''Amphidromus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of tropical air-breathing land snails,

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

pulmonate gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

s in the family

Camaenidae Camaenidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea, the typical snails and their allies. This is one of the most diverse families in the clade Stylommatophora. Thes ...

. The shells of ''Amphidromus'' are relatively large, from to in maximum dimension, and particularly colorful. During the 18th century, they were among the first

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

n land snail shells brought to Europe by travelers and explorers. Since then, the genus has been extensively studied: several comprehensive monographs and catalogs were authored by naturalists and zoologists during the time period from the early 19th to the mid 20th centuries. Modern studies have focused on better understanding the

evolutionary relationships Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation te ...

within the group, as well as solving

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. A ...

problems. The genus ''Amphidromus'' is unusual in that it includes species that have dextral shell-coiling and species that have sinistral shell-coiling. In addition, some species within this genus are particularly notable because their populations simultaneously include individuals with left-handed and right-handed shell-coiling. This is an extremely rare phenomenon, and very interesting to biologists. Studies focused on the soft anatomy of ''Amphidromus'' are scattered and fragmentary. Information on the internal anatomy is known only from a few species, and no larger, comparative morphological study has ever been carried out. Species in the genus ''Amphidromus'' are

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose num ...

— in other words, they are tree snails. However, more detailed information on their habits is still lacking. The general feeding habits of these snails are unknown, but a few species are known to feed on microscopic

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

lichens A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.terrestrial algae. ''Amphidromus'' themselves are preyed upon by birds, snakes, and probably also by smaller mammals such as rats.

Taxonomy and history

The generic name is derived from the

ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

words ' (), meaning "on both sides", and ' (), meaning "running", alluding to the different chiralities of the shells. The shells of ''Amphidromus'' are relatively large, and quite colorful; considerable numbers of them were among the first

n land snail shells brought back to Europe by travelers and explorers during the 18th century. Comparatively speaking, malacologists have gathered a much smaller number of specimens. Several species and

forms Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens. Form also refers to: *Form (document), a document (printed or electronic) with spaces in which to write or enter data * ...

were described before 1800, most of them with inadequate locality data. At least two names — ''

Amphidromus laevus ''Amphidromus laevus'' is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Camaenidae Camaenidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the s ...

'' (Müller, 1774) and the form ''

A. perversus A is the first letter of the Latin and English alphabet. A may also refer to: Science and technology Quantities and units * ''a'', a measure for the attraction between particles in the Van der Waals equation * ''A'' value, a measure o ...

'' f. ''aureus'' Martyn, 1784 – still (as of 2017) have not yet been reported from a precise locality. During the first half of the nineteenth century, many species and varieties were named, again usually with poor locality data. Not until Eduard von Martens (1867) published his monograph was there an attempt to cover the entire complex of species within this genus. The 1867 monograph contained considerable information both on the variation within the genus, and on the problems of the

geographic distribution Geography (from Ancient Greek, Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, i ...

of the species. Many concepts that originated with von Martens are still (as of 2017) in use. In 1896,

Hugh Fulton Hugh may refer to: *Hugh (given name) Noblemen and clergy French * Hugh the Great (died 956), Duke of the Franks * Hugh Magnus of France (1007–1025), co-King of France under his father, Robert II * Hugh, Duke of Alsace (died 895), modern-day ...

organized 142 specific and varietal names into eighteen species groups containing a total of 64 species. When

Henry Augustus Pilsbry Henry Augustus Pilsbry (7 December 1862 – 26 October 1957) was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a cent ...

's 1900 monograph ''

Manual of Conchology George Washington Tryon Jr. (20 May 1838 – 5 February 1888) was an American malacologist who worked at the Academy of Natural Sciences in Philadelphia. Biography George Washington Tryon was the son of Edward K. Tryon and Adeline Savidt. ...

Pilsbry H. A. Henry Augustus Pilsbry (7 December 1862 – 26 October 1957) was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a cent ...

(1900). ''

, structural and systematic, with illustrations of the species. Second series: Pulmonata''
Volume 13
Australasian Bulimulidae: ''

Bothriembryon ''Bothriembryon'' is a genus of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Bothriembryontidae. B. J. Smith (1992) made the last review of the genus summarizing all known data. Distribution T ...

'', ''

Placostylus ''Placostylus'', or flax snails, are a genus of very large, air-breathing land snails, terrestrial pulmonate gastropod molluscs in the family Bothriembryontidae.MolluscaBase eds. (2020). MolluscaBase. Placostylus H. Beck, 1837. Accessed throu ...

''. Helicidae: ''Amphidromus''. 253 pp., 72 plates
page 184
appeared, the number of species in the genus ''Amphidromus'' had increased to 81, and these were placed in nineteen groups. Pilsbry's study has remained the only illustrated monograph of the genus, and it is still considered indispensable for any serious study of the genus. Since 1900, the major

studies on ''Amphidromus'' have been faunistic (a study of the fauna of some territory or area) in scope. The papers of American malacologist

Paul Bartsch Paul Bartsch (14 August 1871 Tuntschendorf, Silesia – 24 April 1960 McLean, Virginia) was an American malacologist and carcinologist. He was named the last of those belonging to the "Descriptive Age of Malacology". Early life Bartsch emigrate ...

(1917, 1918, 1919) on the Philippine species,

Bernhard Rensch Bernhard Rensch (21 January 1900 – 4 April 1990) was a German evolutionary biologist and ornithologist who did field work in Indonesia and India. Starting his scientific career with pro-Lamarckian views, he shifted to selectionism and became on ...

(1932) on the

Lesser Sunda Islands The Lesser Sunda Islands or nowadays known as Nusa Tenggara Islands ( id, Kepulauan Nusa Tenggara, formerly ) are an archipelago in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make u ...

forms, and

Tera van Benthem Jutting TERA is a shielded twisted pair connector for use with Category 7 twisted-pair data cables, developed by The Siemon Company and standardised in 2003 by the International Electrotechnical Commission (IEC) with the reference IEC 61076-3-104. Th ...

(1950, 1959) van Benthem Jutting T. (1950). "Critical studies of the Javanese pulmonate land-shells of the families Helicarionidae, Pleurodontidae, Fruticicolidae and Streptaxidae". ''Treubia'' 20(3): 381–505, 107 figs. on Javan and Sumatran populations are especially comprehensive. Potentially the most valuable contribution is that of

Curt Haniel Kurt is a male given name of Germanic or Turkish origin. ''Kurt'' or ''Curt'' originated as short forms of the Germanic Conrad, depending on geographical usage, with meanings including counselor or advisor. In Turkish, Kurt means "Wolf" and is ...

(1921), Haniel C. (1921). "Variationsstudie an Timoresischen ''Amphidromus'' Arten". ''Zeits. Induct. Abstamm. und Vererbungsl.'' 25(1–2): 88 pp., 5 plates. who discussed the variation within '' A. contrarius'' and '' A. reflexilabris'' on

Timor Timor is an island at the southern end of Maritime Southeast Asia, in the north of the Timor Sea. The island is divided between the sovereign states of East Timor on the eastern part and Indonesia on the western part. The Indonesian part, al ...

; the variations in color and form were well illustrated in a series of color plates. Literature published after 1900 contains many scattered descriptions of new color forms and subspecies. Of the 309 names in the nomenclatural list, 111 (35.9%) were published after Pilsbry (1900).