The metabolic cost of turning right side up in the Mediterranean spur-thighed tortoise (Testudo graeca)

Armoured, rigid bodied animals, such as Testudines, must self-right should they find themselves in an inverted position. The ability to self-right is an essential biomechanical and physiological process that influences survival and ultimately fitness. Traits that enhance righting ability may consequently offer an evolutionary advantage. However, the energetic requirements of self-righting are unknown. Using respirometry and kinematic video analysis, we examined the metabolic cost of self-righting in the terrestrial Mediterranean spur-thighed tortoise and compared this to the metabolic cost of locomotion at a moderate, easily sustainable speed. We found that self-righting is, relatively, metabolically expensive and costs around two times the mass-specific power required to walk. Rapid movements of the limbs and head facilitate successful righting however, combined with the constraints of breathing whilst upside down, contribute a significant metabolic cost. Consequently, in the wild, these animals should favour environments or behaviours where the risk of becoming inverted is reduced.

Thyroid hormone levels in Tortoises (Testudo spp.) depending on Season and Sex

Thyroid hormones and the factors influencing them are rarely studied in tortoises. This study therefore aimed to calculate reference intervals (RI) for specific species, sexes, and seasons for thyroid hormones and iodine levels in blood of four adult Mediterranean tortoise species and to evaluate possible correlations between thyroid hormones, serum iodine, plasma protein and increased liver and kidney values. Thyroid hormones (total tetraiodothyronine [tT4], free tetraiodothyronine [fT4], total triiodothyronine [tT3], and free triiodothyronine [fT3]) were measured in plasma from adult, healthy Hermann´s (Testudo hermanni, n = 255), spur-thighed (Testudo graeca, n = 89), marginated (Testudo marginata, n = 72), and Russian tortoises (Testudo horsfieldii, n = 30). Species, sex and season specific variations were determined by Bayesian information criterion (BIC) and correlations between plasma thyroid hormones, protein, iodine and increased liver/kidney values were evaluated by Spearman’s rank correlation test. Total T4 did not reveal any species, sex, or seasonal differences (RI 0.102 to 0.455 µg/dL), while seasonal differences were found for fT4 (RI spring 0.624 to 9.012; summer 0.379 to 5.476; fall 0.376 to 5.426 pmol/L). The tT3 levels differed significantly depending on species, season, and the interaction of species x season. Seasonal differences were also found for fT3 and iodine. Several significant (p < 0.05) correlations were detected between the tested analytes, especially positive correlations between tT4 and fT4. These results provide a tool for the evaluation of thyroid hormone levels in Mediterranean tortoises and indicate the influence of season on the thyroid in these animals.

“Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum”: A response to Turkozan et al. (2021)

Species distribution models (SDMs) are frequently used to characterise current, past or future realised environmental niches. Two recent studies applied different approaches to infer range dynamics in eastern subspecies of the spur-thighed tortoise Testudo graeca Linnaeus, 1758. We discuss differences in the conclusions of the two papers and use multivariate environmental similarity surface (MESS) analyses to show that the results of the study by Turkozan et al. (2021), recently published in the Herpetological Journal, are compromised by extrapolation and therefore have to be interpreted with caution.

First detection of herpesvirus and mycoplasma in free-ranging Hermann’s tortoises (Testudo hermanni), and in potential pet vectors

Two types of pathogens cause highly contagious upper respiratory tract diseases (URTD) in Chelonians: testudinid herpesviruses (TeHV) and a mycoplasma (Mycoplasma agassizii). In captivity, these infections are frequent and can provoke outbreaks. Pet trade generates international flow of tortoises, often without sanitary checking; individuals intentionally or accidentally released in the wild may spread pathogens. A better understanding of the transmission of infectious agents from captivity to wild tortoises is needed. Many exotic individuals have been introduced in populations of the endangered western Hermann’s tortoise (Testudo hermanni hermanni), notably spur-thighed tortoises (Testudo graeca). We assessed the presence of TeHV and mycoplasma in native western Hermann’s tortoises and in potential pet vectors in south-eastern France. Using a large sample (N=572 tortoises), this study revealed the worrying presence of herpesvirus in 7 free-ranging individuals (3 sub-populations). Additionally, Mycoplasma agassizii was detected in 15 of the 18 populations sampled with a frequency ranging from 2.5 to 25%. Exotic spur-thighed tortoises showed high frequency of Mycoplasma infection in captivity (18%) and in individuals (50%) found in native Hermann’s tortoise sub-populations, suggesting that this species could be a significant vector. The paucity of information of TeHV on European tortoise’ URTD in natural settings, especially in combination with mycoplasma, prompts for further studies. Indeed, sick tortoises remain concealed and may not be easily detected in the field. Our results indicate that both the prevalence and health impact of URTD are high should be scrutinized in the field.

Prevalence and intensity of gastrointestinal parasites in the vulnerable spur-thighed tortoise (Testudo graeca) from the central-western of Morocco

This study was undertaken to determine the prevalence and intensity of gastrointestinal parasites in wild Testudo graeca tortoises in Morocco. A total of 102 tortoises sampled in two arid areas: Central Jbilets Mountains (CJM) and Sidi Kaouki Forest (SKF) were macroscopically examined and subjected to qualitative (flotation and Baermann techniques) and quantitative (McMaster technique) microscopic examinations. The identified gastrointestinal parasites belong to two nematode families (Pharyngodonidae and Ascarididae) and three protozoa families (Balantidiidae, Eimeriidae and Entamoebidae). 92.1% of tortoises were determined to harbor one or more parasite types. Oxyurid adults were the most frequently encountered with a prevalence of 22.7% and 72.4% in CJM and SKF, respectively. Nematode eggs were found in almost all individuals of both populations studied. The prevalence of protozoa was 9.1% and 3.4% in CJM and SKF, respectively. Oxyurid adults showed the highest intensity in SKF (36.5 ± 30.2) whereas, ascarid adults are absent in CJM. Statistical analysis showed that the prevalence of infection by ascarids was significantly higher in adults than in juveniles. The intensity of infection by ascarid and oxyurid eggs differed significantly between sexes and localities, respectively. Our results showed a difference of infection between the two localities, which could be in relation with habitat quality. SKF is affected by both agriculture and overgrazing. In addition, the tortoises from this locality are active for a large part of the year, which increases their chance of encountering the parasites.

Review of the herpetofauna of Attica, mainland Greece

Although the insular distribution of the rich herpetofauna of Greece has been studied more extensively, the mainland one is still underexplored. The region of Attica in central Greece represents one of these “black spots” in the mainland. Thus, in 2019 we surveyed for the first time the herpetofauna of Attica in a systematic way. We collected 794 field records of 31 species (4 amphibians, 27 reptiles); Testudo graeca and Trachemys elegans were documented for the first time for Attica.

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.