Sabellaria jeramae, Nishi, Eijiroh, Matsuo, Kanako, Capa, Maria, Tomioka, Shinri, Kajihara, Hiroshi, Kupriyanova, Elena K. & Polgar, Gianluca, 2015

Nishi, Eijiroh, Matsuo, Kanako, Capa, Maria, Tomioka, Shinri, Kajihara, Hiroshi, Kupriyanova, Elena K. & Polgar, Gianluca, 2015, Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs, Zootaxa 4052 (5), pp. 555-568 : 557-562

Sabellaria jeramae n. sp.

Figures 2–8

Material examined. Holotype, CBM-ZW 1070, Pantai Jeram (= Jeram Beach, Selangor), 3°13′27″N, 101°18′13″E, west coast of the Malay Peninsula, tidal flat, site 0 28, 20 September 2013, coll. L. Ribero. Paratypes: CBM-ZW 1071–1079, same as holotype; KMNH IvR 500,789, same as holotype; ICHUM-5058–5077, 20 specimens, same as holotype; AM W. 47951, same as holotype.

Non-type material: YNU-M Iv, 10 specimens, same as holotype; YNU-M Iv, 23 specimens, type locality, 12 July, 2010, coll. L. Ribero.

Etymology. The specific name, a noun in the genitive case, is after Jeram Beach, the type locality of this species.

Diagnosis. Outer paleae with two pairs of distal teeth flanking a finely serrated (smooth under compound microscope) median plume, single type of middle paleae (ovate and concave, having rounded distal ends), and 2–4 pairs of thin, straight, or slightly curved nuchal spines. Median ridge and median organ present, latter conical and longer than wide. One pair of pointed lateral lobes on chaetiger 2. Parathoracic chaetae lanceolate with frayed distal ends. Abdominal chaetigers with notopodial uncini with double rows of 6–7 teeth each. Branchiae absent from posterior chaetigers.

Description. Measurements. Holotype 30 mm long, 2.0 mm at the widest part of thorax, with 21 abdominal chaetigers ( Fig. 2 A–B). Opercular lobe and thorax 2.5 mm long, 2.6 mm wide; parathorax 3.0 mm long; abdomen 25 mm long; cauda ca. 3.0 mm long and bent ventrally.

Colour pattern. Preserved specimens creamy white with some charcoal black specks and blotches on epithelium of opercular lobes, including median organ and median ridge, on both sides of outer surfaces of opercular lobes, and on edges of building organ and parathoracic neuropodia ( Fig. 3 A–C). Brown specks beneath row of conical cirri of crown. Second to third parathoracic chaetiger with a dark semi-circular band ventrally. Feeding tentacles (tentacular filaments) pale or brown with some reddish spots ( Fig. 3 B, D, F–G). Posterior abdominal notopodia light pink. Red specks also present, forming transverse bands on ventral surface of abdominal chaetigers and on cauda ( Figs 3 A, 8B–D). Body creamy white, with some darker spots on ventrum of anterior chaetigers and branchiae ( Figs 3 A, 7A–C).

