Biodiversity Journal, 2012, 3 (2): 123-128 A new species of Petaloconchus Lea, 1843 from the Mediterranean Sea (Mollusca, Gastropoda,Vermetidae) Danilo Scuderi Dipartimento di Biologia Animale, Laboratorio di Biologia Marina, Università di Catania, Via Androne, 81 - 95124 Catania, Italy; e-mail: danscu@tin.it ABSTRACT Petaloconchus (Macrophragma) laurae n. sp. is a vermetid here described as new. It is very similar in shell characters to both the species reported for the Mediterranean sea, the fossil Petaloconchus intortus (Lamarck, 1818) and the recent Petaloconchus (Macrophragma) glomeratus (Linnaeus, 1758), but the peculiar structure of the internal keels and the protoconch distinguish the new species from all the congeners; the external morphology of the soft parts add a new item in the discrimination of the recent species. The holotype of P. glomeratus is housed in BMNH and it is here compared with the new species. KEY WORDS Vermetidae, new species, Petaloconchus n. sp., taxonomy, Mediterranean Sea. Received 18.04.2012; accepted 19.06.2012; printed 30.06.2012 introdUCtion The species of the genus Petaloconchus Lea, 1843 are characterised by the presence in the columellar zone of a series of structures, i.e. internal keels, whose number and arrangement is a character for the first time described and utilised by Carpenter (1856) as a species-specific character. Petaloconchus is well represented in tropical waters by numerous species, but in the Mediterranean sea only one recent species is known, P. (Macrophragma) glomeratus (Linnaeus, 1758). The validity of this peculiar character, proper to Petaloconchus, and the development and morphology of the earlier tele-whorls in vermetids is here reported as a good species-specific discriminating character on the basis of the study on 10 of the 25 extant species of Petaloconchus and is discussed in conclusions. A second unknown Mediterranean species of Petaloconchus is here described as new: the morphology of shell, protoconch and external soft parts are described in detail and compared with the holotype of P. glomeratus and with P. intortus (Lamarck, 1818), a fossil congener of the plio-pleistocenic Mediterranean area. The new species is here distinguished by any other species of Petaloconchus mainly on the basis of the internal keel arrangement and the shape of protoconch: additional characters useful to distinguish the new species are here reported. The close related tropical species are here compared to the new species. MaterialS and MethodS Dry and living materials of both the new species of Petaloconchus and P. glomeratus were collected by undermining the shells from hard substrates at a depth of 0 to -18 m; empty shells were found among residuals of fishing nets at a depth of 50 to 150 m. Protoconchs of both species were collected by digging them with a needle from the base of specimens and by extracting them from the brooding females; further empty material was collected 124 DaniloScuDeri among the shell grit collected handily with ARA. Drawings of the external soft parts were obtained observing the living animals in aquarium. fossil materials of both P. glomeratus and P. intortus were studied and compared to the new species. ACRONyMS. Australian Museum, Sydney, New South Wales, Australia (AMS); Danilo Scuderi collection, Catania, Italy (DSC); Angelo Lugli collection, Carpi, Modena, Italy (ALC); Moscow State University, Moscow, Russia (ZMUM); Museo Civico di Zoologia, Roma, Italy (MCZR); Museo di Zoologia dell'Università, Bologna, Italy (MZUB); Museo del Dipartimento di Biologia Animale dell'Università, Catania, Italy (MBAC); Museo Nacional de Ciencias Naturales, Madrid, Spain (MNMS); Muséum National d’Histoire Naturelle, Paris, france (MNHN); Naturhistorisches Museum Mainz, Mainz, germany (NHMM); Stefano Palazzi collection, Modena, Italy (SPC); The Natural History Museum, London, UK (BMNH); Alberto Villari malacological collection, Messina, Italy (AVC); Zoologische Staatssammlung, Munich, germany (ZSMC). Petaloconchus (Macrophragma) laurae n. sp. exAMINeD MATeRIAL. Holotypus, Catania, e-Sicily, Italy: S. giovanni Li Cuti, in shallow water, on lava stones. Paratypi, same data oh holotypus, 118 empty shells and 20 little cluster (3-10 shells each); Capo Mulini village, in shallow water, on lava stones, 3 empty shell; Acitrezza village, in shallow water, on lava stones, 6 empty