[D] Erlikosaurus andrewsi [Su] [sG] [T]
Describer
Barsbold & Perle, 1980; Clark, Perle & Norell, 1994
Time
Cretaceous Late Cenomanian Turonian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Therizinosauroidea Therizinosauridae
Diet
?
Fossilsite
Baynshirenskaya Svita, Omnogov, Mongolia
Length
5 meter
Info
Genus - Typespecies - Skull
Barsbold, 1983
Holotype
PST GIN AN MNR no. 100/111; skull, individual cervical vertebrae, incomplete hindlimbs.
Erlikosaurus is known from a skull, some neck vertebrae, a humerus and both feet its the only therizinosaurid know from well preserved, well described cranial material (Clark et al., 1994). The jaws are toothless at the front, the external nares are greatly elongated, a secondary palate is well developed, the basicranium and ear region is enlarged and pneumatized, the pelvis is ophistopubic, the ilium is broad and short with a flaring anterior flange, and four toes of each foot contacted the ground.
Associated remains are reported from the Irendabasu beds of Inner Mongolia (Currie & Eberth, 1993). Erlikosaurus is smaller than most therizinosaurids such as Segnosaurus, the unguals however are more trenchant. The premaxilla is edentulous. The external naris isrelatively larger then those of other theropods.
Description
Skull with moderately elongated facial region. Highly elongated external nares. Intermaxillary bones in the very anterior part, occlusal edge of the lower jaw edentulous and supposedly covered with a horny beak. Basisphenoid capsule absent, but the anterior part of the basicranium is very wide in dimensions and has a well-developed system of intracranial sinuses. Basipterygoid processes reduced, and basipterygoid articulations blocked. Parabasal canals formed by the basipterygoid processes, the anterior part of the basisphenoid, and the pterygoid. Articulation of the vomers with the basisphenoid is conditionally constructed along a paleognathous line.
Posterior processes of vomers are lamellar, ventrally fused along the midline, and form a V-shaped transverse cross-section. Posteriorly, the reach the basisphenoidal rostrum and are connected with it; at the same time, the posterior end of the vomerine processes forks, covering the ventral opening of the rostrum. The lower jaw is narrowed and slightly concave anteriorly. Mandibular fenestra elongated. Dentary with large angular process. Splenial with triangular-ending anterior and angular processes, and does not reach the symphysis. Coronoid absent. Adductor fossa large and elongated. Coronoid process weakly expressed. Symphysis shortened. 31 small, straight teeth in each mandibular ramus, the anterior ones remarkable in being larger in size than those posteriorly.
The cervical vertebrae are disproportionately large, elongated, and have low neural arches. Humerus somewhat shortened, with a moderately large deltopectoral crest. [All] metatarsals are massive, with widened ends (including the proximal end), and form a noncompact structure. Metatarsal I is shortened, and participates in the formation of the laterally elongate proximal articular surface of the pes. Metatarsal [V] is rudimentary. Pedal digit I is the most shortened, II and III are subequal in size, and IV is the most slender. The phalanges of pedal digits I-III are fairly similar in construction, relatively shortened, and have wide articular surfaces. Phalanges 2 and 3 are highly shortened and disc-like in digit I. Ungual phalanges are relatively large, curved, and slightly laterally compressed.
Comparisons
Similarities between Erlikosaurus and Segnosaurus include the construction of the lower jaw and teeth, the disproportionately large caudal vertebrae, the clear degree of shortening of the forelimbs, and the non-compact pedal structure. At the same time, the smaller and straighter teeth, the large diastema in the anterior lower jaw, the edentulous portion of the lower jaw, and the highly compressed pedal ungual phalanges clearly differentiate Erlikosaurus from Segnosaurus.
Discussion
The similarities between Erlikosaurus and Segnosaurus show their undoubtedly related nature, and clearly distinguish them from other carnivorous dinosaurs. It is not possible to compare them exactly based on the materials of both genera, and it is possible that in reality the differences between Erlikosaurus and Segnosaurus may turn out to be more basic, as supported by such characteristic signs as the shape of the pedal ungual phalanges, etc.
