Ichthyovenator is a spinosaurid dinosaur genus that thrived in the region now known as Laos approximately 125 to 113 million years ago, during the Aptian stage of the Early Cretaceous period. The initial discoveries of this dinosaur were made in 2010 within the Grès supérieurs Formation of the Savannakhet Basin. These fossils comprise a partial skeleton, albeit lacking the skull and limbs.

The name "Ichthyovenator" is derived from the Greek words "ichthyo," meaning "fish," and "venator," signifying "hunter," reflecting its presumed piscivorous (fish-eating) lifestyle. Additionally, the specific name pays homage to the country of Laos.

Subsequent to the initial findings, more remains were unearthed from the same excavation site in 2014. These additional fossils encompassed teeth, further vertebrae (backbones), and a pubic bone belonging to the same individual. The holotype specimen of Ichthyovenator is estimated to have measured between 8.5 to 10.5 meters (28 to 34 feet) in length and weighed approximately 2.4 tonnes (2.6 short tons; 2.4 long tons).

Ichthyovenator's teeth are characterized by their straight, conical shape, lacking serrations. These teeth exhibit distinct front edges on the base of the tooth crown. The rear cervical and front dorsal vertebrae of Ichthyovenator possess articulating surfaces that are wider than they are high, and broader than the length of their centra.

One of the striking features of Ichthyovenator is its sail, a characteristic shared with many spinosaurid dinosaurs. However, Ichthyovenator's sail stands out due to its unique appearance. Unlike its relatives, the sail is divided into two segments over the hips and boasts a sinusoidal, or wave-like, curvature. This feature is distinct from the continuous sails of related genera like Spinosaurus and Suchomimus, or the lower dorsal spines seen in Baryonyx.

Although no skull remains have been recovered for Ichthyovenator, it is consistent with other spinosaurids in having an elongated, low, and narrow snout. This snout structure allowed these dinosaurs to extend their reach for food and snap their jaws shut rapidly, much like modern crocodiles. The tips of their upper and lower jaws flared out to form a rosette-like shape lined with long teeth, creating a natural trap for capturing prey.

Ichthyovenator's straight, unserrated teeth were ideally suited for impaling and capturing small animals and aquatic prey. This dinosaur's diet likely consisted predominantly of aquatic creatures, aligning with its name's etymology. Spinosaurids, including Ichthyovenator, are known to have consumed not only fish but also small dinosaurs and pterosaurs. Additionally, this dinosaur's conspicuous sail may have served purposes such as sexual display or species recognition.

Notably, Ichthyovenator exhibits high neural spines in its tail vertebrae, suggesting that, similar to modern crocodilians, its tail might have aided in swimming.