EMERSON AnewspeciesofMorum APEX 10(2-3): 95-98,20 sept. 1995. Description of a new species ofMorum from the Indian Océan (Gastropoda: Harpidae) EMERSON William K. AmericanMuséum ofNatural History, Central Park West at 79th Street, NewYork, NewYork, 10024, USA KEYWORDS: Gastropoda, Harpidae,Morum, new species, Indian Océan. ABSTRACT. Morum (Oniscidia) vicdani new species is described from 12-200 m off Saya de Malha Bank, Indian Océan {ca. 10°30'S, 62°25'E) and compared with congeners. INTRODUCTION lagoon at about 80-100 m. depth by RTV IKHTlANDRm 1989." A number of new species and otherwise interesting discoveries of mollusks hâve been Morum (Cancellomorum) sp. SiRENKO, made in récent years by Russian and Japanese 1995: 11, 16, fig. 14. commercial fisheries opérations and biological A spécimen, illustrated in color, was m océanographie surveys undertaken on or near reported from a depth of 12 on the Saya de Saya de Malha Bank (ca. 10°30'S, 62°25'E) in Malha Bank. the western Indian Océan (cf Bouchet and Diagnosis: Similar to Morum (Oniscidia) Bail, 1991; Okltani, 1991; Emerson and grande (A Adams, 1855: 185), but M. vicdani Sage, 1991; Bondarev and Roeckel, 1992; BONDAREV, 1995; Sirenko, 1995). n. sp difîers in having a more fusiform outline and a much less dense shell, with fewer a.xial Through the good offices of Donald Dan, ribs (10 to 12 vs. 17 to 19) and a thinner, less spécimens of an unnamed species of Morum pustulated pariétal shield, and with the exterior were submitted to the author for study. I take edge oftheouter lip non-crenulate at maturity. pleasure in describing this new species in honor of Victor Dan of Manila, Philippines, a Matermiaml Examined: Holmomt\pe, (Figs.(A3,MN4)H, 59.5 in length, 36.2 in width connoisseurofOld World mollusks. mm n° 226517); Paratype 1, (Figs. 5, 6), 57.0 in Abbreviations used for institutions: length, 33,1 mm in width (AMNH n° 226518); AMNH = American Muséum of Natural Parat>pe 2, (Figs. 1, 2), 47.1 mm in length, 28.0 Histor>, New York, USA; mm in width (AMNH n° 226519). Only a very BM(NH) = British Muséum of Natural Histon. few other spécimens of this taxon are known [now The Natural Histor> Muséum], London, and thèse are in private collections (teste England. Donald Dan). SYSTEMATIC TREATMENT Type Locality: Trawled off Saya de Malha Bank, Indian Océan in ca. 200 m, in 1986 Family HARProAE Brown, 1849 (holot>pe). ^ Subfamily MORUMINAE Description: Spire raised, shell inflated, & Hughes Emerson, 1987 thin, elongately fusiform with cancellate Genus Morum Rôding, 1798 sculpture. The 10 spiral ribs on the body whorl Subgenus Oniscidia Môrch, 1852 more prominent than the 10 to 12 axial ribs, Morum vicdani, new species forming blunt spmes at the mtersections and with fine axial threads crossing the interspaces (Figs. 1-6) and spiral ribs. Outer lip weakly reflexed, Morum (Oniscidia) cf grande (A. Adams, marginal edge smooth, not crenulate. with 1855), Bondarev, 1995: 48, 49, fig. 3; [not irregularly placed plications on the inner edge. Morumgrande (A. Adams, 1855)]. Pariétal callus thin with irregularly placed Two spécimens, one of which was pustules on the marginally raised shield. illustrated in color, were reported "... to hâve Protoconch of 2 1/2 smooth whorls. The five been dredged from the [Saya de Malha] bank postnuclearwhorls cancellate. Base colorwhite 95 . APEX 10(2-3):9S-98,20 sept 1995 AnewspeciesoiMorum EMERSON Figures 1-6. (opposite) Morum vicdani, new species. 1,2, Paratype 2, AMNH n* 226519. 3, 4, Holotype, AMNH n' 226517, 5. 6. Paratype 1, AMNH n° 226518. AH figures xi with 4 tanish brown, discontinuous spiral bands Straits of Formosa, ofif Taiwan (Emerson, in the form of isolated, narrow, irregular, bar- 1985: 54). With the description of Morum like axial Unes on the body whorl; aperture vicdani n. sp., 17 species of Morum (16 in white. The spiral color bands are weakly Oniscidià, 1 inHerculea Hanley, 1858) are now defined in some spécimens. No soft parts recognized as living in the Indo-west Pacific available for study. biogeographic région (E.merson, 1990: 150). Discussion: The new species and Morum {Oniscidià) praeclarum Melvill, 1919, from ofif Somalia, Mozambique and the Seychelle Islands, are the only species oîMorum known to be living on the African lithospheric plate (cf. Emerson, 1990: 152). Morum grande, in Acknowledgements: I am indebted to Donald contrast, occurs from southern Japan to the Dan of West Friendship, Mar>land for his Philippine Islands, Indonesia, and SE Australia contributions to this study and for generously on the Eurasian, Philippine and Indo-Australian donating the t>pe si>ecimens to the AMNH. I plates, respectively. Tvvo morphological forms thank m\ AMNH colleagues Christopher B. of M. grande bave been recognized: a stout Boyko and Kathleen Sarg for technical obèse shell is more commonly foimd in the assistance, Andrew S. Modell for photographie northern part of the range (Emerson 1985, pi. ser\ices and Stéphanie Crooms for word- 2, figs. 1, 2) and a larger, more elongate shell is processing the manuscript. more frequently encountered in Australian waters (Emerson, 1985. pi. 2, figs. 3, 4). The taxonomic significance ofthis shell dimorphism has yet to be determined. The new species more closely resembles in outline the southern form (WiLSON et al., 1994: 139, pi. 30, figs. 1, 4). The northeMrn form is represented by the lectotype of grande (Yen. 1942: 214, pi. 17, fig. 104) from the "China Seas." The lectotjpe is BM(NH) (n° 1966726) (Dance and Emerson mm 1967: 95) and measures 61.0 in length and mm 53.8 in width (Emerson, 1985: 54). Morum grande has been confiised with M. (^Oniscidià) cancellatum (Sowerby, 1824: pi. 233, figs. 1-3; Emerson, 1985: 52, pi. 1, figs. 17, 18 = lectotype, BM(NH) n° 197744), but mm differs in its larger size (attaining 75 in length), higher spire, more numerous axial ribs, more narrowly spaced spiral cords and a wider expansion of the outer lip. Morum cancellatum is distributed from southern Japan to the Philippine Islands, the East and South China Seas, and is aiso known from the Fiji Islands (Emerson, 1990: 152). The t>pe locality is the 96 EMERSON AnewspeciesoïMorum APEX 10(2-3): 95-98,20 sept. 1995 97 APEX 10(2-3):95-98, 20 sept 1995 AnewspeciesoïMontm EMERSON REFERENCES Adams, a. 1855. Descriptions ofnew gênera of Emerson, W. K. & W. E. Sage, 111 1991. The gasteropodous [sic] Mollusca. Proc. Zool. Soc. mystery ofthe mislocalized Indian Océan Soc. London 21(259): 182-186. volute, DallivolutasurinamensisOkutani. Hawaiian ShellNews 39(8): 3,4. BoNDAREV, I. 1995. Saya de Mahla [sic] again. 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