Terebellides simonae, Lavesque & Hutchings, 2025

Terebellides simonae sp. nov.

zoobank.org:act: E84D8A02-F280-441B-9D39-563CA0FFB9AF

Figures 6 View FIGURE 6 and 7 View FIGURE 7

Material examined. Holotype. SAMC-A075877 , South East Atlantic , South Africa, Western Cape, False Bay , 34.35°S, 18.678°E, October 1967 GoogleMaps . Paratypes. SAMC-A097162 , South East Atlantic , South Africa, Western Cape, False Bay , 34.35°S, 18.678°E, October 1967, mounted for SEM GoogleMaps .

Description. Small-size species, holotype 19.0 mm long and 1.9 mm wide. Body tapering posteriorly, segments increasingly shorter and more compacted towards pygidium. Preserved specimens whitish.

Prostomium compact; eyespots absent; large upper lip surrounding mouth; most of buccal tentacles lost, only remaining short uniformly cylindrical ones ( Figs 6B–D View FIGURE 6 ; 7A–C View FIGURE 7 ). Lower lip expanded below upper lip ( Fig. 6A–B View FIGURE 6 ). SGs I and II only visible ventrally; following segments with lobes as ventral collars, lateral lappets on SG IV–VIII (TC 2–6) continuing ventrally; dorsal rounded projections on TC 1–TC 3; presence of glandular large oval lateral region on SG V (TC 3) ( Figs 6A–B View FIGURE 6 ; 7A, C View FIGURE 7 ).

Branchiae arising as a single structure from SG III, reaching SG IX, as single elongate and annulated mid-dorsal stalk, with two pairs of lobes, almost free from each other, lower pair thinner; anterior branchial projection (5 th lobe) present. Dorsal lobes with about 50 packed lamellae; papillar projections on margins only on most anterior lamellae and ciliated tufts present; dorsal and ventral lobes terminating with filaments ( Figs 6 View FIGURE 6 ; 7A–B, D View FIGURE 7 ).

Eighteen pairs of thoracic notopodia (SG III–XX), two first pairs reduced, notochaetae from TC 1 (SG III) about same size (or slightly longer) as those from subsequent notopodia. All notochaetae simple capillaries, arranged in two rows, anterior row shorter. Neuropodia as sessile pinnules from TC 6 (SG VIII) to pygidium. First thoracic pair of neuropodia (TC 6) with 4–5 sharply bent geniculate chaetae, with acute tips ( Fig. 7C View FIGURE 7 ), subsequent thoracic neuropodia (from TC 7) with about 8–10 uncini per torus arranged in irregular row, rostrum vs. capitium length ratio RvC =1/0.4, three mid-sized teeth above main fang surmounted by two rows of short denticles and upper crest of several minute denticles ( Fig. 7E View FIGURE 7 ); about 30–35 pairs of abdominal neuropodia, as erect paddle-shaped pinnules, each with about 15 uncini present at margin; RvC=1/0.9, four teeth above main fang, surmounted by row of 4–5 short teeth and two rows of shorter denticles ( Fig. 7F View FIGURE 7 ).

Two pairs of globular nephridial papillae posterior to base of notopodia of SG VI–VII (TC 4–TC 5). Pygidium rounded.

Methyl Green staining pattern: the first 10 segments stain solid; striped from SG XI to about SG XV; GLR stained with a dark blue anterior margin.

Etymology. This species is dedicated to Carol Simon, senior taxonomist at Stellenbosch University for her contribution to the knowledge of South African polychaetes and her friendship.

Habitat. Coastal.

Type locality. South Africa, Western Cape, False Bay .

Distribution. Known from type locality only.

Remarks. Before Parapar et al. (2020a), only Terebellides stroemii Sars, 1835 and T. stroemii var. africana (now T. africana Augener, 1918 ) had been recorded in Africa. The first one, described from Norway, was known to be a cosmopolitan species, but we now know that this species is restricted to northern Europe ( Parapar & Hutchings 2014; Lavesque et al. 2019b; Parapar et al. 2020b). With the description of seven new species, Parapar et al. (2020a) greatly increased the diversity of this genus along the African coasts. However, with the exception of T. augeneri and Terebellides sp. 2 from South Africa ( Parapar et al. 2020a), all the other species have been described from equatorial region of western Africa.

Terebellides simonae sp. nov. differs from T. augeneri by the presence of dorsal rounded projection on the first three chaetigers and a large glandular lateral region, which are both absent for T. augeneri . The branchial lobes of T. simonae sp. nov. have filamentous tips while those of T. augeneri have pointed projections. A fifth branchial lobe is present on T. simonae sp. nov. and absent on T. augeneri . Finally, T. augeneri has no branchial papillae on the lamellae while they are present anteriorly in T. simonae sp. nov.

Terebellides simonae sp. nov. differs from Terebellides talboti sp. nov. (see below) by the presence of dorsal rounded projection on the first three chaetigers and a large glandular lateral region, which are both absent for Terebellides talboti sp. nov. Terebellides simonae sp. nov. differs also by the fusion of branchial lobes at least on 50 % of their length while these lobes are free for T. talboti sp. nov. Finally, the branchial lobes of T. simonae sp. nov. end by filamentous tips while those of Terebellides talboti sp. nov. end with pointed projections.

Terebellides simonae sp. nov. differs from Terebellides sp. 2 by the color pattern of the anterior chaetigers. Indeed, this last species is characterised by the presence of white ventral coloration on the first five chaetigers, which is not the case for Terebellides simonae sp. nov.

Among the other West African species of Terebellides , and with the presence of a glandular lateral region and a fifth branchial lobe, T. simonae sp. nov. is similar with T. congolanus Parapar, Martin & Moreira, 2020 and T. kirkegaardi Parapar, Martin & Moreira, 2020 . Terebellides simonae n. sp differs from T. congolanus by the presence of free branchial lobes with filamentous tips, while they are fused on 50 % on their length and have posterior projections for T. congolanus . Moreover, T. congolanus has the first thoracic chaetiger and its notochaetae are more developed than the subsequent ones, which is not the case for T. simonae sp. nov. Terebellides simonae sp. nov. differs from T. kirkegaardi by the presence of dorsal projections on the first three chaetigers and the presence of papillar projections on margins of branchial lamellae, while these projections and papillae are absent for T. kirkegaardi . Unlike T. simonae sp. nov., T. kirkegaardi has first thoracic chaetiger and its notochaetae shorter than the subsequent ones.