THE NAUTILUS 123(3):137-147, 2009 Page 137 Unusual anatomy of the ectoparasitic muricid Vitularia salehrosa (King and Broderip, 1832) (Neogastropoda: Muricidae) from the Pacifie coast of Panama Luiz Ricardo L. Simone Gregory S. Ilerberl Didier Merle MiiseucleZoologiadaUniversidadede SaoPaulo Departiiieut of Ceolog\- Departemeut lli.stoire de laTerre (CP3S) C.R 42494 Uuiversit)'of Soutli Florida UMR 5143 & LISM 203 04299-970SaoPaulo, BRAZIL 4202 Ea.st Fowler Aveuue Paleobiodiveisite et Paleoemironnements [email protected] Tampa, FL33620 USA Mu.seum National d Ili.stoire Naturelle [email protected] S, me Buffon F-75005 Pails, FRANCE [email protected] ABSTRACT ute to asystematic re\ision ofthe genus Vitularia Swain- son, 1840 (t\qrespecies: Vitularia miliaiis (Gmelin, 1791)). The morpholog)'and anatomyof Vitulariasalehrosa. a muricid ectoparasitic on other inollusks, are investigated based on study ofspecimens from western Panama. Distinctive charac- MATERIALS AND AIETHODS ters of this species include tlie small size of the buccal mass and radular apparatus, simplification ofthe odontophore mus- Specimens were obseiwed li\ing, followed by dissections cles and diminished lateral teeth of the radula; an elongated, performed on specimens immersed in 70% ethanol and narrow proboscis; narrow digestive tract and a differentiable obser\'’edusingastereomicroscope. Scanningelectron mi- glandular region at the beginning of the posterior esophagus. These traits are consistent with adaptive specialization for an croscopy (SEM) was used to examine the radnlae in the ectoparasitic life histoiy. laboratoiy of Electron Microscopyof the Museu de Zool- ogia da Universidade de Sao Paulo. Drawngs were made with the aid of a camera Incida, and dissections w^ere also digitally photographed. The conchological description uses the terminokyg\' of Aleiie (2001, 2005). Acronyms for collections cited in this paper are MZSP, Museu de Zoologiada Universidade de Siio Paulo, and PRI. Paleon- INTRODUCTION tological Research Institution, Ithaca, New'York, USA. Herbert et al. (2009) liave shown that Vitularia salehrosa (King and Broderip, 1S32) is an ectoparasitic gastropod RESULTS that can feed snctorially on a single rnollnscan liost for months by drilling through the host’s hell and inserting DESCRIPTION its proboscis into the host’s blood supplies and oi'gans. One of the questions raised in that study was whether Vitularia salehrosa (King and Broderip, 1832) and to what degree the anatomy of V. salehrosa has (Figures 1-33) undergone adaptive specialization lor an ectoparasitic Murex salehrosus King and Broderip, 1832: 347. lifestyle. For example, foot scars formed by U salehrosa Vitularia salehrosa: Keen, 1971: 536 (fig. 1040); Radwin on the surface ofits host’s shell suggest that this ectopar- and D’Attilio, 1976: 173-174 (figs. 04, 115; pi. 7, fig. asite produces mucous adhesives in its foot to help it 14); Ramirezetal,2003: 261; Paredes etal., 2004: 214. attach itself securely to prey during feeding (Herbert et ah, 2009). D’Attilio (1991) and Herbert et al. (2008) Shell (Figures 1-3, 6-8): Shell surface pustulose. also reported the absence of a radula in 80-90% of Protoconch multispiral, with numerous granules, aligned U salehrosa individuals examined. Radnla loss is charac- in a.xial and spiral directions. Sinusigeral scar well teristic of the muricid subfamily Coralliophilinae, which marked. Early teleoconch w'horl with PI cord. Axial are highly specialized ectoparasites ofcnidarians. sculpture w4th lamellose vaiices. Adult teleoconch with The objective of this study is to describe for the first onlyPI evident. Infrasutura! denticle split, eight internal time the anatomy ofVitularia salehrosa to serv'e as basis denticles present, perhaps corresponding to D1 to D6 for