Sand boas

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Sand boas
Arabian sand boa (Eryx jayakari)

Arabian sand boa ( Eryx jayakari )

Systematics
without rank: Toxicofera
Subordination : Snakes (serpentes)
Superfamily : Boa-like (Booidea)
Family : Boas (Boidae)
Subfamily : Sand boas
Genre : Sand boas
Scientific name of the  subfamily
Erycinae
Bonaparte , 1831
Scientific name of the  genus
Eryx
Daudin , 1802

The sand boas ( Eryx ) are a genus of snakes from the boas family . The genus includes twelve species, which are mainly found in Africa, the Middle East and Asia to India. The western sand boa is the only giant snake that can also be found in larger areas of Europe, the area of ​​the eastern sand boa only touches Europe on the northern edge of the Caspian Sea .

The generic name Eryx was chosen after the mythological figure Eryx , son of Aphrodite. Eryx was strangled by Heracles while wrestling. He was the eponymous regent of the city of Eryx on the mountain of the same name in Sicily, now called Erice in Italian .

features

The sand boas are small to medium-sized snakes that reach body lengths of 40 cm to about 100 cm. The smallest species is the Afghan sand boa ( Eryx elegans ), the longest the Indian sand boa ( Eryx johnii ). The habitus of the snakes is largely stocky with a short tail, the head is not separated from the body.

Characteristic is a very large snout shield, which extends far to the top of the head and has formed from the widened parietal shield (Scutum parietale). The top of the head is covered with many small, smooth scales. The eyes are small with an elliptical pupil and, depending on the species, can be on the top of the head or on the sides. The front teeth of the upper and lower jaw are also elongated. The skin structure has a sandfish effect .

Way of life

Sand boas occur in arid and semi-arid areas. They are mainly ambulance hunters who can burrow in the sand and wait for prey with only their eyes and nostrils peeking out. The prey is strangled by the sand boa embracing it or pressing it against hard objects. Chicks and similar non-defensive prey are also devoured alive. However, the sand boas mainly hunt mammals, sometimes lizards and only rarely birds.

With two exceptions, sand boas are ovoviviparous . Litter sizes of 4 to 17 young animals have been observed in captivity, which are 120–290 mm long, depending on the species. The Arabian sand boa ( Eryx jayakari ) from the Arabian Peninsula and the Sahara sand boa ( Eryx muelleri ) from North Africa lay eggs in the sand. The two species also appear to be closely related phylogenetically .

Some sand boas have strong venom in their saliva, but only in very small amounts.

Systematics

The genus Eryx was established in 1802 by the French zoologist François-Marie Daudin , the subfamily Erycinae in 1831 by the Italian biologist Charles Lucien Bonaparte . Because of the external similarity and a similar way of life, the West African earth python ( Calabaria reinhardtii ), the North American species Gummiboa ( Charina bottae ) and rose boa ( Lichanura trivirgata ) were later placed in the subfamily Erycinae . Today, however, according to molecular genetic analyzes, these species are assigned to the subfamilies Calabariinae (earth python) and Charininae (rubber boa and rose boa) within the boas family.

Within the genus Eryx , 13 types are distinguished:

Indian sand boa cub ( Eryx johnii )

Eryx colubrinus , eryx conicus , eryx muelleri , eryx somalicus and eryx whitakeri are used by some authors because of the formation of a wing leg -Mittelkammes, the merging with them narrow and in the row of teeth and the other eryx separated TYPES wide and of the row of teeth, classified in its own genus Gongylophis . However, this genre is not generally accepted.

The Afghan sand boa ( E. elegans ) is very similar to the western sand boa ( E. jaculus ), and the large sand boa ( E. tataricus ) can hardly be distinguished from the eastern sand boa ( E. miliaris ). It was therefore proposed to combine the similar species under the names Eryx jaculus and Eryx miliaris . Molecular genetic studies to date do not speak against it, so only the western and eastern sand boa would remain. In contrast, the subspecies E. tataricus vittatus is now widely regarded as a separate species, Eryx vittatus . The Eastern Sand Boa could therefore be a species complex whose composition is difficult to break down.

Individual evidence

  1. ↑ a b c d e B. Lanza, A. Nistri: Somali Boidae (genus Eryx Daudin 1803) and Pythonidae (genus Python Daudin 1803) (Reptilia Serpentes) . In: Tropical Zoology . tape 18 , 2005, p. 67-136 .
  2. ^ A b R. Graham Reynolds, Matthew L. Niemiller, Liam J. Revell: Toward a Tree-of-Life for the boas and pythons: Multilocus species-level phylogeny with unprecedented taxon sampling. Molecular Phylogenetics and Evolution, 71, pp. 201-213, 2014
  3. ↑ Daudin 1802. Histoire Naturelle, Générale et Particulière des Reptiles. vol. 7. Paris: Dufart [1802], 436 pp.
  4. ↑ Robert Alexander Pyron, Frank T. Burbrink, John J Wiens: A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 2013, 13: 93 doi: 10.1186 / 1471-2148-13-93
  5. ↑ a b Eryx in The Reptile Database
  6. ↑ Naeimeh Eskandarzadeh, Nasrullah Rastegar-Pouyani, Eskandar Rastegar-Pouyani, Jamil Zargan, Ashkan Hajinourmohamadi, Roman A. Nazarov, Soheil Sami, Mahdi Rajabizadeh, Hossein Nabizadeh and Majid Navaian. 2020. A New Species of Eryx (Serpentes: Erycidae) from Iran. Zootaxa . 4767 (1); 182-192. DOI: 10.11646 / zootaxa.4767.1.8
  7. ↑ Eskandar Rastegar-Pouyani & Naeimeh Eskandarzadeh: Re-evaluation of the taxonomic status of sand boas of the genus Eryx (Daudin, 1803) (Serpentes: Boidae) in north-eastern Iran using sequences of the mitochondrial genome. Zoology in the Middle East, 10, pp. 60-64, 2014
  8. ^ Robert Alexander Pyron, R. Graham Reynolds, Frank T. Burbrink: A Taxonomic Revision of Boas (Serpentes: Boidae) . Zootaxa, 3846, 2, pp. 249-260, 2014 doi : 10.11646 / zootaxa.3846.2.5

literature

  • Eryx Daudin, 1803 - Sand Boas . In: Wolfgang Böhme (Ed.): Handbook of Reptiles and Amphibians in Europe; Volume 3 / I, Schlangen (Serpentes) I. Aula-Verlag, Wiebelsheim 1993, ISBN 3-89104-003-2 , pp. 32-33.

Web links

Commons : Sandboas ( Eryx )  - Collection of images, videos and audio files