Hydrobiologia 496: 191–197, 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.

191

A new genus of Syllidae (Polychaeta) from Western Australia

Guillermo San Martın & Eduardo LopezLaboratorio de Biologıa Marina e Invertebrados, Departamento de Biologıa (Zoologıa),Facultad de Ciencias, Universidad Autonoma de Madrid, Canto Blanco, 28049 Madrid, SpainE-mail: guillermo.sanmartin@uam.es

Key words: taxonomy, Annelida, Polychaeta, Syllidae, new genus

Abstract

During a study carried out on the subfamily Exogoninae (Syllidae) from Australia, several specimens of a newgenus and species were found in samples of dead coral substrate from Western Australia. They have long palps,fused except for a terminal notch, long median and two short lateral antennae, a single pair of short tentacularcirri, and short dorsal cirri, somewhat longer than the parapodial lobes. These characters resemble those of thegenus Exogone Örsted, 1845. However, all these appendages are articulated. The chaetae are very similar to thoseof several species of Syllis Lamarck, 1818, having coarse spines on the margin of compound chaetal blades andtruncated dorsal simple chaetae. Furthermore, the pharynx begins in chaetiger 3, posterior to the peristomium, asin many species of the genus Syllis; this condition does not occur in any described species of Exogone. The newgenus is provisionally proposed to belong to the subfamily Syllinae, although it has some characters typical of theExogoninae. Examination under the SEM shows another peculiar feature, the nuchal organs are distinctly laterallylocated. Within the Syllinae, only Paratyposyllis Hartmann-Schröder, 1962 has a single pair of tentacular cirri, butin that genus, the palps are only basally fused.

Introduction

Major contributions to the Australian Syllidae dateback to Haswell (1886, 1920a, b) and Augener (1913,1927). More recently, Hartmann-Schröder (1979,1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987,1989, 1990, 1991), Hutchings & Rainer (1979, 1980),Hutchings & Murray (1984), and San Martín & López(1998) and San Martín (2002) have described manyadditional species. Glasby (2000) summarised all as-pects of the family, with particular reference to theAustralian species.

During a recent stay in the Australian Museum,the senior author started a study of the Syllidae fromAustralia. The first subfamily studied was the Exo-goninae. Over the years, members of the museumstaff have amassed large collections of unidentifiedexogonins from all around Australia. Among thesespecimens, several of a very peculiar species wereisolated, all having characters resembling the genusExogone Örsted, 1845 namely palps fused all alongtheir length except for a terminal notch, a single pair of

tentacular cirri, and short dorsal cirri. However, theirantennae, tentacular and dorsal cirri were articulated,and their chaetae were very similar to those of somespecies of Syllis Lamarck, 1818. No syllid genus orspecies is known to have this combination of charac-ters, therefore we establish a new genus and a newspecies for the specimens. The position of this enig-matic new genus in relation to the currently recognisedsubfamilies is also examined.

Materials and methods

All specimens were collected from Goss Passage,Abrolhos Islands, Western Australia, in dead coralsubstrate, between 4 and 30 m depth, using SCUBA,by Pat Hutchings and C. Bryce.

The specimens were examined using both dissect-ing and compound light microscopes. The latter wasequipped with interference contrast optics (Nomarsky)and a camera lucida drawing tube. Body width wasmeasured across the proventriculus and does not in-

192

clude parapodial lobes. Two specimens were driedat critical point and subsequently coated with 300Å of gold for Scanning Electron Microscope (SEM)examination at the Servicio Interdepartamental de In-vestigación (SIdI), Universidad Autónoma de Mad-rid. After study, all other specimens were stored in70% ethanol and deposited in the Australian Museum(AM).

