Terebellides kirkegaardi

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), pp. 1-61: 29-33

publication ID

https://doi.org/10.11646/zootaxa.4771.1.1

publication LSID

lsid:zoobank.org:pub:A46FAF72-6F95-4DA3-A41D-FE770D6EDF1F

DOI

http://doi.org/10.5281/zenodo.3816163

persistent identifier

http://treatment.plazi.org/id/03BF4239-FFE9-FFE9-EAF8-C41B99CEFC54

treatment provided by

Plazi

scientific name

Terebellides kirkegaardi
status

sp. nov.

Terebellides kirkegaardi  sp. nov.

Figures 11BView FIGURE 11, 21AView FIGURE 21, 22–24View FIGURE 22View FIGURE 23View FIGURE 24, 37View FIGURE 37; Tables 1, 2

urn:lsid:zoobank.org:act:82974B42-2924-48A8-BD1A-254FED0F881B

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).

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. TC1 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.

Description based on holotype

Measurements and general body features. Complete specimen, 28.0 mm long and 2.5 mm wide ( Fig. 21AView FIGURE 21, 22View FIGURE 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. 22View FIGURE 22 A−Β). SG1 as an expanded structure below tentacular membrane ( Fig. 22AView FIGURE 22, 24AView FIGURE 24). Lateral lappets and ovalshaped glandular region in TC3 not present.

Branchiae. Branchiae arising as single structure from SG3, consisting of a single very long (about same length as dorsal posterior lobes) stalked mid-dorsal branch ( Fig. 21AView FIGURE 21, 22View FIGURE 22 A−D, 24A), with one pair of dorsal (upper) un- fused lobes reaching TC4 or TC6 (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. 21AView FIGURE 21, 22View FIGURE 22 A−D, 23A, 24A). Ante- rior projection of dorsal lobes (lobe 5) very well developed, about half length of posterior dorsal lobes ( Fig. 21AView FIGURE 21, 22View FIGURE 22 A−D, 23A, 24A). Pointed projection of posterior region of both upper and lower lobes much longer in ventral ones, becoming a terminal filament ( Fig. 23AView FIGURE 23). Both sides of branchial lamellae ciliated, arrangement in rows and/ or tufts or papillae not seen.

Thorax. Eighteen pairs of notopodia (SG3−20); that of TC1 shorter than subsequent ones ( Fig. 24View FIGURE 24 A−B), with notochaetae as simple capillaries, shorter in number and length than following ones. Neuropodia as sessile pinnules, from TC6 (SG8) to pygidium, with uncini in single rows starting from TC7 (SG9) throughout. First neuropodia (TC6) with 4–5 sharply bent, acute-tipped, geniculate chaetae ( Fig. 23BView FIGURE 23, 24View FIGURE 24 C−D) having minute teeth forming a very low marked capitium ( Fig. 24DView FIGURE 24). From TC7, neuropodia with 11–17 uncini per torus in one row ( Fig. 24EView FIGURE 24) 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. 24View FIGURE 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. 23DView FIGURE 23).

Other features. Papilla on first thoracic notopodia not seen; button-hole-like pairs of dorsal nephridial openings on, at least, each SG7 (TC5) notopodium ( Fig. 23View FIGURE 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. 37View FIGURE 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.

Type locality. Cameroon; 8–9 m depth (Table 1)  .

Distribution and bathymetry. Victoria (aka Limbé, Cameroon); 8−9 m depth ( Fig. 11BView FIGURE 11; Table 1).

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.

Remarks. Terebellides kirkegaardi  sp. nov. is mostly characterised by its long branchial stalk and well-developed anterior triangular lobe, coupled with a TC1 notopodia shorter than following, and very low marked capitium teeth in TC6 thoracic uncini (only detected with SEM). The branchial appearance is similar across most specimens studied (cfr. Fig. 21AView FIGURE 21, 22View FIGURE 22 A–D, 24A)—but see Fig. 22View FIGURE 22 E–F, 23A—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. (2016a), 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.