Megalobulimus popelairianus
Encyclopedia
Megalobulimus popelairianus, synonym Strophocheilus popelairianus, is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of tropical air-breathing land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, a 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 mollusk in the family Strophocheilidae
Strophocheilidae
Strophocheilidae is a taxonomic family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Acavoidea .- Subfamilies and genera :...

.

Distribution

Megalobulimus popelairianus occurs in Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, in Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

 (doubtful) and in Brazil.

Shell description

The shell
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...

 is very large, solid, rimate, ovate-conic. The spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

 is subregularly tapering and the penultimate whorl is somewhat bulging. The last whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...

 is depressed on the back. The color of the shell is dark reddish-brown or rich chestnut with narrow darker streaks and a lighter margin below the suture. The earlier whorls are dull reddish. The apex
Apex (mollusc)
Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...

 is white. The surface is covered with a strong cuticle, shining. Nepionic shell is distinctly marked, with 4 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...

, sculptured with strong narrow radial riblets, which on fourth whorl become obsolete toward suture below. Succeeding whorls 2, having growth-wrinkles and a dense but rather irregular spiral granulation which fades out upon last whorl, which is more coarsely sculptured by lengthwise wrinkles and has generally more or less- coarse spiral malleation. Sutures are deep, the last decidedly more oblique.

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 about half the shell's length, trapezoidal, white with a livid tint within. Outer lip is well reflexed, white (or light-brown edged), convexly curved. Columella is white, reflexed, and in the immediate vicinity of its insertion spreading upon the whorl and continued in a strong white callus across the parietal wall. Near the upper termination of parietal callus there are usually one or two low callous nodules.

The width of the adult shell varies from 85 to 98 mm, the height from 136-155 mm.

Eggs

Megalobulimus popelairianus has the largest eggs of all land gastropods. The size of the egg is 51 × 35 mm (see also Stanlen 1917).

Further reading

Stanlen R. 1917. On the calcareous eggs of terrestrial Mollusca. Journal of Conchology 15: 154-164.
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