"Love means loving the unlovable,
or it is no virtue at all."

    Heretics

    Gilbert Keith Chesterton (1874-1936)

    Catholic apologist, essayist, novelist, and poet

 

Puerto Rican many-ringed amphisbaena, Amphisbaena bakeri. Maricao State Forest, western Puerto Rico.

 


 

Lurkers Underground

 

ORDER AMPHISBAENIA

 

    Amphisbaenians, sometimes called "worm lizards" (perhaps a name better reserved for the gymnophthalmids - see the section on lizards) were until recently considered to be legless lizards. However, they are now placed their own taxonomic order, Amphisbaenia, apart from lizards and snakes. These are indeed weird, fascinating animals.

    They might be distantly related to teiids (tegus, whiptails, ameivas, etc.). Their generic name comes from the Greek, "that which walks in two directions", for their capacity to move equally forward and backward both inside their subterranean burrows as well as above ground. The name also makes allusion to the fact that it is quite difficult at first glance to tell which end of the animal is which, since the stubby tail resembles the head. The name also makes poetic reference to the mythical Amphisbaena, a snake-like moster with a head at both ends.


 

At first glance, the head and tail of an amphisbaenid look alike.

First photograph: Virgin Island's amphisbaena, Amphisbaena fenestrata. Crown Mountain, central Saint Thomas, United States Virgin Islands.

Second photograph: Puerto Rican xeric amphisbaena, Amphisbaena xera. Guanica State Forest, south-western Puerto Rico.

 

    As an adaptation for their chthonic existence, the bones of their skulls and jaws are heavy, solid, and partially fused together. They use their heads for shoveling soil and tunneling under rocks, roots, and fallen logs. They are seldom seen above ground, and even then only at night or when torrential rains flood their lairs. Like snakes, they are mostly deaf to airborne sounds, but are highly sensitive to vibrations in the substrate, and their protractible bifid tongues help them enhance their strong sense of smell. The members of the Mexican family Bipedidae (four species) is unique among all extant reptiles in having only forelegs. The skins of amphisbaenians are loosely attached to the body, and they move in an accordion fashion. With their elongated but stout bodies surrounded by rings of squarish scales, their inconspicuous eyes, and their usually gray, cream, or pink colors, these strange reptiles resemble fat earthworms. Their vestigial eyes are useless except to distinguish between light and dark, but can nonetheless be noticed under the translucent skin of their heads.


     West Indian members of this order belong to the families Amphisbaenidae and Cadeidae.

A Virgin Islands amphisbaena, Amphisbaena fenestrata, uses its head as a shovel in order to burrow underground.

Crown Mountain, central Saint Thomas, United States Virgin Islands.

 

Family Amphisbaenidae: Typical Amphisbaenas


    This group is present in Africa, South America, and in the West Indies they are found in the Greater Antillean island banks, except for Jamaica's. Only the genus Amphisbaena is present in this region. Cuba has three species, Hispaniolan has seven, and Puerto Rico is inhabited by five species. It is probable that more await discovery.


Hispaniolan dwarf amphisbaena, Amphisbaena manni. Bani, south-western Dominican Republic Hispaniola.

(Photographs courtesy of Mr. Miguel Angel Landestoy).

 

    As happens with the blind burrowing snakes like Typhlops and Leptotyphlops, the diverse species of amphisbaenas are very difficult to tell apart at first glance. They all look extremely similar to one another, and one often has to look closely at their head squamation or count body annuli to be identified.

 

Puerto Rican xeric amphisbaena, Amphisbaena xera. Guanica State Forest, south-western Puerto Rico.

This species is limited in its distribution to the dry, south-western region of the island.

 

    Amphisbaenas are small but fierce predators capable of biting off pieces from any small animal that crosses their path, and then swallowing them with the help of their short and muscular tongues. They occasionally eat carrion, as well. Many don't hesitate to bite when handled and, although indeed their teeth are very sharp and their jaw muscles are enormously strong for their size, none except the largest species can inflict any serious pain on a human hand. All the same, even rather small species can draw some blood, delivering quite a pinch by fastening to a finger with bulldog-like tenacity, and then twisting their bodies around, seemingly with every intention of ripping off as big a chunk of flesh as possible.

 


Virgin Islands' amphisbaenas, Amphisbaena fenestrata. Crown Mountain, central Saint Thomas, United States Virgin Islands.

This species is one of the very few vertebrates endemic to this group of small islands, easternmost part of the Puerto Rican bank.

 

Puerto Rican many-ringed amphisbaena, Amphisbaena bakeri. Maricao State Forest, western Puerto Rico.

Its distribution is restricted to the mesic karstic and serpentine forests of western Puerto Rico.

Puerto Rican common amphisbaenas, Amphisbaena caeca.

First two photographs: Utuado, central Puerto Rico.

Third photograph: Forth Buchanan, Gaynabo, north-eastern Puerto Rico.

Amphisbaenas may have egregiously rotten tempers, and often bite as soon as they are held in hand.

The spots on the body and head of this individual are bite scars earned during squabbles with others of its kind.

Of course, such battles are almost never witnessed by people, since they happen underground.

 

Puerto Rican dusky amphisbaena, Amphisbaena schmidti. Florida, central Puerto Rico.


Family Cadeidae: Cuban Amphisbaenas

    Although they strongly resemble typical amphisbaenas, Cadea belongs to a different family that seems to have arrived in the New World via trans-atlantic dispersal from Africa or Europe. Wherever they happened to land at first in the Americas, today the family of two known species seems to be
found exclusively on Cuba.


Cuban spotted amphisbaena, Cadea blanoides. Havana, north-western Cuba.
(Photograph courtesy of Mr. Joseph Burgess).

Cuban spotted amphisbaena, Cadea blanoides, with two eggs. Viñales, Pinar del Rio, north-western Cuba.

(Photograph courtesy of Dr. S. Blair Hedges).