The Cretaceous theropodus dinosaur Gorgosaurus / by Lawrence M. Lambe.

  • Lambe, Lawrence M. (Lawrence Morris), 1863-1919.
Date:
1917
Catalogue details

Licence: In copyright

Credit: The Cretaceous theropodus dinosaur Gorgosaurus / by Lawrence M. Lambe. Source: Wellcome Collection.

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    Figures 32 and 37 are included in the illustrations through the courtesy of Dr. Charles W. Gilmore of the United States National Museum, Washington, D C. Figures 1 to 4 are from photographs taken by C. M. Sternberg in the field. ORIGINAL DESCRIPTION OF GORGOSAURUS. The type specimen of Gorgosaurus libratus was described in April, 1914, in the following words: “The osteological characters of one of the carnivorous dinosaurs of the Cretaceous are revealed in a wonderful manner by a nearly complete skeleton obtained last summer.The specimen includes the head, the greater part of the vertebral column, the pectoral and pelvic arches, one at least of the fore limbs complete, both hind limbs also complete, the ribs, and apparently the entire series of abdominal ribs. The cervical vertebrae appear- to be missing, but as all of the sandstone matrix has not yet been removed, they, or some of them, as well as the other fore limb, may yet be uncovered. The extreme end of the tail, back of the twenty-second caudal vertebra, was not found. “The mandible is present and all of the teeth, both upper and lower, are in place, giving the complete dentition. The writer has already published a short description of the fore limb which has not hitherto been known in any of the Cretaceous carnivorous dinosaurs. Nor has a complete series of ventral ribs in any of these reptiles previously been discovered. “For the undescribed genus of Theropodous dinosaur, brought to light by this magnificent specimen, the name Gorgosaurus is proposed. The species may be called libratus in reference to the animal’s probable well-balanced and easy gait. “Gorgosaurus libratus, gen. et sp. nov.” “Carnivorous dinosaur of large size, reaching a length of about 29 feet; head narrow and moderately elongate; trunk compact; fore¬ limbs minute; hind limbs long and robust; tail nearly half the total length of the animal, tapering, and with only a slight lateral compression. In the skull there is a large antorbital vacuity, preceded by a very small opening in the centre of a depressed area. No triangular alveolar plates on the inner sides of the jaws. A foramen present in the sur- angular, far back and near its upper border. No presplenial. Teeth trenchant, powerful, 4 premaxillary, 13 maxillary, ancj 14 dentary. First tooth of the maxilla similar in shape and size to those of the pre¬ maxilla. Vertebrae slightly amphicoelus, concave on the sides and be¬ neath; 2 cervico-dorsals, 11 dorsals, 5 sacrals, and about 34 caudals. Neural spines short throughout the vertebral column. Chevron bones