| Name | Ichthyovenator | Diet | Piscivorous |
| Name Meaning | Fish Hunter | Height | 2.95 meters (9.7 feet) |
| Pronunciation | Ich-thee-oh-van-nah-tor | Length | 8.5 to 10.5 meters (27.8 to 34.4 feet) |
| Era | Mesozoic – Early Cretaceous | Weight | 2 to 2.4 tonnes (2.2 to 2.6 short tons) |
| Classification | Dinosauria, Saurischia, Theropoda | Location | Laos, Asia |
Ichthyovenator Pictures
The Ichthyovenator
The Ichthyovenator was a spinosaurid dinosaur, which means it was a large bipedal creature with a crocodilian-like skull.
While most spinosaurids had one sail on their backs, the sail of an Ichthyovenator was divided into two sails that took the shape of a wave.
This is by far the most distinctive characteristic of the genus!
The only species in the genus, Ichthyovenator laosensis, is often called “fish hunter,” indicating that it feeds primarily on aquatic prey.
Unlike other dinosaurs, the Ichthyovenator is a relatively recent discovery, as the first fossils belonging to the genus were found in 2010 in the Grès supérieurs Formation in Laos, Asia.
Paleontologists estimate that the creature roamed the Earth during the Early Cretaceous.
It lived around 125-113 million years ago, during the Aptian age.
Since the discovery of this species is among the first confirmations that spinosaurids lived in Asia, it’s of the essence to discuss its appearance, behavior, and history.
Keep reading to discover more!
Physical Characteristics
If we were to compare the Ichthyovenator with other spinosaurids, we’d say it was a pretty small dinosaur.
Compared to human size, however, the dinosaurs were enormous!
Scientists estimate that the Ichthyovenator measured approximately 8.5-10.5 meters (27.8-34.4 feet) long, 2.95 meters (9.7 feet) tall at the hips, and weighed roughly 2-2.4 tonnes (2.2-2.6 short tons).
Take Spinosaurus, for instance, another member of the spinosaurid family.
Some scientists estimate that this dinosaur measured around 14.9 meters (49 feet) long, although others suggest that some specimens might’ve reached 15.8-18 meters (52-59 feet) long.
Oxalaia is another genus in the Spinosauridae family.
This dinosaur is believed to have reached a length of approximately 11.8-14 meters (39-46 feet).
As such, it’s safe to presume that the Ichthyovenator is among the world’s smallest spinosaurids.
However, this doesn’t mean there’s no uniqueness to it! Some facts about the species will undoubtedly surprise you!
First, the Ichthyovenator is most renowned because the sail on its back was divided in half.
To get rid of technical details, a sail consists of vertebrae neural spines, a protrusion from an animal’s back.
As such, while other spinosaurids had only one complete sail, which rose to a peak and then went down, the dinosaur we’re discussing today had its sail cut in half, thus taking the shape of a wave, or, in scientific terms, a sinusoid curvature.
In fact, since the discovered fossils were primarily vertebrae, ilia, and pubic bones, most research papers discussing the Ichthyovenator focus on these.
One study shows that the 12th dorsal vertebra belonging to an Ichthyovenator is among the most unusual and bizarre theropod vertebrae and has been the subject of many scientific papers.
However, since these fossils reveal information of interest more to scientists than enthusiasts, we won’t get into too many details.
Here’s what we can share instead:
- The Ichthyovenator probably had a long, shallow snout.
- Its forelimbs were likely very short but strong, while the hind limbs were robust and longer.
- It is believed the species had long claws as well.
- Its head probably resembled that of a crocodile.
- The teeth were conical and straight and featured no serrations, which served as a turning point in the process of naming the species.
- The ilium of the pelvis measured around 92 centimeters (36.2 inches) long and had a blade-like shape; this indicates it was probably the longest-known ilium among theropod species.
- The long tail featured tall tail spines that might have helped during swimming.
However, it’s of the essence to note that since no skull and limb fossils were found, the details on these aspects are purely suggestions based on fossils belonging to other spinosaurids.
Habitat and Distribution
Ichthyovenator fossils were recovered from a territory we now call Laos.
More precisely, they were found in the Grès supérieurs Formation of the Savannakhet Basin, which had strata dating back to the Early Cretaceous.
Very little is known about this formation, except that it’s considered an equivalent to Thailand’s Khok Kruat and Phu Phan Formations.
Based on this, we can assume that the Grès supérieurs Formation was a fluvial formation consisting of sandstone, mudstone, and siltstone.
