Tuatara (''Sphenodon punctatus'') are
reptile
Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...
s
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
. Despite their close resemblance to
lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s, they are part of a distinct lineage, the order
Rhynchocephalia
Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a diverse g ...
.
The name ''tuatara'' is derived from the
Māori language
Māori (), or ('the Māori language'), also known as ('the language'), is an Eastern Polynesian language spoken by the Māori people, the indigenous population of mainland New Zealand. Closely related to Cook Islands Māori, Tuamotuan, and ...
and means "peaks on the back".
The single extant
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of tuatara is the only surviving member of its order.
Rhynchocephalians originated during the
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
(~250 million years ago), reached worldwide distribution and peak diversity during the
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
and, with the exception of tuatara, were extinct by
60 million years ago.
Their closest living relatives are
squamates
Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, i ...
(lizards and
snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
s). For this reason, tuatara are of interest in the study of the evolution of lizards and snakes, and for the reconstruction of the appearance and habits of the earliest
diapsid
Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years ago ...
s, a group of
amniote
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are disti ...
tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
s that also includes
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s (including
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s) and
crocodilian
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...
s.
Tuatara are greenish brown and grey, and measure up to from head to tail-tip and weigh up to
with a spiny crest along the back, especially pronounced in males. They have two rows of teeth in the upper jaw overlapping one row on the lower jaw, which is unique among living species. They are able to hear, although no external ear is present, and have unique features in their skeleton, some of them apparently evolutionarily retained from fish.
Tuatara are sometimes referred to as "
living fossil
A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossi ...
s",
which has generated significant scientific debate. This term is currently deprecated among paleontologists and evolutionary biologists. Although tuatara have preserved the morphological characteristics of their Mesozoic ancestors (240–230 million years ago), there is no evidence of a continuous fossil record to support this.
The species has between 5 and 6 billion
base pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...
s of
DNA sequence
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
, nearly twice that of humans.
The tuatara (''Sphenodon punctatus'') has been protected by law since 1895. A second species, the Brothers Island tuatara ''S. guntheri'', , was recognised in 1989,
but since 2009 it has been reclassified as a subspecies (''S.p. guntheri'').
Tuatara, like many of New Zealand's native animals, are threatened by habitat loss and introduced predators, such as the
Polynesian rat
The Polynesian rat, Pacific rat or little rat (''Rattus exulans''), known to the Māori as ''kiore'', is the third most widespread species of rat in the world behind the brown rat and black rat. The Polynesian rat originated in Southeast Asia, a ...
''(Rattus exulans)''. Tuatara were extinct on the mainland, with the remaining populations confined to 32 offshore islands
until the first North Island release into the heavily fenced and monitored
Karori Wildlife Sanctuary
Zealandia, formerly known as the Karori Wildlife Sanctuary, is a protected natural area in Wellington, New Zealand, the first urban completely fenced ecosanctuary, where the biodiversity of 225 ha (just under a square mile) of forest is being r ...
(now named "Zealandia") in 2005.
During routine maintenance work at Zealandia in late 2008, a tuatara nest was uncovered,
with a hatchling found the following autumn. This is thought to be the first case of tuatara successfully breeding in the wild on New Zealand's North Island in over 200 years.
Description
![Tuatara scale](https://upload.wikimedia.org/wikipedia/commons/1/1d/Tuatara_scale.png)
Tuatara are the largest reptile in New Zealand. Adult ''S. punctatus'' males measure in length and females .
Tuatara are
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
, males being larger.
The
San Diego Zoo
The San Diego Zoo is a zoo in Balboa Park, San Diego, California, housing 4000 animals of more than 650 species and subspecies on of Balboa Park leased from the City of San Diego. Its parent organization, San Diego Zoo Wildlife Alliance, is a p ...
even cites a length of up to . Males weigh up to , and females up to .
Brother's Island tuatara are slightly smaller, weighing up to 660 g (1.3 lb).
Their lungs have a single chamber with no
bronchi
A bronchus is a passage or airway in the lower respiratory tract that conducts air into the lungs. The first or primary bronchi pronounced (BRAN-KAI) to branch from the trachea at the carina are the right main bronchus and the left main bronchus. ...
.
The tuatara's greenish brown colour matches its environment, and can change over its lifetime. Tuatara shed their skin at least once per year as adults,
and three or four times a year as juveniles. Tuatara sexes differ in more than size. The spiny crest on a tuatara's back, made of triangular, soft folds of skin, is larger in males, and can be stiffened for display. The male abdomen is narrower than the female's.
Skull
The ancestor of
diapsids
Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years ago ...
had a
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
with two openings in the temporal region – upper and lower
temporal fenestra
A fenestra (fenestration; plural fenestrae or fenestrations) is any small opening or pore, commonly used as a term in the biological sciences. It is the Latin word for "window", and is used in various fields to describe a pore in an anatomical st ...
on each side of the skull bounded by complete arches. The upper jaw is firmly attached to the posterior of skull.
This makes for a very rigid, inflexible construction. The skull of the tuatara has a similar structure, with both upper and lower temporal openings.
However, the lower temporal bar (sometimes called the cheek bone) is incomplete in some fossil Rhynchocephalia, suggesting its presence in the tuatara is a distinctive (
autapomorphic
In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...
) feature rather than one inherited from a common ancestor.
The tip of the upper jaw is beak-like and separated from the remainder of the jaw by a notch.
There is a single row of teeth in the lower jaw and a double row in the upper, with the bottom row fitting perfectly between the two upper rows when the mouth is closed.
This specific tooth arrangement is not seen in any other reptile;
although most
snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
s have a double row of teeth in their upper jaws, their arrangement and function is different from the tuatara's.
The structure of the jaw joint allows the lower jaw to slide forwards after it has closed between the two upper rows of teeth.
This mechanism allows the jaws to shear through
chitin
Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...
and bone.
