''Polymerichthys nagurai'' is an extinct, superficially eel-like
alepisauroid from the Middle Miocene of Japan. The holotype specimen, no. 6599, was originally collected by Masayasu Nagura, a
suzuri maker, around 1927. The specimen demonstrates several features typical of other
families
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 ...
of Alepisauroidei, including head anatomy very similar to the daggertooths of
Anotopteridae
The daggertooths (genus ''Anotopterus'') are a genus of marine mesopelagic fish in the order Aulopiformes, the sole genus of the family Anotopteridae. They are found in oceans worldwide, but prefer cooler waters.
Description
Daggertooths are not ...
, and a well-developed dorsal fin similar to that of the
lancetfish
Lancetfishes are large oceanic predatory fishes in the genus ''Alepisaurus'' ("scaleless lizard") in the monogeneric family Alepisauridae.
Lancetfishes grow up to in length. Very little is known about their biology, though they are widely di ...
of Alepisauridae.
Etymology
The generic name literally translates as "many
meristic Meristics is an area of ichthyology and herpetology which relates to counting quantitative features of fish and reptiles, such as the number of fins or scales. A meristic (countable trait) can be used to describe a particular species of fish, or us ...
fish," in reference to how the fish has numerous meristics units, including how the dorsal fin, which runs down the length of the body starting from behind the head, has somewhere between 300 and 350 rays, and how it has at least 186
vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...
e. The specific name honors the holotype's discoverer, Yuzo Nagura.
See also
Other notable extinct Cenozoic aulopiforms include:
*''
Argillichthys
''Argillichthys toombsi'' is an extinct lizardfish from the Ypresian-aged London Clay Formation from Lower Eocene England. It is known from a skull.
See also
Other notable extinct Cenozoic aulopiforms include:
*''Alepisaurus paronai'', an ex ...
'', a synodontid
lizardfish
The Synodontidae or lizardfishes(or typical lizardfish to distinguish them from the Bathysauridae and Pseudotrichonotidae) are benthic (bottom-dwelling) marine and estuarine bony fishes that belong to the aulopiform fish order, a diverse grou ...
from the
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian i ...
London Clay
The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 56–49 million years ago) age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from t ...
*''
Alepisaurus paronai
''Alepisaurus paronai'' is an extinct species of lancetfish known from a fossil skull found in Middle Miocene-aged strata in Piedmont, Italy. The skull is very similar in anatomy and dimensions to that of the extant long-snouted lancetfish. The ...
'', an extinct
lancetfish
Lancetfishes are large oceanic predatory fishes in the genus ''Alepisaurus'' ("scaleless lizard") in the monogeneric family Alepisauridae.
Lancetfishes grow up to in length. Very little is known about their biology, though they are widely di ...
that lived in middle
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...
Piemonte
it, Piemontese
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References
Prehistoric aulopiformes
Miocene fish of Asia
{{Alepisauriformes-stub