Nothria lizae, 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 : 232-235

Nothria lizae sp. nov.

urn:lsid:zoobank.org:act:189B36FF-006D-426D-8E85-50540F80784A

Figs 1 , 15–17 , Tables 2 , S 1

Holotype. Australian Museum ( AM) W. 49032, IN2015 _ E02_22; 11 Apr 2015; Australia, Tasmania, Huon Marine Park , 44.32°S 147.32– 147.31°E; 2010 m depth . Paratypes (8): AM W.49034, IN2015 _E02_21 (1). AM W.49035, IN2015 _E02_21 (1). AM W.51446, IN2015 _ E02_22 (1 SEM on pin). SAMA E8971 , IN2015 _C01_69 (1). AM W.51566, IN2018 _ V06 _74 (1). AM W.51632, IN2018 _ V06 _169 (1). AM W.51633, IN2018 _ V06 _169 (1). AM W.51634, IN2018 _ V06 _169 (1).

Other material examined (102). AM W.53854, IN 2015_ E0_21 (2). AM W.53855, IN 2015_E0_22 (1). AM W.53853, IN 2015_E0_22 (2). AM W.51565, IN 2018_VO6_037 (1). AM W.53856, IN 2018_ V 06_ 169 (2). AM W.53857, IN 2018_ V 06_169 (94).

Diagnosis. Eyes absent; antennae extending to chaetiger 9–18; short branchiae from chaetiger 12–14 onwards on some or all chaetigers; first 3 chaetigers with anterior hooks: robust, bidentate simple and slender pseudocompound hooks on chaetiger 1; slender bidentate simple and pseudocompound hooks on chaetiger 2; bidentate pseudocompound to compound hooks on chaetiger 3; pectinate and limbate chaetae from chaetiger 3; subacicular hooks from chaetiger 10–13.

Description. Holotype almost complete, measuring 20 mm for 42 chaetigers, width 2.8 mm; 3 complete paratypes (16–30 mm long for 48–57 chaetigers, width 2.6–4.0 mm); 5 incomplete paratypes (7–19 mm long for 15–39 chaetigers, width 2.2–3.0 mm). Non-type material ranging from 1.9–3.0 mm in width. Alcohol-stored specimens overall whitish to cream coloured with brown splotches on head structures, parapodia and dorsum. Prostomium anteriorly rounded, wider than long with 2 ovate frontal lips close together in holotype and most specimens but separated in some by small space. Palpo- and antennophores with 2–3 proximal rings and a slightly longer distal ring ( Fig. 15A,B ). Palpostyles tapering, extending to chaetiger 1, lateral antennostyles to chaetiger 10 (9–14), median antennostyle to 12 (11–18); antennostyles tapering gradually, ending in blunt tips. Nuchal grooves straight, with small middorsal separation. Eyes absent. Ventral upper lip rounded to oval, lower lip subtriangular, neither with median section. Peristomium short, peristomial cirri inserted subdistally on peristomium, about twice as long as peristomium ( Fig. 15A ).

First chaetiger enlarged, slightly more than twice as long as peristomium, chaetiger 2 about half as long as chaetiger 1, chaetiger 3 similar in length to following ones. Anterior 3 pairs of parapodia modified; first pair greatly enlarged, directed forward, extending far beyond anterior margin of prostomium with large auricular prechaetal lobes, subulate postchaetal lobes, digitate dorsal and subulate ventral cirri ( Fig. 15A,B ). Prechaetal lobes of holotype and most paratypes with small lip-like extension between two large hooks ( Fig. 15C ). Second pair of parapodia similar to first but smaller, with smaller prechaetal lobes. Third pair only slightly larger than subsequent parapodia, with further reduced, tongue-like prechaetal lobes; ventral cirri ovate, transitioning to glandular pads ( Fig. 15A,B ). From chaetiger 4 onwards parapodial structures becoming more uniform; dorsal cirri gradually becoming thinner and shorter, prechaetal lobes becoming short and rounded, postchaetal lobes gradually decreasing in length, last one on chaetiger 14 (13–15), ventral cirri replaced by oval glandular pads. Branchiae present as short, filaments; in holotype tiny branchia from chaetiger 12, increasing slightly to chaetiger 30 where it is equal in length to greatly reduced dorsal cirrus, then decreasing in size but present until end of fragment. In paratypes branchial filament starting from chaetiger 12–14 ( Fig. 15D ), sometimes only for a few segments, thereafter absent or later reappearing again to near end of body.

