Hedychrum Latreille

Lucena, Daercio A. A., Santos-Neto, Pedro E., Zanella, Fernando C. V. & Almeida, Eduardo A. B., 2022, Taxonomic review of the elampine cuckoo wasps from northeastern Brazil (Hymenoptera: Chrysididae), with the description of three new species, Zootaxa 5213 (3), pp. 201-235 : 211

Genus Hedychrum Latreille

This genus contains more than 150 described species. These wasps are distributed in all biogeographic realms but the Australian region ( Kimsey & Bohart 1991). Like other Elampini , the highest diversity of Hedychrum is found in the Palearctic region, where the most alluringly bicolored species are found. Some Hedychrum species are known as cleptoparasites of beewolves ( Crabronidae : Philantinae) (e.g., Strohm et al. 2008 and references therein). There is no record of hosts for the Neotropical species. This genus is easily distinguished from other elampine genera in South America based on the following combination of characteristics: inner surface of meso- and metatibiae with distal fovea; hypostoma with medial process; tarsal claw with single subsidiary tooth; female S3 with small medial process; T3 with discrete pre-apical swelling; T3 distal rim angulate basolaterally; and the male metafemur expanded dorsoventrally, with its anterior surface reticulate, non-metallic, dark brown. Gender determination in Hedychrum is comparatively much simpler than other Elampini . Females are easily identified based on presence of apicomedial tooth in the S3. Males are easily distinguished based on the anterior surface of the metafemur, which is reticulate and non-metallic brown. Distinction among the species in Hedychrum tend to be hard because the genus is very conserved morphologically. Differences in the most diagnostic features are subtle, such as flagellomere lengths, relative lengths of other body parts, vestiture, and sculpturing ( Kimsey & Bohart 1991).

According to Ducke (1913) and Kimsey & Bohart (1991), two species are recorded to Brazil: H. brasilianum Dahlbom, 1854 , and H. neotropicum Mocsáry, 1889 . We have examined specimens collected in different localities across various Brazilian regions and biomes, and all had been identified as H. neotropicum . The type-depository of H. neotropicum was listed as doubtfully deposited in MLUH by Kimsey & Bohart (1991). We have located and examined images of the holotype of this species hosted at MLUH. Mocsáry (1889) indicated that the holotype was a male had been collected in Nova Friburgo (Rio de Janeiro state, Brazil). Later, L. French labelled the holotype as female. We have examined two female specimens in MZSP from Caraguatatuba (MZSP 04567) and Ubatuba (MZSP 04568) (north coast of the São Paulo state, about 400 km south from the type locality of H. neotropicum ), which precisely match with the description of H. neotropicum . Based on the examination of the holotype images and those females from São Paulo state, we concluded that most specimens previously identified as H. neotropicum from different regions in Brazil represent similar, although distinct species. Future taxonomic research will be needed to sort out the diversity of H. neotropicum and closely related species in South America. We did not locate any specimen identified as “ Hedychrum brasilianum Dahlbom ” in Brazilian collections. Rosa & Xu (2015) provided images for the holotype of H. brasilianum , housed at MRSN, and collected at an unknown locality in Brazil. Although the holotype was severely damaged (lacking the head, legs, and the ventral surface of the metasoma), its images made clear that the specimens we analyzed from northeastern Brazil do not belong to this species. Herein, we describe a new species from northeastern Brazil.