Praenuculinae is an extinct

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

of prehistoric

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Praenuculidae Praenuculidae is an extinct family of prehistoric bivalves in the superfamily Nuculoidea. Praenuculidae species lived from the early Ordovician, Arenig stage through the Early Devonian Emsian stage.

. Praenuculinae species lived from the

middle Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Ma (milli ...

through the

late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding ...

.The Paleobiology Database Praenuculinae entry
accessed 5 February 2012.The Paleobiology Database ''Praenucula'' entry
accessed 5 February 2012. Praenuculinae fossils are found in Europe, Africa, North America and South America,The Paleobiology Database Praenuculidae entry
accessed 24 January 2012. and species are thought to have been stationary attached to substrate in shallow infaunal marine water environments where they formed shells of an

aragonite Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation fr ...

composition. The subfamily Praenuculinae was named by Teresa M. Sánchez in 1999.

Description

The majority of Praenuculidae genera possess teeth with a chevron concavity that faces towards the outer sides of the shell and a chevron point facing the umbo. These genera are grouped into the larger subfamily, Praenuculinae. Three of the genera in the family are placed into the second subfamily, Concavodontinae, based on the teeth having chevron concavities which face in the reverse, towards the center of the hinge and points facing the outside edges of the shell. Praenuculinae is composed of eleven described genera including '' Praenucula'', the type genus for the family. ''Praenucula'' is composed of six species found across Europe, in northwestern Africa, and Argentina. Three of the genera, '' Cuyopsis'', '' Trigonoconcha'', and '' Villicumia'' are

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

and known only from the

Argentine Argentines, Argentinians or Argentineans are people from Argentina. This connection may be residential, legal, historical, or cultural. For most Argentines, several (or all) of these connections exist and are collectively the source of their ...

precordillera Precordillera is a Spanish geographical term for hills and mountains lying before a greater range, similar to foothills. The term is derived from ''cordillera'' (mountain range)—literally "pre-mountain range"—and applied usually to the Andes. ...

. The monotypic '' Fidera'' was first described in 1977 by John Pojeta & Joyce Gilbert-Tomlinson and is known only from Tasmania. '' Ledopsis'' was named in 1884 and is restricted to Ordovician sediments exposed in Europe. Leo Pfab in 1934 erected the genus '' Praeleda'' from bohemian fossils which had been placed as the species ''Nucula compar'' by

Joachim Barrande Joachim Barrande (11 August 1799 – 5 October 1883) was a French geologist and palaeontologist. He was particularly known for his work on trilobites, published in the ''Systéme Silurien de la Bohéme'' which he published in 22 parts. Trained und ...

. The 1969

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

volume on bivalves placed ''Praeleda'' as a synonym of the genus '' Deceptrix'', a placement that was not fully accepted by subsequent authors. In 1999 Cope suggested the two genera were distinct, an opinion that has since been accepted. '' Palaeoconcha'' is known from at least four species ranging across Europe, Asia, North America, and South America.The Paleobiology Database ''Palaeoconcha'' entry
accessed 5 February 2012. Both '' Paulinea'' and '' Pensarnia'' were described by Cope in 1997 from fossils found in early

Arenig In geology, the Arenig (or Arenigian) is a time interval during the Ordovician period and also the suite of rocks which were deposited during this interval. History The term was first used by Adam Sedgwick in 1847 with reference to the "Areni ...

sediments of South Wales. The genus '' Similodonta'' is known from several species which range across North America, Asia, and Europe.The Paleobiology Database ''Similodonta'' entry
accessed 5 February 2012. The genus '' Eritropis'' was formerly included in the subfamily, however it was moved to a new family, Eritropidae by John C. Cope in 2000. ''Deceptrix'' was included in Praenuculinae and the genus '' Cardiolaria'' was listed in Praenuculidae, without subfamily placement, by Teresa M. Sánchez in her 1999 description of the Praenuculidae subfamilies. However both ''Deceptrix'' and ''Cardiolaria'' are currently accepted as members of the family Cardiolariidae erected by Cope in 1997.The Paleobiology Database Cardiolariidae entry
accessed 5 February 2012.

Genera

*'' Cuyopsis'' *'' Fidera'' *'' Ledopsis'' *'' Palaeoconcha'' *'' Paulinea'' *'' Pensarnia'' *'' Praeleda'' *'' Praenucula'' (type genus) *'' Trigonoconcha'' *'' Similodonta'' *'' Villicumia''

References

{{Taxonbar, from=Q7237539 Praenuculidae Prehistoric bivalves Ordovician animals Prehistoric animal subfamilies Ordovician first appearances Devonian extinctions