Anchisaurus ‭(‬Near lizard‭)‬

Short Info

Anchisaurus ‭(‬Near lizard‭)‬

Phonetic : An-chih-sore-us.

Named By : Othniel Charles Marsh‭ ‬-‭ ‬1885

Diet : Herbivore

Size : Estimated 2 – 4 meters long

Type of Dinosaur : Sauropod

Type Species : A.‭ ‬polyzelus‭ (‬type‭)

Found in : USA

When it Lived : Early Jurassic, 190 million years ago

Anchisaurus is an genus that belongs to basal sauropodomorphs. It was alive during its Early Jurassic Period, and its fossils were discovered in the red sandstones of the Portland Formation in the northeastern United States, which was formed in the Hettangian period to the Sinemurian age, which was between 200 to 195 million years in the past. Up until recently, it was classified as a part of Prosauropoda. The name of the genus Anchisaurus originates from the Greek Agkhi (agkhi) the word anchi which means “near, close” + Greek sauros (sauros); “lizard”. Anchisaurus was created to replace “Amphisaurus”, which was an alternative term for the film of Hitchcock “Megadactylus”, both of were previously utilized for other species.

Sauropodomorph bones were the first recorded within North America in 1818, after the discovery of bones in the hands of Mr. Solomon Ellsworth, Jr. when he was digging an underground well using gunpowder in East Windsor, Connecticut. When they made the discovery, it was believed that the bones could be the remains of a human being, however the existence of tail vertebrae disproved this notion. They are now recognized as being of an indeterminate sauropodomorph perhaps closer to the prosauropods of the plateosaurian.

In 1855 the first kind specimen of Anchisaurus polyzelus AM 41/109, that is in Amherst College Museum of Natural History. Amherst College Museum of Natural History It was discovered at the request of William Smith in Springfield, Massachusetts while blasting a well to build the waterhouse of the Springfield Armory. Unfortunately both East Windsor and Springfield specimens were damaged severely by blasting that took place at the construction sites on which they were discovered, and most pieces of bones accidentally thrown away by construction workers or saved by curious people who were watching. In the end, these dinosaurs were discovered from the remains of a few fragments.


Large marsh anchisaurus
O.C. Marsh., Public domain, via Wikimedia Commons

In 1863 Edward Hitchcock Jr., son of Ichnologist Edward Hitchcock, Edward Hitchcock Jr wrote about the Springfield remains as a supplement to his father’s research on fossil footprints. The evidence suggested they might explain a strange reptile track. Then, he contacted British paleontologist Richard Owen. Owen suggested naming the discoveries as a new species. Owen suggested Megadactylus as the name “large finger” in Greek as a reference to the massive thumbs of this animal. Hitchcock Jr himself then chose the precise name, polyzelus “much sought for” in Greek refers on the possibility that his dad long ago unsuccessfully tried to identify the track maker.

In 1877, the professor Othniel Charles Marsh had observed that Megadactylus was a subject of Megadactylus Fitzinger 1843. It was a subgenus within the Lizard Genus Stellio. He changed Megadactylus with Amphisaurus, “near saurian” possibly in reference to Marsh’s interpretation as an intermediate between primitive dinosaurs at the time, the British Palaeosaurus was a prime illustration of what was believed as a dinosaur that was primitivealong with other dinosaurs that were derived from them. The year 1885 was when Marsh was able to discover that the name was also in the spotlight, as was an Athracosaurian Amphisaurus Barkas 1870 which was later replaced with Anchisaurus and the identical meaning.

