Pterocirrus Claparède, 1868

Salazar-Vallejo, Sergio I., 2022, New species of hesionid and phyllodocid polychaetes (Annelida, Errantia) from Clipperton Island, Zoosystema 44 (1), pp. 1-26 : 18-19

Genus Pterocirrus Claparède, 1868

Pterocirrus Claparède, 1868: 558 . — Michaelsen 1892: 103. — de Saint-Joseph 1895: 226. — Ehlers 1904: 17. — McIntosh 1908: 62. — Uschakov 1972: 151. — Pleijel 1991: 240.

TYPE SPECIES. — Eulalia (Pterocirrus) velifera Claparède, 1868 by subsequent designation ( Bergström 1914: 98); junior synonym of Phyllodoce (Eulalia) macroceros Grube, 1860 after Grube (1880: 211).

DIAGNOSIS (modified after Pleijel 1991). — Phyllodocids with prostomium oval to cordate with two lateral antennae, median antenna well developed; eyes usually large, well developed. Nuchal organs not projected posteriorly. Four pairs of tentacular cirri; dorsal cirri cylindrical to medially widened, ventral cirri similar except in segment 2, being larger, foliose. Median segments with dorsal cirri lanceolate to cordate. Supracicular lobes blunt to tapered, sometimes more projected than subacicular lobes. Neurochaetal shafts with scarce distal denticles. Anal cirri tapered. Pharyngeal surface with abundant filiform papillae, rarely globose.

DISTRIBUTION. — The species of Pterocirrus have been described mostly from shallow-water localities from tropical, temperate and polar seas.

REMARKS

Pterocirrus Claparède, 1868 was proposed as a subgenus in Eulalia Savigny, 1822 , and it was regarded as an independent genus by Michaelsen (1892: 103), de Saint-Joseph (1895: 226), and Ehlers (1904: 17). However, Bergström (1914: 99) regarded it as a junior synonym of Sige Malmgren, 1865 . His conclusion was surprising because of three facts. First, Sige lacks winged ventral cirri in segment 2, which were used for naming the subgenus as Pterocirrus . Second, Sige has digitate, markedly projected supracicular lobes, which are not so projected in Pterocirrus . Third, in Sige the pharynx appears smooth, but in Pterocirrus it was characterized as having abundant large, blunt papillae by McIntosh (1908: 62).

As part of his monograph on Northwestern Pacific polychaetes, Uschakov (1972: 151) included a key to phyllodocid genera, reinstated Pterocirrus as an independent genus, and provided a diagnosis and a key for identifying its species. Uschakov’s proposal was followed by Banse (1973), Banse & Hobson (1974), and Fauchald (1977). Pleijel (1991) analysed the phylogeny and proposed a new classification for the Phyllodocidae , including revised diagnosis for all genera.

On the other hand, Pterocirrus resembles Eulalia Savigny, 1822 because in both genera, ventral cirri of segment 2 are wider than the others, although in Eulalia they are not so markedly expanded as in Pterocirrus , and in Eulalia the pharynx has globular papillae, but they are thinner, filiform in Pterocirrus . Further, in Eulalia acicular lobes are blunt, of similar size, whereas in Pterocirrus the supracicular lobe is often more projected than the subacicular one.

KEY TO SPECIES OF PTEROCIRRUS CLAPARÈDE, 1868 (MODIFIED AFTER USHAKOV 1972)

1. Median antenna inserted close to anterior prostomial margin ................................................................. 2

— Median antenna inserted towards prostomial central area, between eyes ............................................... 13

— Median antenna inserted towards posterior prostomial margin; prostomium oval, slightly wider than long ... 20

2(1). Prostomium cordate (widened posteriorly) ............................................................................................. 3

— Prostomium oval, usually longer than wide ............................................................................................. 9

3(2). Eyes oval, markedly pigmented ............................................................................................................... 4

— Without eyes, two large oblique, scarcely pigmented spots; dorsum dark olive green ................................. .......................................................................................... P. slastnikovi ( Annenkova, 1946) Arctic Ocean.

4(3). Dorsum with homogeneous pigmentation .............................................................................................. 5

— Dorsum with heterogeneous pigmentation, transverse brownish bands, segments 4-5 pale, intersegmental areas pale; eyes half as long as prostomium; supracicular lobes more projected than subacicular ones ......... ................................................................................. P. burtoni Pleijel, Aguado & Rouse, 2012 California.

5(4). Prostomium middorsally projected posteriorly; dorsum grayish to pale green;eyes 1/3-¼ as long as prostomium ............................................................................ P. limbatus ( Claparède, 1868) Mediterranean Sea

— Prostomium posterior margin not projected, pigmented; dorsum brownish ............................................ 6

6(5). Palps and lateral antennae of similar length (palps terminal) ................................................................... 7

— Palps half as long as lateral antennae (palps displaced ventrally); supracicular lobes more projected than subacicular ones ...................................... P. macroceros ( Grube, 1860) Mediterranean, Northeastern Atlantic.

