Phylo felix 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 : 90-93

Phylo felix Kinberg, 1866

Figures 42–43

Phylo felix Kinberg, 1866: 251 –252; Hartman 1948: 105 –106, pl. 15, fig. 10; 1953: 37–38; 1957: 262–265, pl. 23 (synonymy); 1966: 10, pl. 2, fig. 4 (synonymy).

Aricia michaelseni Ehlers, 1897: 88 –91, pl. 6, figs. 136–140; 1900: 12; 1901: 166. Fide Hartman 1948.—Not Monro 1930: 144 –145, fig. 54; Okuda 1937: 101; Berkeley & Berkeley 1952: 96, figs. 194–196.

Orbinia (Phylo) michaelseni: Pettibone 1963: 282 , fig. 75f.

Orbinia felix: Hobson & Banse 1981: 29 .

Phylo felix heterosetosa Hartmann-Schröder, 1965: 192 –194, figs. 176–177; Rozbaczylo 1985: 130. New synonymy.

Phylo kupfferi: Hartman 1967: 107 –108 (in part); Rozbaczylo 1985: 130 –131. Not Ehlers, 1874.

Phylo michaelseni: Rozbaczylo 1985: 131 .

Orbinia (Phylo) minima Hartmann-Schröder & Rosenfeldt, 1990: 106 –107, figs. 11–17. New synonymy.

Material examined. Uruguay: IBM Sta. N- 242, 63 m in sand (2, USNM 1013676 ) ; IBM Sta. N- 250, 83 m (7, USNM 1013677); IBM Sta. N-1066, 72– 86 m (1, USNM 1013678); IBM Sta. N-1073, 115– 117 m (1, JAB).— Argentina, offshore, R/V Vema Sta. V-18-12, continental slope E of Deseado, 424–428 m (2, LACM-AHF Poly 5036, 5044) ; V-17 -101, E of Mar del Plata, benthic trawl, 19 Jun 1961 (4, LACM-AHF Poly 5041).— Argentina, nearshore, San Antonio Bay , intertidal , 1 Jan 1973, coll. J.M. Orensanz (1, USNM 1013684); Marajada norte, high intertidal, 8 Feb 1971, coll. Panetta (5, USNM 1013685 ) ; Riacho Jabali, San Blas Bay , 4 Oct 1968, intertidal, muddy sand flats, coll. J.M. Orensanz (4, USNM 1013682 ) ; Mar del Plata , mussel bed, 19 Aug 1970, coll. J.M. Orensanz (1, USNM 1013683 ) ; Golfo San Matías, low intertidal, in gravel, IBM Sta. SAO-III-1 0 41 (1, USNM 1013680); IBM Sta. SAO-III-1048, intertidal (1, USNM 1013679); IBM Sta. N-1054, 58– 65 m, (1, USNM 1013675); IBM Sta. N-1059, 80– 72 m (1, USNM 1013674); IBM Sta. N-1073, 115– 117 m, (1, USNM 1407118); IBM Sta. N- 1074, 112 m (1, USNM 1013673); IBM Sta. N- 1075, 68 m (2, USNM 1013672; 1, USNM 1407117); Tierra del Fuego, Hero Sta. 651, 40 m (1, USNM 60642 ) ; Staten Island, Hero Sta. 659, intertidal (1, USNM 60643 ) ; Hero Sta. 665, 44 m (4, USNM 60644 ).— Falkland Islands, Teal Inlet , 2 Apr 1927, intertidal, coll. W.L. Schmidt (1, USNM 24431 ).—SE of Falkland Islands, R/V Vema Sta. M- 14- 12, 361 m (1, LACM-AHF Poly 5029). — Chile, Golfo de Quetalmahué , Isla Pullinque, N of Punta Ranqui , LUCE Sta. M-8B, Intertidal in mud (1, SMNH 154448 ) ; Golfo de Ancud, SW of Isla Tabon, LUCE Sta. M-44, ca. 200 m, fine sand mixed with clay (1, SMNH 154446 ) ; Seno Reloneavi, Isla Tenglo, the bay on the South Side , LUCE Sta. M-60 intertidal in sand (15, SMNH 154435 ) ; Seno Reloneavi, Piedra Azul, NW of Punta Quillaipe , LUCE Sta. M-16E, 30 m (5, SMNH 154445 ) ; Golfo Coreovado, Baja Vettor Pisani , LUCE Sta. 65A, 8 m, (1, SMNH 154443 ) ; Seno Reloneavi, E of Isla Guar, LUCE Stas. M-144, ca. 250 m, (1, SMNH 154436 ) ; same data, Sta. M-144A (1, SMNH 154439 ) ; Seno Reloneavi , Bahía Chincui, LUCE Sta. M-145, 70– 80 m, (4, SMNH 154438 ); SW of Valdivia, 39°59.9′S ; 74°01.5′W, 15 Mar 1960, 260 m, dredged, holotype of Phylo felix heterosetosa (ZMH P-14871).—Straits of Magellan, Punta Arenas, in sand, coll. Sep 1892, W. Michaelsen, syntype of Aricia michaelseni (ZMB 6764); Voillier Cove, 54°53′S, 69°38′W, 3 Feb 1896, 18 m, in sand, coll. E. Nordenskold (2, SMNH 1398); Puerto Tor, 55°67′S, 67°06′W, 11 Feb 1896, 36– 46 m, shell bottom with rocks, coll. E. Nordenskold (1, SMNH 1399); Puerto Eugenia, 54°56′S, 67°43′W, 12 Feb 1896, 18– 27 m, rocks with algae, coll. E. Nordenskold (2, SMNH 1400). — Antarctic Peninsula, Bismarck Strait , Hero Sta. 970, 102 m (1, USNM 60645 ) ; Bransfield Strait , Eltanin Sta. 6- 410, 220– 240 m (1, USNM 56452 ) ; South Shetland Islands, Eltanin Sta. 6-437, 267– 311 m (3, USNM 56453 ) .— Off Elephant Island, R/ V Walther Herwig Sta. 148, 61°12.7′S, 55°56.4′W, 134 m, holotype and 14 paratypes ( ZMH 19930-1 ) of Orbinia (Phylo) minima .

