Hydrobiologia 496: 163–173, 2003.E. Sigvaldadottir, A.S.Y. Mackie, G.V. Helgason, D.J. Reish, J. Svavarsson, S.A. Steingrımsson & G. Guðmundsson (eds),Advances in Polychaete Research.© 2003 Kluwer Academic Publishers. Printed in the Netherlands.

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The Magelonidae (Annelida: Polychaeta) from the Seychelles,with the description of three new species

Kate Mortimer & Andrew S. Y. MackieDepartment of Biodiversity & Systematic Biology, National Museum of Wales, Cathays Park,Cardiff CF10 3NP, Wales, U.K.E-mail: Katie.mortimer@nmgw.ac.uk

Key words: Magelona, Meredithia, Octomagelona, Magelonidae, Polychaeta, new species, Seychelles, IndianOcean

Abstract

Three new species of Magelona are described from the Seychelles: M. conversa, M. falcifera and M. gemmata.Magelona conversa belongs to a ’M. mirabilis group’, having a rounded prostomium and specialised chaetae onchaetiger 9, but differs from all other members in having long prechaetal neuropodial lamellae on chaetigers 1–8. Magelona falcifera bears large sickle-shaped hooded hooks in the abdomen and thus approaches the genusMeredithia, but lacks prostomial horns. Magelona gemmata belongs to a ’M. longicornis group’ in having distinctprostomial frontal horns, and a thorax with lanceolate postchaetal lamellae in the notopodia and ventral neuropodiallobes. The distinctively swollen bud-like tips on the notopodial lamellae of chaetiger 9 are an unique feature. Thestatus of Meredithia Hernández-Alcántara & Solís-Weiss, 2000 and current magelonid terminology are discussed.

Introduction

In March 2000, the National Museum of Wales moun-ted a marine biological expedition to the Seychellesunder the auspices of the Royal Society-Royal Geo-graphical Society’s Shoals of Capricorn programme.The polychaetes of the Seychelles have been the sub-ject of relatively few taxonomic studies to date (e.g.,Potts, 1910; Westheide & Hass-Cordes, 2001), and theMagelonidae none.

At the present time, there are approximately 60recognised magelonid species. Almost all are in-cluded in the genus Magelona Müller, 1858. However,two species were recently described for MeredithiaHernández-Alcántara & Solís-Weiss, 2000 and onefor Octomagelona Aguirrezabalaga, Ceberio & Fiege,2001. Twenty Magelona species have been describedfrom the Indian Ocean/Indo-West Pacific region; M.capensis Day, 1961 and M. cincta Ehlers, 1908 (SouthAfrica), M. obockensis Gravier, 1906 (Red Sea), M.cornuta Wesenberg-Lund, 1949, M. puchella Mo-hammad, 1970 and M. heteropoda Mohammad, 1973(Arabian Gulf), M. kamala, M. tinae, M. pygmaea, M.petersenae, M. methae, M. mickminni, M. pectinata

and M. noppi Nateewathana & Hylleberg, 1991 (Thai-land), M. crenulifrons and M. lenticulata Gallardo,1968 (Viet Nam), M. koreana and M. japonica Okuda,1937 (Korea), M. agoensis Kitamori, 1967 (Japan),and M. sachalinensis Buzhinskaja, 1985 (SakhalinIsland).

In addition, the following North and South Amer-ican species have also been recorded in this area:M. rosea Moore, 1907 (Thailand: Fauvel, 1953),M. californica Hartman, 1944, M. pitelkai Hartman,1944, and M. longicornis Johnson, 1901 (Japan: Kit-amori, 1967) and M. papillicornis F. Müller, 1858(Madagascar: Day, 1962; Red Sea: Amoureux, 1983).

This first study of the Seychelles magelonids(Shoals of Capricorn publication P018) includes de-tailed descriptions of three new species and dis-cussions regarding their affinities with known spe-cies. The status of the genus Meredithia Hernández-Alcántara & Solís-Weiss, 2000 is examined.

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Figure 1. Positions of benthic sampling stations, Seychelles Exped-ition 2000.

Materials and methods

The Seychelles material was all collected during theNational Museum of Wales expedition to the island ofMahé in March 2000. The aims of the expedition wereto collect polychaete and mollusc specimens for taxo-nomic research, and benthic samples for biodiversityassessments.

