''Asteracanthus'' (from el, ἀστήρ , 'star' and el, ἄκανθα , 'spine') is an extinct genus of hybodontiform, known from the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

(

Bathonian In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Strat ...

) to the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

(

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceou ...

Description

Astercanthus was among the largest known

hybodontiformes Hybodontiformes, commonly called hybodonts, are an extinct group of shark-like chondrichthyans, which existed from the late Devonian to the Late Cretaceous. They form the group of Elasmobranchii closest to neoselachians, the clade of modern shar ...

, reaching a length of 2-3 metres. The dentition of ''Astercanthus'' is high crowned and multicusped.

Fossil records

This genus has been reported from the

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...

to the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

, though the genus as currently circumscribed dates from the

, predominantly of Europe. Fossils are found in the marine strata of United States, Iran, Switzerland, Madagascar, Morocco and Europe. A complete skeleton was described in 2021 from the Late Jurassic (

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...

) aged Solnhofen Limestone. Previously considered synonymous, the genus ''

Strophodus ''Strophodus'' is an extinct genus of hybodonts known from the Triassic to Cretaceous. It has heavily rounded, durophagous teeth. It has long been confused with ''Asteracanthus'' due to the fin spines of the latter being found associated with the ...

'' (Middle Triassic-Late Cretaceous) is now considered distinct, with the teeth of ''Asteracanthus'' having more in common with ''

Hybodus ''Hybodus'' (from el, ύβος , 'crooked' and el, ὀδούς 'tooth') is an extinct genus of hybodont, a group of shark-like elasmobranchs that lived from the Late Devonian to the end of the Cretaceous. Species closely related to the type sp ...

'' and '' Egertonodus.''

Life habits

The genus seems to have been adapted for open marine conditions and likely had an

epibenthic Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.

Species

Species within this genus include:Paleobiology Database
/ref> *''Asteracanthus acutus'' Agassiz 1837 *''Asteracanthus aegyptiacus'' Stromer, 1927 *''Asteracanthus granulosus'' Egerton 1854 *''Asteracanthus magnus'' Agassiz 1838 *''Asteracanthus medius'' Owen 1869 *''Asteracanthus minor'' Agassiz 1837 *''Asteracanthus ornatissimus'' Agassiz 1837 *''Asteracanthus papillosus'' Egerton 1854 *''Asteracanthus semisulcatus'' Agassiz 1837 *''Asteracanthus siderius'' Leidy 1870 *''Asteracanthus somaensis'' Yabe 1902 *''Asteracanthus tenuis'' Agassiz 1838 *''Asteracanthus udulfensis'' Leuzinger ''et al.'' 2017

References

*L. Agassiz. 1837. Recherches Sur Les Poissons Fossiles. Tome III (livr. 8–9). Imprimérie de Petitpierre, Neuchatel viii-72 Hybodontiformes Triassic fish of Europe Permian fish of North America Devonian first appearances Cretaceous extinctions Devonian sharks Carboniferous sharks Permian sharks Triassic sharks Jurassic sharks Cretaceous sharks Prehistoric shark genera Fossil taxa described in 1837 Taxa named by Louis Agassiz {{Cretaceous-fish-stub