Description. A large species, one complete Chilean specimen 80 mm long, 2.9 mm wide, for 240 setigers; incomplete specimens larger, up to 92 mm long. Anterior fragments of 3.5 mm wide suggesting even larger specimens; Hartman (1948) recorded one of Kinberg’s fragmented specimens at 5 mm wide. Thorax with 15–19 setigerous segments; (1) anterior thoracic region with 10–12 setigers; (2) posterior region with 5–8 setigers.

Prostomium triangular, narrow, pointed on anterior margin depending upon preservation ( Figs. 42 A, 43A–B), peristomium a narrow asetigerous segment, smaller than setiger 1 ( Figs. 42 A, 43A–B); eyespots absent; nuchal organs narrow paired slits at border of prostomium and peristomium ( Fig. 43 B).

Thoracic notopodia, with elongate, fingerlike postsetal lamellae continuing through abdominal segments ( Figs. 42 A, 43B). Interramal cirrus present between noto- and neuropodia of posterior thoracic segments, continuing over most abdominal segments ( Fig. 42 C). Thoracic neuropodia with 2–3 postsetal lamellae from setiger 1, increasing to 9–12 over middle and posterior thoracic setigers ( Figs. 42 A, 43E); ventral fringe of numerous subpodial lobes or stomach papillae from setiger 11–14 ( Figs. 42 A, 43F), these beginning as 1–3 lobes increasing to 25 or more, nearly encircling ventral side of worm, abruptly absent from setiger 17–20, depending upon size of worms; abdominal neuropodia expanded apically, divided into two lobes; with a single ventral cirrus ( Fig. 42 C).

Thoracic notosetae including dense fascicles of crenulated capillaries and imbedded aciculae; abdominal notosetae including long, thin capillaries and 3–4 furcate setae; furcate setae with unequal tynes connected by a web of numerous fine needles; tips of tynes blunted, shaft with transverse rows of barbs ( Fig. 42 G). Thoracic neuropodia of setigers 1–10, with 4–6 rows of uncini of two types: (1) 3–5 rows of large, heavy uncini, each with curved apex surrounded by long sheath and followed by shaft with transverse ridges; sheath sometime frayed, appearing bristled ( Figs. 42 D, 43C–D), (2) a posterior row of narrower crenulated spines ( Fig. 42 E); posterior row of numerous crenulated companion capillary setae accompany uncini; from about setiger 11–12, uncini of posterior thoracic neuropodia mostly replaced by large, dark, spear-like spines ( Figs. 42 B, F, 43E) accompanied by numerous long, crenulated capillaries ( Fig. 43 E). Abdominal neurosetae including 5–6 short capillaries and 1–2 imbedded aciculae ( Fig. 42 C).

