| Wakinoichthys Temporal range: Early Cretaceous | |
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| Life reconstruction of W. aokii | |
| Scientific classification | |
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| Family: | Wakinoichthiidae |
| Genus: | Wakinoichthys Yabumoto, 1994 |
| Species | |
W. aokii Yabumoto, 1994 W. robustus Yabumoto, 1994 | |
Wakinoichthys is a small freshwater fish from the Early Cretaceous of South Korea [1] and Japan. Two species are currently known: W. aokii and W. robustus.
The first specimens of Wakinoichthys have been discovered in the Wakino Subgroup, a part of the Kanmon Group from Kitakyushu in 1994. [2] Starting in 1977 Japanese and Korean researchers have cooperated in excavating fossils from the from Gyeongsang Supergroup, previously known to have yielded the fossils of plants and molluscs. In these collaborative efforts multiple fossil fish had been discovered, including a specimen of Wakinoichthys. [1]
The generic name derives from the Wakino Subgroup and ichthys, the Greek word for fish. W. aokii was named for Mr. Tateyu Aoki, who collected and donated the specimens to the Kitakyushu Museum and Institute of Natural History, while W. robustus was named for its more robust build compared to its relative. [2]
Wakinoichthys aokii was a proportionally long and slender fish, reaching lengths between 7–12 cm (2.8–4.7 in) which are 6.4 times longer than its body depth. The median fins are positioned relatively posterior and the dorsal fin's origin lies behind that of the anal fin. The base of the dorsal fin is about half the length of the anal fin's base. The pectoral fins are elongated with a stout first pectoral fin ray. The pelvic fin is located at the centre of the abdoman and the caudal fin is forked. Wakinoichthys had long lower jaws that housed small canine-like teeth, while those of the upper jaw were larger and more pronounced. The endopterygoid meanwhile housed villiform teeth. [2] [1]
W. robustus differs from W. aokii due to its more robust build. Its total body length is only 3.8 times longer than its body depth and with a proportionally bigger head. The dorsal outline of the skull is slightly convex. The holotype specimen of W. robustus is 3.86 cm (1.52 in) long, while the other specimen are typically smaller. [2]
Yabumoto assigns Wakinoichthys to the order of the Osteoglossiformes, which includes the modern arowana, butterflyfish, elephantfish and knifefish based on a series of characters such as the position of the median fins, dentition of the premaxilla and dentary and villiform endopterygoid teeth among other morphological traits. [2]
Apsopelix is an extinct genus of ray-finned fish that existed about 95-80 million years ago in the shallow waters of the Western Interior Seaway, Hudson Seaway, England, France, and Japan.
St. Paul's fingerfin, is a species of marine ray-finned fish, traditionally regarded as belonging to the family Cheilodactylidae, the members of which are commonly known as morwongs. It is native to the southwestern Indian Ocean and southeastern Atlantic Ocean.
This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes.
Lepidotes is an extinct genus of Mesozoic ray-finned fish. It has long been considered a wastebasket taxon, characterised by "general features, such as thick rhomboid scales and, for most of the species, by semi-tritorial or strongly tritorial dentition". with dozens of species assigned to it. Fossils attributed to Lepidotes have been found in Jurassic and Cretaceous rocks worldwide. It has been argued that Lepidotes should be restricted to species closely related to the type species L. gigas, which are only known from the Early Jurassic of Western and Central Europe, with most other species being not closely related, with other species transferred to new genera such as Scheenstia.Lepidotes belongs to Ginglymodi, a clade of fish whose only living representatives are the gars (Lepisosteidae). The type species L. gigas and close relatives are thought to be members of the family Lepidotidae, part of the order Lepisosteiformes within Ginglymodi, with other species occupying various other positions within Ginglymodi.
The longfin mako shark is a species of mackerel shark in the family Lamnidae, with a probable worldwide distribution in temperate and tropical waters. An uncommon species, it is typically lumped together under the name "mako" with its better-known relative, the shortfin mako shark. The longfin mako is a pelagic species found in moderately deep water, having been reported to a depth of 220 m (720 ft). Growing to a maximum length of 4.3 m (14 ft), the slimmer build and long, broad pectoral fins of this shark suggest that it is a slower and less active swimmer than the shortfin mako.
Rhizodontida is an extinct group of predatory tetrapodomorphs known from many areas of the world from the Givetian through to the Pennsylvanian - the earliest known species is about 377 million years ago (Mya), the latest around 310 Mya. Rhizodonts lived in tropical rivers and freshwater lakes and were the dominant predators of their age. They reached huge sizes - the largest known species, Rhizodus hibberti from Europe and North America, was an estimated 7 m in length, making it the largest freshwater fish known.
