INTRODUCTION
Five programmes monitoring benthic communities, independently carried out in the Gulf of Lions, Mediterranean, in Portuguese waters and in the Pertuis Charentais part of the Bay of Biscay led to the collection of several specimens of an unknown polynoid species. The review of these specimens during the 4th RESOMAR Benthos Taxonomic Workshop held in June 2013 in La Rochelle revealed that they belong to a hitherto unknown Malmgrenia species.
So far 10 species of Malmgrenia McIntosh, 1874 have been reported from the Mediterranean and the north-east Atlantic to which the new species M. louiseae sp. nov., described herein, has to be added (Table 1). They were either attributed to the genus Malmgrenia McIntosh, 1874 or Malmgreniella Hartman, 1967 by their respective original author and there has been some controversy in the literature regarding the correct generic name to be used (Barnich & Fiege, Reference Barnich and Fiege2001; Muir & Chambers, Reference Muir and Chambers2008). Following ICZN Opinion (2009), which ruled that the usage of the generic name Malmgrenia McIntosh, 1874 is to be conserved, at least the north-east Atlantic and Mediterranean species should now be attributed to this genus.
Fig. 1. Sampling locations of Malmgrenia louiseae sp. nov. between 2002 and 2012.
Table 1. Malmgrenia species known to occur in the Mediterranean and north-east Atlantic (cf. Pettibone, Reference Pettibone1993; Barnich & Fiege, Reference Barnich and Fiege2001, Reference Barnich and Fiege2003).
Most of these species are known to live in association with echinoderms and other invertebrates such as tubicolous or terricolous species (Barel & Kramers, Reference Barel and Kramers1977; Pettibone, Reference Pettibone1993). The potential associates are reported and a key to all Malmgrenia species found in the area is given.
MATERIALS AND METHODS
The specimens were collected from subtidal grab samples (Van Veen or Smith-McIntyre) in the following surveys or inventories of benthic macrofauna communities: CARTHAM in the Mediterranean (ASCONIT Consultants et al., 2012), Guia marine outfall monitoring programme, ACOSHELF and MeshAtlantic in Portuguese waters, OBIONE in Bay of Biscay (Table 2; Figure 1).
Table 2. Localities, geographic coordinates (WGS 84), sediment, depth, number of specimens collected and sampling dates of Malmgrenia louiseae sp. nov.
The samples were washed with seawater onboard on a 1 mm mesh size and fixed in a 4% formalin-seawater solution. They were sorted in the laboratory and the specimens preserved in a 70% ethanol solution. All observations and measurements were carried out on fixed specimens. The animals were very fragile and most of the elytra were lost and bodies fragmented during the washing steps. Also, body fragmentation and elytra losses occurred when live specimens were added to fresh water or alcohol.
The preserved specimens were studied and photographed using a stereomicroscope Leica M205C coupled to a digital camera Leica IC80HD and the Leica Application Software. Details of elytra and parapodia needed the use of a compound microscope (Leica DMIRB, coupled with a digital camera Olympus DP70 and the DP Controller software). The photographs of the holotype were used as the basis for drawings of the animal with the free vector graphics editor Inkscape.
Length (L) was measured from the anterior margin of the prostomium to the posterior border of the last segment (pharynx not included, if everted) and width (W) was taken at the widest segment, including parapodia but excluding chaetae.
The type material is deposited in the collections of the Muséum National d'Histoire Naturelle de Paris, France (MNHN), the Museu Nacional de História Natural e da Ciência de Lisboa, Portugal (MNHNC-UL) and the Senckenberg Museum Frankfurt, Germany (SMF).
SYSTEMATICS
Family polynoidae Kinberg, 1856
Genus Malmgrenia McIntosh, 1874
Type speciesMalmgrenia andreapolis McIntosh, 1874
Diagnosis (emended to include new species described herein)
Body flattened dorsoventrally, short, up to 46 segments, more or less covered by elytra or short tail uncovered (large specimens). Elytra 15 pairs on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29, 32. Prostomium bilobed, without distinct cephalic peaks, with three antennae; lateral antennae with ceratophores inserted terminoventrally; two pairs of eyes, anterior pair usually dorsolaterally in front of widest part of prostomium, posterior pair dorsally near hind margin of prostomium. Parapodia biramous, noto- and neuropodia with elongate acicular lobe; tips of noto- and neuroacicula penetrating epidermis; neuropodia with or without supra-acicular or sub-acicular process. Notochaetae with rows of spines and blunt or pointed tips; neurochaetae more numerous, with rows of spines only distally and one or two kinds of tips: bidentate with secondary tooth subdistally and/or unidentate with pointed or knob-like tip.
Malmgrenia louiseae sp. nov. (Figure 2)
Fig. 2. Malmgrenia louiseae sp. nov., holotype (MNHN POLY TYPE 1559): (A) anterior end, dorsal view; (B) left middle elytron (9th); (C) detail of lateral margin of same; (D) right cirrigerous parapodium of chaetiger 12, posterior view; (E) chaetae, E1: upper notochaetae, E2: lower notochaetae, E3: upper neurochaetae, E4: middle neurochaetae, E5: lower neurochaetae. Scale bars: A, 1 mm; B, D, 500 µm; E1, E2, C, 100 µm; E3, E4, E5, 50 µm.
