Alcyonosyllis aidae Álvarez-Campos, Martín & Aguado, 2013, n. sp.
Creators: name: Álvarez-Campos, Patricia
name: Martín, Guillermo San
name: Aguado, M. Teresa
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Phyllodocida
Syllidae
Alcyonosyllis
Alcyonosyllis aidae

description: Alcyonosyllis aidae, n. sp.
Figs 1 –4
Material examined. HOLOTYPE (NMA 004438), 7 paratypes (NMA 0 0 4439, MNCN 16.01/14693) and 4 detached stolons (MNCN 16.01/14694) fixed in formaldehyde; 26 paratypes fixed in ethanol (NMA 0 0 4440, MNCN 16.01/14695) and 2 mounted for SEM (MNCN 16.01/14692). Philippines Islands: "Mainif point", between Balayan Bay and Batangas bay, Luzón Island, 13º40’48’’N – 120º51’20’’E, Dendronephthya sp. on soft bottom, 10 m deep, 8 December 2010.
Comparative material. Alcyonosyllis phili, one paratype (MNCN 16.01/ 16.01/8712), East Arm Port, Darwin Harbour, Darwin, Northern Territory, Australia, 12º29'4"S – 130º53'9"E; Alcyonosyllis glasbyi, 7 paratypes (MNCN 16.01/9043–9049) Ohura Bay, Shimoda, Izu Peninsula, Shizuoka, Japan, 34º57'N – 138º57'E, in Melithaea flabellifera from shallow water of rocky shore, 3–15 m depth, May-July 2002. Alcyonosyllis exiliformis, 1 specimen mounted for SEM (MNCN 16.01/11006), Ubara, Katsuura, Boso Peninsula, Japan, 35º07'55''N – 140º17'16''E, April 1995.
Description. Holotype longest complete specimen, 13 mm long, 0.35 mm wide (without parapodia), 78 chaetigers; developing stolon of 4 mm long, 1 mm wide, 19 chaetigers; stolons remarkably wider than stocks (Fig. 1 A, B), without capillary natatory chaetae, only neurochaetae. Body elongated, relatively slender, tapered on tips, brightly coloured, with a median longitudinal, slender red line, densely pigmented, and two wider lateral bands less densely pigmented, giving a tri-lineate appearance (Figs 1 A–D; 2A–C); in some specimens, lateral lines appearing as triangular areas on each side (Figs. 1 A, B); colour pattern starts on posterior part of prostomium (Fig. 2 A). Some specimens more strongly pigmented than others; some specimens with only three red spots on posterior segments, one central and two laterals, close to insertion of dorsal cirri. One rounded red spot on bases of dorsal cirri in some specimens. Living specimens can change the concentration of pigment on laterals and which changes their appearance, from uniform lateral bands to sinuose (as shown in Fig. 1 A–D). Prostomium oval to semicircular (Figs 2 A, 4A, B), with two pairs of small eyes in trapezoidal arrangement, all similar in size (Fig. 2 A). Median antenna inserted slightly anteriorly to posterior pair of eyes, usually posteriorly directed, about three times longer than combined length of palps and prostomium (Fig. 2 A); lateral antennae inserted on anterior margin (Figs 2 A, 4A, B), in front of anterior pair of eyes, about 2/3 of median antenna length. Peristomium well defined, slightly shorter than subsequent segments, with a small lip covering posterior part of prostomium (Figs 2 A, 4A, B); dorsal tentacular cirri (peristomial cirri) somewhat longer than median antenna; ventral tentacular cirri similar in size to lateral antennae (Fig. 2 A). Dorsal cirri of first chaetiger distinctly longer than median antenna, about 4.5 times longer than chaetiger 1 width; dorsal cirri of second chaetiger distinctly shorter, similar to second chaetiger width; dorsal cirri of third chaetiger slightly shorter than dorsal cirri of first chaetiger (Fig. 2 A); from fifth chaetiger backwards alternating short cirri, similar or slightly longer than body width, and long cirri, about 3.5 times longer than body width (Fig. 2 B, C), shorter on posterior segments. Antennae, tentacular and dorsal cirri smooth to weakly articulated, filiform (Figs 2 A–C, 4A, B); long cirri of most anterior segments slightly rugose and weakly articulated (Figs 2 A, 4A, B). Dorsal cirri of first chaetiger somewhat thicker than remaining (Figs 