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This species of Newt is of a fairly robust constitution, especially compared to other representatives of the genus. It reaches a size of about 16-18cm (with females often being larger than males). The head appears bulky, compressed super-inferiorly, is of a triangular shape and slightly longer than wide. The upper lip can develop considerably, especially in adult females, even completely covering the lower lip, but without further descending downwards. At the jugular level there is a throat fold, which clearly divides the head from the body. The fingers are 4 anteriorly and 5 posteriorly and appear short and stocky and poorly fused together. The tail is compressed laterally and has a different shape in the two sexes:
The males have a generally shorter tail, with a more blunt end than the females. In addition, during the breeding season it tends to be coloured in a more contrasting way with a red-orange line longitudinally to the lower margin, and a pattern that, especially starting from the medial third, shows spots of a brighter / pearly white often enriched by a background shade that is sometimes more clear.
The females have a considerably longer tail, with a more pointed end and with less developed upper / lower membranes.
The body is fairly slender and more rounded in the females, with a more or less cylindrical cross section and a median longitudinal depression at the rachidian level. The cloaca appears different in the two sexes, especially in the reproductive period. The male presents a large, round cloaca. The female on the other hand, has a slightly conical cloaca, “volcanic-like”, but less pronounced than other closely related species.
The animals from Semdinli, and from all over the Turkish area, have many more numerous, irregular and small spots, generally of a more yellowish color than white.
The third form, from Choman, is kind of hybrid between the first two. In all forms, however, the belly appears uniform red-orange or interrupted by some black spots (however these spots are never found at the level of the chinstrap).
The skin is warty and rough to the touch on the back and sides, especially in the terrestrial phase, where it always appears opaque, never shiny and / or taut. The belly, however, always remains smooth.
In this species the lungs are partially atrophic.
Due to its colour pattern, Neurergus crocatus can easily be confused with Neurergus derjugini, Neurergus strauchii and Neurergus barani. On the other hand, it is impossible to confuse it with Neurergus kaiseri, given its particular colouring, which differs considerably from that of the other species of the genus. Until relatively recent times, certain populations of N. derjugini and N. strauchii have been confused with N. crocatus also by herpetologists, which has created numerous and embarrassing misunderstandings. However, at a careful glance, the species appear remarkably different:
Neurergus strauchii and barani have a colour patter that can sometimes pose many difficulties in their differential diagnosis, especially for the populations of Neurergus crocatus found in Turkey (Semdinli morph). However, Neurergus strauchii and barani can be differentiated easily thanks to the more long and slender conformation of the body. The shape of the skull is decidedly more flattened and less triangular and with more protruding eyes. The belly is the most noticeable difference as it is black except for a single orange-reddish median sagittal line variably wide and irregular (but less than half of the maximum transverse diameter of the trunk). The throat is also totally black, with two thin red lines at the level of the mandibular arches. In the reproductive period they develop bluish-silvery reflections on the tail, especially the males, but sometimes also the females. Their spots tend to be small and circular, a bright yellow color and do not fade or increase in size with age (They can instead increase in number).
Neurergus derjugini is perhaps even more easily confused than Neurergus strauchii and barani. Whilst juveniles easily differ in the presence of orange spots (especially on the parotoid level), over time these will become yellow. The conformation of the body is unmistakable given that N. derjugini is much more similar to N. kaiseri, with: less robust morphology than N. crocatus, smaller and less triangular cranial conformation, and toes of the hind legs partially merged together. The spots are of a bright yellow color and tend to be irregular, non-circular, and can sometimes be very large or dense and small. The labial crests tend to be more developed than in N. crocatus. The belly is bright red-orange and more interspersed with black spots, especially in the chinstrap, unlike N. crocatus which instead always has a uniformly red-orange throat.
The typical locality for the species is Lake Urmia in Iran, from which it takes the name “Lake Urmia newt”. The species is actually present in a more or less circular area, about 120km in diameter, on the border between Iran, Iraq and Turkey. In Turkey it is found in the Turkish provinces of Hakkari, Beytussebap, Semdinli. In Iraq it is found in Aqrah, Barzan, Girbish, Tazhika, Choman instead. For a long time (over 150 years) it was believed to be extinct in Iran, but it was later found again in 2013 in the typical locality of the species, near Lake Urmia.
Throughout its distribution range it can be found at mountain altitudes, from 750mslm to 1550mslm, near small and medium-sized streams and creeks, which guarantee for most of the year a temperature below 17°C. Alternatively, they have also been found in pools fed by these streams and creeks. Aquatic vegetation is practically absent in both environments, while the riparian vegetation can be vary from nothing to only grasses or various species with medium-high stems.
