The sheltopusik (''Pseudopus apodus''), also commonly called Pallas's glass lizard, the European legless lizard, or the European glass lizard, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of large glass lizard found from

Southern Europe Southern Europe is also known as Mediterranean Europe, as its geography is marked by the Mediterranean Sea. Definitions of southern Europe include some or all of these countries and regions: Albania, Andorra, Bosnia and Herzegovina, Bulgaria, C ...

Central Asia Central Asia is a region of Asia consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The countries as a group are also colloquially referred to as the "-stans" as all have names ending with the Persian language, Pers ...

Taxonomy

The sheltopusik was previously included in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Ophisaurus ''Ophisaurus'' (from the Greek 'snake-lizard') is a genus of superficially snake-like legless lizards in the subfamily Anguinae. Known as joint snakes, glass snakes, or glass lizards, they are so-named because their tails are easily broken; li ...

'', but has since been placed in its own genus ''Pseudopus''. It was originally described in 1775 by

Peter Simon Pallas Peter Simon Pallas Fellow of the Royal Society, FRS FRSE (22 September 1741 – 8 September 1811) was a Prussia, Prussian zoologist, botanist, Ethnography, ethnographer, Exploration, explorer, Geography, geographer, Geology, geologist, Natura ...

as ''Lacerta apoda''. There are three subspecies: * ''P. a. apodus'' (Pallas, 1775) – the type subspecies, ranging from

Crimea Crimea ( ) is a peninsula in Eastern Europe, on the northern coast of the Black Sea, almost entirely surrounded by the Black Sea and the smaller Sea of Azov. The Isthmus of Perekop connects the peninsula to Kherson Oblast in mainland Ukrain ...

through

Transcaucasia The South Caucasus, also known as Transcaucasia or the Transcaucasus, is a geographical region on the border of Eastern Europe and West Asia, straddling the southern Caucasus Mountains. The South Caucasus roughly corresponds to modern Armenia, ...

, east to

as far as

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

* ''P. a. levantinus'' Jablonski, Ribeiro-Junior, Meiri, Maza, Mikulíček & Janzik, 2021 – restricted to the

Levant The Levant ( ) is the subregion that borders the Eastern Mediterranean, Eastern Mediterranean sea to the west, and forms the core of West Asia and the political term, Middle East, ''Middle East''. In its narrowest sense, which is in use toda ...

, from southern

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

south to

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

and

Palestine Palestine, officially the State of Palestine, is a country in West Asia. Recognized by International recognition of Palestine, 147 of the UN's 193 member states, it encompasses the Israeli-occupied West Bank, including East Jerusalem, and th ...

* ''P. a. thracicus'' (Obst, 1978) – the westernmost subspecies, ranging from

Croatia Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

, east to western Turkey Despite only being described in 2021, ''P. a. levantinus'' is the largest and most genetically diverse of the subspecies, indicating an older and more complex evolutionary history compared to its sister subspecies.

Etymology

comes from

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

, literally meaning "fake-legged" or without legs. The common name "sheltopusik" comes from

Russian Russian(s) may refer to: *Russians (), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *A citizen of Russia *Russian language, the most widely spoken of the Slavic languages *''The Russians'', a b ...

(), which translates most directly as "yellow-bellied".

Skull anatomy

The skull is elongated, twice as long as it is wide and widest at the posteroventral portions of the jugals, where the cheeks proceed to narrow into the snout. The exonarial fenestra (external naris) is similarly elongated and elliptical. The orbits, which lie in a posterior portion of the anterior part of the skull, are large. The premaxillary–maxilla has an elongated opening and has rounded ends. It is positioned between the forked premaxillary process of the maxilla and the maxillary and vomeromaxillary processes of the premaxilla.

Description

The sheltopusik can reach a length of . It is tan colored, paler on the ventral surface and the head, with a ring-like/segmented appearance that makes it look like a large

earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...

with a distinctive fold of skin down each side called a lateral groove. Small (2-mm) rear legs are sometimes visible near the

cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...

