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Antarctic Science 11 (4):430-435 (1999) 0 British Antarctic Survey Printed in the United Kingdom

Rediscovery of the Antarctic species Sipho gaini Lamy, 1910 (Gastropoda: Neogastropoda) with remarks on its taxonomic position
YURl 1. KANTOR', and M.G. HARASEWYCH**
'A N Severtzov Institute ofProblems of Evolution, Russian Academy of Sciences, Leninsh prospect 33, Moscow I1 7071, RuJAia 'Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-01 18 IJSA *correApondingauthor

Abstract: Examination of the holotype of Sipho gaini Lamy, 1910, attributed by recent authors to the genus Chlanidota (Buccinulidae),revealed that this speciesbelongs to the genusBeluturricula and is a senior synonym of Belaturricula antarctica Dell, 1990. A redescription of the shell, anterior alimentary system, and radular morphology of Beluturricula gaini is provided. The genus Belaturricula is transferred to the family Conidae (sensu Taylor et al. 1993)on the basis of its radula, which is composed of hollow marginal teeth. The presence of a large shell, prominent operculum, acinous salivary glands, radular teeth with narrow bases in B. gaini, as well as the absence of buccal lips and rhyncodeal introvert, all indicate af5nities with the conid subfamily Clathurellinae. Because the radula ofPontiothaumuergata Hedley (19 16) is nearly indistinguishablefrom that of Belaturricula guini, we reassign Hedley's species to the genus Belaturricula as Beluturricula ergata (Hedley, 1916).
Received 11 November 1998. accepted 12 July 1999

Key words: bathyal, benthos, Conidae, Gastropoda, Mollusca, Scotia Plate, systematics Introduction
Siphogaini Lamy, 1910, was described on the basis of a single specimen collected off the South Shetland Islands. Thiele (19 12) provisionally included this species when describing thegenus Prosipho. More recently,S. guini has beenassigned to the related genus Chlanidota Martens, 1878, by Powell (1951) and Carcelles (1953). Dell (1990) referred to Chlanidotagarni as a species ofuncertainaffinity known only from its holotype. This species has not been illustrated since Lamy (19 11)figuredthe holotype, and there have been no new records or findings of this taxon reported since the original description. In the course of a revision of the genus Chlanidota (Harasewych & Kantor 1999), we were able to examine the holotype ofSiphoguini as well as severaladditional specimens collected by the United StatesAntarctic Program (USAP)and the Alfred-Wegener-Institut fur Polar- und Meeresforschung (RV Polurstern, Cruise ANT XIV/2). The anatomy and radular morphology clearly indicate that this species does not belong to the Buccinoidea, but rather has strong affinities to the Conoidea, particularly the family Conidae (sensu Taylor et al. 1993). Comparison of the holotype of S. gaini with the holotype and paratypes of Belaturricula antarctica Dell, 1990,revealedthese two taxa to be conspecific. The following re-description of Belaturricula gaini uses the anatomical terminology of Taylor et al. (1993), as well as their classificationof the Conoidea.Throughoutthe text, "specimen" refers to a shell with preserved animal; "shell" refers to an empty shell.

Systematics
Family Conidae Fleming, 1822 Subfamily Clathurellinae H. & A. Adams, 1858 Beluturricula Powell, 1951 Powell, 1951:170; Powell, 1966: 34, pl. 3, fig. 5; Dell. 1991: 227-228. Type species designation.
-

Bella turrita Strebel, 1908, by original

Beluturricula gaini (Lamy, 1910) Srphogaini Lamy, 1910: 319, Lamy, 1911: 7, pl. 1. figs 7-8. Prosipho? guini - Thiele, 1912: 262. ?Chlanrdotu garnr - Powell, 1951: 142. Chlanidotagainr - Carcelles, 1953: 191, Dell, 1990: 177: Harasewych & Kantor, 1999: 293. Belaturricula untarcticu Dell, 1990: 228-229, figs 401. 43 1. Type locality: [Sipho gaini] Off King George Island, Sordh Shetlands, in 420 m; [Belaturricula antarctica] RV IIwo Sta. 465, off South ShetlandIslands, 62"56.9`S, 6Oo50.1'W. in 154 m. Type muterral; [Siphogaini] Holotype (Fig. la4, h), Museum national d'Histoire naturelle, Paris (M"), length = shell 32.9 mm; [Belaturriculr antarctica] Holotype (Fig. le-g), National Museum ofNatura1History, SinithsonianInstitution, USNM 860141, shell length=67.6 mm,frointhetypelocality;

