Lumbrineridae sp. NHM_1485, 1930

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

Lumbrineridae sp. NHM_1485

Figs 4A-E , 5A-F

Material examined.

NHM_1485, NHM ANEA 2022.852, coll. 4 Mar. 2015, AB02, UK-1, Box core, 12.495, -116.65018, 4260 m, https://data.nhm.ac.uk/object/f44e9778-31b9-4204-8b41-f2229302bfd3; NHM_1516, NHM ANEA 2022.853, coll. 5 Mar. 2015, AB02, UK-1, EBS, 12.51317, -116.49133, 4252 m, https://data.nhm.ac.uk/object/18dad4b1-fb07-49ef-a56a-168ced070d7f; NHM_1843, NHM ANEA 2022.854, coll. 13 Mar. 2015, AB02, OMS, Megacore, 12.05465, -117.25158, 4096 m, https://data.nhm.ac.uk/object/8250bf25-7734-4db0-b18c-6ad49e5cc9f6.

Description.

Species represented by several posteriorly incomplete specimens. Voucher specimen NHM_1485, 7.5 mm long and 1 mm wide for 29 chaetigers long anterior fragment. Voucher specimen NHM_1516 (Fig. 4A ) dissolved for jaws examination and now represented by jaws only (Fig. 4B ). Molecular voucher NHM_1843 is a body fragment, identified by DNA only. Live specimen light pink colour (Fig. 4A ), with iridescent sheen and faint spotted pattern across body and prostomium; a red/orange band can be seen along dorsum. Preserved specimens pale yellow in ethanol. The anterior end of the body thick, with a distinctive large collar.

Prostomium elongated, conical, and distally pointed, longer than wide (Fig. 4A ).

Maxillary apparatus with four pairs of maxillae (Fig. 4B ). All maxillae with attachment lamellae. MI forceps-like without internal accessory teeth. MI the same length as carriers and joined completely to the base. MII with ~ 3-5 distinctive teeth, and thin sclerotised ligaments on the posterior end, ~ 2/3 the length of MI. MIII completely pigmented. MIV approximately rectangular and unidentate. Mandibles fused for only ¼ of their length.

Parapodia consistent across body length, short and rounded. Pre-chaetal lobes broad and low in all chaetigers (Figs 4C , 5A ). Branchiae present, simple, unbranched, elongated and digitiform (Fig. 4C ), best developed in anterior chaetigers (Fig. 4C, D ), at some point becoming absent (Fig. 5A ).

Chaetae characterised by narrowly limbate capillaries (Figs 4E , 5A-C ) and simple hooded hooks (Fig. 5A, D, E ). Anterior fragment, specimen NHM_1485 with narrowly limbate capillaries only in 29 chaetigers long fragment. Chaetae increase in number from chaetigers 1-8, then decrease again from chaetiger nine onwards. From chaetiger 21, there are ~ 3 chaetae. Body fragment NHM_1483 with 1-3 narrowly limbate capillaries and one or two simple hooded hooks. Hooks long and slender, multidentate, with fine dentition of ~ 5 small teeth (Fig. 5D, E ). Aciculae black (Fig. 4C, E ), tips protruding (Fig. 5F ). Posterior end and pygidium unknown.

Genetic data.

In our analysis, this species falls as a sister taxon to clade containing Augeneria species and unidentifiable CCZ specimen assigned to Lumbrineridae sp. NHM_2146 (Fig. 3 ). It has one COI match on GenBank with another unclassified annelid specimen, GenBank accession number KJ736520.1, also collected at the CCZ ( Janssen et al. 2015).

Remarks.

We were not able to confidently identify CCZ specimens to the genus-level, as they were represented by two short anterior fragments (one now dissolved for jaws) and body fragment, identified by DNA only. No hooded hooks were observed in 29-chaetiger long anterior fragment of CCZ specimen NHM_1485, but they were present in all chaetigers on the body fragment of specimen NHM_1843, which was identified by DNA. Morphologically, elements of the maxillary apparatus (four pairs of dark maxillae, all with attachment lamellae, MII with ligaments) and chaetae composition (limbate chaetae and simple multidentate hooded hooks) are characteristic of several lumbrinerid genera. The digitiform structure associated with parapodia has been interpreted as branchia, pointing to the genus Cenogenus Chamberlin, 1919 (Oug pers. comms.). Due to the uncertainty of some characters such as hooks observed from the body fragment only (Fig. 5D-E ), we identify this CCZ species to family level only and ascribe it to morphospecies Lumbrineridae sp. NHM_1485.

Distribution.

Central Pacific Ocean, Eastern CCZ, found in ‘UK-1’ and ‘OMS’ 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 4. Lumbrineridae sp. NHM _ 1485 A live image of anterior fragment of specimen NHM _ 1516 in dorsal view B complete maxillary apparatus, specimen NHM _ 1516 C parapodium from chaetiger 10 in posterior view with prechaetal (prechl) and postchaetal (postchl) lobes and branchia (br) marked by arrows, specimen NHM _ 1485 D parapodia on chaetigers 19 - 20, with branchiae (br), specimen NHM _ 1485 E limbate capillaries from anterior chaetiger, specimen NHM _ 1485. Scale bars: 100 µm (B); 50 µm (C, D). Abbreviations: br = branchiae ca. = carriers, MI = maxilla 1, MII = maxilla 2, MIII = maxilla 3, MIV = maxilla 4, al = attachment lamellae.

Figure 5. Lumbrineridae sp. NHM _ 1485, specimen NHM _ 1843 A parapodium from body fragment B limbate chaeta C detail of limbation D simple hooded hooks E detail of hooded hook dentition F acicula. Scale bars: 250 µm (A); 100 µm (B); 25 µm (C-E); 50 µm (F).