Nearly complete examples were found at Manchester, Connecticut. The year 1884 saw the construction of a string of bridges was constructed over Hop Creek. Sandstone blocks were cut from Wolcott’s Quarry north of Buckland Station. On the 20th of October an amateur paleontologist, Charles H. Owen, discovered that a stone block was removed that contained the hind portion of the Skeleton. He alerted Marsh who, with T.A. Bostwick to act as an intermediary purchased the skeleton from quarry’s proprietor, Charles O. Wolcott. Marsh attempted to fix the forward part of the skeleton, but it was already used as a bridge abutment. This specimen YPM 208 was called Anchisaurus major “the larger one” in 1889 by Marsh during 1889. The bridge eventually was torn down in the month of August in 1969 John Ostrom would save the front block. Then, two additional dinosaur fossils were discovered within the quarry. Six meters to the south of the initial find, the second skeleton was seen on the quarry’s face. This was removed in a single piece and assigned the inventory number YPM 1883. In Yale the skull was found in the area of the skull was cut off and was renamed specimen YPM 40313. The year 1891 was the time Marsh established Anchisaurus major as a distinct genus, Ammosaurus, also known as the “sand saurian”. The same journal, Marsh designated YPM 1883/YPM 40313 as the brand new species within Anchisaurus, Anchisaurus colurus, “the mangled one”. They were used as templates of which O.C. Marsh in 1893 rebuilt the skeleton. It was restored in 1893. Manchester remains are believed to be closely related to Anchisaurus polyzelus. They are the East Windsor and Manchester specimens are located in the Peabody Museum of Natural History located at Yale University.

The most well-known species is Hitchcock’s A. polyzelus. Marsh’s A. major (also known as Ammosaurus), A. solus as well as A. colurus (also also known as Yaleosaurus) are now been accepted as synonyms of A. polyzelus. Their apparent differences are due to confusion and different growth stages. In 2015 the ICZN officially declared A. colurus the most complete specimen type of A. colurus as the Neotype of the Genus Anchisaurus and also the A. polyzelus species A. polyzelus. This renders A. polyzelus as well as A. colurus to be objective synonyms (both names are derived from the exact similar fossil).

Broom has named Gyposaurus capensis back in the year 1911 after he discovered bones within South Africa but Peter Galton named these Anchisaurus capensis in the year 1976. The species has since been classified again and is likely a young Massospondylus carinatus. G. sinensis is mentioned here, but it appears to be a separate animal.

It is believed that the Navajo Sandstone of Arizona is similar to it is in the Portland Formation, and has produced prosauropod remains which are referred to as Ammosaurus. However, it’s possible that they belong to the Genus Massospondylus that is known as a distinct species in South Africa.

Within the east Canadian Province in Nova Scotia, scientists have discovered prosauropods from the McCoy Brook Formation, which is between 200 and 197 million years old. It dates back to early in the Early Jurassic Hettangian stage. This Nova Scotia material provides clues regarding the diet of the species. There were a lot of gastroliths, which are stones that were taken in to grind plants in the intestine located in the abdomen and bone was also found in the skull of tiny sphenodont called Clevosaurus. These dinosaurs were omnivores with their diet mostly comprised of plants, but occasionally a little meat. But, the remains have not been completely described or illustrated and were not even formally attributed to Ammosaurus. Another study has found them to be a new sauropodomorph taxon Fendusaurus Eldoni.

Anchisaurus was a small dinosaur with an average length of 2 meters (6.6 feet) which is why it was initially thought to be human bones. It could have weighed between 27 and 27 kilograms (60 lbs). However, Marsh’s type A. major (also called Ammosaurus) was much larger, ranging in the range of 2.5 up to four meters (8 2 inches to 13 feet 1 inch) Some estimates suggest an estimated weight of up around 32 kg (70 lbs). Gregory S. Paul estimated its length to be 2.2 meters (7.2 feet) with a weight of 20 kg (44 pounds) in 2010.

Based on the evidence of Cf. Otozoum tracks in the Connecticut Valley, Anchisaurus could grow to even larger sizes. Otozoum tracks were formed by a semibipedal-quadrupedal sauropodomorph near or on the line leading towards Eusauropods. Anchisaurus is among two sauropodomorphs found in the area. From the 4 identified samples from Anchisaurus, Yates estimated that the animal could measure at least 4.9 meters (16 feet) long. This is consistent with the average size of the adult Eubrontes track maker located in Hartford as well as Deerfield basins. Based on the biggest known Eubrontes footprint, extremely huge individuals of Anchisaurus likely measured as high as 6 meters (20 feet) long.

Source: Wikipedia