''Leptolepis'' (from el, λεπτός , 'slight' and el, λεπίς 'scale') is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

- teleost fish that lived in what is now Europe during the Jurassic period ( Toarcian– Callovian ages).

Species

The genus ''Leptolepis'' was for a long time used as a wastebasket taxon for various small, unspecialised teleosts that did not form a natural

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. In 1974 the Swedish ichthyologist Orvar Nybelin revised the genus, restricting it to seven species from the Early to Middle Jurassic of Europe. Other species were reassigned to different genera. * ''Leptolepis autissiodorensis'' * ''Leptolepis coryphaenoides'' * ''Leptolepis jaegeri'' * ''Leptolepis nathorsti'' * ''Leptolepis normandica'' * ''Leptolepis saltviciensis'' * ''Leptolepis woodwardi''

Species formerly placed in ''Leptolepis''

* ''Leptolepis talbragarensis'' (Now referred to '' Cavenderichthys'') * ''Leptolepis koonwarri'' (Now referred to '' Waldmanichthys'')Sferco, Emilia, Adriana López-Arbarello, and Ana María Báez. "Phylogenetic relationships of† Luisiella feruglioi (Bordas) and the recognition of a new clade of freshwater teleosts from the Jurassic of Gondwana." BMC Evolutionary Biology 15.1 (2015): 1.

Appearance

Clarkeiteuthis and Leptolepis reconstruction

Length of ''Leptolepis'' was about long, and superficially resembled the unrelated modern

herring Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, i ...

. While more

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

teleosts such as ''

Pholidophorus ''Pholidophorus'' (from el, φολῐ́ς , 'horny scale' and el, φέρω , 'to bear') is an extinct genus of stem-teleost fish. Numerous species were assigned to this genus in the past, but only the type species ''Pholidophorus latiusculus'', ...

'' had skeletons composed of a mixture of bone and

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

, ''Leptolepis'' resembled modern teleosts in possessing a skeleton completely made of bone.The virtual petrified wood museum
/ref> Another modern development in ''Leptolepis'' were its cycloid scales, which lacked the covering of ganoine present in more basal teleosts. These two developments made swimming easier, as the bony

spine Spine or spinal may refer to: Science Biology * Vertebral column, also known as the backbone * Dendritic spine, a small membranous protrusion from a neuron's dendrite * Thorns, spines, and prickles, needle-like structures in plants * Spine (zoolog ...

was now more resistant to the pressure caused by the S movements made while swimming. Mass graves of ''Leptolepis'' have indicated that species probably lived in schools which would provide some protection from predators while the creatures fed on surface plankton. '' Pelagosaurus'' was a known predator of ''Leptolepis'', as a ''Pelagosaurus'' fossil was found with ''Leptolepis'' remains in its stomach. '' Clarkeiteuthis'' is known from three specimens with ''Leptolepis'' in its arms, which estimate that ''Leptolepis'' is probably most common prey of ''Clarkeiteuthis''.

The Morrison cf. ''Leptolepis''

Known only from a single nearly complete skeleton found at Rabbit Valley, Colorado.Foster, J. (2007). "cf. ''Leptolepis''." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. p. 135. A fish that was deeper bodied than its co-occurring contemporaries '' Morrolepis'' and '' Hulettia''. The Morrison cf. ''Leptolepis'' probably had a live mass of about . It is the only teleost fish known from the formation and was morphologically more highly derived than other Morrison fish. A specific example of apomorphy in cf. ''Leptolepis'' is its "more modern tail structure" compared to ''Morrolepis''. It is believed to have fed on fish and small invertebrates.

References

Bibliography

* Silva Santos, R. (1958) - Leptolepis diasii, novo peixe fossil da Serra do Araripe, Brasil”. Boletim da Divisa˜o de Geologia e Mineralogia do Departamento Nacional de Produc¸a˜o Mineral, Notas Preliminares, Brazil 108, 1–15. o, Kiadó: Departamento Nacional de Produc¸a˜o Mineral. * Maisey, J.. Santana fossils, an illustrated atlas. Neptune City, New Jersey, USA: T.F.H. Publications (1991) * Silva Santos, R. (1995) - Santanichthys, novo epı´teto gene´rico para Leptolepis diasii Silva Santos, 1958 (Pisces, Teleostei) da Formac¸a˜o Santana (Aptiano), Bacia do Araripe, NE do Brasil”. Anais da Academia Brasileira de Cieˆncias, Brazil 67, 249–258. o, Kiadó: Academia Brasileira de Cieˆncias. * Filleul, Arnaud, John G. Maisey (2004) - Redescription of Santanichthys diasii (Otophysi, Characiformes) from the Albian of the Santana Formation and Comments on Its Implications for Otophysan Relationships”. ''American Museum Novitates'', New York, NY, USA 3455, American Museum of Natural History {{Taxonbar, from=Q839380 Prehistoric teleostei Prehistoric ray-finned fish genera Toarcian genus first appearances Bathonian genera Callovian genus extinctions Jurassic bony fish Jurassic fish of Europe Jurassic England Jurassic France Jurassic Germany Jurassic Italy Jurassic Norway Fossils of England Fossils of France Fossils of Germany Fossils of Italy Fossils of Norway Fossil taxa described in 1843 Taxa named by Louis Agassiz