Strobilopsidae
Encyclopedia
Strobilopsidae is a family
of air-breathing land snail
s, terrestrial
pulmonate gastropod mollusks in the superfamily Pupilloidea
.
, itself belonging to the clade
Stylommatophora
within the clade Eupulmonata
(according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005
).
The family Strobilopsidae has no subfamilies according to the taxonomy of the Gastropoda by Bouchet & Rocroi (2005)
.
Some authors put family Spelaeodiscidae
as a subfamily of Strobilopsidae.
is trochiform, dome-shaped or discoidal and umbilicate. The shell has from 4½ to 6 slowly-enlarging whorls
. The aperture
is small, oblique, with armature of 2 or 3 parietal lamellae and several deeply-placed basal folds, all growing continuously from an early neanic stage. The peristome is more or less thickened and expanded, the ends of the lip remote, joined by a parietal callus.
The shell, aside from its helicoid shape (not a character of great importance), differs from all Pupillidae in the arrangement of the lamellae and baso-palatal folds. In multidentate Pupillidae the five primary teeth are always recognizable while in Strobilops only the main parietal lamella and the columellar lamella can certainly be said to correspond, and these are found in so many other land shells that their occurrence is not especially significant. It is possible, however, that upper and lower palatal folds of Pupillidae are represented by teeth 5 (the most right basal tooth) and 2 (second left basal tooth), and the basal fold by tooth 1 (the most left basal tooth).
By the accelerated lamellae and folds of the shell, which appear early in the neanic stage, Strobilops resembles various Tornatellininae (within Achatinellidae
). In that family both parietal and palatal folds or laminae are sometimes present in the neanic stage. Various pupillid genera also, such as Orcula
(Orculidae
) and Lauria (Lauriidae
), have apertural armature during the neanic stage. Orcula has spiral parietal and columellar lamellae but no basal or palatal folds. Lauria has basal folds, but they are spaced, transverse barriers, wholly unlike the adult basal or palatal armature of the species, and differing equally from the folds of immature Strobilops, which from their inception appear to develop continuously into those of the adult shell. It appears likely that the acceleration or early appearance of apertural armature in Tornatellininae, Orcula, Lauria and Strobilops has been independent in the four groups, and is not indicative of direct relationship between any of them.
lies very near the last part of the intestine
.
Digestive system
: The jaw has numerous ribs. Radula
with tricuspid central tooth with square basal plate, as large as the bicuspid laterals, the marginals multicuspid.
Reproductive system
: Ovotestis
forms two groups of follicles. Penis is continued in a long epiphallus and bears a long appendix, with swollen basal and distal divisions, the penial retractor bifurcate, one branch inserted on the epiphallus, the other on the base of the appendix (distally it attaches to the right ocular retractor, according to G. Dallas Hanna).
By the structure of the male organs Strobilops
resembles Vallonia
, Pupilla
, Lauria
, the Achatinellidae
, and some other groups are similar in having a bifurcate penial retractor and a long, tripartite appendix. If G. Dallas Hanna is right in stating that
the penial retractor is a branch of the right ocular band, this is an important difference from any known Orthurethra
. The mouth parts do not differ materially from some Pupillidae.
, the last one in the Upper Pliocene (Astian stage) of Piedmont
.
In late Cretaceous
beds there are various forms described as Helix, or under the names Obbinula and Pseudostrobilus, which certainly have some of the characters of Strobilops. All are larger than any Strobilops.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
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 superfamily Pupilloidea
Pupilloidea
The Pupilloidea are a superfamily of air-breathing land snails, terrestrial gastropod mollusks in the informal group Orthurethra.-Taxonomy:This superfamily contains the following families:*Family Pupillidae*Family Argnidae*Family Chondrinidae...
.
Taxonomy
The Strobilopsidae family is classified within the informal group OrthurethraOrthurethra
Orthurethra is a clade of terrestrial pulmonate gastropods .In the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, Orthurethra is treated as an informal group and subclade of Stylommatophora.- Taxonomy :...