Fossils indicate that the jaw mechanism began evolving at least 200 million years ago. The teeth are not replaced. As their teeth wear down, older tuatara have to switch to softer prey such as
earthworm
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...
s,
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e, and
slug
Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...
s, and eventually have to chew their food between smooth jaw bones.
It is a common misconception that tuatara lack teeth and instead have sharp projections on the jaw bone,
though histology shows that they have enamel and dentine with pulp cavities.
The brain of ''Sphenodon'' fills only half of the volume of its
endocranium
The endocranium in comparative anatomy is a part of the skull base in vertebrates and it represents the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy.
Structure
Structurally, t ...
.
This proportion has actually been used by paleontologists trying to estimate the volume of dinosaur brains based on fossils.
However, the proportion of the tuatara endocranium occupied by its brain may not be a very good guide to the same proportion in Mesozoic dinosaurs since modern birds are surviving dinosaurs but have brains which occupy a much greater relative volume in the endocranium.
Sensory organs
Eyes
The eyes can
focus
Focus, or its plural form foci may refer to:
Arts
* Focus or Focus Festival, former name of the Adelaide Fringe arts festival in South Australia Film
*''Focus'', a 1962 TV film starring James Whitmore
* ''Focus'' (2001 film), a 2001 film based ...
independently, and are specialised with three types of photoreceptive cells, all with fine structural characteristics of retinal
cone cell
Cone cells, or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different wavelengths, and the combination of their responses is responsible for color vision. Cone ...
s used for both day and night vision, and a ''
tapetum lucidum
The ''tapetum lucidum'' ( ; ; ) is a layer of tissue in the eye of many vertebrates and some other animals. Lying immediately behind the retina, it is a retroreflector. It reflects visible light back through the retina, increasing the light a ...
'' which reflects onto the retina to enhance vision in the dark. There is also a third eyelid on each eye, the
nictitating membrane
The nictitating membrane (from Latin '' nictare'', to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision. All ...
. Five visual
opsin
Animal opsins are G-protein-coupled receptors and a group of proteins made light-sensitive via a chromophore, typically retinal. When bound to retinal, opsins become Retinylidene proteins, but are usually still called opsins regardless. Most pro ...
genes are present, suggesting good
colour vision
Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different wavelengths (i.e., different spectral power distributions) independently of light intensity. Color perception is a part of t ...
, possibly even at low light levels.
Parietal eye (third eye)
The tuatara has a third eye on the top of its head called the
parietal eye
A parietal eye, also known as a third eye or pineal eye, is a part of the epithalamus present in some vertebrates. The eye is located at the top of the head, is photoreceptive and is associated with the pineal gland, regulating circadian rhythm ...
. It has its own lens, a parietal plug which resembles a
cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power ...
,
retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
with rod-like structures, and degenerated nerve connection to the brain. The parietal eye is visible only in hatchlings, which have a translucent patch at the top centre of the skull. After four to six months, it becomes covered with opaque scales and pigment.
Its use is unknown, but it may be useful in absorbing
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
rays to produce
vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
,
as well as to determine light/dark cycles, and help with
thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
.
Of all extant tetrapods, the parietal eye is most pronounced in the tuatara. It is part of the pineal complex, another part of which is the
pineal gland
The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep, sleep patterns in both circadian rhythm, circ ...
, which in tuatara secretes melatonin at night.
Some
salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten ...
s have been shown to use their pineal bodies to perceive polarised light, and thus determine the position of the sun, even under cloud cover, aiding
navigation
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...
.
Hearing
Together with
turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
s, the tuatara has the most primitive hearing organs among the amniotes. There is no
eardrum
In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear
The outer ear, external ear, or auris externa is the extern ...
and no earhole,
they lack a tympanum, and the
middle ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear).
The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...
cavity is filled with loose tissue, mostly
adipose (fatty) tissue. The
stapes
The ''stapes'' or stirrup is a bone in the middle ear of humans and other animals which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the foot ...
comes into contact with the
quadrate (which is immovable), as well as the
hyoid
The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra. ...
and
squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone.
In most tetrapods, the squamosal and quadratojugal The quadratojugal is a skull bone present in many vertebrates, including ...
. The
hair cell
Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. ...
s are unspecialised, innervated by both
afferent and
efferent nerve
Efferent nerve fibers refer to axonal projections that ''exit'' a particular region; as opposed to afferent projections that ''arrive'' at the region. These terms have a slightly different meaning in the context of the peripheral nervous syste ...
fibres, and respond only to low frequencies. Though the hearing organs are poorly developed and primitive with no visible external ears, they can still show a frequency response from 100 to 800
Hz, with peak sensitivity of 40
dB at 200 Hz.
Odorant receptors
Animals that depend on the sense of smell to capture prey, escape from predators or simply interact with the environment they inhabit, usually have many odorant receptors. These receptors are expressed in the dendritic membranes of the neurons for the detection of odours. The tuatara has several hundred receptors, around 472, a number more similar to what birds have than to the large number of receptors that turtles and crocodiles may have.
Spine and ribs
The tuatara
spine
Spine or spinal may refer to:
Science Biology
* Vertebral column, also known as the backbone
* Dendritic spine, a small membranous protrusion from a neuron's dendrite
* Thorns, spines, and prickles, needle-like structures in plants
* Spine (zoolog ...
is made up of hourglass-shaped
amphicoelous vertebrae, concave both before and behind.
This is the usual condition of fish vertebrae and some amphibians, but is unique to tuatara within the amniotes. The vertebral bodies have a tiny hole through which a constricted remnant of the notochord passes; this was typical in early fossil reptiles, but lost in most other amniotes.
The tuatara has
gastralia
Gastralia (singular gastralium) are dermal bones found in the ventral body wall of modern crocodilians and tuatara, and many prehistoric tetrapods. They are found between the sternum and pelvis, and do not articulate with the vertebrae. In these ...
