Carbotriplura kukalovae
| Carbotriplura kukalovae | ||||||||
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| Temporal occurrence | ||||||||
| Moskovium | ||||||||
| 309 million years | ||||||||
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| Systematics | ||||||||
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| Scientific name | ||||||||
| Carbotriplura kukalovae | ||||||||
| Kluge , 1996 |
Carbotriplura kukalovae is an extinctinsect species from the Pennsylvania (Upper Carboniferous), onlypreservedas a fossil . So far only a single fossil, the type specimen , has been found. The species has received particular attention as itshedslight on the still mysterious early evolution of the winged insects, or pterygota , andrevealsa possible mechanism by which insect wings were formed .
description
It was a large insect, about 10 centimeters long (measured without tail appendages), which is embedded in fine-grained tuffite . The partially poorly preserved fossil is embedded in such a way that you can see its ventral side (the belly side). Two large complex eyes can be seen on the head that protrude laterally (unlike the recent rock jumpers, they do not touch each other). In addition, the basal part of the left antennae and the right maxilla with the five-segment maxillary palpus can be seen. On all three segments of the trunk , flat, sideways-directed protrusions, the paranota, are immediately noticeable, which are rounded at the end. These show neither a joint nor a recognizable vein ; they are interpreted as laterally protruding, undivided plates. Extensions that look very similar are also found on the first nine segments of the abdomen . These are similar in appearance to the tracheal gills with which the aquatic larvae of the mayflies absorb oxygen from the water, but unlike these they sit broadly and immobile on the body and have no recognizable tracheas . On the trunk there are also three elongated, rod-shaped pairs of legs (the basal parts not preserved), with long tarsi , the number of segments of which cannot be given with certainty due to poor preservation; there are at least five tarsi, possibly more. The abdomen consists of ten segments, the last of which are three long tail threads, two lateral cerci and a central paracercus or terminal filum, which are also only partially preserved. The recent mayflies, rock jumpers and fish have similar tail threads . In addition, a two-segment limb rudiment can be seen on at least one abdominal segment (too poorly preserved for a reliable interpretation on others), which is most likely homologous to the appendages called styli on the abdomen of the little fish and rock jumpers .
Research history
The fossil was first described in 1985 by the Czech-Canadian researcher Jarmila Kukalova-Peck and interpreted as the larva of a flying insect that she also found in about the same old and nearby horizons, which she interpreted as a gigantic, extinct mayfly and named Bojophlebia prokopi . 1996 saw the inquiring in Saint Petersburg Nikita Julievich Kluge that the winged insects and the "larva" do not belong together, he interpreted previously regarded as a larva Fossil new as wingless "urine champagne" ( Thysanura ), which he dedicated to the discoverer kukalovae Carbotriplura new named (the otherwise twice given name Bojophlebia prokopi remained the winged insect). In 2014, Arnold Staniczek, Pavel Sroka and Günter Bechly re-examined the fossil stored in the Czech Karst Museum in Beroun (Muzeum Českého krasu v Berouně) and came to conclusions that differed from the previous studies. In doing so, they encountered inconsistencies in Kukalova-Peck's description and illustrations, which they interpret as changes in the original findings, probably caused by overinterpretation or wishful thinking.
Phylogeny
The fossil has numerous features in common with the recent, primarily wingless "urine insects" of the fish and rock diver orders, such as the extensions (Paranota) of the trunk, the tail appendages and the extremities (styli) of the abdomen. However, these are probably plesiomorphies , i.e. features inherited from a common ancestor, which are not illuminating for the interpretation of his relationship. The excesses on the trunk could also have been wing sheaths ; in this case the fossil would have been the larva of a winged insect. This corresponded to the interpretation of Kukalova-Peck. Due to the proportions, however, it could only be an early nymph stage - if this had been the case, the winged insect would have had truly gigantic proportions and far surpassed all recent and fossil insects ever found, which is extremely unlikely.
The fossil does not show any characteristics that would have to be regarded as the undoubted autapomorphies of the rock jumpers, the dicondylia - the common relatives of the fish and the flying insects - or one of these groups separately. In principle, his exact relationship is open; it could belong to the home group of any of these groups. Earlier researchers had therefore left the exact relationship open. Staniczek et al. in their revision now plead for it to be placed in an independent order instead, which they named Carbotriplurida, which they interpret as a sister group of the flying insects. They point out that the insect looks something like how previous researchers reconstructed the hypothetical ancestral form of the flying insects.
Conjectures on biology, evolution of the insect wing
If the kinship interpretation of Staniczek et al. right, if it were a strong support for one of the previously purely hypothetical scenarios of how the wings of insects could have evolved. According to the Paranota theory , these emerged from such lateral outgrowths of the trunk as are so conspicuously present in Carbotriplura . These would initially have been used for gliding or parachute-like to slow down the fall of tree-living insects, later (through gene recruitment: partial takeover of the function of genes for the leg systems) they would have become mobile limbs through muscles. The deposits in which Carbotriplura were found come from a muddy inland lake into which volcanic tuff has also been washed by the movement of water. The insect could have lived on tree-shaped plants such as Cordaitales or Lepidodendraceae on the banks of this lake; his long legs might be adaptations for climbing. Interestingly, even today's tree-dwelling species of rock jumpers can glide at least imperfectly with their Paranota.
swell
- Arnold Staniczek, Pavel Sroka, Günter Bechly: Neither silverfish nor fowl: the enigmatic Carboniferous Carbotriplura kukalovae Kluge, 1996 (Insecta: Carbotriplurida) is the putative fossil sister group of winged insects (Insecta: Pterygota). In: Systematic Entomology. Volume 39, Number 4, October 2014, pp. 619-632. doi : 10.1111 / syen.12076 .
Individual evidence
- ↑ Jarmila Kukalova-Peck (1985): Ephemeroid wing venation based upon new gigantic Carboniferous mayflies and basic morphology, phylogeny, and metamorphosis of pterygote insects (Insecta, Ephemerida). Canadian Journal of Zoology 63: 933-955.
- ↑ N. Ju. Kluge (1996): A new suborder of Thysanura for the Carboniferous insect originally described as larva of Bojophlebia, with comments on characters of the orders Thysanura and Ephemeroptera. Zoosystematica Rossica 4: 71-75.
- ↑ AP Rasitsyn: Subclass Lepismatona. In: AP Rasnitsyn & DL Quicke (editors): History of Insects. Springer Verlag, 2nd ed. 2007. ISBN 140200026X . Preview on Google Books
- ↑ David Grimaldi & Michael S. Engel: Evolution of the Insects. Cambridge University Press 2005. ISBN 0521821495
- ↑ SP Yanoviak, M. Kaspari, R. Dudley (2009): Gliding hexapods and the origins of insect aerial behavior. Biology Letters 5: 510-512 doi : 10.1098 / rsbl.2009.0029 .