Inchoatia
Encyclopedia
Inchoatia is a genus
of air-breathing land snail
s, terrestrial
pulmonate gastropod mollusks in the family Clausiliidae
, the door snails.
similar. They all have slender to very slender, small to medium-sized shells
with more or less prominent papillae along the suture. The clausilial apparatus
is of the so-called "N-type", with a lamella spiralis and a plica principalis. As in genus Albinaria
, the genital tract
shows a dimorphism in penial structure, with either a papilla or a caecum.
areas of the central and western part of mainland Greece, where some taxa are restricted to high altitudes.
The genus Inchoatia was introduced by Gittenberger & Uit de Weerd (2006) on the basis of molecular phylogenetic analyses by Uit de Weerd et al. (2004). This molecular phylogenetic study by Uit de Weerd et al. (2004) was not designed to answer questions about the status of the species group taxa within Inchoatia.
The fact that the Inchoatia taxa are very disjunctly distributed
means that attempting to discriminate species as against subspecies is even more of a subjective opinion than usual, because reproductive isolation
under natural conditions cannot be observed. An objective or a generally accepted method to weigh morphological differences does not exist. DNA analyses may be extremely helpful, but cannot always be considered decisive with regard to species or subspecies status. Molecular phylogeny
reconstructions made clear that reproductive isolation and lineage splitting do not always run entirely parallel, resulting in paraphyletic species. In Inchoatia, with some island-like distributions of presumably high alpine taxa, this may also be the case.
Besides synapomorphic nucleotide
substitutions, these taxa share a similar shell shape, and have more or less continuous ranges
. According to the molecular data, the major division within Inchoatia is between an Inchoatia inchoata + "Inchoatia regina" subclade
, and an Inchoatia haussknechti + Inchoatia megdova subclade. This pattern is congruent with genital anatomical differences between the two subclades, previously used to place them in separate genera Sericata and Carinigera and with conchological similarities between the species within each subclade.
The molecular phylogenetic relationships between nominal (sub)species within genus Inchoatia were examined by Uit de Weerd et al. (2009). A cladogram
based on sequences of cytochrome-c oxidase I
(COI) genes showing phylogenic relations of Inchoatia by Uit de Weerd et al. (2009) (simplified):
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of air-breathing land snail
Land snail
A land snail is any of the many species of snail that live on land, as opposed to those that live in salt water and fresh water. Land snails are terrestrial gastropod mollusks that have shells, It is not always an easy matter to say which species are terrestrial, because some are more or less...
s, terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
pulmonate gastropod mollusks in the family Clausiliidae
Clausiliidae
Clausiliidae, common name door snails, are a taxonomic family of small, very elongate, mostly left-handed, air-breathing land snails, sinistral terrestrial pulmonate gastropod mollusks....
, the door snails.
Description
The species classified within the genus Inchoatia are conchologicallyConchology
Conchology is the scientific or amateur study of mollusc shells. Conchology is one aspect of malacology, the study of molluscs, however malacology studies molluscs as whole organisms, not just their shells. Conchology pre-dated malacology as a field of study. It includes the study of land and...
similar. They all have slender to very slender, small to medium-sized shells
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
with more or less prominent papillae along the suture. The clausilial apparatus
Clausilium
The clausilium is a calcareous anatomical structure which is found in one group of air-breathing land snails: terrestrial pulmonate gastropod mollusks in the family Clausiliidae, the door snails...
is of the so-called "N-type", with a lamella spiralis and a plica principalis. As in genus Albinaria
Albinaria
Albinaria is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Clausiliidae, the door snails.- Distribution :Distribution of the genus Albinaria include:* southern Albania* Greece* Cyprus...
, the genital tract
Reproductive system of gastropods
The reproductive system of gastropods varies greatly from one group to another within this very large and diverse taxonomic class of animals...
shows a dimorphism in penial structure, with either a papilla or a caecum.
Distribution
The species within this genus occur in limestoneLimestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
areas of the central and western part of mainland Greece, where some taxa are restricted to high altitudes.