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TAXONOMY OF SlPHO GAlNl

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Fig. 1. Beluturrzcula gaznr (Lamy, 1910) a-d. Holotype of Szpho gum Lamy, 1910 (d. operculum) Scale bar =1 cm h. Holotype of Stpho guznz at the same scale as other specimens In figure e-g. Holotype of Beluturrzcula unturctzca Dell, 1990, USNM 860141, i-j. USNM 901688, k-1. USNM 901689 (anatomy examined) Scale bar = 1 cm

paratype 1, USNM 860142, RV Eltanin, Sta. 437, Bransfield Strait, 62"50'S, 6Oo40'W, in 267-311 m; paratypes 2-3, USNM 860143,paratype 4, National Museumofnew Zealand MF. 56619,RVEltanin, Sta. 1003,Bransfield Strait, 62'415, 54"43'W, in 210-220 m; paratype 5, USNM 860144, RV Eltanin, Sta. 1079. E of South Orkney Islands, 61'26'S, 41'55'W, in 593-598 m.

55'25'W, 281-302 m, 1 specimen, USNM 901690. Bransfield Strait, 63'23.275, 57'00.41'W, 276-280 m, 1 specimen, USNM 897602; Low Island, South Shetlands, 63'18.51'S, 6I053.03'W, 228-264 m, 3 specimens, USNM 897631.

Material examined: Holotype of Sipho gaini, holotype and paratypes 1-3, 5 of Belaturricula antarctica, RV Eltanin: Sta. 410, offElephantIsland, South ShetlandIslands,61'18'S, 56"09'W, in 220-240 m, 2 specimens, USNM 881894; Sta. 1002, Palmer Peninsula, Joinville Island, 62'40'S, 54'45'W, in 265 m, 1 specimen, USNM 881974; Sta. 1079, Scotia hdge, 61'26'S, 41'55'W, in 593-598 in, 1 specimen, USNM 881986; Sta. 1885, S of Coulman Island, Victoria Land, Antarctica, 74'30'S, 170'10'E, in 3 11-328 rn, 1 specimen, USNM 870946; Sta. 1995, E of Cape Hallett, Moubray Bay, Victoria Land, Antarctica, 72'03'-72'04'S, 172'38'-172'06'E, in 344-348 m, 1 shell fragment, USNM 898007. RV Polarstern: Sta. 421008, off Elephant Island, SouthShetlandIslands,61'16'S, 55'50'W, 142-158 rn, 1 specimen,USNM 901688; Sta. 421028, E ofElephantIsland, South Shetland Islands, 60'59'S, 55'55'W, 214-219 m, 1 specimen, USNM 901689 (anatomy examined); Sta. 421 034, N of Elephant Island, South Shetland Islands, 60'535,

Description. Shell large (>90 nun, based on broken specimen measuring 83 mm. lacking lower part of columella and aperture), tlun, fragile, narrow, hsiform, with tall spire. Protoconch large (2.4-2.8 mm &lameter), rounded, of about 1% whorls, usually eroded. Teleoconch of up to 7.5 evenly rounded whorls. Suture tightly adpressed. Spiral sculptureof prominent spiral cords (55-82 on body whorl, 15-28 on penultimate whorl) of irregular width, as wide to much wider than intervening spaces. Axial sculpture of very fine axial striae, some raised to form inconspicuousaxial folds. Posterior sinus very shallow, subsutural, nearly indistinct. Aperture narrow, ovate, deflected from shell axis by 14-18". Outer lip very thin, fragile, evenly rounded, simple. Columella slightly less than half of aperture length, convex, with strong siphonal fold. Callus consisting of thn glaze overlyingparietal region and siphonal fasciole. Siphonal canal broad, short, straight. Shell color grayish toyellowish white inside and out, aperture thinly glazed. Periostracum yellowish, very thin, smooth, stronglyadherent, Operculumverysmall (<'A aperturelength), unguiculate, its nucleus strongly deflected posteriorly.