, itself belonging to 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...
Stylommatophora
Stylommatophora
Stylommatophora is a taxon of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs. This taxon is currently considered to be a clade. It was previously regarded as an infraorder...
within the clade Eupulmonata
Eupulmonata
The Eupulmonata is a taxonomic clade of air-breathing snails. The great majority of this group are land snails and slugs, but some are marine and some are saltmarsh snails that can tolerate salty conditions.-Linnean taxonomy:...
(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...
).
The family Strobilopsidae 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...
.
Some authors put family Spelaeodiscidae
Spelaeodiscidae
Spelaeodiscidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks.- Taxonomy :The Spelaeodiscidae family is classified within the informal group Orthurethra, itself belonging to the clade Stylommatophora within the clade Eupulmonata .The family Spelaeodiscidae has...
as a subfamily of Strobilopsidae.
Genera
Genera within the family Strobilopsidae include:- Coelostrobilops Pilsbry, 1931
- Discostrobilops Pilsbry, 1927
- Nesostrobilops Pilsbry, 1931
- EnteroplaxEnteroplaxEnteroplax is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Strobilopsidae.- Species :The genus Enteroplax includes the following species:* Enteroplax boholensis - from Bohol, Philippines...
Gude, 1899 - EostrobilopsEostrobilopsEostrobilops is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Strobilopsidae.- Species :The genus Eostrobilops includes the following species:* Eostrobilops coreana Pilsbry, 1927...
Pilsbry, 1927 - StrobilopsStrobilopsStrobilops is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Strobilopsidae.- Species :The genus Strobilops includes the following species:* Strobilops aeneus Pilsbry - Bronze pinecone snail...
Pilsbry, 1893 - type genus of the family Strobilopsidae
Shell description
The shellGastropod 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...
is trochiform, dome-shaped or discoidal and umbilicate. The shell has from 4½ to 6 slowly-enlarging whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
. The aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is small, oblique, with armature of 2 or 3 parietal lamellae and several deeply-placed basal folds, all growing continuously from an early neanic stage. The peristome is more or less thickened and expanded, the ends of the lip remote, joined by a parietal callus.
The shell, aside from its helicoid shape (not a character of great importance), differs from all Pupillidae in the arrangement of the lamellae and baso-palatal folds. In multidentate Pupillidae the five primary teeth are always recognizable while in Strobilops only the main parietal lamella and the columellar lamella can certainly be said to correspond, and these are found in so many other land shells that their occurrence is not especially significant. It is possible, however, that upper and lower palatal folds of Pupillidae are represented by teeth 5 (the most right basal tooth) and 2 (second left basal tooth), and the basal fold by tooth 1 (the most left basal tooth).
By the accelerated lamellae and folds of the shell, which appear early in the neanic stage, Strobilops resembles various Tornatellininae (within Achatinellidae
Achatinellidae
Achatinellidae is a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Achatinelloidea.- Taxonomy :...
). In that family both parietal and palatal folds or laminae are sometimes present in the neanic stage. Various pupillid genera also, such as Orcula
Orcula
Orcula is a genus of very small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Orculidae.- Species :Species within the genus Orcula include:* Orcula austriaca* Orcula dolium* Orcula fuchsi...
(Orculidae
Orculidae
Orculidae is a family of mostly minute, air-breathing, land snails; terrestrial pulmonate gastropod mollusks in the order Pulmonata.- Taxonomy :...
) and Lauria (Lauriidae
Lauriidae
Lauriidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks.- Taxonomy :The Lauriidae family is classified within the informal group Orthurethra, itself belonging to the clade Stylommatophora within the clade Eupulmonata .The family Lauriidae has no...
