# Pinna (bivalve)

Pinna is a genus of bivalve molluscs belonging to the family Pinnidae. The type species of the genus is Pinna rudis.
The most extensively studied species in the genus is P. nobilis, a Mediterranean pen shell which was historically important as the principal source of sea silk.

## Description

These pen shells can reach a length of about 80–90 cm (31–35 in). They are characterized by thin, elongated, wedge-shaped, and almost triangular shells with long, toothless edges. The surface of the shells shows radial ribs over their entire length.
Pinna is distinguished from its sibling genus Atrina by the presence of a sulcus dividing the nacreous region of the valves, and the positioning of the adductor scar on the dorsal side of shells.
These bivalves most commonly lie point-first on the sea bottom in which they live, anchored by a net of byssus threads.

## Distribution

Species in the genus Pinna are geographically widespread. This genus is very ancient, going back up to the Carboniferous period. It is especially represented in Jurassic and Cretaceous fossils.

## Species

According to the World Register of Marine Species, extant species in the genus Pinna are:
* Pinna angustana Lamarck, 1819
* Pinna atropurpurea G. B. Sowerby I, 1825
* Pinna attenuata Reeve, 1858
* Pinna bichi Thach, 2016
* Pinna bicolor Gmelin, 1791
* Pinna carnea Gmelin, 1791
* Pinna cellophana Matsukuma & Okutani, 1986
* Pinna deltodes Menke, 1843
* Pinna dolabrata Lamarck, 1819
* Pinna electrina Reeve, 1858
* Pinna epica Jousseaume, 1894
* Pinna evexa Callomon, 2023
* Pinna exquisita Dall, Bartsch & Rehder, 1938
* Pinna fimbriatula Reeve, 1859
* Pinna incurva Gmelin, 1791
* Pinna linguafelis (Habe, 1953)
* Pinna madida Reeve, 1858
* Pinna menkei Reeve, 1858
* Pinna muricata Linnaeus, 1758
* Pinna nembia Simone, 2024
* Pinna nobilis Linnaeus, 1758
* Pinna papyracea Gmelin, 1791
* Pinna pereria Simone, 2024
* Pinna rapanui Araya & Osorio, 2016
* Pinna rudis Linnaeus, 1758
* Pinna rugosa G. B. Sowerby I, 1835
* Pinna saccata Linnaeus, 1758
* Pinna sanguinolenta Reeve, 1858
* Pinna trigonalis Pease, 1861
* Pinna trigonium Dunker, 1852
* Pinna trindadis Simone, 2024
* Pinna wayae P. W. Schultz & M. Huber, 2013
The following species are only known from the fossil record:
* †Pinna anderssoni Wilckens, 1910
* †Pinna arcuata J. Sowerby, 1821
* †Pinna blanfordi O. Boettger, 1880
* †Pinna cretacea (Schlotheim, 1813)
* †Pinna dissimilicostata X.-M. Gan, 1978
* †Pinna distans F. W. Hutton, 1873
* †Pinna folium G. Young & Bird, 1822
* †Pinna fragilis Watelet, 1868
* †Pinna freneixae Zinsmeister & Macellari, 1988
* †Pinna huiyangensis R.-J. Zhang, 1977
* †Pinna karabiensis Yanin, 2021
* †Pinna kawhiana Marwick, 1953
* †Pinna keexwaanensis McRoberts, 2017
* †Pinna lanceolata J. Sowerby, 1821
* †Pinna margaritacea Lamarck, 1805
* †Pinna mitis J. Phillips, 1829
* †Pinna muikadanensis Nakazawa, 1961
* †Pinna nyainrongensis S.-X. Wen, 1979
* †Pinna octavia Marwick, 1953
* †Pinna pacata Shilekhin, Mazaev & Biakov, 2023
* †Pinna plicata F. W. Hutton, 1873
* †Pinna qinghaiensis Y.-J. Lu, 1986
* †Pinna rembangensis K. Martin, 1910
* †Pinna robinaldina A. d'Orbigny, 1844
* †Pinna sobrali Zinsmeister, 1984
* †Pinna socialis A. d'Orbigny, 1850
* †Pinna subcuneata Eichwald, 1865
* †Pinna suprajurensis A. d'Orbigny, 1850
* †Pinna torulosa Repin, 2001
* †Pinna vanhoepeni Rennie, 1930
* †Pinnacaris dentata Garassino & Teruzzi, 1993
* †Pinnatiporidium toomeyi (Dragastan) Dragastan & Schlagintweit, 2005
* †Pinnatoporella carinata (Etheridge, 1879)
* †Pinnatulites microrugosa Hessland, 1949
* †Pinnatulites tumida Hessland, 1949
* †Pinnatulites varia Sarv, 1959

## Nomen nudum

* Pinna inflata Röding, 1798
* Pinna lubrica Lightfoot, 1786
* Pinna nebulosa Lightfoot, 1786
* Pinna nigricans Lightfoot, 1786
* Pinna striata Röding, 1798
* Pinna tenera Lightfoot, 1786
* Pinna violacea Röding, 1798

## Nomen dubium

* Pinna atrata Clessin, 1891
* Pinna bullata Gmelin, 1791
* Pinna marginata Lamarck, 1819
* Pinna minax Hanley, 1858
* Pinna rollei Clessin, 1891
* Pinna rostellum Hanley, 1858
* Pinna rotundata Linnaeus, 1758
* Pinna sanguinea Gmelin, 1791
* Pinna virgata Menke, 1843

## Synonyms

* Pinna squamosissima Philippi, 1849: synonym of Atrina serrata (G. B. Sowerby I, 1825)
* Pinna strangei Reeve, 1858: synonym of Atrina strangei (Reeve, 1858)
* Pinna stutchburii Reeve, 1859: synonym of Pinna attenuata Reeve, 1858
* Pinna subviridis Reeve, 1858: synonym of Atrina seminuda (Lamarck, 1819)
* Pinna tasmanica Tenison-Woods, 1876: synonym of Atrina tasmanica (Tenison Woods, 1876)
* Pinna truncata Philippi, 1844: synonym of Atrina fragilis (Pennant, 1777)
* Pinna tuberculosa Sowerby, 1835: synonym of Atrina tuberculosa (G. B. Sowerby I, 1835)
* Pinna varicosa Lamarck, 1819: synonym of Pinna carnea Gmelin, 1791
* Pinna vespertina Reeve, 1858: synonym of Pinna atropurpurea G. B. Sowerby I, 1825
* Pinna vexillum Born, 1778: synonym of Atrina vexillum (Born, 1778)
* Pinna vitrea Gmelin, 1791: synonym of Streptopinna saccata (Linnaeus, 1758)
* Pinna vulgaris Roissy, 1804: synonym of Pinna nobilis Linnaeus, 1758
* Pinna whitechurchi Turton, 1932: synonym of Atrina squamifera (G. B. Sowerby I, 1835)
* Pinna zebuensis Reeve, 1858: synonym of Pinna muricata Linnaeus, 1758
* Pinna zelandica Gray, 1835: synonym of Atrina zelandica (Gray, 1835)
* Pinna angustana
* Pinna atropurpurea
* Pinna attenuata
* Pinna bicolor
* Pinna carnea
* Pinna deltodes
* Pinna electrina
* Pinna incurva
* Pinna muricata
* Pinna nobilis
* Pinna rudis
* Pinna rugosa
* Pinna trigonium