The Zeiformes are a small

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

of exclusively marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

es most notable for the dories, a group of common

food fish Many species of fish are caught by humans and consumed as food in virtually all regions around the world. Their meat has been an important dietary source of protein and other nutrients in the human diet. The English language does not have a s ...

. The order consists of about 33 species in six extant families, mostly deep-sea types. The boarfishes (

Caproidae Caproidae, or boarfishes, are a small family of marine fishes comprising two genera and 19 species. These fishes are found throughout the world in temperate and tropical seas. Taxonomy Caproidae was first proposed as a family in 1835 by the F ...

) have been previously included in this order though they are currently included in the

Perciformes Perciformes (), also called the Acanthopteri, is an order or superorder of ray-finned fish in the clade Percomorpha. ''Perciformes'' means " perch-like". Among the well-known members of this group are perches and darters ( Percidae), and als ...

. Zeiform bodies are usually thin and deep. Mouths are large, with distensible jaws, and there is no orbitosphenoid.

Pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s have 5–10 soft rays and possibly a spine, 5–10

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

spines and up to 4

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 ...

spines. They range in size from the dwarf dory ''(Macrurocyttus acanthopodus)'', at in length, to the Cape dory ''(Zeus capensis)'', which measures up to . The earliest known member of the order is '' Cretazeus'' from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

(late

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

or early

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

) of

Nardò Nardò ( or ; ) is a town and ''comune'' in the southern Italian region of Apulia, in the Province of Lecce. Lies on a lowland area placed at south-west of its Province, its border includes part of the Ionian coast of Salento. For centuries, i ...

, Italy. Uniquely, despite its age, ''Cretazeus'' is thought to be a derived

crown-group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

zeiform closely related to the

Parazenidae Parazenidae is a family of zeiform fishes found in the Atlantic and Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to th ...

(in contrast, the two most basal zeiform families are known from later, during the early

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

). This suggests that at least six lineages of zeiforms were present during the Late Cretaceous and survived the Cretaceous-Paleogene extinction, despite this not being preserved in the fossil record. Aside from ''Cretazeus'', an earlier record of the zeiforms is an indeterminate fossil

otolith An otolith (, ' ear + , ', a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle (ear), utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule ...

("genus Zeiformomum" ''tyleri'') from the

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

of Spain, but its specific affinities remain uncertain. A potentially older genus, '' Palaeocyttus'' of Portugal, is known only from a poorly-preserved specimen and may not be a zeiform.

Families

*Family Cyttidae (lookdown dories) *Family

Grammicolepididae The Grammicolepididae are a small family of deep-sea ray-finned fishes in the order Zeiformes. They are called tinselfishes due to their silvery color. They are found near the bottom on the continental slope in the tropical and temperate regions ...

(tinselfishes) *Family Oreosomatidae (oreos) *Family

(parazens) *Family Zeidae (dories) *Family Zenionidae (zeniontids) (formerly known as Macrurocyttidae) *Family † Archaeozeidae (extinct, ''Archaeozeus skamolensis'') *Family † Bajaichthyidae (extinct, ''Bajaichthys elegans'') *Family † Cretazeidae (extinct, ''Cretazeus rinaldii''; alternatively a member of Parazenidae) *Family † Protozeidae (extinct, ''Protozeus kuehnei'') *Family †

Sorbinipercidae Sorbinipercidae is an extinct family of zeiid fish from the Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Peri ...

(extinct)

References

* * J.S. Nelson, ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

'' * {{Authority control Ray-finned fish orders Extant Santonian first appearances Taxa named by Charles Tate Regan