Bruunilla nealae, Bonifácio & Menot, 2019

Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), Zoological Journal of the Linnean Society 185, pp. 555-635 : 595-597

BRUUNILLA NEALAE SP. NOV.

( FIG. 11A–G; TABLES 1, 2)

Type material: Holotype, MNHN-IA-TYPE 1824 ( IFR512 ), complete, length 3.00 mm, width 0.69 mm, 17 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, Ifremer license area, station 171, collected 17 April 2015, epibenthic sledge supra-net, start 14°2.687′N, 130°5.951′W, end 14°3.205′N, 130°4.606′W, 5024– 5017 m depth, 2979 m trawling distance.

Description (based on holotype): Holotype complete, 3.00 mm long and 0.69 mm wide for 17 segments (including tentacular segment), dorsoventrally flattened, slightly tapering posteriorly; live specimen pale white, slightly translucent; ethanol-preserved specimen pale yellow.

Prostomium bilobed, wider than long, lobes not pronounced, anteriorly rounded; with short, ovoid frontal filaments; median notch between prostomial lobes narrow and shallow ( Fig. 11A); eyes absent. Median antenna present, lateral antennae absent; ceratophore of median antenna bulbous, very short (shorter than anterior end of frontal filaments), inserted near posterior margin of prostomium; style smooth, tapering, long (reaching segment 7). Palps smooth, tapering, short (reaching segment 4; Fig. 11A). Facial tubercle not seen. A pair of wing-like structures on ventral side, like a prolongation of lower lip, separated longitudinally until segment 3; median notch between lobes narrow and deep; each lobe oval, with blunt tips, with most longitudinal folds anteriorly, and most horizontal folds posteriorly, partially covering first four or five segments ( Fig. 11B, G).

Tentacular segment with a pair of short lobes, inserted laterally and slightly below prostomium; without acicula or chaetae; tentaculophores small, cylindrical, equal sized; tentacular styles smooth, tapering, dorsal tentacular style (reaching segment 7) slightly longer than ventral tentacular cirri ( Fig. 11A). Pharynx not everted. Second segment with elytrophores, subbiramous parapodia, with chaetae and ventral cirri.

Eight pairs of knob-like, bulbous elytrophores on segments 2, 4, 5, 7, 9, 11, 13 and 15 (elytron still attached on segment 2, both sides and on segment 4, on the left side); elytra in poor condition, thin, fragile, translucent, surface and margin smooth.

Cirrigerous segments with distinct, small dorsal cirrophores, inserted subdistally on notopodia; styles smooth, tapering, long (as long as the neuropodial lobe), longest on segments 3 and 14 (much longer than tip of neuroacicular lobe); dorsal tubercles absent.

Ventral cirri smooth, tapering, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style smooth, tapering, long (much longer than tip of neuroacicular lobe); in subsequent segments inserted subdistally on neuropodia ( Fig. 11C), styles long (about as long as tip of neuroacicular lobe).

Parapodia subbiramous, notopodia reduced, much shorter than neuropodia ( Fig. 11C). Notopodia reduced, subtriangular, tapering into long acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, rectangular to subtriangular, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis; posteriorly post-chaetal lobe becoming ventrally pointed; segments 11–14 with long (slightly shorter than tip of neuroacicular lobe) cirriform neuropodial papilla present, inserted in upper part of neuropodia lobe, smooth, tapering, long, blunt tips. Notochaetae few (one to six observed), short to long, slender, distally flattened to concave, serrated along both sides, with blunt tips ( Fig. 11D); notochaetae more slender than neurochaetae. Neurochaetae moderate in number (16 observed), long to short, with distal part flattened to concave, serrated along both margins, with pointed tips ( Fig. 11E, F); upper group stouter, longer than lower group ( Fig. 11F).

Nephridial papillae absent. Pygidium small, rounded, enclosed by last segment; with dorsal anus. Anal cirri lost, scars not seen.

Remarks: Bruunilla natalensis is the only species described in this genus until now. Bruunilla nealae sp. nov. is unique in having frontal filaments and long neuropodial papillae on segments 11–14, which are absent in Bruunilla natalensis (papilla maybe present on segment 7; see Remarks on Bruunilla ). In addition, the blunt tips of the wing-like structure in Bruunilla nealae sp. nov. differ from the protruding tips of the wing-like structure in Bruunilla natalensis . Furthermore, the average K2P distance between Bruunilla nealae sp. nov. and Bruunilla sp. 692 was very high (27.3% for 16S).

Etymology: This species is dedicated to Lenka Neal (Natural History Museum, London) for her friendship, discussion and comments during this project.

Genetic data: Gene sequencing for this species was successful for 16S and 18S (only 1200 bp) but not for COI.

Distribution: Only one specimen was sampled at a single station within the Clarion-Clipperton Fracture Zone in Ifremer license area (type locality).