Zeiformes

(vertebrate zoology) The dories, a small order of teleost fishes, distinguished by the absence of an orbitosphenoid bone, a spinous dorsal fin, and a pelvic fin with a spine and five to nine soft rays.

(Dories)

Class: Actinopterygii

Order: Zeiformes

Number of families: 6

Evolution and systematics

Fossils identified as zeiform fishes are confined to marine habitats and are relatively young, ranging in age from Oligocene to Holocene deposits. They have been found in Europe, the West Indies, South Africa, and Indonesia. The phylogenetic relationships of the Zeiformes were explicated by Johnson and Patterson in their 1993 publication on the phylogenetic relationships of the percomorph fishes. They recognized Zeiformes as a monophyletic taxon characterized by the following shared derived characters. There is a distinctive configuration of upright columnar processes on the dorsal elements of the gill arch skeleton. Baudelot's ligament originates immediately under the vagus foramen of the exoccipitals. The distal part of the proximal middle radials of the dorsal fin pterygiophores is expanded laterally. The palatines have a specialized, mobile articulation with the ectopterygoid, which is truncated dorsally. The metapterygoid is extremely reduced, and a continuous median cartilage extends below the frontals and between the ethmoid cartilage and pterosphenoids.

Based on what they term "admittedly tenuous evidence," Johnson and Patterson considered the Zeiformes to be the sister taxon of a group making up the order Beryciformes and a huge conglomeration of spiny-rayed fishes known as the "percomorpha," including the Perciformes, Pleuronectiformes (flounders, soles, etc.), Tetraodontiformes (triggerfishes and pufferfishes, among others), Scorpaeniformes (scorpionfishes, gurnards, flatheads, and so on), Dactylopteriformes (helmet gurnards), Synbranchiformes (swamp eels, spiny eels, and others), Elassomatidae (pygmy sunfish), Gasterosteriformes (pipefish, trumpetfish, etc.), Mugiloidei (mullets), and Atherinomorpha (Atheriniformes, Beloniformes, and Cyprinodontiformes).

The order Zeiformes comprises six families: Zeidae, Parazenidae, Zeniontidae, Oreosomatidae, Grammicolepidae, and Caproidae. In their 1966 seminal paper on the phylogenetic relationships of teleost fishes, P. H. Greenwood and collaborators included the boarfishes (family Caproidae) in the Zeiformes, but they presented no evidence to support this assignment. Heemstra excluded the Caproidae from the Zeiformes in his 1980 taxonomic revision of the zeid fishes of South Africa, and in the book Smiths' Sea Fishes, Heemstra included the Caproidae in the order Perciformes. For the purposes of this publication, the Caproidae are included in the Zeiformes.

Much work remains to be done on the systematics of the Zeiformes, and the classification adopted here is tentative. The composition, definitions, and distinction of the families Zeidae, Zeniontidae, and Parazenidae are unsettled. The genus Cyttomimus (Gilbert, 1905) appears to be related closely to Capromimus (Gill, 1893). Although these two genera seem to be placed correctly in the Zeiformes, their affinity with any of the families recognized here is unclear. The genus Macrurocyttus (Fowler, 1933) may belong in the Zeniontidae, but the head of Macrurocyttus acanthopodus (Fowler, 1933) looks very different from those of the two species of Zenion that are known.

Physical characteristics

The body is deep, compressed, and oblong to disk-shaped. The upper jaw is more or less protrusible, and there are minute, slender, conical teeth in the jaws and vomer. Adults range in size from the dwarf dory (Zenion hololepis) at 4 in (10 cm) to the 3-ft (90 cm), 12-lb (5.3 kg) South African Cape dory (Zeus capensis). Most species are silvery, bronzy, brown, or reddish. The John Dory is silvery or bronzy, with indistinct longitudinal dark stripes from head to tail and a conspicuous white or yellow-edged black ocellus in the middle of the body. The juvenile buckler dory (Zenopsis conchifer) is silvery and covered with scattered, vaguely defined black spots. Dories can change from silvery to dark brown or gray in seconds. Males and females are colored similarly.

