We’re inching closer to summer honest, even with all the fog, rain and snow we’re getting in this Frigid February. Last week we met the Plainfin Midshipman, a fish with a lot to say, as well as host of other noisy nautical beasties. This week’s issue is positively primeval, hope you guys enjoy.

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Issue #160 – Tuatara

Kingdom – Animalia

Phylum – Chordata

Class – Reptilia

Order – Rhynchocephalia

Family – Sphenodontidae

Genus – Sphenodon

Species – punctata

Related Species - In addition to S.punctata, there is one other extant member of the Order Rhynchocephalia; S.guntheri who like its close relative, is only found in New Zealand. (1)

Range

Third Eye Blind

Tuatara are medium sized reptiles, with adult males reaching an average body length of 60cm, and a weight of up to 1kg. While superficially similar looking to lizards such as agamas and iguanas, both species of Tuatara belong to an ancient lineage of reptiles that eventually became extinct due to competition with more advanced reptiles. Among not just reptiles, but all extant amniotes (a group consisting of reptiles, birds and mammals) the Tuatara holds the honour of being the most primitive member of this group (2). Despite being a reptile, the internal organs of Tuataras are more similar to amphibians, and this may explain why, of all reptiles, the Tuatara has the lowest optimal body temperature, at around 16°C.

Tuatara’s are carnivores, and hunt a variety of prey species ranging from invertebrates up to small lizards, frogs and birds. Once prey is caught, the Tuatara rips its victim apart by sliding its lower jaw backwards and forwards. This allows its rows of teeth, one row on the upper jaw and two on the lower, to act almost like a saw, and allow the reptile to rip through flesh until it’s in small enough chunks to swallow. Adult Tuatara’s have no native extant predators, but are preyed upon by a number of introduced species including rats (Rattus exulans), stoats (Mustela erminea) and domestic cats (Felis catus).

Tuatara’s mature and reproduce very slowly, with animals taking between 10 and 20 years to reach sexual maturity. Unlike lizards, male Tuatara don’t have a penis, and instead pass sperm to the female by pressing his cloacal vent against hers. After mating it may take up to three years for a shell and yolk to form on the fertilized eggs, and once laid and buried, it takes a further fifteen months for the eggs to hatch. Newly hatched Tuatara are largely diurnal, mostly to avoid meeting the adult members of their species, which are quite willing to cannibalize their progeny.

Five Fun Tuatara Facts

The name Tuatara translates from Maori to ‘Peaks on the Back’ a reference to the dorsal spines running down the animals back.

Tuatara are among the few vertebrates that possess a ‘third eye’ situated on the top of their heads and equipped with a lens, cornea, retina and nervous connection to the brain that detect changes in, and absorbs, light and Vitamin D Levels (3). Initially this eye is visible, but eventually scales grow over it.

Due to their slow growth rate, Tuatara’s have very long lifespans, with some individuals reaching over a century in age.

In addition to this, they are able to reproduce at an elderly age. A few years ago ‘Henry’ a 110 year old Tuatara who had never mated before, produced a healthy clutch of eleven eggs with his long-time partner ‘Mildred’ aged 80 (4).

Like lizards, if grabbed by the tail a Tuatara can break the vertebrae in the appendage and drop it to confuse predators.

Bibliography

1 -www.arkive.org

2 - Russell, Matt (August 1998). "Tuatara, Relics of a Lost Age". Cold Blooded News. Colorado Herpetological Society

3 - Thompson MB & Daugherty CH (1998). "Metabolism of tuatara, Sphenodon punctatus". Comparative Biochemistry and Physiology A. 119 (2): 519–522

4 - http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10553616

Picture References

1 - http://static.panoramio.com/photos/original/3863489.jpg

2 - https://upload.wikimedia.org/wikipedia/commons/thumb/7/7e/North_Island_Map_tuatara.PNG/220px-North_Island_Map_tuatara.PNG

3 - http://easyscienceforkids.com/wp-content/uploads/2013/04/Tuataras-eating.jpg

4 - http://2.bp.blogspot.com/_ArXjOKca5W8/TSrGOEfBKwI/AAAAAAAAAZc/RY26ThAiYiw/s1600/2.png

And that’s the three eyed, saw toothed, cold blooded cannibal known as the Tuatara, long may it grace us with its oddness, Next week’s issue requires us all to grab some arrows, a torch and a plane ticket to Brazil so we can swat the truth out of a certain animal. But until then make sure to critic, comment and suggest future issues as well as making sure you check past issues in Impurest’s Bestiary

Many Thanks

Impurest Cheese

Want more IGTA? For something equally draconic looking click here to check out the Australian Water Dragon. Or for actual dinosaur fun, click here to see the time I covered an honest to goodness ‘raptor’.