SPAIN 2011

 

 

Amphibia: ANURA (Frogs)

We recorded five species of anurans (tailless amphibians ie. frogs and toads) from four families, but probably missed other species in the ponds at Zarzalejo.

Alytidae:

Alytes cisternasii - Iberian midwife toad
One of three midwife toad species in mainland Spain, this species can be identified by the presence of two subequal tubercles on the palms of its hands. Midwife toads are nocturnal and it is the males that carry the fertilized eggs around, often the eggs of several females, for several weeks until they are ready to hatch. He then deposits them in watercourses. The Iberian midwife toad is the smallest of the mainland species (30-40 mm) and confined to the southwest and centre of the Iberian Peninsula.

The male photographed was found byJuan Timms and mentioned it to me as we left the "colubrid site" near Valdemorillo late on the final evening. We retraced his steps and found the same rock and were able to confirm and photograph the toad. It was found with two Natterjack toads (Epidalea calamita) to which it bears a resemblance (sans eggs) and it seems likely we overlooked females and males without eggs when we flipped other rocks and found 'only natterjacks' around this particular site.

Iberian midwife toad,
Alytes cisternasii

a male with eggs from Valdemorillo
click on the images to enlarge

two subequal palmar tubercles distinguihsing Alytes cisternasii
f rom other
Alytes species indicated by arrows

Bufonidae:

Bufo bufo bufo - Common toad
A relatively large species (100-180 mm) and one of the most instantly recognisable and frequently encountered amphibians in Europe, the Common toad (Bufo bufo bufo) was not found to be as common as the Natterjack road (Epidalea calamita) in the locations where we searched. We found two specimens alongside the river at Robledondo and although both had smoother skin than Common toads in the UK, and we considered they might be specimens of the Sierra de Gredos toad (B.b.gredosicola), the Sierra de Gredos is located over 100 km to the southwest and our specimens were neither small, nor possesses exceptionally large parotoid glands, as characterised for that subspecies. One specimen was coloured like a Sierra de Gredos toad but the other was classic Common toad. Until we learn that the montane subspecies ranges into Madrid Province we will treat our specimens as the widespread European taxa.

Common toad,
Bufo bufo bufo

two differently coloured specimens from Robledondo


Epidalea calamita - Natterjack toad
A rare and completely protected species in the United Kingdom, this was probably the frequently encountered amphibian on the trip, being found under rocks around the ponds and in the woods at Zarzalejo and along the stream banks at Valdemorillo. This species also demonstrated a wide range of colours, even in the same location. Also known as the "running toad" due to its more mouse-like gait, this is a small species (80-90 mm). Whilst the Natterjack is confined to sandy heathland habitats in the UK, it is distributed virtually everywhere, except above 2,500 m, in the Iberian Peninsula.

Natterjack toad,
Epidalea calamita

two differently coloured specimens from Zarzalejo and Valdemorillo

 

Hylidae:

Hyla molleri - Iberian treefrog
A single male was found at the Zarzalejo pool site, in long rushes alongside one of the pools. This species, which was elevated from synonymy within the widespread European treefrog (H.arborea), can be distinguished from the Stripeless treefrog (Hyla meridionalis) of southern Iberia by the presence of a broad lateral body stripe and short transverse dark bars on the back above the hindlimbs. This is a small frog (50-60 mm) found in vegetated habitats, especially associated with water, across much of Europe, except the south where it gives way to other species, the UK and Scandinavia. In Spain it may be found to 2,000 m altitude.

Iberian treefrog,
Hyla molleri

a calling male from Zarzalejo

 

Ranidae:

Pelophylax perezi - Iberian water frog
A common frog achieving medium size (70-100 mm) encountered in the pools at Zarzalejo, the stream at Valdemorillo and the river at Robledondo. The distinguishing characteristic of this frog, which is naturally confined to the Iberian Peninsula and southern France (it has been introduced into the Balearics, Canaries, Azores, Madeira and Kent, UK) is the middorsal yellow stripe. All specimens captured were juveniles and it remains a question whether the large green frog that escaped the dipnet at Zarzalejo, on the first night, was this species or a different ranid.

Iberian water frog,
Pelophylax perezi

specimens from Zarzalejo and Robledondo