Dilophosaurus

Credit: Joanna Kobierska.

*Dilophosaurus* is an extinct genus of theropod dinosaur that lived during the Early Jurassic of what is now North America.

## Description

*Dilophosaurus* had a large and robust skull with two head crests curving inwards. Experts don't know what the head crests of *Dilophosaurus*, some think the head crests served as display, while others think it related to temperature regulation. *Dilophosaurus*, despite the common image, had no evidence of venom and was 5 feet tall. The crests were hollow like bird crests, only having a criss-cross of thin bone supports to strengthen them.

    *Dilophosaurus* was likely covered in full, if not a partial coat of light feathering. A trace fossil of *Dilophosaurus*' cloaca, arms and tail, demonstrated the sitting position of theropod dinosaurs: arms and tail flat on the ground with legs bent. Only the ankle down laid at rest and the body had an upright posture. The trace fossil also had trace feathers around the animals crotch and lower tail regions.

New evidence suggests that the curved upper jaw and narrow snout are both adaptations for a piscivorous diet. The indent in the jaw my have been used for getting a grip on fish, and sometimes even small animals. Some speculate that *Dilophosaurus* may have had nasal or throat sacs.  The nasal sacs could have been used to make load sounds. *Dilophosaurus* has long teeth at the base of its jaws, meaning that it had suitable adaptations for a piscivorous and macropredatory lifestyle; slender jaws able to catch and hook onto fast moving/slippery prey.

*Dilophosaurus*' crests were likely for sexual dimorphism and display. Several hypothesis on the usage of the twin crests range from temperature regulation to decorative only.

    The most prevailing theory says that the crests were either used as sexual dimorphism (females may have lacked them, though it is still unclear), and may have had vibrant colors on them. The crests only reached full size when the animals hit sexual maturity, a reason why some specimens have lower crests, and other higher crests.

## Classification

*Sinosaurus* and *Dracovenator* were close relatives of *Dilophosaurus*, within Neotheropoda. *D. sinensis* is identical *Sinosaurus triassicus*, possibly erecting a new species; *S. sinensis*.

## Paleobiology

Meanwhile despite generally depicted as a carnivore; the high potential for a more varied diet; fish, in addition to normal prey items has been recently established by paleontologists.  Whereas Some paleontologists have interpreted that *Dilophosaurus* could be more derived compared to regular theropods.

Latest research has put the possibility that *Dilophosaurus* could be potential macropredators of their time . Dilophosaurus might have wandered the Early Jurassic landscapes, hunting for small animals and fish. Studies suggest *Dilophosaurus* did not have a strong bite force, based on weakness on the subnarial gap. Both theories remain intact, although based on fossil bitemarks evidence found on prosauropod remains might indicate the generalist predator interpretation could be more valid. A 2022 study using results from a physics class finds that a *Dilophosaurus* (if placed in a 100-meter-sprint with Usain Bolt) would have lost by 2 seconds, based on biomechanics and physics.

## Gallery

### Reconstructions

**Credit: Gabriel Ugueto.****Credit: Chase Stone.****Credit: aberrantologist.**
## References

1. ↑ https://en.wikipedia.org/wiki/Dilophosaurus
2. ↑ https://twitter.com/anomallite/status/1280972846806622209/photo/1, speculation of Dilophosaurus soft tissues.
3. ↑ https://www.cambridge.org/core/journals/journal-of-paleontology/article/comprehensive-anatomical-and-phylogenetic-evaluation-of-dilophosaurus-wetherilli-dinosauria-theropoda-with-descriptions-of-new-specimens-from-the-kayenta-formation-of-northern-arizona/39C2921EDC6E951AC9F94A22158CA4E5
4. ↑ http://files.geology.utah.gov/surveynotes/articles/pdf/fishing\_dinos\_39-3.pdf
5. ↑ https://www.nationalgeographic.com/science/2020/07/jurassic-park-got-almost-everything-wrong-about-iconic-dinosaur-dilophosaurus/
6. ↑ https://aapt.scitation.org/doi/10.1119/5.0041057