Thoracopteridae
| Thoracopteridae | ||||||||||||
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Thoracopterus magnificus fossil in the Bergamo Natural History Museum |
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| Temporal occurrence | ||||||||||||
| Ladinium (Middle Triassic) to Carnian (Upper Triassic) | ||||||||||||
| 242 to 228 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Thoracopteridae | ||||||||||||
| Griffith , 1977 | ||||||||||||
The Thoracopteridae are an extinct fish family from the subclass of the Neuflosser (Neopterygii), which occurred in the lower and middle Triassic in the tropical surface regions of the Palaeotethys . Like the recent flying fish (Exocoetidae), the Thoracopteridae were capable of gliding.
features
Like the flying fish, the Thoracopteridae had a pair of enormously enlarged pectoral fins and an asymmetrical, deeply forked caudal fin with a significantly longer lower lobe. Similar to the advanced flying fish of the subfamily Cypselurinae , their pelvic fins were enlarged, so that the animals were "four-winged". With the exception of Thoracopterus , the Thoracopteridae, in contrast to the flying fish, were scaly. The temporal and parietal bones were absent. The pair of frontal bones was laterally widened, as in the case of the flying fish. The jockstrap was almost vertical. The rays of the dorsal and anal fin were only segmented in the distant section; their number corresponded to the number of fin carriers . The anal fin was largely regressed, its fin carriers reduced.
Since the flying fish need water temperatures of 20 ° C and above for their active lifestyle, this is also assumed for the Thoracopteridae.
Systematics
Despite the external similarity, the Thoracopteridae are not related to the recent flying fish that first appeared in the Eocene . Rather, their sliding ability has developed convergent to each other twice. The American ichthyologist Joseph S. Nelson assigned the Thoracopteridae in his standard work Fishes of the World to the Perleidiformes . In their description of the Chinese thoracopterid Potanichthys , which for the first time enabled a more precise cladistic analysis by preserving parts of the neurocranium, Guang-Hui Xu and colleagues were unable to assign the group to either the Perleidiformes or the Luganoiiformes , but they found clear indications for the position of the Thoracopteridae in the stem group of the Neuflosser (Neopterygii). The Thoracopteridae are more basal than the Luganoiiformes but more advanced than the Peltopleuriformes.
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| The external and internal systematics of the Thoracopteridae. Three genera had been described up to 2012. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
literature
- Joseph S. Nelson : Fishes of the World. 4th edition. John Wiley & Sons, Hoboken NJ 2006, ISBN 0-471-25031-7 .
- Guang-Hui Xu, Li-Jun Zhao, Ke-Qin Gao & Fei-Xiang Wu: A new stem-neopterygian fish from the Middle Triassic of China shows the earliest over-water gliding strategy of the vertebrates. In: Proceedings of the Royal Society. doi : 10.1098 / rspb.2012.2261 .