The species epithet, "nebulosus," translates to “cloudy” or “fog” in Latin. However, the explanation of giving this name to P. nebulosus is unknown.

Description
Pleurodeles nebulosus is a medium-sized salamander with a snout-vent length range of 53.0 - 69.0 mm in males and 46.0 - 82.5 mm in females. The total length range is 94 - 230 mm. The head is moderately depressed with a width range of 10.0 - 13.6 mm. The interorbital width range is 4.28 - 5.8 mm. The head is smooth. The dorsal and dorsolateral surface is moderately to strongly turbulated or rugose. There is a lack of sharp rib tips and glandular swellings on the flanks. The tubercles are usually arranged in irregular transverse series that are separated by creases. The tubercles become smaller and more numerous towards the belly. However, the protuberances become less obvious in preservative. There is a gular fold present. The anterior arm length range is 17.2 - 24.0 mm; the length from elbow to the third toe ranges from 14.0 - 18.0 mm; the third toe length is 5.2 - 7.1 mm. Tail length range in males is 62.0 - 90.0 mm and in females is 48.0 - 97.0 mm (Carranza and Wade 2004). This species has a laterally flattened tail (Salvador 1996).

DIAGNOSIS:

As of 2023, three species of Pleurodeles are recognized: P. waltl, P. nebulosus, and P. poireti, all of which are found in North Africa (Ben Hassine and Escoriza 2014). Pleurodeles nebulosus is similar to P. poireti in coloration (Schleich et al. 1996), but can be differentiated by being larger, having a wider interorbital distance, and longer anterior arms. The focal species also has a more U-shaped palatine teeth row, instead of V-shaped as in P. poireti, and P. nebulosus has shorter teeth, and slightly curved skin tubercles, which appear less prominent and closer together than those of P. poireti (Carranza and Wade 2004). Male P. nebulosus also have a longer tail, a longer, wider, more depressed head, and longer forearms than male P. poireti. From P. waltl, P. nebulosus can be differentiated by the latter being smaller and lacking yellowish spots on its ribs, sharp rib tips, and a glandular rows of swelling on the flanks (Schleich et al. 1996, Carranza and Wade 2004).

COLORATION:

In life, P. nebulosus is olive on its dorsal side and yellow with black spots on its ventral side (Schleich et al. 1996). In preservative, the dorsal coloration is dark and may have pale tubercles. The ventral surfaces are paler with the throat and the palms being a pale yellow-ochre color (Carranza and Wade 2004).

VARIATION:

There is some sexual dimorphism. Generally, males are smaller than females, and southern individuals are larger than northern individuals (Sparreboom 2014). Males also have significantly longer tails lengths relative to their snout-vent lengths and significantly longer anterior limb lengths (Carranaza and Wade 2004). During the breeding season male cloaca swells and the nuptial pads on the forelimbs turn reddish-brown (Sparreboom 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Algeria, Tunisia

View distribution map in BerkeleyMapper.

Pleurodeles nebulosus is endemic to Algeria and Tunisia, except in and around the Edough Peninsula (Carranza and Wade 2004). It ranges from north-central Algeria to the Cape Bon Peninsula in Tunisia (Amor et al. 2013) and from the wilaya of Mascara in the west to Tunisia in the east (Merabet et al. 2016). Despite this range, its actual habitat is very fragmented. Pleurodeles nebulosus can be found in humid environments close to rivers, watercourses, and stagnant bodies of water, but can also live in semi-arid areas (Joger 2003). More specifically, they are found in mesothermic broadleaf forests and scrubland. They also have a tolerance to altered landscapes like agriculture fields (Ben Hassine and Escoriza 2017, IUCN 2021). The species has been found from sea level to 1185 m above sea level (Merabet et al. 2016).

Life History, Abundance, Activity, and Special Behaviors
Pleurodeles nebulosus is a rare species that is crepuscular and/or nocturnal, but may be diurnal during the breeding season in the winter. The species is highly terrestrial during the non-reproductive season and aquatic during the reproductive season (Ben Hassine and Escoriza 2017, IUCN 2021).

