Pachythrissops

Pachythrissops is an extinct genus of ray-finned fish. It contains two species, P. laevis from the Purbeckian of England and P. propterus from the Tithonian of Germany. A third species, P. vectensis, has been reassigned to the elopiform genus Arratiaelops.^[1] Pachythrissops is often regarded as one of the most primitive members of the order Ichthyodectiformes;^[2] however, a phylogenetic analysis by Cavin et al. (2013) placed it and the related genus Ascalabothrissops outside the group.^[3]

Pachythrissops Temporal range: Tithonian–Berriasian PreꞒ Ꞓ O S D C P T J K Pg N
Fossil of Pachythrissops propterus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	†Ichthyodectiformes (?)
Genus:	†Pachythrissops Woodward, 1919
Species[1]
†P. laevis Woodward, 1919 (Type) †P. propterus (Wagner, 1873)

Sources

1. Taverne, L. (1999). "Ostéologie et position systématique d'Arratiaelops vectensis gen. nov., téléostéen élopiforme du Wealdien (Crétacé inférieur) d'Angleterre et de Belgique" (PDF). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique (in French). 69: 77–96.
2. Arratia, G. (2000). "Remarkable teleostean fishes from the Late Jurassic of southern Germany and their phylogenetic relationships". Fossil Record. 3 (1): 137–179. doi:10.1002/mmng.20000030108.
3. Cavin, L.; Forey, P. L.; Giersch, S. (2013). "Osteology of Eubiodectes libanicus (Pictet & Humbert, ) and some other ichthyodectiformes (Teleostei): phylogenetic implications". Journal of Systematic Palaeontology. 11 (2): 115–177. doi:10.1080/14772019.2012.691559. S2CID 83807640.

• Fossils (Smithsonian Handbooks) by David Ward (Page 215)