''Exellia'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...
of extinct
spadefish
Ephippidae is a family containing the spadefishes, with about eight genera and a total of 20 marine species. Well-known species include the Atlantic spadefish (''Chaetodipterus faber'') and the reef-dwelling genus ''Platax'', the batfishes, whic ...
that lived in the
Tethys Ocean
The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents ...
during the early
Paleogene
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of ...
. The adult form is shaped akin to a large spadefish or a short
dolphinfish, with very large
pelvic fin
Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods.
Structure and function Structure
In actinopterygians, the pelvic fin consists of two e ...
s, and a long dorsal fin starting from in front of the eyes to near the base of the
caudal peduncle
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...
. The juvenile form resembles a juvenile
drumfish, with the dorsal fin forming a long crest on top of the head.
The earlier species, ''E. proxima'', is known from the
Danata Formation Lagerstätten from the
Late Paleocene
The Thanetian is, in the ICS Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene Epoch or Series. It spans the time between . The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age (part ...
of
Turkmenistan
Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the s ...
. The latter-occurring species, ''E. velifer'', is the better studied species, and is known from numerous adult and juvenile specimens from the Middle Eocene
Monte Bolca Lagerstätten.
Most researchers regard ''Exellia'' as a spadefish, though, some remove this genus, and the related ''
Eoluvarus''
to a separate
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
, "Exelliidae."
References
Exelliids
Prehistoric ray-finned fish genera
{{Ephippidae-stub