Marphysa sanguinea (Montagu, 1813)
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publication ID |
https://dx.doi.org/10.3897/zookeys.859.34117 |
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publication LSID |
lsid:zoobank.org:pub:1EBB6796-08EB-4F12-83FB-4CE146055DFC |
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persistent identifier |
https://treatment.plazi.org/id/4E654A4D-B611-50E3-AC20-DE5B25F410DF |
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treatment provided by |
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scientific name |
Marphysa sanguinea (Montagu, 1813) |
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Marphysa sanguinea (Montagu, 1813) Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3
Material examined.
MNHN-IA-TYPE 1856, one complete specimen, Mount Edgcumbe, Plymouth Sound, Cornwall, UK (50°20'59"N, 4°09'52"W), intertidal in soft rocks, 04 November 2017. MNRJP002048, one complete specimen, Mount Edgcumbe, Plymouth Sound, Cornwall (UK) (50°20'59"N, 4°09'52"W), intertidal in soft rocks, 04 November 2017. AM W.51410, one complete specimen, Mount Edgcumbe, Plymouth Sound, Cornwall (UK) (50°20'59"N, 4°09'52"W), intertidal in soft rocks, 04 November 2017. MNHN-IA-TYPE 1857, one complete specimen, Pyla, Arcachon Bay, France (44°33'57"N, 1°14'16"W), subtidal in turf slab (8m depth), 29 October 2017. AM W. 49085, one complete specimen, Logonna-Daoulas, Bay of Brest, France (48°19'37"N, 4°19'27"W), intertidal in soft rocks, 18 October 2016. AM W.49086, Logonna-Daoulas, Bay of Brest, France (48°19'37"N, 4°19'27"W), intertidal in soft rocks, 18 October 2016, several parapodia mounted for SEM. AM W. 27392, one complete specimen, Devon, Plymouth, Mount Edgcumbe (50°21'10"N, 4°09'30"W), intertidal from burrows in rock crevices, 25 October 1999.
Description.
Body relatively long, with complete individuals ranging from 48.1 (ca. 138 chaetigers) to 163.1 mm (ca. 270 chaetigers) in length and from 3.7 to 6.6 mm in width (chaetiger 10 with parapodia), with same width throughout, slightly tapering at anterior end and abruptly tapering at posterior end. Body cylindrical on anterior chaetigers, becoming dorsoventrally flattened. Prostomium slightly 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 ( Fig. 1B, C View Figure 1 ). Anterior ring of peristomium longer than posterior ring (2 to 3 times) ( Fig. 1B, C View Figure 1 ). Eyes present, positioned posteriorly between palps and lateral antennae ( Fig. 1C View Figure 1 ). Prostomial appendages slightly wrinkled, arranged in arc on the posterior margin of the prostomium; median antenna longer than lateral antennae reaching first chaetiger ( Fig. 1A View Figure 1 ), palps shortest appendages ( Fig. 1A, C View Figure 1 ). MI more than three times as long as carrier and five times longer than closing system. MIII located ventroanterior to MII. Attachment lamella of MIII long and thin, placed at the middle of the plate. Left MIV with attachment lamella semicircular, thin, situated along anterior edge. Right MIV with attachment lamella semicircular, larger than left one, situated along anterior edge. Maxillary formula: I=1+1, II=3‒4+5, III=6-7+0, IV=4+5‒6, V=1+1 ( Fig. 1D View Figure 1 ).
First few parapodia smaller than subsequent ones but all similar in structure. Notopodial cirri elongate and triangular ( Figs 1C View Figure 1 , 2A View Figure 2 ), digitiform in last chaetigers ( Fig. 2C View Figure 2 ); longer than chaetal lobe. Ventral cirri from chaetiger 1 to 4-5 conical to tapering, with round wide tips, shorter than notopodial cirri ( Fig. 2A View Figure 2 ); basally inflated from chaetiger 5-6, inflated base of round shape with round tip ( Figs 1B View Figure 1 , 2B View Figure 2 ); last chaetigers with triangular cirri ( Fig. 2C View Figure 2 ). Pre-chaetal lobe inconspicuous; post-chaetal lobe from first chaetigers triangular swollen ( Fig. 2A View Figure 2 ), longer than chaetal lobe, becoming inconspicuous from ca. chaetigers 15-20 ( Figs 2B, C View Figure 2 ). Branchiae pectinate, from chaetiger 21 (from chaetiger 13 for small specimens) ( Figs 1A View Figure 1 , 2B View Figure 2 ), extending posteriorly by last 5-15 chaetigers; number of branchial filaments increasing from one in first chaetigers to maximum four in mid-body ( Fig. 2B View Figure 2 ), posterior chaetigers with two filaments; filaments slightly annulated.
