Saphobranchia canela, Salazar-Vallejo, 2020

Salazar-Vallejo, Sergio I., 2020, Four new deep-water flabelligerid species from Pacific Costa Rica (Annelida Sedentaria, Flabelligeridae), Zootaxa 4885 (4), pp. 560-578 : 568-569

Saphobranchia canela n. sp.

urn:lsid:zoobank.org:act:61599631-4468-48CA-B224-BAAC8F2DE8AB

Figures 4 ; 8 C–E

Diagnosis. Saphobranchia with tunic adhering sand particles, including dorsal papillae; median chaetigers with neurochaetal tips falcate, anchylosed region 1/2–1/3 chaetal length.

Type material. Holotype ( SIO A1332 ), Alvin dive 4502, Costa Rica Mound 12 (08°55’40.80” N, 84°18’46.80” W), 1000 m, 23 Feb. 2009, G. Rouse & D. Huang, coll. [ MW 172257 ] . Paratypes: One specimen ( SIO A1321 ), Alvin dive 4501, Costa Rica Mound 12 (08°55’48.00” N, 84°18’46.80” W), 1008 m, 22 Feb. 2009, G. Rouse & D. Huang, coll. [ MW 172258 ]. One specimen ( SIO A1939 ), Alvin dive 4589, Mound 12 (08°55’48.00” N, 84°18’43.20” W), 998–1018 m, 10 Jan. 2010, G. Rouse, coll. [ MW 172259 ]. An anterior fragment ( SIO A9607 ), Alvin dive 4974, black slurp, Mound 12 (08°55’48.00” N, 84°18’46.80” W), 996 m, 20 Oct. 2018, L. Levin & K. Metcalfe, coll. One specimen ( SIO A9909 ), Alvin dive 4989 RedSlurp, Jaco Scar (09°07’04.80” N, 84°50’24.00” W), 1785 m, 4 Nov. 2018, L. Levin & D. Casagrande, coll. [ MW 172260 , MW 172261 , two specimens sequenced] .

Description. Holotype (SIO A1332), mature female, anterior fragment, brownish; chaetae cinnamon in colour. Body tapered, markedly contracted, introvert exposed, directed ventrally, anterior body wall eroded, venter anteriorly and posteriorly eroded, expanded ( Fig. 4A ); dorsum with sand particles, looks tuberculate; 9 mm long, 2 mm wide, cephalic cage chaetae 5 mm long, 21 chaetigers.

Tunic papillated, sediment particles include sand and silt, adherent along body and papillae ( Fig. 8C ). Dorsum with 2–3 transverse rows of papillae per segment, most damaged after removal of sand particles, two larger papillae in a row close to mid-dorsal line. Single larger blunt conical papillae in central notopodial fascicle, one inter-ramal, and another below neurochaetal fascicle ( Fig. 4D ). Venter with smaller, digitate papillae, 5–6 alternating rows per segment ( Fig. 8D ).

Anterior end exposed, slightly eroded, appendages detached ( Fig. 4B ). Branchiae marginal, eight scars of similar diameter. Palps size proportion to branchiae unknown. Nephridial lobe scars visible below bases of second lowermost branchiae. Prostomium slightly projected, caruncle short, reaching branchial plate. Eyes not seen. Upper and lower lips reduced, lateral lips massive, projected laterally. Living specimen with eight cirriform, branchial filaments of similar thickness, half as wide as palps, and slightly longer than them ( Fig. 8E ).

Cephalic cage chaetae 2.5 times longer than body width. Chaetigers 1–2 forming cephalic cage, distorted; right chaetae of chaetiger 1 directed posteriorly, those of chaetiger 2 directed anteriorly; chaetiger 3 with chaetae directed laterally, notochaetae 1/2–2/3 as long as those in previous chaetigers. Chaetae arranged in short rows, dorsolateral fan-shaped fascicles from chaetiger 3 to end of fragment.

Chaetiger 1 with six notochaetae and three neurochaetae per side, longest ones basally to medially anchylosed, distally articulated, shorter ones completely articulated, articles 4–6 times longer than wide, progressively longer. Chaetiger 2 with four notochaetae, and seven shorter neurochaetae, notochaetae 2/3 as long as those of chaetiger 1, anchylosed section progressively shorter in smaller chaetae; neurochaetae shorter, thicker than those of chaetiger 1, similar to those present in posterior chaetigers, 2–3 times longer than wide, slightly longer distally.

Anterior dorsal margin of chaetiger 1 eroded, without tunic, with two larger tapered papillae. Chaetigers 1–4 distorted, chaetigers 1–2 expanded, twice longer than following ones. No chaetal transition from cephalic cage chaetae to body chaetae; all neurochaetae multiarticulate. Gonopodial lobes not seen ( Fig. 4C ). Oocytes inside ovary, cinnamon in colour, no oil droplets between oocytes, each about 60–80 μm in diameter.

Parapodia poorly developed, chaetae emerge from body wall. Parapodia lateral; median neuropodia ventrolateral. Notopodia with a larger central conical papilla, slightly larger than interramal papilla ( Fig. 4D ); neuropodia with a large, digitate basal papillae (conical before removal of sediment particles).

