Ctenosaura similis

Ctenosaura similis, commonly known as the black iguana or black spiny-tailed iguana, is a lizard native to Mexico and Central America. It has been reported in some Colombian islands in the Caribbean Sea and Pacific Ocean, and has been introduced to the United States in the state of Florida. It is the largest species in the genus Ctenosaura. They are typically found in areas such as grasslands and forests. The black spiny-tailed iguana was first described by British zoologist John Edward Gray in 1831. The generic name, Ctenosaura, is derived from two Greek words: ctenos (Κτενός), meaning "comb" (referring to the comblike spines on the lizard's back and tail), and saura (σαύρα), meaning "lizard". Its specific name is the Latin word similis meaning "similar to", a common description found in Linnean taxonomy when referring to a new taxon. Black spiny-tailed iguana have distinctive black, keeled scales on their long tails, which gives them their common name. They, along with C. pectinata, are the largest members of the genus Ctenosaura. The males are capable of growing up to in length and the females are slightly shorter, at . They have a crest of long spines which extends down the center of the back. Although coloration varies extremely among individuals of the same population, adults usually have a whitish gray or tan ground color with a series of 4–12 well-defined dark dorsal bands that extend nearly to the ventral scales. Males also develop an orange color around the head and throat during breeding season with highlights of blue and peach on their jowls. Black spiny-tailed iguanas are excellent climbers, and prefer a rocky habitat with plenty of crevices to hide in, rocks to bask on, and nearby trees to climb. They are diurnal and fast moving, employing their speed to escape predators but will lash with their tails and bite if cornered. The Guinness Book of World Records lists this as the world's fastest lizard, with a maximal sprint speed of .