Leodice tasmaniae, 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 : 34-35

Leodice tasmaniae new species

( Figs 14 , 15 )

Material examined. Tasmania. Off St. Patricks Head, 41°39’S, 148°14’E, 1100 m depth, coll. K.J. Graham on F. R . V . Soela , Jul 1987, AM W.22313 (l, HOLOTYPE) parapodia 3, 17, 85, 133 removed for SEM ( AM W.22313.001), AM W.22314 (4, PARATYPES), AM W.22315 (14) .

Description. Holotype complete with 137 chaetigers; total length 163 mm; length through chaetiger 10 7 mm; maximum width 7 mm at chaetiger 10.

Prostomium about as wide as peristomium, but only about 1/2 as deep; anteriorly rounded with distinct dorsal depressions around palpal bases, with relatively shallow and wide median sulcus ( Fig. 14E, F ). Ceratophores and palpophores short, ring-shaped. Median antenna distinctly longer than lateral antennae; reaching about chaetiger 8. All ceratostyles tapering with cylindrical irregular articulations at the distal half. Palpostyles slender and tapering with five regular cylindrical articulations at the distal 1/3; distal articulations increasingly drop-shaped. Palps extending to chaetiger 2. Eyes posterior to palps; dark. Peristomium flaring anteriorly; ventrolateral lips distinct, but not strongly muscular. Anterior ring 4/5 of total peristomial length; separation between rings conspicuous dorsally and ventrally, absent laterally. Peristomial cirri reaching posterior edge of prostomium; slender with gently inflated bases tapering to slender tips; with four or five irregular cylindrical articulations.

Maxillary formula 1+1, 6+6, 7+0, 3+10, 1+1, 1+1 ( Fig. 15A ). MxIII part of distal arc with left MxIV and MxV. Base of left MxIV wide, but cutting edge narrower with very short teeth ( Fig. 15C ). Flat mandible with cutting plates wider than long ( Fig. 15B ).

Branchiae present from chaetiger 8 to end of body; where best developed, with three filaments; two well developed, one very small ( Figs 14G, K ; 15G, J ). Most branchiae with two filaments only. All branchiae very much shorter than notopodial cirri; relatively longer in posterior than in anterior chaetigers.

Chaetal lobes distally rounded; anteriorly nearly symmetrical, becoming increasingly asymmetrical posteriorly with increasingly elongated ventral portion ( Figs 14A, G, K ; 15D, G, J, N ). Anterior prechaetal lobes transverse folds, becoming increasingly asymmetrical in median to posterior parapodial, following the shape of the chaetal lobe closely. Anterior and posterior postchaetal lobes similar to corresponding pre-chaetal lobes; median postchaetal lobes about as high as chaetal lobes, rounded; located distinctly ventral to chaetal lobes, thus visible in anterior view. Anterior notopodial cirri with distinct cirrophores; each slightly inflated basally with three or four irregular articulations; articulations lost by chaetiger 15–20. Inflated basal portion absent in posterior parapodia; posterior notopodial cirri inflated medially rather than basally. Notopodial cirri extending beyond all other parapodial structures in all parapodia. Anterior and posterior ventral cirri digitiform; anteromedian ventral cirri basally inflated with ovate bases and distinct, tapering free tips from chaetiger 9 to 56.

Slender, tapering limbate chaetae present in all parapodia. All pectinate chaetae furled with one marginal tooth longer than other teeth; anterior and median ones with about ten teeth; posterior pectinate chaetae slightly flaring with about 15 teeth ( Figs 14D, H, L ; 15E, K, L, M ). Shafts of all compound falciger chaetae distally slightly inflated; marginally lightly serrated ( Figs 14B, C, I, M ; 15F, I ). Appendages bidentate, proximal tooth split in a few chaetae ( Fig. 14C ). Anterior appendages strongly tapering with very small heads in dorsal positions; ventral ones less distinctly tapering, resembling ones in posterior chaetigers. Distal tooth slender and tapering in all chaetigers. Anterior and far posterior appendages with proximal tooth directed laterally, triangular. Median appendages with proximal tooth tapering, directly distally. Aciculae and subacicular hooks yellow. Paired aciculae present in all parapodia ( Figs 14N ; 15H ). Subacicular hooks present from chaetiger 47; occurring sporadically over next 20 chaetigers; thereafter present in all chaetigers; usually single, but paired hooks present in about 1/3 of chaetigers. Hooks tapering distally to small, bidentate head; both teeth directed distally, similar in size and shape ( Fig. 14J ). Anus terminal on a very short pygidium; dorsal pair of pygidial cirri very long, slender; without articulations, ventral pair short, peg-shaped ( Fig. 14O ).

