Excursion into the distribution area of the Dalmatian tortoise
Testudo hermanni hercegovinensis, WERNER 1899
As early as 1899, WERNER described a species that occurs near Trebinje, Bosnia and which is very similar to the Greek tortoise as Testudo graeca var. Hercegovinensis. The Finnish systematist PERÄLÄ reintroduced this in 2002 as an independent species "Testudo hercegovinensis WERNER, 1899". However, due to the relatively small, sometimes not always present, distinguishing features, this species status cannot endure. The Dalmatian tortoise has already correctly been classified as a subspecies of the Greek tortoise Testudo hermanni hercegovinensis, as in a popular scientific paper by BLANCK & ESSER (2004).
In a new systematic study, the Greek tortoise is revalidated and described as a new genus Eurotestudo with the species Eurotestudo hermanni, Eurotestudo boettgeri and Eurotestudo hercegovinensis (DE LAPPARENT DE BROIN et al., 2006). Whether this controversial revalidation is valid or not according to the International Rules for Zoological Nomenclature (ICZN) no longer matters, since the generic name Eurotestudo has not caught on anyway.
For us turtle keepers, the exact taxonomic classification of the turtles is of secondary importance. In terms of keeping it does not matter whether one proceeds from the phylogenetic species concept, from a species or from a subspecies according to the biological species concept. The only thing that matters is the fact that among the Greek tortoises of the eastern subspecies that we keep there may be other species of animals.
In May 2005 and 2006, my son Manuel and I explored the Adriatic coast of the former Yugoslavia from northern Istria to the Albanian border area to give ourselves an overview of the morphology, the way of life and, above all, the distribution area of these "new" turtles combed for turtles.
The last time we were in Croatia, the turtles living there were still generally regarded as Testudo hermanni boettgeri. WERNER's description had been forgotten and was not known to turtle lovers.
The Dalmatian tortoise resembles the western subspecies in body shape, pattern and size and the eastern subspecies in color. In addition, it can have all the characteristics of the other two subspecies. The back armor is usually strong and contrasting colored and highly arched. The basic color varies depending on the area of occurrence from pale ocher yellow (southern and island populations) to dark olive (Istria). The keyhole markings on the 5th vertebral shield, like the yellow subocular spot, are more or less pronounced and relatively often present. However, both features can be completely absent.
The back of the head is always yellow-olive to olive in color. The color of the head, limbs and skin varies depending on the origin from lighter in the south to darker in the north. However, it is generally lighter than the eastern subspecies bordering on Montenegro. There are always individual light-colored scales on the limbs.
As with the western subspecies and some populations of the eastern subspecies, there are two black longitudinal stripes on the yellow olive-colored belly armor. However, in the case of the Dalmatian tortoise, these are always clearly separated from one another in the middle, overall much narrower and often also torn or blurred, which already rules out confusion with Thhermanni. The throat shields are, as in the western subspecies, almost always and the anus shields sometimes free of spots or only stained on one side. The spots on the arm shields and, if present, on the anus shields are generally clearly separated from the spots on the chest and leg shields.
The ratio of the central seam of the breast shields to the seam of the leg shields is too variable to be used as a distinguishing feature.
The size of the males is about 14 cm to 16 cm with a weight of 600 g to 800 g. The females are between 15.5 cm and 17.5 cm tall and weigh between 850 g and 1100 g. The northern population of the Dalmatian tortoise is also larger than the animals in the south.
The purpose of our trip was to examine as many different local populations as possible for comparison purposes. We did not want to track down a large number of turtles in the individual habitats, but only examine four individuals at a time. For this reason, the stay in the various areas was limited to a short period of time and was soon discontinued if no evidence of the presence of turtles was found. From the Slovenian border we began to examine individual areas that were suitable based on our experience, but we were not worried when we only found what we were looking for in southern Istria. From a geological point of view, Istria is only really suitable as a tortoise habitat in this area, because the northern area consists of gray sandstone and marl. From the south, the Istrian plate rises as a chalk-limestone plate to a height of 450 m and thus formed an ideal turtle habitat at least in earlier years together with the Mediterranean vegetation. Today Istria is already heavily sprawled and taken over by tourism and agriculture.
Although it is difficult to imagine due to the rest of the distribution area, the tortoises found in Istria are still assigned to Testudo hermanni boettgeri. The distribution area of the Dalmatian tortoise was only given by P ERÄLÄ (2002) from south of Zadar. This information is still taken over by some authors without checking. So we were a bit irritated at first when the first turtle we found had inguinal shields on both sides. These are the small triangular hip shields or, better, inguinal shields, which are usually present on both sides of the thigh cavity between the abdominal and peripheral shields in the western and eastern subspecies and should generally be absent in the Dalmatian tortoise.
The limbs and head of this 16 cm long male were relatively dark and had only a few olive-colored scales. However, the dark yellow olive-colored overall appearance of the carapace spoke more for the Dalmatian tortoise.
The next animal finally brought clarity, a male with the lower edge shields that are classically drawn inwards into the crook of the thighs and the inguinal shields that are missing on both sides. Two other animals, a 13 cm female and an adult male, also had no inguinal shields. All four turtles did not differ from one another in terms of their overall appearance. They were undoubtedly Dalmatian tortoises.
The area of discovery was a very rocky slope inclined to the south, steeply sloping in some places, the vegetation of which was very dense shrubbery with individual clearings and finally merged into a spruce forest. The bushes themselves consisted mainly of stinging juniper with a few Phoenician juniper bushes interspersed. In the clearings and even between and under the bushes, abundant flowering, juicy forage plants grew.
