|My sole criticism of this film: |
not enough snakes
a parthenogenetic blindsnake
|Phylogenetic tree showing currently accepted hypotheses of snake relationships. Figure from Lee et al 2007. |
Thick lines are supported by both morphological and molecular studies, thin solid lines are supported
primarily by similarity of morphology, dotted lines are supported primarily by molecular analyses.
|Calabaria reinhardtii, |
the Cameroon Burrowing Boa,
the only oviparous booid
|Figure from Pyron et al. 2011|
- Legless lizards: There are several groups of legless lizards. The North American glass lizards are among the most familiar. All have external ear openings and most have eyelids. In one sense, snakes are but one very diverse group of legless lizards.
- Amphisbaenians: These are also technically lizards, but under some older taxonomies they are referred to as a separate group of reptiles, because they have a vestigial right lung and have a unique skeletal structure.
- Caecilians: These most primitive of amphibians have slimy skin and are found underground in the world's tropics. Many are common prey of coral snakes.
- Eels: Elongate fishes that actually do have limbs in the form of fins. There are several groups of fishes that are all colloquially called eels, including spiny eels, fire eels, electric eels, and true eels (Anguilliformes). Some amphibians are also sometimes called eels, including amphiumas or conger eels, sirens or mud eels, and rubber eels, a kind of caecilian.
- Worms: There are several different major groups of worms, including roundworms (nematodes), flatworms (platyhelminths), and segmented worms (annelids).
2 A monophyletic group is one that contains a common ancestor and all of its descendants. Examples include groups like animals, vertebrates, mammals, birds, amphibians, primates, and snakes. A non-monophyletic group is one that either omits some descendants (e.g., "reptiles", which does not include birds, or "fishes", which does not include tetrapods) or omits the common ancestor (e.g., warm-blooded vertebrates, which includes mammals and birds but not their cold-blooded common ancestor).↩