2 A, 4A, B). Parapodia blunt, short, slightly bilobed distally (Figs 2 B, C, 3C, 4E). Ventral cirri digitiform. Chaetae all simple, relatively thick, distally hooked, with subdistal boss more or less marked; 2–3 chaetae per parapodium, unidentate or bidentate, with distal tooth larger than proximal one; single chaeta in some parapodia of some specimens. Some variability in distribution of chaetae; anterior and midbody parapodia usually with 2 chaetae, one longer bidentate and another unidentate, or sometimes two, one short and unidentate, with small boss (Figs 3B, 4C, D); posterior parapodia with three chaetae, two unidentate and one bidentate (Fig. 3C) or one unidentate, without boss, and two distinctly bidentate (Fig. 4E). Up to four chaetae on anterior parapodia of some specimens, two larger and two smaller. Anterior parapodia with three slender, straight, distally broad aciculae; single acicula in posterior parapodia. Pharynx extending through three segments; pharyngeal tooth on anterior margin. Proventricle short, extending through 2.5–3 segments (Fig. 2 A), with about 30 muscle cell rows. Pygidium small, with 2 long anal cirri, similar to dorsal cirri.
Reproductive mode. Several specimens with attached developing stolons, about 25 chaetigers, with a tail of regeneration on ventral side, just in front of head of stolon (Figs 1 A, arrow, 3A). Detached stolons 5 mm long, 0.5 mm wide, with about 25 chaetigers, with similar colour pattern as stock, (Fig. 1 C), usually more marked, and two red spots on each segment on ventral side (Fig. 1 B). They present a “head” bilobed, one pair of dorsal eyes, one pair of ventral eyes, two short unarticulated antennae, and two small palps, ventrally directed (Figs 1 A–E, 3A). Three to four chaetae per parapodium, two bidentate with subdistal boss and one or two unidentate, with or without boss; all of them similar to those of the adult, embed within the parapodium for most of their length. The stolons do not present natatory chaetae.
Remarks. Alcyonosyllis aidae n. sp. is characterized by its colour pattern, which is different to all other species of the genus, having a tri-lineate appearance, the first pair of dorsal cirri thicker than remaining and rugose, and 2–3 chaetae per parapodium, bidentate with small proximal tooth and unidentate with or without subdistal boss. It is close to Alcyonosyllis sp. (Glasby & Aguado 2009) in the number and shape of chaetae although the distal tooth of bidentate chaetae is larger in the new species; furthermore, aciculae on anterior parapodia are remarkably different between these speces and the distinctly shaped cirrophores (as a constricted rings) of Alcyonosyllis sp. is not present in Alcyonosyllis aidae n.sp. Alcyonosyllis bisetosa has only two chaetae per parapodium, with a stronger boss and larger proximal tooth in some parapodia. Alcyonosyllis xeniaeicola has 2–4 chaetae per parapodium, all unidentate as those from Alcyonosyllis hinterkircheri. Alcyonosyllis phili and Alcyonosyllis glasbyi present chaetae with very slight subdistal boss and bidentate chaetae with a minute tooth below the hook, much shorter than those from the bidentate chaetae of the new species.
Habitat. On soft coral Dendronephthya sp. living on shallow sand.
Distribution. Only known from the type-locality.
Etymology. The species is named in honor to Aida Verdes, colleague and friend, for her useful advice and her help collecting and sorting material in different field trips.
description: Published as part of Álvarez-Campos, Patricia, Martín, Guillermo San & Aguado, M. Teresa, 2013, A new species and new record of the commensal genus Alcyonosyllis Glasby & Watson, 2001 and a new species of Parahaplosyllis Hartmann-Schröder, 1990, (Annelida: Syllidae: Syllinae) from Philippines Islands, pp. 156-168 in Zootaxa 3734 (2) on pages 158-163, DOI: 10.11646/zootaxa.3734.2.4, http://zenodo.org/record/216939