, rib-like bones also called gastric or abdominal ribs, the presumed ancestral trait of diapsids. They are found in some
lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s, where they are mostly made of cartilage, as well as crocodiles and the tuatara, and are not attached to the spine or thoracic ribs. The true ribs are small projections, with small, hooked bones, called uncinate processes, found on the rear of each rib.
This feature is also present in birds. The tuatara is the only living
tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
with well-developed gastralia and uncinate processes.
In the early tetrapods, the gastralia and ribs with uncinate processes, together with bony elements such as bony plates in the skin (osteoderms) and
clavicle
The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...
s (collar bone), would have formed a sort of exoskeleton around the body, protecting the belly and helping to hold in the guts and inner organs. These anatomical details most likely evolved from structures involved in locomotion even before the vertebrates ventured onto land. The gastralia may have been involved in the breathing process in early amphibians and reptiles. The pelvis and shoulder girdles are arranged differently from those of lizards, as is the case with other parts of the internal anatomy and its scales.
Tail and back
The spiny plates on the back and tail of the tuatara resemble those of a crocodile more than a lizard, but the tuatara shares with lizards the ability to break off its tail when caught by a predator, and then regenerate it. The regrowth takes a long time and differs from that of lizards. Well illustrated reports on tail regeneration in tuatara have been published by Alibardi & Meyer-Rochow.
Age determination
Currently, there are two means of determining the age of tuatara. Using microscopic inspection, hematoxylinophilic rings can be identified and counted in both the phalanges and the femur. Phalangeal hematoxylinophilic rings can be used for tuatara up to ages 12–14 years, as they cease to form around this age. Femoral rings follow a similar trend, however they are useful for tuatara up to ages 25–35 years. Around that age, femoral rings cease to form. Further research on age determination methods for tuatara is required, as tuatara have lifespans much longer than 35 years (ages up to 60
[ are common, and captive tuatara have lived to over 100 years][). One possibility could be via examination of tooth wear and tear, as tuatara have fused sets of teeth.
]
Taxonomy and evolution
Tuatara, along with other now-extinct members of the order Sphenodontia, belong to the superorder Lepidosauria
The Lepidosauria (, from Greek meaning ''scaled lizards'') is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes snakes, lizards, and amphisbaenians. Squamata contains over 9,000 species, m ...
, the only surviving taxon within Lepidosauromorpha
Lepidosauromorpha (in PhyloCode known as ''Pan-Lepidosauria'') is a group of reptiles comprising all diapsids closer to lizards than to archosaurs (which include crocodiles and birds). The only living sub-group is the Lepidosauria, which contains ...
. Squamates and tuatara both show caudal autotomy
Autotomy (from the Greek ''auto-'', "self-" and ''tome'', "severing", αὐτοτομία) or self-amputation, is the behaviour whereby an animal sheds or discards one or more of its own appendages, usually as a self-defense mechanism to elude a ...
(loss of the tail-tip when threatened), and have transverse cloacal slits. The origin of the tuatara probably lies close to the split between the Lepidosauromorpha and the Archosauromorpha
Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, liza ...
. Though tuatara resemble lizards, the similarity is superficial, because the family has several characteristics unique among reptile
Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...
s. The typical lizard shape is very common for the early amniotes
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are distingu ...
; the oldest known fossil of a reptile, the ''Hylonomus
''Hylonomus'' (; ''hylo-'' "forest" + ''nomos'' "dweller") is an extinct genus of reptile that lived 312 million years ago during the Late Carboniferous period.
It is the earliest unquestionable reptile (''Westlothiana'' is older, but in fact it ...
'', resembles a modern lizard.
Tuatara were originally classified as lizards in 1831 when the British Museum
The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum ...
received a skull. The genus remained misclassified until 1867, when A.C.L.G. Günther of the British Museum noted features similar to birds, turtles, and crocodiles. He proposed the order Rhynchocephalia (meaning "beak head") for the tuatara and its fossil relatives.
At one point many disparately related species were incorrectly referred to the Rhynchocephalia, resulting in what taxonomists call a "wastebasket taxon
Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...
". Williston proposed the Sphenodontia to include only tuatara and their closest fossil relatives in 1925. However, Rhynchocephalia is the older name and in widespread use today. ''Sphenodon'' is derived from the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
for "wedge" (σφήν, σφηνός/''sphenos'') and "tooth" (ὀδούς, ὀδόντος/''odontos'').
Tuatara have been referred to as living fossil
A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossi ...
s, due to a perception that they retain many basal characteristics from around the time of the squamate–rhynchocephalian split (240 MYA). Morphometric
Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...
analyses of variation in jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth and serv ...
morphology among tuatara and extinct rhynchocephalian relatives have been argued to demonstrate morphological conservatism and support for the classification of tuatara as a 'living fossil', but the reliability of these results has been criticised and debated. Paleontological
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (geology), epoch (roughly 11,700 years before present). It includes t ...
research on rhynchocephalians indicates that the group has undergone a variety of changes throughout the Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...
,[ and the rate of ]molecular evolution
Molecular evolution is the process of change in the sequence composition of cellular molecules such as DNA, RNA, and proteins across generations. The field of molecular evolution uses principles of evolutionary biology and population genetics ...
for tuatara has been estimated to be among the fastest of any animal yet examined. However, a 2020 analysis of the tuatara genome reached the opposite conclusion: That its rate of DNA substitutions per site is actually lower than for any analysed squamate. Many of the niches occupied by lizards
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia althou ...
today were formerly held by rhynchocephalians. There was even a successful group of aquatic rhynchocephalians known as pleurosaurs, which differed markedly from living tuatara. Tuatara show cold-weather adaptations that allow them to thrive on the islands of New Zealand; these adaptations may be unique to tuatara since their sphenodontian ancestors lived in the much warmer climates of the Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...
