Janjucetus
From Wikipedia, the free encyclopedia
 |
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 |
||||||||||||||||
|
|
||||||||||||||||
|
Extinct (fossil)
|
||||||||||||||||
| Scientific classification | ||||||||||||||||
|
||||||||||||||||
|
|
||||||||||||||||
| Janjucetus hunderi Fitzgerald, 2006 |
Janjucetus was a prehistoric whale genus belonging to the group Mysticeti, which includes all baleen whales. Janjucetus hunderi is the only known species of the genus. Janjucetus lived during the Late Oligocene, over 25 million years ago. Unlike other baleen whales, Janjucetus was equipped with teeth used for gripping and shredding prey and is thought to have had little or no baleen. Janjucetus ate large fish and possibly even larger prey, such as small sharks. It would have relied on active hunting routines due to its lack of baleen or use of echolocation. Fossils, to date, have only been found in Australian waters.
Contents |
[edit] Description
Janjucetus' body length is estimated at around 3.5 metres (11.5 feet), about the size of the bottlenose dolphin. This size is relatively small compared to other baleen whales discovered. Although related to the baleen whales, Janjucetus had 1.4 inch teeth that were sharp and serrated. However, the whale did show many similarities to other baleen whales in its skull. The eyes of the whale are estimated to be very large, giving it exceptional eyesight. Since Janjucetus did not possess echolocation, it probably would have relied on its good eyesight instead. Janjucetus had a short, yet broad snout, with clearly overhanging teeth and elongated nasal passages. Janjucetus' jaw was fairly robust and large, perfectly equipped for the task of capturing and shredding live prey.
Janjucetus is thought to have been related to several other prehistoric baleen whales, including Mammalodon. However, the characteristics shown by Janjucetus are considered to be unique among all Mysticeti, perhaps even all Cetaceans.
[edit] History
The only known fossil of Janjucetus was found in the late 1990s by an Australian surfer near the Victorian township of Jan Juc, after which the ancient whale is named. The whale, Janjucetus hunderi, is also named after the teenage surfer who found it, Staumn Hunder. Hunder is said to have seen the brown fossils on a boulder while he surfed. Soon after discovering the site, Hunder and his father removed the boulder and transported it to the Monash University for further research. However, until Erich Fitzgerald started long-term research on the fossils in 2003, little had been established about the whale remains. Fitzgerald first published his findings in the journal, Proceedings of the Royal Society B.
The well-preserved fossil remains, which include a nearly complete skull, mandibles, teeth, vertebrae, ribs, scapulae and a radius, are currently held in the Museum Victoria Palaeontology Collection in Melbourne, Australia. The holotype of Janjucetus is the most complete Paleogene cetacean find from Australia yet to be found.
[edit] Paleobiology
Janjucetus ate much larger prey than its baleen relatives, often hunting fish or slightly larger creatures. Janjucetus is thought to share a feeding pattern similar to that of the present leopard seal and to varied ancient marine reptiles. Both would attack their prey quickly and proceed to strip flesh from it.
Due to the lack of the common features of echolocation-able Cetaceans, such as an enlarged front temple, it has been established that Janjucetus was unable to perform echolocation. Whether it could receive echolocation signals is however unknown.
[edit] References
Fitzgerald, E.M.G. (2006). "A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales." Proceedings of the Royal Society B. ISSN 0962-8452.
