Augeneria sp. NHM_4590

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_4590

Figs 6A-G , 7A-F

Material examined.

NHM_0209, coll. 14 Oct. 2013, AB01, UK-1, Box core, 13.82412, -116.53425, 4054 m, https://data.nhm.ac.uk/object/1b024172-3aba-4404-9cd5-6f9cc86d69c0; NHM_0609, coll. 17 Feb. 2015, AB02, UK-1, EBS, 12.38624, -116.54867, 4202 m, https://data.nhm.ac.uk/object/98e583f4-665d-4197-8349-c8f6147454b8; NHM_0205, NHM ANEA 2022.832, coll. 14 Oct. 2013, AB01, UK-1, Box core, 13.82412, -116.53425, 4054 m, https://data.nhm.ac.uk/object/2af3e568-87be-4158-9b8e-f5b1c3cc5468; NHM_0686, NHM ANEA 2022.841, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/1b1830d0-ec8f-4503-86ca-72efba0a4772; NHM_0782, NHM ANEA 2022.842, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/10adaf27-6b76-4258-8530-5cb8ef631c44; NHM_0788, NHM ANEA 2022.843, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/87c4f766-d47b-4bf4-85e3-b5e234cdf241; NHM_1008, NHM ANEA 2022.833, coll. 24 Feb. 2015, AB02, OMS, EBS, 12.13367, -117.292, 4122 m, https://data.nhm.ac.uk/object/9338cf46-ea85-43d8-9593-1d2395acb4ca; NHM_1872, NHM ANEA 2022.844, coll. 13 Mar. 2015, AB02, OMS, EBS, 12.0415, -117.21717, 4094 m, https://data.nhm.ac.uk/object/621a4712-aea8-42c6-8ad9-ee673f0d06c6; NHM_1878, NHM ANEA 2022.845, coll. 13 Mar. 2015, AB02, OMS, EBS, 12.0415, -117.21717, 4094 m, https://data.nhm.ac.uk/object/cd9d9fd6-547d-4b98-b111-d47e647333bf; NHM_1948K, NHM ANEA 2022.846, coll. 13 Mar. 2015, AB02, OMS, EBS, 12.0415, -117.21717, 4094 m, https://data.nhm.ac.uk/object/8e37077f-b5ff-4190-a75e-23dd07314798; NHM_2249, NHM ANEA 2022.836, coll. 1 Mar. 2015, AB02, OMS, EBS, 12.25733, -117.30217, 4302 m, https://data.nhm.ac.uk/object/d2bc88ee-e882-4f6d-aa4c-93bcdb429611; NHM_2389, NHM ANEA 2022.834, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/5cd29524-9ddf-43a0-8618-5ec8f6dc0bf8; NHM_2588, NHM ANEA 2022.838, coll. 1 Mar. 2015, AB02, OMS, EBS, 12.25733, -117.30217, 4302 m, https://data.nhm.ac.uk/object/22fbc1a3-b2bd-40c2-bf7f-d3dcd6b85ea4; NHM_2976, NHM ANEA 2022.839, coll. 20 Feb. 2015, AB02, UK-1, EBS, 12.51317, -116.60417, 4425 m, https://data.nhm.ac.uk/object/efc8baac-defe-468f-a40d-5b0c2e160621; NHM_3886, NHM ANEA 2022.835, coll. 6 Mar. 2020, RC01, UK-1, Box core, 13.59013, -116.46817, 4081 m, https://data.nhm.ac.uk/object/10ae7a30-345f-40b0-9fb6-ec84eb4d91d5; NHM_4590, NHM ANEA 2022.837, coll. 15 Mar. 2020, RC01, OMS, Box core, 12.32636, -120.02542, 4157 m, https://data.nhm.ac.uk/object/4ed5a4c7-a44a-4cce-8e0b-4a5036fd5b5c; NHM_4738_ECDS4, NHM ANEA 2022.840, coll. 28 Feb. 2020, RC01, UK-1, Box core, 13.98698, -116.47664, 4059 m, https://data.nhm.ac.uk/object/fc4ac1a4-1a78-475f-a9bc-36740d2e1bd9.

Description.

Species represented by complete specimen NHM_4590 and several posteriorly incomplete specimens. Voucher specimen NHM_4590 in two fragments, anterior fragment 5.5 mm and 0.85 mm wide for 33 chaetigers, posterior fragment 8 mm long for ~ 50 chaetigers. Voucher specimen NHM_0205 (Fig. 6A ), 2.3 mm long and 0.5 mm wide for 14 chaetigers long anterior fragment. Voucher specimen NHM_2249 (Fig. 7A ) represented by body fragment and jaws only as anterior end tissues dissolved for jaws observation (Fig. 7B ). Live specimen pale yellow to translucent, with distinct white spotted pattern across each chaetiger (Fig. 6A ), spotted pattern also on prostomium in two triangular peaks along the ventral side and lateral edge. Pattern lost in specimens preserved in ethanol; some larger specimens with yellow-orange tint when preserved in ethanol, smaller specimens appear white; slight red pigmentation runs down the dorsal side of the body in some specimens e.g., NHM_2249 (Fig. 7A, C ). Body wide anteriorly tapering slightly towards posterior, chaetigers becoming more bead-like towards posterior.