Operculum. Two symmetrical lobes completely separated, with even width along its length, with distal opercular disc flat to slightly concave ( Figs 2 C–D, 3B–C), slightly sloping posteriorly toward dorsal midline ( Figs 2 A, C, 3D, F). Three rows of golden paleae arranged in concentric semicircles on each lobe ( Figs 2 D, 3F, H, 6A). Middle and outer paleae with tips directed outwards; inner paleae distal tips directed inwards ( Figs 2 D, 3H, 6A). Outer row with 47 geniculate paleae on each lobe, 0.4–0.5 mm long (excluding median plume) and 60 µm wide at base of blade. Blades flattened, slightly concave proximally, with smooth lateral margins and distal margins bearing two pairs of small tapering denticles flanking an acute larger one in the middle (median plume, Figs 4 A–C, 5A, 6A). Surface of blade with thecal ornamentation consisting of fine, closely-spaced, parallel, transverse thecal bands ( Figs 4 A–B, 5A, 6C). Median plume 50–80 µm long, with almost smooth edges, although some fine serrations visible under SEM ( Figs 4 C, 5E–H, 6C–E). Middle row with geniculate, single kind paleae, 24 on each lobe, with concave, slender ovate blades, with acute tip, 0.5–0.6 mm long ( Figs 4 D, 5B–C, 6B). Surface of blade with thecal ornamentation consisting of closely-spaced, parallel, transverse thecal bands ( Figs 4 D, 5B–C, 6B). Inner row with 30 geniculate paleae on each lobe, ovate and slightly concave proximally, with acute tip, more slender than middle paleae, 0.6–0.7 mm long ( Figs 4 E, 5D, 6B). Surface of blade with fine, parallel, transverse thecal bands ( Figs 5 D, 6B). Anterior outer margin of operculum with 16 conical papillae on each lobe ( Figs 2 A, C, 3E). Two pairs of nuchal spines on each side of anterio-dorsal midline of prostomium, with tapering, smooth, straight, or slightly curved tips ( Figs 2 C, 4F, 6F). Ventral margin of buccal cavity with over 30 transversal/diagonal rows of tentacular filaments on each lobe ( Figs 2 A, B, 3D–G). Median ridge on ventral surface of base of operculum extending from dorsal edge of upper lip of mouth to connect to edge of opercular lobes; median organ (detached lobe continuing from median ridge) conical, with blunt tip, longer than wider. Eyespots not visible.

Thorax. Composed of two chaetigers. Chaetiger 1 with single lobe-like neuropodium and elongated tapering lateral lobe on each side ( Fig. 2 A–B) and 8–10 capillary chaetae with plumose distal hood ( Fig. 7 I). Building organ U-shaped on ventral side. Chaetiger 2 with one pair of elongated, triangular-shaped lateral lobes with elongated tip surpassing first chaetiger, connecting branchiae to neuropodia ( Figs 2 A–B, 3A), ca. five capillary chaetae similar to those in chaetiger 1 ( Fig. 7 J). Twenty pairs of dorsal conical branchiae present from segment 2, with transversal cilial bands and glands ( Figs 2 C, 7D–E).

Parathorax. Composed of three parathoracic chaetigers ( Fig. 2 A–C). Notopodia without dorsal cirri. Two types of notochaetae in transverse rows, 10–11 lanceolate chaetae, with frayed tips ( Figs 2 B, 5D–E, 6G, 7K–L), interspersed with ca. 10 capillaries ( Fig. 7 K, M). Neuropodia with large, rounded lobes directed anteriorly with ca. 10 lanceolate chaetae interspersed with capillaries, similar to those in notopodia, but about half their overall size ( Fig. 7 N).

Abdomen. Composed of 21 chaetigers. Abdominal notopodia lobe-like, longer towards posterior chaetigers, each with a transverse row of uncini decreasing in number posteriorly. All chaetigers bearing uncini. Uncini of anterior abdominal chaetigers with seven transverse rows of teeth with characteristic arrangement: basal peg, median 6–7 rows with two aligned teeth each, and distal rows with 1–3 teeth each ( Figs 5 L, 6G, 8F–G). Uncini of mid-abdominal and posterior chaetigers similar to those in anterior abdominal chaetigers ( Fig. 8 H–I). First abdominal segment (chaetiger 6) with rounded neuropodial lobe below neurochaetae ( Fig. 8 A). Second and following chaetigers with conical lobe. Neuropodia with bundles of 10–15 plumose capillaries, arranged in two rows; dorsal row with slightly larger chaetae ( Fig. 8 E).

Cauda. Bent ventrally for as long as ca. 8 abdominal chaetigers; with no signs of segmentation ( Fig. 8 B–D).