All samples in this paper were obtained from aseries of sublittoral stations around Mahé (Fig. 1) us-ing the modified 0.1 m2 Van Veen grabs (station replic-ates designated a, b, c . . .) first successfully deployedin the Irish Sea in 1997 (Wilson et al., 2001) or Tjärnödredge. Samples were sieved (0.5 mm mesh) and fixedin formalin, mostly stained with Rose Bengal. Spe-cimens were subsequently preserved in 80% alcoholwith 2% propylene glycol (Mackie & Oliver, 1996).

All drawings were made using a camera lucidattachment on a Wild M8 or Wild MZ9.5 zoom micro-scope, or Nikon Labophot-2 compound microscope.

Specimens are herein recorded as complete (c),anterior fragments (af), posterior fragments (pf) orfragments (f), as detailed in Fiege et al. (2000).Lateral pouches on abdominal chaetigers were re-corded here according to the morphologies describedby Fiege et al. (2000): � configuration – anteriorlyopen pouches (often convoluted) bounded dorsallyand ventrally by large cuticular flaps; C configura-tion – posteriorly open pouches, often inconspicuous,ventral part sometimes folded over, flattening pouch

against body. Parapodial structures are primarily de-scribed relative to basic polychaete terminology (e.g.,postchaetal, prechaetal etc.), however, certain of theterms introduced by Jones (1971, 1978) are also given(e.g., dorsal medial lobe – DML, ventral medial lobe– VML, ventral neuropodial lobe – VNL) to facilitatecross-comparisons with other publications.

All type material is deposited in the NationalMuseum of Wales (NMW), Cardiff.

Systematics

Magelonidae Cunningham & Ramage, 1888Magelona F. Müller, 1858; emended Fiege et al.(2000)Magelona conversa new species (Fig. 2)Material examined: Seychelles: SE of Mahé, Stn 2a(4◦ 42.97′ S, 55◦ 32.41′ E), coarse quartz, calcareoussand/gravel, 30 m, holotype (NMW.Z.2000.020.0001;c) and 2 paratypes (NMW.Z.2000.020.0002; 1c,1af dissected), Van Veen 2 (VV2), 7.03.00;Stn 2b (4◦ 42.96′ S, 55◦ 32.35′ E), coarsequartz, calcareous sand/gravel, 30 m, 1 para-type (NMW.Z.2000.020.0003; c), VV2, 7.03.00.—NW of Mahé, Stn 8a (4◦ 35.39′ S, 55◦ 22.40′E), medium-coarse quartz, calcareous sand, 41 m,1 paratype (NMW.Z.2000.020.0004; af, f), VV2,9.03.00; Stn 8b (4◦ 35.49′ S, 55◦ 22.58′ E), medium-coarse quartz, calcareous sand, 42 m, 3 paratypes(NMW.Z.2000.020.0005; 1c, 2af, f), VV2, 9.03.00.— NE of Mahé, Stn 6c (4◦ 37.08′ S, 55◦ 32.02′E), medium-coarse calcareous sand, 26 m, 1 paratype(NMW.Z.2000.020.0006; c), VV2, 8.03.00; Stn 52(4◦ 36.69′ S, 55◦ 33.72′ E), medium-coarse calcareoussand, 32 m, 5 paratypes (NMW.Z.2000.020.0007; 3c,2af, f), VV4, 23.03.00.Diagnosis: Prostomium longer than or equal to width,subtriangular, without prostomial horns. Notopodiaof chaetigers 1–8 with smooth-edged foliaceous post-chaetal lamellae, superior prechaetal processes (DML)from chaetiger 5–7 (often 6) to 8. Neuropodial pre-chaetal lamellae longer than postchaetal lamellae onchaetigers 1–8. Chaetigers 1–8 with capillary chaetae.Chaetiger 9 with mucronate chaetae. Abdominal lat-eral lamellae rounded subrectangular. Hooded hooksbidentate, main fangs unidirectional, pointing later-ally. Lateral pouches of both � and C configurationson abdominal chaetigers.Description: A moderately stout species; thorax nar-rower than abdomen, constricted at chaetiger 9, with

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Figure 2. Magelona conversa n. sp. (A, P. holotype; B. paratype, NMW.Z.2000.020.0007; C-O. paratype, NMW.Z.2000.020.0002). (A)Anterior region, dorsal view; (B) Prostomium; (C–D) Chaetiger 1, anterior and posterior views; (E–F) Chaetigers 4 and 6, anterior views;(G–H) Chaetiger 8, anterior and posterior views; (I) Chaetiger 9, anterior view; (J–K) Chaetigers 10 and 22, anterior views; (L) Outer lateralchaeta, chaetiger 9; (M) Mucronate chaeta, distal part, chaetiger 9; (N–O) Bidentate hooded hooks, abdomen; (P) Posterior region, dorsal view.

