Nothria josae, Paxton & Budaeva & Gunton, 2023

Paxton, Hannelore, Budaeva, Nataliya & Gunton, Laetitia M., 2023, Amazing Diversity of Nothria (Annelida, Onuphidae) in the Australian Deep Sea, Records of the Australian Museum (Rec. Aust. Mus.) 75 (3), pp. 215-247 : 230-232

Nothria josae sp. nov.

urn:lsid:zoobank.org:act:D8BEF1C4-7863-4808-8245-609D9DBABC7A

Figs 1 , 12–14 , Tables 2 , S 1

Nothria sp. nov. 3.— Gunton et al., 2021:76, fig 16F.

Holotype. Australian Museum ( AM) W.51343, IN2017 _ V03 _100; 9 Jun 2017; Australia, New South Wales, Byron Bay , 28.05– 28.10°S 154.08°E; 999–1013 m depth . Paratypes (5): AM W.49935, IN2017 _ V03 _100 (1); AM W.49937, IN2017 _ V03 _100 (1); AM W.51344, IN2017 _ V03 _100 (1); AM W.51345, IN2017 _ V03 _100 (1); AM W.51445, IN2017 _ V03 _121 (1 mounted on SEM pin).

Other material examined (31). AM W.49936, IN 2017_ V 03_100 (25); AM W.49934, IN 2017_ V 03_121 (2); AM W.51449, IN 2017_ V 03_121 (3 in tubes); AM W.53850. IN 2017_ V 03_121 (1).

Diagnosis. Large posterior eyes present; antennae extending to chaetiger 7–11; branchiae short digitate filaments, from chaetiger 11–13; 3 first chaetigers with anterior hooks: slender, bidentate simple and pseudocompound hooks on chaetiger 1; slender bidentate pseudocompound hooks on chaetiger 2 and very slender bidentate pseudocompound to compound hooks on chaetiger 3; pectinate and limbate chaetae from chaetiger 3; subacicular hooks from chaetiger 9–12.

Description. All specimens lacking posterior ends. Length of holotype 5.5 mm for 13 chaetigers, width 1.5 mm; paratypes 4.5–15 mm (12–30 chaetigers) long, 1.5–2.0 mm wide. Non-type material ranging from 1.0– 1.8 mm in width. Alcohol-stored specimens overall whitish to cream-coloured. Few specimens with pale brown median spot on prostomium, pale brown splotches on first parapodia and on ventral upper and lower lips; holotype and most other specimens without any pigmentation. Subdermal brown pigment or blood in jaw region, sometimes visible through epidermis dorsally. Prostomium subtriangular, wider than long, with 2 closely spaced ovoid frontal lips ( Fig. 12A,B ). Palpo- and antennophores with 2–3 proximal rings and longer distal ring ( Fig. 12A ). Palpostyles tapering, extending to chaetiger 1, antennostyles tapering gradually, lateral antennostyles extending to chaetiger 9 (7–9), median antennostyle noticeably thicker than laterals ( Fig. 12A ), extending to chaetiger 11 (9–10). Nuchal grooves straight, with small middorsal separation. Large posterior pair of eyes at bases of lateral antennae, faded in holotype but darkly pigmented in paratypes and other specimens. Ventral upper lips rounded, lower lips subtriangular, neither with median section ( Fig. 12B ). Peristomium short, peristomial cirri inserted subdistally on peristomium, about twice as long as peristomium ( Fig. 12A ).