Unfortunately, more information is needed about the climate of the habitat the Ichthyovenator called home.
However, since the dinosaur was probably semiaquatic and its tail spines support that, at least we know that it lived close to water sources.
Behavior and Diet
Spinosaurids, the Ichthyovenator included, are thought to have had a semiaquatic lifestyle.
This conclusion is backed up by the unique morphology of their skull, dentition, neural spines, and tail spines.
The fact that their diet is thought to have been pretty diverse further supports this assumption.
However, whether they could partially or completely submerge underwater is uncertain, as this would imply that they could also breathe underwater.
That’s why researchers believe that the dinosaurs were primarily terrestrial and only waded and dipped into water for feeding purposes.
But if this is true, what was the role of the Ichthyovenator tail spines?
They were thought to have served as an aid for propulsion through the water.
Whether this is true or not, it should yet be discovered. As you can see, we’re oscillating between contradictions here!
Here’s another mystery: how did the Ichthyovenator use its forelimbs?
While scientists are somewhat certain that the elongated, narrow snouts were used to catch food (primarily aquatic prey) just like modern crocodilians, they aren’t as sure whether the short forelimbs helped in the process.
However, some specialists suppose they worked well in scratch-digging and hook-and-pull digging.
As for what prey the Ichthyovenator went for, this remains a partial mystery as well.
While it has been confirmed that jaw and tooth morphology resembles that of other fish-eating predators, the size and type of the prey are subject to debate.
Some studies confirm that its physiology was likely adapted only for small prey.
Furthermore, specialists are still debating whether the Ichthyovenator was solely piscivorous.
Life Cycle
Studies show that the Ichthyovenator might’ve relied on its sail for courtship displays while attracting mates.
It might have played an important role in sexual selection as well.
Another hypothesis concerning the role of the Ichthyovenator spine says that these dinosaurs might’ve used the unique shape of their sails to recognize members of their species.
As for the reproductive process, very little is known about this particular species.
However, since the Ichthyovenator was a theropod, we can outline some assumptions based on what scientists know about theropods and dinosaurs in general.
Here’s what we discovered about the theropod reproductive system:
- Male theropods are known to have possessed a retractable penis and internal testes.
- Females are known to have possessed paired ovaries and oviducts. They also had a system for storing mature eggs similar to those of crocodilians.
- They reproduced by laying eggs through the cloaca; the eggs were laid in pairs.
- Some theropods are known to incubate eggs.
- The incubation period was about 60-90 days.
- Most baby dinosaurs were precocial.
Based on the above details, we can suppose that the reproductive process of the Ichthyovenator was similar.
Naturally, some things aren’t set in stone. For example, it’s unknown what type of nests this particular species used and whether the eggs were incubated.
We can only hope that future discoveries will shed some light on the Ichthyovenator life cycle and reproduction.
Evolution and History
Spinosaurids are part of the Tetanurae clade, which includes most theropods.
The members of this clade are closely related to modern birds.
Since the Aves class descends from Tetanurae, and spinosaurids are part of the same clade, we can safely state that the spinosaurid, Ichthyovenator included, is an ancestor of modern birds.
The year 1820 marked the discovery of the first spinosaurid fossil – a single conical tooth.
It was found in the Wadhurst Clay Formation.
At first, scientists assumed it belonged to a crocodile specimen, naming it Suchosaurus, which translates as “crocodile lizard.”
Only in 1998 was it accepted that the previously discovered fossils belonged to a spinosaurid.
Over the years, paleontological expeditions revealed that spinosaurids were widely distributed, having lived in Europe, Africa, Asia, and South America.
The discovery of the Ichthyovenator is often considered the first official confirmation that spinosaurids lived in Asia.
Although two other dinosaurs had been previously discovered (Siamosaurus and Sinopliosaurus fusuiensis), their validity is still widely debated.
The first fossils belonging to this genus were discovered in 2010 in Savannakhet Province, Laos.
They included several vertebrae, both ilia, both ischia, a right pubic bone, and a posterior dorsal rib.
Only two years later, specialists attributed the discovered fossils to the Spinosauridae family and the Baryonychinae subfamily.
Two other years later, Ronan Allain discovered that the Ichthyovenator lacked the teeth serrations found in Baryonychinae specimens and “moved” it to the Spinosaurinae subfamily.
Another recent hypothesis about the species was proposed by an American paleontologist who suspected it was a carcharodontosaurid related to the Concavenator, but this has received no confirmation.
