''Scheenstia'' is an extinct genus of

neopterygian Neopterygii (from Greek νέος ''neos'' 'new' and πτέρυξ ''pteryx'' 'fin') is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant f ...

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

from the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

–

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

of Europe. Fossils have been found in both marine and freshwater environments. Most species of the genus were previously referred to the related genus ''

Lepidotes ''Lepidotes'' (from , 'covered with scales') (previously known as ''Lepidotus'') 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 ...

'', but most

–

species of that genus have since been re-classified as ''Scheenstia'' following detailed phylogenetic analysis. It is a member of

Lepisosteiformes Lepisosteiformes is an order of ray-finned fish and the only living members of the clade Ginglymodi. Its only extant representatives are the gar (family Lepisosteidae), and it is defined as all members of Ginglymodi that are more closely rela ...

meaning that its closest living relatives are

gar Gars are an ancient group of ray-finned fish in the family Lepisosteidae. They comprise seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine waters of eastern North America, Central America and Cuba ...

s. The teeth of ''Scheenstia'' are low and rounded, and were likely used for crushing hard shelled organisms (

durophagy Durophagy is the eating behavior of animals that consume Seashell, hard-shelled or exoskeleton-bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including ...

). The teeth were replaced synchronously, undergoing a 180 degree rotation during development, unique among vertebrates. It was probably a relatively slow swimmer that was capable of making fine movements in order to remove prey from the seafloor. One species, the marine ''Scheenstia maximus'' from the Late Jurassic of Germany, could reach body lengths in excess of , likely up to . The teeth of ''Scheenstia'' were historically known as

toadstone The toadstone, also known as bufonite (from Latin , "toad"), is a mythical stone or gem that was thought to be found in the head of a toad. It was supposed to be an antidote to poison and in this it is like batrachite, supposedly formed in th ...

s, and were attributed magical and medicinal properties in medieval Europe, with some being incorporated into jewelry, including on a crown held at

Aachen Cathedral Aachen Cathedral () is a Catholic Church, Catholic church in Aachen, Germany and the cathedral of the Diocese of Aachen. One of the oldest cathedral buildings in Europe, it was constructed as the royal chapel of the Palace of Aachen of Holy Rom ...

used to crown

Charles IV, Holy Roman Emperor Charles IV (; ; ; 14 May 1316 – 29 November 1378''Karl IV''. In: (1960): ''Geschichte in Gestalten'' (''History in figures''), vol. 2: ''F–K''. 38, Frankfurt 1963, p. 294), also known as Charles of Luxembourg, born Wenceslaus (, ), was H ...

.Gregorová, R., Bohatý, M., Stehlíková, D., Duffin, Ch., 2020: “Crapaudine” (Scheenstia teeth) - the jewel of Kings. – Acta Musei Moraviae, Scientiae geologicae, 105, 2, 277–294 (with Czech summary).

Classification

''Scheenstia'' is related to the genus ''

'', with both genera placed in the family

Lepidotidae Lepidotidae is an extinct family of fish, known from the Jurassic and Cretaceous periods. Most species were originally assigned to the genus ''Lepidotes'' which was long considered a wastebasket taxon. Cladistic analysis has indicated that they ar ...

. ''Lepidotes'' has been one of the greatest actinopterygian

wastebasket taxa Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the purpose of classifying organisms that do not fit anywhere else. They are typically defined by e ...

, with one 2012 study finding species referrable to a minimum of three different and distantly related genera. ''Scheenstia'' is also related to '' Isanichthys''. A cladogram showing the relations of

Neopterygii Neopterygii (from Greek νέος ''neos'' 'new' and πτέρυξ ''pteryx'' 'fin') is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant ...

was published in the review, and a simplified version labelling the previous species of ''Lepidotes'' is shown here. Some studies have suggested that ''Scheenstia'' may be

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

with respect to the lepidotid genera '' Camerichthys'' and '' Isanichthys.''

References

Lepisosteiformes Prehistoric holostei Prehistoric ray-finned fish genera Cretaceous bony fish Mesozoic fish of Europe Fossil taxa described in 2011 {{Cretaceous-fish-stub