), have apertural armature during the neanic stage. Orcula has spiral parietal and columellar lamellae but no basal or palatal folds. Lauria has basal folds, but they are spaced, transverse barriers, wholly unlike the adult basal or palatal armature of the species, and differing equally from the folds of immature Strobilops, which from their inception appear to develop continuously into those of the adult shell. It appears likely that the acceleration or early appearance of apertural armature in Tornatellininae, Orcula, Lauria and Strobilops has been independent in the four groups, and is not indicative of direct relationship between any of them.
Anatomy
The urethraUrethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...
lies very near the last part of the intestine
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
.
Digestive system
Digestive system of gastropods
The digestive system of gastropods has evolved to suit almost every kind of diet and feeding behavior. Gastropods as the largest taxonomic class of the mollusca are very diverse indeed: the group includes carnivores, herbivores, scavengers, filter feeders, and even parasites.In particular, the...
: The jaw has numerous ribs. Radula
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
with tricuspid central tooth with square basal plate, as large as the bicuspid laterals, the marginals multicuspid.
Reproductive system
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...
: Ovotestis
Ovotestis
An ovotestis is a gonad with both testicular and ovarian aspects. In humans, ovotestes are an anatomical abnormality associated with gonadal dysgenesis.- In gastropods :...
forms two groups of follicles. Penis is continued in a long epiphallus and bears a long appendix, with swollen basal and distal divisions, the penial retractor bifurcate, one branch inserted on the epiphallus, the other on the base of the appendix (distally it attaches to the right ocular retractor, according to G. Dallas Hanna).
By the structure of the male organs Strobilops
Strobilops
Strobilops is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Strobilopsidae.- Species :The genus Strobilops includes the following species:* Strobilops aeneus Pilsbry - Bronze pinecone snail...
resembles Vallonia
Vallonia
Vallonia is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Valloniidae.- Species :Species in the genus Vallonia include:* Vallonia allamanica* Vallonia costata Vallonia is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in...
, Pupilla
Pupilla
Pupilla is a genus of minute air-breathing land snails, terrestrial pulmonate gastropod mollusks or micromollusks in the family Pupillidae.The genus Pupilla is known from the Oligocene to the Recent period.-Species:...
, Lauria
Lauria
Lauria is a city and comune of Basilicata, Italy, in the province of Potenza, situated near the borders of Calabria.It is a walled town on the steep side of a hill with another portion in the plain below.-History:...
, the Achatinellidae
Achatinellidae
Achatinellidae is a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Achatinelloidea.- Taxonomy :...
, and some other groups are similar in having a bifurcate penial retractor and a long, tripartite appendix. If G. Dallas Hanna is right in stating that
the penial retractor is a branch of the right ocular band, this is an important difference from any known Orthurethra
Orthurethra
Orthurethra is a clade of terrestrial pulmonate gastropods .In the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, Orthurethra is treated as an informal group and subclade of Stylommatophora.- Taxonomy :...
. The mouth parts do not differ materially from some Pupillidae.
Fossil distribution
Strobilopsidae appeared in the Upper Eocene of western Europe in several species having all the external characters of the genus Strobilops, and though the internal structure has not been worked out (in 1927), it is safe to assume that they are closely related to the well-known Oligocene forms following them. In Europe this genus continued in numerous species into the PliocenePliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
, the last one in the Upper Pliocene (Astian stage) of Piedmont
Piedmont
Piedmont is one of the 20 regions of Italy. It has an area of 25,402 square kilometres and a population of about 4.4 million. The capital of Piedmont is Turin. The main local language is Piedmontese. Occitan is also spoken by a minority in the Occitan Valleys situated in the Provinces of...
.
In late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
beds there are various forms described as Helix, or under the names Obbinula and Pseudostrobilus, which certainly have some of the characters of Strobilops. All are larger than any Strobilops.
Further reading
-
Pilsbry H. A.Henry Augustus PilsbryHenry Augustus Pilsbry 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 century...
(1908). "Notes on genus Strobilops" The Nautilus 22(8): 78-80.