Amphidromus perversus

• Amphidromus perversus butoti Laidlaw & Solem, 1961 • Amphidromus perversus kadatuaensis Dharma, 2007 • Amphidromus perversus emaciatus (von Martens, 1867) (uncertain > taxon inquirendum, based on invalid original name; no replacement name has been proposed) • Amphidromus perversus natunensis Fulton, 1896 • Amphidromus perversus perversus (Linnaeus, 1758) • Amphidromus perversus siglerae Thach, 2018 ;Synonyms: • Amphidromus perversus melanomma (Pfeiffer, 1852): synonym of Amphidromus melanomma (L. Pfeiffer, 1852) • Amphidromus perversus rufocinctus Fruhstorfer, 1905: synonym of Amphidromus perversus (Linnaeus, 1758) (junior homonym, invalid: not Fulton, 1896) == Distribution ==

Distribution of Amphidromus perversus include Sumatra and Java to Borneo, Sulawesi and Bali. Absent from the Mentawi Chain and Panaitan Island. Its occurrence on Sumbawa needs confirmation. Probably it has been introduced into Singapore. Subspecies recognized here are from Great Natuna, Bawean, Kangean Islands and Riau Islands. == Shell description ==

Amphidromus perversus are amphidromine (left-handed and right-handed snails occur in the population). • Amphidromus perversus perversus f. niveus P. & F. Sarasin, 1899 is snow-white with a black varix and black mark behind the peristome. It is an "albino" perversus which is common in the Celebes and sporadically seen from Java and Borneo. • Amphidromus perversus perversus f. obesus von Martens, 1867, is an unfigured variety which probably can be equated with squat individuals of the typical perversus pattern. • Amphidromus perversus perversus f. perversus Linnaeus, 1758, is a solid yellow shell with black varix and narrow black band behind the peristome. It is known from the whole range of the species. • Amphidromus perversus perversus f. strigosus von Martens, 1867, has continuous, rather narrow, straight brown bands running from the suture to the bottom of the whorl. It is known from Bali, Borneo, and Celebes. • Amphidromus perversus perversus f. sultanus Lamarck, 1822, has wavy brown bands running over the entire whorl. The bands are interrupted in the middle of the whorl by a narrow spiral band of the ground color. This variation is found in all parts of the species range. == Amphidromus perversus butoti ==

of Amphidromus perversus butoti Holotype: Zoological Museum in Amsterdam. The type locality is Bajutan, Kangean Islands. Collected by Hoogerwerf on August 20, 1954. Description: A brilliantly colored series of populations with highly polished shell surface. The general intensity of the coloration and the strong polish are the only features separating this race from the other subspecies. Remarks: The problem of how to treat insular populations which show minor divergence from the main stocks is far from being satisfactorily settled. The intense coloration of the Kangean populations shows a minor difference from the main populations and Laidlaw & Solem (1961) have recognized it with a subspecific name. For purposes of future reference, they selected as holotype a shell with a color pattern quite distinct from any which have been named. Thus, the name butoti can at least be used for the color variation if it is decided to include the Kangean populations in the nominate form of perversus. Besides the nominate color pattern of butoti, shells referable to the infraviridis, infrapictus, rufocinctus, sultanus and typical perversus pattern were seen on Kangean Island. Paratypes: Specimens were seen from several localities on Kangean Island. The shells from Sepandjang are in Chicago Natural History Museum, no. 97808, in the Zoological Museum in Amsterdam, and in Butot; Djukung specimens are in the Zoological Museum in Amsterdam; and topotypes from Bajutan are in Chicago Natural History Museum, no. 97806, and in Butot and the Zoologisch Museum, Amsterdam, Some additional material from Kangean Island (USNM 468416, Paravicini!) was seen after the description had been written. == Amphidromus perversus emaciatus ==

Range: Central and East Java, possibly Bali. == Amphidromus perversus melanomma ==

Range: Riau Archipelago near Singapore and possibly Perak and Biliton Island off Borneo. Remarks: The purple apex, the numerous wavy brown flammulations that are partially interrupted by a yellow peripheral color band, and the solid shell are characteristic. This variety is similar to sultanus, but has only partial interruption of the stripes by the color band and has the purple apex. The Biliton record from the early Samarang voyage is questionable, and it is quite possible that the Perak records of De Morgan are in error. The only certain localities are the Singapore area and Riau Archipelago. == Amphidromus perversus natunensis ==

Range: Great Natuna Islands; possibly the South Natuna and Anamba Islands also. The yellow peripheral band of melanomma is absent; otherwise this is close to the Riau population. Amphidromus perversus natunensis is quite variable in color, ranging from white to dark (see Pilsbry 1900, pp. 162–163). Possibly some of the material that Jacobi (1895) dissected under the names Amphidromus interruptus and Amphidromus chloris belongs here, but the shells were not figured and their location is unknown. The South Natuna Island record needs confirmation, while specimens from Siantan, Anamba Islands (CNHM 72427), are referred by Laidlaw & Solem (1961) with some hesitation. == Amphidromus perversus rufocinctus ==

Range: Bawean Island, Java. This weakly characterized race differs primarily by its intense color, strong color zone, and slight white margin at the suture. Of seventeen shells collected in May, 1954, by Hoogerwerf at Telaga Kastoba, Bawean Island, ten were dextral and seven sinistral. Three lacked a varix, one was grass green in color, three were whitish, and thirteen had yellow ground color. The name sankapurus Fruhstorfer, 1905, refers to white shells with a very dark color band. This variation is similar to Amphidromus perversus butoti. ==References==