). Clearly, the specimen is not a Pachymenes for it bears the lateral pronotal carina and a pre-apical fossa on T1 (both features are absent in Pachymenes ).

This female specimen ( MSNVE), as well as one additional female and one male paratypes ( NHM), however, show consistent structural differences when compared to the holotype and allotype, which is evidence to treat them as a separate species. The mentioned male from Colombia at the NHM is labeled as a paratype, but it is not mentioned in Giordani Soika’s (1990) paper. According to Article 72.4 of The International Code of Zoological Nomenclature, this specimen is to be considered as part of the type series, for it was known to and labeled by Giordani Soika himself .

There are two additional male paratypes from Bolivia mentioned by Giordani Soika (1990), but they were not found among the type series of S.humerale . Giordani Soika was known to retain specimens in his private collection, as cited in his own papers (e.g., Giordani Soika, 1990: 158), and common depositories are the two presently studied collections. Until these two specimens are found and properly studied, they remain as paratypes of S. humerale , whose type series is currently composed by four specimens.

Examined Type Material. Bolivia, Mapiri: holotype female ( MSNVE), ‘Mapiri\Bolivia’ ‘60’ ‘64’ ‘velutinum\Ducke’ ‘ Holotypus \ Stenosigma \ humerale ’ (red label) ‘clipeo’ (handwriten label). Bolívia, Coroico: allotype male ( MSNVE), ‘Coroico\Bolivia’ ‘ ♂ ’ ‘ Allotypus \ Stenosigma \ humerale ’ (red label) ‘clipeo’ (handwriten label).

Figures

Figs. 1–9. Stenosigma humerale holotype female. 1, habitus; 2, lower head in lateral view; 3, lateral surface of pronotum in lateral view; 4, mesepisternum; 5, mesoscutum and scutellum in dorsal view; 6, metanotum in dorsal view; 7, T1 in dorsal view; 8, T1 in lateral view; 9, S1 in ventral view. Scale bars for Fig. 1 = 2 mm, Figs. 2–4 =0.5 mm, and Figs.5–9 =1 mm.

Figs. 10–12. Labels attached to the putative female paratype of S. humerale, presently attributed to a new species.