''Saltopus'' ("hopping foot") is a genus of very small bipedal dinosauriform containing the single

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

''Saltopus elginensis'' from the late

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

period of

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

. It is one of the most famous Elgin Reptiles.

Description

''Saltopus elginensis'' is known only from a single partial skeleton lacking the skull, but including parts of the vertebral column, the forelimbs, the pelvis and the hindlimbs. These have been mainly preserved as impressions or natural casts in the sandstone; very little bone material is present.Huene, F.R. von (1910). "Ein primitiver Dinosaurier aus der mittleren Trias von Elgin." ''Geol. Pal. Abh. n. s.'', 8: 315-322. It was about the size of a domestic cat, and would have been roughly long. It had hollow bones like those of birds and other dinosaurs. It may have weighed around . In 2016, it was estimated to be 50 cm long, 15 cm high at the hips, and 110 g. Most of the length was accounted for by the tail. It had five-fingered hands, with the fourth and fifth finger reduced in size. Contrary to the original description, in 2011 it was established that the

sacrum The sacrum (: sacra or sacrums), in human anatomy, is a triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, ...

(hip vertebrae) was made up of two vertebrae, the primitive ancestral condition, not four.

History

The only known

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

of ''Saltopus'' was discovered in 1867 by William Taylor in the Lossiemouth West & East Quarries. It was initially named as a specimen of ''Telerpeton elginense'' (now '' Leptopleuron lacertinum'') by Thomas Henry Huxley in 1867, and it was later named and described by Friedrich von Huene in 1910 as 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 ...

''Saltopus elginensis''. The generic name is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''saltare'', "to jump" and Greek πούς, ''pous'', "foot". The specific name refers to its provenance near Elgin, which yields the Elgin Reptiles. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

NHMUK R.3915, was excavated from the Lossiemouth Sandstone Formation dating from the

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227.3 ...

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

stage.

Classification

''Saltopus'' has been variously identified as a saurischian (lizard-hipped) dinosaur, a more advanced

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

, and a close relative of the herrerasaurs, but its

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

has been in dispute because only fragmentary remains have been recovered. Some researchers, such as

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

,Paul, G.S. (1988). ''Predatory Dinosaurs of the World.'' New York: Simon and Schuster. 464 pp. have suggested it may represent a juvenile specimen of a

coelophysid Coelophysoidea is an extinct clade of theropod dinosaurs common during the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivore, carnivorous fo ...

theropod such as ''

Coelophysis ''Coelophysis'' ( Traditional English pronunciation of Latin, traditionally; or , as heard more commonly in recent decades) is a genus of coelophysid Theropoda, theropod dinosaur that lived Approximation, approximately 215 to 201.4 million y ...

'' or ''

Procompsognathus ''Procompsognathus'' is an extinct genus of Coelophysidae, coelophysid Theropoda, theropod dinosaur that lived approximately 210 million years ago during the later part of the Triassic Period (geology), Period, in what is now Germany. ''Procomp ...

''. Rauhut and Hungerbühler in 2000 concluded it is a primitive dinosauriform, not a true dinosaur, closely related to '' Lagosuchus''.Rauhut, O.M.W. and A. Hungerbühler. (2000). "A review of European Triassic theropods." ''Gaia'', 15: 75-88.

Michael Benton Michael James Benton (born 8 April 1956) is a British palaeontologist, and professor of vertebrate paleontology, vertebrate palaeontology in the School of Earth Sciences at the University of Bristol. His published work has mostly concentrated on ...

, continuing the studies of the late Alick Walker redescribing the fossil in 2011, found it to be a dinosauriform more derived than '' Lagosuchus''.Michael J. Benton and Alick D. Walker†. 2011. "''Saltopus'', a dinosauriform from the Upper Triassic of Scotland", ''Earth and Environmental Science Transactions of the Royal Society of Edinburgh'', Volume 101, Special Issue 3-4, pp 285 - 299 Royal Society of Edinburgh 2011. Published online: 17 May 2011 A large phylogenetic analysis of early dinosaurs and dinosauromorphs by Matthew Baron, David B. Norman and Paul Barrett (2017) recovered ''Saltopus'' near the base of the dinosaur lineage, suggesting that it may represent the closest relative of true dinosaurs.Baron, M.G., Norman, D.B., and Barrett, P.M. (2017). A new hypothesis of dinosaur relationships and early dinosaur evolution. ''Nature'', 543: 501–506.

References

External links

A photograph of the sandstone slab showing the only known ''Saltopus'' specimen, published by the twitter account of the Barret Lab at the London Natural History Museum

The counterpart of the ''Saltopus'' slab, from the same source
{{Taxonbar, from1=Q132859, from2=Q20719247 Dinosauromorpha Late Triassic reptiles of Europe Triassic Scotland Fossils of Scotland Fossil taxa described in 1910 Taxa named by Friedrich von Huene 1910 in Scotland History of Moray