Astypalaia & Naxos, 25.3.-3.4.2016

Hellas reloaded: After almost two years without a Greece trip we definitely had to go back! This time, we visited the Aegean Islands of Astypalaia and Naxos and their wall lizards. On Naxos we also hoped to see Sand Boas and Four-lined Snakes. Thanks to Philippos Katsiyiannis, Panayiotis Pafilis & Jonathan Webster!

25.3. – Stopover in Athens

Our flight from Düsseldorf to Athens started at 4 p.m. As our connecting flight to Astypalaia was scheduled for the next day, we spent one night in Athens: Once in our life we wanted to visit the Acropolis.

26.3. – To the islands!

8 a.m. & bright sunshine: Despite of numerous tourist groups from all over the world we really enjoyed our walk to the Acropolis. Four hours later we boarded on Olympic flight to Astypalaia. At Astypalaia airport we were picked up by the host of our accommodation. We dropped the luggage in our room, bought some food and finally were ready for herping.

Astypalaia is a rather remote Island, situated in between the Cyclades and the Eastern Aegean Islands of Dodecanese. However, on Astypalaia (and some of the uninhabited surrounding islets), there can be found a subspecies of Erhard’s Wall Lizard (Podarcis erhardii syrinae) which has been described by Wettstein (1937). By itself, this is not too remarkable: In the early 20th century, overzealous herpetologists have described different Podarcis erhardii subspecies for almost every Aegean island – the current taxonomy still mentions 18 subspecies for the Aegean although it is obvious that most of them should be regarded as synonyms.

Anyhow, a genetic analysis of Greek wall lizards by Poulakakis et al. (2005) piqued our interest: The results of this analysis suggest that Erhard’s Wall Lizard from the south-eastern Cyclades differ genetically from their relatives on the central Cyclades. Though, Poulakakis et al. (2005) do not go into detail about this result. Panayiotis Pafilis told us, that possibly the Astypalaia lizards could be something special. We did some internet research and found that there were obviously no publicly available pictures of these lizards. Therefore, we were curious to get some own shots of the Astypalaia lizards. Our expectations were low as most of the Cyclades subspecies of Erhards Wall Lizard look rather similar. Even more we were surprised as we finally saw those lizards…

The first lizards: Podarcis erhardii syrinae had been described some 80 years ago but as far as we know, there had been no publicly available pictures of that subspecies so far.

Whereas most of the Podarcis erhardii subspecies from the Cyclades look very similar, the subspecies syrinae looks quite different.

It’s a compact, robust lizard with massive head

One of the very few blooming orchirds: Ophrys ferrum-equinum

27.3. – Goats and lizards

We hired a car to explore the island: the western part of the island turned out to be a treeless schist rock with grazing goats; the eastern part turned out to be a treeless limestone rock with grazing goats. Overgrazing is for sure an issue on Astypalaia. Anyhow, Podarcis erhardii is abundant everywhere on the island, as well as Kotschy’s Gecko (Mediodactylus kotschyi). So we did another photo session with the lizards.

View to the village of Livadia, like an oasis in the dry landscape

Lizard-Safari in a Fuerteventura-like scenery

Podarcis erhardii syrinae has a big collar

Podarcis erhardii syrinae with a dark head - probably caused by an injury

28.3. – The complete Herpetofauna…

We only had seen 2 of the 4 Astypalaian herptiles: Besides of Podarcis erhardii and Mediodactylus kotschyi also Hemidactylus turcicus and Pelophylax bedriagae occur on this island. The occurance of Pelophylax bedriagae on Astypalaia is remarkable: It is the only population of this species west of the Mid Aegean Trench, which separates the European from the Asian herpetofauna. We do not know if it is an autochthonous population or if the frogs have been introduced. Of course we wanted to see them. And certainly we had another photo session with the fascinating Astypalaian Wall Lizards. Some (preliminary) considerations on those poorly known lizards can be found at the end of this report.

Sunrise with Nisiros Island in the far back

The occurance of Pelophylax bedriagae on Astypalaia is remarkable: It is the only population of this species west of the middle Aegean trench, which separates the European from the Asian herpetofauna.

For Podarcis erhardii, the middle Aegean trench near Astypalaia marks the distribution limit (with one exception on an uninhabited islet near Nisiros). On the Eastern Aegean Islands this species is replaced by the genus Anatololacerta.

