Augeneria sp. NHM_0851

Neal, Lenka, Abrahams, Emily, Wiklund, Helena, Rabone, Muriel, Bribiesca-Contreras, Guadalupe, Stewart, Eva C. D., Dahlgren, Thomas G. & Glover, Adrian G., 2023, Taxonomy, phylogeny, and biodiversity of Lumbrineridae (Annelida, Polychaeta) from the Central Pacific Clarion-Clipperton Zone, ZooKeys 1172, pp. 61-100 : 61

Augeneria sp. NHM_0851

Fig. 8A-G

Material examined.

NHM_0420, coll. 20 Oct. 2013, AB01, UK-1, ROV, 13.86367, -116.54432, 4011 m, https://data.nhm.ac.uk/object/bde33da0-8f07-470a-b63a-979326313974; NHM_0737, NHM ANEA 2022.850, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/a9119f6d-0787-40a4-87cd-08cc80d8b35b; NHM_0761, NHM ANEA 2022.847, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/52a58501-7bfc-4dcc-af95-0509a6463600; NHM_0851, NHM ANEA 2022.848, coll. 21 Feb. 2015, AB02, UK-1, Box core, 12.57903, -116.72378, 4218 m, https://data.nhm.ac.uk/object/71820a17-178d-4fcd-b493-8fac5f8b45cb; NHM_2441, NHM ANEA 2022.849, coll. 17 Feb. 2015, AB02, UK-1, EBS, 12.38624, -116.54867, 4202 m, https://data.nhm.ac.uk/object/a0b38651-82c1-4410-a352-33da931260ad.

Description.

Species represented by several posteriorly incomplete specimens. Voucher specimen NHM_0851 (Fig. 8A ), 5.8 mm long and 0.75 mm wide for 34 chaetigers long anterior fragment.

Live specimen with translucent iridescent colouration and distinctive white spotted pattern across chaetigers and prostomium (Fig. 8A ), with red spots at each parapodium and faint central line running down the ventral side of the body. Preserved specimens milky white to yellow with parapodial spots visible.

Prostomium conical, wide at base, distally narrowing, ca. as long as wide (Fig. 8A ). Peristomium prominent forming wide collar (Fig. 8A ).

Maxillary apparatus with four pairs of maxillae, central areas non-pigmented, with dark edges (Fig. 8B ). All maxillae with attachment lamellae. MI ca. equal length to carriers, with wide base on the anterior end that overlaps. MII slightly shorter or equal length than MI, with ligaments. MIV forms a squarish plate with dark edges and a pale centre. Mandibles fused for ~ ½ their length.

Parapodia in anterior wider and shorter with small rounded pre-chaetal lobes and long digitiform postchaetal lobes (Fig. 8C ), in the posterior the base becomes elongated and postchaetal lobes become significantly shorter and conical (Fig. 8D ).

Chaetae characterised by limbate capillaries, compound multidentate hooded hooks and simple multidentate hooded hooks. Capillaries long and slender, narrowly limbate (Fig. 8E ). Chaetigers 1-11 with two or three compound multidentate hooded hooks and winged capillaries, except for chaetiger 5 which has four hooks. Compound multidentate hooks with short blades, with ~ 6 small teeth in lateral view (Fig. 8F ). Chaetiger 10 with one simple multidentate hooded hook, and two compound multidentate hooded hooks. Chaetiger 11 onwards with simple multidentate hooded hooks along with limbate chaetae. Simple hooks with ~ 6 small teeth in lateral view (Fig. 8G ). Chaetiger 25 onwards, with two simple multidentate hooded hooks only. Aciculae yellow. Posterior and pygidium unknown.

Genetic data.

This species falls within a well-supported monophyletic clade containing Augeneria species, another CCZ species included in this paper - Augeneria sp. NHM_4590 and unidentifiable CCZ specimen Lumbrineridae sp. NHM_2146 (Fig. 3 ).

Remarks.

