Alytes maurus

This species has often been referred to as a subspecies of Alytes obstetricans, but has recently been promoted to the species level (Donaire-Barroso et al. 2008).

The specific epithet “maurus” is Latin for “Moorish” which can be generalized to mean “African.” This name is appropriate, as Alytes maurus is the only African member of its genus (Martínez-Solano et al. 2004).

The authors of the original description were unable to distinguish Alytes maurus from its close relative A. obstetricans based on adult morphology (Pasteur and Bons 1962). Alytes obstetricans is a small, stocky frog with relatively large head. The eyes are large and have a vertical slit-shaped pupil. Parotid glands are small, and the tympanum is mostly visible. The skin is warty, and a row of large, often reddish warts extends from the tympanum to the loin area. Other large gland complexes are present on the underarms and the ankles. Three metacarpal tubercles are present (Noellert and Noellert 1992).

Males and females can be distinguished by size (males smaller than females), the distance between nostrils, the distance between the anterior end of the middle metacarpal tubercle and the tip of the third finger, and the distance from the elbow to the third finger tip. These variables should be corrected for the size of the animal (Bosch and Marquez 1996).

Dorsal coloration can varies with individuals exhibiting small black dots, brown dots to olive or green spots. The venter is whitish, and the throat and the chest are often spotted with gray (Noellert and Noellert 1992).

The frontoparietal bone has an absent or poorly developed medial process, not extending to the sagital axis. It has a paraoccipital process, a double fontanelle separated by the medial processes of the frontoparietal with a slight constriction at the point of separation, and the lateral margin in the orbitary area clearly protrudes with respect to the anterior portion of the lateral margin. The maxillar lacks a posterior process, a zygomaxillar process, a pterygoid process, and a palatine process, and there is no longitudinal groove in the base of the teeth row. The nasal bones have short maxillar processes that do not reach the maxillar, rostral processes roughly one-fourth of the length of the nasal, and the ratio of total length to maximum width, measured at the level of the maxillar process, is slightly greater than or equal to one. Paraoccipital crests are absent. The parasphenoid has a long posterior process that clearly surpasses the posterior margin of the parasphenoid allae. It also has a uniformly wide, generally pointed cultriform process and lacks transverse keels in the allae, which are uniformly wide or narrowing distally. The number of premaxillary teeth is between ten and thirteen. The prootic process is elongated and narrow, extending over the external border of the orbital fossa and reaching the internal border of the pterygoid fossa. The pterygoid possesses a ventral expansion. The sphenethmoid consists of two paired pieces incompletely fused together, with a short anterior process that does not surpass the anterior margins of the lateral processes of the sphenethmoid. These lateral processes narrow distally. In a dorsal view, the zygomatic rami of the squamosals diverge rostrally in posteromedial-anterolateral orientation. The otic and interior rami are well developed, grown to one-third to one-half of the total length of the squamosal (measured from the apical end of the zygomatic ramus to an axis connecting the distal ends of the otic and interior rami), with the zygomatic ramus elongated over twice the length of the otic ramus. The posterior choanal process of the vomer is uniformly wide and bifurcated.

Adapted by Dietterich from a character matrix developed by Martínez-Solano et al. (2004).

This stocky frog exhibits a relatively large head, large eyes, vertical slit-shaped pupils, small parotid glands, and warty skin with a row of large, often reddish warts extending from the tympanum to hind limb insertion. Adults of this species are difficult to distinguish from A. obstetricans, but tadpoles can be distinguished by the presence of a pigmented network of chromatophores that follows a very loose and irregular grid structure, a dark trisegmented border on the lower jaw, an interorbital distance that is smaller than the size of the mouth, and a tooth morphology that differs from A. obstetricans.

The IUCN Red List (2008) categorizes this species as Near Threatened because although the species appears not to be in decline, its Extent of Occurrence is less than 5000 km2, thus making the species close to qualifying for Vulnerable (Donaire-Barroso et al. 2008).

It occurs in a number of protected areas. Conservation techniques include land/water management, site/area management, education, awareness, and communications (Donaire-Barroso et al. 2008).

The main threat to this species is considered to be the introduction of the predatory fish Gambusia holbrooki to breeding ponds. Domestic water pollution is also a threat to the population in Chauen, although other populations in the surrounding area are not threatened by this contamination. Overall, the threats facing this species are currently localized, and it is not believed to be seriously threatened at present (Donaire-Barroso et al. 2008).

The introduced fish Gambusia holbrooki is believed to prey on Alytes maurus tadpoles (Donaire-Barroso et al. 2008).