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One well-preserved specimen(USNM 90 1689, shell length 50.7 mm, Fig. Ik-1) was dissected and its anterior foregut embedded in paraffin and serially sectioned (10 pm sections, stained with Masson's trichrome). Epithelium of entire rhynchodeal cavity wall formed of tall, glandular cells, indicating that the rhynchodealwall does not take part in proboscisprotraction. Retrdctedproboscis(Fig. 2) ofmoderatelength,broad, withverytlunwalls. Mouth narrow in relaxed animals, capable of great expansion. Muscles of proboscis walls uniformly developed along its entire length. Buccal tube wide, with thin, folded walls lined with tall, columnar non-ciliated epithelium (Fig. 3 g, ep), lacks sphincters, andformsanintrovert (valvule) (Fig. 2, v; Fig. 3g) near the anterior third of the proboscis. Buccal cavity lined with tall epithelium (Fig. 2 bc). Buccal mass with thick, muscular walls and narrow lumen, partially projects from the rear ofthe retracted proboscis, spanning about % of proboscis length. Buccal lips absent. Circumoesophagealnerve ring (Fig. 2, con) at rear of proboscis. Salivary glands (Fig. 2, sg; Fig. 3f, sg) acinous, medium-sized,paired, not fused. Venom glanduniform throughout its length. Muscularbulb elongateoval, its wall formed of two layers of longitudinal muscle of equal thickness separated by a layer of connective tissue. Lumen of bulb lined with tall epithelium. Radula (Fig. 3) of long, slender, hypodermicmarginal teeth with smallbases and two distinct, medium-sized apical barbs. Tooth length about 810 pm (0.016 x shell length). A well-developed ligament (Fig. 3a)maintainsregulartoothmangementwithlntheradular sac.
=

Islands, as well as off the eastern margin of the Ross Sea, at depths ranging from 142 to 598 m. Ths species appears limited to bathyal depths along the Antarctic continent bordering the southernPacifcOcean,and the southernmargms of the Scotia Plate. Dell (1990: 229) conjectured that Belaturricula antarctica may prove to have acircum-Antarctic distribution, and tentatively identified a single, narrower, more stronglyribbed shell from the South SandwichIslands as this species. We have examined this worn shell (USNM 870759) and regard it to represent a Merent, possibly undescribed species of Belaturricula.
Remarks: Direct comparison of the holotype of "Sipho "gaini (Fig. la-d, h) with the holotype (Fig. le-g) and paratypes of Belaturricula antarctica coilfirms that these two taxa arc indistingushable in shell morphology, radular morphologyor anatomical organization, and therefore conspecific. The holotype of Szphogaini is ajuvenile specimen, and conforms to all the characters used to diagnose B. antarctica (Dell, 1990:229) apartfromsize. Thecorrectbinomenforthstaxon is Belaturricula gaini (Lamy, 1910).

Discussion
The genusBelaturricula was proposed by Powell (195 1: 170) to include the single species Bela turrita Strebel, 1908, described from the Shag Rock Bank, west of South Georgia. Powell did not compare Belaturricula to other genera of Turridae, but mentioned that the type species was similar to Pleurotoma (Surcula) dissimilis Watson, 1886, from bathyal depthsoff thePhilippines. Later, Powell (1969:362)tentatively transferred P. dissimilis to Belaturricula. As P. dissimilis is

Distribution: (Fig. 4) Belaturricula gaini occurs off the Palmer Peninsula, off the South Shetland and South Orkney

Fig. 2. Semi-diagrammatic longitudinal section through the proboscis Salivary ducts and loops of the venom gland are not shown A radular tooth is shown below the proboscis tip at the same scale Abbreviations bc = buccal cavity, bm = buccal mass, con = circumoesophageal nerve ring, Ibt = lumen of the buccal tube, oe = oesophagus, pw = proboscis wall, rd = radular caecum, sg = salivary gland, tt = radular teeth, v = valvule, vg = venom gland


