Pista Malmgren, 1866

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 45-47

Pista Malmgren, 1866

Malmgren, 1866:382. Hessle, 1917:153, Tex-Fig. 34.— Saphronova, 1991:243–244. Hartmann-Schröder, 1996:519.— Hilbig, 2000:267.

Synonyms: Idalia de Quatrefages, 1866 (preoccupied by a Lepidoptera genus); Otanes Kinberg, 1867 ; Scionopsis Verrill, 1873 .

Type species: Amphitrite cristata Müller, 1776 , by original designation.

Diagnosis: Branched branchiae on segment 1, 2, 2–3, or 1–3; eyespots sometimes present; lateral lappets on segments 1–4; ventral shields from segment 2 or 3; nephridial papillae sometimes on segment 3, always on segments 6–7; 17 pairs of notopodia from segment 4, notochaetae smooth, bilimbate; neuropodia from segment 5, uncini avicular, with short or long posterior process, in single rows on segments 5–10; in double rows, face to face, until segment 20; thereafter in single rows.

Remarks: Pista has been considered a problematic genus, because of the heterogeneity of the species morphology. Smith (1992) showed this heterogeneity describing three different nephridial systems in this genus, one pair of anterior excretory nephromixia and two pairs of separate thoracic reproductive nephromixia with genital papillae, on segments 6–7. These morphological problems have suggested that some species have wide distributions. The identity of the type species, P. cristata , has been interpreted differently by some authors ( Müller, 1776; Malmgren, 1866), and has been considered a cosmopolitan species. Hence, it has been treated as a species complex ( Saphronova, 1991). Six species have been recorded from the Grand Caribbean ( Salazar-Vallejo, 1996), but only one, P. sombreriana McIntosh, 1885 , from St. Thomas, Lesser Antilles, was originally described from there. Pista papillosa ( Tourtellotte & Kritzler, 1988) , from the Gulf of Mexico, is herein transferred to Pistella Hartmann-Schröder, 1996 as it has uncini without a posterior process (see below). The other recorded species were described from New England, northwestern Atlantic ( P. palmata ( Verrill, 1873)) , from Norway ( P. cristata ), from the Red Sea ( P. fasciata (Grube, 1870)) , and from southwestern Africa ( P. quadrilobata ( Augener, 1918)) . Three more new species are present in the Caribbean ; they will be discussed in a forthcoming revision of the genus by the author.

Hilbig (2000) and Smith (1992) introduced important information about the methyl green staining pattern in some species of Pista from California. This was one of the first attemps at using other characters to identify species in this genus.