Eunice upoloae, Zanol & Hutchings & Fauchald, 2020

Zanol, Joana, Hutchings, Pat A. & Fauchald, Kristian, 2020, Eunice sensu latu (Annelida: Eunicidae) from Australia: description of seven new species and comments on previously reported species of the genera Eunice, Leodice and Nicidion, Zootaxa 4748 (1), pp. 1-43 : 16-19

Eunice upoloae , new species

( Figs 8 , 9 )

Material examined. Queensland. Little Upolo Cay, 38 km NNE of Cairns , under coral rocks, coll. & pres. I. Loch (ex P. Colman), 19 Jul 1970, AM W.4529 (HOLOTYPE), parapodia 9, 45, 225, 353 removed for SEM ( AM W.4529.001) .

Description. Holotype complete with 362 chaetigers; total length 262 mm; length through chaetiger 10 17 mm; maximum width 7 mm at chaetiger 10.

Prostomium anteriorly rounded bearing wide and shallow median sulcus; slightly depressed near palpal bases, otherwise dorsally inflated ( Figs 8D, E ; 9A, B ). Dark eyes present between palps and lateral antennae. All antennae similar in length; none extending beyond anterior peristomial ring. Median antenna a little thinner than lateral antennae. Lateral ceratophores short cylinders; median ceratophore short, ring-shaped. Ceratostyles tapering; irregularly articulated. Palpophores short cylinders; palpostyles shorter and distinctly more slender than lateral antennae; irregularly articulated. Peristomium tapering slightly anteriorly; ventrolateral lips distinct. Anterior peristomial ring 4/5 of total peristomial length. Separation between ring distinct ventrally and dorsally; indistinct on a short lateral section. Peristomial cirri reaching middle of anterior peristomial ring; basally slightly inflated; tapering to slender tips; articulations absent.

Maxillary formula 1+1, 7+6, 7+0, 6+13, 1+1. MxVI absent ( Fig. 9D ). MxIII short; forming part of distal arc with left MxIV and V. Left MxIV running dorsal to ventral, teeth restricted to the dorsal half, and with basal plate along most of the plate. Mandibles missing calcareous cutting plate.

Branchiae pectinate, present from chaetiger 9 to chaetiger 177, first branchia with three filaments; best developed branchia at around chaetiger 30 with 12 filaments ( Fig. 8F, K ). Branchiae much longer than notopodial cirri; shafts slender, tapering; filaments slender, digitiform, filaments longer than notopodial cirri in chaetigers where branchiae best developed. Last 30 branchiae single filaments. Chaetal lobes rounded with acicula emerging in dorsal half, becoming pointed with acicula emerging medially in posterior chaetigers ( Figs 8C, F, K, P ; 9G, H ). Pre- and postchaetal lobes low transverse folds in all chaetigers; in anteriormost chaetigers dorsalmost end of both slightly higher, projecting slightly from upper edge of chaetal lobes. Anterior ventral cirri basally slightly inflated, those of chaetiger 3 base markedly inflated; tapering to oblique tips; median ventral cirri basally distinctly inflated; inflated bases forming elongated ridges; free tips rounded, posteriorly ventral cirri becoming more digitate, without inflated base. Anterior notopodial cirri basally slightly inflated; becoming tapered in median chaetigers; articulations absent.

Slender tapering limbate chaetae present in all chaetigers. Pectinate chaetae in all chaetigers, tapering and furled with 15–20 slender teeth; one or both marginal teeth longer than inner teeth, longer marginal teeth of unequal length ( Figs 8A, H, J, O ; 9C, F, J, K ). Shafts of compound falciger chaetae distally slightly inflated with fine serrations ( Figs 8B, G, I, M ; 9E ). Appendages short, tapering; decreasing in length posteriorly. Both teeth directed distally in all chaetigers; in anterior chaetigers proximal tooth distinctly shorter than distal tooth; in median chaetigers teeth similar in length. Guards distally symmetrically bluntly pointed; fine serrations present. Aciculae and subacicular hooks with black cores and clear sheaths. Aciculae blunt or tapering to fine tip; single or double per parapodium ( Figs 8C, F, K, P ; 9G, H, I ). Subacicular hooks first present from chaetiger 38; always single. Hooks bidentate; tapering abruptly distally to distinct head; distal tooth triangular, erect; proximal tooth curving distally with convex ventral edges and slightly concave dorsal edges; proximal tooth distinctly larger than distal tooth ( Fig. 8L, N ).

Type locality. Little Upolo Cay , 38 km NNE of Cairns, Queensland .

Habitat. Under coral rocks.

Etymology. The species name refers to the name of the key, Little Upolo Key, near where the type was collected.

Remarks. Eunice upoloae resembles E. afra and similar taxa, especially E. flavapunctata ( Treadwell, 1922) in having dark subacicular hooks and aciculae, with branchiae starting posterior to chaetiger five and short antennae. The structure of the appendages of the compound chaetae is unique in the genus in that both teeth are directed distally and are similar in length in median and posterior chaetigers.

Figures

FIGURE 8. Eunice upoloae n. sp. AM W.4529. A, pectinate chaeta, parapodium 3; B, compound falciger chaeta, parapodium 3; C, parapodium 3, anterior view; D, anterior end, dorsal view; E, anterior end, lateral view; F, parapodium 25, anterior view; G, compound falciger chaeta, parapodium 25; H, pectinate chaeta, parapodium 25; I, compound falciger chaeta, parapodium 50; J, pectinate chaeta, parapodium 50; K, parapodium 50, anterior view; L, subacicular hook, parapodium 50; M, compound falciger chaeta parapodium 316; N, subacicular hook, parapodium 316; O, pectinate chaeta, parapodium 316; P, parapodium 316, anterior view.

FIGURE 9. Eunice upoloae n. sp. AM W.4529.A, anterior end, lateral view; B, anterior end, dorsal view; C, pectinate chaetae, parapodium 9; D, maxillae, dorsal view; E, compound falciger chaetae, parapodium 9; F, pectinate chaetae, parapodium 45; G, parapodium 225, anterior view; H, parapodium 45, anterior view; I, aciculae, parapodium 9; J, pectinate chaeta, parapodium 9; K, pectinate chaeta, parapodium 225.