Type locality. Tasmania, Off St. Patricks Head, 41°35’S, 148°14’E, 1100 m depth .

Distribution. The new species is known only from one locality at the eastern end of Bass Strait close to the Tasmanian coast.

Etymology. The species name refers to Tasmania, close to the type locality of the species.

Variation. Four paratypes complete, 105 mm long with 120 chaetigers, 135 mm long with 125 chaetigers, 185 mm long with 129 chaetigers and 175 mm long with 137 chaetigers. Start of brachiae on chaetiger 8 or 9. Subacicular hooks first present on chaetiger 35, 37, 47 and 46, more posterior in longer specimens. Inflated bases of ventral cirr vary from chaetiger 8 or 9 to chaetiger 50 to 55.

Remarks. The new species belongs to group A2 of Eunice (subacicular hook yellow bidentate, branchiae present in more than 65% of chaetiger starting before chaetiger 10; Fauchald 1970, 1992), which is currently recognized as belonging to the genus Leodice , because of the light color of the subacicular hooks ( Zanol et al. 2014). Other species in the same group are Leodice armillata Treadwell, 1922 , L. gracilicirrata Treadwell, 1922 , L. leptocirris (Grube, 1870) n. comb., L. parasegregata ( Hartmann-Schröder, 1965) n. comb. and L. stigmatura Verrill, 1900 . Branchiae are present from chaetiger 3 in L. gracilicirrata , L. leptocirris , L. parasegregata and L. stigmatura ; L. armillata has branchiae from chaetiger 6 and L. tasmaniae n. sp. from chaetiger 8. The maximum number of branchial filaments is three in L. tasmaniae n. sp. and L. armillata , five in L. stigmatura , six in L. leptocirris , seven in L. gracilicirrata and 18 in L. parasegregata . Branchiae in L. armillata are longer than notopodial cirri contrasting from the ones of L. tasmaniae n. sp., which are shorter. Ceratostyles and palpostyles lack articulations in L. leptocirris . The other four species have some kind of articulation. Those in L. gracilicirrata have distal indistinct articulations, L. armillata are moniliform, the other three have basally cylindrical articles, which may become more or less drop-shaped distally. In branchial features the new species most closely resembles L. armillata , but they differ in the articulation of ceratostyles and palpostyles.

Figures

FIGURE 14. Leodice tasmaniae n. sp. AM W.22313.A, parapodium 3, anterior view; B, compound falciger chaeta, parapodium 3; C, compound falciger chaeta, parapodium 3; D, pectinate chaeta, parapodium 3; E, anterior end, lateral view; F, anterior end, dorsal view; G, parapodium 20, anterior view; H, pectinate chaeta, parapodium 20; I, compound falciger chaeta, parapodium 20; J, subacicular hook, parapodium 110; K, parapodium 110, anterior view; L, pectinate chaeta, parapodium 110; M, compound falciger chaeta, parapodium 110; N, acicula hook, parapodium 110; O, posterior end, dorsolateral view.

FIGURE 15. Leodice tasmaniae n. sp. A–C, AM W.22314. D–N, AM W.22313. A, maxillae, dorsal view; B, mandible, ventral view; C, left maxillary plates III, IV, V e VI, dorsal view; D, parapodium 3, anterior view; E, pectinate chaeta, parapodium 85; F, compound falciger chaetae, parapodium 17; G, parapodium 17, anterior view; H, aciculae, parapodium 85; I, compound falciger chaetae, parapodium 85; J, parapodium 85, anterior view; K, pectinate chaetae, parapodium 3; L, pectinate chaetae, parapodium 17; M, pectinate chaeta, parapodium 113; N, parapodium 113, anterior view.