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marked differences between the two regions. Holotypeentire, thorax (including prostomium) 6.9 mm long,1.3 mm wide, total length 40 mm for 58 chaetigers.Entire paratypes (7) 29–57 mm with 51–68 chaetigers.

Prostomium longer than or equal to width (L:Wratio 1.0–1.1), subtriangular, anterior margin smoothand rounded, prostomial horns and eyes absent (Fig.2A, B); four prominent longitudinal dorsal muscularridges, inner pair joined for majority of length, outertwo abutting inners. Proboscis a large heart-shapedsac, with conspicuous longitudinal ridges inferiorly;superior surface smooth. Palps arising ventrolaterallyfrom base of prostomium, short, reaching chaetigers6–10; papillated almost to base (non-papillated regionreaching to chaetiger 1–2). Palps with 4–5 rows ofpapillae proximally, 2–3 distally, either side of ventralgroove; outermost papillae longest.

Peristomium achaetous, of equal size to chaetiger1. Chaetigers 1–7 similar; parapodia biramous withsmall rounded notopodial prechaetal lamellae which,from chaetiger 5–7 (often 6) to 8, project dorsally asdigitiform to triangular processes (DML). Prechaetallamellae confluent with large foliaceous postchaetallamellae (Fig. 2C–F). In general, postchaetal lamellaedecrease in length from chaetiger 1 to mid-thorax andincrease in size from chaetiger 6 to 8. Neuropodia withlong triangular prechaetal lamellae; postchaetal lobesshort, rounded triangular. Ventral neuropodial lobes(VNL) absent.

Chaetiger 8: notopodial prechaetal lamellae similarto preceding chaetigers, but superior processes larger;postchaetal lamellae very large, foliaceous (Fig. 2G,H). Neuropodial prechaetal lamellae broader and moretriangular than previously; postchaetal lamellae well-developed, rounded oblong. Chaetae of chaetigers 1–8all capillary.

Chaetiger 9: segment short and narrow. Notopodialand neuropodial prechaetal lamellae low and broadlyrounded, encircling chaetae cuff-like to form higherpostchaetal lamellae (Fig. 2I). Neuropodial prechaetallamellae inferiorly developed as large protruding tri-angular processes (VML of other authors; see ‘Dis-cussion’). Chaetae arranged in fan-like arcs; spatulate(Fig. 2M), distally narrower (Fig. 2L) towards marginsof each fan.

Abdominal chaetigers with subrectangular laterallamellae, directed towards each other, of about equalsize in both rami (Fig. 2J, K), internally supportedby 6-8 conspicuous curved aciculae (‘arcuate setae’).Aciculae slender, individually sheathed, continuousbetween rami; distal regions of sheaths (within post-

chaetal lamellae) expanded as small rounded vesicles.Lateral lamellae extend postchaetally on anterior ab-dominal chaetigers; postchaetal part reduced or absentby around chaetiger 20–25 (Fig. 2K). Basal regionsof lateral lamellae initially broad, becoming narrowerand longer on median chaetigers, lamellae assumingmore pedunculate form; reducing in size on posteriorsegments. No prechaetal lamellae. Small digitiform totriangular processes (DML & VML) evident through-out at inner margins of chaetal rows, decreasing in sizeposteriorly (papilliform on posteriormost chaetigers).

Abdominal chaetae all bidentate hooded hooks(Fig. 2N, O), of similar size. Hooks of unidirectionalorientation, main fangs pointing laterally. Initiallyabout 18 hooks per ramus, decreasing to about 6–12on median and posterior chaetigers.

Paired lateral pouches (� configuration) present onanterior abdominal segments (Fig. 2A), often chaeti-gers 11, 14, 17 and 20. Unpaired lateral pouches (Cconfiguration) found posteriorly, on alternate chaeti-gers, more or less regularly. On holotype pouchespresent on chaetigers 11, 14, 17, 20, 23R, 25L, 27R,29L, 31R, 33L, 35R, 37L, 39R, 41L, 43R, 45L, 47R,49L, 52L, 53R, and 55L.

