Euarche tubifex Ehlers 1887

Euarche tubifex Ehlers, 1887

Euarche tubifex Ehlers, 1887:54, pl. 2: figs. 1–7, pl. 13: fig. 1.

Eupanthalis kinbergi.—Fauvel, 1914b:80; 1923:100, fig. 38i–q; 1936:14.—Monro, 1928:568.—Hartman, 1938a:5; 1974 [1975]:209.—Paris, 1954:501, figs. 8, 9b–d.—Fauvel and Rullier, 1959:152, figs. 1–3.—Rullier, 1965b:17.—Day, 1973:9.—Intes and Le Loeuff, 1975:283.—Rullier and Amoureux, 1979:153.—Campoy, 1982:83. [Not Eupanthalis kinbergi McIntosh, 1876.]

Eupanthalis tubifex.—Augener, 1918:125, pl. 2: fig. 20.—Monro, 1930:69.—Hartman, 1951:20; 1959:110.—Strelzov, 1972:302 [part].—Wolf, 1986:83.

Eupanthalis perlae Fauchald, 1977a:7, fig. 2a–f. [New synonym.]

Eupanthalis sp.—Wolf, 1984:10, figs. 5, 6a–s.

Eupanthalis rudipalpa Amaral and Nonato, 1984:14, figs. 1–11. [New synonym.]

MATERIAL EXAMINED.—CARIBBEAN. 11°34′N, 69°02′W, 223 m, Albatross sta 2124. 18 Feb 1884, 6 specimens (USNM 1683).

FLORIDA. 28°51′N, 89°01′W, 216 m, Blake sta 49, 1877–1878, holotype of E. tubifex (MCZ 659). 29°28′N, 80°57′W, R/V Pierce sta 7B, 27 Nov 1977, 20 m, 1 specimen (USNM 59173).

SOUTH CAROLINA. 32°23′N, 80°09′W, R/V Pierce sta 3B, 17 Feb 1977, 13 m, 1 specimen (USNM 59172); 32°13′N, 79°52′W, sta 3C, 23 Aug 1977, 22 m, 1 specimen (USNM 59174).

NORTH CAROLINA. Off Beaufort, 450 m, J.H. Day, collector, 1 specimen (USNM 50692, as Eupanthalis kinbergi by Day, 1973). Off Cape Hatteras, M. Cerame-Vivas, collector: 35°14′N, 75°06′W, 10 Sep 1962, 73 m, 1 specimen (USNM 50693); 34°56′N, 75°26′W, 19 Dec 1962, 84 m, 1 specimen (USNM 50694); 35°16′N, 75°03′W, 4 Mar 1962, 55 m, 1 specimen (USNM 50695).

GULF OF MEXICO. 25°N, 84°W, 128 m, M.L. Jones, collector, 14 Jul 1965, 1 specimen (USNM 50712). R/V Alaminos cruises, W.E. and L.H. Pequegnat, collectors: cr 64A1. sta 13C,D, Jun 1964, 27°52′N, 94°56′W, 121–181 m, 21 specimens (USNM 71450); cr 69A, sta 11, lots 56, 60, 76, Aug 1969, 19°00′ to 21°16′N, 95°31′ to 96°57′W, 183–201 m, 18 specimens (USNM 71451–71453); cr 71A, sta 7, lots 17 and 32, sta 8, lot 20, Jul, Aug 1971, 23°52′ to 27°55′N, 92°48′ to 97°16′W, 134–204 m, 27 specimens (USNM 71454–71456). South Texas Outer Continental Shelf Study (STOCS): sta I-6, 27°39′N, 96°12′W, 100 m, silty clay, spring 1976, 1 specimen (USNM86164); sta III-4, 26°58′N, 97°01′W, 27 m, clayey sand, winter 1976, juvenile (USNM 86862); sta IV-4, 26°10′N, 97°08′W, 15 m, sand, fall 1976, Dec 1980, 3 specimens (USNM 86860, 86861, 86863). Mississippi-Alabama-Florida Outer Continental Shelf Study (MAFLA), sta 2427, 28°49′59″N, 85°37′01″W, 175 m, clayey, sandy silt, Sep 1977, 1 specimen (USNM 55798) (as Eupanthalis sp. A, by Wolf, 1984). Mississippi Sound, Army Corp. of Engineers, sta 589, 30°09′16″N, 88°11′08″W, 15.2 m, sand/silty sand, 30 Oct 1980, adult and juvenile (USNM 75624, 75625); sta 477, 30°09′53″N, 88°27′38″W, 23.8 m, sand, 2 Nov 1980, 1 specimen (USNM 75626).