Prostomium broadly conical, distally rounded, ca. as long as wide (Fig. 6A ), with a spotted pattern that is slightly visible when preserved in ethanol, prostomium can also appear slightly pear-shaped (Fig. 7A ).

Maxillary apparatus with four pairs of maxillae, central areas non-pigmented, with dark edges (Figs 6C , 7B ). All maxillae with attachment lamellae. MI and MIV appear darker around the edges. MI with enlarged base that connects with carriers, though overlapping the edge of them. MI forceps-like, slender and hooked towards posterior end. Carriers pointed with a lateral incision and are equal in length to MI. MII with ~ 3 teeth, with short ligaments. MIII small, darker along anterior lateral edge. MIV large and oval shaped spanning the width of the maxillary apparatus, with a dark edge and pale interior. Mandibles fused along ¾ of length, slightly divergent at both ends (Fig. 7B ).

Parapodia uniramous, large, and distinct (Fig. 6B, D ). Pre-chaetal lobe small and rounded. Postchaetal lobe elongated, digitiform, pointing towards the posterior of the body almost parallel from parapodia 1-9 after which the base of the parapodia becomes wider and the lobes begin to point away from the body. Posterior postchaetal lobes appear globular and reduced (Fig. 7D ). Darker spots of colouration at the base of parapodia.

Chaetae characterised by limbate capillaries, compound multidentate hooded hooks and simple multidentate hooded hooks. Chaetigers 1-8 with ca. two compound multidentate hooded hooks and limbate chaetae (Figs 6D , 7E-F ). In some specimens, chaetiger 8 with one simple and one compound multidentate hooded hook. Compound multidentate hooks with short blades, with ~ 6 small teeth in lateral view (Fig. 6F ). Chaetiger 9 onwards with 2-4 simple multidentate hooded hooks only (Fig. 6G ). Aciculae yellow. Posterior chaetigers with two simple multidentate hooded hooks only (Fig. 7F ).

Pygidium observed in posterior fragment of specimen NHM_4590, with four short, subdistally inserted, distally narrowing cirri.

Genetic data.

This species falls within a well-supported monophyletic clade containing Augeneria species, another CCZ species included in this paper - Augeneria sp. NHM_0851 and unidentifiable CCZ specimen Lumbrineridae sp. NHM_2146 (Fig. 3 ). There is one COI match to this species on GenBank with an unassigned species also collected from the CCZ, GenBank accession number KJ736519.1 ( Janssen et al. 2015).

Remarks.

This species can be varied in appearance, for example specimen NHM_2249 (Fig. 7A ) has a pear-shaped prostomium, whereas in specimen NHM_0205 it is rounded (Fig. 6A ). Additionally, variations in patterning and colouration have been observed (Figs 6E , 7C ), with several specimens having a prominent orange colouration in the anterior. Nevertheless, genetic data identified only one species, so the observed variability is best explained as intraspecific. The form of the hooks has been interpreted as compound, but they may approach the pseudo-compound form with the slit apparently being closed at one side (Oug, pers. comms.).

The maxillary apparatus and chaetae composition of this species are indicative of the genus Augeneria Monro, 1930. Molecular data also support assignment of this species to genus Augeneria (Fig. 3 ). This CCZ species resembles Augeneria bidens (Ehlers, 1887) based on re-description by Carrera-Parra (2001), who examined the type specimens. The type locality for Augeneria bidens is in the Gulf of Mexico and Caribbean Sea in depths of 214-348 m (original description as Lumbriconeris bidens Ehlers, 1887). It has also been documented in Maryland to North Carolina in the US waters ( Fauchald et al. 2009). The maxillary apparatus is described by Carrera-Parra (2001) as follows; carriers shorter than MI and rounded anteriorly; well-developed attachment lamellae; MII with three rounded teeth; MIII and MIV with pale central and dark peripheral areas ( Carrera-Parra 2001). Compound hooks have a similar distribution as in CCZ specimen by being present between chaetigers 1 and 7-15, with simple hooks present from chaetigers 8-16 ( Carrera-Parra 2001). Carrera-Parra remarks that the position of transition between compound and simple hooks is size dependant. However, the CCZ species can be distinguished by the form of MIV, which is semi-circular (Figs 6C , 7B ) rather than square-shaped as in A. bidens and by having much longer mandibles (Fig. 7B ). No antennae were observed in CCZ specimens. Lastly, A. bidens has been described from much shallower depths (214-348 m) compared to ~ 4500 m for the CCZ species. 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_4590.

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.