shells. Messina, N-e Sicily, Italy: ganzirri village, in shallow water, on stones, 2 empty shells; Siracusa, S-Sicily, Italy: Vendicari, from beached shell-grit, 6 empty shells. Agrigento, S-Sicily, Italy: Pelagie Is., Lampedusa, from beached shell-grit, 2 empty shells. Palermo, N-W Sicily, Italy: Ustica Is., from shell-grit, 25 m depth, 1 empty shell, AVC. Kosl jun, Croatia: Pag otok, in shallow water, on stones, 5 specimens and a single little cluster with living animals, SPC; Bodrum Harbour, Turkey: in shallow water, on stones, 2 empty shells, ALC. Holotype, 2 paratypes and a protoconch from the locus typicus in MNHN, (with no reg. number); 1 paratype in AMS, C.474169; 1 paratype in MNMS, n. 34393; 1 paratype in MZUB, MZB45413; 1 paratype in ZMUM, n. Lc 24964; 1 paratype in ZSMC, n. 20021768; 1 paratype in MBAC, n. MBLMC-CT78. Other paratypes in DSC. DeSCRIPTION Of HOLOTyPUS. Shell cylindrical, 16 mm in length in adult regularly coiled specimens, composed by 14 rounded, squeeze shaped whorls (figs. 1-4). The sculpture is regular: 9 spiral lines cross numerous and equally thicked (or slightly stronger) axial ribs, which form rounded and not marked tubercles at the intersection. True columellar keels are lacking, while a single faint central plait (fig. 6) is present on the columella, from earlier to the 12-13th tele-whorls of an adult specimen: this columellar chord is not visible in the last whorls. The diameter of the aperture is about 2 mm. Clusters of several specimens were found, even if true vermetid trottoir, like that of some tropical species of the same genus, are not known. The living animal (fig. 7) is pale cream in colour in the lower part of the metapodium, the anterior part of the mouth and the cephalic tentacles, the remaining part being dark brown; the podalic tentacles are almost black; the operculum (fig. 8) is thin, smooth downward, with an internal spiral keel upward: it is wide 2/3 of the total opertural diameter of the tube, and allows to see a darker upper zone of the foot. VARIABILITy. The shape of the whole shell depends on the morphology of substrate, i.e. stones and their crevices, so specimens may vary from long tricky shaped to more rounded coiled forms. Shell has the length between 12-20 mm, and shows 13-15 whorls; the shell sculpture include from 8 to 11 spiral lines cross. The color of the shell could be dark to amber brown, paler in empty shells. The columellar plait could vary in thickness depending on the shell whorls, as previously reported. eTyMOLOgy. The specific name of the species is dedicated to my wife Laura. BIOLOgy AND DISTRIBUTION. As other congenerics, the new species inhabits hard substrata of shallow waters. It was never recorded in intertidal zone. The new species has been recorded from Sicily to for the Jonic and Adriatic sea, but its distribution range could be wider. COMPARATIVe NOTeS. Numerous species of Petaloconchus are close similar in morphological characters of the shell as well as of the external soft parts. A good character to separate them is represented by the arrangement of the columellar A new species of Petaloconchus Lea, 1843 from the Mediterranean Sea (Mollusca, Gastropoda,Vermetidae) 125 figures 1-4, 6-11: P laurae n. sp. fig. 1: holotype. fig. 2: paratype, Pag otok. figs. 3-4: paratypes, S. giovanni Li Cuti. Scale bar 5 mm. fig. 6: drawing of columellar arrangement. fig. 7: external morphology of the soft parts. fig. 8: upward view of operculum. Scale bar 0,5 mm. figs. 9,10: protoconchs (0,7x0,75 mm); the black arrow indicates the basal chord. fig. 11: protoconch sculpture. figures 5, 12, 13. P. glomeratus. fig. 5: drawing of columellar arrangement. fig. 12: protoconch (1,1x0,7 mm). fig. 13: protoconch sculpture. fig. 14: sketches of columellar keels in different species, from the wall of tube (a), the columella (b), and the central fold (c). fig. 15: drawing of the columellar keels variation from earlier (c) to middle (b) and older (a) whorls in P. intortus. 