Neanthes cf. bassi Wilson, 1984

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

Neanthes cf. bassi Wilson, 1984

Diagnosis.

Area I = 0-4; II = 6-27; III = 1-14; IV = 1-18 conical paragnaths + 2-7 smooth bars; V = 0-1; VI = 2-16; VII-VIII = 5-30. Dorsal notopodial ligule similar size to acicular ligule throughout (not markedly reduced or expanded on posterior chaetigers). Prechaetal notopodial lobe absent. Neuropodial postchaetal lobe present on chaetigers 1- ~ 12. Ventral neuropodial ligule on posterior chaetigers reduced, up to half length of acicular neuropodial ligule. Notochaetae homogomph spinigers only (homogomph falcigers absent). Neuropodial dorsal fascicle fused falcigers absent.

Remarks.

Prior to the collection of the first abyssal samples in Australian waters, Neanthes bassi was only known from 0-147 m. The most similar species is Neanthes tasmani Bakken, 2002 (known from slightly deeper locations, 75-220 m). However, Neanthes specimens from this study and recent GAB voyages are very close to N. bassi , yet they have been recorded from 200-4800 m. This taxon is referred to here as Neanthes cf. bassi , a hypothesis to be tested when molecular data are available. Two species other than N. tasmani are similar enough to be confused with N. bassi (until the pharynx is dissected), Neanthes kerguelensis (which has fewer maxillary ring paragnaths and lacks oral ring paragnaths or has at most VI = 1 and VII-VIII = 8) and Nicon maculata (which is also described here and lacks paragnaths completely yet is otherwise strikingly similar to N. kerguelensis ).

This species was also recorded from eight stations (199-4518 m) in the GAB ( MacIntosh et al. 2018: additional file 2).

Records.

15 specimens. Suppl. material 1: ops. 15, 30, 32, 43, 65 (AM).