New species and new stage descriptions of Campsurus major species group (Polymitarcyidae: Campsurinae), with first report of silk-case construction in mayfly nymphs

Abstract

Campsurus major, C. argentinus and C. amapaensis sp. nov. form a monophyletic group supported by the following apomorphies in the male genitalia: robust pedestals with a widely rounded inner-posterior margin and a more acute and thinner outer margin, penes strongly sclerotised and curved ventrally, each lobe twisted outwards, and with a small membranous lobe on ventral margin. The nymphs of Campsurus major and C. argentinus and the female adult of C. major are described for the first time and illustrated here; the male adults of both species are redescribed. A new species, C. amapaensis, is described from male imagos. The following new synonymies are proposed: Campsurus argentinus Esben-Petersen (= C. pallidus Needham & Murphy, junior synonym) and C. major Needham & Murphy (= C. brasiliensis Traver, junior synonym). The nymphs of both species are reported to use silk to build soft cases and to glue substrate particles. A list of characters useful to distinguish the treated species from others in the genus is given.

Keywords:

• Campsurus argentinus
• C. brasiliensis
• C. pallidus
• C. amapaensis
• Ephemeroidea
• case-building
• silk

Acknowledgements

We are grateful to Janice G. Peters (FAMU) for permanent help and support during the course of this study. Thanks also to Lucimar Gomes Dias and Iracenir Santos Andrade for the loan of material from Amapá. Richard Hoebeke and James Liebher kindly attended our interest in studying the types at CUIC. Financial support from Pedeciba-Biología (Naciones Unidas Proyecto URU/06/004), CONICET (PIP 1484) and ANPCYT (PICT 528, 351) is greatly acknowledged.