''Eurycleidus'' is an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
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 no ...
of large-bodied
rhomaleosaurid known from the
Early Jurassic
The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma&nb ...
period
Period may refer to:
Common uses
* Era, a length or span of time
* Full stop (or period), a punctuation mark
Arts, entertainment, and media
* Period (music), a concept in musical composition
* Periodic sentence (or rhetorical period), a concept ...
(most likely earliest
Hettangian
The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triassic ...
stage) of the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and No ...
. It contains a single species, ''E. arcuatus''.
[ Like other plesiosaurs, ''Eurycleidus'' probably lived on a diet of fish, using its sharp needle-like teeth to catch prey. Its shoulder bones were fairly large, indicating a powerful forward stroke for fast swimming.
]
Phylogeny
Most 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 ...
analyses find the type species of the genus, ''Eurycleidus arcuatus'', to be a relatively basal rhomaleosaurid. A second species, ''E. megacephalus'' (Stutchbury, 1846 riginally_''Rhomaleosaurus_megacephalus''.html" ;"title="Rhomaleosaurus.html" ;"title="riginally ''Rhomaleosaurus">riginally ''Rhomaleosaurus megacephalus''">Rhomaleosaurus.html" ;"title="riginally ''Rhomaleosaurus">riginally ''Rhomaleosaurus megacephalus'', was reassigned to this genus by Smith (2007).[ However, most analyses find ''E. megacephalus'' to represent an unnamed genus, which is distinct from both ''Eurycleidus'' and ''Rhomaleosaurus''.] ''E. megacephalus'' was moved to its own genus ''Atychodracon'' by Adam Smith in 2015.
The cladogram below shows ''E. arcuatus'' phylogenetic position among other plesiosaurs following Benson ''et al.'' (2012).
See also
* Timeline of plesiosaur research
This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished du ...
* List of plesiosaurs
This list of plesiosaurs is a comprehensive listing of all genera that have ever been included in the order Plesiosauria, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered inv ...
References
{{Taxonbar, from=Q3616157
Rhomaleosaurids
Early Jurassic plesiosaurs of Europe
Fossil taxa described in 1922
Taxa named by Charles William Andrews
Sauropterygian genera