The Earless monitor lizard (Lanthanotus borneensis) is a semi-aquatic, brown lizard native to northern Borneo

Borneo

Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

. It is the only species in the family Lanthanotidae, a group related to the true monitor lizard

Monitor lizard

Monitor lizards are usually large reptiles, although some can be as small as in length. They have long necks, powerful tails and claws, and well-developed limbs. Most species are terrestrial, but arboreal and semiaquatic monitors are also known...

s, as well as to the beaded lizard

Heloderma

Heloderma, the only genus of the family Helodermatidae, consists of venomous lizards native to the southwestern United States, Mexico and as far south as Guatemala. It includes two separate species, with six subspecies...

s.

Earless monitor lizards are around 20 centimetres in length, and have reduced eyes and limbs, a thick body, and strongly keeled scales

Scale (zoology)

In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...

. Despite the name, it is capable of hearing, although it lacks a tympanum

Eardrum

The eardrum, or tympanic membrane, is a thin membrane that separates the external ear from the middle ear in humans and other tetrapods. Its function is to transmit sound from the air to the ossicles inside the middle ear. The malleus bone bridges the gap between the eardrum and the other ossicles...

 or other visible signs of ears. It is a burrowing, nocturnal animal, feeding on earthworm

Earthworm

Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...

s and similar prey. In captivity

Captivity (animal)

Animals that live under human care are in captivity. Captivity can be used as a generalizing term to describe the keeping of either domesticated animals or wild animals. This may include for example farms, private homes and zoos...

, it has been known to eat squid

Squid

Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

, pieces of fish and liver. Like its closest relatives, it is oviparous, although little else is known about its reproduction.

This species is very rare, and most known specimens are preserved, though these, also, are rare. The species is primarily of interest to scientists, since it is an evolutionary outgroup for both varanid and helodermatid lizards.

External links

• Dr. Jessie Maisano, 2001, "Lanthanotus borneensis" (On-line), Digital Morphology. Accessed June 20, 2010 at http://digimorph.org/specimens/Lanthanotus_borneensis/.
• Family lanthanotidae in the J. Craig Venter Institute Reptile Database