The adults of Camelobaetidius janae Dominique & Thomas, 2001 and C. yacutinga Nieto, 2003, with a new synonym for C. leentvaari Demoulin, 1966 (Ephemeroptera: Baetidae) Author Boldrini, R. Author Jacobus, Luke M. Author Salles, F. F. Author Pes, A. M. O. text Zootaxa 2013 3702 2 150 158 journal article 10.11646/zootaxa.3702.2.4 adf2a9ca-1628-4028-b99d-beac7d0ce6e7 1175-5326 217760 42A262A2-959D-4AB5-B493-98F66CE87775 Camelobaetidius leentvaari Demoulin, 1966 ( Figs. 14–15 ) Camelobaetidius leentvaari Demoulin 1966: 9 ; Traver & Edmunds 1968: 674; McCafferty & Waltz 1990: 783; Lugo-Ortiz &McCafferty 1995: 178; Dominique et al . 2001a: 40; Dominique et al . 2002a: 18; Thomas et al . 2003: 124; Salles et al. 2005a: 52; Salles et al . 2005b: 70; Salles & Serrão 2005: 276; Domínguez et al . 2006: 131; Boldrini & Salles 2009: 6; Boldrini et al . 2010: 65; Nieto 2010: 12; Nieto et al . 2011: 4; Boldrini et al . 2012b: 2057. Camelobaetidius mantis Traver & Edmunds 1968: 675 . nov. syn. Diagnoses . Nymph : 1) segment II of labial palp with distomedial projection strongly produced; (2) forefemur with prominent protuberance on inner margin; (3) foretibia with indentation at apex; (4) small thoracic gill present at the base of the forecoxa; (5) prosternum with a single, medial protuberance; (6) tarsal claws with 17–28 denticles; (7) paraproct with 5–17 small marginal spines. Distribution . Surinam (Demoulin, 1966); Venezuela (Nieto et al . 2011). Brazil : Amapá (Salles et al . 2005b), Amazonas (Traver & Edmunds, 1968). Comments . Demoulin (1966) described the nymphs of C. leentvaari , the type species of the genus. He overlooked some characters, including the number of denticles on the tarsal claws. Two years later, Traver and Edmunds (1968) described C. mantis , a species very similar to C. leentvaari . Nymphs of both species have segment II of the labial palp with a strongly produced distomedial projection, the forefemur with a prominent protuberance on its inner margin, the foretibia with an apical indentation, and the terminal filament reduced. Traver and Edmunds (1968) distinguished C. mantis from C. leentvaari by the number of denticles on tarsal claws (25 denticles in C. mantis and nine denticles in C. leentvaari , which were visualised and counted in the drawing made by Demoulin, 1966); by the shape of the protuberance on the inner margin of the forefemur (more acute in C. mantis ); and by the trachea and lateral branches of the gills being pigmented in C. mantis and unpigmented in C. leentvaari . Later, Salles et al . (2005b) redescribed C. leentvaari based in the type material and additional material from Brazil . They examined the number of denticles on the tarsal claws and noted that the actual number ranged from 17–23; they also described the presence of a single medial protuberance on the prosternum for this species. After examination of the C. mantis holotype , we noted that this species also has a single medial protuberance on the prosternum. Very slight differences in the shape of the prominent protuberance on the inner margin of the forefemur and the pigmentation of abdominal gill tracheae, as well as differences in the number of denticles on the tarsal claws (25 on C. mantis , 17–28 on C. leentvaari ) are easily attributable to natural variation. Greater variation has been documented within other species, such as the Nearctic C. musseri (Traver & Edmunds, 1968) (McCafferty & Randolph, 2000) ; thus, we consider C. mantis to be a junior synonym of C. leentvaari . FIGURES 14–15. Detail of prosternum of the mature nymph of Camelobaetidius leentvaari . 14, short thoracic gill at base of foreleg (ventro-lateral). 15, extremely short thoracic gill at base of foreleg (ventro-lateral). We also observed that some specimens of C. leentvaari from Amapá, Brazil , have an important variation in the length of the thoracic gill at the base of foreleg. While the thoracic gill at the base of the foreleg may be relatively short in general ( Fig. 14 ), one nymph in particular has an extremely short thoracic gill ( Fig. 15 ) that might be missed upon superficial examination. Thus, we emphasize the importance of careful examination of specimens for proper identification. Material examined . Two female mature nymphs, one male imature nymph and one female imature nymph, Brazi, Amapá, Oiapoque, Oiapoque river, Cachoeira Grande, 03°48'13.0" N / 51°52'31.2'' W , 9.viii.2011 , Pes, A.M.O., Cruz, P.V. Fernandes, A.S., Hamada, N. leg (INPA); holotype of Camelobaetidius mantis (PERC), one imature nymph, Brazil , Amazonas State, Rio Amazonas, 16.iii.1961 , Fittkau, E.J. leg. Acknowledgements We express our gratitude to CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for a fellowship to FFS and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for financial support of the Pro-Equipamentos CAPES. The authors would like to thank Dr. Neusa Hamada (Instituto Nacional de Pesquisas da Amazônia) for logistic support. Jen Zaspel and Arwin Provonsha (Purdue University) provided access to the holotype of C. mantis .