Little is known about the lives of individuals of this species in the middle of winter and summer. Probably in these periods they shelter under rocks, tunnels and other shelters, where temperatures and humidity tend to remain more uniform.
Temperatures in the warm months can be very high, with virtually no rainfall. In fact, even in terrariums, the species proves resistant to high temperatures and low air humidity.
At present no subspecies are known, but given the vast and fragmented range, further studies will be necessary.
Care in Captivity:
In nature this species colonizes mountain streams, so it is best to aim to recreate these conditions. In principle, this species can be housed entirely in an aquatic environment for most of the year without any problems. However, it is recommended to keep them on the ground for a period of about 1-4 months a year, especially in the brumation-hibernation phase.
For 3-5 animals in the aquatic phase, a 60x30x30cm aquarium will be sufficient, preferably larger. The substrate must be made of fine/ultrafine size sand or alternatively it can easily be left bare. As decoration, it will be sufficient to put stones or rocks (flat slate/sandstone work excellently), stacked in different points of the tank to recreate hiding places and places suitable to lay eggs. Tiles, hollow bricks, roots, etc. are also suitable. Aquatic plants, on the other hand, can be avoided. If wanted, excellent choices could include various aquatic mosses, Riccia fluitans or Aegagropila sp., but as always without overdoing it. Their main purpose will be to further oxygenate the water.
The last fundamental part of the set-up will concern the filter. It is best to equip it with UV-C sterilizer and with this species it is in fact strongly recommended, given that for proper breeding it is necessary to guarantee excellent water quality, with very low organic load. A pump that guarantees a medium/strong current, especially on the surface, is also strongly recommended.
The water level can safely remain at a level of only 10-15cm.
Numerous shelters with rocks and bark must be ensured. However, for the terrestrial part, make sure that the substrate maintains a low degree of humidity.
In terms of temperature, although they can tolerate above 27°C, it is better to never exceed 24°C. For this reason it will be good to have a cooling system such as fans or air conditioners or, for those who could, move the animals to a cellar.
However, in winter animals should be kept at temperatures below 10°C, even better if they are close to 0°C, preferably in a terrestrial setup.
Once adapted to the new environment, the species can be quite voracious. They eat the foods typical of the keeping of caudates without problem, including earthworms, bloodworms, brine shrimps, dafnie, gammarus, waterlice, woodlice, tubifex, mealworms, waxworms, crickets, and cockroaches. In captivity, for convenience, the basis of the diet may be earthworms, however, it is recommended to move towards a diet consisting mainly of crustaceans and insects (especially with the genus Neurergus).
Although in optimal conditions they can enter the reproductive phase throughout the year (with frequent courtship and sporadic laying of eggs), to have a greater chance of reproductive success, some points must be respected during the cold season:
- Proper brumation and hibernation
- Separate males from females
- Keeping animals in a terrestrial phase
Even though quite significant spawning has occurred at temperatures up to 25°C with none of the above points respected, none of the eggs have reached even the first stages of development.
To have a good chance of reproducing, it is necessary to gradually lower the temperature to maximums of 20-21°C from early September and during this time, the animals must be fed abundantly to allow them to put on mass. After this phase, approximately mid-October, temperatures permitting, the animals should be placed outdoors in a place sheltered from the sun and bad weather for about 1 month/a month and a half. At this stage it is very important to have the animals on land and separate the sexes. Make sure you feed the animals sufficiently during this phase, however, ensure you significantly reduce the administration of food the last 5-7 days before entering hibernation. The hibernation phase involves keeping the animals at temperatures, if possible, constantly below 5°C, or in any case always below 10°C for a period of at least 1-2 months.
The keepers in colder regions and/or high altitudes will have an advantage and will therefore be able to leave the animals simply outside, in the place previously chosen for the brumation. Anyone else, on the other hand, will have to adopt other systems, such as a refrigerator. In this phase the animals will feed very little but they will never enter real fasting periods as long as the temperatures remain above 3°C. It is best to feed them without excess every 7-14 days, depending on the temperatures. During this period, care should be taken that there are no malaise phenomena or that the humidity does not drop too much.
After this phase, the animals will be brought back to gradually warmer temperatures, up to about 12-14°C for about 2 weeks, while at the same time you should start to feed them again. After this phase you can finally move the animals back in the water. Many breeders move the males first (about 2 weeks in advance) and then the females later to replicate natural behaviour. However, placing them all together does not seem to negatively affect breeding. To help with reproduction, a sex ratio shifted in favor of males is recommended (for example, to have a small group of 4 males to 2 females compared to a 2 males and 4 females). To encourage courtship and spawning it is recommended to make partial changes of about 10-30% of the water, at greater frequency than usual, even up to 3 times a week. This will try to mimic the conditions of melting snow, which in nature feeds the streams colonized by this species. Frequent partial changes with clean and possibly fresh water helps to mimic natural conditions better, ensuring a greater probability of reproductive success.
