The ancient world of dinosaurs often brings to mind images of immense, towering creatures. While many dinosaurs reached colossal proportions, their diversity spanned from the gigantic to surprisingly diminutive forms. This leads to an intriguing question: what was the smallest dinosaur ever discovered? Pinpointing this reveals a fascinating aspect of paleontological research and the incredible variety of life that existed millions of years ago.
Compsognathus: The Current Titleholder
For many years, Compsognathus has held the distinction of being the smallest known non-avian dinosaur. This bipedal carnivore lived approximately 150 million years ago, during the Tithonian age of the Late Jurassic period, in what is now Europe. Its name, derived from Greek, means “elegant jaw,” referring to its slender skull and delicate features.
Compsognathus was a lightly built animal with long legs and a long tail that provided balance during movement. While early interpretations described it as “chicken-sized” based on a smaller German specimen, a larger French fossil revealed an adult size of about 1.25 to 1.4 meters (4 feet 1 inch to 4 feet 7 inches) and a weight between 2.5 to 3.5 kilograms (5.5 to 7.7 pounds). The German specimen, measuring around 70-75 centimeters (28-30 inches) and weighing 0.32-0.58 kilograms, is now believed to be a juvenile.
Fossils of Compsognathus were first discovered in the 1850s in Germany, with a second, larger specimen found in France more than a century later in 1971. These remarkably well-preserved fossils, found in ancient lagoon deposits, have provided insights into its life. Its diet primarily consisted of small, agile lizards, with remains found in stomach cavities indicating it swallowed prey whole. Possessing sharp, pointed teeth, swift movements, and bird-like features like hollow bones and a flexible neck, Compsognathus was an active predator.
How “Smallest” is Determined
Determining the “smallest” dinosaur is a complex scientific endeavor, as the term can refer to length, height, or weight, and fossil records are often incomplete. Paleontologists rely on various methods to estimate the size of extinct animals, primarily by studying fossilized bones. This process involves careful measurement of skeletal elements and comparison with the anatomy of living animals and more complete dinosaur skeletons.
A significant challenge arises when dealing with juvenile specimens, which are naturally smaller than adults. To accurately determine a species’ typical size, scientists focus on identifying and analyzing adult fossils. The completeness of a fossil is also crucial; a more intact skeleton provides a reliable basis for size estimation than fragmentary remains. Skeletal reconstruction, inferring missing parts based on related species, helps visualize a dinosaur’s full dimensions.
Weight estimation often involves volumetric methods, where a digital or physical model of the animal is created and then scaled based on bone density. While these methods provide valuable insights, they inherently involve a degree of uncertainty, and estimates can be refined as new fossils are discovered and analytical techniques improve. The ongoing nature of paleontological discovery means that the title of “smallest” could potentially change with future finds.
Other Noteworthy Small Dinosaurs
Beyond Compsognathus, several other small dinosaurs are notable for their diminutive stature. Lesothosaurus, an early ornithischian dinosaur, lived during the Early Jurassic period, about 176 to 201 million years ago. This bipedal herbivore measured approximately 0.9 to 2 meters (3 to 6.6 feet) in length and weighed around 10 to 20 kilograms (22 to 44 pounds). Its long, slender legs suggest it was a swift runner, and it had a small, flat-faced skull with leaf-shaped teeth for processing vegetation.
Epidexipteryx, discovered in China, is another exceptionally small dinosaur, known for its unique ornamental feathers. This non-avian theropod, dating to the Middle or Upper Jurassic, was only about 25 centimeters (10 inches) in body length, with its distinctive ribbon-like tail feathers extending its total length to about 44.5 centimeters (17.5 inches). It weighed approximately 164 grams (0.36 pounds). Despite its close relation to birds, Epidexipteryx lacked wing feathers for flight, using its tail feathers primarily for display.
Anchiornis, from the Late Jurassic of China, is a small, feathered dinosaur closely related to birds. Roughly the size of a crow, it had a body length of about 30 to 62 centimeters (12 to 24 inches) and an estimated weight between 0.11 to 1 kilogram (0.24 to 2.2 pounds). It possessed long, feathered forelimbs and hind limbs, giving it a “four-winged” appearance, though its feathers were likely not adapted for strong flight. Its bird-like features provide insights into the evolution of flight and feathers in dinosaurs.