Ephesiopsis guayanae Hartman & Fauchald, 1971

Capa, Maria, Osborn, Karen J. & Bakken, Torkild, 2016, Sphaerodoridae (Annelida) of the deep Northwestern Atlantic, including remarkable new species of Euritmia and Sphaerephesia, ZooKeys 615, pp. 1-32 : 4-6

Taxon classification Animalia Phyllodocida Sphaerodoridae

Ephesiopsis guayanae Hartman & Fauchald, 1971 Figs 1, 2

Sphaerodorum sp. C.- Hartman 1965: 96, pl. 14, Figs A–B.

Ephesiopsis guayanae Hartman & Fauchald, 1971: 68-69, Pl 33, figs A–G.

Material examined.

Holotype: LACM- AHF POLY TYPE 942, off Dutch Guayana Surinam, 07°52'N, 54°31.5'W, 520-550 m, coll. Woods Hole Oceanographic Institution, 25 Apr 1963. Paratype: same collection information LACM- AHF POLY TYPE 943 (1 ind.).

Additional material.

USNM 1001772 (2 ind.), Georges Bank, 40°57.21'N, 066°13.68'W, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 25 Jul 1986; USNM 1001773 (1 ind.) off New Jersey, 38°35.98'N, 072°52.86'W, 2195 m, coll. MMS Collections;

USNM 1001777 (1 ind.), off New Jersey, United States, 2150 m, 1 Dec 1984, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR; USNM 1001713 (1 ind.), off Cape Lookout, North Carolina, 34°11.16'N, 75°38.98'W, 2006 m, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 14 Jul 1984; USNM 1001780 (1 ind.), off Delmarva, 37°51.58'N, 73°19.914'W, 2100 m, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 30 Nov 1984; USNM 1001781 (1 ind.), off New Jersey, 38°29.28'N, 72°42.11'W, 2507 m, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 4 Dec 1984; USNM 1001782 (1 ind.), off New Jersey, 38°29.23'N, 72°42.19'W, 2505 m, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 18 May 1985; USNM 1001783 (1 ind.), off New Jersey, 38°29.23'N, 72°42.19'W, 2505 m, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 18 May 1985; USNM 1001789 (1 ind.), Baltimore Canyon, Maryland, 37°53.76'N, 73°44.76'W, 1499 m, coll. MMS Collections, Atlantic Slope and Rise Program, ASLAR, 15 Nov 1985.

Comparative material.

Ephesiopsis shivae , holotype MZSP883 24°07.637'S 45°51.895'W, 09 Jan 1998, Sta. 6661, 147 m, Santos/ São Paulo to Ilha Grande Bay/Rio de Janeiro; paratypes MZSP1031 (2 ind.), 24°07.637'S, 45°51.895'W, 09 Jan 1998, Sta. 6661, 147 m, Santos/ São Paulo to Ilha Grande Bay/Rio de Janeiro.

Diagnosis.

Palps and lateral antennae digitiform, median antenna shorter. Tentacular cirri ellipsoid. Parapodia with 4-6 parapodial papillae; compound chaetae with blades 1.5-2.5 times as long as maximum width on mid-body chaetigers, simple chaetae wider and with angular silhouette; hooks present on first chaetiger.

Re-description.

Measurements and general morphology. Holotype 2.2 mm long, 0.2 mm wide, with 26 chaetigers, divided in two. Body elongated, sub-quadrangular in section, with slightly convex dorsum. Anterior end bluntly rounded, slightly narrowing along posterior segments. Segmentation inconspicuous, tegument with transverse wrinkles. Preserved specimen lacking pigmentation.

Head. Prostomium with five short appendages, including a pair of digitiform palps in ventral-most position, a pair of lateral antennae, similar in shape and size to palps, and a median antenna, shorter (one third) and thinner than lateral antennae (Fig. 2A, B). A pair of tentacular cirri shorter than lateral antennae and palps. A few rounded (about six) small papillae confined by head appendages.

Tubercles. First chaetiger with two dorsal macrotubercles; microtubercles absent (Fig. 2B). Following chaetigers each with two dorsal macrotubercles arranged in two dorso-lateral longitudinal rows, and two microtubercles forming two longitudinal rows between the macrotubercles (Fig. 2 B–D, F). Macrotubercles sessile and spherical each provided with a digitiform terminal papilla (Fig. 2 B–D, F); with groups of pores around terminal papilla. All macrotubercles similar in shape and size. Microtubercles with digitiform terminal papilla generally longer than collar (Fig. 2C). Spherical or ellipsoid papillae over dorsum, arranged in 3-4 transversal rows per chaetiger, with around 15-20 papillae on each mid-body chaetigers. Ventral surface with spherical papillae, arranged in four more or less regular transversal rows, with about 20 per segment, in mid-body; numbers decreasing towards posterior end (Fig. 2F). Body epithelium with ellipsoid granules.

