New Species and Records of Costa Rican Featherwing Beetles (Coleoptera: Ptiliidae) Darby, Michael Zootaxa 2016 4184 1 41 51 47RLR [151,359,1865,1891] Insecta Ptiliidae Nossidium GBIF Animalia Coleoptera 1 42 Arthropoda species issyae sp. nov.  Habitus Fig. 3Aa/b. Length 0.96 mm. Body yellowish brown covered with grey/yellow overlapping pubescence, legs and antennae dusky yellow. Antennomeres 3–8 length 0.4 mm; antennomeres 4–8 elongate, 10,11 globular, with sensillae. Width across eyes 0.38 mm. Mentum broadest at anterior margin tapering towards base, two longest setae situated medially on lateral margins, Fig. 3F. Pronotum length 0.33 mm, width 0.63 mm, posterior margin sinuate before the angles. Elytra length 0.56 mm, width 0.63 mm, widest just behind humeri. Wings of usual  Nossidium type, Fig. 3H. Mesoventral collar reaching onto the humeri with a raised anterior border and a vertically oriented medial ridge, Fig. 3G; mesoventral keel wide between the mesocoxae, Fig. 3D. Metaventrum short, pubescence denser on disc, posterior intercoxal process comprised of two short, sharp points, Fig. 3E.  Male: not known.  Female: spermatheca globular, Fig. 3C.   Etymology. Named after Miss Isobel 'Issy' Millett, a close friend of the author’s family.   Diagnosis. The new species may be separated from  N. schuelkei sp. n.and  N. katyaeby the form of the mesoventral keel which does not extend below the mesocoxae. In this respect it is similar to  N. pilosellum, and the North American species  N. americanumMotschulskyand  N. amoenumMotschulskybut these are less rounded and more parallel sided species.     Typedata. Holotype: ♀, Costa Rica,  Alajuela, Peñas Blancas,  820m,  19 May 1989, J. Ashe, R. Brooks, R. Leschen; Snow Entomological Museum,  CostaRican Expedition,#279; ex. with ants under bark (MM). Fragmentsof a second specimen from the same locality, ex. Xylaria,  17 May 1989, mounted as a slide, are also in MM. 1324562324 [199,624,332,357] Costa Rica Costa Rica 3 44 1 1 holotype 1324562315 1989-05-19 J. Ashe & R. Brooks & R. Leschen & Snow Entomological Museum Costa Rica 820 Penas Blancas 3 44 1 Alajuela holotype 1324562319 1989-05-17 J. Ashe & R. Brooks & R. Leschen & Snow Entomological Museum Costa Rica 820 Xylaria Fragments 3 44 1 Costa holotype