Isolation and Evolution of the Amphidromus in Nusa Tenggara
by Richard L. Goldberg & Mike Severns

ACKNOWLEDGEMENTS:
The authors would like to thank Dr. Gary Rosenberg of the Academy of Natural Sciences, Philadelphia, for his guidance in developing the evolutionary aspects of this article; Dr. Tim Pearce of the Delaware Museum of Natural History, for his substantive comments and encouragement during the article preparation; and to Lynn Scheu, Am. Conch. editor, for injecting her expertise and guidance in the writing and preparation of the article.

Photo Credits: (MS) = Mike Severns; (RG) = Richard Goldberg. Green background = volcanic islands, blue background = limestone islands.

REFERENCES:
- Goldberg, R.L. 1993. Variation In The Genus Amphidromus. Am. Conch, Vol. 21, No. 1. p. 5.
- Haniel, C.B. 1921. Variationsstudie an timoresischen Amphidromusarten. Zeitschrift fur Induktive Abstammungsund Vererbungslehre, Bd. XXV, Heft 1/2. p. 1-88.
- Laidlaw, F.F. & Solem, A. 1961. The Land Snail Genus Amphidromus-A Synoptic Catalogue. Fieldiana: Zoology, Vol. 41, No. 4. 1961. p. 569-572.
- Pilsbry, H.A. 1900. Manual of Conchology, Second Series, Vol. 13. p. 209-212.
- Richardson, L. Camaenidae: Catalog of Species. Tryonia, No. 12. p. 5-49.
- Rolle, H. Neue. 1903. Amphidromus-Formen. Nachrbl. D. Mal. Ges. 35 (9/10). p. 156-157.
- Solem, A. 1974. Character Weighting In Land Snail Classification. Bulletin of the Amercian Malacological Union. p. 47-50.
- Whitten, Mustafa, & Henderson. The Ecology of Sulawesi. Gadjah Mada University Press.
- Zilch, A. 1953. Die Typen und Typoide des Natur-Museums Senckenberg, 10: Mollusca, Pleurodontidae (1) Amphidromus. Arch. Moll., Bd. 82, (4/6). p. 131-140.

ABOUT THE AUTHORS:
Richard L. Goldberg is a mail order shell dealer with a strong interest in terrestrial, as well as marine shells. He has authored many popular articles on land shells. His photographs of living exotic snails have appeared in books and magazines, and his slide presentations on conchology are familiar to many shell clubs around the country. He is a Past President of COA, Past Editor of the COA Bulletin (currently American Conchologist), and Past Publications Chair of COA. Rich's professional background is as a television writer/producer/ director (he produced the first one hour television magazine-format video dealing with conchology.) His recent introduction to Indonesia has convinced him to spend more time researching the variability of Amphidromus.

Mike Severns is a professional underwater photographer, and owner of a dive operation in Maui, Hawaii. Severns' pictures have appeared in many international magazines, and publications along with two books of his underwater photography. He is also a biologist with a particular fascination for land mollusks. Over the past 16 years Severns has made the first comprehensive study of the distribution, taxonomy, and morphology of the arboreal genus Partulina in the rugged West Maui mountains of Hawaii (see Islands magazine, February 1997, "Maui on the Wild Side"). During his field research on Maui, he has uncovered the bones of 36 extinct flightless birds, one of which is named after him. For the past several years he has been exploring little known islands in Indonesia in search of unusual or rare forms of Amphidromus.

GLOSSARY:
Anomaly: Deviation or departure from normal order; peculiar, irregular, abnormal, or difficult to classify.
Biota: The combined flora and fauna of a region.
Competition: The simultaneous demand by two or more organisms for limited environmental resources, such as nutrients, living space, or light.
Divergence: In biology, the evolutionary tendency or process by which animals or plants that are descended from a common ancestor evolve into different forms when living under different conditions.
Endemic: Native to or confined to a certain region.
Genetic Drift: Random fluctuations in the frequency of the appearance of a gene in a small, isolated population, presumably owing to chance rather than natural selection.
Intra-population variability: Variation of a species within one population or one habitat.
Inter-population variability: Variation of a species in distinct populations throughout its geographical range.
Natural Selection: The process in nature by which, according to Darwin's theory of evolution, only the organisms best adapted to their environment tend to survive and transmit their genetic characters in increasing numbers to succeeding generations while those less adapted tend to be eliminated.
Niche: a. The function or position of an organism or a population within an ecological community. b.The particular area within a habitat occupied by an organism.
Nominate: adj. Pertaining to the subspecies that has the same name as the species -- in this case, Amphidromus inconstans inconstans.
Norm: A standard, model, or pattern regarded as typical.
Paradigm: An example that serves as pattern or model.
Population: Related to ecology, all the organisms that constitute a specific group or occur in a specified habitat.
Polymorphic: Having different forms among the organisms of a single species, independent of sexual variations.
Preoccupied: Already used and therefore unavailable for further use. Used of taxonomic names.
Sympatric: Occupying the same or overlapping geographic areas without interbreeding. Used of populations of closely related species.
Whimsical: Erratic in behavior or degree of unpredictability.

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