TYPE MATERIAL
Holotype: 1 complete specimen (cs) (MNHN POLY TYPE 1559), L 13.7 mm W 4.3 mm for 33 segments (fragmented); Gulf of Lions, Côte Catalane, CARTHAM B50, 24 August 2010, 3°09′57″E 42°35′19.6″N; 56 m, coastal mud, leg. C. Labrune and J-M. Amouroux.
Paratypes: 1 cs (MNHN POLY TYPE 1560), L 10.5 mm W 3.7 mm for 32 segments (fragmented); Bay of Biscay, Pertuis Charentais, OBIONE, Antioche, 22 August 2011, 1°18′30″W 46°05′03″N, 35 m, coastal muddy sand, leg. J. Jourde and P-G. Sauriau.
1 cs (SMF 23918), L 12.5 mm W 3.8 mm for 34 segments (fragmented); Bay of Biscay, Pertuis Charentais, OBIONE, Antioche, 28 March 2012, 1°18′30″W 46°05′03″N, 35 m, coastal muddy sand, leg. J. Jourde and P-G. Sauriau.
1 cs (MB29-000340), L 22 mm W 5 mm for 36 segments (fragmented); off Portugal, Cascais-Guia G29(2), October 2008, 9°24′58.50″W 38°39′37.86″N, 34 m, mud, leg. L. Sampaio and V. Quintino.
2 anterior fragments (MB29-000340), L 5.5 mm W 4.5 for 12 segments and L 3 mm W 2.5 mm for 11 segments; off Portugal, Cascais-Guia G29(2), October 2008, 9°24′58.50″W 38° 39′37.86″N, 34 m, mud, leg. L. Sampaio and V. Quintino.
DIAGNOSIS
Elytral surface smooth, microtubercules totally absent, outer lateral elytral margin with few small scattered papillae, posterior margin with fewer short papillae; neuropodia with an infra-acicular process in addition to the supra-acicular process; two types of notochaetae: upper ones stout with blunt tips and lower ones slender with very pointed tips; neurochaetae all unidentate, upper tapering to long, pointed tips.
DESCRIPTION (BASED ON HOLOTYPE)
Prostomium bilobed, without cephalic peaks; median antenna with ceratophore in anterior notch, style papillate, tapering to filiform tip; lateral antennae with ceratophores inserted terminoventrally and with papillate, tapering styles; palps smooth, long, tapering; anterior pair of eyes dorsolaterally in front of widest part of prostomium, posterior pair dorsally near hind margin (Figure 2A). Tentaculophores inserted laterally to prostomium, without chaetae, with a pair of papillate dorsal and ventral tentacular cirri, tapering to filiform tip. Second segment with first pair of elytra, biramous parapodia, ventral buccal cirri obviously longer than the following ventral cirri, papillate. 15 pairs of elytra for 33 chaetigers; elytra delicate, surface smooth; outer lateral and posterior elytral margin with few short papillae; surface near the outer lateral margin with very few scattered surface papillae of variable length (some as long as the largest marginal papillae); faint pigmentation in form of isolated spot near place of attachment of elytrophore and on the inner lateral part (Figure 2B–C). Styles of dorsal cirri papillate, tapering to filiform tip, extending beyond tips of neurochaetae; styles of ventral cirri with few papillae, tapering, shorter than neuropodia (Figure 2D). Parapodia biramous, both rami with single aciculum penetrating epidermis; notopodia with short, inconspicuous rounded preacicular lobe and longer, pointed acicular lobe; neuropodia with subconical prechaetal acicular lobe with longer, digitiform supra-acicular process and shorter, but conspicuous sub-acicular process, postchaetal lobe rounded (Figure 2D). Notochaetae with distinct rows of spines and of two kinds: upper ones stout with blunt tip and lower ones slender, tapering to very fine tip (Figure 2E1–E2); neurochaetae with rows of spines only in distal part; upper tapering to long, pointed, unidentate tip, lower ones with short bent enlarged distal part ending in blunt tip, middle ones of intermediate shape with blunt distal part (Figure 2E3–E5).
HABITAT
The species is currently known from muddy substrates, between 34 to 110 m depth (Table 2). Several potential hosts were found in the stations where the new species was collected. Thus, most of the Portuguese specimens were caught with the echiurid Thalassema thalassemum (Pallas, 1766) and one with the synaptid holothurian Leptosynapta inhaerens (O. F. Müller, 1776). However, specimens of Malmgrenia louiseae sp. nov. were never observed in immediate contact with the echiurid or the holothurian. In the Bay of Biscay, all the specimens were collected with Leptosynapta cf. bergensis (Östergren, 1905) and one specimen was observed in contact with the holothurian. The Mediterranean specimens were collected with the synaptid Oestergrenia digitata (Montagu, 1815).
DISTRIBUTION
Currently known from type locality in the Western Mediterranean (Gulf of Lions) and North-east Atlantic: Portuguese coasts (Cascais-Guia, Costa da Caparica and Figueira da Foz) and Bay of Biscay (Pertuis Charentais).