TAXONOMY OF SlPHO GAIN1

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Fig. 3.Radula ofBelaturrzcula gatnz (Lamy, 1910) (a-e) a. single marginal tooth, scale bar = 200 mm, b, c. tooth base in two slightly different orientations to show the basal opening, scale bar = 50 mm, d, e. tooth tip in two different orientations to show the apical opening and barbs, scale bar = 50 mm, f. section through the salivary gland, g. section through the valvule Scale bars = 200 mm Abbreviations ep = tall, columnar epithelium, Ibt = lumen of the buccal tube, sd = salivary duct, sg = salivary gland

presently known only from the dead-collected holotype, a reassessment of the relationshps of this speciesmust await the availability of anatomical material. In treating the genus Belaturricula, Dell (1990) subdivided the type speciesinto two geographically separated subspecies, Belaturriculaturrita turrita (Strebel, 1908),endemicto South Georgia, and B. turrita multispirata Dell, 1990, from the Antarctic Peninsula and the South Shetland Islands. In the same work, Dell (1990) described a second species, Belaturricula antarctica (a junior synonym of Belaturricula gaini), which he regarded to have a broader, circum-Antarctic distribution. Examination of the substantialholdmgs of Belaturricula at USNM confirms that the subspecies B. turrita turrita is restricted in its distribution to South Georgia and the neighbouring Shag Rock Bank. It resemblesB. gaini, which does not occur off South Georgia, but differs in having finer

surface sculpture (>30 cords on penultimate whorl). The subspeciesB. turrita multispirata Dell, 1990,is characterized by an even finer spiral sculpture (5 1-63 cords on penultimate whorl). It overlaps geographically with B. gaini, but not bathymetrically. Belaturricula turrita multispirata has been reported from shallower depths (73-101 m) than B. gaini (154-598 m). When describing the genus Belaturricula, Powell (195 1: 166) did not assign it to any of the subfamilies of Turridae. Later (Powell 1969:362), he treated the genus as a member of the subfbly Turriculinae. At that time, Belaturricula included species known only from dead-collected material, so neither radulae, nor opercula were known. Dell (1990: 227) was the first to observe the opercula and radulae of B. turrita and B. gaini (as B. antarctica), and provided schematicdrawings of the radular teeth ofboth species (Dell 1990:figs 430,43 1). Because the radula is composed of hollow marginal teeth, the


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50

5 n

E.

10

d

20

30

40

50

60

0 12345 67 No. of spec.

Fig. 4. Geographic and bathymetric distribution of Belaturricula gazni (Lamy, 19 10) star = type locality, open square = type locality of B antarctica (Dell, 1990), circles = examined material

genus belongs to the family Conidae (sensu Taylor et al. 1993). In his list of generic names of conoideans, Sysoev (in Taylor et al. 1993) transferred Belaturricula to the subfamily Mangeliinae of Conidae. The subfamily Mangeliinae is characterizedbya small shell (usually 5-12 mm, but reaching 20 mm), the lack of an operculum, and by salivaryglands that are tubular. Our study ofB. gaini revealed this speciesto have a large shell (up to 90 mm), a large, distinctiveoperculum,and acinous salivary glands. The long, slender, narrow-based, radular teeth of B. gaini are most similar to those of species included in the highly variable subfamily Clathurellinae (e.g. Taylor et al. 1993, fig. 20 c, Schimek & Kohn 1981, fig. 12). The teeth of B. gaini are relatively long (about 1.6% of shell length) and comparable in size to those Clathurellinae. Other charactersthat uniteBelaturricula with Clathurellinaeare the lack of buccal lips as well as a rhynchodeal introvert. The buccal tubeintrovert (valvule) (Fig. 2, v) ofB. gaini is the first record of this structure in the subfamily Clathurellinae. Since B.gaini lacks buccal tube sphincters, this introvert is likely used to grasp and hold the radular tooth at the proboscis tip while stabbingprey. The distance from the mouth opening to the introvert is roughly equal to the length of tooth [a single tooth is shown (Fig. 2) at the same scale as the proboscis]. In his description of Pontiothauma ergata Hedley (19 16) commented on the similarity of this species to Sipho gaini. Comparison of the radula of Belaturricula gaini (Fig. 3a) with that of P. ergata (Hain 1990, pl. 17, fig. 2, Numanami 1996, figs 159D-E) reveals the two to be nearly identical in overall morphology, especially in the shape of the tooth base and in the number and orientation ofbarbs near the tooth apex. The radula of P. ergata has little in common with the radulae ofP. mirabile Smith, 1895 (type species ofPontiothaunm) or

