''Eupera trolobia'' is a species of

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

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 and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

). The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

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 nor a syntype). Of ...

MZSP 155716. All were discovered in eastern subterranean

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

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 ** Thin-shell structure Science Biology * Seashell, a hard ou ...

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

{{Taxonbar, from=Q111820139 Sphaeriidae Bivalves of North America Molluscs of South America Cave animals Bivalves described in 2022