furthercomparisonswith other mmicids andcontrib- or D1 to D5 (w'ith several .split denticles). Columellar Page 13S THE NAUTILUS, Vol. 123, No. 3 L. R. L. Simone et ;il., 2()09 Page 139 tubercles absent. Microstructure wdtli tliree shell layers; of mantle cavity length, about 1/2 its w'idth. Anterior an innermost, thin aragonite layer, a thick, middle arago- end ofctenidinm pointed, inserted into right surface of nite layer, and one thin, outer calcite layer (Figure 13). tall fold formed by right siphonal base. Ctenidinm Complementaiy descriptions in Radwin and D'Attilio uniform in widtli along most of its length, increasing in (1976: 173-174) and Herbert et al. (2009). size relatively abruptly toward the posterior margin. Posterioi' end of ctenidinm rounded, situated close to Head-Foot (Figures 14, 15, 20): Head not protrud- posterior end of mantle caxht)' and to pei'icardium. Cte- ed, small (about 1/4 ofadjacent width ofhead-foot). Ten- nidial filaments triangular, spanniug ~l/2 mantle cavit)' tacles stubby, lu'oad, flat,broaderbasally; length about 1/3 lieight, apex central, slightly turned to right, lelt and ofwader width of head-foot. Eyes dark, small, situated in right edges straight. Afferent ctenidial vessel veiy nar- middle region of outer edge of tentacles. Tentacles row, running along right margin of gill. Space between situated close to each odier, with space between them ctenidinm and right pallial organs roughly 1/2 gill \\4dth. about 1/2 the tentacular wadth. Rhynchostome a small, H\pobranchial gland thin, wdth uniform surface, pale- transverse sht locatedbetw^een and slightlyventnrl toten- Ireige, covering most of area between the gill and right tacles. Foot large, spanning about 1/2wdiorl. Anterior fur- pallial structures. Right side of mantle cavity nearly rowofpedalglands exendingalongentire anterioredgeof filled by gonodncts (Figures 16, 32). Rectum veiy nar- foot. Columellar muscle thick, about 3/4 wdiorl in length. row, almost filiform, running along right edge of mantle Haemocoel long, slightlybroader anteriorlyand narrower ca\4ty in young specimens, dislocated to left by gono- posteriorly (Figure 20). Accessoiy boring organ (ABO) dncts ofmature specimens. Anns veiy small, situated at veiy narrow' and relatively deep (about 1/4 of foot thick- 1/4 mantle caxity length from mantle edge, with small ness), better developed and associatedw4th cement gland terminal papilla (Figures 16, 32, ap). in females (Figure 15, fc); sharingthe same aperture. Visceral Mass (Figures 26, 29): Visceral mass taper- Operculum (Figures 4, 5): Suboval, filling entire ap- ing, spanning ^2V2w'horls posterior to the mantle cavity'. erture. Superior edge rounded; inferior edge broadly Digestive gland pale-beige w4th small black spots, occn- pointed; inner edge almost straight in inferior half and p)4ng most of the visceral mass, surrounding the stom- rounded in superior half; outeredge uniformly rounded. ach, extendingfrom visceral apexto kidney-pericardimn. Outer surface opacpie, mostly smooth; conspicuous Gonad also pale-beige, situated along the columellar scales parallel to edge in superior and inferior slopes of surface of the digestive gland, extending from the first outer edge. Nucleus at middle level of outer margin. w'horl to 1/2 w'horl posterior to stomach. Attachment scar occupying about 80% ofinner surface, w4th concentric, somewhat uniform undulations. Outer Cii'culatoiyandExcretoiySystems(Figui’e 17): Reno- margin glossy, uniform in width (about 1/4 opercular pericardial region spanning ~l/3 w'horl, situated at an- width) alongentire length ofoperculum. terior margin of \4sceral mass, partly adjacent to the mantlecavity, roughlytriangularin cross-section, lu'oadest Mantle Cavity Organs (Figures 16, IS): Mantle along right margin. Pericardium