Centralian rough knob-tail gecko

About the species

Nephrurus amyae is a knob-tailed gecko and looks like no other gecko. The body is thick and compact, the head and eyes are large in proportion to the rest, and the tail is only 1-1.5 cm long and ends in a small ball, the knob. The gecko waves it when stalking prey. The skin is covered with pointed knobs, especially on the back and thighs, and feels like sandpaper.

The species was described as recently as 1994 by Couper and Gregson and is named after Couper's daughter, Amy. The type locality is Winnecke Goldfields north of Alice Springs. It reaches up to 13.5 cm from snout to vent and is the largest species in the genus. Adults weigh 40-65 g, and females are the largest, while males are noticeably smaller and lighter. The colour matches the sand and stones of the desert and ranges from cream through salmon to reddish brown.

In the terrarium it is hardy and calm, but does not like to be picked up. By day it wants to be left in peace and only comes out when the light is off. Then in return it hunts industriously, and it is a pleasure to follow it with a weak torch. If it is startled, it rises high on its legs, opens its mouth and hisses hoarsely, but it is completely harmless.

Care

The enclosure

The species lives on the ground, so floor area counts, while height is almost irrelevant. An adult needs at least 60 × 45 × 30 cm (length × width × height). A pair or a male with two females needs a floor of at least 60 × 60 cm or 80 × 40 cm, and larger is always better. Many breeders use plastic boxes in racks, but a furnished desert terrarium gives far more to look at.

The substrate should be sand, 2-3 cm deep in the dry part. Provide two or three hides per animal, for example cork bark, artificial rock caves or an upturned saucer. The gecko does not dig deep burrows itself, but gladly uses a hide that resembles a rock crevice. Place a closed humid hide at one end, for example a plastic box with an opening in the side and damp sand. It is used when shedding and later for egg-laying. The rest of the enclosure must be dry, and good ventilation openings prevent stagnant air.

Temperature

Keep 24-28 °C in the enclosure by day and a warm spot of 30-32 °C, for example with a heat mat under one end or a small halogen spot, so that the animal can choose for itself. At night the temperature may fall to 20-23 °C.

Even though it is a desert species, it spends the day in shade, and too much heat is dangerous. There must always be a cool end below 28 °C. Breeding animals need a cool winter rest, see the section on mating. Measure with a digital thermometer both at the warm spot and at the cool end, and control all heat with a thermostat.

Humidity and water

Humidity should be 30-50 %, and most of the enclosure must be dry. Mist lightly once or twice a week in the evening, so the gecko can lick droplets from glass and stones. Many animals never drink from a water bowl, but a shallow, stable bowl does no harm.

The most important thing is the humid hide, where the sand is kept slightly damp all year. Here the animal sheds its skin, and here the female lays her eggs. Change the sand if it begins to smell or go mouldy.

Lighting and UVB

The gecko is nocturnal and sees little of the light. Some breeders nevertheless use a weak UVB light all year round, because the animals seem more active and calcium metabolism is more secure, while others manage without it when the food provides vitamin D3. UVB is therefore optional, but a good offer.

Use a T5 tube for shade-dwelling animals (Ferguson zone 1), for example 5 %, over part of the enclosure, so there is always shade. Let the day length follow the seasons: about 14 hours in summer, 12 hours in spring and autumn and 8 hours in winter. At night it must be dark, without coloured night lights.

Feeding

The gecko is a greedy insectivore. Adults get live insects three times a week, preferably a varied selection of crickets, roaches, mealworms, superworms and silkworms. Large roaches are often the favourite. A meal is typically 4-6 adult crickets or 1-2 large roaches. Do not release too many insects at once, because it stresses the animal. Juveniles are fed five times a week.

Dust the insects lightly with calcium with vitamin D3, give a multivitamin once a week, and feed the insects greens before they are served. Females that have laid eggs may become thin and need extra food. The tail is the animal's fat store, and a plump tail and tail base show that the animal is doing well.