Zeiform fishes can be recognized by the following combination of characters: five to ten dorsal fin spines; zero to four anal fin spines; pelvic fins with one spine and five to seven soft rays or no spine and six to 10 soft rays; a caudal fin with 11, 13, or 15 principal (segmented) rays, of which 9, 11, or 13 rays are branched; and unbranched dorsal, anal, and pectoral fin rays. The orbitosphenoid bone is absent, and there is no subocular shelf or supramaxilla. There are seven or eight branchiostegal rays, 3.5 gills (no slit behind the last hemibranch), 25–46 vertebrae, and a gas bladder.

Distribution

The order is represented in the western Atlantic from Canada to Argentina, including the Gulf of Mexico and the Caribbean Sea. In the eastern Atlantic, zeiforms are known from the North Sea to South Africa, including the Mediterranean, Black Sea, Azores, Madeira, Canary Islands, Cape Verde Islands, and Saint Helena. In the Indian Ocean, zeiforms occur along the east coast of Africa to the Gulf of Aden, Oman, the Persian Gulf, Pakistan, India, Sri Lanka, Maldives, and Madagascar and eastward to the Andaman Sea, Burma, Thailand, Cambodia, Indonesia, Vietnam, Australia, New Zealand, New Guinea, the Philippines, China, Taiwan, Japan, and Korea. In the eastern Pacific, zeiforms range from Canada to Chile.

Habitat

Most zeiform fishes are demersal, living near the bottom of the continental shelf or upper continental slope region. They range in depth from 110 to 5,084 ft (35–1,550 m). The adult John dory (Zeus faber), and probably adults of some other zeiform species, frequently occurs in midwater or near the surface. Some species have a pelagic prejuvenile stage that lives near the surface in the open ocean. Adults are found over soft (sandy or muddy) or hard (rocky) substrata.

Behavior

Little is known of the behavior of zeiforms, as they live at depths where they are difficult to observe. Adults of the John dory (Z. faber) are mainly solitary. The buckler dory (Z. conchifer) often occurs in small aggregations.

Feeding ecology and diet

Zeiform fishes are carnivores; they feed mainly on a variety of fishes but also consume cephalopods and crustaceans. Juveniles of the larger species and adults of the dwarf dories (family Zeniontidae) and tinselfishes (family Grammicolepidae) feed on zooplankton (e.g., copepods, pteropods, fish and crustacean larvae). Adults of the larger zeiform fishes (John dory and the buckler dory) are eaten only by large piscivorous predators (e.g., some sharks, goosefishes [Lophus species], and lancetfishes [Alepisaurus species]). Juveniles and adults of small zeiforms (e.g., Zenion species) are subject to predation by a variety of piscivores.

Reproductive biology

The sexes are separate. Females grow larger than males. Spawning has not been observed, but zeiforms apparently are "broadcast spawners," with the eggs and sperm released into the water column and fertilization taking place in the sea. The eggs and larvae are pelagic and float near the surface; the eggs are spherical, 0.04–0.1 in (1–2.8 mm) in diameter, with a single oil globule. There are no reports of nests or egg guarding or parental care in zeiform fishes.

Conservation status

None of the zeiform fishes are listed by the IUCN. Some populations probably are overexploited in areas where intensive trawling takes place.

Significance to humans

The larger species of zeiforms are of some commercial importance as food fishes. Most zeiforms are caught by trawlers, but anglers also catch a few of the larger species.

Species accounts

Resources

Karrer, C., and P. C. Heemstra. "Family No. 140: Grammicolepididae." In Smiths' Sea Fishes, edited by M. M. Smith and P. C. Heemstra. Johannesburg: Macmillan South Africa, 1986.

Nelson, J. S. Fishes of the World. 3rd edition. New York: John Wiley & Sons. 1994.

Smith, M. M., and P. C. Heemstra, eds. Smiths' Sea Fishes. Johannesburg: Macmillan South Africa. 1986.

Barnard, H. K. "A Monograph of the Marine Fishes of South Africa. Part 1." Annals of the South African Museum 21(1925): 1–105.

