Episode 164 – Sailfin Dragon Lizard: The Icarus Iguana

“…and today we’re talking about a modern day dinosaur with a name to match. But more on that later.”

Lizards sometimes retain primordial qualities. To look at them, you may see the scaly faces of ages long gone. The sailfin dragon lizard has a look that matches it’s fantastical name. But the dinosaur-esque nature of this reptile doesn’t mean it doesn’t have a few new tricks in it’s arsenal. This dragon makes its home in near the water, and he brings some interesting adaptations to the taxonomic table. Improving on the tried and reptile design might be the best option for this aqua-dragon in Life, Death, and Taxonomy. 


  • This is a dinosaur iguana
  • It has a long body, dry scaly armor-like wrinkle skin, and four short, squat legs with feet tipped with sharp claws
  • It has a row of small spikes lining its spine from the base of its neck to the tip of its tail
  • It’s head and face are distinctly gecko-like with a short snout, defined jaw, and angry eyes
  • Like many lizards, it has a throatal flap called a dewlap that hangs down from its neck and is used to woo potential mates.
  • Basically your typical iguana, which is a common sight for South Floridians
  • The thing that sets this guy apart is his tail. While most iguanas have a thin, whip-like tail, the male sailfin dragon has a thick tail with a large crest that spans the first fourth of the length of the tail. 
    • It has ridges segmenting the tail and the crest is partially translucent
    • Appropriately, it looks just like a fin or a large curved feather
    • Makes it look similar to the fierce Dimetrodon
  • The other oddity for this guy is that his scales are all kinds of crazy colors. 
    • South Florida iguanas get to be bright green or orange, but the hydrosaurus is often a mottled purple with bluish green. The older they get, the purpler they become.

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We don’t have a new measure up intro this week. 

  1. Donkey
  2. Mule
  3. Zebra
  4. Cayuse


  • 24 to 30 inches (76 cm)
  • How many sailfin lizards go into the length of Sauroposeidon proteles?
  • Hint: Sauroposeidon proteles is thought to be the tallest dinosaur that ever lived. It was first discovered when four vertebrae were found and thought to be petrified tree trunks because they were too large to be animal bones. 
  • 23.6 sailfin dragons. If these vertebrae belong to an anatomically traditional sauropod, the animal could be as tall as 17–18 m (56–59 ft).

Sailfin height

  • 2.7 inches (7 cm)
  • How many sailfin fins go into the largest sailfish ever fished?
  • Hint: Sailfish are incredibly fast open ocean fish. Because of their elusive speed, they are a favored prize among sport fishermen.
  • 49 sailfin sails. The largest sailfish ever caught was 11.2 feet (340 cm).

Fast Facts

  • Range: Only lives in the Philippines. It likes tropical areas with bodies of water nearby like rivers and mangrove estuaries.
  • Diet: fruit, leaves, flowers, insects, and smaller animals

Major Fact

Sailfin dragon lizards are semi-aquatic, which means they enjoy the land and water. They like to live around rivers and streams. Like other large semi-aquatic reptiles, they’re herbivores and spend their days eating vegetation and basking in the sub. 

However, their primary defense is to take to the water when predators approach. And their bodies are specially adapted to life in the water. 

They’re able to remain underwater for long periods of time. To escape predators, they can jump in the water, sink to the bottom, and stay there for up to an hour before needing to come back up. 

Males also have a large sailfin that starts at the base of their tail and arches to the center of their tail. This sail could be used for several purposes. They may help with swimming and they could also help cool and warm them up quickly as blood flows close to the surface of the skin through the sail, like an elephant ear.

However, female sails are much smaller, so the primary purpose of big sails might be for something else. Males use large impressive sails as a territorial display. Incidentally, these intimidating tail sails is what the AWOLNATION song is actually about.

Despite these dinosaur-esque tail ornaments, the sailfin dragon’s most impressive aquatic anatomy adaptation is their feet. 

Their toes are flat like they’re cartoon carpenters with bad aim. Adults use this flatfootedness to swim more efficiently in the water. Their feet act like flippers with a wider surface area allowing them to push off the water. 

But adolescents have a different way of doing things as kids are want to do. Younger, smaller sailfins can actually use these flat feet to run on water. Their flat toes slap against the surface tension of the water and push off to the next step, like snow shoes. This allows the more vulnerable juveniles to escape predators quickly across the surface of rivers and ponds before diving below or reaching the other side.