Saurocephalus

Saurocephalus Temporal range:
Two jaws ofS. lanciformis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	†Ichthyodectiformes
Family:	†Saurodontidae
Genus:	†Saurocephalus Harlan, 1824
Type species
†Saurocephalus lanciformis Harlan, 1824
Other species
†S. albensisJaccard, 1869 †S. arapahoviusCope,1872 †S. broadheadiStewart, 1898 †S. dentatusStewart, 1898 †S. disparHebert, 1855 †S. fayumensis?Tawadros, 2001 †S. feroxStewart, 1898 †S. inaequalisMünster, 1846 †S. inflexusJaccard, 1869 †S. longicorpusKaddumi, 2009 †S. pamphagusHay,1899 †S. phlebotomus?Cope, 1870 †S. pygmaeusLoomis, 1900 †S. woodwardiDavis, 1878 †S. xiphirostrisStewart, 1898
Synonyms
Daptinus?Cope, 1873 Daptinusphlebotomus?Cope, 1870

Saurocephalus(fromGreek:σαῦροςsaûros,'lizard' andGreek:κεφαλήkephalḗ'head')is an extinct genus ofray-finned fisheswithin the familySaurodontidae.The genus was first described in 1824 and contains six or seven species, including the type speciesS. lanciformis.Saurocephalusfirst appeared during the earlyValanginianand continued on to theMaastrichtian,where it nearly wentextinct.However, the recent discovery ofS. lanciformisremains from the earliestPaleoceneindicates that it just barely survived into theCenozoic.This would make it the last survivingichthyodectiform.

Saurocephalusis almost entirely represented by fragmentary specimens with the exception of a few complete specimens, such as a near-complete specimen of the speciesS. longicorpusfrom Jordan.The complete material from Jordan offered an extensive amount of valuable information aboutSaurocephalus.With an elongate, torpedo-like body,Saurocephaluswas extremely fast and it was probably a formidable open-water ambush predator. The morphology of its teeth and jaw structure suggests it was apiscivore.The closely set very sharp, and firmly anchored teeth lined up along the upper and lower jaws acted together like sharp serrated scissors. The ventral extension of the upper jaw deep unto the sides of the lower jaw made the jaws perform like meat slicers.Saurocephaluswas a powerful and ferocious predator with a powerful jaw capable of slicing and biting off large chunks of meat from its potential prey items - no doubt, fish was on top of the diet list. To process large prey, it would cut them into smaller, more manageable pieces using its large jaws and serrated teeth. A close modern analogue ofSaurocephalusand to the matter,saurodontids,would bebarracudas(Sphyraenabarracuda), known to ambush, ram, and stun their prey using the strong anterior projection of the dentary. Although not as notably elongate, the overall body outline of barracudas is similar toSaurocephalus.

S. lanciformisfossils are known from the earlyDanianof theHornerstown FormationinNew Jersey,indicating that they at least briefly survived theCretaceous-Paleogene extinction event.They appear to have persisted longer into the Danian than other Mesozoic fish that have their youngest records from the formation (Pseudocorax,Ischyodus,Anomoeodus,andEnchodus).