Bigelow, H. B., and W. C. Schroeder. "Fishes of the Gulf of Maine." U.S. Fish and Wildlife Service Fishery Bulletin 53(1953): 1–577.

Dunn, M. R. "The Biology and Exploitation of John Dory, Zeus faber (Linnaeus, 1758), in Waters of England and Wales." ICES Journal of Marine Science 58, no. 1 (2001): 96–105.

Fowler, H. W. "The Buckler Dory and Descriptions of Three New Fishes from off New Jersey and Florida." Proceedings of the Academy of Natural Sciences of Philadelphia 86 (1934): 353–361.

Greenwood, P. H., D. E. Rosen, S. H. Weitzman, and G. S. Myers. "Phyletic Studies of Teleostean Fishes, with a Provisional Classification of Living Forms." Bulletin of the American Museum of Natural History 131, no. 4 (1966): 339–455.

Heemstra, P. C. "A Revision of the Zeid Fishes (Zeiformes: Zeidae) of South Africa." Ichthyology Bulletin of the J. L. B. Smith Institute of Ichthyology 41 (1980): 1–18.

Parin, N., and O. D. Borodulina. "Preliminary Review of the Bathypelagic Fish Genus Antigonia Lowe (Zeiformes, Caproidae)." Transactions of the P. P. Shirsov Institute of Oceanology 121 (1986): 1–105, 141–172.

Yoneda, M., S. Yamasaki, K. Yamamoto, H. Horikawa, and M. Matsuyama. "Age and Growth of John Dory, Zeus faber (Linnaeus, 1758), in the East China Sea." ICES Journal of Marine Science 59, no. 4 (2002): 749–756.

[Article by: Phillip C. Heemstra, PhD]

A small order of teleost fishes, structurally intermediate between the Beryciformes and the Perciformes. This group is also known as the Zeomorphi or Zeoidea; commonly the fish are known as dories. There is no orbitosphenoid bone; the pelvic fin has a spine and from five to nine soft rays; and there is a more or less distinct anterior, spinous anal fin of one to four spines, as well as a spinous dorsal fin (see illustration). The zeiform fishes, which are known from the Paleocene on, are grouped into 6 families, perhaps 12 genera, and fewer than 50 species. All are marine, living in shore waters and chiefly at moderate depths off tropical and temperate coasts. Most are of small size and of minor economic importance. See also Actinopterygii; Beryciformes; Perciformes.

John dory (Zenopsis ocellata). (After G. B. Goode, Fishery Industries of the United States, sect. 1, 1884)

Zeiformes Fossil range: Late Cretaceous–Recent PreЄ Є O S D C P T J K Pg N [1]
Mirror dory, family Zeidae
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Zeiformes
Families
Suborder Zeioidei Family Cyttidae Family Grammicolepididae Family Oreosomatidae (oreos) Family Parazenidae (parazen and allies) Family Zeidae (true dories) Family Zenionidae (Macrurocyttidae) Suborder Caproidei Family Caproidae (boarfishes)

The Zeiformes are a small order of marine ray-finned fishes most notable for the dories, a group of common food fish. The order consists of about 40 species in seven families, mostly deep-sea types.

Zeiform bodies are usually thin and deep. Mouths are large, with distensible jaws, and there is no orbitosphenoid]. Pelvic fins have 5-10 soft rays and possibly a spine, 5-10 dorsal fin spines and up to 4 anal fin spines. They range in size from Macrurocyttus acanthopodus, at 43 millimetres (1.7 in) in length, to the Cape dory, which measures up to 90 centimetres (35 in).^[1]

The classification of the boarfishes (Caproidae) in this order is uncertain, since they have many perciform characters, for instance in the caudal skeleton.

References

1. ^ ^{a b} Karrer, C. & John, H-C. (1998). Paxton, J.R. & Eschmeyer, W.N.. ed. Encyclopedia of Fishes. San Diego: Academic Press. pp. 165–167. ISBN 0-12-547665-5. 

• "Zeiformes". FishBase. Ed. Ranier Froese and Daniel Pauly. March 2005 version. N.p.: FishBase, 2005.
• J.S. Nelson, Fishes of the World

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