This species is known to aestivate in the soil among plant roots during hot and dry periods (June - September/October) and can be found in groups of more than ten but can also be solitary (Amor et al. 2013, IUCN 2021). The species is generally less abundant in more semiarid regions but can be found in a variety of habitats (Ben Hassine and Escoriza 2017, IUCN 2021).

Vocalizations of this species include barks, clicks, squeaks, and whistles (ARKive 2016). - needs a better citation

The onset of the breeding season is variable depending on altitude and temperature, but is linked to the onset of rain between November and December and between February and May. Breeding occurs in moderate to large ponds that have a range of turbidity (though typically high), water chemistry, and aquatic vegetation. They may prefer warmer water with emerging vegetation. This broad range of breeding habits indicates they are ecologically plastic like other Pleurodeles species in northwest Africa (Ben Hassine and Escoriza 2014, 2017, IUCN 2021).

During breeding, the cloaca swells and the nuptial pads on the forelimbs turn reddish-brown in males (Sparreboom 2014, IUCN 2021). Courtship involves the male and female facing opposite directions, interlocking their arms, and rotating using their arms as the pivot. Once the male deposits the spermatophore, the pair rotates again to bring the female over the spermatophore where she can then collect it (Sparreboom 2014). Oviposition is aquatic (Donaire-Barroso et al. 2006, IUCN 2021).

Defensive behavior includes flattening the body and curling the tail (Sparreboom 2014).

In ponds, P. nebulosus can be found in sympatry with Bufotes boulengeri, Discoglossus pictus, Hyla meridionalis, Pelophylax saharicus, and Sclerophrys mauritanicus. It is possible that P. nebulosus prey on these anuran’s eggs and larvae (Ben Hassine and Escoriza 2014).

Pleurodeles nebulosus hybridizes with P. poireti in several locations. The majority of hybrids have P. nebulosus mitochondrial DNA, indicating this species is the maternal source. The two species share habitat type and niches, so it is hypothesized that they are mutually excluding the other species from their own ranges with their population densities (Escoriza et al. 2016).

Larva
At the larval stage where the hind limbs have well formed toes but the external gills are still fully developed, larvae have a total length range of 39.3 - 73.7 mm and a body depth of 7.0 - 11.8 mm. At hatching, they have three gills and elongated balancers on each side of their head. The balancers are lost within a few days. Hatchlings also have cone-shaped forelimb buds. They have pond type body morphologies (Ben Hassine and Escoriza 2014).

Larval P. nebulosus are smaller than larval P. walti (Ben Hassine and Escoriza 2014).

Larvae are present during the winter and spring, sometimes into the early summer (Sparreboom 2014, Ben Hassine and Escoriza 2017) and take 2.5 - 4 months to metamorphose, typically leaving waterways between March and June (IUCN 2021).

Pleurodeles nebulosus and other species in the genus serve as excellent models for sex determination because larval sex is influenced by external temperature (Schleich et al. 1996).

Larval P. nebulosus can be found in sympatry with larval Discoglossus pictus, Hyla meridionalis, and Sclerophrys mauritanicus (Ben Hassine and Escoriza 2017).

Trends and Threats
This species is considered to be rare and declining. It may be extirpated from Grombalia and the coastal plains of Tunis. Pleurodeles nebulosus is threatened by pollution, predation or competition by invasive Gambusia fish, road traffic deaths, and climate change (IUCN 2021). More specifically, while the species seems tolerant of some agricultural habitat modification (cereal monocultures), agricultural activities pollute their natural breeding sites (Donaire-Barroso et al. 2006, Ben Hassine and Nouira 2012, IUCN 2021). Gambusia holbrooki is an introduced, invasive species that can breed in the same isolated puddles that this species utilizes for breeding. During the breeding season, dead newts can be found on the road. Lastly, because the species cannot rapidly migrate, climate change may be a future problem (IUCN 2021).

The species can be found in protected areas in both Tunisia and Algeria. In Tunisia, they are found Ichkeul and El Feija National Parks and in Algeria they are found in the biosphere reserves of Taza, Theniet el Had, Djurdjura, Chrea, and El Kala National Parks. In addition, it is a protected species in Tunisia and is protected by the Executive Decree 12-235 in Algeria (IUCN 2021).

