Marphysa victori, Lavesque, Nicolas, Daffe, Guillemine, Bonifacio, Paulo & Hutchings, Pat, 2017

Lavesque, Nicolas, Daffe, Guillemine, Bonifacio, Paulo & Hutchings, Pat, 2017, A new species of the Marphysasanguinea complex from French waters (Bay of Biscay, NE Atlantic) (Annelida, Eunicidae), ZooKeys 716, pp. 1-17 : 6-9

Marphysa victori sp. n. Figs 2, 3, 4

Material examined.

Holotype: AM W.49047, complete, with 470 chaetigers, ~300 mm long, with a length through chaetiger 10 of 12 mm and width of 13 mm at chaetiger 10 (11 mm without parapodia), regenerating posterior segments. Paratypes: MNHN-IA-TYPE 1805, complete, with 537 chaetigers, 386.06 mm long (approx. 77 cm live), with a length through chaetiger 10 of 15.32 mm and a width of 9.17 mm at chaetiger 10 (7.74 mm without parapodia); MNHN-IA-TYPE 1803, complete, with 414 chaetigers, 255.25 mm long, with length through chaetiger 10 of 13.70 mm and width of 10.76 mm (8.46 mm without parapodia) at chaetiger 10; MNHN-IA-TYPE 1804, complete, with 260 chaetigers, 113 mm long, with length through chaetiger 10 of 9.28 mm and width of 6.68 mm (5.9 mm without parapodia) at chaetiger 10; MNHN-IA-TYPE 1806, complete, with 307 chaetigers, 211.3 mm long, with length through chaetiger 10 of 13.17 mm and width of 8.31 mm (6.93 mm without parapodia) at chaetiger 10; MNHN-IA-TYPE 1807, complete (two fragments), with 260 chaetigers, 110 mm long, with length through chaetiger 10 of 9.87 mm and width of 7.85 mm (6.36 mm without parapodia) at chaetiger 10; MNHN-IA-TYPE 1808, complete, with 267 chaetigers, 135 mm long, with length through chaetiger 10 of 8.2 mm and width of 7.40 mm (6.39 mm without parapodia) at chaetiger 10; MNHN-IA-TYPE 1809, incomplete, with 217 chaetigers, 125.3 mm long, with length through chaetiger 10 of 11.53 mm and width of 8.7 mm (7.19 mm without parapodia) at chaetiger 10; AM W.49048, complete with 530 chaetigers, with length through chaetiger 10 of 11 mm and width of 12 mm at chaetiger 10 (10 mm without parapodia), regenerating posterior segments; AM W.49049, complete with ~350 segments, damaged in 3 places, with length through chaetiger 10 of 10 mm and width of 10 mm (8 mm without parapodia. All type material collected from Carret channel, Arcachon Bay, Bay of Biscay, France (44°40'35"N, 1°6'58"W), intertidal in muddy sediments, 20 September 2016, coll. by G. Binois.

Description

(based on holotype and paratypes). Live specimens iridescent, dark red with lighter spots, prostomium appendages and parapodia green olive, end of prostomial appendages whitish, branchial filaments red and iridescent. Recently fixed specimens olive-green to brown with lighter spots, prostomium appendages and parapodia pinkish. Preserved holotype with brown mottled pigmentation anteriorly increases in intensity towards prostomium, antennae, and palps whitish.

Body long, with same width throughout, slightly tapering at anterior and posterior ends. Prostomium shorter than anterior ring of peristomium, as wide as peristomium, bilobed with buccal lips separated by deep ventral and dorsal notch with each lobe rounded with base of them strongly pigmented (Fig. 2 A–C). Anterior ring of peristomium longer than posterior ring (2.2 to 3 times) (Fig. 2A, C). Eyes present, positioned between palps and lateral antennae (Fig. 2B), faded in larger specimens (not visible on holotype). Prostomial appendages smooth, arranged in horseshoe, slightly tapering; median antenna longer than lateral antennae, palps shortest appendages (paratypes exhibit considerable variation in the ratio of length of median and lateral antennae and of palps to a lesser extent). Antennal styles and palpostyles smooth although surface slightly wrinkled. MxI more than twice as long as carrier and five times longer than closing system. MxIII at least in part located ventral to MxII. Attachment lamella of MxIII short with irregular shape, placed at the middle of the plate. Left MxIV with attachment lamella semicircular, situated along posterior edge. Right MIV with attachment lamella semicircular, more developed in the central portion, situated along posterior edge. Maxillary formula: I=1+1, II=5+5, III=5 –6+6– 7, IV=3-4+0, V=1+1 (Fig. 3E).

Pre-chaetal neuropodia lobe inconspicuous. Post-chaetal neuropodial lobe conical in the 2-3 first chaetigers, elongate rectangular from chaetiger 4, gradually thereafter becomes wider and rounded; longer than chaetal lobe in anterior chaetigers, shorter in median and posterior chaetigers (Figs 3 A–D, 4A). Notopodial cirri triangular, occasionally digitiform in last chaetigers; longer than chaetal lobe in anterior chaetigers, shorter than chaetal lobe in median chaetigers and as long as chaetal lobe in posterior chaetigers (Figs 3 A–D, 4A). Ventral cirri from chaetiger 1 to 4-5 conical to tapering, with round wide tips, almost as long as notopodial cirri; basally inflated from chaetiger 5-6, inflated base of round shape with round tip (Figs 3D, 4A), around 1/2 as long as notopodial cirri, gradually decreasing from chaetiger 60 to 110; round with distinct tip from chaetiger 111, around 1/3 as long as notopodial cirri. Ventral cirri as long as or longer than neurochaetal lobe at anterior region (Figs 2A, 3D), slightly shorter to as long as neurochaetal lobe at median and posterior region, sometimes longer than neurochaetal lobe in posteriormost chaetigers.

