Pycnoderma Grube, 1877 Pycnoderma Grube, 1877b:540; Hartman, 1965:62; Day, 1967:655 –656. Diagnosis emended. Body cylindrical. Tunic thick, opaque, or transparent. Cephalic cage well developed; notochaetae dorsal, sometimes very long. Anterior margin of chaetiger 1 papillate, without dorsal projection. Body papillae often minute, abundant over the body, sometimes arranged in rows. Posterior noto- and neurochaetae with few, long articles (oligo-articulated). Posterior neurospines with few articles, distal articulation short and blunt, elongate and thin, or short and foliose-aristate. Branchiae cirriform, arising over a tongue-shaped branchial plate. Type species. Pycnoderma congoense Grube, 1877, by monotypy. Remarks. The original diagnosis (Grube 1877b:540) was: “Corpus vermiforme, gracile, cute densa, hyaline, papillis minimis obsita, segmentis numerosis. Fasciculi setarum utrinque distichi, setae superiors et inferiors capillaries, dense annulatae, segmentorum anteriorum aliquot protentae, ceteris longiores. Branchiae filiformes, segmento buccali affixae, lobus capitalis, tentaculata retahenda.” Its translation would be: Body worm-shaped, slender, skin dense, hyaline, papillae small contained (within the tunic), many segments. Chaetal fascicles paired, lateral, superior and inferior chaetae capillaries, densely annulated, anterior segments directed forwards, others long. Branchiae filiform, fixed in mouth segment, head lobe (and) tentacles retractile. As herein defined, Pycnoderma includes, besides the type species, P. congoense Grube, 1877, P. dannyi n. sp., P. escobarae n. sp., P. ferruginea (Gallardo, 1968) n. comb., P. g l a b r a (Treadwell, 1901) n. comb., P. g l a s b y i n. sp., P. gracilis (Hartman, 1961) n. comb., and P. talehsapensis (Fauvel, 1932) n. comb. On the other hand, P. f e rnandense Augener, 1918, described from two localities in Ghana and in Equatorial Guinea, has anchylosed neurohooks in posterior chaetigers and therefore must be referred to Trophoniella.

Published as part of Salazar-Vallejo, Sergio I., 2011, Revision of Piromis Kinberg, 1867 and Pycnoderma Grube, 1877 (Polychaeta: Flabelligeridae), pp. 1-50 in Zootaxa 2819 on page 30, DOI: 10.5281/zenodo.277211