P. abyssicola Smith, 1895, which both have a typical daphnelline radula with a large tooth base and a single, small barb at the apex (Powell 1966: figs 165-166). We therefore reassign Hedley's species to the genus Belaturrlcula as Belaturricufa ergata (Hedley, 1916). Another species assigned to the genus Ponthiothaunza, P. hedleyi Dell (1990), resembles Pontiothauma ergata m shell morphology. This speciesis presently known only from dead-collected material, and neither its radula nor its operculum, which could resolve its generic assignment, are known.

Acknowledgements
We are grateful to Philippe Bouchet for the loan of the holotype of Svho gaini, and to Michael Vecchione for providing preserved material collected aboard the RV Polarstern. Thanks are due to Walt Brown and Sussann Bradon for their assistancewith scanningelectronmicroscopy, and to Dr Donn Tippett and the referees, Drs H. Wagele and P. Bouchet, for helpful comments on the manuscript. This research was supportedby a grant from theNSF-USAP United StatesAntarcticProgram[ContractNo. OPP-95097611.

References
CARCELLES,1953 Catalog0 de la Malacofauna antarctica Argentiria A. Anales del Mriseo Nahuel Hiiapr, 3, 150-250. DELL, R.K. 1990. Antarctic Mollusca Biilletrn of Ihe Royal Society of New Zealand, 27, 1-3 11. HAIN,S.G. 1990. Die beschalten benthischen Mollusken (Gastropotla und Bivalvia) des Weddeilmeeres, Antarktis. Berichre 111r PolarJorschting, 70, 1-1 81


TAXONOMY OF SlPHO GAIN1
HARASEWYCH, & KANTOR, 1999. Arevision of the Antarctic M.G. Y.I. genus Chlanidota (Gastropoda: Neogastropoda: Buccinulidae). Proceedings of the Biological Society of Washington, 112,253-302. C. HEDLEY, 1916. Mollusca. Aiistralian Antarctic Expedition 191 I1914 Scientific Reports. C - Zoology and Botany, 4(1), 1-80. LAMY, E. 1910. Mission dans l'htarctique dirigee par M. le Dr Charcot (1908-1910): CollectionsrecueilliesparM. leDrJ. Liouville: Gastropodes prosobranches et scaphopodes. Bulletin dii Museum d'hrstoire naturelle, 16, 3 18-324. LAMY,E. 191 1 Gastropodes Prosobranches, Scaphopode et Pelecypodes. Deiixieme Expedition Antarctiqiie FranFaise (19081910) Science Naturelles: documents scientifrqiies. 1-32. NUMANAMI, 1996. Taxonomic study on Antarctic gastropods, H. collected by Japanese Antarctic research expeditions. Memoirs of National Institute ofpolar Research, Series E, Biology andMedical Science, No. 39, 1-244.

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POWELL, W.B. 195 1. Antarctic and subAntarctic Mollusca: A. Pelecypoda and Gastropoda. Discovery Reports, 26, 47-196. POWELL, W.B. 1966. The molluscan families Speightiidae and A. Turridae. Bulletin of the Aiickland Institute and Miisetim, no 5, 1-184. POWELL, A.W.B. 1969. The family Turridae in the Indo-Pacific. Part. 2. The subfamily Turriculinae. Indo-Pacific Mollusca. 2, 2 15-415 SHIMEK, & KOHN, R.L. A.J. 1981. Functional morphology and evolution of the toxoglossan radula. Malacologia, 20, 423-438. TAYLOR, J.D., KANTOR Yw.1. & SYSOEV A.V. 1993. Foregut anatomy, feeding mechanisms, relationships and classification of Conoidea (=Toxoglossa) (Gastropoda). Btilletin ofthe NaturalHistoryMuseiim, London (Zoology), 59, 125-169. THIELE, 19 12. Die antarktischen Schnecken und Muscheln Deiitsche J. Siidpolar-Expedition 1901-1903. 13, 183-285.