Relation to Humans
Pleurodeles nebulosus is found in the pet trade and in captive populations (Sparreboom 2014, IUCN 2021).

Possible reasons for amphibian decline

General habitat alteration and loss
Disturbance or death from vehicular traffic
Predators (natural or introduced)
Introduced competitors
Climate change, increased UVB or increased sensitivity to it, etc.

Comments

PHYLOGENETIC RELATIONSHIPS:

As of 2023, three species of Pleurodeles are recognized: P. waltl, P. nebulosus, and P. poireti, all of which are found in North Africa (Ben Hassine and Escoriza 2014). However, population genetic analysis of ND4 mtDNA and 12 polymorphic microsatellites in P. poireit and P. nebulosus indicate that the two species hybridizes in several locations. The same analyses show that P. nebulosus is split into three subclades of western, central, and eastern populations (Escoriza et al. 2016).

References
Amor, N., Kalboussi, M. and Said, K. (2013). 27 Conservation status of amphibians in Tunisia. In Stephen D Busack and Harold Heatwole (Eds.), Amphibian Biology, Volume 11, Part 2 Status of Conservation and Decline of Amphibians: Eastern Hemisphere: Northern Africa (pp. 85-100). Asociación Herpetológica Española.

Ben Hassine, J., and Nouira, S. (2012). The Amphibians of Tunisia: Biodiversity, Distribution, Status and Major Threats. FrogLog 101, 32-34. [link]

Ben Hassine, J. and Escoriza, D. (2014). New ecological data on the family Salamandridae in the Mahgreb. Herpetological Review 45(2), 1-5. [link]

Ben Hassine, J. and Escoriza, D. (2017). Amphibians of Algeria: New data on the occurrence and natural history. Herpetological Bulletin 142, 6-18. [link]

Carranza, S., and Wade, E. (2004). Taxonomic revision of Algero-Tunisian Pleurodeles (Caudata: Salamandridae) using molecular and morphological data. Revalidation of the taxon Pleurodeles nebulosus (Guichenot, 1850). Zootaxa, 488(1), 1-24. [link]

Escoriza, D., Gutiérrez-Rodríguez, J., Ben Hassine, J. and Martínez-Solano, I. (2016). Genetic assessment of the threatened microendemic Pleurodeles poireti (Caudata, Salamandridae), with molecular evidence for hybridization with Pleurodeles nebulosus. Conservation Genetics, 17, 1445-1458. [link]

Donaire-Barroso, D., Salvador, A., Slimani, T., El Mouden, E. H., Geniez, P. and Mateo, J. A. (2006). Pleurodeles nebulosus. (errata version published in 2016). The IUCN Red List of Threatened Species 2006: e.T61919A86178127. Downloaded on 16 February 2017.

IUCN SSC Amphibian Specialist Group. 2021. Pleurodeles nebulosus. The IUCN Red List of Threatened Species 2021: e.T61919A179948304. https://dx.doi.org/10.2305/IUCN.UK.2021-3.RLTS.T61919A179948304.en. Accessed on 26 October 2023.

Joger, U. (2003). Reptiles and amphibians of southern Tunisia. Kaupia, 12, 71-88.

Schleich, H. H. , Kastle, W., and Kabisch, K. (1996). Amphibians and Reptiles of North Africa. Koeltz Scientific Books Publishers, Koenigstein.

Merabet, K., Dahmana, A., Karar, M., and Moali, A. (2016). New occurrence record of the Algerian ribbed newt Pleurodeles nebulosus (Guichenot, 1850) in Algeria. The Herpetological Bulletin, 137, 43. [link]

Salvador, A. (1996). Amphibians of Northwest Africa. Smithsonian Herpetological Information Service, 109, 1-43. [link]

Sparreboom, M. (2014). Salamanders of the Old World: The Salamanders of Europe, Asia and Northern Africa. BRILL. pg. 304.

Species Account Citation: AmphibiaWeb 2024 Pleurodeles nebulosus: Algerian Ribbed Newt <https://amphibiaweb.org/species/6288> University of California, Berkeley, CA, USA. Accessed Nov 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Nov 2024.

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