126 Danilo ScuDeri structures, i.e. the columellar keels, originated from a layer of the upper/lower wall of the tube (fig. 14a) or from a layer of the columella (fig. 14b), and the central fold, which seem to originate from another distinct layer (fig. 14c). The columellar structures, were proposed by Carpenter (1856) as a species-specific discriminating character for Petaloconchus. Subsequently Mörch (1861) utilised this character to distinguish Petaloconchus from the morphologically close related Thylaeodus Mörch, 1860, currently considered a subgenus of Vermetus Cuvier, 1800, which bear a cancellated sculpture of the shell but lack internal structures, as confirmed by Scuderi (1999) for the Mediterranean Vermetus (Thylaeodus) granulatus (gravenhorst, 1831). The study here conducted on original descriptions of the 25 extant known species of this genus and directly on material of 10 of them confirmed as good the species-specific discriminating character of the columellar keels: no one of these known species show a single columellar plait alone. Moreover, internal structures in a single specimen of Petaloconchus are here observed to vary along the whole length of the tube (fig. 15), from earlier tele-whorls (fig. 15c), where they become to grow, being slightly variable (figs. 15c1, 15c2) the middle trait (fig. 15b), where they are characteristic of the species in number and arrangement, to the last whorl (fig. 15a), becoming less numerous, more faint or totally absent. Characters/species Petaloconchus laurae This could cause misunderstandings on the taxonomy of species and on the real taxonomic value of this character: Monterosato (1892), for example, following Mörch (1861), placed “Serpula” glomerata L. in Petaloconchus, but stated: “...this subdivision was founded on species which present longitudinal internal keels, which absolutely lack in all our (Mediterranean) vermetids”. The study of the material of the Monterosato collection (MCZR), which was carried out along with the present investigation, revealed on the contrary that all the specimens of P. glomeratus had keels in the middle trait of the shell. Pillai & Hove (1994) utilised the presence/absence, number and shape of internal keels as discriminating character for the taxonomy of Spiraserpula, a genus of marine sedentary Annelida, which presents analogies with Petaloconchus in shell morphology. P. laurae n. sp. is described as new on the basis of a series of morphological characters, among which the presence of a single columellar plait: no species of Petaloconchus are known wanting the columellar keels. The record of Schiaparelli (1995) for the Ligurian sea of P. glomeratus with a single internal keel is probably a not complete shell of the Linnean species, not referable to the new species. The presence of a single columellar keel and the shape and sculpture of protoconch allowed the discrimination of P. laurae n. sp. from the two morphologically closest species: the recent Mediterranean P. glomeratus, whose holotype housed in Petaloconchus glomeratus Petaloconchus intortus TeLeOCONCH number of whorls sculpture 13-15 radial equal to the spiral up to 30 20-22 radial less marked than the spiral radial less marked than the spiral columellar keels 1 3 3 opening of tube rounded squared squared rather globose pupoid pupoid dimensions (mm) 0,7 x 0,75 1,1 x 0,7 0,65 x 0,4 number of whorls 1 1/2 2 1/2 2 1/2 present absent present PROTOCONCH shape basal chord Table I. Distinguishing characters in Petaloconchus laurae, P. glomeratus and the fossil P. intortus. A new species of Petaloconchus Lea, 1843 from the Mediterranean Sea (Mollusca, Gastropoda,Vermetidae) BMNH is here compared with the new species, and the fossil P. intortus: all the others characteristics are summarised in Table I. P. glomeratus has a very characteristic protoconch (fig. 12), never reported before in literature, constituted by 2½ whorls, the apical very inflated, measuring 1,1 x 0,7 mm, with a faint sculpture on the entire surface of few spiral and more numerous axial threads which form a reticulation detectable only after SeM magnifications (fig. 13). The fossil P. intortus has a smaller protoconch, measuring 0,65 x 0,40, with 2½ whorls, the second of which higher than the previous ones: they are almost smooth and bear a single basal chord, similar to that of P. laurae n. sp. P. myrakeenae (Absalão & De Carvalho Rios, 1987), from South-eastern Brazil, is morphologically related to P. laurae n. sp., but shows two internal laminae, even if the original description is not complete, lacking further important characters, i.e. the protoconch and the external soft part morphology. P. macrophragma Carpenter, 1857 from Mexico could resemble P. laurae n. sp., but shows three columellar structures and a