Pygidium small, truncate, with two stout lateralanal cirri (Fig. 2P).Colour: No living animals observed, all but onespecimen stained with Rose Bengal; cream-white inalcohol. Palps dorsally speckled with light brown pig-mentation. Brown pigmentation also evident at basesof papillae. Staining of glandular areas particularlynoticeable on abdominal chaetigers as intense inter-parapodial patches and as large spots on the cuticularflaps of the anterior pouches. Short paired parallellines deeply stained, either side of mid-ventral groove,at level of each pair of abdominal parapodia. Addi-tional staining as speckled transverse bands dorsallyacross abdominal segments.Etymology: From the Latin meaning conversely, re-ferring to the presence of long prechaetal (rather thanpostchaetal) neuropodial lamellae on most thoracicchaetigers.Habitat: Found at four stations (Stn 2, 6, 8 and 52),in coarse sands and gravels, 26-42 m, to the east andnorthwest of Mahé (Fig. 1).Remarks: Magelona conversa new species belongsto a ’Magelona mirabilis group’ of species, all hav-ing a rounded prostomium, lacking frontal horns, andspatulate chaetae on chaetiger 9. There are 13 knownmembers of this group, including M. mirabilis (John-ston, 1865), M. johnstoni Fiege, Licher & Mackie,

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2000, M. crenulata Bolívar & Lana, 1986, M. pitelkaiHartman, 1944, M. sacculata Hartman, 1961, M. ri-ojai Jones, 1963, and two unnamed species (A andB) from the Gulf of Mexico (Uebelacker & Jones,1984). Indian Ocean-west Pacific members are M. ob-ockensis, M. heteropoda, M. pectinata, M. tinae andM. sachalinensis. Only two species, Magelona sp. Aand M. sachalinensis, resemble M. conversa in havingbidentate hooks. The new species differs from all 13 inhaving long neuropodial prechaetal lamellae on mostof the thoracic chaetigers.

Magelona falcifera new species (Fig. 3)Material examined: SE of Mahé, Stn 1a (4◦41.58′ S, 55◦ 32.20′ E), coarse sand, 22 m, 2paratypes (NMW.Z.2000.020.0008; 2af, f), VV2,7.03.00; Stn 2a (4◦ 42.97′ S, 55◦ 32.41′ E),coarse quartz, calcareous sand/gravel, 30 m, holo-type (NMW.Z.2000.020.0009; c) and 9 paratypes(NMW.Z.2000.020.0010; 1c, 8af, f), VV2, 7.03.00;Stn 2b (4◦ 42.96′ S, 55◦ 32.35′ E), coarsequartz, calcareous sand/gravel, 30 m, 5 para-types (NMW.Z.2000.020.00011; 5af, f), VV2,7.03.00.— NE of Mahé, Stn 5a (4◦ 34.78′ S,55◦ 33.17′ E), medium quartz sand, 35 m, 2paratypes (NMW.Z.2000.020.0012; 2af, f), VV2,8.03.00; Stn 6a (4◦ 36.97′ S, 55◦ 32.22′ E), me-dium/coarse calcareous sand, 25 m, 1 paratype(NMW.Z.2000.020.0013; af), VV2, 8.03.00; Stn 6b(4◦ 37.07′ S, 55◦ 32.27′ E), medium/coarse calcareoussand, 26 m, 8 paratypes (NMW.Z.2000.020.0014; 3c,5af, f), VV2, 8.03.00; Stn 39a (∼4◦ 38′ S, 55◦ 30′S), coarse calcareous sand, with fine sand, 11 m, 2paratypes (NMW.Z.2000.020.0015, 1c, 1af, f), VV2,20.03.00; Stn 39b (∼4◦ 38′ S, 55◦ 30′ E), coarsecalcareous sand, with fine sand, 10 m, 1 paratype(NMW.Z.2000.020.0016; af), VV2, 20.03.00.– W ofMahé, Stn 10d (4◦ 43.91′ S, 55◦ 20.27′ E), muddysand, 56m, 1 paratype (NMW.Z.2000.020.0017; af, f),VV2, 10.03.00.Diagnosis: Prostomium as long as or less than width,rounded subhexagonol, without prostomial horns,palps long. Thoracic chaetigers with lanceolate post-chaetal lamellae, prechaetal lamellae indistinct, lack-ing superior processes. Chaetigers 1–9 with capillarychaetae. Abdominal chaetigers with long lanceolatelamellae and one or two greatly enlarged hoodedhooks in anterior abdominal parapodia; other hoodedhooks bidentate, those nearest lateral lamellae smallerand more slender. Hooks arranged in two groups, vis-à-vis. Lateral pouches absent.