Systematic account

Family Syllidae Grube, 1850Subfamily Syllinae Grube, 1850Genus Karroonsyllis n. gen.Diagnosis: Body of meiofaunal size, slender, cyl-indrical, with numerous segments. Prostomium withtwo pairs of eyes and a pair of anterior ocular spots;three articulated antennae. Palps long and broad, fusedall along their length, except for a terminal notch.Tentacular segment similar to following ones, with asingle pair of articulated tentacular cirri; nuchal organsas a ciliated groove in ventrolateral position. Segmentswithout ciliary bands. Dorsal cirri on all segments,articulated, with few articles. Parapodia each with sev-eral compound chaetae, and simple dorsal and ventralcapillary chaetae on posterior parapodia. Two analcirri, similar to dorsal cirri. Pharynx with a singledorsal conical tooth and a crown of soft papillae, be-ginning on segment 4–5.Remarks: Karroonsyllis n. gen. has a mixture of thecharacters typical of the subfamilies Exogoninae andSyllinae. The fused palps, single pair of tentacularcirri and short dorsal cirri are indicative of the former,whereas the articulated antennae, tentacular cirri anddorsal cirri are commonly found in the latter. An affin-ity with the Syllinae is also suggested by both simpleand compound chaetae having the same form as thosefound in some Syllis. Furthermore, the beginning ofthe pharynx is located in segment 4 or 5, as occursin some Syllis species. In species of Exogone (Exo-goninae), it is always located in the peristomium orchaetiger 1. Karroonsyllis n. gen. is established onthe basis of its unusual combination of characters. Thesystematic position of the genus is discussed below,following the detailed species description.Etymology: The name of the genus is derived from theAustralian aboriginal word ‘Karroon’, which means‘deformed’ (Endacott, 1973), and Syllis.

Karroonsyllis exogoneformis n. sp. (Figs 1–3)Material examined: Western Australia, Abrolhos Is-

lands: Goss Passage, Southeast end of Long Island,28◦ 28.8′ S, 113◦ 46.5′ E, dead coral substrate embed-ded in calcareous substrate, 30 m, 22.05.1994, holo-type (AM W26500), and 5 paratypes (AM W26501).Goss Passage, Beacon Island, 28◦ 25.5′ S, 113◦ 47′E, dead coral plates covered in coralline algae, 8 m,22.05.1994, 7 paratypes (AM W26502). Goss Pas-sage, North end of Long Island, 28◦ 28.3′ S, 113◦ 46.3′E, dead coral covered with coralline algae and boringbivalves, 8 m depth, 22.05.1994 (22.05.1994 instead),2 paratypes (AM W26503). North East entrance toGoss Passage, 28◦ 27.9′ S, 113◦ 46.7′ E, dead Acro-pora, coralline and brown algae on coral substrate, 24m depth, 22.05.1994, 3 paratypes (AM W26504) and6 paratypes (AM 26505). North end of Long Island,28◦ 27.9′ S, 113◦ 46.3′ E, dead coral substrate withcoralline and brown algae, 6 m depth, 22. 05.1994, 1paratype (AM W27096). Off South end of Long Is-land, Beacon Island, 28◦ 28.8′ S, 113◦ 46.3′ E, deadcoral substrate covered in coralline algae, 5 m depth,25.05.1994, 2 paratypes (AM W27097) and 1 paratype(AM W27144).Description: Body long and slender. Holotype com-plete, 6 mm long, 0.2 mm wide, for 48 chaetigers;without colour markings. Largest paratype 7 mmlong, 0.23 mm wide, for 55 chaetigers, mid-body andposterior segments clearly defined by intersegmentalconstrictions. Prostomium (Fig. 1A, B) oval to sub-pentagonal, wider than long with four small eyes intrapezoidal arrangement and one pair of anterior eyes-pots, sometimes not perceptible. Antennae moderatelylong and articulated; median antenna originating inmiddle of prostomium, twice as long as prostomiumand palps together, with 12–13 articles, 3–4 basalarticles more or less indistinct; lateral antennae ori-ginating near anterior pair of eyes, much shorter thanmedian antenna, similar in length to palps, with 5–9articles. Palps (Figs 1A, B and 2A) long, about 1.5–2times length of prostomium, dorsally fused all alongtheir length except for a small distal notch. Nuchalorgans ventrolatery located (Fig. 2A), as ciliate ridgesprotected by lips (Fig. 2B).