. For instance, ''Palaeopleurosaurus
''Palaeopleurosaurus'' is an extinct genus of diapsid reptiles belonging to the group Sphenodontia.Dupret, V. (2004). The pleurosaurs: anatomy and phylogeny. ''Revue de Paléobiologie'', 9: 61-8/ref>
''Palaeopleurosaurus'' fossils were discov ...
'' appears to have had a much shorter lifespan compared to the modern tuatara. Ultimately most scientists consider the phrase 'living fossil' to be unhelpful and misleading.
A species of sphenodontine is known from the Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
Saint Bathans Fauna
The St Bathans fauna is found in the lower Bannockburn Formation of the Manuherikia Group of Central Otago, in the South Island of New Zealand. It comprises a suite of fossilised prehistoric animals from the late Early Miocene (Altonian) period, ...
. Whether it is referable to ''Sphenodon'' proper is not entirely clear, but is likely to be closely related to tuatara.[
]
Species
While there is currently considered to be only one living species of tuatara, two species were previously identified: ''Sphenodon punctatus'', or northern tuatara, and the much rarer ''Sphenodon guntheri'', or Brothers Island tuatara, which is confined to North Brother Island in Cook Strait
Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A H, ...
. The specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
''punctatus'' is Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
for "spotted", and ''guntheri'' refers to German
German(s) may refer to:
* Germany (of or related to)
**Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ger ...
-born British
British may refer to:
Peoples, culture, and language
* British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies.
** Britishness, the British identity and common culture
* British English, ...
herpetologist
Herpetology (from Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and rept ...
Albert Günther
Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive re ...
. A 2009 paper re-examined the genetic bases used to distinguish the two supposed species of tuatara, and concluded they only represent geographic variants, and only one species should be recognized. Consequently, the northern tuatara was re-classified as ''Sphenodon punctatus punctatus'' and the Brothers Island tuatara as ''Sphenodon punctatus guntheri''. Individuals from Brothers Island could also not be distinguished from other modern and fossil samples based on jaw morphology.
The Brothers Island tuatara has olive brown skin with yellowish patches, while the colour of the northern tuatara ranges from olive green through grey to dark pink or brick red, often mottled, and always with white spots. In addition, the Brothers Island tuatara is considerably smaller. An extinct species of ''Sphenodon'' was identified in November 1885 by William Colenso, who was sent an incomplete subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
specimen from a local coal mine. Colenso named the new species ''S. diversum''.
Genomic characteristics
Long interspersed nuclear elements (LINEs)
The most abundant LINE element
In geometry, the line element or length element can be informally thought of as a line segment associated with an infinitesimal displacement vector in a metric space. The length of the line element, which may be thought of as a differential arc l ...
in the tuatara is L2 (10%). Most of them are interspersed and can remain active. The longest L2 element found is 4 kb long and 83% of the sequences had ORF2p completely intact. The CR1 element is the second most repeated (4%). Phylogenetic analysis shows that these sequences are very different from those found in other nearby species such as lizards. Finally, less than 1% are elements belonging to L1, a low percentage since these elements tend to predominate in placental mammals.
Usually, the predominant LINE elements are the CR1, contrary to what has been seen in the tuatara. This suggests that perhaps the genome repeats of sauropsids were very different compared to mammals, birds and lizards.
Major histocompatibility complex elements (MHCs)
The genes of the major histocompatibility complex
The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are calle ...
(MHC) are known to play roles in disease resistance, mate choice
Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior.Bateson, Paul Patrick Gordon. "Mate Choice." Mate Choic ...
, and kin recognition in various vertebrate species. Among known vertebrate genomes, MHCs are considered one of the most polymorphic. In the tuatara, 56 MHC genes have been identified; some of which are similar to MHCs of amphibians and mammals. Most MHCs that were annotated in the tuatara genome are highly conserved, however there is large genomic rearrangement observed in distant lepidosauria
The Lepidosauria (, from Greek meaning ''scaled lizards'') is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes snakes, lizards, and amphisbaenians. Squamata contains over 9,000 species, m ...
lineages.
Short interspersed nuclear elements (SINEs)
Many of the elements that have been analyzed are present in all amniote
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are disti ...
s, most are mammalian interspersed repeats or MIR, specifically the diversity of MIR subfamilies is the highest that has been studied so far in an amniote. 16 families of SINEs
Sines () is a city and a municipality in Portugal. The municipality, divided into two parishes, has around 14,214 inhabitants (2021) in an area of . Sines holds an important oil refinery and several petrochemical industries. It is also a popular ...
that were recently active have also been identified.
DNA transposon
The tuatara has 24 unique families of DNA transposon DNA transposons are DNA sequences, sometimes referred to "jumping genes", that can move and integrate to different locations within the genome. They are class II transposable elements (TEs) that move through a DNA intermediate, as opposed to class ...
s, and at least 30 subfamilies were recently active. This diversity is greater than what has been found in other amniotes and in addition, thousands of identical copies of these transposons have been analyzed, suggesting to researchers that there is recent activity.
LTR retrotransposons
Around 7,500 LTRs have been identified, including 450 endogenous retrovirus
Endogenous retroviruses (ERVs) are endogenous viral elements in the genome that closely resemble and can be derived from retroviruses. They are abundant in the genomes of jawed vertebrates, and they comprise up to 5–8% of the human genome (l ...
es (ERVs). Studies in other Sauropsida
Sauropsida ("lizard faces") is a clade of amniotes, broadly equivalent to the class Reptilia. Sauropsida is the sister taxon to Synapsida, the other clade of amniotes which includes mammals as its only modern representatives. Although early syna ...
have recognized a similar number but nevertheless, in the genome of the tuatara it has been found a very old clade of retrovirus known as Spumavirus
''Spumaretrovirinae'', commonly called spumaviruses (, Latin for "foam") or foamyviruses, is a subfamily of the ''Retroviridae'' family. ICTVMaster Species List 2018a v1MSL including all taxa updates since the 2017 release. Fall 2018 (MSL #33) Sp ...
.
