Circulus (zoology) - AbsoluteAstronomy.com

A circulus is a rarely occurring reptilian

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

social group

Group (sociology)

In the social sciences a social group can be defined as two or more humans who interact with one another, share similar characteristics and collectively have a sense of unity...

where there is interaction and personal exchange between individuals. Members will often protect and defend young - even if not of direct genetic linkage

Genetic linkage

Genetic linkage is the tendency of certain loci or alleles to be inherited together. Genetic loci that are physically close to one another on the same chromosome tend to stay together during meiosis, and are thus genetically linked.-Background:...

. "Circulus" is a Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

based term; one definition of the word is "a social gathering or circle company".Andrews,E.A; 1875. Latin-English Lexicon. Harper & Brothers publishers, 329 & 331 Pearl Street, Franklin Square, New York, U.S.A. 1663 pp.
Most reptiles are indifferent socially to each other as adults or to offspring.

Behaviours

Among crocodilians and certain lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s, there is a much greater interaction between members. Young will be guarded and defended for a considerable period of time. Crocodilians of both sexes carry and assist young hatchling

Hatchling

In oviparous biology, a hatchling is the newborn of animals that develop and emerge from within hard-shell eggs. The offspring of birds are often hatched naked and with their eyes closed. The hatchling relies totally on its parents for feeding and warmth. Hatchlings precede nestlings in the chick's...

s to the water and guard them. The gharial

Gharial

The gharial , , also called Indian gavial or gavial, is the only surviving member of the once well-represented family Gavialidae, a long-established group of crocodilians with long, slender snouts...

(Gavialis gangeticus) has to nudge young to the water because their teeth are too sharp to carry them. Sub-adult members of a crocodilian social group will often stand by a female laying eggs or retrieving young from a nest to keep predators away. The female Asian forest tortoise

Manouria emys

Asian forest tortoise , also known as Asian brown tortoise, is a species of tortoise found in India , Bangladesh, Burma , Thailand, Malaysia and Indonesia .-Description:...

(Manouria emys) has been reported to guard a nest site for a short period after egg laying but this instinct is very short lived.

In stump-tailed skink

Stump-tailed skink

Tiliqua rugosa is a short-tailed, slow moving species of blue-tongued skink found in Australia. Three of the four recognized subspecies are found only in Western Australia, where they are known collectively by the common name bobtail. The name shingleback is also used, especially for T. rugosa...

s (Trachydosaurus spp) and Solomon Islands skink

Solomon Islands skink

The Solomon Islands skink is an arboreal species of skink endemic to the Solomon Islands. It is the largest known extant species of skink...

s (Corucia spp), long term bonding of pairs with each other and other members has been recorded. In the case of Corucia, orphan

Orphan

An orphan is a child permanently bereaved of or abandoned by his or her parents. In common usage, only a child who has lost both parents is called an orphan...

ed young have been observed being adopted into the Circulus.

The social bond and parental attention of reptiles appears equal in circulus containing egg

Egg (biology)

An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

-laying reptiles compared to those with live bearing

Ovoviviparity

Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...

reptiles. Another case of egg-laying lizards with a circulus is the Crocodile skink (Tribolonotus gracilis
Tribolonotus gracilis
Tribolonotus gracilis is a species of skink found in New Guinea. They live in tropical forests and have also been found in human-populated areas. They are commonly known as Red-Eyed Crocodile Skinks, or, rarely, Red-Eyed Bush Crocodile Skinks.Tribolonotus gracilis is one of the few species of...

). The female will sit on the egg and guard the young. As in the case of Corucia, the young tend to stay close to the parents, especially, the mother who guards the neonate. The young skink will often climb on the abaxial

Anatomical terms of location

Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

area of the female or male for protection and security, just as in the case of the Solomon Islands skink (Corucia zebrata).

Behaviours

Further reading