First chaetiger enlarged, about twice as long as peristomium, chaetiger 2 much shorter, chaetiger 3 similar in length to following ones. Anterior three pairs of parapodia modified ( Fig. 12A,B ). First pair greatly enlarged, directed forward, extending well beyond prostomium, with large auricular prechaetal lobes, subulate postchaetal lobes, dorsal and ventral cirri ( Fig. 12A,B ). Parapodia 2 similar but smaller, with smaller prechaetal, digitate postchaetal lobes and subulate ventral cirri ( Fig. 12A,B ). Parapodia 3 only slightly larger than subsequent ones ( Fig. 12A,B ), directed anterolaterally, with tongue-like prechaetal lobes ( Fig. 12C ). From chaetiger 4 onwards parapodial structures becoming more uniform; prechaetal lobes continued into posterior region, last postchaetal lobes on chaetiger 14 (13–16). Dorsal cirri long and slender to chaetiger 10–12, thereafter becoming gradually shorter, by chaetiger 30 reduced to tiny stumps. Ventral cirri transitional on chaetiger 3, replaced by glandular pads from chaetiger 4 ( Fig. 12B ). Branchiae beginning on chaetiger 11 (11–13, most often 12) as little stump, becoming short digitate filament ( Fig. 12D ) by chaetiger 15–17, continuing as tiny stump to end of incomplete specimens.

First pair of parapodia with 2 bidentate almost slender simple hooded hooks ( Figs 12E , 13A ) and 1 slender bidentate pseudocompound ( Fig. 13B ) hook. Parapodia 2 with 3 slender simple to pseudocompound ( Fig. 13C ) bidentate hooks. Parapodia 3 ( Fig. 12C ) with 2–4 upper limbate chaetae, about 20–30 scoop-shaped pectinate chaetae with 18–20 teeth, 2–3 very slender bidentate pseudocompound to compound hooks with serrated upper shafts and appendages ( Fig. 13D ). Following parapodia ( Fig. 12D ) with 5–6 upper limbate, several pectinate and lower limbate chaetae; subacicular hook present singly from chaetiger 12 (9–12) and as pairs from chaetiger 15 (12–16). Pygidium unknown.

Mandibles ( Fig. 13E ) highly calcified, white, except for darkly sclerotized protomandibles; shafts long and slender, cutting plates high with pronounced median and large distal tooth. Maxillae ( Fig. 13F ) overall beige coloured, fangs and teeth brown, ligaments and attachment lamellae more sclerotized, appearing dark brown. Maxillary formula (based on 3 paratypes): MI = 1+1; MII = 6–7 + 7–8 (left most distal tooth fang-like); MIII = 7–8 + 0; MIV = 6–7 + 8–10; MV = 1+1. Ratio of mandibles/maxillae = 1.2. Flattened tube, lining transparent, covered on outside with different sized shell fragments (some much larger than diameter of tube), lateral spaces between shells filled in with small particles ( Fig. 14A ).

Remarks. Below we describe a sister species to N. josae sp. nov., where morphological similarities and differences between the two species will be discussed.

Etymology. Nothria josae sp. nov. is named for Josie Paxton, granddaughter of the first author.

Distribution. The new species was collected from the Coral Sea Marine Park, Queensland and off Byron Bay, New South Wales, in 999–1013 m and the Coral Sea Marine Park in 1013–1093 m depth ( Fig. 14B ).

Figures

Figure 1. Consensus tree from the Bayesian analysis of the combined COI, 16S and 28S dataset; numbers on nodes indicate Bayesian posterior probabilities; capital letters correspond with the clades discussed in the text.Species delimitation results inferred by morphology and DNA-based methods (COI, 16S, and 28S) are indicated right to the consensus tree followed by the final hypothesis based on all evidence combined. White bars indicate missing data.

Figure 12. Nothria josae sp. nov. SEM micrographs of paratypeAM W.51445. (A) anterior part, dorsal view; (B) same, ventral view; (C) parapodium of chaetiger 3, dorsal view; (D) parapodium of chaetiger 14, dorsal view; (E) slender bidentate simple hook from chaetiger 1.

Figure 13. Nothria josae sp. nov. Line drawings of AM W.49934. (A) slender bidentate simple hook from chaetiger 1; (B) very slender bidentate pseudocompound hook from same; (C) very slender bidentate pseudocompound hook from chaetiger 2; (D) bidentate serrated compound hook from chaetiger 3; (E) mandibles; (F) maxillae.

Figure 14. Nothria josae sp. nov. (A) photograph of tube AM W.51449; (B) map of distribution; red dot represents type locality, green dot other site of collection.