Phylo Kinberg, 1866

Blake, James A., 2017, Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America, Zootaxa 4218 (1), pp. 1-145 : 90

Genus Phylo Kinberg, 1866

Type-species: Phylo felix Kinberg, 1866 , by monotypy.

Diagnosis. Prostomium pointed on anterior margin; peristomium with one achaetous ring. Branchiae first present from setiger 5–7. Posterior thoracic segments with several postsetal lobes and subpodial lobes (at least five of each type) together usually forming ventral fringe. Thoracic neurosetae including blunt uncini and crenulated capillaries; posterior thoracic segments with modified spearlike spines. Flail setae present or absent in posterior abdominal notopodia.

Remarks. Species of Phylo are closely related to species of Orbinia and differ chiefly in having the thoracic region divided into anterior and posterior regions; the posterior region bears modified spines. Phylogenetically, the modified thoracic spines are apomorphic rather than plesiomorphic but provide species of Phylo with an obvious and practical distinctness that makes them easy to identify. Because of this character, Phylo is retained as a genus, although subgeneric rank with Orbinia might be preferred by some investigators. Ten species of Phylo were reviewed by Hartman (1957), who provided detailed descriptions for three, including the type species, P. felix Kinberg. Additional species have been described by Day (1961; 1977), Wu (1962), Mohammad (1970), and Hartmann-Schröder & Rosenfeld (1990). Phylo felix was encountered in the present study and appears to be limited to South America and the Antarctic Peninsula. Orbinia (Phylo) minima described from the Antarctic Peninsula by Hartmann-Schröder & Rosenfeldt (1990) is represented only by small specimens but agrees well with P. felix .