Behaviour and handling

The species is calm, but does not like being handled. Pick it up seldom and briefly, and sit low, because it is no climber and can fall. If you hold too hard, it struggles or barks. Never grab the tail.

Most keepers find that the animals live peacefully together, and experienced breeders have kept a male with two females for years without fights. Do not put two males together all the same. Watch for bites, weight loss and animals that hide all the time, and separate them if there is unrest. By day the gecko sleeps in its hide and is hard to spot before the light goes off.

Breeding

Sexual maturity and sexing

Males are smaller than females and have, like other knob-tailed geckos, a distinct bulge at the base of the tail, where the hemipenal pouches sit, and pores in front of the vent. The sex can be seen fairly early, but it requires a magnifying glass and an animal large enough for the details to be seen.

The animals become sexually mature at an age of 12-24 months and are fully grown after about 18 months. Females should be at least 18 months old and weigh 45 g or more before being put to breed, while males are mature at a smaller size. The figures are based on the experience of a few breeders.

Mating

The animals need to feel the seasons in order to breed regularly. A well-described method begins in November by lowering the temperature gradually over a few weeks. Feeding is then stopped, while the heat is kept for another week, so the gut can empty. Then the heat is switched off for a week, and the animals are moved to small, airy boxes with sand and hides at about 10 °C, for example in an unheated room. One half of the sand is kept slightly damp, so they do not dry out. After about six weeks they are moved back, the temperature is raised over a week, and feeding is resumed.

Mating most often takes place a few weeks after the winter rest. Many breeders have the best luck letting pairs and trios stay together all year. Make sure the male is not too pushy, and separate the animals if the female becomes stressed.

Egg-laying and clutches

A gravid female becomes distinctly thicker, and the large eggs can be seen through the belly skin about two weeks before laying. She almost always lays two eggs at a time, occasionally only one, and the eggs are large in proportion to her.

The number of clutches varies: some breeders get four to six per season, others seldom more than two. Give the female a closed plastic box with 7-8 cm of damp sand to lay in. If the box is transparent, you can see the eggs from below. If she lacks a suitable place, she may hold the eggs back, and that is dangerous. Give her plenty of insects and calcium throughout the season.

Incubation

Carefully move the eggs to a small box with damp substrate without turning them. Perlite mixed with water 1:1 by weight, for example 30 g perlite and 30 g water, works well. Mark the top. The eggs grow considerably along the way.

Keep a stable temperature of 27-29 °C in an incubator. At 27 °C the eggs hatch after about 90 days, and normally it takes 80-100 days. A few sources mention up to 120 days, so be patient, and do not discard eggs too early. Whether temperature determines sex has not been studied.

Rearing the young

The hatchlings are large at hatching in proportion to the adults, but no reliable weight figures have been published. Keep them separately in small boxes with sand, a hide and a small humid hide at the same temperature as the adults. That way you can be sure that each hatchling is eating and growing.

Offer small insects dusted with calcium five times a week. Growth is slow at first, and the hatchlings are only fully grown after about 18 months. They shed often, so the humid hide must always be there.

Health and common mistakes

The species is hardy, and most problems are caused by wrong humidity, wrong heat or deficiencies in the food. The typical mistakes are:

• Too little calcium and vitamin D3, especially in egg-laying females and juveniles. It causes soft bones and tremors.
• Retained shed on the toes and around the eyes if the animal lacks a humid hide.
• Egg-laying difficulties if the female does not have a suitable, damp place to lay. A female that sits strained with a distended belly without laying must go to a vet.
• Dehydration if the whole enclosure is bone dry.
• Poor condition after breeding. The female must have time to put on weight again.
• Sand swallowed with the prey. Feed in a shallow dish, and use fine, clean sand.

A healthy gecko is plump, especially in the tail and at the tail base, has clear eyes and is active at night. See a vet experienced with reptiles if it loses weight, does not eat for several weeks, develops swellings or seems limp.