Arowanas are freshwater bony fish of the subfamily Osteoglossinae, also known as bony tongues. In this family of fish, the head is bony and the elongated body is covered by large, heavy scales, with a mosaic pattern of canals. The dorsal and anal fins have soft rays and are long based, while the pectoral and ventral fins are small. The name "bonytongues" is derived from a toothed bone on the floor of the mouth, the "tongue", equipped with teeth that bite against teeth on the roof of the mouth. The arowana is a facultative air breather and can obtain oxygen from air by sucking it into its swim bladder, which is lined with capillaries like lung tissue.
The Asian arowana comprises several phenotypic varieties of freshwater fish distributed geographically across Southeast Asia. While most consider the different varieties to belong to a single species, work by Pouyaud et al. (2003) differentiates these varieties into multiple species. They have several other common names, including Asian bonytongue, dragonfish, and a number of names specific to the different color varieties.
The Zeiformes are a small order of exclusively marine ray-finned fishes most notable for the dories, a group of common food fish. The order consists of about 33 species in six extant families, mostly deep-sea types. The boarfishes (Caproidae) have been previously included in this order though they are currently included in the Perciformes.
Osteoglossidae is a family of large-sized freshwater fish, which includes the arowanas. They are commonly known as bonytongues. The family has been regarded as containing two extant subfamilies Arapaiminae and Osteoglossinae, with a total of five living genera, but these are regarded as valid families in Eschmeyer's Catalog of Fishes The extinct Phareodontinae are known from worldwide during the Late Cretaceous and Paleogene; they are generally considered to be crown group osteoglossids that are more closely related to one of the extant osteoglossid subfamilies than the other, though their exact position varies.
The Asiatic glassfishes are a family, the Ambassidae, of freshwater and marine ray-finned fishes that were formerly classified in the order Perciformes, but most authorities consider this order to be paraphyletic and that the Ambassidae are of uncertain affinities, incertae sedis, but within the subseries Ovalentaria. The species in the family are native to Asia, Oceania, the Indian Ocean, and the western Pacific Ocean. The family includes eight genera and about 51 species. Some species are known as perchlets.
The Carangidae are a family of ray-finned fish that includes the jacks, pompanos, jack mackerels, runners, trevallies, and scads. It is the largest of the six families included within the order Carangiformes. Some authorities classify it as the only family within that order but molecular and anatomical studies indicate that there is a close relationship between this family and the five former Perciform families which make up the Carangiformes.
Scleropages is a genus of fish in the family Osteoglossidae found in Asia and Australia. All of these species are carnivorous and have great jumping ability. These species are highly valued as aquarium fish, particularly by those from Asian cultures. In 2003, a study redescribed several naturally occurring color varieties of S. formosus into four separate species. The majority of researchers dispute these redescriptions, arguing that the published data are insufficient to justify recognizing more than one Southeast Asian species of Scleropages and that divergent haplotypes used to distinguish the color strains into isolated species were found within a single color strain, contradicting the findings. They are considered monotypic, consisting of closely related haplotypes based on color. The ancestor of the Australian arowanas: S. jardinii and S. leichardti, diverged from the ancestor of the Asian arowanas about 140 million years ago, during the Early Cretaceous period. The morphological similarity of all seven species shows that little evolutionary change has taken place recently for these ancient fish. The genus had a much wider distribution during the early Cenozoic, with fossil remains known from the Paleocene of Niger and Belgium, and from the Eocene of China.
Streptocephalus proboscideus, sometimes called the Sudanese fairy shrimp, is a species of fairy shrimp found in eastern Africa.
Terricola is a subgenus of voles in the genus Microtus. The authority for this taxon is Fatio in 1867. Earlier use of the name by John Fleming has no formal taxonomic standing. Species in this subgenus are:
Chirocentrites is an extinct genus of marine ray-finned fish in the order Ichthyodectiformes. It contains a single species, C. coroninii, from the Late Cretaceous (Cenomanian) of Slovenia. A potential specimen is also known from the Albian-aged Pietraroja Plattenkalk of southern Italy, but it has been suggested that this specimen actually represents Cladocyclus.
Chanopsis is an extinct genus of prehistoric freshwater bonytongue relative that lived from the late Aptian to the Albian stage of the Early Cretaceous epoch. It contains a single species, C. lombardi from the Democratic Republic of the Congo.
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. Almost nothing is known about it.
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.
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.
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.
Dapalis is an extinct genus of prehistoric glassfish known from the Late Cretaceous to the Early Miocene. It is known from both freshwater and marine habitats of India, Australia, New Zealand, and much of mainland Europe.
Platinx is an extinct genus of marine ray-finned fish that inhabited the northern Tethys Ocean during the early to middle Eocene. It was the last surviving member of the ancient order Crossognathiformes, which was a dominant and successful group throughout the preceding Mesozoic era.
Autocrates is a genus of beetles in the Trictenotomidae family with species across the Indomalayan realm. They are sexually dimorphic with males having longer and more sinuate mandibles.
Monopteros is an extinct genus of marine bonytongue fish known from the Eocene. It contains a single species, M. gigas, known from the Early Eocene of Monte Bolca, Italy. Its genus name, Monopteros meaning "one wing", comes from its large, elongated pectoral fins. The species name, gigas, refers to its relatively large size at 448 millimetres (1.470 ft) in length.
The Sankarewang Formation is an ?Eocene-aged geological formation in Sumatra, Indonesia near Padang. It is among the very few Paleogene fossil deposits from Southeast Asia that preserves a freshwater ecosystem, and contains many of the earliest records of freshwater fish taxa that now predominate the region. Many of the fishes from this formation are well-preserved as articulated skeletons. The fossils of the formation have been known since the 1870s, although they only received significant attention during the 1930s and again starting from the mid-2010s.
