Leodice diversidentata, 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 : 29-30

Leodice diversidentata new species

( Figs 10 , 11 )

Material examined. Queensland. Brampton Island , 20°49’S, 149°17’E, beneath rocks in coral zone, coll. J. Ak, Jan 1949, AM W.197079 (HOLOTYPE), parapodia 6, 30 and 60 removed for SEM ( AM W.197079.001 ).

Description. Holotype incomplete, not well preserved with 61 chaetigers; total length 63 mm; length through chaetiger 10 12 mm; maximum width 3 m at chaetiger 10. Prostomium distinctly narrower than peristomium; median sulcus deep, wide; dorsal surface flattened; anterior edge rounded ( Figs 10D, E ; 11A, C ). Ceratophores and palpophores short, ring-shaped. Median antenna slightly longer than lateral antennae; antennae about twice as long as palps; all ceratostyles tapering to slender tips; with cylindrical articulations. Palps anterior and slightly lateral to lateral antennae. Palpostyles short, tapering with cylindrical articulations. Eyes not observed. Peristomium cylindrical; with distinctly inflated lateroventral lips. Anterior ring 5/6 of total length of peristomium. Peristomial cirri slender, tapering; without articulations; reaching middle of anterior peristomial ring.

Maxillary formula 1+1, 5+6, 7+0, 6+10, 1+1 ( Fig. 11B ). MxVI ridge-shaped. MxIII partially ventral to MxII. Mandibles missing calcareous cutting plate.

Branchiae present from chaetiger 5 to end of incomplete holotype. First branchia with a single slender filament; all other branchiae strongly pectinate ( Figs 10F, L ; 11F ). Maximum number of filaments 20 reached at chaetiger 12. Branchial stem slender, tapering; decreasing in thickness posteriorly. Filaments slender and digitiform in all branchiae; filaments relatively longer in posterior than in anterior chaetigers.

Anterior parapodia with obliquely rounded chaetal lobe ( Figs 10A, O ; 11F ). Median chaetal lobes (at chaetiger 40) decreasing in width to less than half of total width of parapodium ( Fig. 10F ). All prechaetal lobes low transverse folds. Anterior postchaetal lobes low transverse folds; median postchaetal lobes rounded and extending beyond pre and chaetal lobes on ventral side ( Fig. 10F ). First five ventral cirri thick, tapering, however, even in chaetiger three basal inflated area distinct; basal inflated region ovate and ridge-shaped in remainder of body. Free tip triangular in anteriomedian chaetigers; becoming digitiform in last twenty chaetigers present.All notopodial cirri basally slightly inflated; tapering to slender tips; articulations absent.

Slender limbate chaetae present in all chaetigers. Anteriormost pectinate chaetae slightly furled with both lateral teeth longer than other teeth ( Fig. 10C ); about 12 teeth present. Posterior to chaetiger 10, pectinate chaetae with flattened, wide-shafted; slightly flaring distally; one marginal tooth very much longer than other teeth; around 12–15 teeth present ( Figs 10I, M ; 11D, E ). Shafts of compound falciger chaetae tapering, in anterior chaetigers subdistal region distinctly serrated; becoming smooth by about chaetiger 30–35 ( Figs 10B, J, K, N, O ; 11G, H ). Most appendages bidentate, short and triangular; both teeth slender, directed distally (when worn proximal teeth appearing as low, triangular bulges). In last chaetigers examined, compound falciger chaetae have both bi- and tridentate appendages; tridentate appendages slightly thicker than bidentate ones in same chaetiger but similar in shape. Proximal tooth directed laterally; middle tooth resembling distal tooth of bidentate appendages; third tooth small, but distinct, tapering structures. Guards similar in all compound falciger chaetae; distally rounded, marginally smooth. Yellow, paired aciculae present in all chaetigers, tapering in anterior chaetigers, becoming distinctly curved distally in posterior chaetigers. Tridentate, yellow subacicular hooks present from chaetiger 20; occurring singly in a parapodium ( Fig. 10G, H ). Subacicular hooks tapering to small heads, proximal tooth large, curved, directed laterally; two distal teeth placed in tandem; one distal tooth slightly shorter than other.

Type locality. Queensland , Brampton Island, 20°49’S, 149°17’E .

Habitat. Beneath rocks in coral zone.

Etymology. The species name refers to the presence of both bi- and tridentate appendages in the compound falciger chaetae, as well as the presence of subacicular hooks with teeth in tandem.

Remarks. Leodice diversidentata n. sp., has yellow, tridentate subacicular hooks, however the teeth are in tandem rather than in a crest as is usual in species with tridentate hooks. Other species with clear or slightly yellow tridentate subacicular hooks with teeth in tandem include L. elseyi Baird, 1869 and L. flaccida Grube, 1869 . In both, the three antennae are strongly articulated with beaded antennal articulations in L. diversidentata the antennae have cylindrical articulations.

Figures

FIGURE 10. Leodice diversidentata n. sp. AM W.197079. A, parapodium 3, anterior view; B, compound falciger chaeta, parapodium 3; C, pectinate chaeta, parapodium 3; D, anterior end, dorsal view; E, anterior end, lateral view; F, parapodium 44, anterior view; G, subacicular hook, lateral view, parapodium 44; H, subacicular hook, three-quarter view, parapodium 44; I, pectinate chaeta, parapodium 44; J, compound falciger chaeta, parapodium 44. K, compound falciger chaeta, parapodium 44; L, parapodium 11, anterior view; M, pectinate chaeta, parapodium 11; N, compound falciger chaeta, parapodium 11; O, compound falciger chaeta, parapodium 11.

FIGURE 11. Leodice diversidentata n. sp. AM W.197079. A, anterior end, lateral view; B, maxillae, dorsal view; C, anterior end, dorsal view; D, aciculae and pectinate chaetae, parapodium 60; E, pectinate chaeta, parapodium 60; F, parapodium 6, anterior view; G, compound falciger chaeta, parapodium 30; H, compound falciger chaetae, parapodium 6.