First records of Synoeca septentrionalis Richards, 1978 (Hymenoptera, Vespidae, Epiponini) in the Brazilian Atlantic Rain Forest

Abstract Nests of Synoeca septentrionalis were collected in two Brazilian Atlantic Rain Forest localities (Itabuna and Santa Terezinha, in the state of Bahia and Alfredo Chaves in the state of Espírito Santo). Synoeca septentrionalis was previously recorded only from Central America and northwestern South America. This findingextends its geographical distribution to Northeast and Southeast regions of Brazil, and represents the first record for Synoeca septentrionalis in the Brazilian Atlantic Rain forest, raising to three the number of Synoeca species known from Bahia State.


Introduction
Synoeca is a small genus of social wasps, with five species described, widely distributed in Central and South America (Richards 1978;Carpenter and Marques 2001). The nest architecture is similar in all species: arboreal, usually on a broad slanting surface and with a single sessile comb attached directly to the tree trunk (Wenzel 1998). The genus was recently subject of a phylogenetic analysis, being supported as monophyletic (Andena et al. 2009).
The nests collected present a longitudinal groove extending from top to bottom, and a central-dorsal ridge (Fig. 1). Richards (1978: 181) reported similar nests features in S. septentrionalis collected in Cali (Colombia). The nest of S. surinama is similar to S. septentrionalis with a central-dorsal ridge (Castellon, 1980: fig. 5). However, nest of S. surinama has a keel instead of a groove. The nests were found attached to tree trunks (Santa Terezinha c. 1,70 m from the ground and two combs; Itabuna c. 6 m from the ground and one comb) and attached on the rock (Alfredo Chaves c. 2,10 m from the ground and two combs). Elisei et al. (2005) and Sidnei Mateus (pers. com.) also recorded nests of S. cyanea attached on the rock in the states of Minas Gerais and Mato Grosso.
Synoeca septentrionalis is easily diagnosed by the presence of the outstanding erect hairs on the first metasomal tergum and sternum and by a dark triangular area in clypeus (Richards 1978;Andena et al. 2009). However, variation in the clypeus color pattern was observed. The nest collected in Santa Terezinha had eight females with clypeus entirely reddish, two females with clypeus reddish with a dorsal dark area, eight males with clypeus reddish with a triangular dorsal dark area, and five males with the clypeus reddish with a dark dorsal area. The specimens collected in Alfredo Chaves (eigth females) and Itabuna (14 females) had the clypeus entirely reddish. Richards (1978: 181) also reported variation in clypeus color in specimens collected in Ecuador and Colombia.
Voucher specimens are deposited at Entomological Collections at the Universidade Estadual de Santa Cruz, Ilhéus, Brazil and at the Universidade Estadual de Feira de Santana (MZUEFS), Feira de Santana, Brazil. Despite the male genitalia have been cited by Richards (1978) and used in a phylogenetic analysis by Andena et al. (2009) we also provided detailed drawings of this structure (Fig. 2).
This finding extends geographical distribution of S. septentrionalis to Northeast and Southeast regions of Brazil, and represents the first record for S. septentrionalis in the Brazilian Atlantic Rain forest, raising to three the number of Synoeca species known from Bahia State, S. cyanea (Richards 1978;Santos et al. 2007), S. surinama (Richards 1978), and S. septentrionalis.
Geographic distribution of other Epiponini, Epipona media Cooper, previously described to range from Ecuador, Peru and Brazilian Amazon to the state of Goiás was recently extended to Atlantic Rain Forest by Menezes et al. (2010). These data suggest that more exhaustive sampling in this region are needed to provide a diagnosis of the distribution of species, and a frame of the diversity in the biome of Atlantic Rain Forest for its preservation.