---
title: "What the sources say about the Tuatara | AnimalTracks.wiki"
description: "64 claims from the Tuatara profile, each beside the words of the source that backs it."
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canonical: "https://animaltracks.wiki/animals/tuatara/sources/"
---

# What the sources say about the Tuatara (*Sphenodon punctatus*)

> 64 claims from the Tuatara profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Tuatara](https://animaltracks.wiki/animals/tuatara/)

## Tuatara. New Zealand Department of Conservation.

https://www.doc.govt.nz/nature/native-animals/reptiles-and-frogs/tuatara/

| The page says | The source says |
| :--- | :--- |
| usually shared with colonies of breeding seabirds | The islands are usually occupied by colonies of breeding seabirds. |
| Mostly beetles, wētā, worms, millipedes and spiders, with the rest made up of lizards, seabird eggs and chicks | Their diet consists primarily of invertebrates, such as: beetles wētā worms millipedes and spiders. The remainder of what they eat is made up of lizards, seabird eggs and chicks. |
| Adult males are about half a metre long and weigh up to 1.5 kilograms when fully grown | Adult males are about 0.5 metres in length, and weigh up to 1.5 kg when fully grown. |
| a crest of spines along the neck and down the back that a male can raise to attract females or when fighting other males | The male has a distinctive crest of spines running along the neck and down the back. He can erect these spines to attract females or when fighting with other males. |
| A tuatara keeps growing until it is about 35 years old | They keep growing until they are about 35 years old. |
| its average life span is about 60 years, though it can live up to 100 | A tuatara's average life span is about 60 years, but they can live up to 100 years. |
| The diet is mostly invertebrates such as beetles, wētā, worms, millipedes and spiders, and the rest is lizards, seabird eggs and chicks | Their diet consists primarily of invertebrates, such as: beetles wētā worms millipedes and spiders. The remainder of what they eat is made up of lizards, seabird eggs and chicks. |
| In the wild, tuatara now survive on only 32 islands | Tuatara once lived throughout mainland New Zealand but now only survive in the wild on 32 islands. (note: current DOC web page; the 2020 genome paper and 2017 abstract also give 32 islands) |
| Rats are considered their most serious threat | Rats are considered the most serious threat to the survival of tuatara |
| there were probably few, if any, tuatara left on the North and South Islands by the time European settlers arrived | There were probably few, if any, tuatara left on the North and South Islands by the time European settlers arrived in New Zealand. |
| that was dropped in 2009 | A second species Sphenodon guntheri was recognised in 1989 but discontinued in 2009 when research concluded tuatara is best described as one species. |
| puts the average at about 60 years, with a maximum of up to 100 | A tuatara's average life span is about 60 years, but they can live up to 100 years. |
| tuatara have one of the slowest growth rates of any reptile | Tuatara have one of the slowest growth rates of any reptile. |
| keeps growing until it is about 35 years old | They keep growing until they are about 35 years old. |
| one of the slowest growth rates of any reptile. | Tuatara have one of the slowest growth rates of any reptile. |

