''Saurosphargis'' is an extinct

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 nom ...

of a basal marine reptile, saurosphargid, known 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 ...

(

Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic ...

age) of southwestern

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populou ...

and eastern

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

. It contains a single species, ''Saurosphargis volzi''.

Discovery

''Saurosphargis'' is known solely from the unnumbered

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

that was housed at the Breslaw Museum, a partial

postcranial Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated s ...

skeleton that included a section of 12 incomplete back vertebrae with ribs. The specimen collected at Gogolin, Gorny Slask of

Upper Silesia Upper Silesia ( pl, Górny Śląsk; szl, Gůrny Ślůnsk, Gōrny Ślōnsk; cs, Horní Slezsko; german: Oberschlesien; Silesian German: ; la, Silesia Superior) is the southeastern part of the historical and geographical region of Silesia, locate ...

, from the Chorzower Schichten horizon of the Lower Muschelkalk, dating to the early

stage of the early

, about 246

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago) ...

. Rieppel (1995) described an isolated

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...

MGU Wr. 3873s housed at Institute of Geological Sciences, University of Wroclaw, that is possibly referable to ''Saurosphargis'', collected from the same general location. The holotype was destroyed during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

, and as a result many authors considered ''Saurosphargis'' to be a '' nomen dubium'' prior to the discovery of additional saurosphargid species, that enabled better comparisons with the detailed descriptions and figures of ''Saurosphargis'' in Huene (1936). Paul Albers and Li ''et al.'' (2011) briefly reported the discovery of well-preserved material referable to ''Saurosphargis'' from the Lower Muschelkalk of

Winterswijk Winterswijk (; also known as ''Winterswiek'' or ''Wenters'') is a municipality and a town in the eastern Netherlands. It has a population of and is situated in the Achterhoek, which lies in the easternmost part of the province of Gelderland in th ...

. The material is currently under preparation.

Etymology

''Saurosphargis'' was officially named by Friedrich von Huene in

1936 Events January–February * January 20 – George V of the United Kingdom and the British Dominions and Emperor of India, dies at his Sandringham Estate. The Prince of Wales succeeds to the throne of the United Kingdom as King E ...

and 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 specime ...

is ''Saurosphargis volzi''. The generic name is derived from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''sauros'', "lizard", and ''sphargis'', the old genus name for the leatherback turtle, in reference to the dorsal

osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinc ...

"body armor" and broadened ribs forming a closed chest rib basket, traits that are seemingly transitional between

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...

s and other reptiles. The specific name ''volzi'' honors the paleontologist Wilhelm Volz who found and briefly described the holotype of ''Saurosphargis'' and the Lower Muschelkalk of Gogolin between 1903 and 1908.

Phylogeny

The following

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

is simplified after Li ''et al.'' (2014)

phylogenetic analysis 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 ...

, showing interrelationships of all known

Saurosphargidae Saurosphargidae is an extinct family of marine reptiles known from the early Middle Triassic (Anisian stage) of Europe and China. The type species of the family is '' Saurosphargis volzi'', named by Friedrich von Huene in 1936 based on a single ...

species, and the placement of the clade within

Sauria Sauria is the clade containing the most recent common ancestor of archosaurs (such as crocodilians, dinosaurs, etc.) and lepidosaurs ( lizards and kin), and all its descendants. Since most molecular phylogenies recover turtles as more closely ...

. ''Saurosphargis'' was coded solely based on the holotype. The removal / inclusion of

Ichthyopterygia Ichthyopterygia ("fish flippers") was a designation introduced by Sir Richard Owen in 1840 to designate the Jurassic ichthyosaurs that were known at the time, but the term is now used more often for both true Ichthyosauria and their more primitiv ...

was found to affect the

topology In mathematics, topology (from the Greek words , and ) is concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing ...

the most - switching the positions of the ''Eusaurosphargis''+''Helveticosaurus'' and Thalattosauriformes clades, and altering the positions of several taxa within Eosauropterygia, which are not shown.

References

Fossil taxa described in 1936 Middle Triassic reptiles of Europe Anisian life Prehistoric reptile genera {{triassic-reptile-stub