Source: Polyglot Paleontologist
Barsbold & Perle, 1980; Clark, Perle & Norell, 1994
Time
Cretaceous Late Cenomanian Turonian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Therizinosauroidea Therizinosauridae
Diet
?
Fossilsite
Baynshirenskaya Svita, Omnogov, Mongolia
Length
5 meter
Info
Genus - Typespecies - Skull
Barsbold, 1983
Holotype
PST GIN AN MNR no. 100/111; skull, individual cervical vertebrae, incomplete hindlimbs.
Erlikosaurus is known from a skull, some neck vertebrae, a humerus and both feet its the only therizinosaurid know from well preserved, well described cranial material (Clark et al., 1994). The jaws are toothless at the front, the external nares are greatly elongated, a secondary palate is well developed, the basicranium and ear region is enlarged and pneumatized, the pelvis is ophistopubic, the ilium is broad and short with a flaring anterior flange, and four toes of each foot contacted the ground.
Associated remains are reported from the Irendabasu beds of Inner Mongolia (Currie & Eberth, 1993). Erlikosaurus is smaller than most therizinosaurids such as Segnosaurus, the unguals however are more trenchant. The premaxilla is edentulous. The external naris isrelatively larger then those of other theropods.
Description
Skull with moderately elongated facial region. Highly elongated external nares. Intermaxillary bones in the very anterior part, occlusal edge of the lower jaw edentulous and supposedly covered with a horny beak. Basisphenoid capsule absent, but the anterior part of the basicranium is very wide in dimensions and has a well-developed system of intracranial sinuses. Basipterygoid processes reduced, and basipterygoid articulations blocked. Parabasal canals formed by the basipterygoid processes, the anterior part of the basisphenoid, and the pterygoid. Articulation of the vomers with the basisphenoid is conditionally constructed along a paleognathous line.
Posterior processes of vomers are lamellar, ventrally fused along the midline, and form a V-shaped transverse cross-section. Posteriorly, the reach the basisphenoidal rostrum and are connected with it; at the same time, the posterior end of the vomerine processes forks, covering the ventral opening of the rostrum. The lower jaw is narrowed and slightly concave anteriorly. Mandibular fenestra elongated. Dentary with large angular process. Splenial with triangular-ending anterior and angular processes, and does not reach the symphysis. Coronoid absent. Adductor fossa large and elongated. Coronoid process weakly expressed. Symphysis shortened. 31 small, straight teeth in each mandibular ramus, the anterior ones remarkable in being larger in size than those posteriorly.
The cervical vertebrae are disproportionately large, elongated, and have low neural arches. Humerus somewhat shortened, with a moderately large deltopectoral crest. [All] metatarsals are massive, with widened ends (including the proximal end), and form a noncompact structure. Metatarsal I is shortened, and participates in the formation of the laterally elongate proximal articular surface of the pes. Metatarsal [V] is rudimentary. Pedal digit I is the most shortened, II and III are subequal in size, and IV is the most slender. The phalanges of pedal digits I-III are fairly similar in construction, relatively shortened, and have wide articular surfaces. Phalanges 2 and 3 are highly shortened and disc-like in digit I. Ungual phalanges are relatively large, curved, and slightly laterally compressed.
Comparisons
Similarities between Erlikosaurus and Segnosaurus include the construction of the lower jaw and teeth, the disproportionately large caudal vertebrae, the clear degree of shortening of the forelimbs, and the non-compact pedal structure. At the same time, the smaller and straighter teeth, the large diastema in the anterior lower jaw, the edentulous portion of the lower jaw, and the highly compressed pedal ungual phalanges clearly differentiate Erlikosaurus from Segnosaurus.
Discussion
The similarities between Erlikosaurus and Segnosaurus show their undoubtedly related nature, and clearly distinguish them from other carnivorous dinosaurs. It is not possible to compare them exactly based on the materials of both genera, and it is possible that in reality the differences between Erlikosaurus and Segnosaurus may turn out to be more basic, as supported by such characteristic signs as the shape of the pedal ungual phalanges, etc.
Source: Polyglot Paleontologist