Dinosaurs A to Z
Spinosauridae

Spinosaurus aegyptiacus SPINE-oh-SOR-us

"Spine lizard"

Spinosaurus silhouette
You 1.8 m (5.9 ft) tall
Spinosaurus 15 m (49 ft) long
as long as 9 people standing fingertip to fingertip
silhouette · Alessio Ciaffi (CC-BY) via PhyloPic
Length
15 m (49 ft) — About 15 m long, ~7 tonnes — the longest theropod known.
Period
Late Cretaceous (99–93 Mya)
Place
Africa · Morocco · Egypt
Food
Piscivore (fish-eater) — Mostly fish — including giant sawfish and lungfish from North African rivers.
Clade
Spinosauridae Dinosauria Saurischia Theropoda Crocodile-snouted fish-eaters with sail or hump.

A sail-backed, crocodile-snouted giant of Cretaceous North Africa that fished for its food.

Spinosaurus is the strangest theropod ever found. Long crocodile-shaped jaws, a giant sail down its back, short hind legs, paddle-like tail — almost everything about it points to a life spent in the water. The original skeleton was destroyed in WWII, and for decades artists had to guess what it looked like. New finds in Morocco rewrote almost everything in the 2010s.

More about Spinosaurus

Discovery

Named by German palaeontologist Ernst Stromer · 1915 · Egypt (the type species S. aegyptiacus is mainly known from the Bahariya Formation in Egypt and the Kem Kem beds in Morocco)

The genus was first known from Egyptian remains discovered in 1912 and described by Ernst Stromer in 1915. The original remains were destroyed in World War II, but additional material came to light in the early 21st century.

The text states Spinosaurus is a genus of spinosaurid theropodA mostly meat-eating, bipedal dinosaur. Birds are living theropods. but does not give a translation of the name or its language origin.

Portrait of Ernst Stromer
Ernst Stromer German palaeontologist who described Spinosaurus in 1915 and named the family Spinosauridae for it, placing it in its own cladeA branch of the tree of life: an ancestor and all of its descendants. of theropods because of its unique teeth, vertebrae, and jaw.
Did Spinosaurus mostly hunt in water or on land?
The text says it is unclear whether Spinosaurus was primarily a terrestrial predator or a piscivore (fish eater), pointing to its elongated jaws, conical teeth, and raised nostrils. It may have been a generalized, opportunistic predator biased toward fishing, possibly a Cretaceous equivalent of a large grizzly bear, that also scavenged and took small to medium-sized prey.
For the curious → How might it have sensed prey it could not see?
In 2009, Dal Sasso and colleagues used X-ray computed tomography on the MSNM V4047 snout. Because foramina on the outside all communicated with a space inside the snout, the authors speculated that Spinosaurus may have had pressure receptors that let it hold its snout at the water surface to detect swimming prey without seeing them.

What we know

  • Long, narrow, crocodile-like jaws full of conical teeth — built for catching fish.
  • Tall neural spines on the back formed a sail nearly 2 m tall.
  • Tail had tall fin-like neural spines, suggesting use as a propulsive paddle.
  • Original skeleton destroyed in the 1944 Munich bombing; later finds restored knowledge.

What we guess

  • How much time it spent in water vs. on land. 2014 and 2020 studies argue for semi-aquatic life; some 2022 work pushes back.
  • What the sail was for — display, heat regulation, sexual selection, or all three.
  • Whether it swam mainly by tail propulsion or by punting along the bottom.