Parapodia. Parapodia sub-conical, increasing in size towards chaetiger 3 (Fig. 2B), around 1-3 times longer than wide (Fig. 2 C–E). Acicular lobe projecting distally anterior to chaetae, resembling other parapodial papillae or slightly longer (Fig. 2E). Ventral cirri digitiform projecting as long as acicular lobe on anterior segments or shorter in mid-body and posterior ones (Fig. 2 C–E). Mid-body parapodia with 4-5 ellipsoid to digitiform papillae, all similar in size, in addition to the acicular lobe: 2-3 anterior, 1-2 posterior-ventral (Fig. 2 C–E).

Chaetae. First chaetiger with two pairs of hooks, one pair on each parapodia together with elongate simple chaetae. One compound and 2-4 simple chaetae in all chaetigers, arranged in a curved transverse row around acicular lobe (Figs 1A, B, 2 G–L). First and second chaetigers with slightly serrated long blades, 4-5 times longer than wide. Chaetae from chaetiger 3 with shafts widened sub-distally, a larger distal tooth and fine spinulation; blades twice as long as wide (Fig. 2 G–L).

Pygidium. Pygidium terminal, with one mid-ventral digitiform anal cirrus and a pair of dorsal anal cirri, similar in shape but slightly smaller than macrotubercles (Fig. 2F).

Internal features. A pair of eyes anterior to first chaetiger.

Reproductive features. Copulatory organs or eggs not seen in holotype. Paratype with eggs in coelomic cavity.

Variation.

The paratype, an incomplete gravid female, is larger than holotype, 3 mm long and 0.25 wide, with 44 chaetigers. The specimen from New Jersey is 2 mm long and 0.25 wide. The number and morphology of chaetae showed variation among the material examined. The holotype possessed two pair of hooks on first chaetiger, absent or not seen in the paratype while the specimen from New Jersey had one pair (Fig. 2B). Additionally, an extra set of thin and simple chaetae, resembling those present in rest of chaetigers were observed only on the holotype. Following chaetigers had fascicles with 3-5 chaetae, one of them clearly compound in the holotype, two in the paratype and up to three in the specimen from New Jersey. Chaetae appearing compound under the light microscope (Fig. 1B) did not clearly seem so under the electron microscope (Fig. 2G, I, J), but at least a faint edge between the shaft and the blade could be noticed. The simple chaetae, probably a result of the fusion of shaft and the blade, show in some cases a different outline, with an angular edge, and a less curved tip (Fig. 2H, L).

Remarks.

The most remarkable attribute of this species is the presence of simple chaetae, in all parapodia, that are flat and sub-distally widened and have an angular contour. This differs from other members of the long bodied sphaerodorids ( Ephesiella and Sphaerodorum ), where chaetae, simple or compound respectively, present more rounded edges. In this respect, the holotype and paratypes of Ephesiella guayanae show some morphological differences, which, if considered as part of the intraspecific variation, may open a discussion of the legitimacy for the genus. These special, simple, sub-distally widened and flat chaetae were not conspicuous in the paratype. The apparently simple chaetae present in both holo- and paratype do not differ much from those pseudocompound chaetae present in other Ephesiella (e.g. Ephesiella brevicapitis Moore, 1909). With so little material in hand, only two types, it is difficult to conclude on the status of the genus and the identity of the paratype. The species seems not to have been found again, until now.

The chaetae of the specimens collected from sediments of deep New Jersey waters resemble those observed in the paratype of Ephesiella guayanae . In every parapodium a group of simple chaetae can be observed, they are not so wide and angular as those present in the holotype, but still they appear to be simple chaetae. Examination of these specimens under SEM revealed a faint oblique mark in the position where an articulation between shaft and blade is expected, and some chaetae seem to be bent at this point. Together these observations suggest that they may be pseudocompound chaetae (Fig. 2 G–L). This cannot be addressed in the type material, which needs to be left intact.

Type locality.

Surinam, Dutch Guayana, 520-550 m.

Distribution.

From Dutch Guayana to New Jersey, 520-2507 m.