occup)4ng ^1/3 of reno- ca\4ty spans about one w'horl. Mantle border simple, pericardial region, just posterior to gill at anterior-left slightly thickened. Siphon comprises about 1/3 of free margin of\4sceral mass (Figures 16, 29), Auricle anterior portion of mantle edge wudth and about 1/3 wdiorl in to ventricle, connected to ctenidial vein (efferent bran- length. Right edge ofsiphon base forming tall fold that chial vessel) at its left-anterior side, to reno-pericardial runs parallel to mantle edge and e.xtends approximately duct along its right side; distance between connections 1/2width ofmantle ca\4ty (Figure 16, se); middle region ~l/4 adjacentwTorlwidth. Ventriclespheiical, connected ofthis fold tall (about 1/2 ofmantle ca\4t)' height), right to aortas at its posterior-left side. Af>rtas narrow, anterior end ofthis fold diminishing gradually, becomingw'eaker aorta about twice diameter of posterior aorta, running near mantle edge. Osphradium elliptical, 1/4 mantle parallel to esophagus. Kidney somewiiat elliptical in cavity length, 1/5 of mantle ca\4ty roof width. Osphra- outline. Renal lobe single, mostly solid, with imbricated, dium leaflets very low (about 1/4 width); tips sharply septnm-like, transverse, glandular folds, all connected pointed, turned e.xternally. Anterior portion of osphra- at middle region of ventral surface by longitudinal dium well-separated from gill. Osphradial neive enters efferent renal vessel coming from haemocoel; lobe sur- in middle region ofosphradial ganglion (Figure 16, on). rounding intestine-rectum transition alongside right re- Ctenidial vein (efferent branchial vessel) uniformly nar- gion; color cream, surface transversally folded, filling row, along its length. Ctenidial longitudinal muscle cov- most of kidney inner space, not connected to ventral ers about 3/4 of ventral surface of ctenidial vein renal surface. Nephridial gland ~l/4 width of renal lobe, (Figure 18, gm). Ctenidium elongated, spanning 85% triangular in secbon; covering entire membrane between Figures 1-13. Vittikiria salchrosa. shells. 1-3. PRI 9468, apertiiral, dorsal and profile views, length = 40.0 inni. 4-5. T\pical opercnlinn, outer and innerviews, scale bar = 2 nun. 6-8. SEM of Protoconcli, PRI 9469. 6. Lateral-sliglitly apical \iew'. 7. Lateral view. 8. Detail of sculpture ofpenultimate wiioii, scale bar = 50 pm. 9-12. Radulae of 3 specimens, SEM. Scale bars = 20 pm. 13. Transverse section ofshell. SEM, scale = 100 pm. Page 140 THE NAUTILUS, Vol. 123, No. 3 L. R. L, Simone et al„ 2009 Page 141 kidney and pericardium, vender dorsally. Nephrostome ol their length; mil, paired ventral tensor muscles of a small slit in kidney wall in mantle cawt)' (Fig- radula, thin, narrow, originating at median-posterior ures 16, 17, ne). ends of odontophore caitilages, extending dorsally to m5 origins, running anteriorly at some distance from Digestive System (Figures 19-26): Proboscis nar- median line, inserting along anterior surface of ventral row and very long (~3 times shell length, 1/4 haemo- region of snbradular membrane (Figure 24). Other coel width), outer walls thin, muscular (Figures 20, 21). uou-muscular odontophore structures: hr, subradular Pairs of ventral proboscis retractor muscles (rm) nar- membrane, tliin, semi-transparent, strong, connecting row, originating in dorsal surface of foot, concentrated to m4 muscle pair at lateral and antei'ior edges, cover- along right region, just ventral to head (Figure 20); ing inner surface of subradular cartilage; sc, subradular closer to buccal mass, retractor muscles almost imper- cartilage expansions, elliptical, covering about halt of ceptible, embedded in proboscis wall (Figure 21). exposed portion of subradular memlirane within buccal Mouth transverse, narrow. Oral tube short, broad, walls