The first courtships will begin within minutes or sometimes hours after insertion back in water. Courtship of tail-fanning by males. In this species it manifests itself with a fairly rapid “wagging” of the terminal half of the tail, placed parallel to the rest of the body and in the direction of the female. The courtships can last hours, for many consecutive days and occur mainly at night, with the males in a frantic pursuit of the females.
Sometimes you can witness the same phenomenon, only a little more nuanced, even in females, especially if they are receptive. In this case, the male then lets himself be chased by the female for a short distance (a few tens of cm at most), maintaining the head-tail contact, swaying the tail this time in a snake-like way, up to a point where it stops, lifts the tail from the substrate and lays a spermatophore.
At that point the male still moves forward until it stops again to make the female’s cloaca coincide with the deposit point of the spermatophore and thus allowing the absorption and fertilization of the eggs.
Also very important in this phase is to feed the animals abundantly and maintain a water temperature of about 15-17°C.
Within a few days the females should begin to lay up to 250 eggs each, especially on the underside of the submerged rocks, but also directly on the filter, glass and other furnishings. To do this, the females will begin to inspect any sites suitable for egg laying, after which they will try to adhere to the surfaces most sheltered from the current, but still well oxygenated, to lay their eggs. This often results in an upside down position that can last up to tens of minutes. Sometimes eggs can also be laid on any aquatic plants. The eggs (and the adults in the reproductive phase) must be kept at a temperature of maximum 19°C. Higher temperatures will result in an immediate block in spawning.
Care of eggs:
The Neurergus crocatus eggs are quite large, and can even reach over 10mm in diameter with full embryonic development (taking into account the external gelatinous annex). Once identified, they will need to be moved to special trays. In this phase, great care must be taken not to damage them, which is not easy task given the considerable size of each egg and the tenacity of the colloidal peduncle that attaches them to the substrate.
Contrary to many other cases, here syringes are absolutely not recommended. It is much better to arm yourself with a little patience and use a stiletto/pin trying to gently detach the egg from the anchoring substrate and then collect it with a fine net or a spoon. Typically hatching takes a period of 14-28 days. Given the difficulty of the collection, microtraumas can be present in many cases. In this case the eggs will have to be monitored carefully. The length of the embryonic development period can lead to bacteria or mycotic superinfection, potentially compromising respiratory exchanges and leading to the death of the embryo. Therefore, daily partial water changes are strongly recommended, as well as the daily (gentle) moving of the eggs. The use of an aerator or aquatic plants is also recommended but not essential.
Care of larvae:
Unlike many other species, the larvae of Neurergus crocatus usually come out of the egg with the front legs already perfectly formed and the yolk sack largely reabsorbed. This means that they can start feeding immediately and voraciously on typical preys such as daphnia, ostracods, copepods and brine shrimps nauplii. In other cases, especially for earlier hatching, nutrition may begin after the classic 1-10 days, upon completion of organogenesis and complete reabsorption of the yolk sac.
Given the average size of 11-14mm at hatching, many larvae will also be able to immediately start preying on larger invertebrates such as diptera larvae, white worms and young ephemeropteran nymphs. As usual avoid odonate nymphs, nymphs of ditiscus, ostracods, some species of copepods and other potentially predatory species, as they are able to decimate the population of larvae in a short time.
The larvae are very voracious and for the whole duration of development they have a growth rate of 2-4mm per week, showing little intraspecific aggression and consequently very few episodes of cannibalism if fed sufficiently. Their appearance and behavior is typical of larvae that live in a stream environment. They are in fact flattened dorsoventrally and not very inclined to swimming, preferring instead to stop on the bottom or amassing under whatever refuge they find.
It is essential to scrupulously take care of the hygiene of the breeding trays, with partial daily changes of about 20-30% of the water and suction of debris, food waste and dejections from the bottom. More substantial changes can be made only after the complete development of all the limbs, this is to avoid the sudden risk of death of individuals within a few hours due to osmotic/chemical stress.
As the larvae grow, you will also have to divide them by size from time to time, just to avoid any possible. At the same time, the diet can be further reviewed in favor of a greater number of preys or even larger ones.