Non-coding RNA
More than 8,000 non-coding RNA
A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non-c ...
-related elements have been identified in the tuatara genome, of which the vast majority, about 6,900, are derived from recently active transposable elements. The rest are related to ribosomal, spliceosomal and signal recognition particle RNA
The signal recognition particle RNA, (also known as 7SL, 6S or 4.5S RNA) is part of the signal recognition particle (SRP) ribonucleoprotein complex. SRP recognizes the signal peptide and binds to the ribosome, halting protein synthesis. Signal re ...
.
Mitochondrial genome
The mitochondrial genome
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...
of the genus Sphenodon is approximately 18,000 bp in size and consists of 13 protein-coding genes, 2 ribosomal RNA
Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal ...
and 22 transfer RNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ac ...
genes.
DNA methylation
DNA methylation
DNA methylation is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts t ...
is a very common modification in animals and the distribution of CpG site
The CpG sites or CG sites are regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide in the linear sequence of bases along its 5' → 3' direction. CpG sites occur with high frequency in genomic regions called CpG isl ...
s within genomes affects this methylation. Specifically, 81% of these CpG sites have been found to be methylated in the tuatara genome. Recent publications propose that this high level of methylation may be due to the amount of repeating elements that exist in the genome of this animal. This pattern is closer to what occurs in organisms such as zebrafish, about 78%, while in humans it is only 70%.
Behaviour
Adult tuatara are terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
and nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
reptiles, though they will often bask in the sun to warm their bodies. Hatchlings hide under logs and stones, and are diurnal, likely because adults are cannibalistic. Juveniles are typically active at night, but can be found active during the day. The juveniles' movement pattern is attributed to genetic hardwire of conspecifics for predator avoidance and thermal restrictions. Tuatara thrive in temperatures much lower than those tolerated by most reptiles, and hibernate
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
during winter. They remain active at temperatures as low as , while temperatures over are generally fatal. The optimal body temperature for the tuatara is from , the lowest of any reptile. The body temperature of tuatara is lower than that of other reptiles, ranging from over a day, whereas most reptiles have body temperatures around . The low body temperature results in a slower metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
.
Burrowing seabirds such as petrel
Petrels are tube-nosed seabirds in the bird order Procellariiformes.
Description
The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross f ...
s, prions
Prions are misfolded proteins that have the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals. It i ...
, and shearwater
Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwa ...
s share the tuatara's island habitat during the birds' nesting seasons. The tuatara use the bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s' burrows for shelter when available, or dig their own. The seabirds' guano
Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...
helps to maintain invertebrate populations on which tuatara predominantly prey; including beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s, crickets
Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...
, and spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s. Their diets also consist of frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
s, lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s, and bird's eggs and chicks. The diet of the tuatara varies seasonally and they mainly only consume fairy prions and their eggs in the summer. In total darkness no feeding attempt whatsoever was observed and the lowest light intensity at which an attempt to snatch a beetle was observed occurred under 0.0125 lux
The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). It is equal to one lumen per square metre. In photometry, this is used as a measure of the intensity, as perceived by the ...
. The eggs and young of seabirds that are seasonally available as food for tuatara may provide beneficial fatty acids.[ Tuatara of both sexes defend territories, and will threaten and eventually bite intruders. The bite can cause serious injury. Tuatara will bite when approached, and will not let go easily.]
Reproduction
Tuatara reproduce very slowly, taking 10 to 20 years to reach sexual maturity. Though their reproduction rate is slow, tuatara have the fastest swimming sperm by two to four times compared to all reptiles studied earlier. Mating occurs in midsummer; females mate and lay egg
An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s once every four years. During courtship, a male makes his skin darker, raises his crests, and parades toward the female. He slowly walks in circles around the female with stiffened legs. The female will either submit, and allow the male to mount her, or retreat to her burrow. Males do not have a penis; they have rudimentary hemipenes
A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamata, squamates (snakes, lizards and amphisbaenia, worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erecti ...
; meaning that intromittent organ
An intromittent organ is any external organ of a male organism that is specialized to deliver sperm during copulation. Intromittent organs are found most often in terrestrial species, as most non-mammalian aquatic species fertilize their eggs e ...
s are used to deliver sperm to the female during copulation. They reproduce by the male lifting the tail of the female and placing his vent
Vent or vents may refer to:
Science and technology Biology
*Vent, the cloaca region of an animal
*Vent DNA polymerase, a thermostable DNA polymerase
Geology
*Hydrothermal vent, a fissure in a planet's surface from which geothermally heated water ...
over hers. This process is sometimes referred to as a "cloacal kiss". The sperm
Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...
is then transferred into the female, much like the mating process in birds. Along with birds, the tuatara is one of the few members of amniota
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are distingu ...
to have lost the ancestral penis.
Tuatara eggs have a soft, parchment-like 0.2 mm thick shell that consists of calcite crystals embedded in a matrix of fibrous layers. It takes the females between one and three years to provide eggs with yolk, and up to seven months to form the shell. It then takes between 12 and 15 months from copulation to hatching. This means reproduction occurs at two- to five-year intervals, the slowest in any reptile.[ Wild tuatara are known to be still reproducing at about 60 years of age; "Henry", a male tuatara at Southland Museum in ]Invercargill
Invercargill ( , mi, Waihōpai is the southernmost and westernmost city in New Zealand, and one of the southernmost cities in the world. It is the commercial centre of the Southland region. The city lies in the heart of the wide expanse of t ...
, New Zealand, became a father (possibly for the first time) on 23 January 2009, at age 111, with an 80 year-old female.[
The sex of a hatchling depends on the temperature of the egg, with warmer eggs tending to produce male tuatara, and cooler eggs producing females. Eggs incubated at have an equal chance of being male or female. However, at , 80% are likely to be males, and at , 80% are likely to be females; at all hatchlings will be females.] Some evidence indicates sex determination in tuatara is determined by both genetic and environmental factors.
