Cretoperipatus burmiticus
| Cretoperipatus burmiticus | ||||||||||||
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| Lower chalk | ||||||||||||
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| Scientific name | ||||||||||||
| Cretoperipatus burmiticus | ||||||||||||
| Engel & Grimaldi , 2002 |
As cretoperipatus burmiticus is called an extinct kind of velvet worms (Onychophora) located in Cretaceous amber from Southeast Asia Myanmar received. She is the only member of the Mesozoic known (Mesozoic) nature of this group of animals and can already one of the modern family , the peripatidae be assigned.
Cretoperipatus burmiticus was first discovered in 2002 by the paleontologist David. A. Grimaldi and Michael S. Engel described; the genus name is made up of the components creto for the geological period of the Cretaceous and peripatus for the type genus of Peripatidae; the species epithet burmiticus refers to the name of Bernstein -Varietät burmite in which the fossil was found.
features
Only the front half of the animal is preserved, while the rear part is presumably rotten. Five pairs of legs are visible, which reveal a foot structure that is unique compared to modern species.
The mouth, surrounded by small bulges, the papillae, in which the jaws were also located, is located on the animal's belly, as is the case with today's velvet worms. The section of the head in front of it was distorted when it was enclosed in amber and is only inadequately recognizable; Antennae and oral papillae were presumably present.
The skin surface is covered by numerous wart-shaped elevations and finely ringed, with about twelve complete rings per segment, which do not run into one another laterally. The distance between the second and third pair of legs is 0.69 millimeters, the distance between the third and fourth 0.77 millimeters.
At the base of each leg there is an opening, the nephridiopore , at which the excretory duct called nephridia flows out, through which products of the nephridia could be released into the environment. Coxalorgane or Cruraldrüsen , special organs that are present in many modern Stummelfüßern in the legs, can not make it. Near the body ( basal ), the leg is covered with five papillae, two of which, however, are only weakly developed. At the foot end there are three hardened pillows, of which the furthest ( distal ) one is slightly smaller than the other two. In addition to the two long, strong and curved claws there is a distal papilla. The total length of the foot is 0.15 millimeters.
The sex of the only known individual is unknown.
Find properties
Cretoperipatus burmiticus was found in an amber variant called Burmit near the Noije Bum hill, which in turn is 32 kilometers southwest of the village of Tanai in the state of Kachin in Myanmar.
The fossil presumably originated near the transition from the lower to the upper Cretaceous about 100 million years ago. At that time the region lay between the 10th and 15th parallel north latitude, so that Cretoperipatus burmiticus probably lived in tropical conditions. The amber was created by hardening the resin of the coniferous plants (Pinophyta), probably from the cypress family (Cupressaceae); perhaps they were even close relatives of today's primeval sequoias ( Metasequoia ).
The holotype of the species and at the same time the only known specimen is now kept in the American Museum of Natural History in New York.
Systematic classification
There is no serious doubt as to the assignment of the fossil to the velvet worms. The authors even assume that the species can already be assigned to the modern Peripatidae family . This would mean that the splitting of the stumpole line into the two modern families must have occurred more than 100 million years ago - a result that fits well with biogeographical considerations. On the other hand, Cretoperipatus burmiticus cannot yet be assigned to any of the modern genera .
Due to its temporal classification, the species closes a gap between the first species Helenodora inopinata , which clearly belongs to the velvet worms, from the geological period of the Carboniferous and two tertiary species, Succinipatopsis balticus and Tertiapatus dominicanus , which are known from the Eocene and Miocene . Nevertheless, there are more than 200 million years of geological history between Helenodora inopinata and Cretoperipatus burmiticus , so that the fossil record of the velvet worms is still extremely patchy; the four species mentioned together form the entire known fossil record.
literature
- DA Grimaldi, MS Engel, PC Nascimbene, Fossiliferous Cretaceous Amber from Myanmar (Burma): Its rediscovery, biotic diversity, and paleontological significance , American Museum Novitates, 3361 , 2002, p. 24