Variation. Paratypes 10–35 mm long, 1.0– 2.2 mm wide at thorax; operculum 2.0– 3.2 mm long, 1.0– 2.8 mm wide; 16–24 abdominal chaetigers; cauda long, 7–8 mm in length. Colour pigmentation varying slightly among specimens; darker speckles may be more or less abundant and widely distributed on operculum and anterior chaetigers. Reddish speckles on the dorsum of posterior abdominal chaetigers and cauda varying slightly in intensity and coverage among preserved material examined. Eyespots on median ridge or median organ not observed in any preserved specimens. Paratypes with 13–18 conical papillae on each lobe, 24–36 paleae on outer row, 20–25 on middle row, and 30–46 on inner row. Median plumes of outer paleae damaged in some paratypes. Two to four pairs of nuchal spines on each side of anterio-dorsal midline of prostomium on paratypes similar to those described in holotype. Tentacular filaments extending beyond length of operculum in some specimens. Number of abdominal chaetigers provided with branchiae 15–20.

Tube. Length up to 10 mm, tube aperture 3.0–4.0 mm in diameter. Tube constructed of sand granules and shell debris; no hood or ornamentation in opening; inner side coated with thin, hardened mucous layer.

Reproductive features. Females store brown (after preservation) oocytes about 50 µm in diameter ( Fig. 7 H) in thoracic and anterior abdominal chaetigers ( Fig. 7 G).

Type locality. Jeram Beach, Jeram, Selangor State, Malaysia.

Distribution. Along the Selangor coastline near Kuala Lumpur, Malaysia. Currently, no records of the species outside of Selangor State.

Taxonomic remarks. Sabellaria jeramae n. sp. is characterised by a unique combination of paleal morphology attributes and opercular traits. Type specimens bear outer paleae with two or three distal teeth flanking and finely serrated (visible only under electron microscope) median plume on both sides, a single type of middle paleae (concave and with rounded distal ends), and 2–4 pairs of thin, straight, or slightly curved nuchal spines. Similar to our new species, congeners having a single (long) type of middle paleae with rounded or blunt tips include: S. bellis Hansen, 1882 , S. grueti Kirtley, 1994 , S. javanica Augener, 1934 , S. miryaensis Parab & Gaikward, 1990 , S. moorei Monro, 1933 , S. nanella Chamberlin, 1919 , S. vulgaris Verrill, 1873 (see comparative table in Nishi et al. 2010; Hutchings et al. 2012). Of these, only S. grueti , S. bellis , and S. vulgaris have a simple medial plume in outer paleae, with smooth or finely serrated margins, but these species have a simple, short, not frayed central tooth in outer paleae, while in S. jeramae n. sp. the central tooth is long, frayed). Also, inner paleae of S. jeramae n. sp. lack denticles while inner paleae of S. bellis has distal denticles. Outer paleael blade of S. jeramae n. sp. is longer and narrower in distal part than basally, ones of S. grueti are elongate ( Kirtley 1994). Sabellaria jeramae n. sp. is distinguished from the recently described Brazilian species S. guamare Dos Santos et al., 2014 by the morphology of middle and inner paleae: the former has a simple distal tip ( Fig. 3 B), the latter has tips with dominant and lateral teeth ( Dos Santos et al. 2014).

Reef structure. The reef system consisted of several elongated barriers parallel to the coastline, spanning several hundred meters long and 50–200 m wide from the land to the sea ( Polgar et al. 2015). Sparse smaller clumps and ball-shaped structures were present along the barriers’ margins. All aggregations were raised about 0.5 m above the substrate. The overall mean diameter of the tube opening was 2.25 ± 0.77 mm (0.49–4.53, n = 210). The average density of polychaetes (pooled samples) was 89,058 ± 25,953 tubes/m2 (26,000–131,600 tubes/m2, n = 34, in Polgar et al. 2015).