Description: A very slender species, slightly constric-ted at chaetiger 9, thorax-abdomen change indistinct.Holotype entire, thorax (including prostomium) 1.75mm long, 0.33 mm wide, total length 26 mm for 87chaetigers. Entire paratypes (5), 6–13 mm with 47–74chaetigers.

Prostomium as long as or less than width (L:Wratio 0.9–1.0), rounded subhexagonol, anterior mar-gin smooth and straight (Fig. 3A). Prostomium withtwo inconspicuous dorsal muscular ridges, prosto-mial horns and eyes absent. Proboscis globular, withsubtle ridges. Palps arise ventrolaterally from baseof prostomium, long; reaching around chaetiger 25,non-papillated basal region reaching around chaetiger3. Palps with long papillae, two rows either side ofventral groove. Only one specimen with palps retained(NMW.Z.2000.020.0010).

Peristomium achaetous, long, about twice lengthof first chaetiger. Chaetigers 1 – 8 with similar para-podia; prechaetal lamellae indistinct. Superior notopo-dial prechaetal processes (DML) and ventral neuropo-dial lobes (VNL) absent. Postchaetal lamellae lanceol-ate, about equal size in both rami, becoming graduallylonger and broader from chaetiger 1 to 8 (Fig. 3B–D).Chaetae of chaetigers 1–8 all bilimbate capillaries.

Chaetiger 9: segment slightly shorter and nar-rower than preceding ones. Prechaetal lamellae low,indistinct. Neuropodial postchaetal lamellae broadlyrounded with short narrow tip, notopodial postchaetallamellae narrower (Fig. 3E). Chaetae as on chaetigers1–8.

Anterior abdominal chaetigers with long, basallyconstricted, lanceolate lateral lamellae; about equalsize in both rami (Fig. 3F, G), becoming more slenderon median (Fig. 3H), and then digitiform on pos-terior (Fig. 3I), chaetigers. Lamellae not extendingpostchaetally; no prechaetal lamellae. Small triangularprocesses (DML & VML) evident throughout at innermargins of chaetal rows, decreasing in size posteriorly(papilliform on posteriormost chaetigers). Lamellaebasally supported by 2–3 slender and inconspicuousaciculae, arising from distal regions of the single broadcrescentic structures (sheaths?) that occupy interramalregions. Lateral pouches absent. Pygidium small withtwo slender lateral anal cirri (Fig. 2M).

Large sickle-shaped hooded hooks (one, rarelytwo) in both rami of anterior abdominal chaetigers(for 10–15 segments). Crests of largest hooks smooth,lacking secondary teeth (Fig. 3K). Smaller enlargedhooks also on chaetiger 10 and following last chaeti-ger having large hooks (i.e. after chaetiger 20–25).

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Figure 3. Magelona falcifera n. sp. (A–B, H–M paratype, NMW.Z.2000.020.0014; C–G paratype, NMW.Z.2000.020.0011). (A) Anteriorregion, dorsal view; (B–E) Chaetigers 1, 6, 8 and 9, anterior views; (F–I) Chaetigers 11, 22, 39 and 54, anterior views (aciculae not shown);(J) Small enlarged hooded hook, chaetiger 10; (K) Large sickle-shaped hooded hooks, chaetiger 12; (L) Hooded hook, median chaetiger; M.Posterior region, dorsal view.

