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

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of teleosaurid

crocodyliform Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ...

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 ...

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 ...

(

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 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 located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. 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 purpose of classifying organisms that do not fit anywhere else. They are typically defined by e ...

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 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 ...

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

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

Discovery and assigned species

The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

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

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

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 (1741-1819), 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

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 ''Plagiophthalmosuchus'' is a genus of teleosauroid, known form the Early Jurassic (Early Toarcian) Whitby Mudstone Formation of Whitby, Yorkshire, UK, and Dudelange, Luxembourg. The type species, ''P. gracilirostris'', was originally named as ...

'' * Steneosaurus' heberti'' = '' Proexochokefalos'' * Steneosaurus' larteti'' = '' Deslongchampsina'' * Steneosaurus' leedsi'' = ''

Charitomenosuchus ''Charitomenosuchus'' (meaning "graceful crocodile") is an extinct genus of machimosaurid teleosauroid from the Callovian Oxford Clay Formation of England England is a Countries of the United Kingdom, country that is part of the United ...

'' * Steneosaurus' megarhinus'' = '' Bathysuchus'' * Steneosaurus' megistorhynchus'' = '' Seldsienean'' * Steneosaurus' obtusidens'' = '' Lemmysuchus''

Classification

A 2005

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis into the evolutionary relationships of

Thalattosuchia Thalattosuchia is a clade of mostly 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 member ...

did not support the

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

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 in ...

'' and ''

Teleosaurus ''Teleosaurus'' (from , 'perfect' and , 'lizard') is an extinct genus of teleosaurid crocodyliform found in the Middle Jurassic Calcaire de Caen Formation of France. It was approximately in length. The holotype is MNHN AC 8746, a quarter of ...

'' 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 '' Lemmysuchus'', 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 Thalattosuchia 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