Lizards

Ranging in size from this European lizard found in the UK up to Komodo dragons, this is a large and varied family.

A hugely wide ranging family, with over 7000 species, they are well known. Oddly, snakes are actually a sub-family of lizards, but will be dealt with separately. With this many species, there is a large amount of variation, and any family tree looks very messy. As such I will set it up differently, and as pages are created they will be linked in the right place.

The first split in the tree is between Dibamia and Bifurcata. These branches are not evenly balanced. Dibamia contains just one family Dibamidae, which is the family of blind skinks. They have become elongated and look quite like a worm or a snake. Indeed, while males retain flap-like arms, females have completely lost any remaining sign that they once had limbs. This consists of 2 genus, Anelytropsis which only contains one species Anelytropsis papillosus and the genus Dibamus which contains 23 species. 

Given this family contains 7000 species it is likely that there will never be a page for each species, however when they do get created, they will be linked to the pictures below – so to view any pages that have been connected simply click on the corresponding photo.

Bifurcata is split into 2 families

Gekkota which is the Gecko family and contains 1000 species and Unidenta, which contains the rest of the family – known as Unidenta (look at next text box)

Unidenta is split in 2. One branch contains just one family Scincoformata – which is skinks and their closest relatives and Episquamata which contains the rest of the family (look at next text box)

Episquamata contains 2 groups: one branch contains Laterata which is a group of Squamate reptiles containing Lacertidae, Telidae, Gymnophthalmidae and Amphisbaenia the other branch is  Toxicofera (one who bears toxins)  which includes the rest of the family (look at next text box)

 

Toxicofera contain 2 different groups, one branch Serpentes – not considered to be lizards, and dealt with in a separate section (click here to reach the Snake page). This includes 3000 species. The other branch immediately splits and these 2 branches are Iguania ( iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids)  which  contain 1500 species and Anguimorpha (containing 350 species in 92 genera and in 12 families)

Muggar Crocodile

Muggar Crocodile

Found in fresh water, across India and as far away as Iran, as well as small parts of its range extending into various neighbouring countries including Pakistan, Nepal and Sri Lanka.

As to be expected, its closest relations are the other Asiatic and Australasian Crocodile species.

Its greatest threat is habitat loss and is listed as CITES appendix i. In 2013 the wild population was estimated at 8700, with no single population being over 1000. Between 1970 and 1990 over 1000 were bred in captivity and released into 28 protected areas, however this program was shut down by the government.

 

False Gharial

False Gharial

False Gharial

The false gharial (Tomistoma schlegelii), also known by the names Malayan gharial, Sunda gharial and tomistoma is a freshwater crocodilian of the family Gavialidae native to Peninsular MalaysiaBorneoSumatra and Java. It is listed as Vulnerable on the IUCN Red List, as the global population is estimated at around 2,500 to 10,000 mature individuals.

Perhaps what is clear from this is the need to know the population more accurately, as there is a big difference between 2500 and 10000. Having said this, what is clear is that this is a crocodillian that is in a much safer position than many of its cousins.

While rare, there have been 3 fatal attacks on humans since 2000. While before this there were no documented cases, this may be down to record keeping rather than actual facts.

It is considered appendix i and its distribution is very broken which can be a great threat to a species. What will happen in the future is still unclear.

Gharial

Gharial

Gharial

Also know as the Gavial or fish-eating crocodile, and is one of the longest crocodilians with females 2.6-4.5m and males 3-6m long. It currently lives in rivers in the northern half of India, and is one of the most aquatic crocodilian, only leaving water to lay eggs and to sunbathe.

Rapid declines in 1930 have left them occupying only 2% of their former range, with a captive breeding program having run since the 1980s to reintroduce them to their former range. It has been listed as critically endangered since 2007.

The global population in 2007 (last full survey) was 900. Much work is going on with reintroduction projects in India, Bangladesh and Nepal.

Osborn Dwarf Crocodile

Osborn dwarf crocodile (Congo Dwarf Crocodile) Photo credit marius Burger CC0

Osborn Dwarf Crocodile

Endemic only to the Congo basin in Africa, it was originally described as a separate species in 1948. In 1961, it was downgraded to subspecies level and just 2 years ago it was found to be distinct enough to be full separate species.

They are on CITES appendix 1, but little is known about their status.

Below is a short video on this and the other dwarf crocodile

African Dwarf crocodile

African dwarf crocodile

The dwarf crocodile (also known as the African dwarf crocodile, broad-snouted crocodile -a name more often used for the Asian mugger crocodile) or bony crocodile), is an African crocodile that is also the smallest living species of crocodile.