In its appearance, Podarcis erhardii syrinae resembles to Pori wall lizards (Podarcis levendis)

Now we had seen the complete Herpetofauna of Astypalaia – maybe we should write a field guide now? ;-)

29.3. – Passage to Naxos

Naxos is the biggest island of the Cyclades with a herpetofauna of respectable 15 species. Anyhow, we couldn’t find much information about herping spots on that island. Most field herpetologists seem to prefer other islands. Therefore we more or less had to trust our luck. Besides of Podarcis erhardii we also hoped to see the local subspecies of the Balkan Wall Lizard (Lacerta trilineata citrovittata) as well as Sand Boas (Eryx jaculus) and the Four-lined Snake (Elaphe quatuorlineata) on Naxos.

We took the 5 o‘clock ferry from Astypalaia via Amorgos and Donousa to Naxos, where we arrived at 9:30 a.m. Pick up the rental car, bring the luggage to the accommodation – and start herping! First, we visited a rocky habitat near Naxos city, where we found Podarcis erhardii naxensis, Mediodactylus kotschyi, Hemidactylus turcicus, Stellagama stellio and Eryx jaculus – a good start! Afterwards we went to a coastal habitat further north where we hoped to find Natrix natrix: No Grass Snakes there but at least some Ablepharus kitaibelii. Unfortunately we didn’t manage to take pictures of this. Our next station was the promising Potamia valley with its lush landscape and a nice river. Also here, we saw Podarcis erhardii, Mediodactylus kotschyi and Stellagama stellio – these species are abundant everywhere on the island. At the river, we found Pelophylax kurtmuelleri and a juvenile Mauremys rivulata – but again, no Grass Snakes (finding this species should turn out to be rather tricky).

Podarcis erhardii naxensis – compared to the Astypalaia lizards the specimen from Naxos are quite colourful.

Grass snake habitat – without Grass snakes

30.3. – Sightseeing in the North

We went to the north of the island near Appolonas with its forests and creeks to search for Lacerta trilineata and Natrix natrix. The result: nice landscapes but only the usual suspects: Podarcis erhardii, Stellagama stellio and Mediodactylus kotschyi. In the afternoon, we were back in the centre of the island, where we finally spotted a single Lacerta trilineata.

Ophrys thesei: an endemic plant of the Cyclades

Lacerta trilineata citrovittata: This species seems to be not too common on Naxos, during our whole trip we only saw 6 specimens. Usually, they hide under bushes; we never noticed them basking on the road as they often do elsewhere.

31.3. – Snake safari

We went to the centre of the island to search for snakes – and it worked: soon, we found a juvenile Elaphe quatuorlineata as well as Eryx jaculus. Afterwards, we spent the noon in a dune habitat on the west coast, were we found Bufo viridis under stones. In the afternoon, we came back to the spot where we found the snakes in the morning – and it worked again: Vipera ammodytes. Furthermore, we spotted a lot of Ablepharus in the meadows and under the thorny bushes some Lacerta trilineata were basking. Maybe our most successful day on Naxos!

Snakes, finally: Juvenile Elaphe quatuorlineata muenteri – the second new species for us!

Ruin of an unfinished hotel in the dunes…

Lacerta trilineata citrovittata: The specimen from Naxos didn’t have blue heads like it is known from Tinos. We don’t know if the Lacerta trilineata from Naxos has no blue heads in general or if we just were too early in the season.

Lacerta trilineata citrovittata – these „Green Lizards“ with brownish colours are quite confusing…

01.04. – Driving a lot

We went to the south coast to try our luck at a coastal habitat: nothing but some very shy Mauremys rivulata. The southern part of the island turned out to be overgrazed and not very promising. Hence, we went back to the centre. In the oak forests at the slopes of Mount Zas we came across some nice coloured Podarcis erhardii naxensis and a very shy Lacerta trilineata. In the afternoon we explored the eastern part of the island which turned out to be overgrazed and dry, as well. In the evening we re-visited the snake spot where we had been the day before and found some Eryx jaculus and also Hemidactylus turcicus.

Beautiful male of Podarcis erhardii naxensis

Podarcis erhardii naxensis with blue flanks

02.04. – Two final highlights

There still was the issue with Natrix natrix: We gave it another try and went to Potamia valley once again... and found frogs and turtles, but no Grass Snake. Frustrating… We left the valley and went to a mountain meadow to photograph some flowers and do some breathing-exercises to optimize our vibrations. Afterwards, we started a last attempt in another valley. Here, we finally found the Grass Snake! We spent the afternoon at the coast, without spectacular findings. In the evening, we explored an olive grove in the heart of the island... and couldn’t believe it: just at the end of the trip we somehow “stumbled” over a big adult Elaphe quatourlineata. What a finale grande!

