Anguillosyllis lanai, Barroso, Rômulo, Paiva, Paulo Cesar De, Nogueira, João Miguel De Matos & Fukuda, Marcelo Veronesi, 2017

Barroso, Rômulo, Paiva, Paulo Cesar De, Nogueira, João Miguel De Matos & Fukuda, Marcelo Veronesi, 2017, Deep sea Syllidae (Annelida, Phyllodocida) from Southwestern Atlantic, Zootaxa 4221 (4), pp. 401-430 : 424-427

Anguillosyllis lanai sp. nov.

Figure 13–14

Type material. Project ‘Habitats ’. Holotype (MNRJP 1186): 22°49’22”S, 40°8’19”W, 1864 m, 11 May 2008; Project ‘Ambes ’: Paratype (ZUEC POL 19880): 19°42’01.8”S, 39°22’21.4”W, 1333 m.).

Material examined. Project ‘Habitats ’: 23°25’19”S, 40°35’37’W, 2491 m: 1 spec. (MZUSP 2947), 17 Feb 2009; 23°3’34”S, 40°41’55”W, 1285 m: 1 spec. (MZUSP 2945), 16 Jan 2009; 23°8’25”S, 40°36’40”W, 1954 m: 1 spec., 27 Jan 2009. Project ‘ AMBES ’: 19°3’13”S, 37°45’37”W, 2426 m: 3 specs (MZUSP 2919), 6 Dec 2011; 19°3’45”S, 37°47’28”W, 1928 m: 3 specs (MZUSP 2935), 29 Jan 2012; 19°3’55”S, 37°45’8”W, 2993 m: 1 spec. (MZUSP 2920), 5 Dec 2011; 19°3’55”S, 39°45’8”W, 2993 m: 2 specs (ZUEC 19884), 5 Dec 2011; 19°40’8”S, 39°7’22”W, 1035 m: 1 spec., 13 Dec 2011; 20°25’16”S, 39°27’20”W, 1918 m: 2 specs (MZUSP 2931), 7 Jan 2012; 20°29’3”S, 38°23’15”W, 2504 m: 3 specs (MZUSP 2923), 22 Dec 2011; 20°41’33”S, 39°35’14”W, 1914 m: 2 specs (MZUSP 2921), 27 Dec 2011; 20°49’23”S, 38°17’11”W, 2997 m: 2 specs (MZUSP 2922), 23 Dec 2011; 20°54’14”S, 38°56’10”W, 2519 m: 1 spec. (MZUSP 2930), 4 Jan 2012; 20°8’42”S, 39°7’29”W, 1922 m: 1 spec. (MZUSP 2933), 6 Jan 2012; 20°8’45”S, 39°7’31”W, 1927 m: 5 specs (MZUSP 2954), 16 Jun 2013; 21°36’42”S, 39°49’25”W, 1333 m: 6 specs (MZUSP 2926), 8 Jan 2012; 21°4’51”S, 40°4’14”W, 1300 m: 4 specs (MZUSP 2924 m), 31 Dec 2011; 21°6’30”S, 39°38’36”W, 1889 m: 2 specs (MZUSP 2925), 31 Dec 2011; 21°6’38”S, 39°38’31”W, 1889 m: 1 spec. (MZUSP 2928), 9 Jun 2013; 21°9’39”S, 38°52’7”W, 2502 m: 1 spec. (MZUSP 2929), 10 Jun 2013; 22°49’22”S, 40°8’19”W, 1864 m: 1 spec., 11 May 2008.

Additional material examined: Anguillosyllis capensis — South Africa, off Cape Province (34°51’S, 23°41’E, 183 m deep): 1 spec. ( BMNH 1963.1 .29, holotype), coll. J.H. Day, 30 Nov 1960, det. J.H. Day, 1963. Braniella pupa — USA, off New England : 1 spec. ( ZMH P-13585, paratype?), coll. Allan Hancock Foundation, det. Hartman & Fauchald, 1971 ; USA, off Delaware (38°44’36”N 73°03’06”W, 183 m deep): 1 spec. ( USNM 56762 ), coll. “ VIMS for BLM/ MMS ”, 19 Mar 1976, det. G.R. Gaston ; USA, Georges Bank, Northern Slope (41°33’26”N 68°58’36”W, 117 m deep): 1 spec. ( USNM 103505 ), coll. BLM/ MMS, 27 Feb 1977, det. University of Delaware.