PANAMA (Pacific). San José Island, Perlas Island, 46 m, mud and shells, Mortensen, collector holotype of Eupanthalis perlae (UZMC; as E. kinbergi by Monro, 1928).

WEST AFRICA. Belgian Congo, Gazelle Expedition 5 specimens (ZMB 882; USNM 51979, as Eupanthalis tubifex by Augener, 1918). Off St. Paul de Loanda, Angola, 08°40′15″S, 13°13′45″E, 64–65 m, gray mud, Discovery sta 274, 4 Aug 1927, 1 specimen (BMNH 1930.10.8.1778, as E. tubifex by Monro, 1930).

NORTHWEST AFRICA. Off Morocco, 33°56′N, 07°25′W, 125 m, mud, Vanneau sta 15, 20 Jul 1923, J. Liouville and Ph. Dollfus, collectors, 1 specimen (BMNH 1928.4.26.354, as E. kinbergi by Fauvel, 1936).

ARABIAN SEA. 25°35′N, 57°09′E, 256 m, sta 254B, 30 Nov 1963, 2 specimens (AHF, as E. kinbergi by Hartman, 1974 [1975]).

TYPE MATERIAL.—The holotype of Euarche tubifex Ehlers (MCZ), from off Florida in 216 meters, is in poor condition, having been dry. Part of the thick leathery tube remains. According to Ehlers, the worm was 130+ mm long, 5 mm in greatest width in the anterior part, with 160+ segments, and the posterior end broken off.

The holotype of Eupanthalis perlae Fauchald (UZMC), from the Perals Islands on the Pacific side of the Isthmus of Panama, is 19+ mm long, 7 mm wide with setae, with 44+ segments; it is a female massed with large yolky eggs in the body cavity.

DESCRIPTION.—Largest complete specimen examined from off West Africa (BMNH 1930.10.8.1778) 310 mm long, 11 mm wide with setae, 176 segments ( with large yolky eggs). Complete specimen from Arabian Sea (AHF) 120 mm long, 5 mm wide with setae, with 177 segments ( with large yolky eggs). Widths of other incomplete specimens 5 to 16 mm with setae.

Elytra delicate, transparent, first pair largest, elongate-oval, following pairs smaller, rounded, leaving middorsum uncovered (Figures 1B, E–G, 5A,G; Ehlers, 1887, pl. 12: fig. 1).

Prostomium oval, with 2 pairs of eyes subequal or anterior pair larger than posterior pair; median occipital antenna on small ceratophore on posterior part of prostomium, with small lateral papilla, with style extending slightly beyond prostomium; lateral antennae on short ceratophores on anterior border of prostomium, with styles similar to median antenna; palps stout, long, tapered with longitudinal rows of short papillae on distal two-thirds (Figures 1A–C, 4A; Ehlers, 1887, pl. 12: fig. 1; Fauchald 1977a, fig. 2b).

Tentacular segment distinct dorsally, with median nuchal lobe forming attachment for ceratophore of occipital antenna; tentaculophores lateral to prostomium and palps, usually with few rows of papillae on inner dorsal part, with or without few capillary setae; dorsal and ventral tentacular cirri longer and stouter than antennae, subequal in length or ventral ones slightly longer than dorsal ones (Figures 1A–C, 4A).

Second or buccal segment with first pair of elytrophores and biramous parapodia; notopodium conical, on anterodorsal side of larger neuropodium, with bundle of long, finely spinous, capillary notosetae extending far beyond neurosetae; neuropodium with conical or slightly bilobed presetal acicular lobe and shorter rounded postsetal lobe; row of short neurosetae all spinous, with capillary tips, middle ones stouter; ventral buccal cirri similar to tentacular cirri, longer than following ventral cirri (Figures 2A–D, 4A,B).

