Nereiphylla etiennei, Salazar-Vallejo, 2022

Salazar-Vallejo, Sergio I., 2022, New species of hesionid and phyllodocid polychaetes (Annelida, Errantia) from Clipperton Island, Zoosystema 44 (1), pp. 1-26 : 14-18

Nereiphylla etiennei n. sp.

( Fig. 4 )

urn:lsid:zoobank.org:act:3237FFEC-D57E-4F6D-8855-482224D3A114

TYPE MATERIAL. — Holotype. Clipperton Island • 1 specimen; Sta. 16; 10°19.22’N, 109°13.38’W; cryptic organisms among rocks; hand collecting; 55 m; 19.I.2005; J.-M. Bouchard, L. Albenga, L. Dugrais, leg.; MNHN-IA-TYPE2044.

Paratypes. Clipperton Island • 2 specimens; Sta. 16; 10°19.22’N, 109°13.38’W; stone cryptic organisms; hand collecting; 55 m; 19.I.2005; J.-M. Bouchard, L. Albenga, L. Dugrais leg.; MNHN- IA-TYPE2045 (without posterior region; pharynx partially or fully everted; dorsal cirri paler anteriorly, darker in median and posterior chaetigers; dark brown pigmentation in globular glands along dorsum, especially in parapodial regions forming an ill-defined band, sometimes reduced to two lateral spots close to parapodia, and variably abundant in parapodia; fragments 4.7-5.2 mm long, 0.25-0.30 mm wide, 65- 6 chaetigers) • 1 specimen; Sta. 15 (no coordinates); chaetopterid tube mass and small stones; 37 m; 19.I.2005; J.-M. Bouchard, L. Albenga, L. Dugrais, leg.; ECOSUR 277 (complete, broken into three pieces; pharynx partially everted; anterior fragment twisted, prostomium directed backwards; anterior fragment 2.7 mm long, 0.2 mm wide, 38 chaetigers; longest tentacular cirri reach chaetiger 5-6; anterior dorsal cirri pale, posterior ones darker; posterior fragment 0.8 mm long, 0.15 mm wide, 18 chaetigers).

DIAGNOSIS. — Nereiphylla with prostomium rectangular, longer than wide; lateral antennae half as long as prostomial width; eyes 1/6-1/7 prostomial width; longest tentacular cirri reach chaetiger 5; dorsal cirri cordate, blunt, longer than wide; ventral cirri oval, blunt.

ETYMOLOGY. — The specific epithet is after Dr. Jean-Luis Étienne, a famous French explorer and writer, as a modest homage after his efforts for organizing the Clipperton 2004-2005 Expedition. It meant a lot of work and coordination to support about 30 researchers doing field work for 5 months on the island. He also wrote the chapter on the history of the island ( Étienne 2009). The specific epithet is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

DISTRIBUTION. — Only known from Clipperton Island, in rocky bottoms, 37-55 m depth.

DESCRIPTION

Body

Holotype (MNHN-IA-TYPE2044) an anterior fragment, almost cylindrical, brownish, with most cirri on site, anterior cirri paler ( Fig. 4A ); body truncate anteriorly, of similar width throughout fragment, 2.7 mm long, 0.3 mm wide, 33 chaetigers.

Prostomium rectangular, slightly longer than wide ( Fig. 4A ). Lateral antennae and palps oblong tapered, of similar length, half as long as prostomial width ( Fig. 3B ); without median antenna. Eyes dark brown, about 1/7 as long as prostomial width. Posterior prostomial notch not seen, a paler area visible, but not depressed. Segment 1 completely reduced dorsally. Nuchal organs not seen. Pharynx

Pharynx partially exposed in paratypes ( Fig. 4B ), brownish, as long as first 6 segments; surface completely covered by globular papillae, in alternating rows, each papilla slightly longer than wide; 8-9 larger papillae in aperture.

Tentacular cirri

Tentacular cirri all cirriform, tapered; cirri of segment 1 reaching segment 4 (chaetiger 2); dorsal cirri of segment 2 longest, reaching segments 7-8 (chaetiger 5-6), ventral cirri of segment 2 reaching segment 4 (chaetiger 2); dorsal cirri of segment 3 reaching segment 7 (chaetiger 5). Segment 3 with neuropodial lobe and chaetae.