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These hooks bidentate, with small secondary teeth(Fig. 2J), intermediate between largest hooks and‘ordinary’ bidentate hooks (Fig. 3L). Single hoodedhooks nearest lateral lamellae (and in anterior abdo-men next to enlarged hooks) smaller and more slenderthan ‘ordinary’ bidentate hooks. Hooks arranged intwo groups, vis-à-vis (Fig. 3F–I). In posterior abdo-men, tridentate hooks (parallel secondary teeth abovemain fang) occur sporadically.Colour: No living animals observed, all specimensstained with Rose Bengal. Intense staining of glandu-lar areas particularly noticeable in dorsal and ventralpatches on thoracic chaetigers and laterally, betweenparapodia, in abdomen.Etymology: From the Latin meaning ‘bearing sickles’,referring to the large sickle-shaped hooded hooks onthe anterior abdominal chaetigers.Habitat: Found at six stations (Stn 1, 2, 5, 6, 10 and39), in predominantly coarse sands, 10–56 m, off theeast and west coasts of Mahé (Fig. 1).Remarks: In possessing enlarged abdominal hooks,Magelona falcifera new species resembles three spe-cies from the Gulf of Mexico: Magelona sp. Cof Uebelacker & Jones (1984), Meredithia spi-nifera Hernández-Alcántara & Solís-Weiss, 2000and Meredithia uebelackerae Hernández-Alcántara &Solís-Weiss, 2000. The strongly curved enlargedhooks of the new species have the same form as de-scribed for Magelona sp. C and Meredithia uebelack-erae; Meredithia spinifera possesses weakly curvedspine-like hooks. The new species is also readilydistinguished from both Meredithia species in com-pletely lacking prostomial horns (see ‘Discussion’).Magelona falcifera shares most morphological fea-tures with Magelona sp. C, but differs in lackingsecondary teeth on the largest hooks and in possessingsmall processes (DML & VML) at the inner marginsof the chaetal rows on all (not just anterior) abdominalsegments.

Magelona gemmata new species (Fig. 4)Material examined: Seychelles: NW of Mahé, Stn7a (4◦ 33.10′ S, 55◦ 17.30′ E), muddy quartz sand,62 m, 1 juvenile paratype (NMW.Z.2000.020.0018;af, f), VV2, 9.03.00.— W of Mahé, Stn 10a (4◦44.05′ S, 55◦ 20.54′ E), muddy sand, 55m, holotype(NMW.Z.2000.020.0019; af, f), VV2, 10.03.00; Stn11c (4◦ 44.32′ S, 55◦ 24.83′ E), coarse quartz sand,48m, 2 paratypes (NMW.Z.2000.020.0020; 2af, f),VV2, 10.03.00.Diagnosis: Prostomium longer than wide, subrect-

angular, with distinct frontal horns. Notopodia ofchaetigers 1–8 with subspatulate postchaetal lamel-lae, inferiorly encircling chaetae to form low trian-gular prechaetal lamellar regions; superior prechaetalprocesses (DML) present. Neuropodia of chaetigers1–7 with slender cirriform ventral neuropodial lobes(VNL), pre- and postchaetal lamellae not developed.Neuropodia of chaetigers 8 and 9 with subtriangu-lar postchaetal lamellae and cirriform ventral neuro-podial lobes (VNL). Notopodia of chaetiger 9 withdistally swollen subtriangular postchaetal lamellae.All thoracic chaetae capillary. Postchaetal lamellae inanterior abdomen only, separated from spatulate lat-eral lamellae by distinct notch. Abdominal hoodedhooks tridentate, in two groups, vis-à-vis. Lateralpouches (C configuration) present posteriorly.Description: A slender species, slightly constrictedat chaetiger 9. Holotype posteriorly incomplete, intwo fragments; thorax (including prostomium) 4.4 mmlong, 0.8 mm wide, body length 26.5 mm for 55 (49 +6) chaetigers.

Prostomium longer than wide (L:W ratio 1.1–1.3),anterior margin triangular and smooth, with distinctfrontal horns (Fig. 4A). Four prominent dorsal longit-udinal muscular ridges, inner pair joined for majorityof length, divergent tips extending into frontal horns;no eyes. Proboscis globular, with distinct ridges.Palps arising ventrolaterally from base of prostomium,reaching chaetiger 15–18, non-papillated basal regionreaching about chaetiger 4. Palp papillae arranged insix rows proximally, four rows medially and two rowsdistally; rows equally divided either side of ventralgroove.

Peristomium achaetous, about equal length tofirst chaetiger. Notopodia of chaetigers 1–8 similar,with subspatulate postchaetal lamellae that inferiorlyencircle chaetae, forming low triangular prechaetallamellar regions; superiorly, long digitiform pre-chaetal processes (DML) present (Fig. 4B–D). Neuro-podia of chaetigers 1–7 all similar, with long cirriformventral neuropodial lobes (VNL), pre- and postchaetallamellae not developed. Neuropodia of chaetiger 8with rounded subtriangular postchaetal lamellae andcirriform ventral neuropodial lobes.

