A new species and new recorded species of Orbiniidae Hartman, 1942 (Annedia: Polychaeta) from China

A new species of the orbiniid genus Phylo, P. heterochaetus sp. n., is described based on material collected from northern Yellow Sea, China. This is the thirteenth species in Phylo Kinberg, 1866. The new species can be easily identified by the combination of the following characters: anterior thorax with 13 setigers, interramal cirri absent, anterior thoracic neuropodia with 4–5 rows of uncini, intermixed with few subuluncini in the first 1–2 rows, ventral fringe of numerous of stomach papillae present on setigers 12–24. We also described and illustrated P. fimbriata, which is recorded for the first time from China seas.


Introduction
Phylo Kinberg, 1866belongs to Orbiniidae Hartman, 1942 and differs from the other genera in having species with modified spines on posterior thoracic setigers.
The genus Phylo is mainly characterized by the following characters: branchiae first present from chaetiger 5-7, thoracic neuropodia fringed, with several postchaetal lobes, posterior thorax and anterior abdominal setigers with subpodial lobes, usually forming ventral fringe, thoracic neurochaetae including blunt uncini or subuluncini and crenulated capillaries; posterior thoracic setigers with modified spines.
The present specimens, which collected from northen Yellow Sea. clearly belong to the genus, according to the characters listed above. They were identified as a new species, which is described and illustrated in this study. Additionally, we described and illustrated P. fimbriata based on species collected from East China Sea. This is the first discovery of this species from Chinese waters.

Material and Methods
Material checked in this study are collected from northern Yellow Sea and East Prostomium short, conical, tapering to rounded tip. Eyepots absent, nuchal organs narrow groove at junction with peristomium ( Fig. 1). Peristomium a narrow asetigerous segment, distinctly separated from prostomium and setiger 1, mouth with anterior oral lip arising from posterior margin of peristomium, posterior oral lip from anterior margin of setiger 2. Holotype with proboscis everted, consisting of two large, inflated lobes ( Thoracic notopodia with fascicles of crenulated capillaries. Adominal notopodia with less long, thin capillaries, 2-4 furcate chaetae and 3-5 imbedded aciculae, furcate chaetae with unequal tynes, each tyne with fine needles directed medially, shaft with transverse rows of barbs (Fig. 3E).
Variation. One paratype (MBM286986) with 13 and 14 anterior thoracic setigers on left and right side respectively, posterior thorax with 9 and 8 setigers respectively.
Etymology. The species is named for the thoracic neuropodia with two kinds of uncini.
Both thoracic notopodia and neuropodia with fringed postchaetal lobes, notopodium half as broad as the neuropodium, broadly palmate (Fig. 4A, 5A). Notopodia with single conical postchaetal lobe from chaetiger 1, increasing gradually to about 6 lobes on posterior thoracic setigers, postchaetal lobes equivalent in size and shape on anterior setigers, with inner lobe separate and becoming longer than the outer ones on the posterior setigers (Fig. 4A, C). Abdominal notopodial postchaetal lobe arising from narrow base, broadly triangular (Fig. 4B).
Distribution. East China Sea (China); Suruga Bay, Miyagi Prefecture (Japan). (Moore, 1903), the species which was first recorted by Moore (1903) from Suruga Bay and North Japan, unlike most species of Phylo, thoracic notopodia has fringed postchaetal lobes. Okuda (1937) redescribed this species based on specimens from Miyagi Prefecture. The morphology of present specimens agrees well with original description of specimens from Japan. Fig. 1 anterior end of Phylo heterochaetus sp. n. Scale bar: 2mm.