## Tuatara. San Diego Zoo Wildlife Alliance.

https://animals.sandiegozoo.org/animals/tuatara

| The page says | The source says |
| :--- | :--- |
| a nocturnal New Zealand islander | unlike lizards, tuataras are nocturnal |
| a light-sensitive third eye it does not see with | The unique eye is sensitive to light |
| A light-sensitive third eye with a retina and lens | The "eye" has a retina, lens, and nerve endings, yet it is not used for seeing. |
| It looks like a lizard, but it is not one | Although it looks like a lizard, it is really quite different. (note: not-a-lizard also follows from the genome paper's divergence of the tuatara lineage from all squamates) |
| In managed care, the San Diego Zoo gives a life span of up to 91 years | Up to 91 years in managed care |
| On top of the head, a tuatara has a third eye with a retina, lens and nerve endings | their most curious body part is a "third eye" on the top of the head. The "eye" has a retina, lens, and nerve endings |
| It isn't used for seeing. | yet it is not used for seeing |
| In young tuatara it shows through the skin, but within a few months scales and pigment cover it, making it hard to spot | It is visible under young tuataras’ skin but becomes covered with scales and pigment in a few months, making it hard to see. |
| The eye is sensitive to light and may help the tuatara judge the time of day or the season | The unique eye is sensitive to light and may help the tuatara judge the time of day or season. |
| A tuatara's upper jaw carries two rows of teeth, and the one row on the lower jaw fits between them when the mouth is closed | There are two rows of teeth on the upper jaw and one row on the lower jaw that fits between the upper rows of teeth when the mouth is closed. |
| Lost or broken teeth are not replaced, and older tuatara have to eat softer food as their teeth wear down | These small teeth are not replaced when lost or broken, and older tuataras have to eat softer food items as their teeth wear down. |
| The Brothers Island tuatara was once treated as a second species, *Sphenodon guntheri* | it was initially decided that the Brothers Island tuatara was a separate species ( Sphenodon guntheri ) |
| it contains a retina and a lens, but the tuatara does not use it for seeing | The "eye" has a retina, lens, and nerve endings, yet it is not used for seeing. |
| It does react to light, which may help the animal tell what time of day or season it is | The unique eye is sensitive to light and may help the tuatara judge the time of day or season. |
| Two Rows of Teeth, One Shearing Bite | There are two rows of teeth on the upper jaw (note: heading; shearing bite is claimed from the 1982 mastication abstract) |

## Gemmell et al. (2020). The tuatara genome reveals ancient features of amniote evolution. Nature.

https://doi.org/10.1038/s41586-020-2561-9

| The page says | The source says |
| :--- | :--- |
| The sole survivor of an ancient reptile order | the only living member of the reptilian order Rhynchocephalia (Sphenodontia) |
| the lowest optimal body temperature of any reptile, 16 to 21 degrees Celsius | notable for having the lowest optimal body temperature of any reptile (16–21 °C) |
| the only living member of an entire reptile order, Rhynchocephalia | the only living member of the reptilian order Rhynchocephalia (Sphenodontia) |
| the tuatara lineage split from the branch that led to every living lizard and snake around 250 million years ago | the divergence of the tuatara lineage from all squamates (lizards and snakes) during the early part of the Triassic period at about 250 million years ago |
| was widespread across Gondwana | once widespread across Gondwana |
| its last fossils outside New Zealand dating to about 70 million years ago | the most recent fossil record outside of New Zealand is from Argentina in the Late Cretaceous epoch (about 70 Ma) |
| A 2020 genome study put the global population at around 100,000 | The current global population is estimated to be around 100,000 individuals. (note: 2020 is the reference's publication year (Gemmell et al. 2020); dated to the paper so the figure does not read as a 2026 count) |
| Lizards and snakes make up the squamates | all squamates (lizards and snakes) |
| dates the tuatara lineage's split from them to about 250 million years ago, early in the Triassic | the divergence of the tuatara lineage from all squamates (lizards and snakes) during the early part of the Triassic period at about 250 million years ago |
| The tuatara belongs to a separate order, Rhynchocephalia, and is its only living member | the only living member of the reptilian order Rhynchocephalia (Sphenodontia) |
| a 2020 study of the tuatara genome | Here we analyse the genome of the tuatara (note: 2020 is the reference's publication year (Gemmell et al. 2020)) |

## Sphenodon punctatus. Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Sphenodon_punctatus/

| The page says | The source says |
| :--- | :--- |
| Islands off the coast of New Zealand, generally cliff-bound and windswept | The islands are generally cliff-bound, frequently exposed to strong winds |
| On windswept islands off New Zealand | frequently exposed to strong winds |
| The tuatara has been falsely called a living fossil. | The tuatara has been falsely called a living fossil. |
| Its teeth are fused to the jawbone | the tuatara's teeth are fused to the jaw bone (acrodont tooth structure) |
| Nobody has pinned it down | the function has not been clearly recognized |
| Known as the parietal eye | posess a "parietal eye" on the top of their head |

## Meloro & Jones (2012). Tooth and cranial disparity in the fossil relatives of Sphenodon (Rhynchocephalia) dispute the persistent 'living fossil' label. Journal of Evolutionary Biology.

