Basisphenoid absent; orbitosphenoid present, except in gonorynchiforms; mesocoracoid usually present; dermopalatine absent; postcleithrum absent in gonorynchiforms and siluriforms, one in most cypriniforms, and three in some characiforms and gymnotiforms; swim bladder present (except in Gonorynchus) and usually divided into a smaller anterior chamber, which is partially or completely covered by a silvery peritoneal tunic and a larger posterior chamber (reduced or absent in some groups); minute, unicellular, horny projections, termed "unculi," commonly present on various body parts (e.g., mouth region or ventral surface of paired fins), known only from ostar-iophysans; multicellular horny tubercles (= breeding or nuptial tubercles or pearl organs) with keratinous cap well developed; upper jaw protractile in many species; pelvic fins, if present, abdominal. An extensive survey of the subterranean species (hypogean) is given by Proudlove (2005).
Fishes of this group possess a fright reaction elicited by an alarm substance. This was first documented by Karl von Frisch in 1938 and described in detail by Wolfgang Pfeiffer in 1963 and 1977. The alarm substance (Schreckstoff) is a pheromone that is chemically similar or identical in all ostariophysans and is produced from epidermal club cells. injuries to the skin release the alarm substance, which is detected by the sense of smell and causes a fright reaction in nearby members of the same species (or sometimes in related species). Some members of this superorder lack the fright reaction but possess an alarm substance (e.g., Serrasalminae) or lack both the alarm substance and the fright reaction to alarm substances of other species (e.g., Loricariidae and Gymnotiformes).
The recognition of five major lineages and their sequencing follows Fink and Fink (1981), although they recognized the siluriforms and gymnotiforms as suborders of the order Siluriformes. They postulated, as is still accepted, gymnoti-forms to be siluriform derivatives and characiforms to be the primitive sister group of both, with cypriniforms being more primitive than this assemblage.
This superorder is divided into two series, the Anotophysi and the Otophysi. As a word of warning, in older literature the term Ostariophysi is restricted to what is herein recognized as the otophysi.
Five orders, 68 families, 1,075 genera, and about 7,931 species. The four largest families—Cyprinidae, Characidae, Loricariidae, and Balitoridae— account for 4,656 (or 59%) of the species. The ostariophysans contain about 28% of the known fish species in the world while accounting for about 68% of the freshwater species. They are present on all continents and major land masses except Antarctica, Greenland, and New Zealand (Australia has a few catfishes secondarily derived from marine groups). About 123 species are marine (the chanid, the gonorynchids, half of the plotosids, and most ariids).
Order GONORYNCHIFORMES (28)—milkfishes. Orbitosphenoid absent; parietals small; quadrate condyle far forward; teeth absent on fifth cerato-branchial; first three vertebrae specialized and associated with one or more cephalic ribs (this represents a primitive Weberian apparatus, as shown in 1970 by D. E. Rosen and P. H. Greenwood); suprabranchial (= epibranchial) organ present (consisting of lateral pouches in the posterior part of the branchial chamber behind the fourth epibranchials); mouth small; jaws toothless; no postcleithra; 5-7 hypural plates.
Monophyly has been shown by T. Grande and Poyato-Ariza (1995, 1999). The classification of this order is based on the cladistic analysis of fossil and extant material by Grande and Poyato-Ariza (1999). The latter study was also used as the basis for the biogeographical study of Grande (1999a). Many Cretaceous gonorynchiform taxa have been described by Louis Taverne from Italy as follows: Apulichthys (considered to be the primitive sister group to all other gonorynchoids), Lecceichthys (in 1998 and considered to be the sister to Notogoneus and Gonorynchus), and Sorbininardus (in 1999 and placed in its own family, Sorbininardidae, and order, Sorbininardiformes, and considered primitive and sister to the Gonorynchiformes).
Four families, seven genera, and about 37 species (of which 31 are freshwater).
Suborder Chanoidei. Early Cretaceous fossils of gonorynchiforms represent some of the earliest well-known clupeocephalans, including Aethalinopsis (Belgium), regarded as sister to Chanidae (Grande and Poyato-Ariza, 1999).
Family CHANIDAE (98)—milkfishes. Marine and brackish (occasionally freshwater); tropical and subtropical Indian and Pacific (rare in eastern Pacific from southern California to Peru).
