Marphysa davidattenboroughi, Lavesque & Zanol & Daffe & Flaxman & Hutchings, 2023

Lavesque, Nicolas, Zanol, Joana, Daffe, Guillemine, Flaxman, Beth & Hutchings, Pat, 2023, Two new species of Marphysa (Annelida, Eunicidae) from southern Australia., Zootaxa 5277 (1), pp. 113-130 : 123-127

Marphysa davidattenboroughi n. sp.

Figures 3 (D–F), 4 (D–F), 5–6

LSIDurn:lsid:zoobank.org:act: 05E797D2-8619-4D70-B99D-1296F927E43F

Material examined. Holotype. NMV F183073 , complete, some chaetigers mounted for SEM, Australia, Bass Strait , Inverloch channel, - 38.64° S 145.72° E, intertidal, 13 March 2012 . Paratypes. NMV F183071 , complete, in two parts, Inverloch channel, - 38.64° S 145.72° E, intertidal, 13 March 2012 . NMV F183072 anterior part only, some parapodia used for molecular analysis, Inverloch channel, - 38.64° S 145.72° E, intertidal, 13 March 2012 . NMV F173654 , complete, some parapodia used for molecular analysis, Armstrong Bay (Rogers Rocks), - 38.37° S, 142.35° E, intertidal, 24 February 2011 . NMV F173653 , complete, some chaetigers mounted for SEM and some parapodia used for molecular analysis, Armstrong Bay (Rogers Rocks), - 38.37° S, 142.35° E, intertidal, 24 February 2011 . NMV F306235 , complete, some parapodia used for molecular analysis, Armstrong Bay (Rogers Rocks), - 38.37° S, 142.35° E, intertidal, 24 February 2011 . NMV F303038 ,, complete, some chaetigers mounted for molecular analysis, Australia, Bass Strait, Mallacoota, Bastion Point, - 37.5° S 149.75° E, intertidal, 1 March 2018 . NMV F303032 , complete, Australia, Bass Strait , Mallacoota, Bastion Point, - 37.5° S 149.75° E, intertidal, 1 March 2018 .

Description (based on holotype, with variation in parentheses for paratypes). Live specimens strongly iridescent, body brownish to reddish, branchial filaments dark red ( Fig. 5A–B ). Preserved specimens whitish, about 210 (167– 261) chaetigers, about 83 mm (48–120) long, 2.8 mm (3.9–5.5) width at chaetiger 10, excluding parapodia. Body elongate and tapered gradually at posterior end ( Fig. 5A–B ).

Prostomium strongly bilobed, with an anterior notch, dorsoventrally flattened, anteriorly rounded (truncate) ( Fig. 5A, C ). Palps and antennae slender and tapering, arranged in an arc on posterior margin of prostomium. Median antenna isolated by gap from lateral antennae and palps, shorter than lateral ones; antennae longer than palps, longer than prostomium ( Fig. 5A–C ). Median and lateral antennae of about same length, folding back to chaetiger 3 (2). Palps shortest, reaching back to chaetiger 1 (2). Ceratostyles and palpostyle slender and tapering, all with indistinct cylindrical articulations, appear wrinkled. Ceratophores ring-shaped (cylindrical) and palpophores cylindrical. Eyes present, one pair, black, between palps and lateral antennae. First peristomial ring twice as long as second one dorsally ( Fig. 5A–C ). Separation between peristomial rings distinct on all sides.

Maxillary formula as follows: MF = 1+1, 5+5, 6(5)+0, 4+6(5–7), 1+1, MVI absent ( Fig. 5E ). Maxillary carrier approximately 2.5 times shorter than MI; rectangular anteriorly, triangular posteriorly, with a pair of rounded wings situated at posterolateral margins. MI forceps-like, without attachment lamellae, falcal arch extended at sub-right-angle, basal outer edge ached. Closing system approximately 4 times shorter than MI. Ligament between MI and MII dark brown. MII without attachment lamella, teeth triangular, distributed in less than half of plate length. Ligament between MII and MIII light brown. MIII, single, longer than left MIV, curved, with equal-sized triangular teeth, without attachment lamella. Left MIV short (less than half the size of right MIV), left-most teeth longer than right-most ones; attachment lamella dark, wide and high. Right MIV long, with teeth triangular, decreasing in size posteriorly; attachment lamella wide and high, dark. MV, paired, as long as high. Mandibles dark brown, with concentric stripes; longer than MI; cutting plates whitish, with distinct growth rings.

