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Alectrosaurus Explained...🦖💨⚠️☠️ #dinosaur#nature#science #explained#archeology#predetor#island#fyp
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Alectrosaurus (/əˌlɛktroʊˈsɔːrəs/; meaning "alone lizard") is a genus of tyrannosauroid theropod dinosaur that lived in Asia during the Late Cretaceous period, about some 96 million years ago in what is now the Iren Dabasu Formation.
It was a medium-sized, moderately-built, ground-dwelling, bipedal carnivore, estimated at 5 to 6 m (16 to 20 ft) with a body shape similar to its much larger advanced relative, Tyrannosaurus. Alectrosaurus was a very fast running tyrannosauroid as indicated by the elongated hindlimbs that likely filled the niche of a pursuit predator, a trait that seems to be lost by the advanced and robust tyrannosaurids, in adulthood.In 1923, the Third Asiatic Expedition of the American Museum of Natural History, led by chief paleontologist Walter W. Granger, was hunting for dinosaur fossils in Mongolia. On April 25 in the gobi desert, assistant paleontologist George Olsen excavated and recovered the holotype AMNH FARB 6554, a nearly complete right hindlimb. This included a virtually complete right hindlimb with some elements from the left pes and two manual unguals. On May 4, Olsen discovered another specimen approximately 30 m (98.4 ft) away from his first find, catalogued as AMNH 6368. This specimen included a right humerus, two incomplete manual digits, four fragmentary caudal vertebrae, and other two or three unspecified elements that were discarded due to bad preservation. These discoveries were made at the Iren Dabasu Formation in what is now the Inner Mongolia Autonomous Region (Nei Mongol Zizhiqu) of China.
Both genus and species were formally described and named by the American paleontologist Charles Gilmore in 1933. The generic name, Alectrosaurus, can be translated as "alone lizard" or "mateless lizard", derived from the Greek words ἄλεκτρος (meaning alone or unmarried) and σαῦρος (meaning lizard). The specific name, olseni, is in honor of George Olsen, who discovered the first specimens.Since then, more material has been referred to Alectrosaurus. Possible findings of two additional specimens at the Bayan Shireh Formation were reported and described by the Mongolian paleontologist Altangerel Perle in 1977. The specimen IGM 100/50 consists of a partial maxilla, scapulocoracoid and manual ungual, and specimen IGM 100/51 consists of a fragmentary skull with lower jaws and other elements, incomplete ilium, and metatarsals of the right foot. These fossils were found in Outer Mongolia.Iren Dabasu and Bayan Shireh dinosaur faunas are very similar, so it is not surprising that a species of Alectrosaurus would be found there. However, it is possible that these specimens may not be referable to Alectrosaurus, because of some tyrannosaurid traits found in the Mongolian specimens which the holotype does not possess.Alexander Averianov and Hans-Dieter Sues 2012 have estimated that the Iren Dabasu Formation is Santonian in age, correlating the Upper Bayan Shireh Formation.Van Itterbeeck et al. 2005 suggested that the Iren Dabasu Formation is probably Campanian-Maastrichtian in age and possibly correlated with the Nemegt Formation.
Near the holotype, the specimen AMNH FARB 6266 was found in the same strata but at different points also in 1923. It consists of premaxillary and lateral teeth, incomplete left lacrimal, maxillary process of the left jugal, partial right quadratojugal, jugal process of the right ectopterygoid and the quadrate ramus to the right pterygoid. Although the specimen seems to represent a smaller individual. Its affinity to Alectrosaurus is somewhat unresolved since the specimen lacks hindlimb material, making direct comparisons with Alectrosaurus quite complicated.The lectotype AMNH 6554 is fragmentary, consisting of a nearly complete right hindlimb only lacking the distal tarsal elements; left metatarsals II, III and IV, and a fragmentary distal foot of a pubis, however it is unknown which pubis represents.
It was a medium-sized tyrannosauroid, reaching a length between 5 and 6 m (16 and 20 ft), and a weight ranging from 454 to 907 kg (1,001 to 2,000 lb).Overall, the hindlimbs were rather gracile, in contrast to the robust tyrannosaurids. The length of its tibia (shinbone) and femur (thighbone) are very close, in contrast to the majority of other tyrannosauroids, where the tibia is longer. The femur measures 72.7 cm (727 mm) and the tibia 73 cm (730 mm). The metetarsals are also closer in size to the tibia than in most other tyrannosauroids, where they are usually longer; the third is the largest, measuring 48 cm (480 mm) long.The astragalus and calcaneum are nicely preserved, although the astragalus seems to be slightly damaged. They are strongly attached, but not fused.Following the original description of Alectrosaurus, it can be distinguished by the following traits: long slender-limbed type of tyrannosauroid; humerus long and slender; ungual and phalanx of digit I robust, laterally compressed and strongly curved, femur and tibia subequal in length.
