Pterosaurs were flying reptiles that lived during the Mesozoic Era alongside dinosaurs. They are often referred to as “flying dinosaurs” but are not technically dinosaurs. Pterosaurs were the first vertebrates to evolve powered flight. Their wings were formed by membranes of skin that stretched from an elongated fourth finger to the body. With wing spans that could reach over 30 feet, pterosaurs were the largest animals ever to take flight. While birds and bats are the only surviving flying vertebrates today, pterosaurs ruled the skies for over 150 million years before going extinct at the end of the Cretaceous Period.
What Are Pterosaurs?
Pterosaurs were reptiles that evolved the ability to fly. They lived from the late Triassic Period to the end of the Cretaceous Period, from about 228 to 66 million years ago. Pterosaurs are members of the order Pterosauria within the class Reptilia. They are closely related to dinosaurs but are not technically considered dinosaurs.
Pterosaurs had hollow bones, large wing membranes called patagia that stretched from an elongated fourth finger to the body, and other adaptations that enabled powered flight. Their brains and sensory systems were well developed with large optic lobes for good eyesight. Pterosaurs lived in a range of habitats worldwide and exhibited great differences in size and anatomy.
The name “pterosaur” means “winged lizard” and comes from the Greek words pteron meaning wing and sauros meaning lizard. They are often colloquially referred to as “pterodactyls”, however Pterodactylus was just one specific pterosaur genus. There were hundreds of pterosaur genera that lived at various times and places during the Mesozoic Era.
Pterosaur Flight Adaptations
Pterosaurs evolved anatomical adaptations that enabled them to be the first vertebrates capable of powered flight:
– Wings – Pterosaur wings were formed by skin and muscle membranes called patagia that attached to an elongated fourth finger and extended to the body. The wing membranes were strengthened by closely spaced fibers called actinofibrils.
– Lightweight Bones – Pterosaur bones were hollow and air-filled, making their skeletons lightweight and ideal for flight. Their bones were thin-walled, with reinforcing struts for strength.
– Large Chest Muscles – Powerful flight muscles attached to an enlarged breastbone helped pump the wings up and down to generate the aerodynamic force needed for flight. The hindlimbs also helped propel the wings.
– Modified Limbs – Their forelimbs became modified wing structures. Their fourth finger was greatly elongated to give the wing support. The other three fingers were small with claws used for hanging and climbing. Their hindlimbs became slender and their feet evolved specialized gripping pads.
– Aerodynamic Head Crests – Many pterosaur species evolved elaborate head crests that may have helped stabilize and steer their flight by acting as forward rudders.
– Higher Metabolism – A higher metabolism provided energy needed for the demands of flight. Pterosaurs likely had a covering of primitive feathers or fuzz that helped insulate their bodies.
These specialized adaptations enabled even the largest pterosaurs to take to the air.
Pterosaur Size
Pterosaurs ranged enormously in size, from sparrow-sized species to giant pterosaurs with 30 foot wingspans. Some key points about pterosaur sizes:
– The largest pterosaurs include Quetzalcoatlus and Hatzegopteryx, with wingspans over 30 feet. They were as tall as giraffes.
– Medium-sized pterosaurs had wingspans between 9-18 feet, similar to that of today’s largest flying birds.
– The smallest pterosaurs were the size of sparrows, with 5 inch wingspans. They could perch on branches and may have been able to flap their wings.
– Pterosaur size correlated with habitat. Smaller pterosaurs lived in forests, while larger ones lived in open coastal areas.
– Giant pterosaurs like Quetzalcoatlus weighed over 500 pounds but had hollow, lightweight bones and wing anatomy enabling 15-foot strides and flight.
– Larger pterosaurs may have been limited to gliding and soaring, while smaller ones could actively flap their wings.
Largest and Smallest Pterosaur Species
Largest Pterosaurs | Smallest Pterosaurs |
---|---|
Quetzalcoatlus – wingspan over 30 feet | Nemicolopterus – wingspan 5 inches |
Hatzegopteryx – wingspan over 30 feet | Mimodactylus – wingspan 6 inches |
Arambourgiania – wingspan 30 feet | Dendrorhynchoides – wingspan 16 inches |
When Did Pterosaurs Live?
Pterosaurs were the first vertebrates to achieve powered flight and lived alongside dinosaurs throughout the Mesozoic Era:
– They first appeared in the late Triassic Period, around 228 million years ago.
– Primitive pterosaurs existed from the Triassic through Jurassic Periods.
– They diversified into specialized forms by the Cretaceous Period and dominated skies while dinosaurs ruled the land.
– Pterosaurs went extinct at the end of the Cretaceous along with non-avian dinosaurs about 66 million years ago.
– They were the sole flying vertebrates for most of the Mesozoic until birds appeared and evolved flight about 150 million years ago.
