Ophryotrocha hanneloreae, Georgieva & Wiklund & Ramos & Neal & Glasby & Gunton, 2023

Georgieva, Magdalena N., Wiklund, Helena, Ramos, Dino A., Neal, Lenka, Glasby, Christopher J. & Gunton, Laetitia M., 2023, The Annelid Community of a Natural Deep-sea Whale Fall off Eastern Australia, Records of the Australian Museum (Rec. Aust. Mus.) 75 (3), pp. 167-213 : 177

Ophryotrocha hanneloreae sp. nov.

urn:lsid:zoobank.org:act:875C94C2-FCFD-432B-96FB-6C9A053ADE04

Fig. 9

Holotype: AM W.53697 (body length 1.3 mm for 20 chaetigerous segments), IN2017_V03_100; 9 June 2017; off Byron Bay , NSW, Australia, beam trawl, start: 28.05°S 154.08°E, 999 m, end: 28.10°S 154.08°E, 1013 m . Paratypes: NMV F296819–296821 , NHMUKANEA 2022.775 – 777 , samelocalityas holotype. DNA vouchers: AMW.53695–53696 , samelocalityas holotype .

Description. Body length upto 3 mm for examined, complete specimens. Body compressed dorsoventrally, anterior body with similar width from head to mid-body, then tapering towards pygidium ( Fig. 9A ). Head rounded with simple antennae, approximately equal length to palpostyles. Biarticulated palps, palpophores large, equal length to palpostyles ( Fig. 9A ). Mandibles forked without dentition, inner peak larger than outer peak ( Fig. 9B ). Maxillae P-type with a pair of forceps and seven pairs of free denticles (D1–7). Forcepswithcoarse teethincreasing in size from base to tip, D1–3 with progressively slightly finer teeth, D3 with a larger distal fang. Denticles 4–7 with fine evenly sized teeth ( Fig. 9B, 9C ). Two peristomial achaetous segments, the first twice as long as the second ( Fig. 9A ). Parapodia uniramous with short distal dorsal cirri, without ventral cirri ( Fig. 9D ).

Supra-acicular chaetae simple ( Fig. 9E ), sub-acicular chaetae compound with short blades ( Fig. 9F ), sub-acicular lobe with simple chaeta.

Pygidium with terminal anus, two lateral cirri and a midventral stylus.

Distribution. IN2017_V03, Station 100. Pilot whale carcass, off Byron Bay, New South Wales, Australia in 999–1013 m.

Etymology. This species is named in honour of Dr Hannelore Paxton at Macquarie University, Australia, for her comprehensive work with Ophryotrocha worms, and for sharing her expertise especially regarding the jaw morphology of eunicids.

Remarks. The new species is morphologically most similar to Ophryotrochalongicollaris Wiklund et al., 2012 . The two species differ in shape of parapodia where the new species has largerdorsal cirri, shorter anal cirri, and P-typemaxillae while O. longicollaris has only been reported having K-type maxillae. In the phylogenetic tree ( Fig. 8 ), this species does not occur near O. longicollaris , but instead is recovered in an unresolved position in a large clade containing the type species of the genus. The single gene 16S maynotbe enough to resolve the position.

Figures

Figure 8. Phylogeny of the Ophryotrocha genus based on Bayesian analysis of the 16S gene. Numbersadjacent to nodes indicateposterior probabilities, and taxa for which sequences have been contributed by the present study are indicated in bold. GenBank accession numbers are given after taxa names for the GenBank sequences.

Figure 9. Ophryotrocha hanneloreae sp. nov. (A) Photo of holotype, dorsal side, holotype 1.3 mm long; (B) anterior end with jaws, scale bar is 25 μm; (C) details of maxillae elements with mandible shafts, scale bar is 50 μm; (D) parapodium, scale bar is 50 μm; (E) supra-acicular simple chaeta, scale bar is 50 μm; (F) sub-acicular compound falcigerous chaeta, scale bar is 50 μm.