Pelophylax kurtmuelleri and Mauremys rivulata

Habitat of Pelophylax kurtmuelleri, Mauremys rivulata and Natrix natrix

Natrix natrix – specimen from Naxos are supposed to be N. n. persa x N. n. schweizeri: persa stripes and schweizeri blotches. Anyhow, on other Greek islands we had seen similar animals.

The centre of Naxos has big olive trees – and big snakes:

03.04. – Departure

After a full week of sun the weather was windy and cloudy now. But we didn’t care: our flight from Naxos to Athens started at 9:30 a.m. and we arrived back home at 4 p.m.

We had a splendid Aegean trip: Although Naxos has a reputation of an all-inclusive destination with mass tourism, in particular the centre of the island turned out to be calm with interesting and varied habitats. The species diversity is big – compared to other Aegean islands: 15 herptile species have been described for Naxos and we had seen 13 of them. We only missed Hyla arborea and Xerotyphlops vermicularis.

(Preliminary) considerations on Podarcis erhardii on Astypalaia

Podarcis erhardii syrinae has been described by Wettstein (1937) for the uninhabited islands of Syrna and Dio Adelfia south of Astyplaia. He considered the lizards of Astypalaia as a “mixed population” of P. erhardii syrinae and P. erhardii naxensis. Chondropoulos (1986) finally assigned the Astypalaia lizards to subspecies P. erhardii syrinae.

Wettstein’s description is not very precise but he mentions the following characters (among others): „A compact, plump form of normal size […] underside greyish-yellow to greyish-green. Underside of head without black spots…“

According to our observations, the lizards of Astypalaia differ significantly from their relatives on the central Cyclades (e.g. on Naxos).

Body colouration:

The most conspicuous character of P. erhardii syrinae is the usually brown colour on the flanks with small pale spots, in general without black markings. The outer belly scales of males often show only small blue spots, frequently only on every second scale. There are no additional blue or green colours on the flanks. Overall, in lateral view this subspecies looks monochrome brownish. The back has dark markings and green colours in the front part, the belly and underside of tale are pale orange, as it is common in other Aegean P. erhardii populations.

Head colouration:

In most P. erhardii from the Cyclades the dark flank stripe is continued from the ear opening to the eye. Throat and lower labials are frequently yellow or orange with black spots. These characters generate a contrasting head colouration. In P. erhardii syrinae, the heads look greyish-brown, rather monochrome. The dark stripe between ear and eye is weak, the underside of the head is greyish, never yellow or orange and has, as described by Wettstein, no black dots.

Scalation:

Wettstein points out that in P. erhardii syrinae the occipital is small and touches the interparietal – if at all – “only in one point”. In P. erhardii naxensis occipital and interparietal touch „in a broad seam“. In general, we can confirm these observations. But for us, this character is not diagnostic, as different variations of the occipital shape can occur in both subspecies. We didn’t find any additional single characters which can be diagnostic.

Body morphology:

In adults males of P. erhardii syrinae, the big collar which often reaches the neck is quite striking. Furthermore, P. erhardii syrinae appears – as described by Wettstein – “compact, plump”, the heads look massive with a somehow pointed snout. But, although these lizards look so different, these differences could only be quantified by a morphometric analysis.

Genetics:

An mtDNA-analysis by Poulakakis et al. (2005) suggests that P erhardii in the southern Aegean consists of 3 groups: a western group (Serifos, Sifnos und Kythnos), a central group (Naxos, Mykonos, Tinos, Amorgos etc.) and a south-eastern group (Astypalaia, Anafi and surrounding islets). Geological analyses (as well as the current see depth) indicate that Astypalaia has been isolated from the neighbouring Cyclades since at least 3.5 Mio. years. This could explain the independent evolution of the south-eastern group. But it has to be said that, as far as we know, on Amorgos (the closest Cyclades Island next to Astypalaia) there can be found among P. erhardii with “typical” Cyclades pattern also specimens which somehow resemble P. erhardii syrinae.

From our current point of view the lizards from Astypalaia (respectively the south-eastern group) should be regarded as a solid subspecies. Only genetic analyses can show if further taxonomic conclusions should be drawn. Anyhow, Podarcis erhardii syrinae is a good example how the Aegean works as a biodiversity-lab.

Literature:

Poulakakis, N. & Lymberakis, P. & Valakos, E. & Zouros, E. & Mylonas, M. (2005) - Phylogenetic relationships and biogeography of Podarcis species from the Balkan Peninsula, by bayesian and maximum likelihood analyses of mitochondrial DNA sequences. - Molecular Phylogenetics and Evolution, 37 (3): 845-857.

Wettstein, O. von (1937) - Vierzehn neue Reptilienrassen von den südlichen Ägäischen Inseln. - Zoologischer Anzeiger, 118 (3/4): 79-90.