Name Meaning: Heavy Claw Location Found: Weald Clay, Southeast England (Hastings Subgroup)

buy mydriacyl without prescription Geologic Era: Early Cretaceous

Antelope Estimated Range: Southeast England, with possible remains also found in Spain and Portugal

Size: 7.5 meters (about 25 feet) long

Extinction Date: Early Cretaceous

Our representation of Baryonyx is a section of a limb bone. As is typical with theropods, the interior is hollow (see probably Acheroraptor limb element for similar structure). I am not certain if this fragment came from a juvenile or an adult. After looking at diagrams of the forelimb for both Baryonyx and Suchomimus, I do not think the bone section is from the forelimb. Suchomimus is likely very closely related to Baryonyx, so using the two skeletons for comparison is fair, I think. The forelimb elements of both Baryonyx and Suchomimus are rather robust, which does not match up well to the structure of our fragment. The hindlimb for both species, however, has a bit more of a gracile look to it. If the fragment came from an adult, my closest identification would be a section of a femur.


The original name for the likely former owner of this bone would have been Suchosaurus. Aside from an as-yet undescribed theropod, Suchosaurus is the only conclusively identified large predator from the area. This animal was first describe in 1842, and spent the next century and a half being classified as either a dinosaur or crocodile. Incidentally, spinosaurid animals (such as Baryonyx and Suchosaurus) have skulls that look somewhat crocodilian. However, Suchosaurus remains are very scant; the holotype consists of a few teeth and a part of a mandible. These remains, as it turns out, match up very well to Baryonyx, which is known from much more complete remains. Several paleontologists have chosen to reclassify Suchosaurus as Baryonyx, which I think is a logical action.

Cast of thumb claw
Partial jaw with tooth sockets (crack is due to a break in transit)
Rib Fragment

Another interesting feature of Baryonyx and its relatives are the very robust forelimbs. Most large predators of the time had forelimbs that were reduced in size (see Unidentified Abelisaurid for an extreme depiction of this phenomenon). It was hypothesized that Baryonyx and its spinosaurid relatives were primarily quadrupeds, which would be very unusual for theropod dinosaurs. Tests using biomechanical models showed that while Baryonyx’s arms were strong enough to support its body mass in a quadupedal stance, it more than likely did not spend the majority of its time that way. However, this posture would have been very useful for crouching by a river or lake and hunting for fish. The strong arms were probably used to tear apart larger fish and prey items.

Tooth Cast

Baryonyx would have shared its environment with sauropods, iguanadontids, and armored thyreophorans. Just because Baryonyx primarily hunted fish did not mean these other animals were necessarily safe, however. The holotype specimen for Baryonyx was found with partial remains of a juvenile Iguanodon in its stomach area, so it is a safe assumption that Baryonyx, like any other predator, would not turn down an easy meal.

Partial caudal centrum (repaired because SOMEONE in shipping used the box for a soccer ball…pray I never figure out who you are)

Having a specialized diet would have helped reduce interspecific competition between large predators. If Baryonyx kept itself primarily to eating fish, it could have shared its territory with other large predators with little problems. A similar scenario existed in Africa between Spinosaurus and Carcharodontosaurus. Both animals were comparable in size, though probably lived in different areas (Spinosaurus near rivers and Carcharodontosaurus in the woodlands). Baryonyx did have a few other sizable carnivores in its area, among them a megalosaurid type dinosaur. It would be interesting to learn if Irritator, a South American spinosaurid, had a similar ecological niche to Baryonyx. As of yet, no other large theropods have been found in the vicinity of where Irritator was discovered, but that does not mean they weren’t there.

Image Credits:

Skeleton: By Ripton Scott from Wimbledon, United Kingdom – by FunkMonk, CC BY-SA 2.0,

Reconstructed Animal: By Lineart by Robinson Kunz ( by Rebecca Slater ( –, CC BY-SA 3.0,