Pterosaurs thus had a long reign of over 150 million years before birds took over as the dominant flying vertebrates after the dinosaurs went extinct.
Pterosaur Timeline
Era | Period | Years Ago | Pterosaur Milestones |
---|---|---|---|
Mesozoic | Late Triassic | 228-216 million | First pterosaur fossils appear |
Mesozoic | Jurassic | 201-145 million | Primitive long-tailed pterosaurs |
Mesozoic | Cretaceous | 145-66 million | Increasing diversity and size |
Mesozoic | Late Cretaceous | 66 million | Pterosaurs go extinct |
Pterosaur Diet
Different pterosaur species had diets specialized for their environments including fish, marine organisms, seeds, insects, small vertebrates, and even filter-feeding:
– Fish – Long-snouted pterosaurs like Rhamphorhynchus had spear-like beaks ideal for spearing fish.
– Insects – Smaller forest pterosaurs were insectivores, using their small peg-like teeth to eat insects.
– Seeds – Some pterosaurs may have been seed-eaters who could fly long distances dispersing seeds. Their slender jaws could pick and crush seeds.
– Marine Life – Pteranodontids had filter-feeding adaptations like wading birds for straining small marine animals from water.
– Meat – Large pterosaurs were likely scavengers who could swoop down and use their long jaws to grab small animal carcasses.
– Vertebrates – Some crested pterosaurs may have preyed on small reptiles, mammals, and dinosaurs.
Pterosaurs filled many aerial niches with their specialized diets adapted for catching and processing different types of food while airborne.
Pterosaur Extinction
Pterosaurs ruled ancient skies for over 150 million years but went extinct along with non-avian dinosaurs at the end of the Cretaceous Period about 66 million years ago. Several theories exist for their extinction:
– Asteroid impact – The Chicxulub asteroid impact caused climatic changes that led to ecosystem collapse and mass extinctions. Pterosaurs likely went extinct from global food chain disruptions.
– Volcanic eruptions – Major volcanic eruptions in India at the end of the Cretaceous also released climate-changing gases and ash that impacted environments.
– Competition – The later appearance of birds as flying competitors may have contributed to pterosaur extinctions.
– Reproduction – Some evidence indicates pterosaurs relied on fragile inland nesting habitats that may have been disrupted.
– Combination of factors – Most scientists conclude it was a combination of catastrophic geologic events and ecological competition that led to pterosaur extinction.
While their reign ended, pterosaurs were among the most successful flying animals ever known, dominating ancient skies for over 150 million years.
Discoveries and Study
Pterosaur research continues yielding new discoveries about their anatomy, diversity, behavior, and evolution:
– First discoveries – Pterosaur fossils were first recognized in the late 18th century but early finds were fragmentary and poorly understood.
– New species – Over 130 pterosaur genera have been identified and described, and new species continue to be found.
– Soft tissue impressions – Rare soft tissue impressions have revealed details about wing membranes and coverings like fur or pycnofibers.
– Behavioral clues – Trackways and evidence from eggs and nests have provided information about gait, posture, reproduction, and growth.
– Biomechanics – Improved biomechanical studies and aerodynamic modeling have shed light on exactly how they flew.
– Phylogeny – Phylogenetic analyses continue to better establish pterosaur relationships and evolution.
– Technology – CT scanning, stable isotopes, microscopy, and other technologies offer new ways to analyze pterosaur fossils.
– Future finds – Much remains to be learned and pterosaur research will continue as new discoveries emerge from existing and new fossil sites worldwide.
Pterosaurs were uniquely successful flying reptiles that left no modern descendants, so there is still much to uncover about their ancient reign.
Key Facts About Pterosaurs
- Lived 228-66 million years ago in the Triassic, Jurassic and Cretaceous periods
- Were reptiles, close cousins to dinosaurs but not dinosaurs themselves
- Evolved powered flight – first vertebrates to fly
- Had wings formed by skin membranes stretched between body and elongated fourth finger
- Ranged from sparrow sized to over 30 foot wingspans
- Lived on all continents in diverse environments
- Had specialized diets adapted for catching food in flight
- Went extinct along with non-avian dinosaurs 66 million years ago
- Hundreds of pterosaur species have been identified from fossils
- Research continues to uncover new insights into pterosaur anatomy, diversity, flight dynamics, and extinction
Conclusion
Pterosaurs were spectacularly successful flying reptiles that ruled ancient skies for over 150 million years. They were the first vertebrates to evolve powered flight and their adaptable bodies let them diversify into hundreds of aerial species worldwide. Pterosaurs exhibited great variation in size, anatomy, and feeding adaptations. While the pterosaur reign ended with the dinosaur extinctions 66 million years ago, discoveries continue to reveal new insights into these extraordinary ancient fliers. Pterosaurs remain one of evolution’s greatest innovations in developing the ability for vertebrates to take to the air.