Garudimimus ‭(‬Garuda mimic‭)

Short Info

Garudimimus ‭(‬Garuda mimic‭)

Phonetic : Gah-ru-di-mime-us.

Named By : Rinchen Barsbold‭ ‬-‭ ‬1981

Diet : Omnivore

Size : Estimated 3 – 4.7 meters long

Type of Dinosaur : Large Theropod

Type Species : G.‭ ‬brevipes‭ (‬type‭)‬

Found in : Mongolia‭ ‬-‭ ‬Bayan Shireh Formation

When it Lived : Late Cretaceous, 99-89 million years ago

Garudimimus, which means “Garuda mirror”, is an ornithomimosaur genus that lived in Asia during Late Cretaceous. This genus was discovered in 1981 by a Soviet Mongolian paleontological expedition to the Bayan Shireh Formation. Rinchen Barsbold officially described the species in the same year. Although several interpretations were possible regarding the anatomical characteristics of Garudimimus were made during posterior examinations, most were rejected by the comprehensive redescription of 2005. Additional specimens may be found at Garudimimus’ type location.

Garudimimus skeletonJ. Spencer, CC BY 4.0, via Wikimedia Commons

Garudimimus’s only known specimen was a medium-sized creature that measured nearly 3.5m (11ft) in height and weighed around 98kg (216 lb). The Garudimimus was an ornithomimosaur that had a mixture of basal features and derived ones. Its upper and lower jaws were both toothless, which is a characteristic often found in more derived ornithomimids. Garudimimus was a stocky, short-legged hindlimb, with strong feet and a smaller ilia. The foot had four toes, with the first being very small. Ornithomimids had three toes and the first lost. The toothless skull’s jaws are very straight and have a rounded tip. It was thought that the primitive ornithomimosaurian had a lacrimal “horn”, at the top, just before the eye socket. The redescription of one specimen revealed that this structure was actually the left prefrontal bone. An arctometatarsalian condition was also used to reconstruct the metatarsus.

Garudimimus, a primitive ornithomimosaurian in its own family, was first described in 1981. However, with the description of new specimens of Deinocheirus in 2014, it was found that the latter was the sister taxon of Garudimimus, grouping within the Deinocheiridae–ornithomimosaurs not adapted for running or agile movements. This placement was also found to be unlikely. Garudimimus’ pelvic girdle, and hindlimbs show that the musculature in the legs of Garudimimus was less developed than the fast-running Ornithomimids. This indicates poor cursorial abilities. Garudimimus, like other Ornithomimosauria members, was an Omnivore/Herbivore that had a lower bite force. This was compensated for by a horny facial beak.

Based on the holotype specimen, Garudimimus is thought to have stood approximately 3.5m (11ft) and weighed in at 98kg (216lb). The presence of several unfused vertebrae suggests that the holotype was likely to have been a sub-adult still growing animal. This taxon has several distinctive traits, including a jaw articulation that is more backwards than its postorbital bars (arched bone around orbit), depressions at the top of the supraoccipital at back of skull, paired depressions at the lateral surfaces the neural spines anterior caudal vertebrae and a deep groove at upper end of the lateral surface of the pedal phalanges I-1 and II (first and second respectively) of the third digit of your foot.

Based on feather impressions from several Ornithomimus specimens, Garudimimus most likely developed a shaggy feathering that is similar to large paleognath birds like ratites.

The Soviet-Mongolian Paleontological Expedition to the Gobi Desert in 1981 saw the discovery of a small theropod skull by Bayshi Tsav, an expedition from the Late Cretaceous Bayan Shireh Formation. It was located in Southeastern Mongolia. They are now known as MPC-D100/13 (Mongolian Palaeontological Center; originally GIN100/13) and they represent a complete and articulated skeleton. The holotype for the genus Garudimimus species brevipes was also described in Mongolian paleontologist Rinchen Barrsbold. Garudimimus is a combination of Garuda, the legendary winged creatures of Mongolian Buddhist mythology, and Latin mimus (meaning mimic). Latin brevis (meaning shorter) and pes, meaning foot, refer to the specific name. Barsbold identified Garudimimus to be an ornithomimosaurian taxon, but noted that it was more primitive then ornithomimids. He gave Garudimimidae its own family. Barsbold also described the holotype specimen with Halszka Olsmolska in 1983.

The holotype includes the entire skull, 8 cervical vertebrae including the atlas or axis, 9 dorsal verbrae, 6 sacral and 4 caudal spinebrae. There are also some ribs and both ilia.

Gregory S. Paul, a North American author, illustrated Garudimimus in 1988 with a prominent nose horn that was unlike any other ornithomimosaur. He considered this feature to be actually preserved. Dale Alan Russell and Philip J. Currie also gave another interpretation of the holotype’s metatarsus in 1988. and reconstructed it with an arctometatarsal–a condition where the upper end of the third metatarsal is narrowed between the surrounding metatarsals–structure. Thomas R. Holtz, 1992, agreed with this interpretation. He suggested that the metatarsus could be arctometatarsalian. The metatarsus was only disarticulated because it was preserved. Currie and David A. Eberth supported an arctometatarsalian state in 1993. They claimed that part the Archaeornithomimus material (an ornithomimosaur form the nearby Iren Dabasu Formation), belonged to Garudimimus. This was based on the assumed condition of arctometatarsalian, the presence of vestigial number I, and the proportions for metatarsals II-III and IV. They noted that metatarsals III and IV are separated from the extensor metatarsus surface. Holtz, 1994, suggested that there were some similarities in the metatarsus between Garudimimus’s and Chirostenotes’s.

Bernardino P. PerezMoreno and colleagues in 1994 described the primitive ornithomimosaur Pelecanimimus. They also identified the presence a crest within the holotype specimen. Garudimimus was also claimed to have a similar trait, which they described as a nasal horn. Many of the statements made before 2005 were discredited in a thorough redescription by Yoshitsugu Kbayashi and Barsbold. The supposed orbital horn is actually the disarticulated left prefrontal bone and verified that the metatarsus did not suffer taphonomical (changes during decay and fossilisation) distortion and is non-arctometatarsalian. Kobayashi also previously demonstrated that the metatarsal ratios of Archaeornithomimus are not necessarily arctometatarsalian.

Garudimimus has been only identified from MPC-D100/13. However, there may be additional specimens among the large bonebed that includes at least five Bayshi Tsav individuals and several unidentified ornithomimosaurs from other locations in the Bayan Shireh Formation.

Source: Wikipedia