Macellicephalinae gen. sp. 5

Gunton, Laetitia M., Kupriyanova, Elena K., Alvestad, Tom, Avery, Lynda, Blake, James A., Biriukova, Olga, Boeggemann, Markus, Borisova, Polina, Budaeva, Nataliya, Burghardt, Ingo, Capa, Maria, Georgieva, Magdalena N., Glasby, Christopher J., Hsueh, Pan-Wen, Hutchings, Pat, Jimi, Naoto, Kongsrud, Jon A., Langeneck, Joachim, Meissner, Karin, Murray, Anna, Nikolic, Mark, Paxton, Hannelore, Ramos, Dino, Schulze, Anja, Sobczyk, Robert, Watson, Charlotte, Wiklund, Helena, Wilson, Robin S., Zhadan, Anna & Zhang, Jinghuai, 2021, Annelids of the eastern Australian abyss collected by the 2017 RV ' Investigator' voyage, ZooKeys 1020, pp. 1-198 : 1

Macellicephalinae gen. sp. 5 Fig. 23C

Diagnosis.

Large bodied specimen, complete, 33 mm long, 13 mm wide (including parapodia) for 26 segments. Facial tubercle present. Pharynx not everted, but jaws observed via dissection: two pairs of triangular jaws with four or five teeth per jaw; unknown number of pharyngeal papillae. Prostomium bilobed, lobes rounded anteriorly, and posteriorly, median antenna missing or absent, lateral antennae and frontal filaments absent, eyes absent. Palps smooth, short, with reduced palpophores. Tentacular segment fused to prostomium, with tentaculophores situated lateral to palps, both dorsal and ventral styles similar in length and form to palps, achaetous. Large dorsal papillated swollen structures present on (non-elytrigerous) segments 6, 8, 10, located between dorsum and base of cirrophores, possibly reproductive. Dorsal cirri long, longer than parapodia; ventral cirri on segment 2 larger than following segments, becoming small and filiform from segment 3 to posterior segments, inserted subdistally on neuropodia. Parapodia with notopodia reduced to small elongate acicular lobe on anterior face, with slender notochaetae emerging basally, chaetae with rows of fine spines and filiform tips; neuropodia large with elongate pre-chaetal lobe and rounded postchaetal bract-like lobe, neurochaetae much more stout than notochaetae, golden, lanceolate with rows of spines along two sides. Only six pairs of elytrophores distinct, on segments 2, 4, 5, 7, 9, and 11; thereafter difficult to discern due to swollen dorsal bases of parapodia. Pair of thick elytra present on first chaetiger (segment 2), elongate-reniform, covering dorsum, with some dark pigment spots and small marginal papillae; a single large elytra present on segment 11, thin, translucent, round to oval, without pigment or marginal papillae, not covering dorsum. Dorsal tubercles large, and from segment 12, basal swellings present dorsally on every parapodium, with two pairs of ridges running anteriorly and posteriorly along parapodium from dorsum towards dorsal cirrus; these swollen bases also papillated from segment 21. Ventral keel absent. Pygidium rounded, anus dorsal.

Remarks.

Due to the lack of lateral antennae, this specimen is assigned to Macellicephalinae , but does not appear to bear resemblance to any of the 37 currently valid Macellicephalinae genera ( Read and Fauchald 2020), due to the combination of the form of the neuropodial lobes and notopodial lobes, lack of branchiae, ridged and swollen dorsal tubercles (similar to those of Lepidonotopodium spp. but otherwise dissimilar to that genus), lack of frontal filaments, and the presence of serrated jaws.

Records.

1 specimen. Suppl. material 1: op. 79 (AM).

Figures

Figure 23. Polynoidae 2 A Harmothoe sp. 5 anterior end, dorsal view, and elytra (AM W. 52581) B Lepidasthenia indet. dorsal view, pharynx extended (AM W. 51580) C Macellicephalinae sp. 5 anterior end, dorsal view (AM W. 52014) D Polaruschakov sp. dorsal view (AM W. 52580). Scale bars: 5 mm.