Tentacular segment well-developed, similar inlength to following ones; one pair of tentacular cirri,shorter than lateral antennae, with 3–4 articles (Fig.1A, B). Dorsal cirri (Figs 1A–D and 2C) short and ar-ticulated, somewhat longer than parapodial lobes, with2–5 articles, distal article usually longer and widerthan others, somewhat swollen. Parapodial lobes (Figs1D and 2C) conical, distally rounded; ventral cirri

193

Figure 1. (A) Anterior end, dorsal view (holotype). (B) Anterior end, dorsal view (paratype). (C) Posterior end, dorsal view (paratype). (D)Midbody parapodium (paratype). (E) Compound chaetae, anterior parapodium (holotype). (F) Dorsal simple chaeta (holotype). (G) Ventralchaeta (holotype). (H) Acicula (holotype). (I) Compound chaetae, posterior parapodium (holotype). Scale: A–C = 0.1 mm; D = 50 µm; E–I =20 µm.

(Figs 1D and 2C) digitiform, slightly longer thanparapodial lobes.

Anterior parapodia each with about six hetero-gomph compound chaetae (Figs 1E and 3A–C); shaftheads smooth or with a few slender spines. Chaetal

blades distinctly bidentate, booth teeth similar in sizeand shape, with coarse, moderately long spines alongmargin. Blade lengths grade progressively from 18µm above to 7.5 µm below. Middle and posteriorchaetigers also with about six heterogomph compound

194

Figure 2. SEM micrographs. (A) Anterior end, ventrolatral view, showing nuchal organs. (B) Detail of nuchal organ. (C) Midbody parapodium,showing dorsal and ventral cirri. (D) Posterior parapodium, showing dorsal simple and compound chaetae.

chaetae on each parapodium (Figs 1I and 2D), butblades bearing coarser serrations and shafts with dis-tinct spines. Blades of dorsalmost compound chaeta(Figs 1I, 2D and 3E) distinctly longer than others,about 24 µm long, with distal tooth markedly roun-ded and slightly expanded (Fig. 3E). Blades of otherfive compound chaetae show similar gradation to thoseof anterior parapodia. More dorsal blade (Figs 1I and3E) 15 µm long, with small subdistal tooth and lar-ger, somewhat rounded distal one. Ventralmost blade(Figs 1I and 3F) 9 µm long, with both teeth robustand approximately similar in size; distal one slightlymore acute. Solitary dorsal simple chaetae (Figs 1F,2D and 3D) from mid-body, truncate, subdistal marginwith several rows of coarse spines (Fig. 3D). Solitaryventral simple chaetae (Fig. 1G) on posterior para-podia, slender, sigmoid, bidentate, smooth. Solitary

acicula (Fig. 1H) in all parapodia, distally rounded,with somewhat hollow tip.

Pharynx (Fig.1A) extending from chaetiger 3–4 to7–8; pharyngeal tooth large, near anterior margin, sur-rounded by a crown of soft papillae. Proventriculusshorter than pharynx, extending through two seg-ments, with about 24 muscle cell rows.

Pygidium (Fig. 1C) triangular, distally rounded,with a pair of anal cirri, similar in length and shapeto dorsal cirri, with 2–3 articles.Etymology: The specific name refers to the similar-ity with the genus Exogone (exogoneformis= shape ofExogone)Remarks: Karoonsyllis exogoneformis has truncatedorsal simple chaetae and bidentate compound chaetaewith coarse marginal spines on the blades. Thesechaetal forms are very similar to those found in sev-eral species of Syllis, namely Syllis amica Quatref-

195

Figure 3. SEM micrographs. (A) Dorsalmost compound chaeta, anterior parapodium. (B) medium size compound chaeta, anterior parapodium.(C) Ventral compound chaeta, anterior parapodium. (D) Tip of dorsal simple chaeta, posterior parapodium. (E) Two dorsalmost compoundchaetae, posterior parapodium, in posterior view. (F) Ventralmost compound chaeta, posterior parapodium.

196

ages, 1866, S. rosea (Langerhans, 1879), S. pectin-ans Haswell, 1920, S. kabilica Ben-Eliahu, 1977, S.pulvinata (Langerhans, 1881), S. gerlachi (Hartmann-Schröder, 1960) and others (San Martín, in press). Therelationship between these species is, as yet, untestedby any phylogenetic analysis.

Discussion

Unfortunately, no specimens were in a reproduct-ive state, which could be very informative as to thesystematic position of Karroonsyllis n. gen.

