Eryx miliaris
Eryx miliaris, known as the dwarf sand boa, desert sand boa, and if formally synonymised with Eryx tataricus, as Tartar sand boa, is a widely distributed, largely Asian species of snake of the Boidae family. On behalf of the International Union for Conservation of Nature, scientists assessed the populations of E. miliaris/''tataricus'' across its range of habitats for the IUCN Red List of Threatened Species in April 2016, assigning them the status of "Least Concern".
The IUCN, the Reptile Database, and other contributing sources paint a relatively consistent picture of the distribution of these and other synonymous species, ranging from Iraq and Iran in the east, along the western shore of the Caspian Sea through all of central Asia, south into Afghanistan and Pakistan, and north and west into southern Russia, Mongolia, and Inner Mongolia in northern China.
The species may be the inspiration for a cryptid of legend, the Mongolian death worm.
Description
Phylogeny, naming, synonymy
Eryx miliaris is commonly known as the dwarf sand boa and desert sand boa, and is a species of snake in the Boidae family. Formal subspecies—sometimes termed direct children—include E. miliaris miliaris and E. miliaris nogaiorum . Common names that E. miliaris is reportedly known by are the mountain sand boa, and various geographical names including Russian and Turkmen sand boas. As well, the various subspecies have sometimes been given distinct common names, e.f., E. miliaris nogaiorum as the black sand boa.General physical description
The appearance of E. miliaris is described by WCH-University of Adelaide as usually having an adult length of 30 centimeters, extending to a maximum of approximately 90 centimeters.Other sources highlight that, as with most other sand boas, females are larger than males, and that E. tataricus are the larger variants ; these sources note that adult Tartar sand boa males rarely reach 75 centimeters in length, while adult females can reach 120 centimeters.
E. miliaris, per se, is reliably described as being, relative to other snakes:
Small in length, cylindrical... stout bodied snake with a very short blunt tail... ead is indistinct from neck. nout is rounded when viewed from above and pointed and projecting when viewed from the side. yes are small in size, located dorsally with vertically elliptical pupils. orsal scales are smooth to weakly keeled.
Its body has also been described as strong and round, and its tail as thick. With regard to the coloration of its scales, E. miliaris is presented as a mixture of brown, red and black, which turns white on both sides.
Behaviour
Activity, diet
The WCH-University of Adelaide describe E. miliaris as "errestrial and mainly diurnal... with nocturnal tendencies in hottest months". The IUCN description of the species, which specifically refers to E. miliaris, presents it as "nocturnal during the hot part of the year", indicates that it is "common on the surface in spring", and states that it is active from "March to October over most of its range".With regard to its diet and prey, the WCH-University of Adelaide describes E. miliaris as feeding "mainly on rodents and lizards". Elsewhere its prey have been described as including small birds, desert lizards, and other small animals.
Reproductive">Reptile#Reproduction">Reproductive ([viviparity])
E. miliaris is described as being viviparous in an IUCN description, and as ovoviparous by Peter Uetz and Jakob Hallermann at the Reptile Database. D.G. Blackburn of Trinity College has noted that this term has been used discrepantly in the herpetology literature, arguing that use of the term be avoided "in favour of unambiguous alternatives that explicitly distinguish patterns defined on the basis of reproductive products at deposition from patterns based on sources of nutrients for embryonic development" .In the case of genus Eryx, and restricting use of terminology to the simple oviparous reproduction for egg-laying cases and viviparous reproduction for live-bearing cases, Eryx is described as a genus as being viviparous, with the exception of species Eryx jayakari ; this analysis and generalisation places the titular subject, Eryx miliaris in the category of viviparous.
The IUCN—again limiting its description just to the dwarf/desert sand boa —describes the viviparity of the species as having females giving birth in July-August, in numbers in the range of 4 to 15 young. The Tartar sand boa has also been described as viviparous, with the female giving birth to 7-10 young.
Other behaviours
E. miliaris has been compared to the Indian sand boa for its behaviour of rounding its body when threatened.Habitat, distribution, threat status
In the geographic regions Eryx miliaris occupies, the WCH-University of Adelaide describes it being found at "levations up to about 2700 metThe RDB describes the geographic range of E. miliaris, per se, as being:
- throughout Iraq;
- throughout Kazakhstan, Uzbekistan, Turkmenistan, and Afghanistan;
- in southern Russia, from the Caspian Sea to its border with Kazakhstan;
- in China, from Xinjiang, through Gansu and Ningxia to Inner Mongolia; and in
- Mongolia itself.
The IUCN description of E. miliaris
The RDB then presents the range of the synonymous E. tataricus, as overlapping with that described for E. miliaris, specifically,
- from Iran, through western Pakistan into Afghanistan, Tajikistan, and Kyrgyzstan;
- into eastern Kazakhstan, and Uzbekistan, and eastern Turkmenistan;
- into the areas in China identical to E. miliaris ; and in
- southern Mongolia.
Finally, the RDB presents E. speciosus, a species it describes as synonymous with E. tataricus, as having a range overlapping with E. tataricus—in Pakistan and Tajikistan. The IUCN, on the other hand, presents E. speciosus as a subspecies of E. tataricus, and states a range limited to Tajikistan.
Somewhat conflictingly overall, distribution information is summarised by the Integrated Taxonomic Information System, which assigns E. miliaris to the geographic divisions of Southern Asia, Europe, and Northern Asia.