''Eobothus'' ('dawn ''

Bothus ''Bothus'' is a genus of flatfish in the family Bothidae (lefteye flounders) from the Pacific, Indian and Atlantic Oceans. Some species in this genus have spots consisting of blue rings. Species There are currently 17 recognized species in this ...

) is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of very small, fossil marine

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish Order (biology), suborder Pleuronectoidei, also called the Heterosomata. In many species, both eyes lie on one side of the head, one or the other migrating through or around ...

known from the Eocene. It is one of the oldest flatfish known from fossil remains. It contains a single definitive species, ''E. minimus'' (

Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

, 1839) from the

Early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

-aged

Monte Bolca Monte Bolca is an Ypresian, Early Eocene-aged geologic site located near Verona, Italy, Verona, Italy. A ''Konservat-Lagerstätte'', it contains an extremely well-preserved and diverse marine biota, including the most diverse fish fauna of any Ce ...

site of Italy. This species was initially erroneously described by Volta (1796) as a fossil specimen of the

European plaice The European plaice (''Pleuronectes platessa''), commonly referred to as simply plaice, is a species of marine flatfish in the genus Pleuronectes of the family Pleuronectidae. Description The European plaice is characterized, on their dorsal ...

(synonym ''Pleuronectes quadratulus''), and later officially described as ''

Rhombus In plane Euclidean geometry, a rhombus (: rhombi or rhombuses) is a quadrilateral whose four sides all have the same length. Another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length. The rhom ...

minimus'' by

in 1839. It was moved to its own genus, ''Eobothus'', in 1914. In addition, two dubious fossil genera are also known: ''E. singhi'' Sahni & Choudhary, 1971 from the early Eocene of

Rajasthan, India Rajasthan (; lit. 'Land of Kings') is a state in northwestern India. It covers or 10.4 per cent of India's total geographical area. It is the largest Indian state by area and the seventh largest by population. It is on India's northweste ...

( Kapurdi Formation)Sahni A & Choudhary N.K. (1971)
"Lower Eocene Fishes from Barmer, South Western Rajasthan"
''Proc. Indian Natl. Sci. Acad.'' 38(A): p. 97-102 and ''E. vialovi''

Berg Berg may refer to: People *Berg (surname), a surname (including a list of people with the name) * General Berg (disambiguation) * Berg Ng (born 1960), Hong Kong actor * Berg (footballer, born 1963), Ninimbergue dos Santos Guerra, Brazilian footba ...

, 1941 from the

Middle Eocene The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') a ...

Uzbekistan , image_flag = Flag of Uzbekistan.svg , image_coat = Emblem of Uzbekistan.svg , symbol_type = Emblem of Uzbekistan, Emblem , national_anthem = "State Anthem of Uzbekistan, State Anthem of the Republ ...

. However, these species may not belong to this genus, or even be flatfish at all. ''Eobothus'' is significant as one of the earliest genera of flatfish, one of the last major fish groups to evolve. It closely resembled modern flatfish, with an oval-shaped body about long, surrounded by elongated

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

and

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

s. In the adult, the eyes were both located on the left side of the head, as in modern species, and the fish would have lain flat against the seafloor on its right side. This was an evolutionary advance from the more primitive Eocene flatfishes '' Heteronectes'' and '' Amphistium'', in which the eyes only partially migrated. It is sometimes placed in the

Bothidae Bothidae or lefteye flounders are a family of flounders. They are called "lefteye flounders" because most species lie on the sea bottom on their right sides, with both eyes on their left sides. The family is also distinguished by the presence of ...

, as its name suggests, but more recent studies have found such a classification to be inconclusive, and it is thus now placed as an indeterminate flatfish. Some studies have found it to be a basal member of the superfamily Pleuronectoidea.

References

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species or languages). It is one of the mo ...

Prehistoric percomorph genera {{Pleuronectiformes-stub Ypresian genera Eocene fish of Europe Fossils of Italy Fossil taxa described in 1914