hagfish, primitive, jawless marine fish of the family Myxinidae, of worldwide distribution in cold and temperate waters. Its rudimentary skeleton, of cartilage rather than bone, has a braincase, but no jaw. The circular sucking mouth has rows of horny teeth. There is a single median ...
Figure 1.3.Skeleton of head region ofEptatretussp., left-lateral view. The tooth plate is shown in both its retracted and protracted positions. Adapted from Ayers, H., Jackson, C.M., 1900. Morphology of the Myxinoidei 1. Skeleton and musculature. Bull. Cincinnati Univ. Ser. II 1, 5–...
Their skeleton is made up entirely of cartilage. They have very poorly developed eyes located just under the skin and are almost blind. They do however have finely developed senses of smell & touch which help them find food in the darkness of the deep sea. There are 4 small sensing ...
Once they locate a corpse, they usekeratinplates on their tongues to rasp at the flesh. Hagfish have askeletonof cartilage and have secondarily lost theirvertebrae, allowing them to tie themselves into knots and gain leverage on the bodies they feed on (Martini, 1998). The absence of vertebr...
Thus, it is reasonable to assume that the hagfish vertebral elements, like the rest of the skeleton, represent a secondary degenerated condition.doi:10.1007/978-4-431-56609-0_29Kinya G. Ota
Hence, we can no longer exclude the hagfish from the Vertebrata simply due to the absence of a cartilaginous axial skeleton, which has now been disproved (Fig. 5). Although our developmental study suggested a sclerotomal origin for the ventral elements, the origin of the dorsal element, ...
The first mineralised skeleton was in the form of small 'odontodes' made up by acellular bone and dentine in the dermis, which later fuse into larger plates. All jawless vertebrates that produce bone and dentine are stem jawed vertebrate, or gnathostomes, and informally referred to as '...
The conodont animal is almost exclusively represented in the fossil record by the phosphatic elements of the feeding apparatus, which was the only mineralized component of the skeleton. Only 12 specimens have been found which preserve the soft tissue anatomy of the animal. The animal possessed a ...
In agnathans, the blood-sinus system may function, at least in part, as a kind of hydrostatic skeleton that transduces the force generated by muscular contraction.doi:10.1111/j.1463-6395.1993.tb01237.xKazuhiko TsunekiYutaka KoshidaJohn Wiley & Sons, Ltd.Acta Zoologica...
We then discuss how studies of cyclostomes have provided important insight into the evolution of fins, jaws, skeleton and neural crest. INSET: Box 1. Glossary.ShimeldDepartmentSebastianDepartmentM.DepartmentEBSCO_AspDevelopmentShimeld SM, Donoghue PCJ: Evolutionary crossroads in developmental biology: ...