Pachychilidae
Encyclopedia
Pachychilidae, common name pachychilids, is a taxonomic family
of freshwater snail
s, gastropod molluscs in the clade
Sorbeoconcha
.
s with a worldwide distribution in the tropics. Representatives are found in South
and Central America
, Africa
, Madagascar
, South and South-east Asia
and tropical Australia
(Queensland
: Torres Strait Islands
).
, which is concentric and multispiral.
, which is a brackish water snail found in estuaries and other coastal habitats. Pachychilids are either oviparous
(laying eggs), oviviviparous
or viviparous (retaining developing eggs and youngs in special incubatory structures).
Most 20th century authors did not recognize Pachychilidae as an independent family, but affiliated species under different groups, such as Thiaridae
and Pleuroceridae
. However, recent revisions based on molecular and morphological evidence have proven their independent and distinct status from the former.
This family has no subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005
).
based on sequences of mitochondrial 16S ribosomal RNA
sequences showing phylogenic relations of Pachychilidae:
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
of freshwater snail
Freshwater snail
A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....
s, gastropod molluscs in the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
Sorbeoconcha
Sorbeoconcha
Sorbeoconcha is a taxonomic clade of snails, i.e. gastropods, mainly marine species with gills and opercula, within the clade Caenogastropoda.The taxon Sorbeoconcha was named by Winston Ponder and David R. Lindberg in 1997.-1997 taxonomy:...
.
Distribution
Pachychilids are freshwater snailFreshwater snail
A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....
s with a worldwide distribution in the tropics. Representatives are found in South
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, South and South-east Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
and tropical Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
(Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
: Torres Strait Islands
Torres Strait Islands
The Torres Strait Islands are a group of at least 274 small islands which lie in Torres Strait, the waterway separating far northern continental Australia's Cape York Peninsula and the island of New Guinea but Torres Strait Island known and Recognize as Nyumaria.The islands are mostly part of...
).
Description
Pachychilids have an operculumOperculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
, which is concentric and multispiral.
Ecology
All species inhabit freshwater except Faunus aterFaunus ater
Faunus ater is a species of brackish water snail with an operculum, an aquatic gastropod mollusk in the family Pachychilidae.Faunus ater is the only species within the genus Faunus.- Distribution :...
, which is a brackish water snail found in estuaries and other coastal habitats. Pachychilids are either oviparous
Oviparity
Oviparous animals are animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, reptiles, all birds, the monotremes, and most insects, some molluscs and arachnids....
(laying eggs), oviviviparous
Ovoviviparity
Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...
or viviparous (retaining developing eggs and youngs in special incubatory structures).
Taxonomy
The name is derived from a combination of the words 'pachy' (Greek = thick) and the suffix '-chilus' (Greek = Lip), meaning 'thick lipped' - with respect to the thickened aperture of the shell in some species.Most 20th century authors did not recognize Pachychilidae as an independent family, but affiliated species under different groups, such as Thiaridae
Thiaridae
Thiaridae, common name thiarids, is a family of tropical freshwater snails with an operculum, aquatic gastropod mollusks in the superfamily Cerithioidea....
and Pleuroceridae
Pleuroceridae
Pleuroceridae, common name pleurocerids, is a family of small to medium-sized freshwater snails, aquatic gilled gastropod mollusks in the superfamily Cerithioidea.These snails have an operculum and typically a robust high-spired shell....
. However, recent revisions based on molecular and morphological evidence have proven their independent and distinct status from the former.
This family has no subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005
Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)
The taxonomy of the Gastropoda as it was revised by Philippe Bouchet and Jean-Pierre Rocroi is currently the most up-to-date overall system for classifying gastropod mollusks...
).
Genera
Genera within the family Pachychilidae include:- BrotiaBrotiaBrotia is a genus of Southeast Asian freshwater snails, gastropod molluscs in the in taxonomic family Pachychilidae.- Distribution :Species of Brotia occur in freshwater habitats of Southeast Asia, ranging from Northern India in the west through to Sumatra in the east...
H. Adams, 1866 - Doryssa Swainson, 1840
- Faunus de Montfort, 1810 with the only species Faunus aterFaunus aterFaunus ater is a species of brackish water snail with an operculum, an aquatic gastropod mollusk in the family Pachychilidae.Faunus ater is the only species within the genus Faunus.- Distribution :...
(Linnaeus, 1758) - JagoraJagoraJagora is a genus of freshwater snails which have an operculum, aquatic gastropod mollusks in the family Pachychilidae.- Distribution :This genus is endemic to the Philippines.- Species :Species within the genus Jagora include:...
Köhler & Glaubrecht, 2003 - Madagasikara Köhler & Glaubrecht, 2010 - synonym: MelanatriaMelanatriaMadagasikara is a genus of tropical freshwater snails with an operculum, aquatic gastropod molluscs in the family Pachychilidae.The generic name Madagasikara is from the Malagasy language and means "Madagascar".This genus is endemic to Madagascar....
Bowdich, 1822 auctt. - PachychilusPachychilusPachychilus, common name jute snails, is a genus of freshwater snails with an operculum, aquatic gastropod mollusk in the family Pachychilidae.Pachychilus is the type genus of the family Pachychilidae.- Distribution :...
I. Lea & H. C. Lea, 1851 - type genus of the family Pachychilidae - Paracrostoma Cossmann, 1900
- Potadoma Swainson, 1840
- Pseudopotamis Martens, 1894
- SulcospiraSulcospiraSulcospira is a genus of freshwater snails which have an operculum, aquatic gastropod mollusks in the family Pachychilidae.- Distribution :The distribution of this genus includes: Malaysia, China, Thailand, Indonesia, and Vietnam.- Species :...
Troschel, 1858 - synonym: Adamietta Brandt, 1974 - Tylomelania Sarasin & Sarasin, 1897
Cladogram
A cladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
based on sequences of mitochondrial 16S ribosomal RNA
16S ribosomal RNA
16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...
sequences showing phylogenic relations of Pachychilidae:
Further reading
- Köhler F., von Rintelen T., Meyer A. & Glaubrecht M. (2004). "Multiple origin of viviparity in southeast Asian gastropods (Cerithioidea: Pachychilidae) and its evolutionary implications". EvolutionEvolution (journal)Evolution, the International Journal of Organic Evolution, is a leading monthly scientific journal that publishes significant new results of empirical or theoretical investigations concerning facts, processes, mechanics, or concepts of evolutionary phenomena and events. Evolution is published by...
58(10): 2215-2226. doi:10.1554/04-344.