The Pondicherry shark is an extremely rare species of requiem shark, in the family Carcharhinidae. A small and stocky gray shark, it grows not much longer than 1 m (3.3 ft) and has a fairly long, pointed snout. This species can be identified by the shape of its upper teeth, which are strongly serrated near the base and smooth-edged near the tip, and by its first dorsal fin, which is large with a long free rear tip. Furthermore, this shark has prominent black tips on its pectoral fins, second dorsal fin, and caudal fin lower lobe.
The smoothtooth blacktip shark is a species of requiem shark in the family Carcharhinidae. It is known only from the type specimen caught from the Gulf of Aden, off eastern Yemen, and a handful of additional specimens caught from the Persian Gulf, off Kuwait. Reaching 1.3 m (4.3 ft) in length, this species has a stocky greenish-colored body, a short snout, and black-tipped fins. It can be distinguished from similar species by its teeth, which are narrow, erect, and smooth-edged.
Diplomystus is an extinct genus of freshwater clupeomorph fish distantly related to modern-day extant herrings, alewives, and sardines. The genus was first named and described by Edward Drinker Cope in 1877. There are seven species of Diplomystus: D. dentatus, D. birdii, D. dubetreiti, D. shengliensis, D. kokuraensis, D. primotinus, and D. altiformis.
Mawsonia is an extinct genus of prehistoric coelacanth fish. It is amongst the largest of all coelacanths, with one quadrate specimen possibly belonging to an individual measuring 5.3 metres in length. It lived in freshwater and brackish environments from the late Jurassic to the mid-Cretaceous of South America, eastern North America, and Africa. Mawsonia was first described by British paleontologist Arthur Smith Woodward in 1907.
Paleopsephurus is an extinct genus of paddlefish (Polyodontidae). At present the genus contains the single species Paleopsephurus wilsoni. The genus is known from the Late Cretaceous (Maastrichtian) aged Hell Creek Formation of Montana.
Mesoclupea showchangensis is an extinct ichthyodectiform ray-finned fish that lived in freshwater environments in what is now China during the Early Cretaceous epoch. It differs from its sister genus, Chuhsiungichthys, primarily by having a more posteriorly-placed dorsal fin.
Toxotes kimberleyensis is a species of archerfish found in the Kimberley region of Western Australia. It was first named by Gerald R. Allen in 2004, and is commonly known as the Kimberley archerfish, largescale archerfish, or western archerfish.
Sinamia is an extinct genus of freshwater amiiform fish which existed in China, Japan, and possibly South Korea during the Early Cretaceous period. Like the related bowfin, it has an elongated low-running dorsal fin, though this was likely convergently evolved.
Chuhsiungichthys is an extinct genus of ichthyodectiform ray-finned fish that lived in freshwater environments in what is now Yunnan, China, and Kyushu, Japan, during the Cretaceous. It differs from its sister genus, Mesoclupea, primarily by having a comparatively more anteriorly-placed dorsal fin.
Aokiichthys is an extinct genus of basal osteoglossoid from an Early Cretaceous freshwater palaeolake of what is now Kyushu, Japan. The genus formed a species radiation in the First Formation within the Wakino Subgroup of the Kwanmon Group, as a dominant member and namesake of the Nipponamia-Aokiichthys fauna. The genus became extinct at the end of either the 1st Formation, or possibly during the 2nd Formation, when the palaeolake became shallower.
Nomorhamphus ebrardtii is a species of viviparous halfbeak, a ray-finned fish in the family Zenarchopteridae, endemic to brackish and freshwater locations in Sulawesi and the neighbouring island of Kabaena in Indonesia. This species can reach a length of 9 cm (3.5 in) SL.
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Pentanogmius is an extinct genus of sail-finned ray-finned fish that lived during the Late Cretaceous in what is now Europe and the United States. Five species are currently recognized, 2 from Cenomanian to Turonian Europe and 3 better known species from Coniacian to Campanian North America. The American species inhabited large areas of the Western Interior Seaway, with fossil finds indicating a range from Texas and Alabama in the south to Manitoba, Canada, in the north.
Archolaemus luciae is a species of glass knifefish endemic to Brazil where it is found in the Rio Jari, the Rio Trombetas and the Rio Tapajós basins in the eastern Amazon. Also found in the Rio Araguari. This species reaches a length of 49.7 cm (19.6 in).
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