As the age of the larvae increases, they will begin to pigment more and more until they become miniature versions of adults. At the height of larval development, the real metamorphosis phase will begin. The larvae will begin to develop their limbs more, and the cranial morphology characteristics becomes more similar to adults. If they have not been prepared previously, rocks, plants and/or pieces of floating cork or other suitable devices to create emerged areas must be distributed throughout the breeding tank, simultaneously with a lowering of the water level to about 2-3cm and the provision of a suitable cover. In parallel with those described above, other features to pay attention to are, in order of importance:
- reabsorption of the caudal membranes
- the first skin shed
- reabsorption of the gills
In fact, the gills can be completely reabsorbed even in a few hours and in any case the juvenile can still get out of the water, even with developed gills. The metamorphosis is completed in a period oscillating between 3 – 8 months. Sporadically it can occur even earlier (already at 7 weeks) or even much later, with wintering larvae. The size of the metamorphoses is approximately 4 – 7.5 cm.
Once the metamorphosis is complete, the juveniles will present themselves as miniature versions of the adults.
The background coloring, may undergo significant changes during the life of the animal both in colour (passing from decidedly yellow spots, gradually towards a paler color up to a dirty white), and the number and shape of the spots. These spots, although in some cases can be irregularly shaped, will tend to become more circular over the years and increase in size, especially in animals from the locality of Aqrah in Iraq.
Unlike what happened years ago, with mass deaths without apparent cause, currently the management of the juveniles is very simple. Often they can be induced with almost no difficulty to remain aquatic and in this case the keeping will remain practically identical to that of the larvae, as long as there are some emerged areas and an escape-proof lid.
Another solution is to leave them in a terrestrial environment for a period of time, potentially until they reach a reproductive age. In this case, care should be taken to ensure the terrarium is not too humidity, while also ensuring adequate ventilation, possibly by arranging at least two large air intakes on two different levels. Various arthropods (the usual crickets, woodlice, cockroaches, bean weevils), annelids (whiteworms, earthworms) and occasionally mealworm and waxworms may be used for feeding.
Finally, the last solution is the hybrid paludarium solution.
This species growth is quite rapid, considering that it is a mountain species, with individuals reaching 9-12cm a year after hatching and 11-14cm at 2 years. Sexual maturity is generally reached at an age of 4 years, but sometimes it is made possible even at an age of only 2 years and in any case at an average minimum length of 12cm.
Depending on where you are, this species is scarcely found, except for sporadic availability in some exotic animal expo. In recent years, however, reproductions at an amateur level are also increasing. The individuals with localities of known origin present in captivity to date all come from Aqrah, Iraq.
Of free sale and keeping, it is still recommended to always have a document left by the breeder of origin. In theory, they would be included within the Berne Convention, but an inclusion error still persists today, given that they have been included among the Anura and not among the Caudata.
The main difficulties in breeding are attributable to maintaining low temperatures for most of the year, to always ensuring excellent water quality and to the meticulous process to be followed for reproduction. In addition to the limited availability, especially for animals with known locations of origin.
These are quite robust and voracious newt, without intraspecific aggression and easy to manage once its biology has been thoroughly studied. Given the sometimes chaotic situation within the Neurergus genus, it would be better to research and breed only animals with known locations of origin.
Like all Neurergus, it seems to be the healthy carrier of some pathogens, such as bacteria of the genus Chlamydia. It is therefore essential to always take care of hygiene perfectly in order to avoid diseases induced by these microorganisms, as when they occur, these can both cause serious losses in a short time and become chronic, making the management of the disease very difficult.
About the Author...
Andrea Aiello, born in Florence in 1988, immediately gained a deep interest and fascination for nature and scientific-medical subjects. In 2012 he graduated in Biological Sciences from the University of Florence. He is currently pursuing a degree in Medicine and Surgery at the University of Florence.
From 2013 to 2018 he is a member of the Paolo Malenotti Foundation.
He has been breeding Caudata amphibians since 2008, mainly interested in Middle Eastern species (especially of the genus Neurergus) as well as the Plethodontidae family.
He is also fond of Orchids and Carnivorous Plants, of which he has a modest collection, which began in 2005. Other passions include Photography, Fishing, Herping, Trekking and Hiking more generally.
“Once I am settled, I would like to dedicate part of the new home to the breeding of other species of Urodeles and to the cultivation of tropical plants in greenhouses. At that point I would be delighted to be able to start keeping some Anura amphibians.”
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Citation: Najafi-Majd, E., & Kaya, U. (2013). Rediscovery of the Lake Urmia newt, Neurergus crocatus Cope, 1862 (Caudata: Salamandridae) in northwestern Iran after 150 years. Amphib. Reptile Conserv, 6(4), 36-41.
Citation: Rancilhac, L., Goudarzi, F., Gehara, M., Hemami, M. R., Elmer, K. R., Vences, M., & Steinfarz, S. (2019). Phylogeny and species delimitation of near Eastern Neurergus newts (Salamandridae) based on genome-wide RADseq data analysis. Molecular phylogenetics and evolution, 133, 189-197.
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