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Tetrapodophis (Greek meaning "four-footed snake") is an extinct genus of lizard from the Early Cretaceous aged Crato Formation of Brazil. It has an elongated snake-like body, with four disproportionately short limbs.
Pachyrhachis is among the oldest known snakes and retains well-developed hind limbs, suggesting it represented a transitional form linking snakes to marine lizards (Lee and Scanlon 2002), though other studies place Pachyrhachis within the modern snake radiation as stem-Macrostomata (Zaher, 1998; Zaher & Rieppel, 1999).
The presence of the hind limbs presents a problem with this placement however. There are two major ideas for the presence of hind limbs in Pachyophiidae. The first is the secondary regaining of the limbs from legless ancestors, while the second is the possibility of multiple episodes of leg loss in snakes.
Similarly, there are snakes with tiny limbs that they hardly ever use. “If you don’t use something, in evolution, you lose it,” Beane said. Diet of glass lizards.
Large, well-developed limbs increase drag on swimming animals, so the limbs of Eupodophis and other early snakes may have become vestigial to save energy and make movement more efficient. No vestigial limbs whatsoever are present in the modern species, which lack transitional species remnants. What few species have them protrude as tiny spurs.
The fossil record of snakes is not expansive. [5] Nonetheless, multiple fossilized specimens document the progression of the development of leglessness within the suborder Serpentes. The species of extinct snake Najash rionegrina was first described in 2006, and has been proposed as the earliest branching taxa of the suborder Serpentes. [6]
2. Corn Snakes. Size: 2-4 feet on average, potentially up to 6 feet Lifespan: 15-20 years Corn snakes are fearsome hunters of rats and mice in the wild, but are fairly docile and tolerant of ...
Both families share a number of primitive characteristics. Nearly all have a relatively rigid lower jaw with a coronoid element, as well as a vestigial pelvic girdle with hind limbs that are partially visible as a pair of spurs, one on either side of the vent. In males, these anal spurs are larger and more conspicuous than in females. A long ...