Pronunciation: see-SER-no-SOR-us
Meaning: Separated lizard
Author/s: Brett-Surman (1979)
Synonyms: Kritosaurus australis
First Discovery: Chubut, Argentina
Discovery Chart Position: #269
Secernosaurus koerneri
Secernosaurus is a species of hadrosaurid, specifically a kritosaurinin saurolophine hadrosaurid, found in the Late Cretaceous Bajo Barreal Formation of Argentina. When described in 1979, it was the loneliest hadrosaurid too, living in South America (part of the northern supercontinent of Gondwana during the Mesozoic) while all of its closest relatives were in North America, Europe or Asia (the southern supercontinent of Laurasia during the Mesozoic), and it's this separation that prompted the name, meaning separated lizard, from the Latin "secerno".
At one point, Secernosaurus had the company of another separated lizard, Kritosaurus australis ("kritos" also means separated, but in Greek rather than Latin, and in this case refers to its disjointed fossils), until the latter turned out to be synonymous with the former. But there is some good news. In the early part of the 21st century, palaeontologists discovered two more Late Cretaceous South American hadrosaurids in Willinakaqe and Lapampasaurus, although they're all from different Provinces and there's no evidence to suggest they gathered socially.
Hadrosaurid remains are pretty rare in the Late Cretaceous Formations of South America, while sauropods are many and varied, suggesting the latter were the dominant herbivores. In North America, that situation is topsy-turvy.
At one point, Secernosaurus had the company of another separated lizard, Kritosaurus australis ("kritos" also means separated, but in Greek rather than Latin, and in this case refers to its disjointed fossils), until the latter turned out to be synonymous with the former. But there is some good news. In the early part of the 21st century, palaeontologists discovered two more Late Cretaceous South American hadrosaurids in Willinakaqe and Lapampasaurus, although they're all from different Provinces and there's no evidence to suggest they gathered socially.
Hadrosaurid remains are pretty rare in the Late Cretaceous Formations of South America, while sauropods are many and varied, suggesting the latter were the dominant herbivores. In North America, that situation is topsy-turvy.
(Koerner's separated lizard)Etymology
Secernosaurus is derived from the Latin "secerno" (sever, separate) and the Greek "sauros" (lizard), referring to the fact that this Gondwanan hadrosaurid was geographically severed from its Laurasian relatives.
The species epithet, koerneri, honors Dr. Harols E. Koerner, a professor at the University of Colorado.
Discovery
The remains of Secernosaurus were discovered at Lago Colhue Huapi in the "upper member" of the Bajo Barreal Formation (formerly "Laguna Palacios" in the San Jorge Formation), Rio Chico, Chubut, Argentina, and collected in 1923 by an expedition from The Field Museum (Chicago, IL) led by J. B.
Abbott. The holotype (FMNH PR 13423) consists of a couple of vertebrae, some arm bones, a shoulder blade, a shin bone, bits of pelvis and a partial braincase.Discovered in 1923 but not indentified until 1979, Secernosaurus was the first hadrosaurid to be found in the southern hemisphere.
