Saurocephalus
Encyclopedia
Saurocephalus is an extinct genus of fishes within the family Saurodontidae Cope, 1871.
Members of this family (saurodontids) were teleostean fishes restricted to the upper Cretaceous
. They are placed within the Ichthyodectiformes, an extinct order of fish known from the middle Jurassic
to the late Cretaceous with species found in almost every continent of the world.
From among the almost 20 genera included in the order, saurodontids are more closely related to Gillicus, Xiphactinus
, and Ichthyodectes
.
Saurodontidae currently includes three genera, Saurodon
, Saurocephalus, and Prosaurodon. Members of the three genera were first collected from the upper Cretaceous Western Interior Sea of North America (Niobrara Formation). Consequent finds from elsewhere around the globe indicated saurodontids had a much wider geographical distribution including Europe and the Middle East where some of the best preserved and complete specimens come from the latest Maastrichtian of Jordan . Apparently, the three genera occurred at different time intervals. While the oldest might have been Saurodon known to occur as early as the late Coniacian
, the youngest is Saurocephalus which first appeared during the early Campanian
and continued on to the latest Maastrichtian
.
Although saurodontids were geographically widely distributed and continued until the end of the Cretaceous, they remained only moderately taxonomically diversified. Among the intriguing characters of saurodontid fishes which clearly distinguish them is the toothless unpaired bony predentary
that projected from the lower jaw giving the fish a very characteristic appearance.
The genus Saurocephalus is almost entirely represented by fragmentary specimens with the exception of a single complete and superbly well preserved specimen collected from latest Maastrichtian deposits of Jordan, Saurocephalus longicorpus . The complete material from Jordan offered an extensive amount of valuable information about Saurocephalus . With an elongate, torpedo-like body, saurocephalids were extremely fast open water formidable ambush predators. The morphology of their teeth and jaw structure suggest they were meat eaters. 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. Saurocephalids were powerful and ferocious predators with powerful jaws capable of slicing and biting off large chunks of meat from their potential prey items. No doubt, fish was on top of the diet list. The large sizes attained by some saurocephalids which exceed two meters in length, may indicate they were capable of handling larger prey items such as smaller marine reptiles and sharks. To process large prey, they would cut them into smaller more manageable pieces using their powerful large jaws and sharp teeth. A close modern analogue of saurocephalids and to the matter saurodontids, would be barracuda
s (Sphyraena barracuda) 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 to saurocephalids.
Members of this family (saurodontids) were teleostean fishes restricted to the upper Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
. They are placed within the Ichthyodectiformes, an extinct order of fish known from the middle Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
to the late Cretaceous with species found in almost every continent of the world.
From among the almost 20 genera included in the order, saurodontids are more closely related to Gillicus, Xiphactinus
Xiphactinus
Xiphactinus was a large, 4.5 to 6 m long predatory bony fish that lived in the Western Interior Sea, over what is now the middle of North America, during the Late Cretaceous. When alive, the fish would have resembled a gargantuan, fanged tarpon...
, and Ichthyodectes
Ichthyodectes
Ichthyodectes ctenodon was a 4-metre long ichthyodectid. It lived in the Western Interior Seaway during the late Cretaceous. It was closely related to the 4 to 6 metre long Xiphactinus audax, and the 2-metre long Gillicus arcuatus, and like other ichthyodectids, I. ctenodon is presumed to have...
.
Saurodontidae currently includes three genera, Saurodon
Saurodon
Saurodon is an extinct genus of Ichthyodectid fish from the Cretaceous.Saurodon leanus is known to occur as early as the late Coniacian through the Santonian, in the Late Cretaceous.- Species :...
, Saurocephalus, and Prosaurodon. Members of the three genera were first collected from the upper Cretaceous Western Interior Sea of North America (Niobrara Formation). Consequent finds from elsewhere around the globe indicated saurodontids had a much wider geographical distribution including Europe and the Middle East where some of the best preserved and complete specimens come from the latest Maastrichtian of Jordan . Apparently, the three genera occurred at different time intervals. While the oldest might have been Saurodon known to occur as early as the late Coniacian
Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...
, the youngest is Saurocephalus which first appeared during the early Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
and continued on to the latest Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
.
Although saurodontids were geographically widely distributed and continued until the end of the Cretaceous, they remained only moderately taxonomically diversified. Among the intriguing characters of saurodontid fishes which clearly distinguish them is the toothless unpaired bony predentary
Predentary
The predentary is an 'extra' bone in the front of the lower jaw, which extended the dentary . It is found in the fossilised remains of ornithischian dinosaurs, which were herbivorous. The predentary coincided with the premaxilla in the upper jaw. Together they formed a beak-like apparatus used to...
that projected from the lower jaw giving the fish a very characteristic appearance.
The genus Saurocephalus is almost entirely represented by fragmentary specimens with the exception of a single complete and superbly well preserved specimen collected from latest Maastrichtian deposits of Jordan, Saurocephalus longicorpus . The complete material from Jordan offered an extensive amount of valuable information about Saurocephalus . With an elongate, torpedo-like body, saurocephalids were extremely fast open water formidable ambush predators. The morphology of their teeth and jaw structure suggest they were meat eaters. 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. Saurocephalids were powerful and ferocious predators with powerful jaws capable of slicing and biting off large chunks of meat from their potential prey items. No doubt, fish was on top of the diet list. The large sizes attained by some saurocephalids which exceed two meters in length, may indicate they were capable of handling larger prey items such as smaller marine reptiles and sharks. To process large prey, they would cut them into smaller more manageable pieces using their powerful large jaws and sharp teeth. A close modern analogue of saurocephalids and to the matter saurodontids, would be barracuda
Barracuda
The barracuda is a ray-finned fish known for its large size and fearsome appearance. Its body is long, fairly compressed, and covered with small, smooth scales. Some species could reach up to 1.8m in length and 30 cm in width...
s (Sphyraena barracuda) 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 to saurocephalids.