Branchiae pectinate (Fig. 3 A–B), from chaetiger 32, extending posteriorly by last few chaetigers; number of branchial filaments increasing from 3 in first chaetigers to maximum 6 in mid-body, posterior chaetigers with 2 long filaments (Fig. 3C); filaments increasing in size from around 5 times longer than notopodial cirri in anterior chaetigers, around 7 times in mid-body and around 13 times in posterior chaetigers (Fig. 3C), filaments slightly annulated.

Chaetae arranged in two bundles: supra-acicular and sub-acicular, separated by a row of aciculae (Fig. 3 A–C). Aciculae dark, with lighter blunt tips, very protruding, 4-6 per parapodium in anterior chaetigers and 2-3 in mid and posterior chaetigers. Subacicular hooks absent. Supra-acicular bundle with limbate and pectinate chaetae; sub-acicular with compound spiniger chaetae (Fig. 4A). Between 25 to 35 limbate chaetae (numbers reducing posteriorly), chaetae of different lengths with hirsute blades, similar to each other. Compound spinigers present, throughout, with more than 40 spinigers within a parapodia, along whole body except last few chaetigers (Fig. 4A, B). Compound falcigers absent. Pectinate chaetae present from chaetiger 2. Up to 34 pectinate chaetae within a parapodia restricted to supra-acicular fascicle of chaetae. Pectinate chaetae of four types. In anterior parapodia, isodont, symmetrical pectinate chaetae (n<10) with 12-16 tapering minute teeth and two long outer winged teeth (nearly 3-4 times longer than inner teeth) (type 2) (Fig. 4 C–E). Median parapodia with four types of pectinate chaetae (Fig. 4 C–E): isodont, symmetrical pectinate chaetae of type 2; isodont, symmetrical pectinate chaetae with approximately 14 teeth (type 4); anodont, asymmetrical pectinate chaetae with approximately 14 teeth (type 3); anodont, asymmetrical pectinate chaetae with 2-4 large teeth (type 1) (Fig. 4 C–E). Posterior parapodia with 3 types of pectinate chaetae: isodont, symmetrical pectinate chaetae with 28 teeth (type 2); anodont, asymmetrical pectinate chaetae with nine parallel teeth (type 3); anodont, asymmetrical pectinate chaetae with 2-4 large teeth (type 1). Subacicular bundle comprising up to 40 compound spiniger chaetae in anterior chaetigers, with surface of blade hirsute (Fig. 4B).

Pygidium with only one pair of long pygidial cirri on ventral margin (approximately as long as last 15 segments), anus slightly crenulated with 12 small indentations (Fig. 2D).

Morphological variations.

Paratypes with branchiae starting from chaetigers 26 (MNHN-IA-TYPE 1808) to 28 for smaller specimens and from 28 to 34 for larger ones. Eyes clearly visible on small (MNHN-IA-TYPE 1807 and MNHN-IA-TYPE 1808) and medium specimens, more difficult to see on larger ones. One exceptional specimen (MNHN-IA-TYPE 1805) with one pair of small papillae in addition to one pair of pygidial cirri, with papillae placed more ventrally than cirri.

Etymology.

This species is named after Victor Lavesque, first and second authors’ son.

Type locality.

NE Atlantic, France, Arcachon Bay.

Habitat.

Intertidal on mudflats, under or close to oyster reefs or abandoned oyster farms, 5 to 60 cm depth. Few specimens were found in galleries into old piece of driftwood.

Genetic data.

COI gene was successfully sequenced and published at NCBI GenBank for four paratypes: MNHN-IA-TYPE 1803 (accession number: MG384997), AMW.49048 (accession number: MG384996), MNHN-IA-TYPE 1804 (accession number: MG384998) and MNHN-IA-TYPE 1806 (accession number: MG384999). 16S gene was sequenced and published at NCBI GenBank for two paratypes: MNHN-IA-TYPE 1803 (accession number: MG385000) and MNHN-IA-TYPE 1804 (accession number: MG385001) (Table 1).

As the identification of Marphysa species from the sanguinea group is very complex, molecular tools are very important. First of all, comparison of COI and 16S sequences confirmed that M. victori sp. n. was different from M. sanguinea (census Zanol et al. 2014) (Fig. 5): interspecific pairwise genetic distances were 21.8% for COI and 15.2% for 16S. Secondly, molecular analysis clearly distinguished M. victori sp. n. from other species with sequences available in GenBank (Fig. 5). Finally, they permitted us to link morphological differences to age of specimens. Indeed, intraspecific pairwise genetic distance was zero among specimens and allow to conclude that intensity of eye pigments and the segment on which the branchiae first appear was related to the size (age) of worms and not to the presence of different species.