''Pseudorhina'' is an extinct genus of stem
angel shark
The angelsharks are a group of sharks in the genus ''Squatina'' of the family Squatinidae. They commonly inhabit sandy seabeds close to in depth. Many species are now classified as critically endangered by the International Union for Conservat ...
seemingly restricted to the
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
of
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
. It is represented by several articulated individuals as well as isolated teeth. There are four species.
Taxonomy and relationships
''Pseudorhina'' is currently the oldest known angel shark genus. It is thought to represent a basal offshoot within Squatiniformes and has been placed in a monotypic family called Pseudorhinidae. While most fossil genera and species of angel shark are represented solely by isolated teeth, ''Pseudorhina'' is relatively well known from articulated individuals. This allows a rare opportunity for detailed comparisons with other genera known from articulated remains including the extant
''Squatina''.
[Maisey, J. G., Ehret, D. J., & Denton, J. S. (2020). A new genus of Late Cretaceous angel shark (Elasmobranchii; Squatinidae), with comments on squatinid phylogeny. ''American Museum Novitates'', ''2020''(3954), 1-29.] Modern angel sharks are much more specialized than ''Pseudorhina'', neurocrania show little morphological disparity in extant ''Squatina''.
Distribution and temporal range
All late Jurassic angel shark teeth currently known are attributed to ''Pseudorhina''. The genus is currently restricted to Europe. ''P. acanthoderma'' is known from the late
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...
of
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
in layers which produce
ammonites
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttl ...
such as ''
Hybonoticeras beckeri'' and ''
Lithacoceras ulmense''. It is known from both isolated teeth and associated material. ''P. alifera'' is known from the early
Tithonian of Germany and similar teeth currently labeled as ''P. aff. alifera'' have been described from the
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 Cretace ...
of
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...
. Associated specimens are known. There seems to be another undescribed species with a unique tooth morphologynfrom the Tithonian of Germany. ''P. frequens'' is known only from isolated teeth from the early Kimmeridgian. ''P. crocheti'' is known from more than 250 isolated teeth from the Valanginian of France.
[Guinot, G., Cappetta, H., & Adnet, S. (2014). A rare elasmobranch assemblage from the Valanginian (Lower Cretaceous) of southern France. ''Cretaceous Research'', ''48'', 54-84.]
Gallery
References
{{Taxonbar, from=Q1557969
Prehistoric cartilaginous fish genera
Squatiniformes