STAMP CREATURES-—VI Strange reptile and leather jacket

Press, Volume CXII, Issue 33077, 18 November 1972, Page 12

STAMP CREATURES-—VI Strange reptile and leather jacket

(By

ARTHUR W. PARROTT)

The only reptile figured on New Zealand postage stamps is the tuatara, the strangest and certainly the most interesting of all living reptiles.

Living reptiles of the world are divided into four principal groups or orders. The first includes the alligators and the crocodiles, the second the turtles and tortoises, the third the snakes and lizards, and the fourth includes only one living representative — the tuatara. This aristocrat, whose ancient lineage and conservative instincts are not found in any other animal living today, is well figured on the 1935, 8d stamps of New Zealand.

(Sphenodon punctatus) 1935, 8d: Definitive issue. The tuatura is not a lizard but the sole survivor of a group of primitive reptiles that flourished 200 million years ago, long before the dinosaurs reached their peak. It first became known to science when a skull was received in England in 1831, but it was 10 years later when specimens were brought to England by E. Dieffenbach, the author of “Travel in New Zealand,” published in 1843, that the unique features of this ancient animal became known, after being examined and described by John Greg, of the British Museum.

The peculiar features of the skeleton of the tuatara could only be matched with fossil remains, from the Triassic period of the world’s history, 195 to 170 million years ago. It was necessary to establish a separate order

of reptiles to include both the fossils of extinct forms and the sole living representative, the tuatara. This remarkable animal is therefore the only surviving member of the order of “Beak-heads,” known to science as the Rhynchocephalia. The name “Beakhead” comes from the spadeshaped teeth set in the bones of the jaw, which together form a kind of beak. The scientific name of the order is derived from two Greek words, “rhynchos” a snout, and “kephale” a head. The scientific name of the tuatara is Sphenodon punctatus. The first or generic name means "wedgetooth” and refers to the shape of the teeth, and the specific name, “punctatus,” comes from the Latin “punctum,” a spot or point, and refers to the dotted or spotted appearance of the body. The Maori name tuatara is said to refer to the crest of softish white spines on top of the head and along the back, and means “peaks on the back.”

The tuataras are very sluggish creatures with an extraordinary low rate of metabolism and growth. Their body temperature is lower than in any other reptile, about 52 degrees Fahrenheit compared with not less than 58 degrees in other living reptiles. Even when actively engaged hunting for food, the tuatara breathes only once in seven seconds, and while resting may go for as long as an hour without taking a breath.

They are mostly nocturnal in habits and their food consists mainly of various insects and their grubs, spiders and earthworms, and other small invertebrates that live in leaf-mould or in the soil. Another anatomical feature of interest is the presence of a pineal eye (the third eye) which is welldeveloped. If the top of the head of a tuatara is carefully examined, a small rosette of small scales will be seen with a transparent central scale. Beiow this transparent scale is an organ, structurally similar to an eye, having a lens and pigmented retina. Although some lizards also possess a similar pineal eye, the

tuatara differs in that the nerve of the pineal eye, has remained Well - developed, whereas in the lizards the nerve is degenerate. The tuatara reaches an over-all length of 24in and adult males may wiegh up to 21b. The females are smaller and seldom exceed lib in weight. Their average lifespan is not known, but they are supposed to live up to 100 years. They do not commence breeding until they have reached 20 years of age and after which they apparently continue to grow until they have reached about 50 years. Their breeding habits show some interesting features. The male has no copulatory organ, in contrast to other living reptiles, and mating is probably accomplished as in birds, by direct contact of the cloacas. Another remarkable thing about this unique animal is that pairing takes place during January, and the sperm is stored in the female’s body until the following spring when it is used to fertilise the eggs.