First few parapodia located ventro-laterally, but gradually positioned dorso-laterally in subsequent segments. Dorsal cirri slender, tapering, longer than ventral cirri ( Figs 3D–F ; 4D ). Pre-chaetal lobe shorter than chaetal lobe along whole body ( Figs 3D–F ; 4D–F ). Post-chaetal lobe longer than chaetal lobe in anterior chaetigers, conical until chaetigers 5–8 ( Fig. 4D ), wide tapering thereafter, median and posterior post-chaetal lobes shorter than chaetal lobe ( Fig. 4E–F ). Ventral cirri bluntly conical, with rounded tip, shorter than post-chaetal lobes anteriorly; basally inflated from chaetiger 4, slightly longer than post-chaetal lobes, thumb-shape thereafter ( Figs 3D–F ; 4D–E ). Branchiae pectinate, commencing from chaetiger 19 (14–21) and continuing to near end (40 last chaetigers without branchiae), very short in few first chaetigers, longer thereafter reaching mid-dorsal line from chaetiger 30; number of filaments increasing from one anteriorly to four in mid-body, decreasing to two in last several chaetigers ( Fig. 5A–B ); branchial filaments around twice as long as branchial stem, where best developed.

Notoaciculae present in dorsal cirri. Neuroaciculae black, blunt to tapering, some mucronate, approximately three per parapodium in anterior and middle chaetigers, and two per parapodium in posterior chaetigers. Supra-acicular chaetae with limbate capillaries and pectinates; present from first chaetiger to near pygidium ( Fig. 6A ). Two types of pectinate chaetae identified. Type 1: thin, narrow isodont with about 15 short and slender internal teeth, each tooth prolonged by a thin filament, outer teeth long, whip-like, commencing from first chaetigers to near end ( Fig. 6D–E ). Type 2: thick, wide anodont with 4–6 long internal and thick teeth, each tooth prolonged by a thin filament, commencing from mid-body to the end ( Fig. 6D–E ). Subacicular chaetae with compound falcigers and subacicular hooks. Compound falcigers bidentate, commencing from first chaetiger to near pygidium, blades relatively longer in anterior than posterior chaetigers, serrated guard, numbering up to 50 in anterior chaetigers decreasing in number towards posterior end ( Fig. 6B ). Subacicular hooks unidentate, transparent to golden yellow, present in all chaetigers from CH 34 (30–36) to near end and inferior to bundle of falcigers, one per parapodium, rarely two ( Fig. 6C ).

Pygidium with crenulated margin, dorsally positioned, with one pair of tapering pygidial cirri attached ventro-laterally ( Fig. 5D ).

Etymology. This species is dedicated to the legend and great naturalist Sir David Attenborough, Lifetime Patron of the Australian Museum, for educating generations on the importance of observing and protecting nature.

Type locality. South Pacific, Australia, Bass Strait, Victoria, Inverloch .

Distribution. Australia, Bass Strait, Victoria, Inverloch, Armstrong Bay and Bastion Point (Mallacoota).

Habitat. Intertidal, in sediment between stones.

Remarks. With the presence of compound falcigererous chaetae along the whole body, Marphysa davidattenboroughi n. sp. belongs to the Aenea-group ( Glasby & Hutchings 2010). In Australia, three species belonging to this group occur: M. bifurcata Kott, 1951 , M. pseudosessiloa Zanol, da Silva & Hutchings, 2017 and M. sessilobranchiata Hartmann-Schröder, 1984 .

Marphysa davidattenboroughi n. sp. differs from M. bifurcata and M. pseudosessiloa and M. sessilobranchiata Hartmann-Schröder, 1984 in several features, such as the presence of a bilobed prostomium which is rounded for the other ones, by the presence of pectinate branchiae instead of palmate ones and by the presence of thick, wide anodont pectinate chaetae with 4–6 long internal and thick teeth, which are absent in the other three species. Marphysa birfurcata and M. pseudossessiloa also differ from M. davidattenboroughi n. sp. in having bidentate subacicular hooks and two pairs of pygidial cirri. Bifurcated dorsal cirri, which are present in M. bifurcata , are absent in M. davidattenboroughi n. sp. Finally, M. davidattenboroughi n. sp. differs from M. sessilobranchiata by the presence of eyes and free branchial stems which are completely fused to body wall in M. sessilobranchiata .

