Terebellides kirkegaardi Parapar, Martin, and Moreira 2020
- Dataset
- On the diversity of Terebellides (Annelida, Trichobranchidae) in West Africa, seven new species and the redescription of T. africana Augener, 1918 stat. prom.
- Rank
- SPECIES
- Published in
- Parapar, Julio, Martin, Daniel, Moreira, Juan (2020): On the diversity of Terebellides (Annelida, Trichobranchidae) in West Africa, seven new species and the redescription of T. africana Augener, 1918 stat. prom. Zootaxa 4771 (1): 1-61, DOI: 10.11646/zootaxa.4771.1.1
Classification
- kingdom
- Animalia
- phylum
- Annelida
- class
- Polychaeta
- order
- Terebellida
- family
- Trichobranchidae
- genus
- Terebellides
- species
- Terebellides kirkegaardi
description
Description based on holotype Measurements and general body features. Complete specimen, 28.0 mm long and 2.5 mm wide (Fig. 21 A, 22 A−B); body tapering posteriorly with segments increasingly shorter and crowded towards pygidium. Prostomium compact; large tentacular membrane surrounding mouth, with typical buccal tentacles with expanded tips (Fig. 22 A−Β). SG 1 as an expanded structure below tentacular membrane (Fig. 22 A, 24 A). Lateral lappets and ovalshaped glandular region in TC 3 not present. Branchiae. Branchiae arising as single structure from SG 3, consisting of a single very long (about same length as dorsal posterior lobes) stalked mid-dorsal branch (Fig. 21 A, 22 A−D, 24 A), with one pair of dorsal (upper) un- fused lobes reaching TC 4 or TC 6 (if branchial stalk bent backwards); a pair of ventral (lower) lobes about as long as dorsal ones but thinner, not fused together and arising directly from stalk (Fig. 21 A, 22 A−D, 23 A, 24 A). Ante- rior projection of dorsal lobes (lobe 5) very well developed, about half length of posterior dorsal lobes (Fig. 21 A, 22 A−D, 23 A, 24 A). Pointed projection of posterior region of both upper and lower lobes much longer in ventral ones, becoming a terminal filament (Fig. 23 A). Both sides of branchial lamellae ciliated, arrangement in rows and / or tufts or papillae not seen. Thorax. Eighteen pairs of notopodia (SG 3 − 20); that of TC 1 shorter than subsequent ones (Fig. 24 A−B), with notochaetae as simple capillaries, shorter in number and length than following ones. Neuropodia as sessile pinnules, from TC 6 (SG 8) to pygidium, with uncini in single rows starting from TC 7 (SG 9) throughout. First neuropodia (TC 6) with 4 – 5 sharply bent, acute-tipped, geniculate chaetae (Fig. 23 B, 24 C−D) having minute teeth forming a very low marked capitium (Fig. 24 D). From TC 7, neuropodia with 11 – 17 uncini per torus in one row (Fig. 24 E) with long shafted denticulate hooks, rostrum about two times longer than capitium, with 2 − 5 big teeth above main fang, and surmounted by a crest of smaller denticles (Fig. 24 F−G). Abdomen. About 40 % of body length, with 31 pairs of neuropodia as erect pinnules with about 20 – 25 uncini per torus having four teeth above main fang surmounted by a crest of several teeth of same and / or smaller length (Fig. 23 D). Other features. Papilla on first thoracic notopodia not seen; button-hole-like pairs of dorsal nephridial openings on, at least, each SG 7 (TC 5) notopodium (Fig. 23 B−C); second pair not seen. Pygidium blunt, as funnel-like depression. Methyl green staining pattern. Anterior CH 1 to CH 3 solid; CH 4 to CH 9 striped; fading from CH 10 to CH 12; J-shaped glandular region marked lateral to CH 3; pattern 5 of Schüller & Hutchings (2010) (Fig. 37). Variations. Terebellides kirkegaardi sp. nov. is a medium-sized species (15 − 30 mm long). Eggs were visible in body cavity of females across all length range. Most specimens are in good conditions, with bodies and branchiae complete.
description
Figures 11 B, 21 A, 22 – 24, 37; Tables 1, 2 urn: lsid: zoobank. org: act: 82974 B 42 - 2924 - 48 A 8 - BD 1 A- 254 FED 0 F 881 B
diagnosis
Diagnosis. Body of medium / large size (15 – 30 mm in length). Branchiae with a long and thick stalk; anterior lobe large; posterior ventral lobes about as long as dorsal ones, with short terminal filaments, emerging directly from branchial stem. TC 1 notopodia and notochaetae shorter than following thoracic ones. Thoracic neurochaetae with rostrum / capitium length about 2 / 1, and capitium with a first row of 2 – 5 medium-sized teeth followed by progressively smaller ones.
discussion
Remarks. Terebellides kirkegaardi sp. nov. is mostly characterised by its long branchial stalk and well-developed anterior triangular lobe, coupled with a TC 1 notopodia shorter than following, and very low marked capitium teeth in TC 6 thoracic uncini (only detected with SEM). The branchial appearance is similar across most specimens studied (cfr. Fig. 21 A, 22 A – D, 24 A) — but see Fig. 22 E – F, 23 A — giving rise to a characteristic body profile that differs from any other known species of the genus. Terebellides kirkegaardi sp. nov. most closely resembles Terebellides canopus Schüller & Hutchings, 2013, Terebellides mira Schüller & Hutchings, 2013 (both from deep waters off South Western Atlantic Ocean), and Terebellides sepultura Garraffoni & Lana, 2003 (from Brazilian coasts). However, they lack the anterior projection of branchial lobes and posterior lobes are free from each other. Terebellides mira also bears a branchial stem that is much longer than the proper branchial lobes. Two specimens from Myanmar, identified as Terebellides cf. woolawa Hutchings & Peart, 2000 by Parapar et al. (2016 a), also show long branchial stems, but differ from T. kirkegaardi sp. nov. in having an even more developed, non-triangular anterior lobe, as well as smaller postero-ventral lobes. Furthermore, T. woolawa as described by Hutchings & Peart (2000) bears a similar anterior lobe, but the branchial stem is much shorter.
distribution
Distribution and bathymetry. Victoria (aka Limbé, Cameroon); 8 − 9 m depth (Fig. 11 B; Table 1).
etymology
Etymology. This species is named in honour of Danish researcher Jørgen Bagger Kirkegaard (1920 − 2006), who participated in the Galathea and Atlantide Deep Sea Expeditions. His 1958 publication on West African sedentary polychaetes included most of the specimens studied in the present work.
materials_examined
Material examined. Type material. Holotype (NHMD- 231439); paratypes: 37 specimens (NHMD- 636923 to NHMD- 636925), all from the same original vial as the holotype (Table 1).
materials_examined
Type locality. Cameroon; 8 – 9 m depth (Table 1).