Chaetiger 9: segment shorter and narrower thanpreceding ones. Notopodial postchaetal lamellaesmaller than those of chaetigers 2–8. Lamellae sub-triangular with swollen bud-like tips, inferiorly en-circling chaetae forming low triangular prechaetal re-gions (Fig. 4E), superior prechaetal processes absent.Neuropodial postchaetal lamellae similar to those of

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Figure 4. Magelona gemmata n. sp. (holotype). (A) Anterior region, dorsal view; (B–E) Chaetigers 1, 6, 8 and 9, anterior views; (F–G)Chaetigers 10 and 49, anterior views (aciculae not shown); (H) Tridentate hooded hooks, abdomen, lateral views; (I) Hooded hook, obliquefrontal view, (J) Hooded hook, oblique rear view.

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chaetiger 8, but more pointed. Ventral neuropodiallobes in obvious prechaetal positions. All thoracicchaetae capillary.

Abdomen: chaetigers 10–18 shorter than follow-ing ones; with large spatulate lateral lamellae in bothrami, becoming smaller and more rounded on mediansegments (Fig. 4F, G). Lateral lamellae basally suppor-ted by about 6 slender curved aciculae. Small roundedpostchaetal lamellae in anterior abdomen only, separ-ated from lateral lamellae by distinct notch. Small tri-angular processes (DML & VML) evident throughoutat inner margins of chaetal rows. Small paired posteri-orly open lateral pouches (C configuration) on eachsegment from chaetiger 42, just anterior to parapodia.Pygidium not known.

Abdominal hooded hooks tridentate, in twogroups, vis-à-vis (Fig. 4F, G). Each hook similar insize (Fig. 4H), with parallel secondary teeth abovemain fang (Fig. 4I, J).Colour: No live specimens observed and all speci-mens stained with Rose Bengal. Staining most intenseon glandular tissue, which is noticeably abundant inthis species. Heavy staining occurs as transverse bandsacross the dorsal surfaces of the thorax and abdomen,interparapodially in the abdomen and on the anteriorabdominal lamellae.Etymology: From the Latin meaning ‘with buds’, re-ferring to the swollen bud-like tips of the notopodialpostchaetal lamellae of chaetiger 9.Habitat: Found at three stations (Stn 7, 10 and 11), inmuddy sand to coarse quartz sand (48–62 m) off thewestern coast of Mahé (Fig. 1).Remarks: Magelona gemmata belongs to a ‘Magelonalongicornis group’ of species, all having well-developed frontal horns, lanceolate thoracic noto-podial postchaetal lamellae that basally encircle thechaetae, ventral neuropodial lobes, and essentiallysimilar capillary chaetae on all thoracic chaetigers.There are 11 clear members of this group, includ-ing M. longicornis Johnson, 1901, M. berkeleyiJones, 1971, M. pacifica Monro, 1933, M. annu-lata Hartmann-Schröder, 1962, M. nonatoi Bolívar &Lana, 1986, and four unnamed species (E, J, L andG) from the Gulf of Mexico (Uebelacker & Jones,1984). Indian Ocean-west Pacific members are M. len-ticulata and M. petersenae. Several additional speciesapproach these species (e.g., M. dakini Jones, 1978,M. hobsonae Jones, 1978 and Magelona sp. F ofUebelacker & Jones) but lack distinct frontal horns.

Five species (M. pacifica, M. nonatoi, andMagelona spp. G, J and L) also have thoracic

postchaetal neuropodial lamellae. However, onlyMagelona sp. G and Magelona sp. J have these solelyon chaetigers 8 and 9 – as in M. gemmata. The newspecies resembles Magelona sp. G in having posteriorlateral pouches, but differs in the possession of trident-ate (vs. bidentate) abdominal hooks. Tridentate hooksoccur in both Magelona sp. J and M. gemmata, but thenew species differs in having lateral pouches and lack-ing superior prechaetal processes on chaetiger 9. Theswollen bud-like tips found on the notopodial lamellae(chaetiger 9) of M. gemmata have not previously beendescribed for any other magelonid.

Discussion

The discovery of Magelona falcifera new species fo-cuses attention on generic delimitations within theMagelonidae. Until 2000, when Hernández-Alcántara& Solís-Weiss introduced Meredithia, the only re-cognised genus was Magelona F. Müller, 1858. Allpreviously introduced generic names (Maea Johnston,1865; Rhynophylla Carrington, 1865) had been syn-onymised with Magelona. The only feature describedas distinguishing Meredithia was the presence of en-larged abdominal hooks, although both described spe-cies additionally had frontal horns; a variable characterin Magelona.

