| Baleiichthys Temporal range: | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Division: | Teleostei |
| Genus: | † Baleiichthys Rohon, 1890 |
| Species | |
| |
Baleiichthys is a genus of extinct freshwater ray-finned fish, belonging to the teleosts. It lived in the Middle Jurassic, and its fossil remains have been found in northern Asia. [1] Almost nothing is known about it. [2] [3]
Baleiichthys was small in size and had an elongated and slender body, up to 7 centimeters long. The head was low, with small eyes and rather large jaws. The dorsal fin was placed approximately halfway down the body, obliquely opposite the small anal fin, which was triangular in shape. The pectoral fins were small and fan-shaped. The caudal fin was slightly forked. The body was covered in rather thick scales, arranged in diagonal rows, with a serrated rear edge. There were numerous fringed fulcrums along the margins of the unpaired fins. [2]
Baleiichthys was described by Rohon in 1890, based on fossil remains found in formations dating back to the early-middle Jurassic in the Baleysky District in Siberia; the type species is Baleiichthys graciosa, but the slightly larger species B. lata also comes from the same sediments. Another species, B. antingensis, is known from the Middle Jurassic Anting Formation in Shaanxi Province, China. [2] [3] [4]
Baleiichthys was previously thought to be a member of the pholidophoriforms, a large group of fishes at the base of the teleosts that are known to have ganoid scales. Subsequent research has found substantial differences between Baleiichthys and the Pholidophorus genus and related forms; currently Baleiichthys is considered an archaic representative of teleosts, outside the group of pholidophoriforms proper. [2] Sepkoski (2002) incorrectly referred to it as a pachycormiform. [1] [5]
Leedsichthys is an extinct genus of pachycormid fish that lived in the oceans of the Middle to Late Jurassic. It is the largest ray-finned fish, and amongst the largest fish known to have ever existed.
Pholidophorus is an extinct genus of stem-teleost fish. Numerous species were assigned to this genus in the past, but only the type species Pholidophorus latiusculus, from the Late Triassic of Europe, is considered to be a valid member of the genus today.
Pachythrissops is an extinct genus of ray-finned fish. It contains two species, P. laevis from the Purbeckian of England and P. propterus from the Tithonian of Germany. A third species, P. vectensis, has been reassigned to the elopiform genus Arratiaelops. Pachythrissops is often regarded as one of the most primitive members of the order Ichthyodectiformes; however, a phylogenetic analysis by Cavin et al. (2013) placed it and the related genus Ascalabothrissops outside the group.
Pycnodontiformes is an extinct order of primarily marine bony fish. The group first appeared during the Late Triassic and disappeared during the Eocene. The group has been found in rock formations in Africa, Asia, Europe, North and South America. They were small to middle-sized fish, generally with laterally-compressed deep bodies, some with almost circular outlines, adapted for manuverability in reef-like environments, though the group was morphologically diverse. Most, but not all members of the groups had jaws with round and flattened teeth, well adapted to crush food items (durophagy), such as echinoderms, crustaceans and molluscs. Some pyncodontiformes developed piranha like teeth used for eating flesh. Most species inhabited shallow marine reef environments, while a handful of species lived in freshwater or brackish conditions. While rare during the Triassic and Early-Middle Jurassic, Pycnodontiformes became abundant and diverse during the Late Jurassic, exhibiting a high but relatively static diversity during the Early Cretaceous. At the beginning of the Late Cretaceous they reached their apex of morphological and species diversity, after which they began to gradually decline, with a more sudden decline at the end of the Cretaceous due to the collapse of reef ecosystems, finally becoming extinct during the Eocene. They are considered to belong to the Neopterygii, but their relationship to other members of that group is uncertain.
Neopholidophoropsis is an extinct genus of stem-teleost ray-finned fish that lived in what is now Germany during the Aptian stage of the Early Cretaceous epoch. It contains one species, Neopholidophoropsis serrata.
Aphnelepis is an extinct genus of prehistoric freshwater ray-finned fish that lived during the Late Jurassic epoch. It contains a single species, A. australis, from the Talbragar River beds of New South Wales, Australia.
Ligulella is an extinct genus of ray-finned fish that lived in what is now the Democratic Republic of the Congo during the Middle Jurassic epoch. It contains one species, Ligulella sluysi. Ligulella is the only member of the family Ligulellidae and the order Ligulelliformes.
Austropleuropholis is an extinct genus of freshwater ray-finned fish that lived during the Middle Jurassic epoch. It contains a single species, A. lombardi, from the Democratic Republic of the Congo, from the terrestrial/freshwater series of the Stanleyville Formation.
Opsithrissops is an extinct genus of prehistoric bony fish that lived during the Thanetian stage of the Paleocene epoch. It is a 120 centimetres (3.9 ft) fish in the family Osteoglossiformes which includes other bony-tongues such as the extant species of arowana and arapaima.
Anaethalion is an extinct genus of prehistoric marine and freshwater ray-finned fish related to modern tarpons and ladyfish. It is known from the Late Jurassic to the Early Cretaceous of Europe and northeasterrn Asia, roughly encompassing the Tethys Ocean.
Ankylophorus is an extinct genus of stem-teleost ray-finned fish that lived in what is now France during the Late Jurassic. Its type and only species, Ankylophorus similis, was originally named in 1895 as a species of Pholidophorus, but was moved to a separate genus in 1978.
Brychaetus is an extinct genus of prehistoric marine bonytongue fish known from the Late Cretaceous to the late Eocene of Europe, North America, and northern Africa.
Ceramurus is an extinct genus of prehistoric marine ray-finned fish from the Late Jurassic. It contains a single species, C. macrocephalus from the Purbeck Group of England.
Pholidophoristion is an extinct genus of stem-teleost ray-finned fish that lived in what is now Europe from the Late Jurassic to the Early Cretaceous.
Crossognathiformes is an extinct order of ray-finned fish that lived from the Late Jurassic to the Eocene. Its phylogenetic placement is disputed; some authors have recovered it as part of the teleost stem group, while others place it in a basal position within crown group Teleostei.
Gebrayelichthyidae is a family of extinct pycnodontid fish, with a superficially shrimpfish-like appearance that lived during the lower Cenomanian.
The Sainte-Barbe Clays Formation is a geological formation in Belgium. It is found in localised areas of the northern margin of the Mons Basin, alongside the equivalently aged Hautrage and Baudour Clay Formations. It is Upper Barremian-Lower Aptian in age. It predominantly consists of laminated clay, with some lignite. It is well known for the "Iguanodon sinkhole" locality near Bernissart where many specimens of Iguanodon bernissartensis were described by Louis Dollo in the late 19th century.
Pholidophoridae is an extinct family of primitive stem-teleost fish that lived during the Triassic period, from the Anisian age of the Middle Triassic to the Norian age of the Late Triassic. Most of the genera are from Europe, but one (Malingichthys) is known from China. The pholidophorids were historically united with several other stem-teleost lineages into the order Pholidophoriformes, but Pholidophoriformes in its traditional sense is now considered paraphyletic with respect to crown group teleosts.
 | This article about a prehistoric ray-finned fish is a stub. You can help Wikipedia by expanding it. |
 | This article related to a Jurassic animal is a stub. You can help Wikipedia by expanding it. |