Parapodia and chaetae

Parapodia with dorsal cirri cordate, longer than wide, with better defined tips in anterior chaetigers, blunt in median and posterior ones; dorsal cirri paler in anterior chaetigers, darker in median and posterior chaetigers ( Fig. 4C, D ). Parapodial glands globular, brownish to dark brown, often projected from body wall giving cirri a rugose outline. Neuropodial lobe conical, acicular lobes not defined. Neurochaetae 7-8 compound spinigers per bundle; handle prismatic, almost smooth, blades delicate, 8-9× longer than wide, finely denticulate. Ventral cirri oval, blunt, with less pigmented glands than dorsal cirri, barely longer than neurochaetal lobe. Posterior parapodia in one paratype (ECOSUR 277) with abundant spermatids in coelom.

Posterior region

Visible in one paratype ( Fig. 4D ) tapered into a blunt cone; pygidium with anus terminal, anal cirri 2-3× longer than dorsal cirri of previous chaetigers, lanceolate, with long tips and abundant brownish globular glands.

VARIATION

Pigmentation varies, with the anterior region often paler than median and posterior ones. Globular pigmented glands vary in abundance along body; dorsum often with a transverse band with abundant to sparse glands, and in paler segments often one pair of pigmented glands are visible one on each side, close to parapodial bases. The prostomial shape is not modified after pharynx eversion. Dorsal cirri are longer and with tips better defined along anterior chaetigers, but in median and posterior chaetigers they become shorter and with tips less defined. One of the paratypes (ECOSUR) has spermatids in parapodial coelom and although the other specimens were not dissected, they are regarded as mature organisms, not juveniles despite their small size.

REMARKS

Nereiphylla etiennei n. sp. resembles what Gardiner (1976: 113, Fig. 7h-k) recorded from the Northwestern Atlantic as N. castanea ( von Marenzeller, 1879) . These two species have prostomium longer than wide, eyes 1/6-1/7 as long as prostomial width, longest tentacular cirri reaching chaetiger 5, dorsal cirri cordate, longer than wide, and ventral cirri oval, blunt. These species differ especially because in N. etiennei n. sp. the prostomium is rectangular, lateral antennae are half as long as prostomial width, and ventral cirri are barely longer than neurochaetal lobe, whereas in Gardiner’s specimens the prostomium is oval, lateral antennae are 1/3 as long as prostomial width, and ventral cirri are longer than neurochaetal lobes.

On the other hand, N. castanea has been recorded from many different localities throughout the world. Some of the records include descriptions and illustrations such that they were regarded as different from the typical form in the key above, as redescribed by Izuka (1912: 199, Pl. 21, Fig. 3 ). These differences deserve a further study to clarify their relevance and if confirmed, they should be regarded as distinct species. This, however, is beyond the objective of this contribution.

Figures

FIG. 4. — Nereiphylla etiennei n. sp.: A, holotype (MNHN-IA-TYPE2044), anterior region, dorsal view; B, paratype (MNHN-IA-TYPE2045), anterior region, right lateral view; C, paratype (ECOSUR 277), posterior chaetiger, posterior view; D, same, posterior region, dorsal view. Scale bars: A, B, D, 0.1 mm; C, 30 µm.

FIG. 3. — Anaitides albengai n. sp., paratypes (ECOSUR 276, Sta.26): A, shorter paratype, anterior end,oblique frontal view,pharynx partially exposed by fracture of body wall; B, same,chaetiger 33, right parapodium,posterior view (after Shirlastain-A,asterisk indicates area to be enlarged);C, same,close-up of ciliary band; D, same, chaetiger 73, right parapodium, posterior view (asterisk indicates area to be enlarged); E, same, close-up of ciliary band; F, longer paratype, anterior end and pharynx, left lateral view (left antenna lost; asterisk indicates nuchal organ). Scale bars: A, B, 0.3 mm; C, D, 0.1 mm; E, 20 µm; F, 0.2 mm.