Tuatara probably have the slowest growth rates of any reptile, continuing to grow larger for the first 35 years of their lives. The average lifespan is about 60 years, but they can live to be well over 100 years old; tuatara could be the reptile with the second longest lifespan after tortoises. Some experts believe that captive tuatara could live as long as 200 years. This may be related to genes that offer protection against reactive oxygen species. The tuatara genome has 26 genes that encode selenoprotein In molecular biology a selenoprotein is any protein that includes a selenocysteine (Sec, U, Se-Cys) amino acid residue. Among functionally characterized selenoproteins are five glutathione peroxidases (GPX) and three thioredoxin reductases, (TrxR/TX ...
s and 4 selenocysteine
Selenocysteine (symbol Sec or U, in older publications also as Se-Cys) is the 21st proteinogenic amino acid. Selenoproteins contain selenocysteine residues. Selenocysteine is an analogue of the more common cysteine with selenium in place of the s ...
-specific tRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ac ...
genes. In humans, selenoproteins have a function of antioxidation, redox regulation and synthesis of thyroid hormones. It is not fully demonstrated, but these genes may be related to the longevity of this animal or may have emerged as a result of the low levels of selenium and other trace elements in the New Zealand terrestrial systems.
Conservation
Tuatara are absolutely protected under New Zealand's Wildlife Act 1953
Wildlife Act 1953 is an Act of Parliament in New Zealand. Under the act, the majority of native New Zealand vertebrate species are protected by law, and may not be hunted, killed, eaten or possessed. Violations may be punished with fines of up to ...
. The species is also listed under Appendix I of the Convention on International Trade in Endangered Species
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
(CITES) meaning commercial international trade in wild sourced specimens is prohibited and all other international trade (including in parts and derivatives) is regulated by the CITES permit system.
Distribution and threats
Tuatara were once widespread on New Zealand's main North and South Islands, where subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
remains have been found in sand dunes, caves, and Māori midden
A midden (also kitchen midden or shell heap) is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, mollusc shells, potsherds, lithics (especially debitage), and other artifacts and ecofact ...
s. Wiped out from the main islands before European settlement, they were long confined to 32 offshore islands free of mammals. The islands are difficult to get to, and are colonised by few animal species, indicating that some animals absent from these islands may have caused tuatara to disappear from the mainland. However, ''kiore'' (Polynesian rat
The Polynesian rat, Pacific rat or little rat (''Rattus exulans''), known to the Māori as ''kiore'', is the third most widespread species of rat in the world behind the brown rat and black rat. The Polynesian rat originated in Southeast Asia, a ...
s) had recently become established on several of the islands, and tuatara were persisting, but not breeding, on these islands. Additionally, tuatara were much rarer on the rat-inhabited islands.[ Prior to conservation work, 25% of the distinct tuatara populations had become extinct in the past century.]
The recent discovery of a tuatara hatchling on the mainland indicates that attempts to re-establish a breeding population on the New Zealand mainland have had some success. The total population of tuatara is estimated to be between 60,000 and 100,000.
Climate Change
Tuataras have temperature-dependent sex determination meaning that the temperature of the egg determines the sex of the animal. For tuataras, lower egg incubation temperatures lead to males while higher temperatures lead to females. Since global temperatures are increasing faster than ever, researchers are worried that climate change is skewing the male to female ratio of tuataras and that in a few decades tuatara offspring populations will be all male.
Eradication of rats
Tuatara were removed from Stanley
Stanley may refer to:
Arts and entertainment
Film and television
* ''Stanley'' (1972 film), an American horror film
* ''Stanley'' (1984 film), an Australian comedy
* ''Stanley'' (1999 film), an animated short
* ''Stanley'' (1956 TV series) ...
, Red Mercury
Red mercury is purportedly a substance of uncertain composition used in the creation of nuclear weapons, as well as other weapons systems. Because of the great secrecy surrounding the development and manufacturing of nuclear weapons, there is no ...
and Cuvier Island
Cuvier Island is a small uninhabited island off the east coast of the North Island of New Zealand. It lies on the seaward end of the Colville Channel, north of the Mercury Islands and approximately south-east of Great Barrier Island. The island ...
s in 1990 and 1991, and maintained in captivity to allow Polynesian rats to be eradicated on those islands. All three populations bred in captivity, and after successful eradication of the rats, all individuals, including the new juveniles, were returned to their islands of origin. In the 1991–92 season, Little Barrier Island
Little Barrier Island, or Hauturu in Māori language (the official Māori title is ''Te Hauturu-o-Toi''), lies off the northeastern coast of New Zealand's North Island. Located to the north of Auckland, the island is separated from the mainla ...
was found to hold only eight tuatara, which were taken into ''in situ
''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...
'' captivity, where females produced 42 eggs, which were incubated at Victoria University. The resulting offspring were subsequently held in an enclosure on the island, then released into the wild in 2006 after rats were eradicated there.
In the Hen and Chicken Islands
The Hen and Chicken Islands (usually known collectively as the ''Hen and Chickens'') lie to the east of the North Auckland Peninsula off the coast of northern New Zealand. They lie east of Bream Head and south-east of Whangarei with a total ...
, Polynesian rats were eradicated on Whatupuke in 1993, Lady Alice Island in 1994, and Coppermine Island in 1997. Following this program, juveniles have once again been seen on the latter three islands. In contrast, rats persist on Hen Island of the same group, and no juvenile tuatara have been seen there as of 2001. In the Alderman Islands, Middle Chain Island holds no tuatara, but it is considered possible for rats to swim between Middle Chain and other islands that do hold tuatara, and the rats were eradicated in 1992 to prevent this.[ Another rodent eradication was carried out on the Rangitoto Islands east of ]D'Urville Island
D'Urville Island (), Māori language, Māori name ' ('red heavens look to the south'), is an island in the Marlborough Sounds along the northern coast of the South Island of New Zealand. It was named after the France, French List of explorers, ...
