Haikoucaris
| Haikoucaris | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| early Cambrian | ||||||||||||
| 525 million years | ||||||||||||
| Locations | ||||||||||||
|
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Haikoucaris | ||||||||||||
| Chen , Waloßek , Maas , 2004 | ||||||||||||
| species | ||||||||||||
|
||||||||||||
Haikoucaris is an extinct species of animals from the early Cambrian . Fossils of its only known representative so far, Haikoucaris ercaiensis , were discovered during excavations in the Maotianshan shale in the Chinese province of Yunnan , a fossil deposit ofthe so-called Chengjiang faunal community , and described scientifically for the first time in 2004. The name Haikoucaris can be traced back to the site near the southern Chinese city of Haikou . Haikoucaris is considered to be the oldest known representative of the arachnid line.
Occurrence
Haikoucaris is a rare member of the Chengjiang Faunal Community of the early Cambrian. So far, only a few, partly incomplete, fossils have been found in the Maotianshan schist.
features
Haikoucaris ercaiensis was about 38 mm long. Its segmented body was protected by an exoskeleton with a head shield and 13 back plates ( tergites ). The limbs on the trunk of Haikoucaris resemble the split- bone-like articulated extremities of Alalcomenaeus . They wore firm bristles ( setae ) on the paddle-shaped exopods , especially on the rear body segments. Haikoucaris ' eyes , difficult to stand out from the head shield, were smaller than Yohoia's . The pair of so-called Great Appendages ("large appendages") on the head, which were about a quarter of the length of the body, are striking . These Great Appendages had claws that resemble the chelicerae of the jaw- claw-bearers . It is believed that the claws were used to catch prey.
Systematics
Haikoucaris ercaiensis exhibits numerous features of today's jaw-claw bearers . The great appendages of Haikoucaris ercaiensis are discussed as preliminary stages of the jaw-claws ( chelicerae ) of the jaw-claw carriers. Based on the anatomy of the Great Appendages, Haikoucaris ercaiensis is more closely related to present-day jawbones than the so-called Megacheira Yohoia , Jianfengia , Alalcomenaeus and Leanchoilia .
literature
- Chen J, Waloszek D, Maas A: A new “great appendage” arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero − ventral appendages . In: Lethaia . 37, 2004, pp. 3-20.