Chaetae composition and maxillary apparatus are indicative of the genus Augeneria Monro, 1930. Similarly, to Augeneria sp. NHM_4590, form of the hooks has been interpreted as compound, but they may approach pseudo-compound form with the slit apparently being closed at one side (Oug, pers. comms.) This species was numerous within our samples. However, we were unable to match the description with any known species. It can be distinguished from Augeneria sp. NHM_4590 also found in CCZ samples by mainly the shape of MIV and MII. In Augeneria sp. NHM_0851 MIV are more squarish (Fig. 8B ) rather than semi-circular (Figs 6C , 7B ) and MII has rounded rather than pointed teeth as in Augeneria sp. NHM_4590. This species also shares some characters with Augeneria verdis Hutchings & Murray, 1984, though it differs in the lack of obvious green colouration. Additionally, Augeneria sp. NHM_0851 has carriers with a distinct lateral incision, whereas the carriers in Augeneria verdis are described as triangular with a “shallow” incision.

Given that no Augeneria species have been described from the abyssal depths to date, the CCZ specimens likely represent a new species, but further taxonomic work will be necessary. Currently, we assign the CCZ specimens to morphospecies Augeneria sp. NHM_0851.

Distribution.

Central Pacific Ocean, Eastern CCZ, found in ‘UK-1’, ‘OMS’ and ‘NORI-D’ exploratory areas (Fig. 1 ).

Figures

Figure 1. Map of CCZ of exploration areas and Areas of Particular Environmental Interest (APEI) with targeted areas (highlighted in colours; see legend) where samples for this study were collected.

Figure 3. Majority rule consensus tree from the Bayesian analyses using combined datasets for COI, 16 S and 18 S genes, with 36 terminal taxa of which Tainokia logachevae (Oenonidae), Eunice rubra (Eunicidae) and Nothria conchylega (Onuphidae) were used as outgroup. Posterior probability values are marked on nodes.

Figure 6. Augeneria sp. NHM _ 4590 A Live image of specimen NHM _ 0205 in lateral view B parapodia 5 - 7 (right to left), specimen NHM _ 1008 C complete maxillary apparatus specimen NHM _ 0205, inset - annotated image of the same taken in situ D compound multidentate hooded hooks and limbate capillary chaetae on chaetiger 4, specimen NHM _ 0205 E spotted parapodia pattern anterior specimen NHM _ 1008 F detail of compound multidentate hooded hook on chaetiger 4, specimen NHM _ 0205 G simple multidentate hooded hooks on chaetiger 30 specimen NHM _ 3886. Scale bars: 50 µm (B); 100 µm (C, E); 25 µm (F, G). Abbreviations: ca. = carriers, MI = maxilla 1, MII = maxilla 2, MIII = maxilla 3, MIV = maxilla, al = attachment lamellae.

Figure 7. Augeneria sp. NHM _ 4590 A anterior end of live specimen NHM _ 2249 in dorsal view B complete maxillary apparatus specimen NHM _ 2249 (attachment lamella of MI indicated by rectangle) C spotted pattern on dorsum, specimen NHM _ 2249 D posterior globular post-chaetal lobe, specimen NHM _ 2249 E simple multidentate hooded hook and compound multidentate hooded hook on chaetiger 8, specimen NHM _ 2249 F posterior simple multidentate hooded hook specimen NHM _ 4590. Scale bars: 100 µm (B); 500 µm (C); 50 µm (D, E, F). Abbreviations: ca. = carriers, MI = maxilla 1, MII = maxilla 2, MIII = maxilla 3, MIV = maxilla 4, md. = mandibles.

Figure 8. Augeneria sp. NHM _ 0851 A live specimen NHM _ 0851, anterior end in dorsal view B complete maxillary apparatus, insert - annotated in situ image of the same, specimen NHM _ 0420 C parapodium 7 with well-developed postchaetal lobe, specimen NHM _ 0851 D parapodia 29 and 30, specimen NHM _ 0851 E compound multidentate hooded hooks and limbate chaetae from anterior chaetiger F compound multidentate hooded hook on chaetiger 9, specimen NHM _ 0851 G simple multidentate hooded hook chaetiger 10, specimen NHM _ 0851. Scale bars: 125 µm (B insert); 100 µm (C, D); 50 µm (E); 25 µm (E, F, G). Abbreviations: ca. = carriers, MI = maxilla 1, MII = maxilla 2, MIII = maxilla 3, MIV = maxilla 4, al. = attachment lamellae.