, to prepare for the release of 432 Cook Strait tuatara juveniles in 2004, which were being raised at Victoria University as of 2001.
Brothers Island tuatara
''Sphenodon punctatus guntheri'' is present naturally on one small island with a population of approximately 400. In 1995, 50 juvenile and 18 adult Brothers Island tuatara were moved to Titi Island in Cook Strait
Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A H, ...
, and their establishment monitored. Two years later, more than half of the animals had been seen again and of those all but one had gained weight. In 1998, 34 juveniles from captive breeding and 20 wild-caught adults were similarly transferred to Matiu/Somes Island
Matiu / Somes Island is the largest of three islands in the northern half of Wellington Harbour, New Zealand. It is the former site of military and quarantine internments, as well as animal quarantine until 1995. Since 1995 it has been designat ...
, a more publicly accessible location in Wellington Harbour. The captive juveniles were from induced layings from wild females.
In late October 2007, 50 tuatara collected as eggs from North Brother Island and hatched at Victoria University were being released onto Long Island
Long Island is a densely populated island in the southeastern region of the U.S. state of New York (state), New York, part of the New York metropolitan area. With over 8 million people, Long Island is the most populous island in the United Sta ...
in the outer Marlborough Sounds
The Marlborough Sounds are an extensive network of sea-drowned valleys at the northern end of the South Island of New Zealand. The Marlborough Sounds were created by a combination of land subsidence and rising sea levels. According to Māori m ...
. The animals had been cared for at Wellington Zoo for the previous five years and had been kept in secret in a specially built enclosure at the zoo, off display.
There is another out of country population of Brothers Island tuatara that was given to the San Diego Zoological Society and is housed off-display at the San Diego Zoo
The San Diego Zoo is a zoo in Balboa Park, San Diego, California, housing 4000 animals of more than 650 species and subspecies on of Balboa Park leased from the City of San Diego. Its parent organization, San Diego Zoo Wildlife Alliance, is a p ...
facility in Balboa. No successful reproductive efforts have been reported yet.
Northern tuatara
''S. punctatus punctatus'' naturally occurs on 29 islands, and its population is estimated to be over 60,000 individuals.[ In 1996, 32 adult northern tuatara were moved from Moutoki Island to Moutohora. The carrying capacity of Moutohora is estimated at 8,500 individuals, and the island could allow public viewing of wild tuatara.][ In 2003, 60 northern tuatara were introduced to ]Tiritiri Matangi Island
Tiritiri Matangi Island is located in the Hauraki Gulf of New Zealand, east of the Whangaparaoa Peninsula in the North Island and north east of Auckland. The island is an open nature reserve managed by the Supporters of Tiritiri Matangi Incorpo ...
from Middle Island in the Mercury group
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Mercury ...
. They are occasionally seen sunbathing by visitors to the island. A mainland release of ''S.p. punctatus'' occurred in 2005 in the heavily fenced and monitored Karori Sanctuary. The second mainland release took place in October 2007, when a further 130 were transferred from Stephens Island to the Karori Sanctuary. In early 2009, the first recorded wild-born offspring were observed.
Captive breeding
The first successful breeding of tuatara in captivity is believed to have achieved by Sir Algernon Thomas
Sir Algernon Phillips Withiel Thomas (3 June 1857 – 28 December 1937) was a New Zealand university professor, geologist, biologist and educationalist. He was born in Birkenhead, Cheshire, England in 1857 and died in Auckland, New Zealand in 19 ...
at either his University offices or residence in Symonds Street in the late 1880s or his new home, Trewithiel, in Mount Eden in the early 1890s.
Several tuatara breeding programmes are active in New Zealand. Southland Museum and Art Gallery in Invercargill
Invercargill ( , mi, Waihōpai is the southernmost and westernmost city in New Zealand, and one of the southernmost cities in the world. It is the commercial centre of the Southland region. The city lies in the heart of the wide expanse of t ...
was the first institution to have a tuatara breeding programme; starting in 1986 they bred ''S. punctatus'' and have focused on ''S. guntheri'' more recently.
Hamilton Zoo
Hamilton Zoo ( mi, Rawhi Whakaaturanga o Kirikiriroa) is the main zoological garden of Hamilton, New Zealand. Covering , it is situated on Brymer Road in the Hamilton suburb of Rotokauri, on the outskirts of the metropolitan area towards the no ...
, Auckland Zoo
Auckland Zoo is a zoological garden in Auckland, New Zealand, situated next to Western Springs Park not far from Auckland's central business district. It is run by the Auckland Council with the Zoological Society of Auckland as a supporting ...
and Wellington Zoo
Wellington Zoo is a zoo in the green belt of Wellington, New Zealand.
History
Wellington Zoo was opened in 1906 by the late Prime Minister Richard Seddon after he was given a young lion – later named King Dick – by the Bostock and Wombwe ...
also breed tuatara for release into the wild. At Auckland Zoo in the 1990s it was discovered that tuatara have temperature-dependent sex determination Temperature-dependent sex determination (TSD) is a type of environmental sex determination in which the temperatures experienced during embryonic/larval development determine the sex of the offspring. It is only observed in reptiles and teleost fish ...
.
The Victoria University of Wellington
Victoria University of Wellington ( mi, Te Herenga Waka) is a university in Wellington, New Zealand. It was established in 1897 by Act of Parliament, and was a constituent college of the University of New Zealand.
The university is well know ...
maintains a research programme into the captive breeding of tuatara, and the Pukaha / Mount Bruce National Wildlife Centre
Pūkaha / Mount Bruce National Wildlife Centre is a captive breeding facility and visitor centre located in a protected forest area on State Highway 2 in New Zealand's Tararua district.
Location
Pukaha / Mount Bruce National Wildlife Centre is ...
keeps a pair and a juvenile.
