Description
Neurergus crocatus is a large-bodied newt, males having a maximum total length of 180 mm and females 160 mm (Schmidtler and Schmidtler 1975, Najafi-Majd and Kaya 2013). Baran and Öz (1986) reported snout-vent length of approximately 63.8 mm in males and a range of 56.6 – 70.3 mm in females, however, their specimens appear to be smaller than Schmidtler and Schmidtler (1975) and Najafi-Majd and Kaya (2013) specimens. The head is flattened and the snout is rounded. The nostrils are widely spaced. The eyelids are somewhat developed and there are small paratoids (Cope 1862). When adpressed, the limbs overlap (Cope 1862, Baran and Öz 1986). The ventral surfaces of the hands and feet are smooth. The digits are long and flattened, unadorned with fringes. The third and fourth toes are about equal in length (Cope 1862). Baran and Öz (1986) report that the skin is smooth and without wrinkles, however Cope (1862) indicated that the skin is tuberlated on the dorsum and somewhat corrugated on the lateral surfaces. This difference may be a result of breeding condition. During the breeding season, the lips of the cloaca protrudes 1 – 2 mm and the tail fin is both dorsally and ventrally developed with dorsal tail fin longer than ventral (Schmidtler and Schmidtler 1975 and Najafi-Majd and Kaya 2013). In general, the tail is laterally compressed with a round base, is longer than the body, and has a mild crest (Cope 1862).

The larvae have a total body length between 35 - 70 mm and a dorsal fin that protrudes from the center back (Schmidtler and Schmidtler 1975, Najafi-Majd and Kaya 2013). Larval morphology is adapted to living in streams with water currents by possessing low tails, low dorsal fins, and reduced gills with a long, slender body type (Steinfartz et al. 2002).

Neurergus crocatus can be differentiated from all members of Triturus, their sister genus, by males N. crocatus not developing dorsal crests during the breeding season (Wiens et al. 2010). Neurergus crocatus is easily distinguished from N. kaiseri by size, with N. kaiseri being significantly smaller and having a conical cloaca with larger protruding lips (Schmidtler and Schmidtler 1975). Neurergus crocatus, N. derjugini (formerly N. microspilotus), and N. strauchii are all similar looking species with bright yellow spots occurring on a grey-black ground color. However, N. crocatus can be differentiated from N. strauchii by the former having larger and less numerous yellow dorsal spots and a completely yellow to orange venter (Baran and Öz 1986, Schneider and Schneider 2010, Sparreboom 2014). During the breeding season, the cloaca in N. derjugini is more conical than N. crocatus. Additionally, in N. derjugini, the spots are more uniformly small on the dorsum and tail, and there are black spots on the orange throat and edges of the ventrum (Schmidtler and Schmidtler 1975, Najafi-Majd and Kaya 2013).

Larval Neurergus crocatus are generally larger than N. kaiseri, but the two can also be differentiated by coloration and patterning. Neurergus crocatus have a darker background background color with brighter spots. From the more similar N. derjugini and N. strauchii, N. crocatus can be differentiated by the latter having a longer dorsal fin that extends from the tip of the tail to just below the head and a brighter ventrum. Additionally, N. derjugini larvae have two broad dorsal stripes (Schmidtler and Schmidtler 1975, Najafi-Majd and Kaya 2013).

In life, Neurergus crocatus have a dorsal coloration, including the tail, of dark brown to black with small round yellow spots near midline and large light yellow spots in lateral positions. Their ventral side, including underside of legs and tails, is uniformly orange, reddish-orange in males and more yellowish-orange in females. The chin and ventral line of the tail are a paler color then the belly. During the breeding season, males become more shiny and their spots on the dorsal tail become white (Cope 1862, Baran and Öz 1986, Schnider and Schnider 2010, Najafi-Majd and Kaya 2013).

In life, the dorsal pattering of small larvae is light gray with irregular black spots. For larvae greater than 50 mm in total body length the spots are large, bright, and irregular. The more mature larvae belly is almost brightly unicolored and the tail is darkly pigmented (Schmidtler and Schmidtler 1975, Najafi-Majd and Kaya 2013).

Despite what had been previously presumed about the species, there seems to be distinct sexual dimorphism of coloration. The adult males have a few bright white spots in a single line down the tail, whereas the adult females have a few yellow and irregularly arranged spots on their tail. Males also appear to be smaller and more slender than females. More generally, most individuals have a large blotch at the base of their tail, however in some individuals this blotch is expanded into a band. The spots and blotches on the lateral surfaces of individuals may also extend onto the ventrum (Schneider and Schneider 2010).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Iran, Islamic Republic of, Iraq, Turkey

View distribution map in BerkeleyMapper.

Neurergus crocatus is native to Iran, northern Iraq, and southeastern Turkey. They reside in temperate forest and inland wetland habitats. This includes rivers, creeks, streams, and waterfalls (Papenfuss et al. 2009). The streams in which they are found are usually surrounded by thick riparian vegetation and are free of human activity (Schneider and Schneider 2010). They are found at an elevation between 1500 and 2000 meters (Papenfuss et al. 2009).

Life History, Abundance, Activity, and Special Behaviors
During the spring breeding season, N. crocatus can be found in cool, well-oxygenated mountain streams with sand or stone in dense riparian zones. Vegetation surrounding the streams include watercress (Nasturtium officinale), oregano (Origanum vulgare), and stinging nettle (Urtica dioica). In the winter, N. crocatus hibernates during the winter in terrestrial burrows or under stones (Najafi-Majd and Kaya 2013).

