''Strongylosteus'' is an extinct

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 prehistoric

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 ...

that lived during the early

Toarcian The Toarcian is, in the International Commission on Stratigraphy, ICS' geologic timescale, an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic. It spans the time between 184.2 Megaannum, Ma (million ...

age of the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic� ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

.Hennig, E. (1925). ''Chondrosteus Hindenburgi'' Pomp.---Ein «Stör» des württembergischen Ölschiefers (Lias\epsilon). Palaeontographica (1846-1933), 115–134. Its

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 ...

is ''Strongylosteus hindenburgi'' (

monotypy In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

). It is related to modern

sturgeon Sturgeon (from Old English ultimately from Proto-Indo-European language, Proto-Indo-European *''str̥(Hx)yón''-) is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the ...

and

paddlefish Paddlefish (family Polyodontidae) are a family of ray-finned fish belonging to order Acipenseriformes, and one of two living groups of the order alongside sturgeons (Acipenseridae). They are distinguished from other fish by their elongated rost ...

(

Acipenseroidei Acipenseriformes is an order of basal ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct families Chondrosteidae and Peipiaosteidae. They are the second earliest diverging ...

Discovery

''Strongylosteus hindenburgi'' is known from the Toarcian Posidonienschiefer Formation in southwestern Germany, specifically around

Holzmaden Holzmaden is a town in Baden-Württemberg, Germany that lies between Stuttgart and Ulm. Holzmaden is 4 km south-east from Kirchheim unter Teck and 19 km south-east of Esslingen am Neckar. The A 8 runs south from Holzmaden. The town a ...

and

Dotternhausen Dotternhausen is a municipality in the Zollernalbkreis district, in Baden-Württemberg, Germany. History Dotternhausen became a possession of the Kingdom of Württemberg in 1805 and was assigned to . In 1810, it was reassigned to and then to in ...

. Initially identified by Pompeckj in 1914 as "'' Chondrosteus'' ''hindenburgi''", hovewer the name was never formally published. Hauff (1921) mentioned it as a ''

nomen nudum In Taxonomy (biology), taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published ...

'', and Hennig (1925) provided the first formal description, retaining the name but describing it in detail alongside additional specimens. Jaekel (1929) later reassigned it to the new genus ''Strongylosteus'', correcting its taxonomic position. Since the 1925 description, over a dozen specimens, including isolated bones and partial skeletons, have been noted in various museum collections, though many remain undescribed or misidentified. This include a juvenile specimen under one meter long, present in the Urwelt Museum Hauff, awaiting formal study that may reveal ontogenic shifts.

Synonym with other Genera

''Strongylosteus'' has been suggested as a junior synonym of '' Chondrosteus'', although there haven't been any new revisions about the status of the genus. There have also been suggestions of synonymy between ''Strongylosteus hindenburgi'' and '' Gyrosteus'' ''mirabilis'', mainly due to incomplete descriptions and preservation issues. However, a 2025 analysis of a new skull roof from the Toarcian

Whitby Mudstone The Whitby Mudstone is a Toarcian (Early Jurassic; ''Falciferum''-''Bifrons'' in regional chronostratigraphy) geological formation in Yorkshire and Worcestershire, England. ''Strongylosteus'' was a large member of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Chondrosteidae Chondrosteidae is a family (biology), family of extinct marine actinopterygian fishes, known from the Early Jurassic of Europe. They are closely related to modern Sturgeon, sturgeons and paddlefish of the order Acipenseriformes, and are either ...

and the largest non-reptilian marine

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

in the

Posidonia Shale The Posidonia Shale (, also called Schistes Bitumineux in Luxembourg) geologically known as the Sachrang Formation, is an Early Jurassic (Early to Late Toarcian) geological formation in Germany, northern Switzerland, northwestern Austria, souther ...

, with the largest articulated specimen (SMNS 7790) measuring 3.2 m in total length.

References

External links

* Early Jurassic fish Acipenseriformes {{Jurassic-fish-stub

Discovery

Synonym with other Genera

See also

References

External links