Four other species belonging to the Aenea-group have been described from areas close to Australia: Marphysa papuaensis Lavesque, Daffe, Glasby, Hourdez & Hutchings, 2022 (type locality: Papua New Guinea), M. soembaensis Augener, 1933 (type locality: Indonesia), M. unibranchiata Knox & Cameron, 1970 (type locality: New Zealand) and M. zanolae Lavesque, Daffe, Glasby, Hourdez & Hutchings, 2022 (type locality: Papua New Guinea). Marphysa davidattenboroughi n. sp. differs from M. papuaensis by the presence of unidentate subacicular hooks instead of bidentate ones, a pygidium with a single pair of cirri, instead of two and the absence of eyes and the absence of thick, wide anodont pectinate chaetae with 4–6 long internal and thick teeth. Marphysa davidattenboroughi n. sp. differs from M. soembaensis by branchiae starting from chaetiger 19 instead of chaetiger 40, by the presence of unidentate subacicular hooks instead of bidentate ones and by the absence of thick, wide anodont pectinate chaetae with 4–6 long internal and thick teeth in M. soembaensis . Marphysa davidattenboroughi n. sp. differs from M. unibranchiata by unidentate subacicular hooks instead of bidentate ones and by the absence of thick, wide anodont pectinate chaetae with 4–6 long internal and thick teeth in M. unibranchiata . Finally, M. davidattenboroughi n. sp. differs from M. zanolae by having a single pair of pygidial cirri instead of two pairs and by the absence of eyes and thick, wide anodont pectinate chaetae with 4–6 long internal and thick teeth in M. zanolae .

The most similar species to M. davidattenboroughi n. sp. is M. aenea (Blanchard in Gay, 1849) as described in Orensanz (1990) based on specimens from the Southwest Atlantic Ocean (coasts of Uruguay and Argentina). They share a similar prostomium, branchiae, notopodial and ventral cirri, and thin pectinate chaetae. They differ in the length of prostomial appendages in relation to prostomium and in the shape of the teeth of the compound falciger chaetae. Also, Orensanz (1990) describes posterior pectinate chaetae large with few coarse teeth but does not illustrate it, and therefore we cannot be sure it is the same chaetae observed in M. davidattenboroughi n. sp.

Based on COI, and with a nodal support of 98%, M. davidattenboroughi n. sp. clearly differs from species for which sequences are available, especially species from the same region: M. bifurcata , M. papuaensis , M. pseudosessiloa and M. zanolae ( Fig. 7 ). The Pair-wise Kimura 2-parameter (K2P) between M. davidattenboroughi n. sp. and other species varies between 14.2 and 33.3% confirming the separation in relation to the other sequenced species.

Figures

FIGURE 3. Schematic representation of parapodia of Marphysa baudini n. sp., holotype AM W.35513 (A–C) and Marphysa davidattenboroughi n. sp., paratype NMV F173654 (D–F). A. parapodia from anterior body (chaetiger 43); B. parapodia from mid-body (chaetiger 109); C. parapodia from posterior body (chaetiger 203); D. parapodia from anterior body (chaetiger 40); E. parapodia from mid-body (chaetiger 110); F. parapodia from posterior body (chaetiger 206). Key: Ac, aciculae; Dc, dorsal cirri; Vc, Ventral cirri; Sah, subacicular hook.

FIGURE 4. SEM images of parapodia of Marphysa baudini n. sp., holotype AM W.35513 (A–C) and Marphysa davidattenboroughi n. sp., paratype NMV F173653 (D–F). A. parapodium from anterior body (chaetigers 9–11); B. parapodia from mid-body (chaetiger 107); C. parapodia from posterior body (chaetigers 270–271); D. parapodia from anterior body (chaetigers 4–7); E. parapodia from mid-body (chaetigers 112–117); F. parapodia from posterior body (chaetigers 157–160). Key: ChL, chaetal lobe; Dc, dorsal cirri; Sah, PreL, pre-chaetal lobe; PostL, post-chaetal lobe; Vc, ventral cirri.

FIGURE 5. Marphysa davidattenboroughi n. sp., paratype NMV F183071 (A–B), paratype NMV F173654 (C, E), paratype NMV F713653 (D). A–B. Live specimens (photos made by L.Altoff); C. Anterior end, dorsal view; D. Pygidium, ventral view; E. Maxilla and mandibles, dorsal view.

FIGURE 6. SEM images of Marphysa davidattenboroughi n. sp., paratype NMV F173653. A. Parapodia, chaetiger 22; B. Falciger chaeta, chaetiger 22; C. Sub-acicular hook, chaetiger 67; D. Pectinate chaetae, chaetigers 157–159; E. Pectinate chaeta, chaetiger 67; F. Pectinate chaetae, chaetiger 157. Numbers in white circles indicate the type of pectinate chaetae.

FIGURE 7. Majority-rule consensus tree of Marphysa species from Bayesian analysis using COI. Asterisk indicates posterior probability> 80%. Text in red indicates specimens used in this study.