Psarolepis
| Psarolepis Temporal range:
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|---|---|
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| Psarolepis romeri | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Superclass: | Osteichthyes |
| Genus: | †Psarolepis Yu, 1998 |
| Species: | †P. romeri
|
| Binomial name | |
| †Psarolepis romeri Yu, 1998
| |
Psarolepis (
Description
Psarolepis had a pair of 'parasymphysical tooth whorls', teeth which extend up at the front of the
The pock-marked head of Psarolepis was made of plates containing a layer of
The most spectacular findings were the fin spines. Two are known: one extending back from the shoulder girdle and another which is associated with the dorsal fin. These fin spines are found only in primitive jawed fishes and are apparently absent from the most primitive sharks, but present in abundance in more derived forms.
Psarolepis had teeth at the very front of the snout with large fangs on the tooth plate. Outstanding feature are the 'parasymphysical tooth whorls' which place the fish in the
Discovery
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Most of the fossils of Psarolepis were discovered at the same locality of the
History and classification
When Psarolepis was described for the first time in 1998, it was placed in the group of sarcopterygians (lobe-finned fishes) because the skull and jaws resemble those of primitive lungfishes. In 1999 Zhu et al. were unable to locate Psarolepis in the cladogram because they did not know if it was the most primitive lobed-finned fish or the most primitive bony fish.
There are some characteristics that bony fish do not have, such as the median spine located behind the head, which is known in
The same year Long re-examined the phylogenetic position of the fish and pointed out several similarities between Psarolepis and Onychodontiform fishes.[5] He also noted that the presence of a rotational tooth whorl combined with the other characteristics in the skull, and possibly in the shoulder girdle, show that Psarolepis is better placed as a sister taxon to Onychodus as the most basal member of the group of Onychodontiforms. Moreover, Long, referring to new fossils collected from Gogo Formation, Western Australia, said that Psarolepis and Onychodus are both basal bony fish and are more primitive than other lobe-finned groups.
References
- Benton, M. J. (2005). Vertebrate Palaeontology. Blackwell Publishing.
- Ahlberg, Per Erik (February 1999). "Palaeontology: Something fishy in the family tree". Nature. 397 (6720): 564–565. S2CID 4312306.
- Ahlberg, Per Erik, ed. (2001). "Interrelationships of basal osteichthyans". Major Events in Early Vertebrate Evolution: Palaeontology, phylogeny, genetics and development. CRC Press.
- Zhu, Min; Yu, Xiaobo; Janvier, Philippe (February 1999). "A primitive fossil fish sheds light on the origin of bony fishes". Nature. 397 (6720): 607–610. S2CID 4429109.
- Yu, Xiaobo (June 1998). "A new porolepiform-like fish, Psarolepis romeri, gen. et sp. nov. (Sarcopterygii, Osteichthyes) from the Lower Devonian of Yunnan, China". Journal of Vertebrate Paleontology. 18 (2): 261–274. .
- Long, John A. (December 2001). "On the relationships of Psarolepis and the onychodontiform fishes". Journal of Vertebrate Paleontology. 21 (4): 815–820. S2CID 86232770.