''Powellisetia paroeca'' is an extinct

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

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 ...

in the family

Rissoidae Rissoidae is a large family of sea snails. Members of the Rissoidae are very small in size and possess an operculum. Distribution and habitat Rissoidae are found worldwide. They live on sandy or gravel bottoms among algae or marine plants. Th ...

. First described by

Harold John Finlay Harold John Finlay (22 March 1901 – 7 April 1951) was a New Zealand palaeontologist and conchologist. Biography Finlay was born in Comilla, India (now Bangladesh), on 22 March 1901, to a family of Baptist missionaries. He was left a paraple ...

in 1924, it is known to have lived in New Zealand during the early

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Taxonomy

The species was identified in 1924 by

as a subspecies of ''

Powellisetia prisca ''Powellisetia'' is a genus of minute sea snails, marine gastropod mollusks or micromollusks in the family Rissoidae. Species Species within the genus ''Powellisetia'' include: * '' Powellisetia australis'' (Watson, 1886) * '' Powellisetia bil ...

'', and later described as a species in its own right.

Description

Finlay described both ''Powellisetia paroeca'' and ''Powellisetia prisca'' as follows: Finlay noted some differences between the two groups, namely that ''Powellisetia paroeca'' "...differs from the species only in slightly higher spire and more regularly curved outer lip, which slants downwards from suture without any medial angulation."

Distribution

Fossils of the species have only been identified in

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. The holotype was collected from sandstone at Calamity Point in

Clifden Clifden () is a coastal town in County Galway, Ireland, in the region of Connemara, located on the Owenglin River where it flows into Clifden Bay. As the largest town in the region, it is often referred to as "the Capital of Connemara". Frequen ...

, Southland, which dates to the early Miocene era.

References

Rissoidae Gastropods described in 1924 Gastropods of New Zealand Extinct animals of New Zealand Miocene animals of Oceania Miocene extinctions Prehistoric gastropods Molluscs of the Pacific Ocean Taxa named by Harold John Finlay {{paleo-gastropod-stub