The eggs, a little over lin long, are oval and are almost entirely filled with yellow yolk, containing very little albumen. Instead of a hard shell the egg is covered with a parchment-like membrane. The size of the clutch varies from eight to 15 eggs, which are laid in loose soils, in a shallow depression 4in or sin deep, made by the female. After the eggs are laid they are carefully covered and concealed with grass or leaves. The eggs are laid during November, but do not hatch until December of the following year. At first the eggs develop rapidly during the summer, and by March are in an advanced stage, but during the winter months the development of the embryo is almost completely suspended, and development is not resumed until the following spring. Suspended development in embryos is rare in vertebrates and has only been recorded in another reptile, the European turtle. During the lattfer stages of development the embryo develops a patch of homy skin on the snout, that forms a sharp cutting edge used to make an incision in the egg-shell at the time of hatching.

This aristocrat of ancient lineage is not of today, but lives in an atmosphere of splendid isolation from all other living creatures. Today the tuatara is confined to about a score of small islands adjacent to the mainland of New Zealand. These islands, all small, form two groups, those off the north-east coast of the North Island between North Cape and East Cape and those in the Cook Strait area.

The presence of the tuatara in New Zealand may be accounted for by ancient land connections. Because of its isolation survival was possible, while relatives in other parts of the world have become extinct.

Much more could be written on this “living fossil,” a creature that stood still through the ages while the world rushed past him, losing the battle to compete with modem life in every country except New Zealand, where until recently he roamed the mainland. Since European settlement in this country, the tuatara has been banished to a few small offshore islands which are its last strongholds. His end is inevitable, but we must try to preserve those remaining, in every possible way, so that future generations of New Zealanders may look and wonder at this relic from bygone ages.

The leatherjackets comprise a very distinct family of fishes, the aluteridae, equipped with a single large spine on the back, placed immediately above the eyes, which can be locked in position by a second very small, rudimentary spine, situated close behind its base. The large spine which is serrated or toothed, can be locked in position when partially or fully erect. Ventral fins are absent, but there is usually a well-developed, usually distensible, pelvic flat, between the chin and the anal fin, that looks like a dewlap. Many members of this family are small fishes, rarely reaching a length of lOin, but the giant of the family found in tropical seas may attain a length of 30in. The rough leatherjacket has the dorsal spine strongly barbed, the dorsal and anal fins are similar in shape and size and each have 35 soft rays. The minute scales covering the body are furnished with sharp points which give the surface of the skin a roughened appearance, and if you lightly rub your finger over the body towards the head, it feels like fine sandpaper. The gill-slits, one on each side of the body, just in front of and above the base of the pectoral fins, are small, hardly equalling in length the diameter of the eye. The small mouth has six outer teeth in each jaw, admirably suited for nibbling marine growths from rocks, kelp ana other objects.

A diagram of the “trigger” mechanism of the dorsal spine in leatherjackets. The broken line represents the back of the fish. A: Fully erect B: Partly erect Q Depressed.

The body is yellowish brown with the back darker brown, the abdomen whitish, and there are irregular reddish or brownish markings on the sides of the body and head. The markings on the body vary considerably. Usually there is a brown stripe running from above the nostrils over the eye and extending along the body to the base of the tail-fin. The head usually has two or three, more or less distinct oblique stripes and there is a wide vertical band below the pectoral fin. The colour pattern is very variable and hardly any two individuals are identical.

The rough leatherjacket is a smaller fish than its relative, the smooth leatherjacket, and specimens over lOin in length are rarely captured. The average length would be between 6in and Sin.

The rough leatherjacket is a common fish in shallow waters close inshore and most frequently found amongst kelp, seaweed of various kinds, in harbours, estuaries and inlets in both the South and North Islands. The Maori knew it as kokiri, and it was extensively used as food. If the skin of the fish is removed before cooking, the flesh is said to be white, firm and tasty.

In New Zealand the leatherjackets have received a number of popular names, such as file fishes, and trigger fishes, but these names are more correctly used for related groups of fishes frequenting the warmer waters of the oceans, especially in tropical seas.