ETYMOLOGY
The species is named in honour of Louise Jourde, first author's daughter, born a few months before the beginning of this work.
REMARKS
Malmgrenia louiseae sp. nov. is unique due to its neuropodial sub-acicular process present in addition to the supra-acicular process which is known from several other Malmgrenia and many other polynoid species. It might be confused with Malmgrenia lilianae (Pettibone, Reference Pettibone1993), a species originally described from the south-west Atlantic (Pettibone, Reference Pettibone1993), then reported for the Mediterranean (Barnich & Fiege, Reference Barnich and Fiege2001, Reference Barnich and Fiege2003) and now also recorded from the north-east Atlantic off Portugal (unpublished) and in the Bay of Biscay (unpublished). In both species elytra are devoid of microtubercles, with marginal papillae, and neurochaetae are exclusively unidentate. However, in M. lilianae there is only one kind of notochaetae (stout with pointed tip) and the sub-acicular process is absent. The identification key given below highlights further differences to other species in Europe.
KEY TO NORTH-EAST ATLANTIC AND MEDITERRANEAN MALMGRENIA SPECIES
1. Elytral margin with many long papillae 2
— Elytral margin with few scattered papillae or margin smooth 3
2. Elytral surface covered more or less completely by microtubercles; neurochaetae all unidentate, tapering to long, pointed tips, supra-acicular process digitiform M. polypapillata
— Elytral surface with patch of microtubercles in anterior part; neurochaetae bi- and unidentate; supra-acicular process absent M. mcintoshi
3. Elytral surface without microtubercles 4
— Elytral surface with microtubercles 5
4. Neuropodial acicular lobe with digitiform to conical supra-acicular process; short and long notochaetae stout with pointed tip; neurochaetae unidentate M. lilianae
— Neuropodial acicular lobe distally bilobed with digitiform to conical supra-acicular process and shorter sub-acicular process; short notochaetae with blunt tip, long notochaetae with slender, pointed tip; neurochaetae unidentate M. louiseae sp. nov.
5. Elytral surface covered more or less completely by microtubercles, neurochaetae usually all bidentate M. ljungmani
— Elytral surface with patch of microtubercles in anterior part; neurochaetae bi- and unidentate 6
6. Neuropodia without supra-acicular process M. marphysae
— Neuropodia with supra-acicular process 7
7. Short notochaetae stout, with blunt tip; long notochaetae slender, with pointed tip; upper and middle neurochaetae bidentate, lower unidentate M. darbouxi
— All notochaetae stout with blunt or pointed tip 8
8. Antennae and cirri smooth (short and thick) M. castanea
— Antennae and cirri papillate 9
9. Supra-acicular process small, digitiform M. lunulata
— Supra-acicular process wide bulbous or subconical 10
10. Neurochaetae usually all bidentate, unidentate neurochaetae (if present) with pointed tip M. arenicolae
— Upper and lower neurochaetae usually unidentate with knob-like tip, middle neurochaetae bidentate M. andreapolis
ACKNOWLEDGEMENTS
LS and VQ would like to thank Susan Chambers, National Museums of Scotland (UK) for commenting on the identity of the new species at an earlier stage. JJ and PGS gratefully thank Fabien Aubert, Nicolas Lachaussée, Philippe Pineau and the captain of the coastal N.O. ‘Estran’ Vincent Ottmann for their help during the sampling sessions. JJ also thanks Hélène Agogué and Eric Pante for their valuable comments. CL and PB thank the captains and crew members of N.O. ‘Thetys II’ and Alicia Romero Ramirez for assistance during samplings and Jean-Michel Amouroux for help during identification. The authors are grateful to the two anonymous referees for their corrections and valuable comments that improved the manuscript.
FINANCIAL SUPPORT
JJ was financially supported by the Région Poitou-Charentes through CPER funding, the Université de La Rochelle and CNRS. La Rochelle Taxonomic Workshop was financially supported by the RESOMAR and the Agence Nationale de Formation. LS and VQ were supported by the research projects ‘ACOSHELF’ (POCI/MAR/56441/2004-PPCDT/MAR/56441/2004), ‘Monitorização Ambiental do Emissário Submarino e da ETAR da Guia do Sistema de Saneamento da Costa do Estoril’, funded by SANEST, S.A., ‘MeshAtlantic’ (with the support of the European Union ERDF-Atlantic Area Program 2009-1/110) and by European Funds through COMPETE and National Funds through the Portuguese Science Foundation (FCT) within project PEst-C/MAR/LA0017/2013. LS benefited from a Post-doc grant (SFRH/BPD/72997/2010), given by FCT (Fundação para a Ciência e Tecnologia). The Mediterranean data used in this paper are part of the PhD Thesis of PB funded by IFREMER (convention 09/3211321) and the Agence de l'Eau Corse-Méditerranée (convention no 2010 0871). They were obtained during the monitoring program CARTHAM funded by the Agence des Aires Marines Protégées and managed as a part by the GIS Posidonie.
