Chindesaurus ‭(‬Chinde lizard‭)

Short Info

Chindesaurus ‭(‬Chinde lizard‭)

Phonetic : Chin-de-sore-us.

Named By : R.‭ ‬A.‭ ‬Long & P.‭ ‬A.‭ ‬Murry‭ ‬-‭ ‬1995

Diet : Carnivore

Size : Estimated 2-4 meters long

Type of Dinosaur : Small Theropod

Type Species : C.‭ ‬bryansmalli‭ (‬type‭)

Found in : USA,‭ ‬Arizona‭ ‬-‭ ‬Chinle Formation,‭ ‬New Mexico‭ ‬-‭ ‬Bull Canyon Formation,‭ ‬Chinle Formation,‭ ‬Texas‭ ‬-‭ ‬Colorado City Formation

When it Lived : Late Triassic, 227-210 million years ago

Chindesaurus (/,tSIndI’so:r@sCHIN-di SAWR-@s) was an extinct genus from the basal saurischian dinosaurs that was found in the Late Triassic (213-210 million years ago) of the southwest United States. It is recognized as one specie, C. bryansmalli, that is derived from a skeleton fragment found in Petrified Forest National Park in Arizona. The specimen that was originally discovered was dubbed “Gertie”, and generated plenty of attention for the park after its discovery in 1984 , and airlifted out of Park in the year 1985. Other fragmentary specimens with referred names were found throughout Late Triassic sediments throughout Arizona, New Mexico, and Texas however, they may not be part of the Genus. Chindesaurus was an animal that was bipedal that was approximately twice as big as the Wolf.

Chindesaurus skeleton
Maurissauro, CC BY-SA 4.0, via Wikimedia Commons

Chindesaurus’s classification has been debated and several papers have reached different opinions on its affinity. The fossils of Chindesaurus were initially considered to belong to “prosauropods” (basal sauropodomorphs) however, its initial description as well as subsequent studies have suggested Chindesaurus was actually a herrerasaurid herrerasaurian. A redescription in 2019 of its Holotype was deemed by Chindesaurus as a theropod that was closely related to Tawa, a less sized dinosaur that was discovered in The Hayden Quarry of Ghost Ranch, New Mexico.

Many specimens have been identified as Chindesaurus but only one specimen contains enough evidence to stay within the genus in certainty. The specimen, called holotype PEFO 1095, is a part of a Skeleton that was discovered in Petrified Forest National Park in Apache County, Arizona. PEFO 10395 was first discovered around 1984, through Bryan Small, who recovered the bones from an mudstone layer that was blue in the Chinle Formation’s Upper Petrified Forest Member. Based on the U-Pb-based dating of the subordinate units and overlying ones the sedimentary layer of mudstone was laid down around 213 to 213 million years ago, in the Norian stage of the Triassic.

PEFO The majority of PEFO 10395 is composed of limb bones, vertebrae along with hip fractures. Vertebrae comprise a variety of partially cervical (neck) dorsal (back) and the caudal (tail) vertebrae, together and two sacral (hip) vertebrae as well as a chevron and rib fragments. Three bones that make up the hip (the pubis, ilium, and the ischium) are represented by distinct fragments. Leg bones include a fully right femur as well as the upper portion of left femur the right tibia is not fully formed and an astragalus bone in the right side that is located in the lower ankle. A single tooth that is serrated is also thought to be an element of the sample but this could be in error.

After the specimen of a holotype was found the specimen was dubbed “Gertie” (after Gertie the Dinosaur) and garnered a lot of publicity. “Gertie” was subsequently airlifted by helicopter on June 6, 1985 and then transferred into the University of California Museum of Paleontology (UCMP) in Berkley, CA, where it was developed over the following years. It is the anniversary date of this airlift as well as the media attention it generated to Petrified Forest National Park is held at the park each year. “Gertie” was described and named a proper binomial in 1995 by R.A. Long and P.A. Murry in 1995. It was initially referred to by the name of “Chinde Point dinosaur”, due to the geophysical landmark near the location it was rediscovered from. This was later changed to the generic name of the dinosaur which is being derived by it being the Navajo phrase chindi (meaning “ghost” or “evil spirit”) and the Greek word “sauros” (sauros) (meaning “lizard”). The name can be translated to “ghost lizard” or “Lizard from Chinde Point”. The exact name, bryansmalli, honors the creator, Bryan Small.

A number of other incomplete specimens are referred to as the Genus. The specimens are made up of vertebrae and fragments of femurs discovered across all of the American southwest. Eight of these specimens have been stored in PEFO (Petrified Forest National Park AZ) in Arizona, which was where the Holotype first discovered. Two of them are at the UCMP (University of the California Museum of Palaeontology) which is which is where the holotype was made. A further six are in the New Mexico Museum of Natural History and Science (NMMNH) located in Albuquerque, NM, with at the very least some were discovered inside the Bull Canyon Formation of New Mexico. An entire femur GR 226, was discovered in 2006 in the Hayden Quarry of Ghost Ranch, NM, where it is currently stored.

While the majority of the specimens called Chindesaurus originate from the Norian-age formations in Arizona as well as New Mexico, there are some exceptions: TMM 31100-523 which is comprised of a proximal bone femur was found in the Carnian-age Colorado City Formation of Texas. It is in the collection from the Texas Memorial Museum in Austin, TX. Another similar case is UMMP 870, a fragment of Ilium that was first reported in 1927. It was found in the carnian? age Tecovas Formation from Texas which is currently housed within the University of Michigan (UMMP) in Ann Arbor, MI. But, UMMP could be a distinct species of the early dinosaurs, Caseosaurus crosbyensis. The referenced Texas fossils from Chindesaurus were previously thought to have been the most ancient dinosaur remains discovered in the world.

Although specimens that are referred to as Chindesaurus are widespread and are sometimes preserved well however none of them display specific features that belong to Chindesaurus as a species. The connection to Chindesaurus of two species (NMMNH P16656 as well as NMMNH P17325) to Chindesaurus was questioned in 2007. Marsh et al. (2019) asserted in 2019 that just the specimen of the holotype from Chindesaurus is worthy of belonging to the Genus. They have removed all specimens, apart from the holotype specimen from the genus, and reclassified the rest of them as indeterminate materials of Chindesaurus + Tawa. Chindesaurus + Tawa Clade that they studied.

Long & Murry reconstructed Chindesaurus with a strong body and legs that are long as well as a rather long neck and an estimated length of 3-4 metres (9.9 up to 13.1 feet). [33 Benson & Brusatte (2012) claimed that Chindesaurus was shorter, from up two to 2.3 meters (6.6 to 7.5 feet) to length. Holtz (2012) found that Chindesaurus was around two meters (6.6) feet, with the weight was comparable to the weight of an Wolf (23-45 kg, or around 50-100 lbs). The structure of the skeleton of Chindesaurus isn’t fully understood therefore these full body measurements are only rough estimates. The holotype specimen could not fully developed because of its non-fused neurocentral sutures in the ankle and dorsal. But, these characteristics may not be completely correlated with the development of early dinosaurs, and the specimen is also characterized by other features that indicate a post-juvenile phase including an elongated trochanteric shelf, as well as the caudal neurocentral sutures that are fused.

Source: Wikipedia