''Steneosaurus'' (from el, στενός , 'narrow' and el, σαῦρος , 'lizard') is a dubious

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of teleosaurid crocodyliform from the

Middle Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek (d ...

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the ...

(

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

or early Oxfordian) 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 ar ...

. The genus has been used as a

wastebasket taxon 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 sole purpose of classifying organisms that do not fit anywhere else. They are typically define ...

for thalattosuchian fossils for over two centuries, and almost all known historical species of teleosauroid have been included within it at one point. The genus has remained a wastebasket, with numerous species still included under the label ''‘Steneosaurus’'', many of which are unrelated to each other (either

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

with respect to each other and other genera of teleosauroids).

Discovery and assigned species

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

, ''S. rostromajor'', was only formally recognised as such in 2020, and this revision determined the

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

of ''Steneosaurus'' was undiagnostic, and so declared the genus ''Steneosaurus'' a ''nomen dubium''. The history of this specimen has been detailed in 2017. It was discovered in three pieces by abbot Charles Bacheley (1716-1795) in the Vaches Noires near Villers-sur-Mer (Calvados, France). Bacheley offered these pieces to Alexandre Besson (1725-1809) who had built up an important cabinet of fossils and minerals in Paris. Besson gave one of the pieces (the posterior portion) to Barthélémy Faujas de Saint-Fond (1841-1819), professor of geology in the Muséum national d'Histoire naturelle, Paris. Georges Cuvier first illustrated in 1808 the two anterior pieces of the specimen kept in the Besson collection and then figured the third piece (posterior portion from the Faujas de Saint-Fond collection) in 1824 in association with the anterior pieces (Besson collection) and other cranial remains belonging to Metriorhynchidae. The remaining species referred to ''Steneosaurus'' thus require new generic names, and some species have already been assigned to new genera prior to ''Steneosaurus'' being declared a ''nomen dubium''. Species in this genus are traditionally classed into two skull groups: longirostrine (long, narrow jaws) and mesorostrine (slightly shorter jaws). ;Longirostrine * S.' atelestatus'' - Oxfordian Marnes de Villers of France * S.' blumembachi'' - Oxfordian Marnes de Villers of France * S.' oplites'' - Toarcian La Caine-Curcy of France * S.' rudis'' - France Additional ''Steneosaurus'' fossils not attributed to a specific genus have been found in: * Bathonian

El Mers Formation The El Mers Group is a geological group in the Middle Atlas of Morocco. It is subdivided into 3 formations named the El Mers 1, 2 and 3 Formations respectively. It is a marine deposit primarily consisting of marl, with gypsum present in the upper ...

, Morocco * Bathonian Techout Formation, Tunisia * Jurassic

Czarnogłowy Czarnogłowy (formerly german: Zarnglaff) is a village in the administrative district of Gmina Przybiernów, within Goleniów County, West Pomeranian Voivodeship, in north-western Poland. It lies approximately east of Przybiernów, north of Gol ...

, Poland

Reassigned species

* Steneosaurus' baroni'' = '' Andrianavoay'' * Steneosaurus' bollensis'' = '' Macrospondylus'' * S.' bouchardi'' - = '' Proexochokefalos'' * Steneosaurus' boutilieri'' = '' Yvridiosuchus'' * Steneosaurus' brevior'' = '' Mystriosaurus'' * Steneosaurus' deslongchampsianus'' * Steneosaurus' edwardsi'' = '' Neosteneosaurus'' * Steneosaurus' gracilirostris'' = '' Plagiophthalmosuchus'' * Steneosaurus' heberti'' = '' Proexochokefalos'' * Steneosaurus' larteti'' = '' Deslongchampsina'' * Steneosaurus' leedsi'' = '' Charitomenosuchus'' * Steneosaurus' megarhinus'' = ''

Bathysuchus ''Bathysuchus'' ("deep water crocodile") is an extinct genus of teleosaurid thalattosuchian from Late Jurassic (Kimmeridgian) deep water marine deposits in England and France. ''Bathysuchus'' displays features that suggest it was more pelagic t ...

'' * Steneosaurus' megistorhynchus'' = ''

Seldsienean ''Seldsienean'' (Old English for "seldom seen one") in an extinct genus of machimosaurid thalattosuchian from the Middle Jurassic of England and France. It is known from the Calcaire de Caen and the Cornbrash Formation. Its type species In ...

'' * Steneosaurus' obtusidens'' = ''

Lemmysuchus ''Lemmysuchus'' is a genus of machimosaurid thalattosuchian from the Middle Jurassic Callovian of England and France. Like many other teleosauroids from Europe, it has had a convoluted taxonomic history. History ''"Steneosaurus" obtusidens'' ...

Classification

A 2005

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis into the evolutionary relationships of

Thalattosuchia Thalattosuchia is a clade of marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution. They are colloquially referred to as marine crocodiles or sea crocodiles, though they are not members of C ...

did not support the

monophyly In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...

of ''Steneosaurus'', as the genera ''

Machimosaurus ''Machimosaurus'' is an extinct genus of machimosaurid crocodyliform from the Late Jurassic (Kimmeridgian and Tithonian) and Early Cretaceous. The type species, ''Machimosaurus hugii'', was found in Switzerland. Other fossils have been found i ...

'' and ''

Teleosaurus ''Teleosaurus'' (from el, τέλειος , 'perfect' and el, σαῦρος , 'lizard') is an extinct genus of teleosaurid crocodyliform found in the Middle Jurassic Calcaire de Caen Formation of France. It was approximately in length and we ...

'' both fell within ''Steneosaurus''. Reinforcing the paraphyly of ''Steneosaurus'', the Callovian species ''"Steneosaurus" obtusidens'' has been recovered as the sister species of ''Machimosaurus'' in recent cladistic analyses of Thalattosuchia and renamed ''

'', while Steneosaurus' bollensis'' was recovered in a basal position to other members of ''Steneosaurus sensu lato''.

References

External links

Angellis Net pdf
{{Taxonbar, from=Q137074 Thalattosuchians Prehistoric pseudosuchian genera Prehistoric marine crocodylomorphs Early Jurassic crocodylomorphs Middle Jurassic crocodylomorphs Aalenian life Bajocian life Bathonian life Callovian life Toarcian life Early Jurassic reptiles of Europe Middle Jurassic reptiles of Europe Fossils of England Oxford Clay Fossils of France Fossils of Germany Solnhofen fauna Jurassic reptiles of Africa Fossils of Morocco Fossils of Tunisia Fossil taxa described in 1825 Nomina dubia

Discovery and assigned species

Reassigned species

Classification

See also

References

External links