Median notochaetae arranged in short transverse rows, chaetal fascicles fan-shaped, directed dorsally, slightly longer than body width. All notochaetae multiarticulate capillaries; 9–10 per bundle, central notochaetae with basally anchylosed region half as long as total chaetae, 1–2 median articles twice longer than wide, then 4–5 times longer than wide, progressively longer distally, tips straight ( Fig. 4E ). Neurochaetae 2/3 as long as body width; 8 per bundle, anchylosed region 2/5–1/3 total length ( Fig. 4F ), 1–2 median articles as long as wide, or slightly longer than wide, progressively longer up to 3–4 times longer than wide subdistally; tips falcate ( Fig. 4F , inset).

Posterior region unknown.

Etymology. The specific epithet is from the Spanish word for cinnamon, canela, and indicates the cinnamon colour of chaetae and body wall. The Spanish word comes from the French canelle, or from the Italian canella, both meaning ‘small cane’ and in Spanish refers to the cinnamon tree cortex that, once dried, twists around itself forming small canes. The specific name is regarded as a noun in apposition ( ICZN 1999, Art. 31.2).

Variation. An anterior fragment from the type locality (SIO A1321) 5 mm long, 1 mm wide, 16 chaetigers, cephalic cage chaetae broken 1 mm long. It has integument brownish, tunic partially eroded, a few sand particles in posterior segments; many chaetae broken including those of chaetigers 1–2; anterior end fully exposed, partially eroded, cephalic appendages lost; gonopodial lobes not seen. A small specimen from the type locality (SIO A1939) has the anterior end fully exposed, appendages detached, ventral pharyngeal organ everted, without posterior end; 15 mm long, 2 mm wide, 27 chaetigers. Anterior chaetigers damaged, many chaetae broken, cephalic cage chaetae 2.5 mm long, tunic granulose with sand particles; gonopodial lobes not seen. Median chaetigers have slightly less notochaetae, same number of neurochaetae, but body wall and chaetae are paler. The interramal papillae is as long as 1/5 notochaetal, or 2/5 neurochaetal length. Another fragment (SIO A9607) distorted, anterior end exposed, slightly eroded, cephalic appendages lost; 6 mm long, 1.8 mm wide, 10 chaetigers. Cephalic cage chaetae 6.5 mm long; chaetiger 1 with seven notochaetae and five neurochaetae; chaetiger 2 with 5–7 notochaetae, 2/3 as long as those of chaetiger 1, and 6–7 neurochaetae, about 1/3 as long as those of chaetiger 1. Chaetiger 3 with smaller chaetae, neurochaetae directed laterally. Gonopodial lobes not seen. Another paratype (SIO A9909) is almost complete, integument brownish, tunic with sand particles. Body anteriorly swollen, twisted medially, tapered posteriorly; 14 mm long, 2 mm wide (widest by chaetigers 5–6, 2.5 mm), cephalic cage 4 mm long, 29 chaetigers. Chaetigers 1–2 lateral, chaetiger 1 with five notochaetae, 3–4 neurochaetae; chaetiger 2 with three notochaetae half as long as those in chaetiger 1, and 5–6 neurochaetae directed anteriorly. Anterior end visible but not exposed, appendages detached. Median chaetigers with seven notochaetae and eight neurochaetae per bundle; reduced in size and number posteriorly.

Remarks. Saphobranchia canela n. sp. resembles S. acafi ( Teixeira, Rizzo & Santos, 2015) n. comb., because they have sand particles along body, median chaetigers with 7–8 notochaetae per bundle, and neurochaetae with long articles distally. Their main differences are the length of notochaetae, the number of neurochaetae along median chaetigers, and the pigmentation of body wall and chaetae. In S. canela , the notochaetae are longer than body width, there are eight neurochaetae per bundle, and body wall and chaetae are cinnamon in colour, whereas in S. acafi notochaetae are half as long as body width, there are five neurochaetae per bundle, and body wall and chaetae are yellowish.

On the other hand, S. canela n. sp. differs from the two other newly described species: S. ilys n. sp. and S. omorpha n. sp. especially because of the body wall and chaetal pigmentation, being brownish, or cinnamon in colour in the former species, because the two other species have a pale body wall, and paler chaetae.

Distribution. Off Pacific Costa Rica in 998–1785 m depth.

Figures

FIGURE 4. Saphobranchia canela n. sp., holotype (SIO A1332). A. Dorsal view. B. Anterior end, oblique frontal view (BS: branchial scar, LL: lateral lip, NS: Nephridial lobe scar, PS: palp scar). C. Anterior region, ventral view. D. Chaetiger 14, right parapodium, posterior view. E. Same, notochaetal basal, medial and distal regions. F. Same, neurochaetal basal and distal regions (inset: neurochaetal tip). Scale bars.- A: 1.1 mm, B: 150 μm, C: 0.65 mm, D: 0.46 mm, E: 140 μm, F: 0.8 mm.

FIGURE 8. Living specimens. A. Lamispina polycerata n. sp., holotype (SIO A9842), anterior fragment, left lateral view. B. Same, posterior fragment, dorsal view. C. Saphobranchia canela n. sp., holotype (SIO A1332), dorsal view. D. Same, ventral view. E. Same, anterior end, frontal view (Br: branchia, Pa: palp). F. S. ilys n. sp., holotype (SIO A 9605), dorsal view. G. Same, ventral view. H. S. omorpha n. sp., holotype (SIO A9595), dorsal view. I. Same, ventral view. Scale bars: A, B: 1.0 mm; C, D: 2.2 mm; E: 0.4 mm; F, G: 3.5 mm; H, I: 3.7 mm (Photos: Greg Rouse).