Chaetae arranged in two bundles: supra-acicular and sub-acicular, separated by a row of aciculae. Aciculae dark, tapering, very protruding, 1-4 per parapodium in anterior chaetigers and 2-3 in mid and posterior chaetigers. Single subacicular bifid hook present from chaetiger 21-25 to nearly end of body, dark on base to middle and translucent at the distal end ( Figs 2D View Figure 2 , 3D View Figure 3 ). Supra-acicular bundle with limbate and pectinate chaetae; sub-acicular with compound spiniger chaetae. Between 10 to 20 limbate chaetae, chaetae of different lengths with hirsute blades, similar to each other. Pectinate chaetae present from chaetiger 2-3 (with up to 28 pectinate chaetae within a single parapodia), restricted to supra-acicular fascicle. Pectinate chaetae of two types. In anterior parapodia, isodonts narrow (n <10) with long internal teeth (with ca. 14-15 tapering teeth) and two long outer winged teeth (nearly 2-3 times longer than inner teeth) (type 1) ( Fig. 3A View Figure 3 ). Median and posterior parapodia with two types of pectinate chaetae ( Fig. 2C View Figure 2 ): thin, isodonts narrow, with ca. 25 short teeth (type 1) ( Fig. 3B, C View Figure 3 ); anodonts wide pectinate chaetae with long and thick teeth (n = 6-14) (type 2) ( Fig. 3C View Figure 3 ); Type 2 less numerous (3-7) than type 1 (16-22). Compound spinigers with hirsute shafts and “socket-like” articulations ( Fig. 2A View Figure 2 ), present along whole body, with more than 30 spinigers within a parapodia. Compound falcigers absent.
Pygidium with only one pair of relatively short pygidial cirri on ventral margin (approximately as long as last five chaetigers), anus slightly crenulated.
Remarks.
Specimens both from British and French coasts agree with the description of the neotype and with voucher AM W.27392 which was also compared in the neotype description by Hutchings and Karageorgopoulos (2003). Most morphological characteristics are within the variation range of those observed by Hutchings and Karageorgopoulos (2003). However, few differences can be noticed: (1) larger number of pectinate chaetae (up to 28, instead of 10-14) beginning from chaetiger 2-3 (instead of chaetiger 1-2), (2) presence of coarsely denticulate chaetae with less teeth (6-14 teeth instead of ca. 14). These variations are typical within a species in the Marphysa genus.
Molecular data.
COI gene was successfully sequenced and published at NCBI GenBank for the tree specimens sampled in Cornwall near the locality type (Table 1). COI was also successfully sequenced for specimens sampled in Brest and in Arcachon (Table 1).
First of all, molecular analysis distinguished M. sanguinea from other species with sequences available in GenBank ( Fig. 4 View Figure 4 ). Analysis permitted the grouping of specimens of M. sanguinea from Cornwall together with specimens from French Atlantic coast (Arcachon, Brest) but also from southern English Channel, Callot Island ( Zanol et al. 2014) ( Fig. 4 View Figure 4 ). Intraspecific pairwise genetic distances for COI were zero among these specimens. This tree clearly emphasised the presence of different species among this sanguinea complex. Especially, some specimens registered as M. sanguinea did not belong even to the Marphysa genus (EU352317 and EU352316).
Finally, a comparison of sequences of COI of a specimen from the type locality (AM W.51410) with specimen used to sequence the complete mitochondrial genome of M. sanguinea (accession number: KF733802, specimen from China) ( Li et al. 2016) was performed. Unsurprisingly, these sequences were very different; the interspecific pairwise genetic distance was 18.5%.
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