Friday, 21 May 2010

Squamates Part II

Part two of the lizards, featuring members of the families Crotaphytidae, Gekkonidae, Helodermatidae, Iguanidae, Lacertidae, Phrynosomatidae, and Polychrotidae.

Male (above) and female brown anoles
Anolis sagrei Dumeril & Bibron, 1837 - Polychrotidae
Wild in Orlando, Florida
July 2007

Anoles are a group of lizards related to iguanas, indeed they are sometimes placed within the same family. They are distributed in subtropical and tropical parts of the Americas, including most Caribbean islands. The brown anole is native to Cuba and the Bahamas, and has been introduced to the USA. I saw no other species of lizard in my two weeks in Florida in 2007 (except the other alien, see below), but brown anoles abound. The male, as can be seen in the top photo, flashes a colourful dewlap of skin at mates and rivals.

Blue spiny lizard
Sceloporus serrifer cyanogenys (Cope, 1885) - Phrynosomatidae
London Zoo
December 2009

Spiny lizards are related to the horned toads - not toads, but they are somewhat reminiscent of those amphibians. I'm not sure if the spiny lizards can do this, but the horned toads are able to squirt blood from around their eye into the face of a potential predator, which is supposedly enough to deter most of them.

Juvenile Schreiber's fringe-toed lizard
Acanthodactylus schreiberi Boettger, 1878 - Lacertidae
Wild at Alagadi Beach, North Cyprus
April 2009

The fringe-toed lizards of the genus Acanthodactylus ('thorn finger') are distributed in arid habitats in parts of northern Africa, southern Europe, and southwest Asia. This species is found in Cyprus and adjacent parts of Turkey and the Near East. It is abundant, although it is classed as Endangered by the IUCN. Juveniles have bright red tails which fade as they mature; their striped bodies also fade. They aren't difficult to spot, but they are hard to approach. More pictures available on the ARKive website (submitted by myself!).

Snake-eyed lizard
Ophisops elegans Menetries, 1832 - Lacertidae
Wild at Geçitköy Reservoir, North Cyprus
April 2009

Although outwardly quite similar to the Schreiber's fringe-toed lizard, the snake-eyed lizard is less abundant, and just as shy. The eye is likened to that of a snake because it appears to lack eyelids, but they are really just clear and fused together, forming a protective 'spectacle'. As well as being found on Cyprus, it is distributed throughout much of the Middle and Near East, and as far east as India.

Troodos lizard
Phoenicolacerta troodica (Werner, 1936) - Lacertidae
Wild in Kyrenia, North Cyprus
April 2009

This species is endemic to Cyprus, but has close relatives in mainland Turkey and the Near East. It was until recently considered a member of the genus Lacerta, but this widespread genus has been broken down into several genera. The Troodos lizard bears similarities to the ocellated lizard (Timon lepidus) and green lizards (Lacerta spp.), and the male in the breeding season has a blue, green, and rufous coloration.

Utila spiny-tailed iguana
Ctenosaura bakeri Stejneger, 1901 - Iguanidae
London Zoo
December 2009

This is a critically endangered, medium-sized, tree-dwelling iguana endemic to the island of Utila off the coast of Honduras in Central America. Its tail has encircling bands of spines, hence the name.

Rhinoceros iguana
Cyclura cornuta Bonnaterre, 1789 - Iguanidae
Colchester Zoo
June 2009

There are many large species of iguanas found on islands: the marine iguana (Amblyrhynchus cristatus) is the only sea-dwelling lizard, and there are pink land iguanas on the Galapagos Islands, and blue ones in the Cayman Islands. The island of Hispaniola, shared between Haiti and the Dominican Republic, in the Caribbean Sea, is home to the rather large rhinoceros iguana. They are vulnerable to extinction, but thankfully are doing well in captive breeding programmes worldwide.

Male green iguana
Iguana iguana (Linnaeus, 1758) - Iguanidae
Wild in Everglades National Park, Florida
August 2007

I spotted this individual in a tree while walking along the Anhinga Trail in the Everglades. I did not expect to see this. It is well known that stupid people set their pets free (I once did this, I am ashamed to admit... it too involved illegal aliens, American bullfrogs - Lithobates catesbeiana... oops!), so it should be no surprise that all sorts of exotic creatures can be found in the subtropical climes of the Everglades.

Male (foreground) and female Fijian banded iguanas
Brachylophus fasciatus (Brongniart, 1800) - Iguanidae
Manchester Museum
July 2008

There are three species of iguana native to the islands of Fiji in the South Pacific Ocean, all of the genus Brachylophus. They are all severely threatened with extinction; one species, B. bulabula, was only described in 2008. The Fijian banded iguana differs from the similar crested iguana (B. vitiensis) by its shorter crest and bluer coloration.

Mexican beaded lizard
Heloderma horridum Wiegmann, 1829 - Helodermatidae
Paradise Wildlife Park, Broxbourne, Hertfordshire
September 2009

There are two species in the family Helodermatidae - the Gila monster (H. suspectum - see below), and the Mexican beaded lizard. Both are notorious for being the only North American lizards with a venomous bite. They also share this beaded texture to their scales, giving this species its name.

Gila monster
Heloderma suspectum Cope, 1869 - Helodermatidae
London Zoo
June 2007

The Gila (pronounced "hee-la") monster is not as monstrous as its name suggests. It is a placid animal and will only bite if provoked. Indeed, because it uses its venom to subdue and kill its prey, it will not waste it on stupid humans unless absolutely necessary. It has been discovered that certain compounds in the venom of Heloderma lizards have anti-diabetic properties - this is something which has earned the Gila monster and Mexican beaded lizard some good form of notoriety.

Madagascar giant day gecko
Phelsuma madagascariensis grandis Gray, 1870 - Gekkonidae
Natural History Museum, London
May 2009

Geckos are another type of lizard familiar to most people - they are widespread in most warm parts of the world, some make excellent pets, and are reknowned for their ability to climb walls and ceilings with ease. The day geckos of the genus Phelsuma are found in Madagascar, so called because of their diurnal activity.

Leopard gecko
Eublepharis macularius Blyth, 1854 - Gekkonidae
Cambridge Zoology Museum
May 2009

Most geckos have no true eyelids - the scales which form the eyelid have fused (see snake-eyed lizard above). The eublepharines are a subfamily of geckos which possess true eyelids. They also lack the adhesive pads on their toes. The leopard gecko is a very popular pet - it originates from arid and semi-arid regions of southern Asia.

Male collared lizard
Crotaphytus collaris (Say, 1823) - Crotaphytidae
Crews Hill, Enfield
May 2009

Collared lizards are rarely seen in the pet trade, but are common in arid habitats in the west of the USA and Mexico. Males have the triple black collar on the neck which gives the species its vernacular and specific names. The colours become bolder and brighter during the breeding season.

More lizards (and perhaps some mosasaurs!) coming up soon...


Zachary said...

I've heard that gila monsters, if caught out in the open, are fairly easy to catch and aren't so much aggressive as heavy and squirmy. Still, the way they inject venom is pretty nasty: the venom is pumped into the saliva, and the lizard actually chews its victim to work the venom in.

Mo Hassan said...

Yes, that sounds rather nasty!