Taxonomy
Some Inchoatia taxa were insufficiently known, even conchologically (in terms of a shell description) and were classified without clear reference to the underlying facts. In the past (Nordsieck 1972, Nordsieck 1974, Zilch 1981) species of the Alopiinae were classified in the genusCarinigera or Sericata, mainly on the anaotmical basis of having either a penial papilla or a caecum. This dogmatic approach led to a grouping together of clausiliid species with very different shells, which was eventually unmasked as unnatural by DNA analyses. This position is however not embraced by Nordsieck (2007), who lumped together several genus-group taxa, which “can be characterized neither by shell nor by genital characters”, in his view.The genus Inchoatia was introduced by Gittenberger & Uit de Weerd (2006) on the basis of molecular phylogenetic analyses by Uit de Weerd et al. (2004). This molecular phylogenetic study by Uit de Weerd et al. (2004) was not designed to answer questions about the status of the species group taxa within Inchoatia.
The fact that the Inchoatia taxa are very disjunctly distributed
Disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
means that attempting to discriminate species as against subspecies is even more of a subjective opinion than usual, because reproductive isolation
Reproductive isolation
The mechanisms of reproductive isolation or hybridization barriers are a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not...
under natural conditions cannot be observed. An objective or a generally accepted method to weigh morphological differences does not exist. DNA analyses may be extremely helpful, but cannot always be considered decisive with regard to species or subspecies status. Molecular phylogeny
Molecular phylogeny
Molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree...
reconstructions made clear that reproductive isolation and lineage splitting do not always run entirely parallel, resulting in paraphyletic species. In Inchoatia, with some island-like distributions of presumably high alpine taxa, this may also be the case.
Besides synapomorphic nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
substitutions, these taxa share a similar shell shape, and have more or less continuous ranges
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
. According to the molecular data, the major division within Inchoatia is between an Inchoatia inchoata + "Inchoatia regina" subclade
Subclade
In genetics, subclade is a term used to describe a subgroup of a subgenus or haplogroup. It is commonly used today in describing genealogical DNA tests of human mitochondrial DNA haplogroups and human Y-chromosome DNA haplogroups....
, and an Inchoatia haussknechti + Inchoatia megdova subclade. This pattern is congruent with genital anatomical differences between the two subclades, previously used to place them in separate genera Sericata and Carinigera and with conchological similarities between the species within each subclade.
The molecular phylogenetic relationships between nominal (sub)species within genus Inchoatia were examined by Uit de Weerd et al. (2009). A cladogram
Cladogram
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 cytochrome-c oxidase I
Main subunit of cytochrome c oxidase
Cytochrome C and Quinol oxidase polypeptide I is main subunit of cytochrome c oxidase complex.Cytochrome c oxidase is a key enzyme in aerobic metabolism. Proton pumping heme-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes...
(COI) genes showing phylogenic relations of Inchoatia by Uit de Weerd et al. (2009) (simplified):
Species
According to the Gittenberger & Uit de Weerd (2009) and Uit de Weerd et al. (2009) the genus Inchoatia include 3 species:- Inchoatia haussknechtiInchoatia haussknechtiInchoatia haussknechti is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Clausiliidae, the door snails.- Description :...
(O. Boettger, 1886) - synonym: Carinigera haussknechti- Inchoatia haussknechti haussknechti (O. Boettger, 1886)
- Inchoatia haussknechti alticola (Nordsieck, 1974)
- Inchoatia haussknechti hiltrudae (Nordsieck, 1974)
- Inchoatia haussknechti orina (Westerlund, 1894)
- Inchoatia haussknechti refuga (Westerlund, 1894)
- Inchoatia haussknechti semilaevis (O. Boettger, 1889)
- Inchoatia inchoataInchoatia inchoataInchoatia inchoata is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Clausiliidae, the door snails.- Description :...
(O. Boettger, 1889) - type species, synonym: Sericata inchoata- Inchoatia inchoata inchoata (O. Boettger, 1889)
- Inchoatia inchoata klemmi (Nordsieck, 1972)
- Inchoatia inchoata paramythica (Nordsieck, 1974)
- Inchoatia inchoata regina (Nordsieck, 1972)
- Inchoatia megdovaInchoatia megdovaInchoatia megdova is a species of air-breathing land snail, terrestrial pulmonate gastropod mollusk in the family Clausiliidae, the door snails.-Description:...
(Nordsieck, 1974) - synonym: Carinigera megdova- Inchoatia megdova megdova (Nordsieck, 1974)
- Inchoatia megdova bruggeni Gittenberger & Uit de Weerd, 2009
- Inchoatia megdova palatalifera (Hausdorf, 1987)
- Inchoatia megdova tavropodensis (Fauer, 1993)