. Though the legs are barely discernible, the sheltopusik can be quickly distinguished from a

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

by its

ear In vertebrates, an ear is the organ that enables hearing and (in mammals) body balance using the vestibular system. In humans, the ear is described as having three parts: the outer ear, the middle ear and the inner ear. The outer ear co ...

s, eyelids, and

ventral scales In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...

. This species exhibit sexual dimorphism as males are on average larger than females.

Habitat and behaviour

''P. apodus'' inhabits open country, such as short grassland or sparsely wooded hills. It consumes

arthropods Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

and small

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

Snails A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

and

slugs Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a sma ...

appear to be its favorite prey, which may explain why it is particularly active in wet weather, although it prefers a dry habitat. Breaking through the shells of snails is an especially easy task due to their teeth and jaw structure.

Defensive behaviour

Due to its size, the sheltopusik tends to respond to harassment by hissing, biting, and musking. It is less likely to drop off its tail than some other species that display caudal

autotomy Autotomy (from the Greek ''auto-'', "self-" and ''tome'', "severing", αὐτοτομία) or 'self-amputation', is the behaviour whereby an animal sheds or discards an appendage, usually as a self-defense mechanism to elude a predator's grasp ...

. However, these occasional displays of caudal autotomy are responsible for the name " glass lizard" (or "glass snake"). The released tail may break into pieces, leading to the myth that the lizard can shatter like glass and reassemble itself later. In reality, if the tail is lost, it grows back slowly, but is shorter and darker. The replacement tail may grow back to full length after an extended period of time.

Reproduction

About 10 weeks after mating, the female ''P. apodus'' lays about eight eggs, which she hides under bark or a stone, and often guards them. The young hatch after 45 to 55 days. They are typically about long and usually start to eat after four days.

In captivity

Sheltopusiks are frequently available in the exotic pet trade, though rarely captive-bred. They do not typically tolerate a large amount of handling, but they adapt to captivity well, feeding on

crickets Crickets are orthopteran insects which are related to bush crickets and more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 886 ...

, meal worms, small

mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

, eggs, snails, or pieces of meat. They are even known to accept these meals from a keeper's

tweezers Tweezers are small hand tools used for grasping objects too small to be easily handled with the human fingers. Tweezers are thumb-driven forceps most likely derived from tongs used to grab or hold hot objects since the dawn of recorded history. ...

, or even from their hands once they become used to captivity. However, sheltopusiks do get excited around food and have surprisingly powerful jaws. They make hardy captives, capable of living up to 50 years.

Relationship with humans

Remains of the Levant subspecies (''P. a. levantinus'') are known from

Natufian The Natufian culture ( ) is an archaeological culture of the late Epipalaeolithic Near East in West Asia from 15–11,500 Before Present. The culture was unusual in that it supported a sedentism, sedentary or semi-sedentary population even befor ...

sites in

, suggesting that it was eaten by the local population at the time.

Gallery

File:Pseudopus apodus, Uzbekistan, Surxondaryo Region, Kugitang Mountain Range imported from iNaturalist photo 224163004.jpg, In Uzbekistan File:Pseudopus apodus, West Greece, Peloponnese, Western Greece and the Ionian Islands, GR imported from iNaturalist photo 282395812.jpg, In Greece File:Pseudopus apodus, Meghri, Syunik Province, Armenia imported from iNaturalist photo 263273448.jpg, In Armenia File:Pseudopus apodus, Primorsko, Bulgaria imported from iNaturalist photo 213646243.jpg, In Bulgaria File:Circaetus gallicus with Pseudopus apodus, Εθνικό Δρυμό Πάρνηθας, Κρυονερίου, Восточная Аттика, GR imported from iNaturalist photo 207074472.jpg, Caught by a short-toed snake eagle File:Pseudopus apodus crawling.webm, Moving on a brick road

References

External links

* * * * * {{Taxonbar, from=Q41669 Anguids Legless lizards Reptiles of Central Asia Lizards of Asia Lizards of Europe Reptiles described in 1775 Taxa named by Peter Simon Pallas Articles containing video clips