Figures

FIGURE 2. Sabellaria jeramae n. sp., outline drawings of the holotype. A—anterior end, lateral view, B—same, ventral view, C—same, dorsal view, D—anterior view of opercular disc showing the rows of paleae. Scales 1 mm (upper in A-C, lower in D).

FIGURE 3. Sabellaria jeramae n. sp., light microscope images of a paratype (AM W. 47951). A—complete specimen, ventral view, B—anterior end, ventral view, C—anterior end, dorsal view, D—anterior end, side view, showing rows of tentacular filaments (lines), E—detail of the edge of operculum, with opercular papillae and tentacular filaments, F—longitudinal section showing structures between opercular lobes, G—detail of median organ and median ridge, H—arrangement of paleae. Abbreviations: bo, buccal organ; br 2, br 3, branchial chaetigers 2, 3; ip, inner paleae; mo, median organ; mp, middle paleae; mr, median ridge; op, outer paleae; pa, opercular papillae; tf, tentacular filaments. Scale: 2 mm in A, 1 mm in B-D, F, 0.5 mm in E, G, H.

FIGURE 4. Sabellaria jeramae n. sp., compound microscope images. A – C—outer paleae, D—middle paleae, E—inner paleae, F—nuchal spines. Scale: 0.2 mm in A, B, D, E, 0.05 mm in C, 0.025 mm in F.

FIGURE 5. Sabellaria jeramae n. sp., outline drawings of paleae, chaetae, hooks and uncini. A—outer paleae, B, C—middle paleae, D—inner paleae, E – H—distal end of outer paleae, I—nuchal hook (spine), J—parathoracic chaetae, K—thoracic chaetae, L—abdominal uncini. E – L are drawn from SEM figures. Scale: 100 µm in A—I, 20 µm in J and K, 10 µm in L.

FIGURE 6. Sabellaria jeramae n. sp., scanning electron micrographs. A—operculum, B—middle (below) and inner (center to upper) paleae, C—close-up of outer paleae, D—E—distal end of outer paleae, F—nuchal spines, G—abdominal uncini. Scales on images. Scale: 0.2 mm in A, 0.1 mm in B, D, 0.05 mm in C, E, 0.02 mm in F, 0.01 mm in G.

FIGURE 7. Sabellaria jeramae n. sp., stereo and compound microscope images of thoracic and parathoracic features. Aparathorax, dorsal view, B—same, anterio-lateral view, C—same, lateral view, D—thoracic branchiae, E—detail of branchial ciliation, F—details of branchial glands, G—interior of parathoracic chaetigers filled with eggs, H—detail of eggs, Ineurochaetae of chaetiger 1, J—notochaetae of chaetiger 2, K—parathoracic notochaetae, L—detail of distal ends of parathoracic oar-like notochaetae, M—detail of distal end of parathoracic thin capillary notochaetae, N—parathoracic neurochaetae. Abbreviations: bo, buccal organ; ch 1 – 3, chaetiger 1 – 3; cn 1, cirrus neuropodium chaetiger 1; ll, lateral lobe; ne 3 – 5, neuropodia chaetiger 3 – 5; no 3 – 5, notopodia chaetigers 3 – 5. Scale: 1 mm in A, B, 0.5 mm in C, D, G, 0.25 mm in E, 0.1 mm in K, N, 0.05 mm in F, H, 0.02 mm in I, J, K, M.

FIGURE 8. Sabellaria jeramae n. sp., light and compound microscope images of abdominal and caudal features. A—first two abdominal chaetigers abdominal notopodia and neuropodia, B—posterior abdominal chaetigers and cauda, dorsal view, Csame, lateral view, D—same ventral view, E—abdominal neurochaetae, F—uncini anterior abdominal chaetigers, G—same, mid-abdominal chaetigers, H, I—same, posterior abdominal chaetigers. Scale: 0.5 mm in A-D, 0.02 mm in E-I.