7(6). Segments dorsally smooth, without papillae ............................................................................................ 8

— Segments with a dorsal row of minute papillae; acicular lobes parallel; about 26 neurochaetae per bundle ... ........................................................................ P. macroceros orientalis (Imajima & Hartman, 1964) Japan.

8(7). Median antenna as long as lateral ones; dorsal cirri tapered, without subdistal constriction; acicular lobes barely divergent; 12-22 neurochaetae per bundle (6.5-17.0 mm long) ......... P. bouchardi n. sp. Clipperton Island.

— Median antenna shorter than lateral ones; dorsal cirri with a subdistal constriction; acicular lobes divergent; about 20 neurochaetae per bundle (35 mm long) ................. P. montereyensis ( Hartman, 1936) California.

9(2). Eyes large, oval ...................................................................................................................................... 10

— Eyes minute; dorsal cirri lanceolate, slightly longer than wide .................................................................... .................................................................................... P. parvoseta ( Banse & Hobson, 1968) Washington.

10(9). Median antenna longer than lateral ones; eyes half as long as prostomium ................................................. ................................................................................................ P. foliosus ( Treadwell, 1924) Caribbean Sea.

— Median antenna as long as lateral ones .................................................................................................. 11

— Median antenna shorter than lateral ones; dorsum pale purple ................................................................... .................................................................................. P. marginatus ( Claparède, 1868) Mediterranean Sea.

11(10).Dorsal cirri cordate ............................................................................................................................... 12

— Dorsal cirri lanceolate, about twice longer than wide; dorsum dark greenish-brown with pale intersegmental bands ......................................................................................... P. ceylonicus Michaelsen, 1892 Sri-Lanka.

12(11).Prostomium as wide as long, or wider than long; dorsal cirri 1/3 longer than wide; dorsum with broad longitudinal band ............................ P. foliosus ( Treadwell, 1924) sensu Eibye-Jacobsen 1992 Grand Caribbean.

— Prostomium longer than wide; dorsal cirri as long as wide; dorsum homogeneously yellowish brown ........ .......................................................................................................... P. nidarosiensis Pleijel, 1987 Norway.

13(1). Prostomium cordate (wider posteriorly) ................................................................................................ 14

— Prostomium oval ................................................................................................................................... 19

14(13).Median antenna shorter than prostomial width .................................................................................... 15

— Median antenna as long as prostomial width ........................................................................................ 18

15(14).Eyes small, 1/10 as long as prostomial length; dorsal cirri twice longer than wide, lanceolate, tapered; neurochaetal blades 8× longer than wide .............................. P. magalaensis minuta ( Averincev, 1972) Antarctica.

— Eyes large, 1/3 to ¼ prostomial length .................................................................................................... 16

16(15).Median antenna long, 7× longer than wide; eyes 1/3 as long as prostomial length ........................................ .............................................................................. P. microcephalus ( Claparède, 1870) Mediterranean Sea.

— Median antenna short, 3-4× longer than wide; eyes ¼ as long as prostomial length .............................. 17

17(16).Neurochaetal blades 12× longer than wide; dorsal cirri 2.5× longer than wide; median antenna 4× longer than wide ..................................................................................... P. brevicirris Ehlers, 1904 New Zealand.

— Neurochaetal blades up to 6× longer than wide; dorsal cirri twice longer than wide; median antenna 3× longer than wide ................................................................... P. magalaensis (Kinberg, 1865) Magellan’s Strait, Chile.

18(14).Eyes small, 1/7 as long as prostomial length; dorsal cirri cordate, slightly longer than wide .......................... .............................................................................................. P. hunteri ( Benham, 1921) Antarctic Ocean.

— Eyes large, 1/3 as long as prostomial length; dorsal cirri lanceolate, twice longer than wide .......................... ............................................................................................ P. macleani ( Benham, 1921) Antarctic Ocean.

19(13).Eyes small, 1/7 as long as prostomial width; dorsal cirri lanceolate, slightly longer than wide ....................... ......................................................................................... P. giribeti Leiva & Taboada in Leiva et al. 2018.

— Without eyes; dorsal cirri lanceolate, twice longer than wide ..................................................................... ................................................................................................ P. remus Böggemann, 2009 Western Africa.

20(1). Eyes large, ¼ as long as prostomial length; dorsal cirri cordate, slightly longer than wide ........................... ............................................................................................................. P. notoensis ( Imajima, 1967) Japan.

— Without eyes (larger dark spots displaced anteriorly); dorsal cirri lanceolate, 4× longer than wide .............. ..................................................................... P. imajimai Ushakov, 1972 Japan, California, 3260-5460 m.