Aricidea (Acmira) bbkingi, Barroso & Paiva & Ranauro, 2020

Barroso, R., Paiva, P. C. & Ranauro, N., 2020, Three new species of Aricidea (Acmira) (Annelida: Paraonidae) from the Continental Shelf of Eastern Brazil, Southwestern Atlantic, Zootaxa 4838 (3), pp. 415-426 : 423-425

Aricidea (Acmira) bbkingi sp. nov.

Figures 7–8

Type material. Holotype ( MZUSP4069 ), 19º42’12.86” S, 39º49’19.48” W, 11 m deep, 15 Dec 2010 Espírito Santo Basin , Brazil . Paratypes: 18º40’55.3” S, 38º55’41.48” W, 44 m deep, 17 Jan 2012, 1 spec ( MZUSP4070 ) ; 19º42’12.86” S, 39º49’19.48” W, 11 m deep, 15 Dec 2010, 3 specs ( UFBA1585 ) ; 19º49’57.38” S, 39º52’14.02” W, 29 m deep, 15/12/2010, 2 specs ( UFBA1586 ) .

Description. All specimens incomplete. Holotype with 33 chaetigers (paratypes: 25–36), 4.5 mm long (paratypes: 2.5–4.0 mm) and 0.2 mm wide in branchial region. Body anteriorly enlarged and dorsoventrally flattened, gradually tapering and becoming cylindrical in posterior region. Prostomium triangular, longer than wide; median antenna inserted anteriorly and reaching middle of chaetiger 1, digitiform, with two sub-distal constrictions and distally rounded ( Figs 7A ; 8A ): longer and with more constrictions in some paratypes ( Fig. 8B ). A pair of oblique nuchal organs as slits located dorsally in posterior region of prostomium ( Figs 7A ; 8 A–B), cilia not observed on prostomium. First two chaetigers with short and tuberculate notopodial postchaetal lobes; those of chaetiger 3 basally enlarged and cirriform; from branchiate chaetigers onwards, longer, slender and filiform ( Figs 7 A–B; 8A, D). Neuropodial postchaetal lobes absent ( Fig. 7 C–D). Branchiae starting from chaetiger 4, numbering 13 pairs (9–14 in paratypes); foliaceous and with sharp tips, narrower and longer in posterior part of branchiate region, mainly in last branchiate chaetigers ( Figs 7 A–B; 8A–C), bearing ciliary bands on outer margin. Anterior region with fascicles consisting of capillaries in noto- and neuropodia, bearing ca. 12–16 chaetae each; notopodial capillaries organized in a single row, neuropodial ones in two or three rows. From midbody onwards, notopodia with ca. four capillaries. Modified neurochaetae from chaetiger 23 onwards, accompanied by 2–4 capillary chaetae; recurved as hooks, bearing a tuff of distal pubescence and sometimes a short distal arista ( Figs 7D ; 8D, E ); organized in a single row numbering four at chaetiger 26 and six at chaetiger 30; in paratypes, modified chaetae start at two per chaetiger, reaching 4–7 in midbody region, reducing to 1–3 posteriorly ( Figs 7 C–D; 8D–E). Pygidium not observed.

Remarks. Aricidea (Acmira) bbkingi sp. nov. is very similar to Aricidea (Acmira) strelzovi Hartmann-Schröder & Rosenfelt (1990) from the Antarctic Peninsula, however, these species differ with regards to the morphology of antenna [wrinkled and reaching chaetiger 2 in A. (A.) strelzovi and constricted in A. (A.) bbkingi sp. nov.] and also in the maximum number of modified neurochaeta per neuropodium [five in A. (A.) strelzovi and seven in A. (A.) bbkingi sp. nov.]. Other similar species is Aricidea (Acmira) rubra , but it is differentiated by the number of pairs of branchiae [28–30 in A. (A.) rubra and 9–14 in A. (A.) bbkingi sp. nov.]. The species Aricidea (Acmira) lopezi , also has an unusual antenna (narrow at the base, broader medially and tapering to a long thread-like tip), although different from that found in A. (A.) bbkingi sp. nov. There are further morphological differences between these two species, such as the modified neurochaetae (a hook with a bent tip), and the presence of a long spine on the convex side of the chaetae in A. (A.) lopezi .

Geographic distribution and bathymetric range. Aricidea (Acmira) bbkingi sp. nov. occurs in the southwestern Atlantic Ocean, off the Brazilian coast, and in the Espírito Santo Basin, mainly in the region of the Doce river mouth, depth between 11 and 44 meters.

Substrate. In this study, this species was collected from substrates with a major percentage of mud (51%), a large part of sand (47%) and pebbles (2%). Bottom temperature was 21–26°C.

Etymology. This species is named after Riley Ben King, known as B. B. King, which means Blues Boy King, one of the best guitar players that ever played, and who the authors very much admire. B.B. King played almost until the end of his life. He passed away in 2015, at the age of 90. We are very grateful to this man for all the wonderful songs and guitar solos.

Figures

FIGURE 7. SEM of Aricidea (Acmira) bbkingi sp. nov. A, anterior region, lateral view; B, branchiate region, dorsal view; C, posterior parapodia, lateral view; D, posterior neuropodium, lateral view. Abbreviations: ant, antena; bra, branchiae; cap, capillary chaetae; cem, modified neurochaeta; lno, notopodial lobe.

FIGURE 8. Holotype of Aricidea (Acmira) bbkingi sp. nov. A, anterior region, dorsal view; B, prostomium of a paratype, dorsal view; C, largest branchiae; D, parapodium of postbranchiate region, lateral view; E, neuropodium of mid-body.