Anaitides albengai, 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 : 11-14

Anaitides albengai n. sp.

( Figs 2 ; 3 )

urn:lsid:zoobank.org:act:180C9688-A448-41E1-9406-31E0EF586CA2

TYPE MATERIAL. — Holotype. Clipperton Island • 1 specimen; Sta. 17; 10°19.22’N, 109°13.39’W; epifaunal organisms; hand collecting: 23 m; 20.I.2005; J.-M. Bouchard, L. Albenga & L. Dugrais, leg.; MNHN-IA-TYPE2041.

Paratypes. Clipperton Island • 2 specimens; Sta. 15 (no coordinates); chaetopterid tube mass and small stones; 37 m; 19.I.2005; J.-M. Bouchard, L. Albenga & L. Dugrais, leg.; ECOSUR 275 (small, dorsal cirri remaining in many parapodia; body 4.0- 11.5 mm long, 0.2-0.5 mm wide, 27-79 chaetigers; largest one with pharynx partially exposed; longest tentacular cirri reaching chaetigers 2-6; anal cirri as long as last 2-3 chaetigers; pharynx basal dorsal and ventral surfaces smooth) • 1 specimen; Sta. 23; 10°17.50’N, 109°13.55’W; anchoring point of Rara Avis ; night dive; coral rubble, platform margin; 18 m; 22.I.2005; S. Hourdez & K.-L. Kaiser, leg.; MNHN-IA-TYPE2042 (complete; no pigmentation left; pharynx papillae and parapodial features fit the original description; body 28 mm long, 0.8 mm wide, 156 chaetigers; longest tentacular cirri reach chaetiger 8; anal cirri as long as last 2 chaetigers) • 1 specimen; Sta. 24; 10°17.93’N, 109°14.00’W; coral rubble; night dive; 23 m; 22.I.2005; J.-M. Bouchard, L. Albenga & L. Dugrais, leg.; MNHN- IA-TYPE2043 (small specimen, pale; body 14 mm long, 0.5 mm wide, 90 chaetigers; pharynx basal region with 5 left rows and 12 irregular ones on the right side; ventral and dorsal surfaces smooth; longest tentacular cirri reach chaetiger 10; anal cirri as long as last 3 chaetigers) • 2 specimens; Sta. 26; 10°19.34’N, 109°13.40’W; base of coral mound; 54 m; 23.I.2005; J.-M. Bouchard & L. Dugrais, leg.; ECOSUR 276 (both without posterior end; larger one with about half as many segments as the smaller one; body 22-30 mm long, 1.5-2.0 mm wide, 84-185 chaetigers; longest tentacular cirri reach chaetiger 10; pharynx basal area with 6 rows on the left, and 5 ones on the right; middorsal pharynx surface with 4 papillae in an irregular line; midventral surface smooth; aperture with 16 marginal papillae) .

ADDITIONAL MATERIAL. — Clipperton Island • 2 specimens; Sta. 18; 10°19.22’N, 109°13.38’W; rocks; suction pump, sediment under rocks; 55 m; 20.I.2005; J.-M. Bouchard, L. Albenga, L. Dugrais, leg. ECOSUR (smallest complete, pharynx not exposed; body pale, 28-38 mm long, 0.8-1.8 mm wide, 190-203 chaetigers) • 1 specimen; Sta. 26; 10°19.34’N, 109°13.40’W; base of coral mound; 54 m; 23.I.2005; J.-M. Bouchard, L. Dugrais, leg.; MNHN (complete, dried-out, broken into two pieces, posterior dorsal cirri with small, brown spots; larger section with most of body and few far, posterior chaetigers; body 20 (+8) mm long, 2.5 mm wide, pharynx fully everted 2.5 mm long) • 2 specimens; Sta. 36; 10°17.49’N, 109°13.56’W; anchoring of Rara Avis ; 54 m; 27.I.2005; S. Hourdez, K.-L. Kaiser, J.-M. Bompar, leg.; MNHN (preserved in ethanol; soft, delicate, apparently dead before being fixed) .

DIAGNOSIS. — Anaitides with prostomium as long as wide; eyes ¼ as long as prostomial width; pharynx basal region with 8-9 large, foliose papillae per row; dorsal cirri lanceolate, slightly longer than wide; ventral cirri pointed, longer than neurochaetal lobes.

ETYMOLOGY. — The specific epithet is to honor Laurent Albenga, who participated in the collecting team, and collected the holotype used for the description. The specific epithet is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

DISTRIBUTION. — Only known from Clipperton Island, in rocks and corals, 18-54 m depth.

DESCRIPTION

Body

Holotype (MNHN-IA-TYPE2041) complete mature female, many dorsal cirri distorted or lost, pharynx completely everted ( Fig. 2A ). Body pigmentation almost completely faded out, with some dark pigment along dorsum forming a longitudinal, irregular band, and in some anterior dorsal cirri; body 74 mm long, 2.5 mm wide, 258 chaetigers.