It was a medium-sized, moderately-built, ground-dwelling, bipedal carnivore, estimated at 5 to 6 m (16 to 20 ft) with a body shape similar to its much larger advanced relative, Tyrannosaurus. Alectrosaurus was a very fast running tyrannosauroid as indicated by the elongated hindlimbs that likely filled the niche of a pursuit predator, a trait that seems to be lost by the advanced and robust tyrannosaurids, in adulthood.In 1923, the Third Asiatic Expedition of the American Museum of Natural History, led by chief paleontologist Walter W. Granger, was hunting for dinosaur fossils in Mongolia. On April 25 in the gobi desert, assistant paleontologist George Olsen excavated and recovered the holotype AMNH FARB 6554, a nearly complete right hindlimb. This included a virtually complete right hindlimb with some elements from the left pes and two manual unguals. On May 4, Olsen discovered another specimen approximately 30 m (98.4 ft) away from his first find, catalogued as AMNH 6368. This specimen included a right humerus, two incomplete manual digits, four fragmentary caudal vertebrae, and other two or three unspecified elements that were discarded due to bad preservation. These discoveries were made at the Iren Dabasu Formation in what is now the Inner Mongolia Autonomous Region (Nei Mongol Zizhiqu) of China.
Both genus and species were formally described and named by the American paleontologist Charles Gilmore in 1933. The generic name, Alectrosaurus, can be translated as "alone lizard" or "mateless lizard", derived from the Greek words ἄλεκτρος (meaning alone or unmarried) and σαῦρος (meaning lizard). The specific name, olseni, is in honor of George Olsen, who discovered the first specimens.Since then, more material has been referred to Alectrosaurus. Possible findings of two additional specimens at the Bayan Shireh Formation were reported and described by the Mongolian paleontologist Altangerel Perle in 1977. The specimen IGM 100/50 consists of a partial maxilla, scapulocoracoid and manual ungual, and specimen IGM 100/51 consists of a fragmentary skull with lower jaws and other elements, incomplete ilium, and metatarsals of the right foot. These fossils were found in Outer Mongolia.Iren Dabasu and Bayan Shireh dinosaur faunas are very similar, so it is not surprising that a species of Alectrosaurus would be found there. However, it is possible that these specimens may not be referable to Alectrosaurus, because of some tyrannosaurid traits found in the Mongolian specimens which the holotype does not possess.Alexander Averianov and Hans-Dieter Sues 2012 have estimated that the Iren Dabasu Formation is Santonian in age, correlating the Upper Bayan Shireh Formation.Van Itterbeeck et al. 2005 suggested that the Iren Dabasu Formation is probably Campanian-Maastrichtian in age and possibly correlated with the Nemegt Formation.
Near the holotype, the specimen AMNH FARB 6266 was found in the same strata but at different points also in 1923. It consists of premaxillary and lateral teeth, incomplete left lacrimal, maxillary process of the left jugal, partial right quadratojugal, jugal process of the right ectopterygoid and the quadrate ramus to the right pterygoid. Although the specimen seems to represent a smaller individual. Its affinity to Alectrosaurus is somewhat unresolved since the specimen lacks hindlimb material, making direct comparisons with Alectrosaurus quite complicated.The lectotype AMNH 6554 is fragmentary, consisting of a nearly complete right hindlimb only lacking the distal tarsal elements; left metatarsals II, III and IV, and a fragmentary distal foot of a pubis, however it is unknown which pubis represents.
It was a medium-sized tyrannosauroid, reaching a length between 5 and 6 m (16 and 20 ft), and a weight ranging from 454 to 907 kg (1,001 to 2,000 lb).Overall, the hindlimbs were rather gracile, in contrast to the robust tyrannosaurids. The length of its tibia (shinbone) and femur (thighbone) are very close, in contrast to the majority of other tyrannosauroids, where the tibia is longer. The femur measures 72.7 cm (727 mm) and the tibia 73 cm (730 mm). The metetarsals are also closer in size to the tibia than in most other tyrannosauroids, where they are usually longer; the third is the largest, measuring 48 cm (480 mm) long.The astragalus and calcaneum are nicely preserved, although the astragalus seems to be slightly damaged. They are strongly attached, but not fused.Following the original description of Alectrosaurus, it can be distinguished by the following traits: long slender-limbed type of tyrannosauroid; humerus long and slender; ungual and phalanx of digit I robust, laterally compressed and strongly curved, femur and tibia subequal in length.