''Eupera troglobia'' is a species of

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

that lives in caves. The discovery of ''E. troglobia'' makes it the first troglobitic bivalve from the Americas (

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

). The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

collected was named holotype MZSP 155717 and the

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype (biology), isotype ...

MZSP 155716. All were discovered in eastern subterranean

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

at Casa Pedra cave 10°49'28.4''S, 49°37'16.5''W. Records of the species date back to 2006 in the technical report of Brazil's National Center of Cave Exploration and Conservation.

Description

''Eupera trolobia'' adults are ~ in length and lack pigmentation in the soft parts and shell. The wall of the

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

is thin, making it fragile. It is translucent with a bit of light yellow or light greenish yellow. The anterior edge is rounded and smaller than the posterior edge. In medium specimens, the ventral edge is rounded and is slight ascentent to larger specimens. The sculpture of uniform concentric growth lines around ~15 per millimeter. The growth lines are usually continuous from the anterior up to the posterior hinge region.

References

Sphaeriidae Bivalves of North America Molluscs of South America Bivalves described in 2022 Cave molluscs {{Sphaeriidae-stub