Large eversible muscular pharynx with circle of 11–15 (usually 13) pairs of papillae, median dorsal one slightly longer than others, on enlarged base; median ventral one 2- to 4-lobed, on enlarged base; 2 pairs of stout dark-colored hooked jaws each with 4–6 lateral teeth (Figure 1D; Ehlers, 1887, pl. 12: figs. 1–3).

Dorsal cirri of segment 3 with short cylindrical cirrophores on dorsoposterior sides of notopodia; style tapering, extending beyond neurosetae, longer than following dorsal cirri (Figures 2E, 4C). Parapodia of segments 3 to 8 gradually changing; notosetae becoming fewer and shorter (Figures 2E,G, 4C,G,H); upper neurosetae few, spinous, tapering to fine tips (Figures 2B,H, 41); middle neurosetae stout, acicular, with blunt tips and few hairs, with or without aristae (Figures 2F, 4E); lower neurosetae slender, slightly curved, spinous, with larger spines basally and close-set spines distally, tapering to slender tips (Figures 2D, 4F).

Beginning with segment 9, notopodia forming rounded flattened lobes on anterodorsal sides of neuropodia, with development of internal spinning glands, with spinning fibers emerging through slit on inner side of notopodium (Figures 2I, 3B, 5A,G). Neuropodia with slightly bilobed anterior acicular lobes and diagonally truncate postsetal lobes, with only slightly developed lower bracts. Lower neurosetae similar to more anterior ones (Figures 3E, 5D,J; Ehlers, 1887, pl. 12: fig. 6; Fauchald, 1977a, fig. 2d). Middle neurosetae stouter, acicular, tips slightly hooked with subdistal hairs, with or without aristae (Figures 2K, 3D, 5C,I; Ehlers, 1887, pl. 12: fig. 7; Fauchald, 1977a, fig. 2e). Upper neurosetae emerging from small bract on upper anterior side of neuropodium (Figure 2I, 3B), of 2 types: (a) longer, tapering to slender tips, with continuous row of hairs perpendicular to stem; (b) shorter, more slender, tapering to sharp tips, with widely spaced groups of spines (Figures 2J, 3C, 5B,H; Fauchald, 1977a, fig. 2a,c,f). Dorsal cirri shorter, inflated basally; ventral cirri short, subulate (Figures 3A, 5E,F; Ehlers, 1887, pl. 12: fig. 5).

Pygidium small, between small posterior parapodia. No distinct branchial vesicles except for thin-walled, somewhat inflated areas medial to ventral cirri.

TUBE.—The tube was described and figured by Ehlers (1887:56, pl. 13: fig. 1). It is 280 mm long, about twice as long as the worm, neatly annulated on its anterior narrower end (7 mm wide), where it forms black muddy tubes of unequal width pushed into one another, then becomes wider (16 mm) and thicker on its posterior closed end. In cross-section the thick muddy wall, of weak leathery consistency, has a stratified structure with a smooth inner surface. Part of a tube is present with a specimen from North Carolina (USNM 50693). It is thick, felt-like, and appears indistinctly annulated.

BIOLOGY.—Hartman (1951:20) reported specimens, collected in November, from the Gulf of Mexico off Texas in 139 meters, as having the body cavities filled with sperm bundles or ova abruptly after segments 30–34. A large female from the Belgian Congo (USNM 51979) has large yolky eggs in the body cavity from about segment 47.

COMMENSALS.—Rullier (1965b:17) and Intes and Le Loeuff (1975:283) reported small bivalve mollusks of the family Montacutidae between the parapodia of specimens of E. tubifex (as Eupanthalis kinbergi) from Dahomey and the Ivory Coast, West Africa.

DISTRIBUTION.—Caribbean, Northwest Atlantic from Florida to North Carolina, Gulf of Mexico, Panama (Pacific), Southwest Atlantic to South Brazil, Northeast Atlantic from West to Northwest Africa, Mediterranean, Arabian Sea. In 13 to 450 meters.