ca\4ty, bearing exposed part of radula, expanding be- weakly muscular. Dorsal folds paired, originate along yond it laterally equal to tlie width of the radula on dorsal, inner surface of oral tube, become more longi- each side; oc, odontophore cartilages, Hat, long, paired, tudinal posteriorly (Figure 23, clf), \Mth a narrow, about 5 times as long as wide, elliptical in outline, smooth surface between them. Odontophore veiy anterior somewhat pointed, sliglitly wider than rounded small, ~1/15 proboscis volume, situated jrist posterior posterior; to, tissue on radula posterior to its exposed to mouth (Figure 21, od). Odontophore and buccal portion within buccal ca\4ty, located inside radnlar sac mass muscles (Figures 23-25): inj, peribuccal muscles, along its I'egion crossing odontopliore, m4 muscle pair paired, thick layers of muscles connected along both insert into it laterally along a region ~f/10 cartilage sides of anterior-outer margin of odontophore carti- length. Radnlar sac narrow (~l/5 of odontophore lages (Figures 24, 25), embedded in dorsal wall of \\4dth), long (4 times buccal mass length) (Figure 19). buccal mass; ml, jugal muscles, several pairs of small, Radnlar nucleus (odontoblast region of radnlar sac) short fibers connecting buccal mass \\4th adjacent inner slightly liroad, connected to inner surface of proboscis surface of proboscis; m2, pair of retractor muscles of by relatively wide vessel with thin, muscular walls (Fig- buccal mass (retractor of phaiynx), originating in ven- ure 19). Radnlar teeth (Figures 9-12): Rachidian teeth tral surface of haemocoel (dorsal surface of foot sole) wide, ~3/5 of radnlar ribbon wdth, clievron-like, \\4th at mid-length, just posterior to proboscis retractor mus- 7 conical, pointed, posteriorly-dii'ected cusps that are cles, extend anteriorly and dorsally as a pair of incon- not aligned; central cusp taller, at a greater angle to spicuous longitudinal muscles, inserting into posterior ribbon than remaining, lateral cusps, which are situated end of both odontophore cartilages; m4, pair of large, nearly on the same plane; lateral edges of rachidian broad, thin, dorsal tensor muscles ofradula, originating teeth broad, llattened. Lateral teeth paired, veiy nar- along outer surface of cartilages, suri'ounding mj ori- row, ~1/(S of rachidian teeth width, equal to rachidian gin, covering most of cartilage surface (except edge teeth in height (L/VV ~5), weakly cmved; bases wider, close to median line), inserting mostly into subradular inserted into subradular cartilage close to proximal membrane, and also in a small region of tissue in radii- region of rachidian teeth lateral edge; tip shaiyly point- lar ribbon (anterior to its e.xposed area) (Figures 24, ed, turned posteriorly. Salivaiy glands just posterior 25, to); m5, pair of auxiliaiy dorsal tensor muscles of to valve of Leililein, anterior to neive ring (Figure 21, radula, thin, originating along median edges of carti- sg), occupying ~1/S of haemocoel volume. Salivaiy lages along their posterior, quarter, running medially gland ducts veiy narrow; gradually become embed- and anteriorly, inserting along ventral portion of radu- ded iu anterior esophagus wall anterior to valve of lar sac, crossing odontophore (opposite to m4 inser- Leililein (Figure 21). Accessoiy salivaiy glands absent. tions in tissues on radula); m6, horizontal muscle, Anterior esophagus narrow, long (Figure 21), eijual in relatively thin, connecting ventral edges of both carti- length to proboscis, inner surface smooth, with pair lages, from anterior end ofcartilages, posteriorly ~60% of low, narrow longitudinal folds in anterior region Figures 14-19. Vitularia salebrosa anatomy. 