Snails of the world:Asia:the tropical region This region includes India,Sri Lanka,to Burma and Thailand,China,Taiwan and Japan(south of Yesso).Included here are also The Andaman and Nicobar islands,The Philippines and Indonesia. In this huge part of the world two marked influences are noticable:an Indian and a Chinese. The Indian part of this region includes India south of the Himalayas,with Burma and Assam.Sri Lanka and The Andaman and Nicobar Islands form part of this region too. A very distinctive family in this region is Helixarionidae,with about 200 species living here.A lot of these species live in relatively small areas. Only a few species of the Streptaxidae are to be found here.There is a variable presence of operculate snails,with about 200 species.For example Japonia,Leptopomoides,Nicida and Diplommatina,the last two belonging to the smaller types of snails. The Acavidae can only be found on Madagascar and on the Islands of the Indian Ocean. They lay very big eggs,in the case of Acavus waltoni they are as big as a third of the shells diameter.Not surprisingly there are only 3-4 being laid. Acavus sp. Aulopoma sphaeroideum Aulopoda is endemic to Sri Lanka. In the eastern part of this region there are a number of districts:Upper Burma,Pegu, Tenasserim and Arakan.Some genera not found in India are present here.Sesara and Sophina are members of the Helixarionidae family.Also living here is Hypselostoma,Rhaphaulus and Pollicaria.The Helicinidae family is represented by Calybium and Pleuropoma.
The Siamese region includes Thailand,Cambodia,Laos and Vietnam.The Streptaxidae are very well represented here with circa 30 species.Another family is the Camaenidae,about 36 species live in this region.Especially Amphidromus is a well known genus. Amphidromus furcilla(photo:Femorale) The Bradybaenidae and Helixarionidae have also a large number of genera in this region. More than 100 species of operculate snails are present here,for example Cyclophorus,Rhiostoma and Pterocyclos.
The Malay region includes all the Sunda Islands,The Moluccas and of course Malaysia. This is a huge area but has relatively few distinctive species.The Helixarionidae is well represented here,with for example the genus Dyakia.Also Asperitas is a well known genus.The Parmarioninae have their centre here. Asperitas polymorpha,photo:Korina Sangiouloglou. Parmarion martense
Amphidromus of the Camaenidae family is present here too,most of the species are sinistral. Paraphaedusa of the Clausiliidae family has a few species living in this region. More than 100 species of operculate snails live in Borneo alone.The Cochlostomatidae is a very distinct family with the genus Ophisthostoma. Crossopoma species are to be found in Borneo and Sumatra. Ophisthostoma tiesenhansemi Ophisthostoma linterae Crossopoma cornuvenatorium">
The Philippine region has a very large number of species with a huge variety.The Helicostylinae,a subfamily of the Bradybaenidae, has ten genera with depressed shells with a keel(Calocochlea),globose shells(Helicostyla)or elongated shells (Chrysallis,Phengus and Canistrum). The Camaenidae have quite a few species of the genus Obba,which are endemic.The shells are shaped like a lens, brownish with white or yellow blotches,or with banding. Again the family Helixarionidae has members here,two genera are Lepidotrichia and Rhyssota.They have big shells measuring between 30 and 120 mm,and are caught for food or bait.The subfamily Parmarioninae has two genera,Parmunculus and Philippinella which mantle completely covers their reduced shells. There are a huge number of operculate snails living in this region.For example Cyclo- phorus,Cyclotus,Pupina. Helicostyla electrica Helicostyla florida photo(c)Charles J. Geerts photo(c)Schoener specimen shells