https://doi.org/10.1111/j.1420-9101.2012.02595.x

| The page says | The source says |
| :--- | :--- |
| Rhynchocephalia once held a much greater diversity of forms | the group to which it belongs included a much greater diversity of forms in the Mesozoic |
| is not the product of evolutionary stasis | the tuatara is not the product of evolutionary stasis but that it represents the only survivor of a diverse Mesozoic radiation whose subsequent decline remains to be explained |
| the only survivor of a diverse Mesozoic radiation whose decline remains unexplained | represents the only survivor of a diverse Mesozoic radiation whose subsequent decline remains to be explained |

## Herrera-Flores, Stubbs & Benton (2017). Macroevolutionary patterns in Rhynchocephalia: is the tuatara (Sphenodon punctatus) a living fossil? Palaeontology.

https://doi.org/10.1111/pala.12284

| The page says | The source says |
| :--- | :--- |
| The label has often been applied because of the tuatara's apparent close resemblance to its Mesozoic forebears | has often been noted as a classic ‘living fossil’ because of its apparently close resemblance to its Mesozoic forebears |
| A 2017 study that put the label to a formal test came out in its favour | We provide a testable definition for ‘living fossils’ based on a slow rate of lineage evolution and a morphology close to the centroid of clade morphospace. (note: 2017 is the reference's publication year (Herrera-Flores, Stubbs & Benton 2017)) |
| the living tuatara did evolve unusually slowly, and its anatomy sits near the centre of the range of forms seen across all Rhynchocephalia | the extant tuatara underwent unusually slow lineage evolution, and is morphologically conservative, being located near the centre of the morphospace for all Rhynchocephalia |
| The label has been disputed because the tuatara's Mesozoic relatives were widely diverse and because the living tuatara has adaptations of its own | This designation has been disputed because of the wide diversity of Mesozoic forms and because of derived adaptations in living Sphenodon. |
| defined a living fossil by a slow rate of lineage evolution and a form near the middle of its group's range | We provide a testable definition for ‘living fossils’ based on a slow rate of lineage evolution and a morphology close to the centroid of clade morphospace. |
| found the tuatara meets both tests | the extant tuatara underwent unusually slow lineage evolution, and is morphologically conservative, being located near the centre of the morphospace for all Rhynchocephalia |
| A 2017 study defined a living fossil | We provide a testable definition for ‘living fossils’ (note: 2017 is the reference's publication year (Herrera-Flores, Stubbs & Benton 2017)) |
| tags: living-fossil | the extant tuatara underwent unusually slow lineage evolution, and is morphologically conservative, being located near the centre of the morphospace for all Rhynchocephalia |

## Hay et al. (2009). Genetic diversity and taxonomy: a reassessment of species designation in tuatara (Sphenodon: Reptilia). Conservation Genetics.

https://doi.org/10.1007/s10592-009-9952-7

| The page says | The source says |
| :--- | :--- |
| a genetic study concluded that tuatara is best described as a single species with distinctive geographic variants | we conclude that, contrary to current taxonomy, Sphenodon is best described as a single species that contains distinctive and important geographic variants |

## Gorniak, Rosenberg & Gans (1982). Mastication in the tuatara, Sphenodon punctatus (reptilia: Rhynchocephalia): Structure and activity of the motor system. Journal of Morphology.

https://doi.org/10.1002/jmor.1051710307

| The page says | The source says |
| :--- | :--- |
| a sliding jaw that makes a shearing bite | allows the animal to use its short teeth in an effective shearing bite that cuts fragments off large prey |
| After a closing, crushing bite | Food reduction consists of a closing, crushing bite followed by a propalineal sliding of the dentary row between the maxillary and palatine ones. (note: sequence is the source's own: 'a closing, crushing bite followed by a propalineal sliding') |
| the lower tooth row slides forward between the upper rows in a propalineal movement | It is followed by a propalineal anterior displacement |
| giving a shearing bite that cuts fragments off large prey | allows the animal to use its short teeth in an effective shearing bite that cuts fragments off large prey |

## Hitchmough (2019). Sphenodon punctatus. The IUCN Red List of Threatened Species 2019: e.T131735762A120191347.

https://doi.org/10.2305/iucn.uk.2019-2.rlts.t131735762a120191347.en

| The page says | The source says |
| :--- | :--- |
| Least Concern | IUCN Red List category: Least Concern (LC). (note: conservationStatus in stats; category read through GBIF's copy of the Red List, per source pack; iucnredlist.org refuses scripts so this is the checked category, not the assessment text) |