14. Head-foot, male, frontal riew. 15. Foot, female, longitudinal section in median line. 16. Mantle cavity roof, female, ventral view, transversal section in fold of right base of siphon artificially ilone. 17. Reno- pericardial region, venti'al view, ventral wall of pericardium and part of kidney removed, posterior region of renal lobe partially deflected. 18. Mantle cavity roof, female, transversal section in middle level of osphradium. 19. Distal region of foregut, ventral- right view, distal portion ofproboscis also showai. Scale bars = 2 mm. Abbreviations: aa, anterior aorta; ae, anterior esophagus; af, afferent branchial vessel; an, anus; ap, anal papilla; au, auricle; be, bursa copulatrix; bv, blood vessel; cm, columellar muscle; cv, ctenidialvein; ey, eye; fc, femalecementglandpins boringorgan; fp, female pore; fs, footsole; ft, foot; gi, gill; gin,gill longitudinal muscle; he, haemocoel; hg, hypobranchial gland; kcl, kidney dorsal lobe; ki, kidney chamber; kin, membrane between kidney and mantle cavity; m2, buccal mass and odontophore muscles; mb, mantle border; mo, month; ng, nephridial gland; ne, nephrostome; oa, opercular pad; od, odontophore; og, osphradium ganglion; on, osphradium nerve; op, operculum; os, osphradium; ot, oral tube; ov, pallial oviduct; pa, posterior aorta; pb, proboscis; pc, pericardium; pg, pedal gland furrow; pp, penis apical papilla; rs, radnlarsac; rt, rectum; i*v, efferent renal vessel; sd, salivaryduct; se, fold ofsiphonal base; si, siphon; te, cephalic tentacle: vd, vas deferens; ve, ventricle; vs, bloodvessel. Page 142 THE NAUTILUS, Vol. 123, No. 3 L. R. L. Simone et ul., 2009 Wigc 143 (Figure 23, tlf). Valve ol Leihlein slightly wider than rowing abruptly, rounded; apical papilla narrow, ~f/S of surrounding esophagus, anterior half conical, posterior penis lengtli, located within protective apical chamber halfrounded (Figure 22). Internally, valve anterior with that occupies ~l/l() ol penis volume (Figure 27). Penis a tall cylindrical fold, with relatixely short cilia directed duct (~l/6 of penis width) runs alongpenis axis, strongly posteriorly (Figure 22). Remaining portions ol valve ot coiled at mid-length (Figure 27), narrowing at papilla Leiblein entirely covered by inner, thick whitish glan- base, opening at papilla tip. dular layei'. Mitldle esophagus about same diameter as anterior esophagus (Figure 21); inner surface smooth, Female Genital System (Figures 16, 32, 33): Visceral simple. Gland ol Leiblein occupying ~l/3 ol liaeino- oviduct relatively wide, entering left posterioi' region coel volume, broad, Hat anteriorly, gradually nai'rowing ol albumen gland (Figui'e 32). Pallial oviduct massive posteriorly, becoming vei'v narrow, sharply pointed (Figure 16), (~2/3 lengtli, ~l/3 width of mantle cavitv). (Figures 20, 21). Duct of gland of Leiblein broad, Albumen gland .spherical, llattened, walls tliick, white, situated at some distance from anterior end of gland. about ~l/4 pallial oviduct length; lumen broad and Hat, Posterior esophagus narrow, etjual in length to anterior continnous with that of capsule gland. Gapsule gland esophagus (Figures 21, 26), with a broadly expanded long (^2/3pallial oviduct length), slightly narrowerthan, glandular region (Figures 21, 22, eg) situated beneatli ami anterior to, albumen gland; walls thick, glandnlar, gland of Leiblein, posterior to duct of gland of Leiblein pale beige in color; lumen broad and flat (Figure 32). (by ~1/10 posterior esophagus length). Glandular lin- Anterior region of capsule gland with thinner walls, ing of this region of posterior esophagus about twace formingvaginal atrium (Figures 32, 33, vg). Bursa copii- as thick as escipbageal wall. Stomach a simple cun’e latrix elliptical, ~f/6 pallial oxiduct length, situated on (Figure 26), e(|ual in width to esophagus, located about ventral, left side ol anterior end ol pallial