Anterior end

Prostomium cordate, slightly distorted by pharynx eversion ( Fig. 2B ), about as long as wide, slightly bent ventrally, with a slight anterior projection. Palps and antennae oblong, tapered, of similar length; lateral antennae curved, palps oblong tapered, directed laterally. Nuchal papilla minute. Eyes dark brown, reniform, placed towards posterior prostomial half, 1/6-1/7 as long as prostomial width. Nuchal organs as long as wide, about as wide as lateral antennal bases, displaced laterally above tentacular cirri of segment 1. Posterior prostomial notch shallow. Segments 1 and 2 dorsally reduced, segment 3 projected anteriorly.

Pharynx

Pharynx completely everted, contracted, basal region ¼ as long as total pharynx length; lower papillae mostly larger, globular to depressed, smaller globular papillae; dorsal surface with 3 small papillae, left side with 6 irregular rows of similar papillae, right side with about 10 irregular rows, larger papillae dorsolateral, smaller papillae ventrolateral ( Fig. 2C ); ventral surface smooth. Pharynx distal region hexagonal in cross-section, corners with 11-12 large, blunt conical ridges per row; aperture with 17 marginal lobate papillae ( Fig. 2D ).

Tentacular cirri and parapodia

Tentacular cirri all cirriform; dorsal cirri of segment 1 reaching segment 6 (chaetiger 3); dorsal cirri of segment 2 reaching segment 13 (chaetiger 10); dorsal cirri of segment 3 displaced ventrally reaching segment 11 (chaetiger 8). Segment 3 without neurochaetae. Segment 4 with dorsal and ventral cirri foliose, lanceolate, and neurochaetal lobe and neurochaetae. Parapodia with dorsal and ventral cirri lanceolate, ventral cirri tapered, projected beyond neurochaetal lobe, progressively longer posteriorly. Anterior chaetigers ( Fig. 2E ) with dorsal cirri tapered, about twice longer than wide; neurochaetal lobe with supracicular lobe slightly longer than subacicular one, about 15 compound spinigers per bundle; ventral cirri slightly projected beyond neurochaetal lobe. Median chaetigers ( Fig. 2F ) with slightly shorter, wider dorsal cirri, slightly longer than wide; neurochaetal lobe with supracicular lobe more clearly projected than subacicular one, about 12 compound spinigers per bundle; ventral cirri more clearly projected beyond neurochaetal lobe. Posterior chaetigers ( Fig. 2G ) with slightly shorter dorsal cirri, about twice longer than wide; neurochaetal lobe with supracicular lobe longer than subacicular one, about 10 compound spinigers per bundle. Neurochaetae with handle smooth, distally expanded, with fine denticles covering all expanded area, denticles progressively longer distally: blades long, delicate, often bent, cutting edge finely denticulate along almost all its length.

Posterior region

Tapered into a blunt cone; pygidium with anus terminal, anal cirri lost.

Oocytes

Visible in parapodial spaces, especially abundant in median chaetigers; each about 50-60 µm in diameter.

VARIATION

The nuchal organs are retracted if the pharynx is not exposed ( Fig. 3A ); they become visible after the pharynx is fully exposed ( Fig. 3F ). The eye shape varies from reniform to oval. Tentacular cirri changes with size; smallest specimens had their longest ones reaching chaetiger 2; they stabilize about reaching chaetiger 10 at 14 mm body length. The basal pharynx region is variable; it is often asymmetrical having regular rows on one side, and irregular ones on the other, and the number of rows varies from 5-6 regular ones to about 10 irregular ones. The dorsal surface is often smooth, but there can be up to 3-4 papillae in an irregular row. The ventral surface is always smooth. The dorsal cirri are narrower in anterior and posterior chaetigers, whereas they are slightly wider in median ones. The typical ciliary band in dorsal cirri are present along their posterior surface; staining helps making them more visible, but their length is progressively reduced in posterior chaetigers. It runs close to the inner margin as a straight band, running almost the entire length of the inner margin in median chaetigers ( Fig. 3B, C ), and becoming shorter and thinner in posterior chaetigers ( Fig. 3D, E ). Anal cirri are rarely present because the posterior region is delicate; if present, they are as long as the length from the last 2-3 chaetigers before the anus.

REMARKS

Anaitides albengai n. sp. resembles A. cf medipapillata sensu Villalobos-Guerrero & Tovar-Hernández, 2014 from Western Mexico because they have prostomium cordate, as long as wide, dorsal cirri lanceolate slightly longer than wide, and ventral cirri pointed. Their main differences are in the size of ventral cirri and in the shape and number of papillae per row in the basal pharynx region. In A. albengai n. sp. the ventral cirri extend beyond neurochaetal lobes, and there are 8-9 large, foliose papillae per row, whereas in A. cf medipapillata ventral cirri are as long as neurochaetal lobes, and there are 11 large, round papillae per row.

Figures

FIG. 2. — Anaitides albengai n. sp., holotype (MNHN-IA-TYPE2041): A, oblique lateral view of anterior region; B, anterior region, dorsal view (after Shirlastain-A); C, same, oblique lateral view; D, pharynx, anterior end, frontal view; E, chaetiger 50, left parapodium, anterior view (after Methyl green); F, chaetiger 120, left parapodium, anterior view (after Methyl green staining); G, chaetiger 220, right parapodium, anterior view (after Methyl green). Scale bars:A, 0.8 mm; B, 0.5 mm; C, E, 0.3 mm; D, 0.4 mm; F, G, 0.2 mm.

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.