Phylo felix Kinberg, 1866

Zhadan, Anna, 2020, Review of Orbiniidae (Annelida, Sedentaria) from Australia, Zootaxa 4860 (4), pp. 451-502 : 487-489

Phylo felix Kinberg, 1866

Figures 21 , 22

Phylo felix Kinberg, 1866: 251–252 ; Hartman 1957: 262–265, plate 23, figs. 1–7; Day 1977: 234; Blake 2017: 90–93 , figs. 42–43.

Orbinia (Phylo) felix australis Hartmann-Schröder 1984: 33-34 .

Material examined. New South Wales: Cottage Point, Cowan Creek , 33°39’S, 151°10’E, 10.10.2004, intertidal, under boulders, coll. P.A. Hutchings, J.M. Nogueira, AM W.30718, 1 specimen ; same place, 17.04.2011, intertidal, Zostera , coll. P.A. Hutchings, AM W.32798, 1 specimen ; east of North Head, Port Jackson , 33°47’50”S, 151°18’57”E, 21.07.1989, depth 30 m, sand, coll. Fisheries Research Institute ( NSW), AM W.24306, 1 specimen . Western Australia: Little Grove, Princess Royal Harbour, Albany , 35°04’S, 117°52’E, 22.11.1975, fine sand with mollusk shells, coll. G. Hartmann- Schröder, AM W.198417, paratypes of O. (Ph.) felix australis , 2 specimens .

Type locality. Brazil .

Description. Body long, thorax flattened, abdomen cylindrical; thoracic width 1.6–2.8 mm ( Figs 21A , 22A, E ). Prostomium conical with pointed but not sharp tip ( Figs 21C , 22A, D, E ). Thoracic chaetigers numbering 18–20. Branchiae from chaetiger 5, triangular with tapering tips, in abdomen becoming long triangular and strap-like, shorter than notopodia ( Figs 21C, E, G, H , 22A, B, D, F ). Thoracic notopodial postchaetal lobes developed from first chaetiger, digitate to narrow foliaceous; in abdomen becoming very long, foliaceous, in posterior segments narrow, cirriform ( Figs 21C, E, G, H , 22A, B, D, F ). Thoracic neuropodial postchaetal lobes as ridge with up to 8 papillae; subpodal papillae present from chaetigers 13–18 to 21–24, up to 14 per parapodia; in larger specimens reaching midventral line in 3–4 segments ( Figs 21B, D, E, F , 22B, C, E ). Abdominal neuropodia bilobed, with subequal lobes or outer lobe slightly larger; subpodal flange well developed, with long papilla (ventral cirrus) ( Figs 21G, H , 22F ). Interramal cirrus present, longer than neuropodia, starting from last 3–4 thoracic segments ( Figs 21E, G, H , 22B, F ). Pygidium with two anal cirri ( Fig. 21A ). Notopodial chaetae crenulate capillaries, in abdominal notopodia also forked chaetae present ( Fig. 21G, H ). Thoracic neuropodia bearing 3–4 rows of curved smooth uncini and few thin capillaries in posterior row; beginning from chaetiger 12–13 in anterior row very thick dark straight spear-like spines present, up to 7 spines per parapodia ( Figs 21 D-F, 22A, D). Abdominal neuropodia bearing capillary chaetae; both rami supported by thin straight aciculae in abdomen ( Fig. 21G, H ).

Distribution. (based on literature). Brazil, Patagonia, Gulf of Mexico, Pacific coast of South America, Gulf of California, Antarctica, Japan, New Zealand, Australia (Queensland, New South Wales, Victoria, Western Australia).

Habitat. Intertidal and upper subtidal, sand, shells, seagrass.

Remarks. Phylo felix was described from Brazil, after which it was recorded from around the Pacific, including the coast of South America, Gulf of California, Japan, New Zealand, and Antarctica (Hartman, 1957; Day, 1977; Blake 2017). The subspecies Orbinia (Phylo) felix australis was described from Western Australia. It differs from the nominal species owing to the following characteristics: modified spines starting from chaetiger 13 instead of 11; subpodal papillae present after chaetiger 20, usually they cover chaetiger 22–25 instead of 17–20; and interramal cirri starting from the last 3–7 thoracic chaetigers instead of 2. According to these characters, the specimens investigated in the present work are similar to the subspecies Orbinia (Phylo) felix australis , but demonstrate an intermediate state in some specimens. For example, the modified chaetae start from chaetiger 12, the subpodal papillae extend to chaetiger 21, and there are 3 thoracic segments with interramal cirri. This indicates an absence of a clear border between the nominal species and Ph. felix australis . The validity of this and other subspecies should be confirmed by careful investigations of morphological and/or molecular characters.

Figures

FIGURE 21. Phylo felix. A–D: AM W.30718, stereomicroscope.A. General view; B. Thorax-abdomen transition, lateral view; C. Anterior end, dorsal view; D. Posterior thoracic chaetigers, lateral view; E–H, AM W.24306, compound microscope. E. Parapodium of chaetiger 17; F. Neuropodium of chaetiger 17; G. Parapodium of chaetiger 23; H. Posterior parapodium. a, acicula; br, branchia; cc, crenulated capillaries; fc, forked chaeta; flc, flail chaeta; ic, interramal cirrus; ne, neuropodium; no, notopodium; ss, spear-like spines; u, uncini.

FIGURE 22. Phylo felix. AM W.198417, paratypes of Orbinia (Phylo) felix australis; stereomicroscope, methylene blue staining; A. Anterior part of the body, dorso-lateral view; B. Thorax-abdomen transition, dorso-lateral view; C. Anterior part of the body, ventral view; D–F: another specimen. D. Anterior part of the body, dorso-lateral view; E. Anterior part of the body, ventral view; F. Abdomen, dorso-lateral view.