TheMexican mole lizard (Bipes biporus), alsocommonly known as thefive-toed worm lizard, or simply asBipes, is aspecies ofamphisbaenian in thefamilyBipedidae.[1] The species isendemic to theBaja California Peninsula. It is one of threespecies ofamphisbaenians that have legs.
| Mexican mole lizard | |
|---|---|
 | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Clade: | Amphisbaenia |
| Family: | Bipedidae |
| Genus: | Bipes |
| Species: | B. biporus |
| Binomial name | |
| Bipes biporus (Cope, 1894) | |
| Synonyms[3] | |
Studies demonstrate that Mexican mole lizards have very low genetic variation among the threeallopatric species found in this genus. All three allopatric species have seven fixed identical loci and only six different fixed loci. This is due to the similar environments that all three species are found in.
B. biporus is pink and worm-like, 18–24 cm (7.1–9.4 in) in snout-to-vent length (SVL) and 6–7 mm (0.24–0.28 in) in width. It lives for one to two years. Its skin is closely segmented to give a corrugated appearance, and like earthworms, its underground movement is byperistalsis of the segments. Its blunt head allows it to burrow into sandy soils efficiently. The forelegs are short, strong and paddle-like, while the hind legs have disappeared, leaving behind onlyvestigial bones visible inX-rays.[1] The tail isautotomous without anyregeneration. Due to sacrificing the development of its ear to permit it to dig more efficiently, the Mexican mole lizard has evolved to have its skin transmit vibrations to thecochlea.[4]
B. biporus isoviparous, and the females lay one to foureggs in midsummer. The species only breeds underground. The eggs hatch after two months. The juveniles tend to be pink and then turn white as they grow into adulthood. Bipes Biporus don't exhibit sexual dimorphism so their sexual identity is only determined by looking at their gonads.[5]
The Mexican mole lizard (B. biporus) is found in the states ofBaja California,Baja California Sur,Guerrero andChiapas, inMexico. These species tend to be found on this peninsula near the sandy soils in desert with dry shrub land. They spend their time burrowed from 2.5cm to 15 cm.[citation needed]
Like all other amphisbaenians,B. biporus is aburrowing species that only surfaces at night or after heavy rain. It uses its autotomous tail as an escape tactic for predators. Losing a part of the tail while burrowing can plug up the hole behind it, giving it time to escape.
B. biporus is an opportunist carnivore and eatsants,termites, ground-dwellinginsects, larvae,earthworms, and small animals includinglizards. It usually pulls its prey underground to start its meal. The species is a generalist predator that feeds on easily accessible prey found in soil, debris, and dirt. Stomach content analyses showed that most prey items were soft-bodied and bore tooth marks, indicating that the lizard bit and chewed them rather than swallowing them whole.[6] Prey items are generally smaller in diameter than the gape of the individualB. biporus that consumed them.[7]
Human activity poses a significant threat to this species, alongside its natural predators, as is common among many species. Urban development and agricultural practices often result inhabitat destruction, particularly concerning as these creatures typically burrow at shallow depths. Among their natural predators, snakes pose a notable threat, particularly if they are larger in size and share the same habitat.[8]
this is one of the strangest, most mysterious reptiles on Earth (it technically isn't a lizard or a snake, but sits in a category all its own, the amphisbaenians), with powerful front limbs and rear limbs that have vanished save for vestigial bones you can only make out on X-rays.
