Leptaena
Leptaena is an extinct genus of mid-sized brachiopod that existed from the Dariwilian epoch to the Emsian epoch,[1][2] though some specimens have been found in strata as late in age as the Tournasian epoch.[1][3] Like some other Strophomenids, Lepteana were epifaunal, meaning they lived on top of the seafloor, not buried within it, and were suspension feeders.[4]
| Leptaena Temporal range:   | |
|---|---|
![]()  | |
| Leptaena rhomboidalis | |
| Scientific classification  | |
| Domain: | Eukaryota | 
| Kingdom: | Animalia | 
| Phylum: | Brachiopoda | 
| Class: | †Strophomenata | 
| Order: | †Strophomenida | 
| Family: | †Rafinesquinidae | 
| Subfamily: | †Leptaeninae | 
| Genus: | †Leptaena Dalman, 1828  | 
| Type species | |
| Leptaena rugosa Dalman, 1828  | |
| Species | |
| 
 See Species  | |
| Synonyms | |
  | |
Physical description
    
Leptaena usually have concentric wrinkling and concentric lines on the shell. Leptaena have a concavo-convex profile, and are sometimes Semiquadrate to semielliptical. The Cardinal Process is split in two and the hinge line is straight.[4] Their width is usually greater than their length, like most Strophomenids.
Distribution
    
Leptaena fossils have been found on every continent except Antarctica.[3][5][6]
Species
    
Leptaena was a diverse genus, with over 70 recognized species and subgenera. Species in the genus Leptaena include the following.[3][6][7] Any synonymous genera to which a given species may belong to are labelled with the synonymous genus in parentheses.
- L. acuta (Kurnamena) (Roomusoks, 2004)
 - L. acuticuspidata Amsden, 1958
 - L. aequalis Amsden, 1974
 - L. alliku (Oraspold, 1956)
 - L. altera Rybnikova, 1966
 - L. amelia (Havlicek, 1967)
 - L. analogaeformis Biernat, 1966
 - L. arberae Kelly, 1967
 - L. argentina (Thomas, 1905)
 - L. bergstroemi Cocks, 2005
 - L. borghiana Mergl & Massa, 1992
 - L. boyaca Caster, 1939
 - L. contermina Cocks, 1968
 - L. convexa Weller, 1914
 - L. cooperi Easton et al., 1958
 - L. crassorugata (Similoleptaena) (Rõõmusoks, 2004)
 - L. croma (Havlicek & Storch, 1990)
 - L.crypta Opik, 1930
 - L. cryptoides (Oraspold, 1956)
 - L. dejecta (Baarli, 1995)
 - L. delicata Amsden, 1949
 - L. depressa (Sowerby, 1825)
 - L. diademata (Williams, 1962)
 - L. electra (Havlicek, 1967)
 - L. ennessbe Spjeldnaes, 1957
 - L. enucleata Klenina, 1984
 - L. friedrichi (Similoleptaena) (Rõõmusoks, 2004)
 - L. gibbosa (James, 1874)
 - L. haverfordensis Bancroft, 1949
 - L. holcrofti Bassett, 1974
 - L. indigena Spjeldnaes, 1957
 - L. infrunita (Williams, 1962)
 - L. ingrica (Similoleptaena) (Rõõmusoks, 2004)
 - L. juvenilis (Öpik, 1930)
 - L. kentuckiana Pope, 1982
 - L. lappa (Havlicek & Storch, 1990)
 - L. lappina (Havlicek & Storch, 1990)
 - L. laterorugata (Kurnamena) (Roomusoks, 1989)
 - L. lemniscata (Havlicek, 1967)
 - L. limbifera (Havlicek, 1967)
 - L. martinensis Cocks, 1968
 - L. moniquensis Foerste, 1924
 - L. nanaformis Zhang et al., 1983
 - L. nassichuki Smith, 1980
 - L. odeon Havlicek, 1967
 - L. oklahomensis Amsden, 1951
 - L. ordovicica (Cooper, 1956)
 - L. orhor (Havlicek & Storch, 1990)
 - L. palmrei (Kurnamena) (Roomusoks, 2004)
 - L. parvirugata Hoel, 2005
 - L. parvissima Ivanovskii & Kulkov, 1974
 - L. paucirugata (Roomusoks 1989)
 - L. pertenuis (Similoleptaena) (Rõõmusoks, 2004)
 - L. planitia (Similoleptaena) (Rõõmusoks, 2004)
 - L. poulseni Kelly, 1967
 - L. praequalis Rozman, 1977
 - L. provellerosa (Havlicek & Storch, 1990)
 - L. purpurea Cocks, 1968
 - L. quadrata Bancroft, 1949
 - L. quadrilatera (Logan, 1863)
 - L. rara (Alekseeva and Erlanger, 1983)
 - L. reedi Cocks, 1968
 - L. rhomboidalis (Wahlanberg, 1818)
 - L. richmondensis Foerste, 1909
 - L. roomusoki Cocks, 2005
 - L. rugata (Lindström, 1861)
 - L. rugaurita (Havlicek, 1967)
 - L. rugosa (Dalman, 1828)
 - L. rugosides Oraspold, 1956
 - L. salopiensis (Williams, 1963)
 - L. semiradiata Sowerby, 1842
 - L. senecta Roomusoks, 2004
 - L. sperion Bassett, 1977
 - L. spumiferra (Kurnamea) (Opik, 1930)
 - L. strandi (Spjeldnaes, 1957)
 - L. tarwanpensis (Similoleptaena) (Rõõmusoks, 2004)
 - L. taxilla (Kurnamena) (Oraspold, 1965)
 - L. tenuissimestriata McCoy, 1852
 - L. tenuistrata Sowerby, 1839
 - L. tenuistriata (de Sowerby and Murchison, 1839)
 - L. trifidium (Leptaenopoma) (Marek and Havlíček, 1967)
 - L. trifidum (Marek and Havlíček, 1967)
 - L. undosa (Similoleptaena) (Rõõmusoks, 2004)
 - L. valentia (Cocks, 1968)
 - L. valida Bancroft, 1949
 - L. veldrensis Spjeldnaes, 1957
 - L. vellerosa Havlicek, 1967
 - L. ventricosa Williams, 1963
 - L. zeta Lamont, 1947
 - L. ziegleri Cocks, 1968
 
References
    
- Plaza-Torres, Stephanie; Darroch, Simon; Wagner, Peter. "Family tree of a mass extinction survivor: Phylogenetic analysis of the brachiopod genus Leptaena" (PDF). Smithsonian. Retrieved 31 March 2020.
 - Hoel, Ole (21 January 2014). "Palaeobiology of Silurian Leptaeninae (Brachiopoda) from Gotland, Sweden". Paleontology Journal. 2014: 1–14. doi:10.1155/2014/716053.
 - Paleobiology Database
 - Stigall, Alycia (3 December 2013). "Leptaena". Atlas of Ordovician Life. National Science Foundation. Retrieved 26 March 2020.
 - Global Biodiversity Information Facility
 - Fossilworks
 - Catalog of Life
 