Interactions with Other Species
Paleontological research revealed that the Ichthyovenator might’ve shared its habitat with the following creatures:
- Sauropods like Tangvayosaurus
- Iguanodontians
- Neoceratopsians
- Other theropods
- Ornithopods
- Ray-finned fish like lepidotes and Lanxagichthys
- Unknown species of carettochelyid and trionychid turtles
- Turtles like Xinjiangchelys and Shachemys
- Trigoniid bivalves like Plicatounio and Tridonioides
Since the Ichthyovenator is believed to have been primarily piscivorous, it’s highly likely that it didn’t actively seek confrontations with other dinosaurs like carnivorous predators do.
However, we cannot exclude interspecific combat if food sources were scarce.
Moreover, since the dinosaurs known to have inhabited that same ecosystem were herbivorous, the Ichthyovenator probably had no natural predators.
Cultural Significance
Although the Ichthyovenator is included in many books about dinosaurs, it’s undoubtedly not as popular as other dinosaurs – the Stegosaurus, for example, which appears in dozens of books, movies, and games.
However, the fish hunter does appear in the Jurassic World: Primals Ops game, although it is wrongly depicted as being part of the Baryonychinae subfamily.
The species is now part of the Jurassic World: Dominion toy line; more precisely, it appeared in the “Roar Strikers” assortment.
It can also be seen in a game called Prior Extinction, where it’s depicted as a slow-moving dinosaur capable of underwater bursts of speed.
Furthermore, the Ichtyovenator also appears in Additional Creatures 2: Wild ARK, where it’s considered an excellent aquatic fighter.
Nonetheless, while the species isn’t too famous in popular culture, it has aroused the interest of scientists from around the world, especially due to the bizarre form of its vertebrae and the back sail that appears to be slightly “cut in half.”
Conclusion
The Aptian age of the Early Cretaceous “hosted” a fish-hunting dinosaur – the Ichthyovenator!
Although the genus was named relatively recently, and many fossils are missing for a somewhat complete skeleton, scientists put in the effort and discovered much about it!
Thanks to their research, we know that the fish-eating creature with two sails on its back lived around 125-113 million years ago.
It was probably semiaquatic, although its swimming behavior is still up for debate.
It was small compared to other spinosaurids but enormous compared to other prehistoric animals!
The Ichthyovenator likely had small but strong forelimbs and long, robust hind limbs.
Moreover, the spines on its tail are thought to have aided in propulsion through water.
Needless to say, the discovery of the Ichthyovenator represented a major contribution to our world’s evolutionary history since it’s now considered the first official confirmation that Asia served as the home for spinosaurids.
Hopefully, future paleontological discoveries will facilitate a full Ichthyovenator reconstruction, thus shedding light on other aspects of its evolution and history.
Sources:
- https://en.wikipedia.org/wiki/Ichthyovenator
- https://qmro.qmul.ac.uk/xmlui/bitstream/handle/123456789/49404/Hone%20A%20Century%20of%20Spinosaurs%202017%20Accepted.pdf?sequence=1&isAllowed=y
- https://en.wikipedia.org/wiki/Tetanurae
- https://blogs.scientificamerican.com/tetrapod-zoology/species-recognition-vs-sexual-selection-in-dinosaurs/
- https://link.springer.com/article/10.1007/s00114-012-0911-7
- https://www.google.com/books/edition/Dinosaur_Ultimate_Handbook/Oms4EAAAQBAJ?hl=en&gbpv=1&dq=ichthyovenator&pg=PT245&printsec=frontcover
- https://www.researchgate.net/profile/Ronan-Allain/publication/224820891_The_first_definitive_Asian_spinosaurid_Dinosauria_Theropoda_from_the_Early_Cretaceous_of_Laos/links/0046351e7a3eb754b4000000/The-first-definitive-Asian-spinosaurid-Dinosauria-Theropoda-from-the-Early-Cretaceous-of-Laos.pdf
- https://www.researchgate.net/profile/Ronan-Allain/publication/249968651_Allain_et_al_2012_Ichthyovenator_SI/links/00b4951e7a49f6d1d9000000/Allain-et-al-2012-Ichthyovenator-SI.pdf
- https://www.researchgate.net/profile/Ronan-Allain/publication/249968651_Allain_et_al_2012_Ichthyovenator_SI/links/00b4951e7a49f6d1d9000000/Allain-et-al-2012-Ichthyovenator-SI.pdf
- https://www.researchgate.net/publication/312976683_The_dinosaur_fauna_from_the_Khok_Kruat_Formation_Early_Cretaceous_of_Thailand
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