The WildNZ Trust has a tuatara breeding enclosure at Ruawai
Ruawai is a small town located 30 km south of Dargaville in Northland, New Zealand.
The name literally translated from Maori means 'two waters' referring to the nearby Northern Wairoa River and Kaipara Harbour. The township primarily serv ...
. One notable captive breeding success story took place in January 2009, when all 11 eggs belonging to 110 year-old tuatara Henry and 80 year-old tuatara Mildred hatched. This story is especially remarkable as Henry required surgery to remove a cancerous tumour in order to successfully breed.
In January 2016, Chester Zoo
Chester Zoo is a zoo at Upton-by-Chester, Cheshire, England. Chester Zoo was opened in 1931 by George Mottershead and his family. It is one of the UK's largest zoos at . The zoo has a total land holding of approximately .
Chester Zoo is operate ...
, England, announced that they succeeded in breeding the tuatara in captivity for the first time outside its homeland.
Cultural significance
Tuatara feature in a number of indigenous legends, and are held as ''ariki'' (God forms). Tuatara are regarded as the messengers of Whiro
Whiro-te-tipua (Whiro, or Hiro in the Tuamotus) is the lord of darkness and embodiment of all evil in Māori mythology. He inhabits the underworld and is responsible for the ills of all people, a contrast to his brother and enemy Tāne.
Acco ...
, the god
In monotheism, monotheistic thought, God is usually viewed as the supreme being, creator deity, creator, and principal object of Faith#Religious views, faith.Richard Swinburne, Swinburne, R.G. "God" in Ted Honderich, Honderich, Ted. (ed)''The Ox ...
of death and disaster, and Māori women are forbidden to eat them. Tuatara also indicate ''tapu'' (the borders of what is sacred and restricted), beyond which there is ''mana'', meaning there could be serious consequences if that boundary is crossed. Māori women would sometimes tattoo images of lizards, some of which may represent tuatara, near their genitals. Today, tuatara are regarded as a ''taonga
''Taonga'' or ''taoka'' (in South Island Māori) is a Maori-language word that refers to a treasured possession in Māori culture. It lacks a direct translation into English, making its use in the Treaty of Waitangi significant. The current d ...
'' (special treasure) along with being viewed as the kaitiaki (guardian) of knowledge.
The tuatara was featured on one side of the New Zealand five-cent coin, which was phased out in October 2006. ''Tuatara'' was also the name of the Journal of the Biological Society of Victoria University College and subsequently Victoria University of Wellington
Victoria University of Wellington ( mi, Te Herenga Waka) is a university in Wellington, New Zealand. It was established in 1897 by Act of Parliament, and was a constituent college of the University of New Zealand.
The university is well know ...
, published from 1947 until 1993. It has now been digitised by the New Zealand Electronic Text Centre
The New Zealand Electronic Text Collection (NZETC; mi, Te Pūhikotuhi o Aotearoa) is a freely accessible online archive of New Zealand and Pacific Islands texts and heritage materials that are held by the Victoria University of Wellington Library ...
, also at Victoria.
In popular culture
* A tuatara named "Tua" is prominently featured in the 2017 novel '' Turtles All the Way Down'' by John Green
John Michael Green (born August 24, 1977) is an American author, YouTube Content creation, content creator, podcaster, and philanthropist. His books have more than 50 million copies in print worldwide, including ''The Fault in Our Stars'' ( ...
.
* The tuatara was the inspiration for a DC Comics superhero, also with a third eye, called Tuatara
Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ...
, member of the Global Guardians
The Global Guardians is a team of DC Comics superheroes whose members hail from countries around the world. The concept originated in the ''Super Friends'' Saturday morning cartoon, which aired after the comics stories in ''Super Friends'' #7- ...
.
* There is a brand of New Zealand craft beer named after the Tuatara which particularly references the third eye in its advertising.
* The Tuatara hypercar, designed and manufactured by SSC North America
SSC North America (formerly Shelby SuperCars Inc.) is an American automobile manufacturer founded in 1999 by owner Jerod Shelby (no relation to car designer Carroll Shelby). The company is based in Richland, in the Tri-Cities, Washington and ...
in the Tri-Cities, Washington
The Tri-Cities are three closely linked cities ( Kennewick, Pasco, and Richland) at the confluence of the Yakima, Snake, and Columbia Rivers in the Columbia Basin of Eastern Washington. The cities border one another, making the Tri-Cities se ...
, is named after the reptile, noting its fast evolving DNA and "peaks on the back" as inspiration in the creation of the car.
* The Auckland Tuatara
The Auckland Tuatara is a professional baseball team in the Australian Baseball League based in Auckland, New Zealand. They are the only team from New Zealand to compete in the ABL, and one of two expansion teams that entered the league in the ...
, one of two expansion teams for the 2018–2019 Australian Baseball League
The Australian Baseball League (ABL) is a professional baseball league in Australia. The league is governed by the Australian Baseball Federation (ABF). It uses the same name as a now-defunct competition held during the 1990s, and though it sh ...
season, chose the tuatara name to celebrate the resilience of the ancient reptiles, and to raise awareness of New Zealand's commitment to species protection.
* Tuatara
Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ...
is a music band from Seattle named after the animal.
* Tuatara Day is 2 May to recognise the day that the tuatara was first recognised not to be a lizard.
* In the season one finale of Abbott Elementary
''Abbott Elementary'' is an American mockumentary sitcom television series created by Quinta Brunson for ABC. It stars Brunson as a second-grade teacher at Abbott Elementary, a fictional predominantly Black school in Philadelphia. The ensemble ...
an old tuatara named Duster is used to represent themes of aging and transition.
See also
* Tuataric acid
* Tuatara tick
References
Further reading
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External links
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{{Taxonbar, from=Q163283
Endemic fauna of New Zealand
Extant Late Pleistocene first appearances
Māori culture
Reptiles of New Zealand
Sphenodontia
Taxa named by John Edward Gray
Endemic reptiles of New Zealand