The breeding season depends on elevation (Papenfuss et al. 2009) and courtship occurs in montane streams. The courtship behavior for N. crocatus starts with males pursuing females and trying to position himself in front of her. The pair will stand more or less face to face as the male begins to fan his tail, beginning at the tail base and ending at the tip, making tail slaps approximately 4 cm away from a female. In N. crocatus specifically, the fanning lasts up to 25 seconds with approximately 3 tail beats per second. Soon after, the male deposits the spermatophore in front of the female and the female walks over the spermatophore to pick it up with her cloaca. Females deposit eggs in clusters of 20 - 40 eggs under flat stones (Sparreboom et al. 2002, Schnider and Schnider 2010). Yolks are yellow and approximately 2 mm (Schmidtler and Schmidtler 1975).

After courtship, the adults will leave the streams and go into the surrounding areas, although little is known about their terrestrial activity (Najafi-Majd and Kaya 2013).

Aquatic adults or larvae are thought to prey on larvae of stoneflies and other fly larvae found in streams (Schneider and Schneider 2010).

Trends and Threats
The major threats to N. crocatus are habitat loss due to agriculture, resource use, pollution, and climate change. Turkey is expecting to begin major development and dam construction within the species’ distribution, and thus will most likely be negatively impacted by such as well. Their distribution does not fall within any protected areas and their population has been steadily declining. Additionally, individuals are taken for the pet trade (Papenfuss et al. 2009).

Relation to Humans
Neurergus crocatus are found in the pet trade, but populations have drastically declined in captivity and they are no longer a popular pet (Papenfuss 2009).

Possible reasons for amphibian decline

General habitat alteration and loss
Intensified agriculture or grazing
Prolonged drought
Local pesticides, fertilizers, and pollutants
Intentional mortality (over-harvesting, pet trade or collecting)

Comments
Cope, E. D. 1862. “Notes upon some reptiles of the Old World.” Proceedings of the Academy of Natural Sciences of Philadelphia 14: 337–344.

As of 2019, there are five known species of Neurergus: N. barani, N. crocatus, N. derjugini, N. kaiseri and N. strauchii. Analysis based on over 8000 Restriction Site Associated DNA (RAD) sequences resulted in conflicting relationships within the genus. In one analysis, N. crocatus is sister to the clade that includes N. derjugini and N. kaiseri while Neurergus strauchii and N. barani are sister to the rest of the genus. However, a second analysis found that N. crocatus and N. derjugini are sister taxon, indicating low resolution in the true evolutionary relationships between N. crocatus, N. derjugini, and N. kaiseri (Rancilhac et al. 2019).

Speciation is suspected to have arisen in the genus due to sexual isolation through allopatric processes rather than sympatric processes (Rancilhac et al. 2019).

The genus name, “Neurergus” comes from the Greek “neuron” meaning ‘‘sinew” or “tendon’’ and “ergon” meaning ‘‘work’’ (Dubois and Raffaëlli 2009)

Aside from the Yellow Spotted Newt, the species has two other English common names: the Azerbaijan Newt and the Lake Urmia Newt (Sparreboom et al. 2002).

The species was not studied in Iran for approximately 150 years. Najafi-Majd and Kaya (2013) were able to confirm the species' existence in Northwestern Iran and expanded the range of N. crocatus.

References

Baran, İ., Öz, M. (1986). ''On the occurrence of Neurergus crocatus and N. strauchii in Southeast Anatolia.'' Zoology in the Middle East, 1(1), 96-99. [link]

Dubois, A., Raffaelli, J. (2009). ''A new ergotaxonomy of the family Salamandridae Goldfuss, 1820 (Amphibia, Urodela).'' Alytes, (26), (1–4) (1–85). [link]

Najafi-Majd, E, Kaya, U. (2013). ''Rediscovery of the Lake Urmia newt, Neurergus crocatus Cope, 1862 (Caudata: Salamandridae) in northwestern Iran after 150 years.'' Amphibian and Reptile Conservation , 6(4), 36-41. [link]

Papenfuss, T., Sparreboom, M., Ugurtas, I.H., Rastegar-Pouyani, N., Kuzmin, S., Anderson, S., Eken, G., Kiliç, T., Gem, E., Kaya, U. (2009). “Neurergus crocatus (errata version published in 2016).” The IUCN Red List of Threatened Species 2009: e.T14734A86247230.

Schmidtler, J. J., and Schmidtler, J. F. (1975). ''Untersuchungen an westpersischen Bergbachmolchen der Gattung Neurergus.'' Salamandra, 11, 84-98. [link]

Schneider, C. Schneider, W. (2010). ''Field notes on the ecology and distribution of Neurergus crocatus COPE, 1862 and Neurergus strauchii strauchii (Steindachner, 1887) in Turkey.'' Herpetozoa, 23(1/2), 59-69. [link]

Sparreboom, M. (2014). Salamanders of the Old World: The Salamanders of Europe, Asia and Northern Africa. Zeist, Brill, The Netherlands.

Sparreboom, M., Steinfartz, S., Schultschik, G. (2002). ''Courtship behaviour of Neurergus (Caudata: Salamandridae).'' Amphibia Reptilia , 21(1), 1-12. [link]

Steinfartz, S., Hwang, U. W., Tautz, D., Öz, M., and Veith, M. (2002). ''Molecular phylogeny of the salamandrid genus Neurergus: evidence for an intrageneric switch of reproductive biology.'' Amphibia-Reptilia, 23, 419-431. [link]

Wiens, J. J., Sparreboom, M., and Arntzen, J. W. (2011). ''Crest evolution in newts: Implications for reconstruction methods, sexual selection, phenotypic plasticity and the origin of novelties.'' Journal of Evolutionary Biology, 24(10), 2073-2086. [link]

Species Account Citation: AmphibiaWeb 2021 Neurergus crocatus: Lake Urmia Newt <https://amphibiaweb.org/species/4258> University of California, Berkeley, CA, USA. Accessed Nov 25, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Nov 2024.

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