oviduct. Rursa 1/3 whorl posterior to kidney, embedded in digestive walls thick, longitudinally folded. Gapsule gland and gland. Inner surface smooth, simple. Duct to digestive bursa copulatrix ducts converge anteriorly to form small gland single, joining stomach in posterior gastilc cune, genital papilla (Figure 33, fp), located wltliin small chamber. about equal in diameter to intestine. Intestine as wade as esophagus, nearly straight, running anteriorly along Central Neiwous System (Figures 20, 21, 30, right region of visceral mass, passing tlirongh ventral 31): Neiwe ring located in anterior region ol liaemo- region of renal lobe (Figure 17). Digestive gland, rec- coel, at proboscis base (Figures 20, 21). Nen'e ring tum and anus described above. x’olume approximately 1/20 that ol baemocoel. Ganglia liighly concentrated and difficult to separate. Gerebral Male Genital System (Figures 14, 27-29, 36): Vis- and pleural ganglia paired, totally fused. Pedal ganglia ceral vas deferens running b'om testis along columellar paired, as large as cerebro-pleural ganglia, broadly surface of\4sceral mass to intensely coiled seminal \'esi- connected to each other and to remaining main ganglia. cle located on mid-ventral region of lastwhorl of visceral Sub-esopliageal gaugliou close to nei've ring, about hall mass, comprising ~l/4 of mass of adjacent region ol the size of a pedal ganglion. Statocysts not found. visceral mass (Figure 29, sv). Vas deferens nari'ow, sim- ple, straight, runningalongventralwall ofkidney, e.xitiug Measurements (in mm): MZSP 63824: $1: 64.7 by into mantle cavitv along.its middle-posterior edge (Fig- 33.1; J3: 47.4 by 25.8; MZSP 64213 91: 62.1 bv 28.4; ure 29, vcl). Pallial vas deferens strongly comohited for PRl 9468: 40.0 by 22.3 (Figs. 1-3). 1/4 of mantle cavit)' length along right-ventral edge of mantle cavitv', connecting to posterior end of prostate Geographic Distribution: Baja California to Peru. gland. Prostate gland ~l/4 of mantle cavitv length, ~1/1() its width (Figure 2S, pt), with glandnlar, irides- Habitat: Under rocks, intertidal and subtidal. cent, walls narrowing anteriorly, lacking clear separation with remaining anterior vas deferens, which crosses to Material Examined: W. PANAMA (Gulf Panama): pallial floor at level of anus, winding sigmoidally to base Panam;i CiG, MZSP 10173, 1 shell; Gbumical Arerajan, of penis (Figures 14, 27, 36); pallial vas deferens entirely Ghumical Bay Playa, 08°53'08.8" N, 79°38'37.7"' W, closed (tubular) (Figure 27, vd). Penis broadest medially MZSP 63824, IJ, 2$ (Simone col., 29 fan. 2006); (1/3 penis length), somewhat llattened, occupies ~l/6 Venado Island, 08°52'48.6" N, 79°35f36.9"‘ M', MZSP mantle cavitv volume, cui'ved at base; apical region nar- 64213, 4J, 29 (Simone col. 30 Jan. 2006), MZSP 77671, Figures 20-22. Vitiihnia s(del>rosa anatomy. 20. Head and haeniocoel, ventral xiew, loot and coinniellar innscle removed, inner structures as in situ. 21. Foregnt removed, ventral view, some adjacent structures also shown. 22. Detail ol h)regnt region betwc-en \alve andglandof Leiblein, ventral view, with detail ol valve opened longitudinally, a tran.sversal section artiliciallydone in proximal region of posterior esopliagns. Scale bars = 2 mm. Ahhrex’iations: aa, anterior aorta; ae, anterior esophagus; di, diaphragm-likc‘ septum; ea, anterioresophagus; eg,gland otposterioresophagus; eni, middleesopliagtis; ep, posterioresophagus; ey, eye; ge, suh- esophageal ganglion; gl, gland f)l Li'ihleiii; gp, pedal ganglion; Id, duct of gland of Leihlein; ino, mouth; od, odontophore; pb, proboscis; pg, pedal gland tmrow; rni, proboscis retractor muscle; r.s, radnlar sac; i"vv, rlnncliodeal wall; ly, ihvncliostome; sd, salivarx'duct; .sg, salivaiygland; te, cephalic tentacle; tg, integument; vl, x'alx'e