When I read in the Kosmos nature guide that the tar extracted from the wood of the stinging juniper was good against skin diseases, I found that ironic, as the extremely prickly juniper lived up to its name and caused skin ailments in our arms and legs to mitigate as such.
The approx. 1800 km long Croatian coastal region adjoining Istria is a very narrow strip up to a maximum of 15 km wide, with mountain ranges between 1200 and almost 1800 m high in some parts. These mountain ranges separate the coastal region with its Mediterranean climate from the continental climate zone in the interior. Because of this fact, tortoises can only be found in this coastal strip in Croatia. There is a strong temperature gradient between Istria in the north and the adjoining coastal region to the south, which at this time of year, for us especially at night, was noticeable and was even recognizable in the vegetation. We already experienced a warm summer night on the island of Pag.
As in the entire Mediterranean area, the forests that once existed on the Croatian coast were cut down for the construction of ships. Mainly between the 10th and 18th centuries, the Venetians built large shipyards on the offshore islands, which literally devoured the stately primeval forests. Various winds, especially the Bora, did the rest and left behind an inhospitable stone desert landscape. In some places even the last scanty humus remains have been carried away and only a few resistant, low bushes and herbs can cling to the stones. In large parts of the landscape you can only find scree slopes, which even the goat and sheep herds no longer provide any food.
The local farmers have always been painstakingly removing the stones by hand and filling up earth between the stone walls stacked like a checkerboard in order to plant at least olive trees, wine or some vegetables. Remaining stones are piled up to form walls or piles several meters high.
Even tortoises, which prefer stony terrain, have not been found in such areas for centuries. The limestones and rocks, which are white in themselves, are colored gray by the glowing summer heat. Some areas, especially on the offshore islands, resemble a lunar landscape.
The coastal region also offers rolling hills covered with more or less dense vegetation. Here there are still relatively original tortoise biotopes. These areas are only used as pastures. Unfortunately, the population density is relatively low compared to other countries such as Montenegro, Greece, or islands such as Sardinia. Before the great clear-cutting of the formerly wooded Mediterranean vegetation, the Dalmatian tortoise was also found in suitable regions across the board from Istria to northern Montenegro.
Large parts of these ranges of hills and in the plains also former agricultural areas are unfortunately still littered with landmines. Tortoise populations are noticeably recovering in these overgrown areas, which have been untouched for 15 years. We were able to find many animals of different age groups in a relatively short time, especially in the edge areas of these areas, which suggests that the populations in the mined areas have stabilized again. For us turtle friends, however, this is in no way pleasant, because these areas will certainly have to be cleared from the mines at some point. Due to the rocky structure, however, mine clearance vehicles can only be used to a limited extent. The farmers make do with this by burning down these areas in order to trigger the mines with the fire. This also means the end for most of the turtles living there. Few turtles survive such wildfires, often with severe burn injuries.
In agriculturally used areas, tortoises are largely no longer present. An old farmer told us that there had been no tortoises around her fields for many years and was visibly happy about it.
As I have already reported in my books, the “residual turtles” still partially occurring elsewhere in such cultivated areas have no chance of survival anyway.
In another agricultural area adjacent to dense, mined maquis , a farmer told us that the turtles were already getting out of hand in his fields again. A short time later his wife brought us a semi-adult female out of the field and insisted that we take the turtle with us. We finally carried the animal into the maquis.
Land turtles are still viewed by farmers as pests and also as food competitors for their goat and sheep herds and are still slain.
According to our findings, the distribution area of the Dalmatian tortoise extends from southern Istria to the Neretva including the estuary and up the valley to the Mostar area. Sympatric occurrences, with Testudo hermanni boettgeri, can be found in the approximately 180 km long adjoining coastal section to the hinterland of the Montenegrin Budva. In this relatively large mixing zone, intergrade, i.e. mixed subspecies, often occur.
The population density increases so strongly from the Montenegrin border that within a few days in May 2006 we were able to observe a total of six turtles crossing roads. Two other animals were run over on the side of the road.
South of Budva we only found turtles, which we could assign to the eastern subspecies mainly due to their size and the distinctive inguinals, but also due to the rest of their appearance.
Very many of the T. h. Found in Montenegro. boettgeri, were very dark animals. However, this is only astonishing at first, after all, it is about T. h. boettgeri in a northern distribution area.
During our excursion in May 2005, from Istria to the Neretva estuary, we inspected a total of 20 suspected turtle habitats and only found what we were looking for in 9 habitats in which we were able to catalog a total of 33 turtles. In May 2006 we examined 23 suspected habitats from the Neretva, including the valley to the Albanian border region. In 19 we were able to measure and photograph a total of 92 turtles. A total of 125 turtles were registered in 28 habitats on both excursions. Thereof in 11 habitats in the distribution area north of the Neretva, 10 between the Neretva and Budva and 7 between Budva and the Albanian border region. We were able to assign a total of 42 animals to the Dalmatian tortoise.
For the layman, the Dalmatian tortoise is difficult to distinguish from the other subspecies. The inguinal shields only help to a limited extent here, because these are not infrequently present on one or both sides in the Dalmatian tortoise. I have also found turtles of both the western and the eastern subspecies without any hip shields. The absence of these shields is, however, a first indication of a Dalmatian tortoise.
Our field research on these 42 Dalmatian tortoises from 11 habitats has shown that these shields were missing on both sides in 60% of the animals. They were unilateral in 14% and bilateral in 26% of the tortoises examined! 65% of the animals had a more or less pronounced keyhole mark on the 5th vertebral shield.
As you can see, the differentiation of the subspecies of the Greek tortoises from one another is not always easy and for inexperienced users only possible with animals with really well-known classic distinguishing features.