Description. Fragile bodies, usually missing antennae and most cirri, complete specimens with 10 chaetigers, largest specimen examined complete, 2 mm long, 0.2 mm wide. Palps elongate, distally acute, completely fused or with only minute distal notch, occasionally with faint line of fusion. Prostomium ovate, broader than long; eyes absent, antennae cirriform to ovoid ( Fig. 13 A–B; 14A). Peristomium shorter than subsequent segments, with 1 pair of ovate, papilliform peristomial cirri, smaller than lateral antennae ( Fig. 13 A–B; 14A). Dorsal cirri long, slender, often coiled over dorsum, most cirri broken or missing, not present on chaetiger 2 ( Fig. 13 A, I), frequently only cirrophores left; parapodial glands as slightly swollen areas dorsally, close to bases of dorsal cirri, with granular material of unknown nature, approximately rounded to polyhedral under SEM ( Fig. 13 A, H; 14A, F–G). Ventral cirri digitiform, inserted at mid-length of parapodial lobes, not reaching tip ( Fig. 14 B). Parapodia distally rounded to weakly bilobed, in such case posterior lobe progressively slightly larger towards posterior body, or only short, nearly inconspicuous posterior lobe present. Anterior and midbody parapodia with ~15 compound chaetae each, posterior body with ~5–10 compound chaetae each; chaetae heterogomph, with long, unidentate, finely spinulated to smooth blades (spinulation nearly inconspicuous under compound microscope); conspicuous dorso-ventral gradation in length, blades 160–7 µm, 170–30 µm and 170–20 µm long on anterior, mid- and posterior body chaetigers, respectively ( Fig. 13 E–G; 14C–D). Parapodia throughout usually with 2 aciculae each, aciculae away from each other at tip of parapodium, one usually extending anteriorly and other posteriorly to chaetae, frequently with tips protruding from parapodial lobes ( Fig. 13 D); aciculae subdistally slightly enlarged, distally acute ( Fig.14 E). Pharynx through 1.5–2 chaetigers, border surrounded by ~10 soft, elongate, digitiform papillae (Fig, 13C), tooth absent. Proventricle barrel-shaped to heart-shaped, through 2.5–3 chaetigers (0.25–0.35 mm long), with ca. of 12 rows of muscle cells ( Fig. 14 A).

Remarks. Anguillosyllis lanai sp. nov. has completely fused palps, parapodial lobes distally rounded, bilobed or with posterior lobe only, and structures near parapodial bases which we consider as parapodial glands, because their location is in agreement with parapodial glands found in other species of syllids. The species most similar morphologically to A. lanai sp. nov. is A. pupa , since both species have completely or nearly completely fused palps and ventral cirri inserted at mid-length of parapodial lobes. However, A. lanai sp. nov. differs from A. pupa as this latter species has a proventricle with 20–25 rows of muscle cells (against ~12 rows as in A. lanai sp. nov.); and post-chaetal lobes conspicuously larger than in A. lanai sp. nov. (see Hartman 1965, Pl. 8; Aguado & San Martín 2008, Fig. 2 A–B). Anguillosyllis lanai sp. nov. also differs from A. capensis , since in that species the proventricle presents more rows of muscle cells (30 rows), and the parapodial lobes have distinctly larger, elongate post-chaetal lobes (see Aguado & San Martín 2008, Fig. 1 ). Finally, A. lanai sp. nov. differs from A. palpata because the latter species presents palps separated from each other for at least half of their length, longer blades of compound chaetae (up to 450 µm long, as opposed to 170 µm long, as in A. lanai sp. nov.), and by the adults of that species having 11, instead of 10 chaetigers, as in A. lanai sp. nov.

Geographic distribution and bathymetric range. Anguillosyllis lanai sp. nov. was found in Campos and Espírito Santo basins, between 1035–2997 m deep.

Etymology. This species is dedicated to Paulo Lana, responsible for an enormous increase in the knowledge of marine invertebrates, especially polychaetes, inspiring new generations of researchers.

Figures

FIGURE 1. Exogone anomalochaeta. (A) anterior body, dorsal view; (B – C) falcigers, anterior and mid- to posterior body chaetigers, respectively; (D, H) aciculae, anterior and posterior body chaetigers, respectively; (E – F) dorsal simple chaetae, anterior and posterior body chaetigers, respectively; (G) ventral simple chaeta.

FIGURE 2. Exogone anomalochaeta, SEM. (A) entire worm, dorsal view; (B – C) anterior body, dorsal and ventral views, respectively; (D) detail of prostomium and peristomium, right dorso-lateral view; (E) nuchal organ; (F) dorsalmost falciger, midbody chaetiger; (G – H) chaetae, chaetiger 1; (I) chaetae, midbody chaetiger.

FIGURE 13. Anguillosyllis lanai sp. nov., SEM. (A) entire worm, dorsal view; (B – C) close ups of the anterior end, dorsal view, pharynx everted; (D) parapodium, dorsal view, arrow points to acicula; (E – F) falciger (left) and spiniger-like chaeta (right), anterior and midbody chaetigers, respectively; (G) compound chaetae; (H) granules of parapodial glands; (I) posterior end, dorsal view.

FIGURE 14. Anguillosyllis lanai sp. nov. (A) entire worm, dorsal view; (B) midbody parapodium, posterior view; (C – D) falcigers and spiniger-like chaetae, respectively; (E) tip of acicula; SEM: (F) left-hand parapodia, chaetigers 2 – 3, dorsal view; (G) close up of a parapodial gland, chaetiger 3.