Mouth cleft small; jaws without teeth. The following two subfamilies are recognized following Poyato-Ariza (1996a) and Grande and Poyato-Ariza (1999).
fSuBFAMiLY Rubiesichthyinae. Two Early Cretaceous fossil genera, Gordichthys (Spain) and Rubiesichthys (Spain) (Poyato-Ariza, 1996b).
Subfamily Chaninae. Body compressed; mouth terminal; nonprotractile upper jaw; cycloid scales, 78-90 in lateral line; dorsal fin rays 13-17; anal fin rays 9-11; pelvic fin rays 10-12; branchiostegal rays four; swim bladder present.
Milkfish spawn in the ocean, but metamorphosis from the ribbonlike larval stage occurs in brackish water. They are of considerable importance as a food fish in Southeast Asia. in the Philippines (where they are known as bangos, bangus, or sabalo), indonesia, and Taiwan, especially, there is an extensive fishpond culture for them. Young are caught close to shore and reared in coastal ponds. Breeding, however, does not occur in the ponds. Females are highly fecund and can lay millions of eggs. Adults feed primarily on algae. Maximum length 1.8 m, usually 1.0 m.
Early Cretaceous fossil genera include Dastilbe (Brazil and Equatorial Guinea), Parachanos (Gabon), and Tharrhias (Brazil, and sister to Chanos). One species, Chanos chanos (e.g., Poyato-Ariza, 1996a).
Family GONORYNCHIDAE (99)—beaked sandfishes. Marine; Indo-Pacific, rare in southern Atlantic (e.g., St. Helena).
Body elongate; mouth inferior; protractile upper jaw; single barbel at tip of pointed snout; ctenoid scales on body and head, about 140-170 in lateral line; dorsal (11-13 rays) and anal (9 or 10 rays) fins posteriorly placed; branchiostegal rays four or five; no swim bladder. Maximum length 60 cm.
Fossil gonorynchid genera include Notogoneus (North America, Europe, Australia, some freshwater, Late Cretaceous to Oligocene, sister to Gonorynchus) and the Cretaceous Charitosomus (Germany, Lebanon), Judeichthys (israel), Ramallichthys (israel), and Charitopsis (Lebanon) (Poyato-Ariza, 1996; Grande, 1996, 1999a; Grande and Grande, 1999; Grande and Poyato-Ariza, 1999.
One genus, Gonorynchus, with five species (Grande, 1999b). Unlike in Nelson (1994), the correct generic spelling is Gonorynchus (not Gonorhynchus) and the correct family spelling is Gonorynchidae (not Gonorhynchidae), according to Eschmeyer (1998 and Online version, January 2005).
Suborder Knerioidei. Branchiostegal rays usually three; swim bladder present and used in respiration in some species at least; supraoccipital with prominent cartilaginous margin.
Family KNERIIDAE (100)—knerias. Freshwater; tropical Africa and Nile.
Mouth inferior or subterminal; protractile upper jaw; pelvic rays 6-9. Kneria and Parakneria have cycloid scales and a lateral line, whereas the small and transparent species of the monotypic Cromeria and Grasseichthys have a naked body and lack a lateral line. Maximum length about 15 cm (attained in Parakneria marmorata of Angola).
Four genera with 30 species, Cromeria nilotica, Grasseichthys gabonensis, Kneria (13 species), and Parakneria (15 species) (Poll, 1984a, b; Seegers, 1995). Cromeria and Grasseichthys were recognized in separate families (i.e., Cromeriidae, Grasseichthyidae) by Poll (1984a) and Poll and Gosse (1995). However, Grande (1994) considered all part of a monophyletic group and placed Cromeria and Grasseichthys in one clade and Kneria and Parakneria in the other. Grande and Poyato-Ariza (1999) supported these relationships, and in addition, showed that Phractolaemus is the sister group these four genera; however, unlike these authors, I do not place Phractolaemus in its own subfamily within the Kneriidae.
Family PHRACTOLAEMIDAE (101)—snake mudheads. Freshwater; tropical Africa (Niger Delta and Malebopool and Zaire systems).
Mouth superior; quadrate positioned near anterior tip of head; protractile upper jaw; pelvic rays six; cycloid scales; body elongate; dorsal and anal fin rays about six; esophagus with numerous folds; swim bladder divided into numerous small alveoli and adapted to airbreathing; single median abdominal vein resulting from fusion of the iliac veins. Maximum length about 16 cm.
One species, Phractolaemus ansorgii (D. F. E. Thys van den Audenaerde, in Daget et al, 1984; Poll and Gosse, 1995). It is also known as the African Mudminnow.
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