''Erquelinnesia'' is an extinct

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

genus from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

period, which has been found in

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 ...

s. Paleontologist

Louis Dollo Louis Antoine Marie Joseph Dollo (; 7 December 1857 – 19 April 1931) was a Belgian palaeontologist, known for his work on dinosaurs. He also posited that evolution is not reversible, known as Dollo's law. Together with the Austrian Othenio Ab ...

first described this genus late 19th century from fossilized samples found in the layers of Upper Paleocene / Lower Eocene in Hainaut, Belgium. ''Erquelinnesia'' lived between the Upper Cretaceous (Maastrichtian, about 70.6 million years ago) and Lower Paleocene (Danian, about 61.7 million years ago). Louis Dollo named his discovery as ''Pachyrhynchus gosseleti'' in 1886. However, in the following year, the nomenclature was changed by Dollo to ''Erquelinnesia gosseleti'' to resolve a conflict with another already existing generic name. Moreover, an additional species was attributed to the genus ''Erquelinnesia''. The North American species called ''Erquelinnesia molaria'' that was known only from a fossilized mandible bone has subsequently re-categorized to the genus ''

Euclastes ''Euclastes'' is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope in 1867, and contains three species. ''E. hutchisoni'', was named in 2003 but has since b ...

''. In 2010, new remnants were found in South America. The newly discovered species was from the Paleocene of Argentina; it was given the name ''Erquelinnesia meridionalis''. The species was previously designated to a separate genus, ''Pampaemys'' and then, ''Euclastes'' before the re-classification in light of the newly found fossilized evidence.

Description

This genus of prehistoric sea turtle was similar to the modern sea turtles like ''Dermochelys coriacea'' (leatherback sea turtle); both have reduced carapace and slender bodies. Physically, ''Erquelinnesia'' have very large and prominent triangular skulls and elongated symphysis structures of their mandibles . They also have remarkably long secondary palates. The massive jaws and various specialized structures of the jaws appeared to be ideal for crushing the hard shells of ancient mollusks. ''Erquelinnesia'' exemplified a development of

evolutionary radiation An evolutionary radiation is an increase in taxonomic diversity that is caused by elevated rates of speciation, that may or may not be associated with an increase in morphological disparity. A significantly large and diverse radiation within ...

in ancient sea turtles. They have physiologically developed a skull suitable for crushing shells (

durophagy Durophagy is the eating behavior of animals that consume Seashell, hard-shelled or exoskeleton-bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including ...

). This morphological features survived until the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

period with the discovery of the genus ''

Pacifichelys ''Pacifichelys'' is an extinct genus of sea turtle from the Middle Miocene of Peru (Pisco Formation) and California ( Temblor Formation).

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

based on Lynch and Parham (2003) and Parham and Pyenson (2010):

Bibliography

*Zangerl, R. 1971. Two toxochelyid sea turtles from the Landenian Sands of Erquelinnes (Hainaut) of Belgium. Institut Royal des Sciences Naturelles de Belgique, Memoires 169: 1–32.

References

{{Taxonbar, from=Q15057334 Cheloniidae Prehistoric turtle genera Taxa named by Louis Dollo