Eolambia ‭(‬Dawn Lambe‭ ‬-‭ ‬after the palaeontologist Lawrence Lambe‭)

Short Info

Eolambia ‭(‬Dawn Lambe‭ ‬-‭ ‬after the palaeontologist Lawrence Lambe‭)

Phonetic : E-oh-lam-be-ah.

Named By : James Kirkland‭ ‬-‭ ‬1998

Diet : Herbivore

Size : Estimated 6 – 9 meters long

Type of Dinosaur : Large Theropod

Type Species :E.‭ ‬caroljonesa‭ (‬type‭)

Found in : USA,‭ ‬Utah‭ ‬-‭ ‬Cedar Mountain Formation,‭ ‬Mussentuchit Member

When it Lived : Late Cretaceous, 99-94 million years ago

Eolambia, which means “dawn Lambeosaurine”, is a genus consisting of herbivorous dinosaurs. It dates back to the late Late Cretaceous in the United States. It only contains E. caroljonesa (a single species), which paleontologist James Kirkland named in 1998. Carole and Ramal stumbled upon the type specimen of Eolambia in 1993. The species name is in honor of Carole. There have been hundreds of bones discovered in the skeleton from both juveniles and adults. All specimens were found in Emery County in Utah in the Mussentuchit Member, Cedar Mountain Formation.

EolambiaLukas Panzarin and Andrew T. McDonald, CC BY 2.5, via Wikimedia Commons

Eolambia, which measures 6 meters (20 feet) in length, is a large member its group. It is similar to the Asian hadrosauroids Equijubus and Probactrosaurus in terms of skull, vertebrae and limbs. However, it could be closer to the North American Protohadros. Based on the straightness and shape of the quadrate bone, this group would be considered an isolated, endemic radiation from hadrosauroids. Although it resembled hadrosaurids, lambeosaurine and scapula hadrosaurids, many features led to its identification as one of them. However, these similarities were rejected as being either completely convergent, or misinterpreted.

Eolambia dentaryAndrew T. McDonald, John Bird, James I. Kirkland, Peter Dodson, CC BY 2.5, via Wikimedia Commons

Eolambia lived in a forest environment near the lakes’ edges in a humid floodplain environment. She ate gymnosperms and ferns as well as flowering plants. The lakes’ water levels changed with the cyclical dry and wet spells caused by precession of Earth. These changes were reflected in the alternating bands in sediments from the Mussentuchit Member. Eolambia was a young juvenile and would have been preyed on by large crocodylomorphs that lived in the lake water. As they grew older, however, Eolambia became more resistant to the crocodylomorphs and mature theropods like the Siats neovenatorid were able to prey on them.

Lambeosaurus ROMRobin Zebrowski, CC BY 2.0, via Wikimedia Commons

Peter Galton and James A. Jensen, both from Utah, described in 1979 a fragmentary right-femur (BYU 2000) that belonged to a hadrosaurian dinosaur. It was found in sediments of the Cedar Mountain Formation, Arches National Park. Although it was poor material, it was crucial for it to be the first specimen of a hadrosaur from the Lower Cretaceous anywhere on the planet. Jensen and Galton speculated that more complete remains may be discovered from this formation. Several hadrosauroid teeth were also found in small vertebrates quarries in the San Rafael Swell’s western region, near Castle Dale, Emery County, Utah. They were first described by J. Michael Parrish in 1991. Carole Jones and Ramal Jones found fragmentary bones at a fossil site in the Swell’s northwestern region in 1993. Donald Burge (director of the College of Eastern Utah Prehistoric Museum, CEUM) was alerted to the location. In Carol’s honour, the site, which was previously known as CEUM Locality42em366v, was named Carol’s Site (sic). The fossils are part of an adult hadrosauroid and include parts of the skull, leg, vertebrae, ischium, as well as the vertebrae. CEUM 5212 was a partial skull from an adult. It was also found in CEUM Locality42em369v. CEUM 8786 was a left femur taken from an adult and discovered later on Carol’s Site. It was not described until 2012.

The Oklahoma Museum of Natural History (OMNH), had also found remains from the same hadrosauroid during excavations in the southwestern part of the Swell. The OMNH first discovered six specimens. These included two juvenile skeletons that contained vertebrae, an ulna and ischium. A partial juvenile skeleton which included parts of the skull and forelimbs. Further discoveries were made by the OMNH in different quarries of the hadrosauroid’s teeth. James Kirkland was able to examine the specimens collected by Richard Cifelli, OMNH. Kirkland continued to preliminarily write about the specimens at the 1994 Society of Vertebrate Paleontology conference abstract.

Kirkland officially named the specimens Eolambia caroljonesa in a 1998 paper that was published in Bulletin of New Mexico Museum of Natural History and Science. The combination of the Greek prefixes eos/eos (“dawn”, meaning “morning”, and the suffix lambia (derived form Lambeosaurus which is named after Canadian paleontologist Lawrence Lambe) creates the generic name. The genus name is “dawn or early lambeosaurine” in reference to the presumed position of the most basal Lambeosaurine. Carole Jones is the name of the genus. Michael Skrepnick, a paleoartist, suggested the name Eolambia. It replaced the informal “Eohadrosaurus Caroljonesi” that Kirkland used before 1998. The ICZN incorrectly uses the epithet caroljonesa. In this instance, caroljonesae would be the correct spelling.

Eolambia, a large hadrosauroid, is its name. Initial estimates put the skull’s length at 1 meter (3 feet 3 inches). However, this was due to an unusually long nose that was later corrected with additional material. Gregory S. Paul in 2016 estimated that Eolambia had a body length 6 meters (20 feet) and a weight 1 metric tons (0.98 long tonnes; 1.1 short tons). This is consistent with Thomas R. Holtz Jr.’s 2012 body length estimate of 6.9 meters (20ft). In 2008, an adult specimen had a length estimate of 5.2 metres (17 ft) with a height at its hip of 2 meters (6 feet 7 in).

Source: Wikipedia