Dunkleosteus terrelli Fish Jaw

Description

Dunkleosteus terrelli Fish Jaw Replica measures 425mm or 16.7 inches. Dunkleosteus terrelli Fish Jaw Replica is museum quality polyurethane cast. Made in the USA. Dinichthys terrelli is the scientific name. Dinichthys Jaw (inferognathal). From the heavily armored skull of the giant Devonian Placoderm fish.

Dunkleosteus terrelli or Dinichthys possessed a four bar linkage mechanism for jaw opening that incorporated connections between the skull, the thoracic shield, the lower jaw and the jaw muscles joined together by movable joints. This mechanism allowed them to both achieve a high speed of jaw opening, opening their jaws in 20 milliseconds and completing the whole process in 50 to 60 milliseconds. Fossils of Dunkleosteus or Dinichthys are frequently found with boluses of fish bones, semi-digested and partially eaten remains of other fish.

The largest species, D. terrelli, is estimated to have grown up to 28.8 ft. in length and 4.4 short tons in weight, making it one of the largest placoderms to have existed. Like other placoderms, Dunkleosteus had a two-part bony, armoured exterior, which may have made it a relatively slow but powerful swimmer. Instead of teeth, Dunkleosteus terrelli or Dinichthys possessed two pairs of sharp bony plates which formed a beak like structure. Dunkleosteus terrelli, together with most other placoderms, may have also been among the first vertebrates to internalize egg fertilization, as seen in some modern sharks.

Mainly the armored frontal sections of specimens have been fossilized, and consequently, the appearance of the other portions of the fish is mostly unknown. In fact, only about 5 percent of Dunkleosteus or Dinichthys specimens have more than a quarter of their skeleton preserved. Because of this, many reconstructions of the hindquarters are often based on smaller arthrodires, such as Coccosteus, which had preserved hind sections. An exceptionally preserved specimen of D. terrelli preserves ceratotrichia in a pectoral fin, implying that the fin morphology of placoderms was much more variable than previously thought, and was heavily influenced by locomotory requirements. This knowledge, coupled with the knowledge that fish morphology is more heavily influenced by feeding niche than phylogeny, allowed a 2017 study to infer the body shape of D. terrelli or Dinichthys.

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