different protoconch. The protoconch of the Indopacific P. cereus Carpenter, 1857 presents a basal chord similar to that of the new species, but is constituted by 2 ½ whorls, is bigger (0,73 x 0,54 mm) and has a pupoid shape; the adult shell is quite different, being flat, almost smooth except for some very faint spiral lines on the upper zone of the tube, crossed by thin and often dark coloured axial threads. Two oblivious taxa could be linked to the new species: Vermetus jonicus Danilo et Sandri, 1856 is reported as a polychaete by Monterosato (1892), who observed the syntype in the NHMM; Petaloconchus (Macrophragma) flavescens (Carpenter, 1857) was reported from Sicily in the original description and Nordsieck (1968) and Parenzan (1970) listed this species among the Mediterranean Vermetidae, although firstly Mörch (1861) and later Keen (1961 e 1971), both having observed the syntype in BMNH (reg. n. 195918), reported the true Mexican distribution of this species, which is extended from Bahia San Luis gonzaga to Mazatlàn, being the Sicilian citation a mistake. Moreover, as could be argued by the original description and figures, this species, unlike P. laurae n. sp., have two internal laminae, lacking the central fold. 127 further two new species of Petaloconchus were recently described from Philippines (Kelly, 2007): P. apakadikike Kelly, 2007 and P. lilandikike Kelly, 2007 compared to P. laurae n. sp. both have two well-developed internal keel and a different protoconch. P. laurae n. sp. seems to be distributed from east to West Mediterranean, including the eastern part of the Adriatic sea. aCKnoWledGeMentS I am indebted to Ms. Kathie Way (BMNH) who kindly sent photographs of Dunker's type material, photographed by Phil Hurst. Stefano Palazzi (Modena) and Alberto Villari (Messina) loaned biological and bibliographic material. Stefano Schiaparelli (Dip.Te.Ris., University of genoa) is thanked for interesting comments and suggestions. Philippe Bouchet (MNHN), yuri Kantor (ZMUM), enrico Schwabe (ZSMC), Marco Taviani (MZUB), José Templado (MNMS) and Mandy Reid (AMS) are acknowledged for the allocation of the type material of P. laurae n. sp., bibliographic, material and suggestions. Many thanks are due to Dr. francesco Criscione (AMS) for both the english text and the bliographic assistance. reFerenCeS Absalão R.S. & De Carvalho Rios e., 1987. Petaloconchus myrakeenae, a new species of Vermetidae from brazilian waters (Mollusca: gastropoda). Revista Brasileira de Biologia, 47: 415-418. Carpenter P., 1857. first steps toward a monograph of the recent species of Petaloconchus, a genus of Vermetidae. Proceedings of the Zoological Society of London, 24(1856): 313-317. Keen A.M., 1961. A proposed reclassification of the gastropod family Vermetidae. Bulletin of the British Museum Natural History (Zoology), 7: 181-213. Keen A.M., 1971. Sea shells of tropical west America. Stanford University Press, Stanford, 1064 pp. Kelly III W. C., 2007. Three new vermetid gastropod species from guam. Micronesica, 39: 117-140. Monterosato T. di Maria di, 1892. Monografia dei Vermeti del Mediterraneo. Bullettino della Società malacologica italiana, 17: 7-48. Mörch O.A.L., 1859. etudes sur la famille des vermets. Journal de Conchiliologie, 7: 342-360. 128 Danilo ScuDeri Mörch O.A.L., 1860. etudes sur la famille des vermets. Journal de Conchiliologie, 8: 27-48. Mörch O.A.L., 1861-62. Review of the Vermetidae (Part I-II-III), Proceedings of the Zoological Society of London, 28 (1861): 145-181; 28 (1861): 326-365; 28 (1862): 54-83. Nordsieck, f. 1968. Die europäischen Meeres-gehäuseschnecken (Prosobranchia). Vom eismeer bis Kapverden und Mittelmeer. gustav fischer Verlag, Stuttgart, 273 pp. Parenzan P., 1970. Carta d'identità delle conchiglie del Mediterraneo, vol. I. Bios Taras, Taranto, 283 pp. Pillai T.g. & Hove H.A. ten, 1994. On recent species of Spiraserpula Regenhardt, 1961, a serpulid polychaete genus hitherto known only from Cretaceous and Tertiary fossils. Bulletin of the British Museum Natural History (Zoology), 60: 39-104. Schiaparelli S. 1995. Contributions to the knowledge of Vermetidae (Mollusca, gastropoda) from the Ligurian Sea. Bollettino Malacologico, 31: 267-276. Scuderi D., 1999. Contributo alla conoscenza dei Vermetidae mediterranei: Vermetus granulatus (gravenhorst, 1831) e suoi principali morfotipi. Bollettino Malacologico, 35: 45-48.