First pair of parapodia with 2 almost robust (shaft <30 µm wide) ( Fig. 15E ) to robust bidentate simple ( Fig. 16A ) and 1 slender bidentate pseudocompound hooded hook ( Fig. 16B ). Second pair of parapodia with slender, bidentate simple ( Fig. 16C ) and pseudocompound hooks ( Fig. 16D ). Third pair of parapodia with 3–4 very slender pseudocompound to compound bidentate hooks with serrated upper shaft and appendages ( Fig. 16E ), as well as 2–3 limbate chaetae and numerous (about 30) scoop-shaped pectinate chaetae with about 20–22 teeth. Anterior hooks absent from chaetiger 4, limbate and pectinate chaetae present in reduced numbers to end of body. Subacicular hooks present singly from chaetiger 12 (10–13) and as pairs from chaetiger 14 (12–15). Pygidium with 2 long anal cirri.

Mandibles ( Fig. 16F ) highly calcified, almost white, except for darkly sclerotized protomandibles; shafts long and slender, cutting plates high with weakly defined lower teeth and large distal tooth. Maxillae ( Fig. 16G ) overall light brown with darker sclerotized teeth and attachment lamellae; maxillary formula: MI = 1+1; MII = 7–10 + 9–10 (left most distal tooth fang-like), MIII = 7–8 + 0; MIV = 1+1 (based on 5 specimens). Ratio of mandibles/maxillae = 1.2. Flattened tube ( Fig. 17A ), covered mainly with evenly sized shell fragments dorsally and ventrally giving the appearance of a pavement, sides filled in with foraminiferans; lining transparent .

Remarks. Nothria lizae sp. nov. and N. josae sp. nov. (described directly above) are two sister species that are similar morphologically ( Table 2 ). They both have short branchiae from about chaetiger 12–13, a similar distribution of bidentate simple and pseudocompound hooks on chaetigers 1–3, pectinate chaetae from chaetiger 3 and subacicular hooks from about chaetiger 12. However, they can be distinguished in that N. josae sp. nov. is a smaller species (maximum width to 2 mm), has a subtriangular prostomium, large posterior eyes, shorter antennae (median to chaetiger 9–11), tube with oversized shells, and was collected at a depth of about 1000 m, while N. lizae sp. nov. has a rounded prostomium, lacks eyes, has longer antennae (median to chaetiger 11–18), tube with evenly sized shell fragments and occurs at about 1500–2000 m depth.

Etymology. Nothria lizae sp. nov. is named for Liza Paxton, granddaughter of the first author.

Distribution. The new species has been collected south of Tasmania in the flat area south of Brians, in 1443– 1422 m, the Huon Marine Park in 2010–2028 m and in the Great Australian Bight in 1569.6–1636 m ( Fig. 17B ).

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 15. Nothria lizae sp. nov. SEM micrographs of paratypeAM W.51446. (A) anterior part, dorsal view; (B) same, ventral view; (C) parapodium of chaetiger 1 showing lip-like extension of prechaetal lobe, ventral view; (D) parapodium of chaetiger 15 showing small branchia, dorsal view; (E) almost robust (<30 µm wide) bidentate simple hook from chaetiger 1.

Figure 16. Nothria lizae sp. nov. Line drawings of paratype SAMA E8971. (A) robust bidentate simple hook from chaetiger 1; (B) slender bidentate pseudocompound hook from chaetiger 1; (C) slender bidentate simple hook from chaetiger 2; (D) slender bidentate pseudocompound hookfrom chaetiger 2; (E) very slender bidentate serrated compound hook from chaetiger 3; (F) mandibles;(G) maxillae.

Figure 17. Nothria lizae sp. nov. (A) photograph of tube AM W.51446; (B) map of distribution; red dot represents type locality; green dots other sites of collection.