All the genera of the Subfamily Syllinae have twopairs of tentacular cirri, with the exception of twopoorly known genera, Reductotyposyllis Hartmann-Schröder, 1974, from African coasts, without tentacu-lar cirri, and Paratyposyllis Hartmann-Schröder, 1962,from Chile, with a single pair (see Hartmann-Schröder, 1962, 1974). However, none of these generahas fused palps, although both show a noticeable re-duction in size of the dorsal cirri. The systematicposition of the new genus is uncertain, because it hasa mixture of characters of two subfamilies, the Syl-linae Grube, 1850 and the Exogoninae Langerhans,1879. Provisionally, we are placing it in the subfam-ily Syllinae, because its articulated antennae and cirri,simple and compound chaetae and pharyngeal char-acters. However, a new classification of the wholefamily, based on cladistic methods, is necessary.

Acknowledgements

We wish to express our gratitude to the Australian Mu-seum for the research fellowship which enabled thesenior author to study their collections. This gratitudeis especially extended to all the staff of the Departmentof Marine Invertebrates for their help and friendship;furthermore, Kate Attwood and Anna Murray facilit-ated the study by sorting the material and extractingthe specimens for examination, and Penny Berentsmanaged the collections. Dr Pat Hutchings and ananonymous referee, as well as Editors of the Con-ference offered useful advices and helped us reviseand improve the English text of the manuscript. Thepublication of this paper has been possible by a grant(Acción Especial PGC2000-2919-E) of the Ministeriode Ciencia y Tecnología, Spain, as well as founds ofour own University.

References

Augener, H., 1913. Polychaeta I, Errantia. Die Fauna Südwest-Aust.Ergebnisse des Hamburger Südwest-australischen Forschungre-ise 1905, 4: 65–304.

Augener, H., 1927. Polychaeten von Südost- und Süd-Australien.Papers from Dr. Th. Mortensen’s Pacific Expedition 1914-16.XXXVIII, 34. Vidensk. Meddr. dansk naturh. Foren. 83: 71–275.

Endacott, S. J., 1973. Australian Aboriginal Words and Place Namesand Their Meanings. 10th Edition. Acacia Press, Melbourne. 64pp.

Glasby, C., 2000. Family Syllidae. In Beesley, P. L., G. J. B. Ross& C. J. Glasby (eds), Polychaetes & Allies: The Southern Syn-thesis. Fauna of Australia. Vol. 4a Polychaeta, Myzostomida, Po-gonophora, Echiura, Sipuncula. CSIRO Publishing: Melbourne:161–167.

Hartmann-Schröder, G., 1962. Zur Kenntnis des Eulitorals derchilenischen Pazifikküste und der argenstinischen Küste Süd-patagoniens unter besonderer Berücksichtigung der Polychaetenund Ostracoden. Teil II. Die Polychaeten des Eulitorals. Mitt.hamb. zool. Mus. Inst. 60 (Suppl. vol.): 57–169.

Hartmann-Schröder, G., 1974. Zur Kenntnis des Eulitorals derafrikanischen Westküste zwischen Angola und Kap der GutenHoffnung und der afrikanischen Ostküste von Südafrika undMocambique unter besonder Berücksichtigung der Polychaetenund Ostracoden. Die Polychaeten des Untersuchungebietes. Mitt.hamb. zool. Mus. Inst. 69: 95–228.

Hartmann-Schröder, G., 1979. Teil 2. Die Polychaeten der tropis-chen Nordwestküste Australiens (Zwischen Port Samson inNorden und Port Hedland in Süden). Mitt. hamb. zool. Mus. Inst.76: 75–218.

Hartmann-Schröder, G., 1980. Teil 4. Die Polychaeten der tropis-chen Nordwestküste Australiens (Zwischen Port Samson inNorden und Exmouth im Süden). Mitt. hamb. zool. Mus. Inst.77: 41–110.

Hartmann-Schröder, G., 1981. Teil 6. Die Polychaeten der tropisch-subtropischen Westküste Australiens (zwischen Exmouth inNorden und Cervantes im Süden). Mitt. hamb. zool. Mus. Inst.78: 19–96.

