Henophidia
The giant snake -like ( Henophidia ) are a group sometimes very large expectant snakes that are found on all tropical continents.
Features
The giant snake -like include the largest and longest snakes, including the reticulated python (Python reticulatus ) with a maximum length of about 7 meters and the Great Anaconda ( Eunectes murinus ), which can be up to 9 feet long. Most morphologically conservative, there are also some derivative, underground living forms, usually only achieved by a length of one meter or less. The giant snake -like the after spurs are often visible next to the cloaca as rudiments of hind limbs, this group still are often remnants of the pelvic girdle available. Between prefrontal and parietal bone, the foramen opticum and is located on the lower jaw of Meckel's canal. The premaxilla of the giant snake -like is dentate.
System
Contrary to earlier assumptions, the giant snake -like are probably not a monophyletic group, but only an artificial Summary primitive snake families.
The families pythons ( Pythonidae ), boa snakes ( Boinae ) and Boas ( Erycinae ) were due to physical characteristics as subfamilies together in the family of giant snakes (formerly Boidae ) grouped. Along with the listed in the following families and subfamilies have shaped the superfamily of snake -like ( Henophidia ), one of three superfamilies within the snakes ( Serpentes ). They were as evolved considered as consisting of the three families American Blind Snakes ( Anomalepidae ) Blind Snakes ( Typhlopidae ) and Slender Blind Snakes ( Leptotyphlopidae ) existing superfamily of blindsnakes ( Scolecophidia or Typhlopoidea ) but more rudimentary than the vipers and viper -like ( Colubroidea or Xenophidia ).
Earlier classification of the giant snake -like on the basis of physical characteristics:
- About family: Scavenge and Giant Snake-like ( or Boidea Henophidia ) Family: Roll snakes ( Aniliidae / Ilysiidae )
- Family: Wühlschlangen ( Anomochilidae )
- Family: boas ( Boidae ) Subfamily: boa snakes ( Boinae )
- Subfamily: Sand Boas ( Erycinae )
- Subfamily: python ( Pythoninae )
- Subfamily: Tropidophiinae
- Subfamily: Ungaliophiinae
- Subfamily: Xenophidioninae
- Subfamily: True shield tails ( Uropeltinae )
- Subfamily: pipesnakes ( Cylindrophiinae )
Recent genetic studies refute this close relationship, however. Finally, the classification of snakes is not yet clear, however, agree some investigation concur in representing that the closest relatives of pythons ( Pythonidae ) the family of red-tailed pythons ( Loxocemidae ) and the family of Erdschlangen ( Xenopeltidae ). Together they form thus the superfamily Pythonoidae. The two families Loxocemidae and Xenopeltidae were previously a basal to the giant snakes group within the giant snake -like, for example, Lee et al. Had described 14 morphological differences. Which of these differences for the new array are still valid, studies have yet to show. The closest relatives of Boinae are in addition to the sand boas boas.
The following is a list of the families who were formerly placed in the giant snake -like, according to the scheme of the Reptile Database, which tries to illustrate the current state of the classification of snakes:
- Superfamily Uropeltoidea S. L. Family Wühlschlangen ( Anomochilidae )
- Family pipesnakes ( Cylindrophiidae )
- Family Shield tails ( Uropeltidae )
- Family Spitzkopf pythons ( Loxocemidae )
- Family pythons ( Pythonidae )
- Family Erdschlangen ( Xenopeltidae )
- Family Boas ( Boidae ) Subfamily boa snakes ( Boinae )
- Subfamily boas ( Ungaliophiinae )
- Subfamily sand boas ( Erycinae )
- Family Roll snakes ( Aniliidae )
- Family Bolyerschlangen ( Bolyeriidae )
- Family Erdboas ( Tropidophiidae )
The former a superfamily of snake -like was therefore split into three new superfamilies whose internal structure has changed as well. The position of the roll snakes, Bolyerschlangen and Erdboas is not yet determinable with sufficient certainty.