Hybrids - Testudoalbino

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Hybrids

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Testudo hermanni Testudo marginata Testudo graeca Color variants Hybrids

Species and subspecies hybrids

As everybody knows, hybrids of testudo graeca and testudo marginata are not uncommon: babies resulting from these crossbreedings are thriving, grow vigorously and are, in turn, very fertile. However, I have never found scientific studies dealing with this issue. Cross-breeding between different species is often associated with new speciation and this is not necessarily a bad thing. Human race itself is the result of hybridizations between different Homo species, but it cannot be excluded that these crossbreedings have occured throughout man’s history. Usually, a sterile hybrid appears for various reasons: first of all, it may be that a different karyotype, in the meiosis phase, hindered gametogenesis. In other cases, fertility is greatly reduced, or only one of the two sexes preserves it. In any case, this enables us to understand more deeply certain biological mechanisms: hybridization surely strengthens the animal when the conditions are adequate for it to occur.

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Testudo graeca ibera x Testudo marginata F1

Hybrids of Testudo graeca ibera x Testudo marginata

This sheet will be updated over the years, and probably will not be definitively completed within a decade.
At the beginning of the 2000s, I put a young Testudo graeca Iberia female, born in 1994, in the male group of albino CARAMEL Testudo marginata specimens. They were not interested in mating and the female’s eggs were not fertile. This fact could bear several meanings: either I did not notice the mating or hybridization was not possible or embryos could not develop. Actually, Tm males were not interested in the newcomer. I therefore used artificial insemination and immediately I obtained a few hatchings. First of all, what characterizes a testudo graeca and marginata’s hybrid is the absolute absence of colors and pattern on the plastron, while the other traits, at least in F1, are often intermediate to the two species. In particular, Tg shape and size are dominant, while the absence of tubercles along the tail and the shape of the nose are riminiscent of Tm.

8 years after the birth of these specimens, I observe that they have vigorously developed and the larger females’ carapace have already reached 24 cm in length, while males’ seem to have stopped at 18-20 cm. This is a difference that get the hybrid more closer to testudo graeca since the Testudo marginata males’ size is usually similar to females’.

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Testudo graeca ibera x Testudo marginata F2

Hybrid x Hybrid

In June 2015, I observed the first laying of a hybrid specimen, but of ten eggs only two appeared to be fertile, although they did not further develop. In 2016 another female laid 10 and 7 eggs for the first time within approximately three weeks. It soon became apparent that only a couple of eggs per laying had begun to develop. Given the very young age of the specimens, which were born in 2008, this fact did not surprise me at all. In the upcoming years the situation will become clearer and we will be able to draw the first, meaningful conclusions.

However, one egg of the first laying hatched regularly with a timing close to testudo graeca’s, i.e. approximately 10 days longer compared to Testudo marginata under equal incubation conditions, although showing evident malformations, which jeopardized its survival. The baby was still alive at the beginning of 2016/2017 hibernation. Darker phenotype and similar to Testudo marginata’s, colorless plastron.

As to second laying, unfortunately the only embryo come to term died because of a reversal within the egg that suffocated it. Apparently perfect, the embryo presumably died two or three days before the hatching, considering the amount of yolk present. It had an albino phenotype. This shows without any reasonable doubt that hybridization has actually occurred and that the mutated gene in Tm can be expressed in the same way as the F2 hybrid is expressed. The 2017 season will certainly tell us more about it.