Hartmann-Schröder, G., 1982. Teil 8. Die Polychaeten dersubtropischen-antiborealen Westküste Australiens (ZwischenCervantes im Norden und Cape Naturaliste im Süden). Mitt.hamb. zool. Mus. Inst. 79: 51–118.

Hartmann-Schröder, G., 1983. Teil 9. Die Polychaeten der anti-borealen Südwestküste Australiens (zwischen Dunsborough imNorden und Denmark im Süden). Mitt. hamb. zool. Mus. Inst.80: 123–167.

Hartmann-Schröder, G., 1984. Teil 10. Die Polychaeten der anti-borealen Südküste Australiens (Zwischen Albany im Westen unCeduna im Osten). Mitt. hamb. zool. Mus. Inst. 81: 7–62.

Hartmann-Schröder, G., 1985. Teil 11. Die Polychaeten der an-tiborealen Südküste Australiens (zwischen Port Lincoln imWesten und Port Augusta im Osten). Mitt. hamb. zool. Mus. Inst.82: 61–99.

Hartmann-Schröder, G., 1986. Teil 12. Die Polychaeten der anti-borealen Südküste Australiens (zwischen Wallaroo im Westenund Port MacDonnell im Osten). Mitt. hamb. zool. Mus. Inst.83: 31–70.

Hartmann-Schröder, G., 1987. Teil 13. Die Polychaeten der anti-borealen Küste von Victoria (Australien) (zwischen Warrnam-bool im Westen und Port Welshpool im Osten). Mitt. hamb. zool.Mus. Inst. 84: 27–66.

Hartmann-Schröder, G., 1989. Teil 14. Die Polychaeten der an-tiborealen und subtropisch-tropischen Küste Südost-Australien

197

zwischen Lakes Entrance (Victoria) im Süden und Maclean(New South Wales) im Norden. Mitt. hamb. zool. Mus. Inst. 86:11–63.

Hartmann-Schröder, G., 1990. Teil 15. Die Polychaeten dersubtropisch-tropischen und tropischen Ostküste Australienszwischen Lake Macquarie (New South Wales) im Süden undGladstone (Queensland) im Norden. Mitt. hamb. zool. Mus. Inst.87: 41–87.

Hartmann-Schröder, G., 1991. Teil 16. Die Polychaeten dersubtropisch-tropischen bis tropischen Ostküste Australiens zwis-chen Maclean (New South Wales) und Gladstone (Queensland)sowie von Heron Island (Groβes Barriere-Riff). Mitt. hamb.zool. Mus. Inst. 88: 17–71.

Haswell, W. A., 1886. Observations on some Australian Polychaeta.Part I. Syllidae. Proc. linn. Soc. NSW. 10: 733–756.

Haswell, W. A., 1920a. The Exogonea. Proc. linn. Soc. NSW. 45:90–112.

Haswell, W. A., 1920b. Australian Syllidae, Eusyllidae and Auto-lytidae. Proc. linn. Soc. NSW. 45: 90–112.

Hutchings, P. & A. Murray, 1984. Taxonomy of polychaetes fromthe Hawkesbury River and the southern estuaries of New SouthWales, Australia. Rec. Aust. Mus. 36, suppl. 3: 1–118.

Hutchings, P. & S. Rainer, 1979. The polychaete fauna of CareelBay, Pittwater, New South Wales, Australia. J. Nat. Hist. 13:745–796.

Hutchings, P. & S. Rainer, 1980. A Key to Estuarine Polychaetes inNew South Wales. Proc. linn. Soc. NSW. 104: 35–48.

San Martín, G., 2002. A new genus and species of Syllidae (Poly-chaeta) from Australia brooding eggs dorsally by means ofcompound notochaetae. Proc. biol. Soc. Wash. 115: 333–340.

San Martín, G., In press. Anélidos Poliquetos. Familia SyllidaeGrube, 1850. In Ramos, M. A. et al. (eds), Fauna Ibérica, MuseoNacional de Ciencias Naturales. CSIC. Madrid, Spain.

San Martín, G. & E. López, 1998. Description of a new speciesof Sphaerosyllis from Australia and New Zealand (Polychaeta:Syllidae: Exogoninae). Proc. biol. Soc. Wash. 111: 241–245.