THE NAUTILUS 112(4):l()y-112, 199^ Page 109

A New Species of Land Snail of the Genns (: Hydrocenidae) from the Phihppine Islands

Kurt Auffenberg

Division ot Invertebrate Paleoiitolog)' Florida Museum ot Natural History Uuiversitv ot F"lorida Gainesville, FL 32611 USA kauffe(S'HMuili.uH.edn

ABSTRACT The type-series and other specimens e.xamined are de- posited in the Philippine National Museum (PNM) and is described from an isolated lime- Gforissa cavini new species Florida Museum of Natural Histon', Universitv of Flor- stone outcrop in the northeastern extremitv ot Panav Island. ida (UF). Philippine Islands. The new species is characterized by its rel- atixelv large size and sliell sculpture of weak spiral threads SYSTEMATICS which become increasingly oblicjue below the peripheiy. It is most similar to Georissn coccinra Quadras and Moellendortt. Class Gastropoda Cuvier, 1797 1895 from Ma.sbate Island. Philippine Islands. Georissa cveri'tii Superlamily Neritoidea Rafinesque, 1815 1895 from Sarawak has a similar shell, but much E. A. Smith, Family Ilvdrocenitlae Troschel, 1856 stronger shell sculpture. Genus Georissa Blantord, 1864 Key Words: Hydrocenidae. Georissa. new species, Philippine Georissa cavini new species Islands, Panav Island, Ma.sbate Island. (Figures I, 3, 5, 6)

Description: Shell (Figure 1) medium-sized for genus INTRODUCTION (mean = 2.4 mm length, 1.8 mm width), turbinitorm, ratio length/width about 1.33. Shell with 3.6 whorls. Em- The author conchicted a .survey of the terrestrial niol- bryonic bulbous; subsecjuent whorls convex. Su- kisks of Panay Island, Visavan Islands, in the central tures deeply impressed; sutural channel thstinct on early Phihppines, during April-May, 1992. Fiftv-five sites were whorls, occasionidlv becoming very shallow on last hall sampled, with emphasis on the small species found in whorl. Sculpture of embryonic yvhorls a fine mesh oi the widespread limestone areas of Panay and its satellite pits. Teleoconch glossy, with growth threads of variable islands. strength, crossed by e.xtremeh' fine obh(jue spiral threads Onl\ al)out 52 species and sulispecies ot terrestrial that become increasingly oblique below periphery. mollusks have been recorded from Panay (Bartsch, 1919, Groyvth striations more distinct on body whorl; spiral 1938, 1939, 1942; Moellendorff, 1898; Smith, 1932a, b). threads stronger on upper whorls (Figure 3). Aperture

This is a small mmiber, when compared to landmasses subovate, ratio aperture lengtli/shell length about 0.42. of similar size in the Philippines. However, much of the Parietal wall King at an angle of about 27-38° (mean = island consists ot low, rolling hills (noyv mostly converted 34°) to iLxis of shell; plane of aperture in lateral profile to agriculture), which do not provide the varied habitats at about 28-34° (mean = 31°) to shell axis. Umbilical of other areas of the Philippines. Substantial elevations area indented; basal area with y\ide concave columellar and a greater dixersitv ot habitats ta\()ralile to terrestrial shield; edge of basal fip extending to left in an arc, form- mollusks occur only in the extreme western portion of ing thin, but prominent ridge terminating in umliilical the island. Most t;L\a previously recorded from Panay are resiion, borderinti columellar shield on left. Umbihcal still extant, but their chstributions are now restricted to callus concave to very slightly- c(3n\ex. Peristome thick- small plots of remnant forest, except those of the com- ened internally, usually more so near base ot parativeh' pristine higher elevations (> 8()()m) in the and upper insertion (Figure 1). Outer lip slightly sinuose west. Few undescribed species were encountered. Geo- in lateral profile. Shell color Imck-red to orange, usually- rissa is a common faunal component throughout the more intense on ; inner edge ot fip and insertion