Branchiae from setiger 4–5 ( Figs. 42 A, 43B), simple, with lateral and medial cilia, continuing posteriorly ( Fig. 42 C).

Pygidium enlarged, swollen, turned dorsally, with two ventral rounded lobes and two dorsal lobes from which a pair of long anal cirri arise; anus located dorsally between all four lobes ( Fig. 42 H).

Remarks. Phylo felix was thoroughly reviewed, accurately described, and elegantly illustrated by Hartman (1957). The present specimens agree well with her description, although the large collection of specimens permits additional details to be added. In particular, the distribution of thoracic neurosetae is more complex in that there are many more capillaries accompanying the uncini than previously reported.

Phylo felix belongs to a small group of Phylo species having a conspicuous ventral thoracic fringe of papillae and an interramal cirrus in abdominal neuropodia. Hartman (1957) reported the species to have 16–18 thoracic setigers, with the posterior region generally beginning at about setiger 11. Larger specimens were found in the present materials, and there is a suggestion that the development of the posterior modified region is growth dependent. The present collections contain juveniles having 9–12 anterior thoracic setigers and 1–4 posterior modified setigers. Larger adults, on the other hand, have 16–18 anterior thoracic setigers and 6–7 posterior modified setigers. These data suggest that the size of the thoracic region increases with growth of the worm. As the number of thoracic setigers increases, the anterior thoracic segments would have to be derived from posterior modified segments that lose their modified spines and develop fascicles of the anterior uncini. The posterior modified setigers would in turn be derived from anterior abdominal setigers which change form and function. Hartman (1957) did not provide any data to indicate the sizes of the specimens she examined, but I have noted that there is variation in the number of thoracic setigers among similar sized specimens. For example, the syntype of Phylo michaelseni , from the Straits of Magellan, is over 11 cm long and has 19 thoracic setigers of which setigers 1–11 are anterior and 12–19 are posterior and modified. In contrast, specimens from the Nordenskold Expedition, also from the Straits of Magellan, are smaller, less than 10 cm long and yet have 16–20 thoracic setigers, of which the first 10–14 are normal and the last 15–20 are modified.

The type collection of Orbinia (Phylo) minima , described by Hartmann-Schröder & Rosenfeldt (1990) from the Antarctic Peninsula was examined. These specimens have nine anterior and 1–2 posterior thoracic setigers. This diminished number of thoracic setigers was used by these authors as justification for the species. However, the specimens were only 26 mm long, suggesting that they were juveniles. Further, as the O. minima specimens had branchiae from setiger 5 as in larger P. felix specimens and interramal cirri in posterior notopodia, and P. felix is one of only two species of Phylo worldwide to have this arrangement and there are no other morphological differences, O. minima is herein placed into synonymy with P. felix . Five additional specimens from the Antarctic Peninsula examined here (USNM 56452, 56453, and 60645) are also relatively small, with the same 9 + 1–2 thoracic setigers, interramal cirri in abdominal parapodia, and branchiae from setiger 5.

The holotype of Phylo felix heterosetosa from Chile described by Hartmann-Schröder (1965), has been examined and not found to differ from the stem form. The subspecies is therefore synonymized with P. felix in this study.

Distribution. South America: Brazil, Uruguay, Argentina, Patagonia, Southern Chile, Straits of Magellan; Falkland Islands; Antarctic Peninsula and off Elephant Island, Intertidal to 430 m.

Figures

FIGURE 42. Phylo felix Kinberg, 1866. A, Anterior end, left lateral view; B, posterior thoracic parapodium, anterior view; C, abdominal parapodium, anterior view; D, heavy thoracic neuropodial uncinus; E, thin thoracic neuropodial uncinus; F, spearlike neuroseta from posterior thoracic setiger; G, furcate seta; H pygidium. (A, C, G, after Hartman, 1957; A, D – H, originals from LUCE, Sta. M 60, SMNH 154435).

FIGURE 43. Phylo felix Kinberg, 1866. (LUCE, Sta. M 60, SMNH 154435). A, anterior end, dorsolateral view; B, another specimen, right lateral view; C – D, thoracic neuropodial uncini; E, posterior thoracic parapodium, ventral view, with thoracic neuropodial spear; F, posterior thoracic and anterior abdominal segments showing stomach papillae.