ot Leihlein. Page 144 THE NAUTILUS, Vol. 123, No. 3 23 sa vd tg L. R. L, Simone et al., 2009 Pa>^e 145 3$, 83792, 7 specimens (Simone col. 01/ii/200fi), 1M\I dorso-\’entrally, wath a clearer separation between the 9468, 2 specimens (Figures 1-3, 6-8). Las Perlas Arclii- pedal ganglia and the remaining ganglia). pelago, 08°2P27.7" N, 78°50'28.7" ^V, MZSP 78481, This study did not conlirm tlu' lindings ol D’Attilio 2 specimens (Simone col. 4 Feb. 2006). COSTA RICA: (1991) and Herbert et al. (2008), who reported (hat as )oce Beach, PRl 9469, 1 .specimen. ECUADOR: Man- many as 80-90% of animals studied lackc'd a radnia. .All ahi; Isla Salango, MZSP 67408, 1 shell, MZSP 69597, 12 animals dissected in this analysis (n=23) possessed a shells (Coltro col. Mar. 2003). radnia. The different results obtained herc'in can be interpreted several ways. Herbert et al. (2009) foinid DISCUSSION that ectoparasistic interactions between an indixidnal yUiildria salebrosa and a single molluscan host can last The anatomy of Vihilaiia salebrosa is comjiarabic to many montlis and possibly as long as a year. They also that described for rinmerons mnricids (e.g., Ilarase- lonnd that interactions witli new oystc'r prey appc'ar to \\Tch, 1984; Kool, 1987, 1993a, b; Ball et al„ 1997; start at tlie same time each year. Because U salebi'osa Tan and Signrdsson, 1996; Tan, 2003; Simone, 2007), re(juires a radula to initiate the intc-raction by drilling a and shares leatnres cliaracteristic of the lamily, among feeding hole, it may be tliat a innetioning radnia is them a mantle border that closely surrounds the si- present sporadically, and perhaps seasonally (soo also phon, an accessoiy boring organ, and an anal papilla. Herbert et al., 2009). An alternative explanation is that However, several aspects of the moiphologv' of V salc- the radula was destroyed b\ the cleaniug process used hrosa appear to be nnicjue. These incinde: (1) a tall, in past work, which imolved dissolving tissues either iu septnm-like Fold at the right base of the siphon (Fig- concentrated potassium hydroxide, or in a bleach-like ure 16, ,se); (2) an elongated proboscis (F’ignre 21) solution. It is not clear, howex'cr, why this techniqne (mnricids normally bear a well-developed, but shorter works so well for other mnricids but would fail consis- proboscis); (3) a small and simple buccal mass, particu- tently for U salebivsa, unless its ladula is sometimes larly the odontophore (Figure 19), with small iii6 and non-mineralized. It is also possible that the long pro- retractor muscle pairs iri5, and tlie lack of a mnsnilar boscis was accidentally amputated by collc'ctors \igor- connection in the radnlar sac (Figures 24, 25); (4) a onsly pulling the feeding animal Ironi its host. Eacfi ol relatively small pair of lateral teeth on the radnia (Fig- tliese explanations can be easily tested in Inture woik. ures 9-12); (5) a digestive .system that is simplilied and Differences in tlie digestive sy,stem betwec'ii Vilniaria reduced in diameter (Figures 21, 22, 26), particularly salebrosaandothermnricids,particularlythesimplification the stomach, which is reduced to a simple, iucouspicu- andreductionindiameterol itsgnt,arecompatiblewith an ous cun'c that is joined by the duct of the digestive ectoparasitic mode ol life. On the other hand, as the diges- gland; (6) a reduced valve of Leiblein that lacks a tive.system iscompletein V.salebrosa, it ispossibletoinfer tran.sverse furrow, or by-pass, along its length (Fig- thatparasitism is notobligaton’, and that normal predatoiy ure 22, vl); (7) a mid-esophagus that is simple, rather beha\ior can also occni'. The muricid snblamily Coral- than glandular as in mo.st mnricids (Figures 21, 22, liophilinae is knowm to incinde .speck-s that are ectopara- eg); (8) an anal gland (Figure 32, ag) that is unusually sitic on cnidarians, yet there are lew' paralk'ls between elongated; (9) a prostate gland that is relati\'ely small, the anatomy of coralliopfiilines and that ol U salebrosa. with a long, convoluted vas deferens in the mantle Astrikingaspectoftheanatomyof V. salebrosa isthehighly cavit)' (Figure 28); (10) a penis with a terminal papilla rc'duced diameter ol its digestive tract, although it has (common in mnricids) that is protected by an unusual retained a hilly functional buccal mass and odontophore. terminal chamber. Similarly, the female genital pore is In contrast,coralliopfiilineshavesnileredsevereatrophyof also protected in a small, hollow chamber (Figure 33), theanteiiorportionol thedigestive.system,particnlaiiytlie wliile the remainder of the pallial oviduct is normal lor buccal mass, inchuling the total loss ol tlie odontophore, the family; and (11) a central nervous .system, or nerve ratliila, and related structures. Ilowever, the remaining ring, that is more concentrated than usual (Figure's 30, portions ol the digestive system in coralliophines are rela- 31) (normally, the muricid neiwe ring is slightly longer tivelysimilartothoseol otlier mnricids. Figures 23-28. Vifiihiriasalebrosa anatoniy. 2.3. Buccal mass, riglitview', esopliagiis andventral region openi'd longitudinally, w'ay ol riglit salivaiy duet partially sliowni, radnlar sac only paitially sliow'ii. 24. Odontophore, x'entral \ie\v. 215. Same, \(*ntral \ie\v, left .structures (right in Figure) partially dellected, snperlicial layer of tissues remo\-ed. 26. V'isceral partially uncoiled show'ing topology ol midgnt, v’entral view, topologv'of some portions of reno-jiericardial structures also show'ii. 27. Penis and adjacent rc'gion ol head, dorsal view', some penial innerstructures artiliciallyshow'ii. 28. Detail ol right region of mantle ca\itv, male, ventral \iew', with focus on genital structures, a tran.sverse section through middle region. Scale bars = 1 mm. Abhreiiations: aa, anterior aorta; ad, adrectal sinus; ag, anal gland; hr, suhradiilar membrane; dd, duct to digesti\e gland; df, dorsal inner folds of buccal mass; ea, anterior esophagus; ep, posterior esophagus; in, intestine: ir, insc'ition ol ni4 radnlar sac; ki, kidney chamber; nil-nill, buccal mass and odontophore muscles; mb, mantle border; inj, peri-oral musek's; mo, mouth; oc, odontophore cartilage; od, odontojihore; ot, oral tube; pc,pericardium; pd,penis duct; pe,penis; pi,prostategland; ra, radula; rs, mdularsac; rt, rectum; sa,salix'an duct apertuic; sc, subradular cartilage; sd, salivaiy duct; si, gastric region; Ig, integument; to, tissue connecting iu4 with radulai' sac; vd, \as deferens; vm, visceral mass; vp, ventral platform ol buccal mass. Page 146 THE NAUTILUS, Vol. 123, No. 3 structures also showai, atransversal section ofindicated region also revealed. 33. Detail of anterior region of pallial oviduct, ventral view, with inner terminal genital pajiilla protruded. Scale bars = 1 nun. Ahhre\iations: ab, allnnnen gland; ad, adrectal sinus; ag, anal gland; an, anns; ap, anal papilla; be, bursacopnlatrix; ee, cerebro-plenral ganglion; eg, capsule gland; da, anal gland duct; es, esophagus; fp, leinale pore; ge, snb-esopliageal ganglion; gp, pedal ganglion; ki,kidneychamber; rt, rectum; sv, seminalvesicle; ts. testis; vd, vas defereiis; vg, vaginal ati'iniu; vo, visceral ovirlnct. ACKNOWLEDGMENTS Ellen Strongfororganizingfieldworkduringthe Neoga.s- ddie authors tliaids the Smithsonian Tropical Research tropod Evolution Workshop in Panama in [aimaiy 2006. Institute marine lab at NAGS, and the government ol Emily Yokes and Geerat Vermeij kindly provided shells Panama lorcollection permits, and )c-ny Ilarasewych and figured in this .study from their research collections.