The new species described herein and Magelonasp. C of Uebelacker & Jones (1984) do differ fromthe original diagnosis of Meredithia in lacking frontalhorns, while also possessing enlarged hooks. The pres-ence of large hooks, of size and form intermediatebetween the largest hooks and the ‘ordinary’ hoodedhooks, in these two species forces us to question thevalidity of Meredithia. At this time, there seems tobe no reason why enlarged hooks, rather than othercharacters (e.g., spatulate chaetae, prostomial horns orlateral pouches), should be used to separate genera inthe Magelonidae. A detailed cladistic analysis (Brasil,pers. com.) is in preparation and may yield strongerevidence for recognising other genera within the fam-ily. Until then, we prefer to follow Uebelacker & Jones(1984) and include species with enlarged hooks inMagelona.

Recently, Aguirrezabalaga et al. (2001) have erec-ted another genus, Octomagelona. The single spe-cies, O. bizkaiensis Aguirrezabalaga, Ceberio & Fiege,2001, possesses only eight thoracic chaetigers; allother magelonids have nine. Again, a detailed cladistic

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analysis of magelonids would be useful in evaluatingwhere generic delineations lie.

In this paper, we have consciously described para-podial structures according to their appearance and po-sition (i.e. prechaetal, postchaetal, superior, inferior)rather than use the terminology introduced and mod-ified by Jones (1963, 1971, 1978). Thus terms suchas ‘dorsal medial lobe’ (DML, in thorax and abdo-men), ventral medial lobe’ (VML, mainly in abdomen,sometimes in thorax), ventral neuropodial lobe (VNL,thorax), and interlamellae have been avoided whereverpossible.

Jones (1963) first introduced ‘medial lamellae’ asa descriptive term for the superior notopodial and in-ferior neuropodial processes that follow the abdominalhooks. This avoided the use of the different posi-tional adjectives, while emphasising the horizontalsymmetry of the rami. The term was subsequentlymodified and subdivided (Jones, 1971) into the DML,VML and VNL summarised above. From their es-tablishment, the distinction between the use of VMLand VNL was rather vague, particularly in the pos-terior thorax. Nateewathana & Hylleberg (1991) triedto clarify matters in the thoracic neuropodia by treat-ing the ventral neuropodia in relation to prechaetal,postchaetal and ‘infrachaetal (as infrasetal)’ parts.The third term was nevertheless imprecise and incon-sistently applied for inferior prechaetal, inferior, orpostchaetal processes/lamellae (Nateewathana & Hyl-leberg, 1991; Figs 2E–F, 3F and 4C–D) and VML wasalso used in some cases (Fig. 6E–F; see also Jones,1971: 1446, Figs 33–35 vs. 36)! Jones (1971) acknow-ledged problems with the terminology and, in relationto the VNL, often stated their position; for example, inJones (1978) they were mostly described as prechaetalor ventral, occasionally (p. 349) postchaetal.

The situation in relation to the DML and VMLprocesses in the abdomen is less contentious; how-ever, if these were to be regarded as homologous withthe same named processes in the thorax, they wouldbe prechaetal – though obvious prechaetal structuresare rudimentary or absent. In a number of species,the abdominal lateral lamellae arise behind the hoodedhooks, suggesting that these may be postchaetal struc-tures. The portion immediately behind the chaetaemay be partially or completely separated (the so-called‘interlamellae’) from the lateral lamellae, or may beabsent completely.

In view of the confusion in standardising or inter-preting the terminology, we recommend that it eitherbe abandoned, or always qualified by positional in-

formation. The greatest problem with its continued useis that it encourages synoptic descriptions, rather thandetailed examinations of all the morphological struc-tures present (e.g., many descriptions provide littleor no details regarding prechaetal lamellae). Withoutsuch information more detailed assessments of rela-tionships within the Magelonidae will be difficult toachieve.

Acknowledgements

We acknowledge: the staff of the Shoals of Capricornprogramme, including Martin Callow, Jan Robinsonand Caroline Lawton, for their logistical help in theSeychelles; John Collie and the staff at the SeychellesMarine Parks Authority (MPA) for use of their facil-ities; the Seychelles Fisheries Authority, especiallyCaptain Gerrard Ernesta and the crew of the R.V.L’Amitié for their expertise and enthusiasm in col-lecting the offshore samples; BioSyB staff for helpin collecting and sorting samples; Mairi Best (Uni-versity of Chicago) for assistance on L’Amitié; JonHoughton (University of Wales, Swansea) for feedingus all; and the National Museum of Wales for fundingthe expedition.

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