Phihppines, vet all specimens of this genus found in Pa- area with rose red border in live-collected specimens. nay belong to a single, undescrilied species. This new (Figure fi) calcareous, concentric with sub- species is here named and described. central nucleus. Inner surface with relatively long, slen- Page 110 THE NAUTILUS, Vol. 112, No. 4

Figures l-(>. Cforissa cavini new .species and G. coccinea Quadras and Moellendorff, LS95. 1, 3. C. cavini. holuhpe, 2.3 mm length, PNM-CO 39481. 2, 4. G. coccinea, 1.8 mm length. UF 87296. 5. G. cavini. parahpe, jinenile, 1.3 mm length, UF 250000. 6. G. cavini, internal surface of operculum, parat\pe, 0.9 mm opercnhnii length, UF 267482. K. Auffenberg, 1998 Page 111

Tabic 1. Adult .shell measurements (mm. converted from oc- ular iincronieter nnjt.s) of .selected .specimens ofGcorissa cavini new species (holot\pe in parentheses) and Georissn corciiwn (UF ST29fiV L = lenijth, W = width. Ap = aperture Page 112 THE NAUTILUS, Vol. 112, No. 4

all phases of the survey. Robert S. Kennetlv, Cincinnati Bartsch, P 1939. A synopsis of the Philippine land moliusks of Museum of Natural Historv, initiated the Philippine Bio- the subgenera Lamarckiella and Pararyssota of the genus cli\ersit\' Iu\enton Project, which was luntled tliroutjli Rtjssota. Proceedings of tlie Biological Societ\' of Wasli- ington 52:41-56. generous support troni the John D. and Catherine T. Bartsch, P. 1942. A synopsis of the Philippine land Uioliusks of Mac-Arthur Foundation. Luis A. Ruedas, Museum of the genus Hcmitrichia. Proceedings of the Biological So- Southwestern Biolog\', University' of New Mexico, facil- ciety of Washington 55:27^4. itated many aspects of the fieldwork. Many persons in Moellendorff O. v. 1898. Verzeichniss der auf den Pliilippinen the Philippine Department (A En\ironnient and Natural lebenden Landmollusken. Abhandlungen der natnrtor- Resources, Protected Areas and Wildlife Bureau deserve schende Gesellschaft zu Gorlitz 22:26-208. acknowledgment for their assistance with logistics and Quadras F. F. \\ Moellentlorff 1895. spe- J. and O. Diagnoses collecting permits. SEM micrographs were made with ciennn no\anmi e.\ insniis Philippinis. Nachrichtsblatt der an Hitachi S-41.5A scanning electron in microscope the deutschen Malakozoologischen Gesellschaft. 27(.5-6):7.3- Department of Zoologv, Uni\ersit)' of Floriila Tins field- 88. work was conducted with financial support from the Smith, M. 19.32a. Notes upon Philippine land shells with de- Thomas L. McGintv Endowment Fund, University of scriptions of new forms. Tlie Nautilus 45(3): 102-104. pis. Florida Foundation. 7-8. Smith, M. 19.32h. New Philippine Island land shells. The Nau- LITERATURE CITED tilus 46(2):62-65, pi. 4. Thompson, F. G. and S. P. Dance. 1983. Non-marine moliusks

Bartsch, P. 1919, Critical remarks on Pliilippine landsliells vvitli of Borneo. II Pulmonata: Pupillidae, Clausiliidae. Ill descriptions ot new forms. Proceedmgs of the Biological Prosobranchia: Hydrocenidae, Helicinidae. Bulletin of the Sot'iet\- of Washington .32:15-20. Florida State .Vluseum. Biological Sciences 29(3):I01-152.

Bartsch, P. 19.38. A synopsis of the Philippine land moliusks of Zilch. A, 1973, Die T\pen and Tvpoide des Natur-Museums

the subgenus Rijssota. Proceedings of the Biological So- Senckenberg, 52). : Hydrocenidae. Archi\' fiir ciety of Washington 51;101-120. Molhiskenkunde 103(4/6):263-272.