Three new species of Heteragrion Selys, from Brazil with redescription of the holotype of H. Dorsale Selys (Odonata, Megapodagrionidae)

Abstract

Erected by SELYS (1862) the genus Heteragrion was reviewed by WILLIAMSON (1919) who described and listed 29 species. At the same time SJÖSTEDT (1918) and RIS (1918) described seven species. Only fourty seven years later another species was described, by DONNELY (1965). As concerns the species originally described from Brazil, SELYS (1886) described H. obsoletum Selys, 1886 and, only 102 years later (MACHADO 1988), appeared the description of another Brazilian species, H. petiense Machado, 1988 followed by H. muryense Costa & Santos, 2000. These enormous gaps in Heteragrion descriptions cannot be explained by its rareness, for the species of the genus are not difficult to find in the field and are abundant in collections. It can be better explained by the difficulty in establishing the identity of many species, in special those of Selys group 2, so far described with vague and incomplete data, with innacurate or entirely missing illustrations. This situation has prompted studies of the types of these species, as already done by DE MARMELS (1987, 2004 for Sjöstedt species and for H. macilentum Hagen in Selys, 1862 and by WILLIAMSON (1919) for some of Selys and Hagen species. Following the same research line, we now redescribe the holotype of H. dorsale Selys, 1862 borrowed from Sely's collection at Brussels and hitherto know only from Selys description. We also describe three new species of Heteragrion from South and Southeastern Brazil. With them, the number of known species of Heteragrion goes to 46, 20 of which from the Brazilian fauna.

List of Odonates from the Floresta Nacional de São Francisco de Paula (FLONA - SFP), with two new distribution records for Rio Grande do Sul, Brazil

“…2.2. Heteragrion luizfelipei Machado, 2006 This species (Figure 3b) have its current distribution restricted to southern and southeastern Brazil, from São Paulo (Machado, 2006), and Paraná to its southern limit in the Santa Catarina state as reported by Lencioni (2013). Here we expand the distribution around 250 km southwards in the Rio Grande do Sul state.…”

“…We found two new records of odonate species for Rio Grande do Sul, one belonging to Libellulidae: Libellula herculea Karsch, 1889; and one belonging to Heteragrionidae: Heteragrion luizfelipei Machado, 2006. …”

First record of Heteragrion cooki from Peru (Odonata: Heteragrionidae)

“…2c). Heteragrion dorsale Selys, 1862, is the one group A species for which information on the caudal appendages is lacking as the type material has lost that section (Machado 2006). However, the thoracic pattern provides char- acters to differentiate it from other species.…”

“…However, the thoracic pattern provides characters to differentiate it from other species. Heteragrion cooki lacks of stripes over the metepisternum and metepimerum, a typical character in H. dorsale ( Machado 2006). Moreover, the specimen has the mesepisternum dark brown dorsally, mesepimerum brown dorsally, dull yellow ventrally, and metepimerum yellow with a dark dash distally, clearly matching the pattern described for H. cooki by Daigle & Tennessen (2000) ( cf.…”

“…Classification of Heteragrion groups and terminology follows Lencioni (2013). After determining which group the specimen corresponded to, several references, including Daigle & Tennessen (2000), De Marmels (2004), Machado (2006), Lencioni (2013), Machado & De Souza (2014), Machado (2015), Ávila-Junior et al (2017), and Vilela et al (2019) were used for species identification.…”