Found in lowlands to mid-height areas, in small and mid-size streams (they avoid large rivers). Generally, they live in rivers that lie in rainforest, though they will venture into the open.

They are known, in places, to be found in pools deeply isolated in Savannah. In western Gabon, there are also a group which have been living long-term in caves. It is considered vulnerable by the IUCN and is Appendix i of CITES. Where they are declining, it appears largely as a result of deforestation and hunting for the bushmeat trade. As a result, while in some regions they have a healthy population, in others (like Gambia and Liberia) they are almost lost.

In zoos in the USA and Europe there are a few of this species, however, records are not good, and quite a few of them are clearly hybrids with little conservation use. I should note, a zoo I occasionally volunteer at (marwell zoo) had one of these crocodiles until last year when it went to another zoo for breeding.

We hope to be able to list places for you to visit to see this species as soon as possible. Any of these will appear below the video and the news section (this lists all the times that this species has been mentioned (if any) in this blog). Below this, we will list all the easiest places we have connections to, to see this species.

 

Western Slender snouted crocodile

Western slender snouted crocodile Photo credit Thesupermat CC by SA 3.0

Western Slender snouted crocodile

Green is the western slender snouted crocodile range

Similar to the Central slender snouted crocodile (which was only clearly found to be separate in 2018). Like its cousin, it has a very pointed nose, which it uses to eat small fish and invertebrates. Males reach 3m-4m in length, and weigh between 125kg and 325kg.

Generally recognized as data deficient, the numbers are certainly low. When the two slender snouted crocodile species were thought to be one, they were classed as critically endangered, so it is unlikely that either has a more healthy population.

Clearly more information is needed.

They still are found in parts of Ghana,but a recent genetic study in USA zoos found that a number of their slender snouted crocodiles were of this species, giving greater hope. There is an effort to breed them in captivity.

What is clear is that more information is required. I have been unable to find a video of this species, but the central slender snouted crocodile was considered the same species until recently and looks similar, visit that page here

Central African Slender snouted crocodile

Central African Slender snouted crocodile

Before several studies that occurred one in 2014 and the other in 2018, it was thought that there was only one species of slender snouted crocodile – the west African slender snouted crocodile.

Central African slender-snouted crocodile occurs widely in Central Africa (Cameroon, Equatorial Guinea, Gabon, northern Angola, Central African Republic, Republic of the Congo, Democratic Republic of the Congo) and extends into South Sudan, and Lake Tanganyika in East Africa.

No-one has been able to find out their status, but they are clearly not healthy as a population, and given its habitat is being destroyed, it is likely still reducing.

Below is a short video of one encountered in the wild in Gabon.

West African Crocodile

West African Crocodile

The West African crocodile inhabits much of West and Central Africa, ranging east to South Sudan and Uganda, and south to Democratic Republic of the Congo (in all three countries it may come into contact with Nile crocodiles). Other countries where it is found include Mauritania, Benin, Liberia, Guinea-Bissau, Nigeria, Niger, Cameroon, Chad, Sierra Leone, Central African Republic, Equatorial Guinea, Senegal, Mali, Guinea, Gambia, Burkina Faso, Ghana, Gabon, Togo, Ivory Coast and Republic of Congo. Just 100 years ago, museums were still getting specimens from the southern Nile but they appear to be long lost from this part of their range.

Bizarrely, it survives in desert conditions in Mauritana, largely by staying in caves and burrows in the driest periods, and then emerging in rainy periods.

It was only recognized as a separate species in 2010 which has lead to its poor representation in zoos. Having said that, a surprising number of pure members of this species has been found. There are breeding pairs in around 4 uk zoos. A study of 16 so-called Nile crocodiles in 6 USA zoos found all but one were actually west african Crocodiles.

Clearly more work is needed on this species, as well as its captive population.

Siamese Crocodile

Siamese Crocodile

This is a freshwater species found in all kinds of freshwater ways, within its range. It is 2.1-3m as an adult and weighs between 40-120kg.

It is critically endangered, and is considered appedix i of CITES. It is highly endangered in the wild, though there is a healthy captive population. Given, it was considered extinct in the wild back in 1992 so it has improved.

There is currently a not insubstantial population, though it is heavily fragmented across its range. As such, until the population has greatly improved, it is likely to require substantial effort from humans with regular translocations between different places. This way, the whole species can be considered a mega population, and the genetic variability can be kept high, until the population recovers. Poaching is common, where they are put in breeding farms and hybridized with other large crocodile species.

There are various places where good conservation could rapidly change the situation. They are thought to roam Java and Kalimantan, but surveys are essential to work out if this rumour is true or not. if they have held on, these forgotten habitats may prove a safer nursery than elsewhere.

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