Scutalus mariopenai 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 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...

, 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 Orthalicidae

Orthalicidae

Orthalicidae are a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks are classified in the informal group Sigmurethra of the clade Stylommatophora...

.

The specific name mariopenai honours Mario Peña González, a malacologist from Lima

Lima

Lima is the capital and the largest city of Peru. It is located in the valleys of the Chillón, Rímac and Lurín rivers, in the central part of the country, on a desert coast overlooking the Pacific Ocean. Together with the seaport of Callao, it forms a contiguous urban area known as the Lima...

 and tutor of the second author. The specific epithet is a noun

Noun

In linguistics, a noun is a member of a large, open lexical category whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition .Lexical categories are defined in terms of how their members combine with other kinds of...

 in the genitive case

Genitive case

In grammar, genitive is the grammatical case that marks a noun as modifying another noun...

.

Distribution

The distribution of Scutalus mariopenai includes Peru. The type locality is Catzcal (09°54’43’S 077°49’40’W), Ancash Region

Ancash Region

Ancash is a region in northern Peru. It is bordered by the La Libertad region on the north, the Huánuco and Pasco regions on the east, the Lima region on the south, and the Pacific Ocean on the west. Its capital is the city of Huaraz, and its largest city and port is Chimbote...

, Peru. Type specimens are stored in the Netherlands Centre for Biodiversity Naturalis

Naturalis

Naturalis is the national natural history museum of the Netherlands, based in Leiden. It originated from the merger of the Rijksmuseum van Natuurlijke Historie and the Rijksmuseum van Geologie en Mineralogie in 1984. In 1986 it was decided that the museum had to become a public museum and a new...

, Leiden, the Netherlands, and in the private collection of V. Mogollón Avila, Lima, Peru.

Description

Scutalus mariopenai is characterized by the broadly expanded and callous lip, the fine, punctuate granulation, and the whitish-corneous ground colour, with four brown spiral bands on the last whorl.
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...

 height is up to 41.1 mm, 1.65 times as long as wide, umbilicate and deeply perforated, conical, with slightly convex sides and solid. Ground colour is uniformly whitish-corneous, the upper 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...

 are lighter, with four spiral light chestnut-brown bands, a small one below the white-lined suture, two broader ones above and below the periphery (which in some specimens are faintly subdivided into two equally broad bands) and a fourth band encircling the umbilicus. The surface is lustreless, with growth striae and spiral lines of fine, punctuate granulation, starting shallowly on the postnepionic whorl, but becoming rapidly more conspicuous on the following and fading away inside the umbilicus. The protoconch

Protoconch

A protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...

 is pit-reticulate. The shell has 6.3 whorls that are somewhat convex. The last whorl is saccate. The suture is impressed, somewhat crenulate, at the aperture ascending in front. 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 large, ovate, glossy white inside with the pattern visible in banded specimens. Apertural margins are converging. The aperture is 1.30 times as long as wide, 0.70 times the total height. The peristome is broadly expanded and backwardly reflexed, glossy whitish. Columellar margin is straight, broadly expanded and merging into the rather thick parietal callus.

The height of the shell is 36.7–41.1 mm. The width of the shell is 21.9–36.2 mm. The shell has 6-6.5 mm.

Dimensions of the holotype

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

 are as follows: The height of the holotype is 41.1 mm. The width of the shell is 26.2 mm. The height of the aperture is 22.6 mm. The with of the aperture is 17.9 mm. The height of the last whorl is 29.6 mm. The shell has 6.3 whorls.
Type material: apertural and abapertural views of two shells of Scutalus mariopenai showing its color variability:
Living animal is whitish- to pale-grey, with a dark-greyish band along the foot. Tentacles are dark-grey near the eye-tips, lighter at the base.

This species is closely allied to Scutalus ortizpuentei Weyrauch, 1967 which was described from Dept. Cajamarca

Cajamarca

Cajamarca may refer to:Colombia*Cajamarca, Tolima a town and municipality in Tolima DepartmentPeru* Cajamarca, city in Peru.* Cajamarca District, district in the Cajamarca province.* Cajamarca Province, province in the Cajamarca region....

, Río Chancay valley, between Chiclayo

Chiclayo

Chiclayo is the capital city of the Lambayeque region in northern Peru. It is located 13 kilometers inland from the Pacific coast and 770 kilometers from the nation's capital, Lima...

 and Chota

Chota, Peru

Chota is a town in Northern Peru, capital of the province Chota in the region Cajamarca. The city is the seat of the Territorial Prelature of Chota....

, 80 km north of Quinden (ca. 06°38’S 079°05’W) in Peru. It differs from this species by being smaller (41 vs. 48 mm shell height), having a smaller aperture, and the lip more broadly expanded. The faintly visible subdivision of the spiral bands around the periphery, visible in some specimens of Scutalus mariopenai, resembles the more pronounced colour pattern in Scutalus ortizpuentei. It may also be compared to Scutalus cretaceus (Pfeiffer, 1855) from which it differs by being less elongate, having a stronger sculpture

Sculpture (mollusc)

The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...

on the last whorl, having the inside of the aperture whitish coloured; having the lip more broadly expanded.