The adult form of Alytes maurus is extremely similar to A. obstetricans, but the tadpoles have some distinguishing features. In particular, tadpoles of A. maurus have a pigmented network of chromatophores that follows a very loose and irregular grid structure in comparison with the more regular grid of A. obstetricans. The lower jaw of A. maurus tadpoles has a dark trisegmented border that is absent in A. obstetricans, and in A. maurus the distance between the eyes is distinctly smaller than the size of the mouth. A. maurus tadpoles also differ from A. obstetricans tadpoles in tooth morphology, in particular by having the upper anterior tooth row comprised of two rows of uniform density, and each other tooth row containing at least one more row than in A. obstetricans (Pasteur and Bons 1962).

This species is restricted to the western and central Rif Mountains and middle Atlas Mountains of Morocco. It is known only from about twenty fragmented localities, from 200-2,050 m asl (Donaire-Barroso et al. 2008). It is not present in the North African Spanish enclave of Ceuta (Mateo et al. 2003).

The detailed phylogeny, biogeography, and evolutionary history of the genus Alytes are still active areas of study (Martínez-Solano et al. 2004; Gonçalves et al. 2007). Alytes maurus has been consistently grouped with A. muletensis and A. dickhilleni in what is called the Baleaphryne clade, although relationships within this clade, or between this clade and other Alytes species are still incompletely understood. According to Martínez-Solano et al. (2004), the genus Alytes originated in the Iberian Peninsula before 18 Ma, with A. maurus diverging from the other two Baleaphryne species approximately 5-8 Ma.

Mitochondrial 16S and cyt-b sequences exist under GenBank accession numbers AY442019-AY442026, AY514027-AY514035, and AY442027-AY442036 (16S, 16S, and cyt-b, respectively) (Martinez-Solano 2004). Gonçalves et al. (2007) have also sequenced the mitochondrial gene ND4 and surrounding tRNAs, and the nuclear intron ß-fibint7 for A. maurus and several other Alytes species, and inserted them into GenBank under the accession numbers EF441291-EF441343.

Tadpoles are 24-56 mm long. Tadpole body length is 55-77% (mean 62; n = 8) of the length of the tail. The distance between the extremities of the lips is 2.1-2.8 times (mean 2.5; n = 8) the distance between the nostrils. The distance from the tip of the snout to the opening of the spiracle is 58-79% (mean 72) of the distance from the spiracle to the base of the anal tube. The size of the mouth (distance between the extremities of the lips) is 10.8-13.8% (mean 12.3; n = 7) of the total length.

The lengths of the lower two (out of three) posterior tooth rows are approximately equal. The upper anterior tooth row is entirely double with the two rows of teeth of regularly equal density; in 10 samples, once triple in the central 2/5, once triple in the central 5/7, and once entirely triple. The lower anterior tooth row is at least triple; partially or completely quadruple in all tadpoles that began to grow posterior legs after reaching approximately 4 cm. The upper posterior tooth row is at least triple in its central third in small tadpoles, at least in its central half in tadpoles 4 cm or longer, and even largely quadruple in 7 out of the 9 of these. The middle posterior tooth row is always double at the extremities, triple at least in the central 2/5, and partially quadruple (up to 3/4 of the tooth row) in 6 of the 9 tadpoles longer than 4 cm. The lower posterior tooth row is at least double, with a third row represented 11 times out of 12 but very unevenly (from 8 teeth to the central 3/5 of the tooth row).

Additionally, tadpoles of A. maurus have a pigmented network of chromatophores that follows a very loose and irregular grid structure, and, commonly, a dark trisegmented border on the lower jaw, with the outer segments more prominent than the inner segment. The distance between the eyes is distinctly smaller than the size of the mouth (Pasteur and Bons 1962, translated/adapted by Dietterich 2010).

This species is generally found in humid sites in montane karst and escarpment areas. Adults inhabit cracks and fissures in rocks, or live under stones close to permanent streams, pools, and other bodies of water. Surrounding vegetation may be scrub, cork oak groves, and orchards (Donaire-Barroso et al. 2008).

Alytes maurus adults are very similar in morphology to A. obstetricans, but they occupy different ranges (A. maurus occurs only in Morocco and is the only known African species of Alytes, whereas A. obstetricans and other distinguishable Alytes spp. occur in Europe or on nearby islands) (Martínez-Solano et al. 2004).

Suitable habitats for this species are uncommon and fragmented across the range of the organism, but in appropriate habitats it can be quite common (Donaire-Barroso et al. 2008).

It spawns in water, producing approximately 60 eggs at a time (with 3-4 clutches a year), which are then carried around outside the water by the male, who releases the larvae back into water at the point of hatching (Donaire-Barroso et al., 2008).

Adult frogs have snout-vent lengths up to approximately 55 mm (Noellert and Noellert 1992), although females may tend to be larger than males (Bosch and Marquez 1996). The holotype is a female measuring 32 mm long (Pasteur and Bons 1962). Tadpoles can reach and exceed 40 mm in length, with the body significantly larger than the tail (Pasteur and Bons 1962).