Dodecaceria saeria Paterson & Neal, 2020

Neal, Lenka, Paterson, Gordon L. J., Blockley, David, Scott, Ben, Sherlock, Emma, Huque, Cate & Glover, Adrian G., 2020, Biodiversity data and new species descriptions of polychaetes from offshore waters of the Falkland Islands, an area undergoing hydrocarbon exploration, ZooKeys 938, pp. 1-86 : 1

Dodecaceria saeria Paterson & Neal sp. nov. Figures 25 , , 27

Material.

Holotype: Sample T5MFB, 610 m, -53.028677, -59.067642, coll. 02/02/2009, ind. 1, NHM.2018.23622. Paratypes: Sample 55MFB, 449 m, -49.24526, -59.064154, coll. 18/03/2012, ind. 1, NHM.2018.25370. Sample 3MFC, 464 m, -49.232681, -59.114021, coll. 16/04/2012, ind. 1, NHM.2018.25371.

Description.

Holotype NHM.2018.23622, anterior body brown in colour becoming lighter down body; cylindrical or slightly dorso-ventrally flattened indistal segments around pygidium in particular; paratype NHM.2018.25371, 16 mm in length with 90 segments. Ventral groove present in abdominal segments (Fig. 25c ).

Prostomium trapezoid with a narrow slightly rounded free edge. Peristomium short. Dorsal tentacles arising laterally, long and club-shaped, first pair of branchiae arise dorsal to dorsal tentacles. Two or three pairs branchiae, 2nd pair smaller than first, approximately half to two-thirds the length, 3rd pair same length as 2nd pair (Figs 25a, b ; 26a ).

No achaetous segment, chaetigerous segments start after peristomium. Anterior chaetigers with simple capillaries, five in notopodia and four in neuropodia. Spines beginning on chaetiger 22-29; podia with mix of capillaries and spines, up to six spines and four to five capillaries, becoming 8-13 spines in fascicules of distal chaetigers. Spines with excavated tips, smooth edges. Chaetigers of pygidial area with only capillaries.

Posterior chaetigers flattened, slightly widened laterally and slightly excavated ventrally, pygidium ventral with large rounded lobe dorsally (Figs 25c ; 26b ).

Tube blind-ended, hard, calcareous with mineral inclusions; surface smooth (Fig. 25e ).

Remarks.

Seven species of Dodecaceria have been recorded in the region (see Table 4 and Fig. 27 ). Three species also have two or three pairs of branchiae: D. gallardoi Carrasco, 1977b from Chile, D. laddi Hartman, 1954 from the Marshall Islands, and D. laddi oculata Hartmann-Schröder, 1962 from Peru. Dodecaceria saeria sp. nov. appears to differ from these species in the shape of the spoon-like spines (Fig. 22 ) and in the position where these spines first arise, chaetiger 22 to 29 as compared with much earlier in the three other species.

Etymology.

This species is named after the South Atlantic Environmental Research institute (SAERI) which has done so much to support the taxonomic work included in this paper.

Distribution.

This species has only been recorded from the Falkland Islands. Dodecaceria species are more commonly associated with rock or shell burrowers. The log of the cruise states "Mostly black gravel up to 1.5cm diameter in sieve residue" which may account for the occurrence of this taxon in predominately soft sediment.

Figures

Figure 22. Aphelochaeta cf. longisetosa Falkland Islands specimen - MGSP plate a ventrolateral view of anterior end b dorsal view of anterior end.

Figure 25. Dodecaceria saeria sp. nov. (holotype NHM. 2018.23622) a general views of anterior and posterior ends of worm b close-up of anterior c pygidium d chaetae of mid-body chaetiger e tube.

Figure. 26. Dodecaceria saeria sp. nov. a dorso-lateral view of anterior end b pygidium and distal segments.

Figure 27. Comparison of spines of Dodecaceria species recorded from the region a D. gallardoi Carrasco, 1977 b D. choromytilicola Carrasco, 1977; D. fistulicola Ehlers, 1901 d D. multifiligera Hartmann-Schroeder, 1962 e D. laddi oculata Hartmann-Schroeder, 1962 f D. meridiana Elias & Rivero, 2009 g D. saeria sp. nov.