Polymastigos Green, 2002

Silva, Camila Fernanda Da & Amaral, Antonia Cecilia Zacagnini, 2022, Capitellidae (Annelida) from the Brazilian Continental Margin (SW Atlantic): new occurrences of three genera and description of new species, Zootaxa 5104 (1), pp. 89-110 : 102-103

Genus Polymastigos Green, 2002 , amended

Type species: Polymastigos reishi Green, 2002: 327–329 , fig. 29A–H.

Type locality: Andaman Sea , Thailand, Indian Ocean .

Generic diagnosis. (amended after Magalhães & Blake 2020). Prostomium conical, palpode present; eyespots absent. Peristomium clearly distinct from prostomium; achaetous segment absent. First chaetiger uniramous or biramous. Eleven thoracic chaetigers. Chaetigers 1 to 10 with only capillaries; neuropodia of chaetiger 11 may bear capillaries or hooded hooks. Transition between thorax and abdomen can be clearly demarcated or subtle. Two or more abdominal segments with notopodial capillaries and neuropodial hooded hooks; remaining abdominal segments with only hooded hooks. Branchiae may be present. Intersegmental genital pores in a pair from chaetiger 7 up to chaetiger 13. Lateral organs present in thorax and abdomen. Pygidium may bear a mid ventral cirrus.

Remarks. Abdominal segments with notopodial capillaries and neuropodial hooks are not very common among capitellid genera, but it had been already reported for Leiocapitellides Hartmann-Schröder, 1960 , Leiochrus Ehlers, 1908 , Paracapitella Kirkegaard, 1983 , Promastobranchus Gallardo, 1968 , Pseudoleiocapitella Harmelin, 1964 , and Polymastigos Green, 2002 . The latter genus was erected by Green (2002) based on specimens collected offshore the Andaman Sea, Thailand. Polymastigos reishi Green, 2002 is characterized by having 11 thoracic chaetigers bearing capillary chaetae in both rami, thorax uniramous, at least the first six abdominal chaetigers with capillary chaetae in notopodia and hooded hooks in the neuropodia, and the remaining abdominal chaetigers with hooded hooks in both rami. A second species, collected on mangroves from Central Java, Indonesia, was recently described in Pamungkas (2015), Polymastigos javaensis Pamungkas, 2015 , differing from the type species by the thorax biramous, the shape of the abdominal segments, hooks, number of abdominal segments with capillaries, and the methyl green staining pattern. Both known species of Polymastigos are from intertidal areas or shallow waters, differing from the new species described here (990–1361m). The diagnosis was modified to include some variations on the generic characteristics, because when Green (2002) erected it there was only one species. Polymastigos javaensis , for example, has first chaetiger biramous and, as the specimens were complete, it was possible to observe branchiae and pygidium with a ventral cirrus. The three species differ on the number of abdominal chaetiger bearing capillaries; and P. profundus sp. nov. presents transition between thorax and abdomen subtle, not clearly demarcated, and neuropodia of chaetiger 11 with hooded hooks. All species bear genital pores from chaetigers 7 and 8 and the new species bear genital pores up to chaetigers 12 and 13 instead of chaetigers 10 and 11, as the already known species.