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  • Author or Editor: Valentín Pérez-Mellado x
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Abstract

The taconomic status of Podarcis bocagei in the Iberian Peninsula is reviewed. Since no Holotype is known, a Lectotype from the species is given. P. bocagei carbonelli ssp. n. is also described; it inhabits the western area of the Sistema Central, in particular the "Sierras" of Francia and Gata, both in Spain and the Serra da Estrela in Portugal. Finally, new localities for both subspecies are described, that together with those reported in the previous paper sum a total of 76 localities known up to date.

In: Amphibia-Reptilia

Abstract

P. bocagei is considered a valid species, and several criteria are used for distinguish it in sympatry of P. hispanica, a closely related species. A detailed distribution map is provided for this lizard, which occurs in Galicia, León, Orense, Zamora, western slopes of the Sistema Central, and probably, the north of Portugal. P. hispanica males and females in the Sistema Central are significant larger than males and females of P. bocagei. Significant differences in size, scalation and ecology are apparent between the Sistema Central and northern populations of P. bocagei, but no taxonomic decisions are made, pending a more detailed study. The examination of the masseteric shield revealed its large size in P. bocagei and its absence in most of the P. hispanica studied. P. bocagei has a relatively robust, deep skull, probably related to his terrestriral habits, unlike P. hispanica, which has a flattened skull and, at least in the Sistema Central, is a saxicolous species. P. bocagei is very common in Galicia and is found there at altitudes between 0 and 1500 meters, but in the Sistema Central is restricted to Quercus pyrenaica forests, between 800 and 1200 meters.

In: Amphibia-Reptilia
In: Amphibia-Reptilia

Abstract

The behavioral thermoregulation of P. pityusensis was studied for a period of one week during August, 1980. The cloacal temperatures and the ground and air temperatures were recorded by means of thermistors. P. pityusensis behaves like a heliotermic species with a temperature range between 28.5 and 41.5 ° C. Very significant correlations were found to exist between the Tc (Body temperatures) and the Ta (Air temperatures) or between the Tc and the Ts (Ground temperatures) in all ofthe specimens analyzed. There are also significant statistical differences between te mean Tc in individuals during thermoregulation and the Tc of individuals active on the ground or inactive underneath stones. The daily pattern of activity is bimodal; the variations in body temperatures, being as a whole relatively independent of the fluctuations in the ambient temperature, adjust themselves to this pattern. P. pityusensis, roughly speaking, manifest several characteristics of the behavioral thermoregulation and pattern of activity similar to those described for other lizards such as Psammodromos algirus, inhabitants of the mediterranean region which is characterized by its hot, dry summers.

In: Amphibia-Reptilia

Abstract

The Majorcan Midwife Toad (Alytes muletensis) is and endemic and threatened species of the island of Mallorca which has been the subject of a large number of studies. However, there is a lack of information about the adult fraction of wild populations. Here we show the first step to increase the knowledge of adult Majorcan midwife toads, how to recognize them individually and how to distinguish between males and females. We tested with satisfactory results a photoidentification method that can be used to identify adults individually. In order to sex individuals in the wild we carry out a morphological study with fourteen variables building a discriminant function which allow us to sex all captured adults.

In: Amphibia-Reptilia

We studied the thermal ecology of Testudo hermanni hermanni in Menorca during late spring. We measured body temperatures of adult individuals, together with air and substrate temperatures at points of capture. Sunlight exposure (full sun, filtered sun, or shade) and type of substrate were also recorded. Body temperatures were similar between sexes (mean = 29.95°C) as were air temperatures between gender capture sites (mean = 28.33°C). Conversely, females were found in areas with a higher substrate temperature (31.60°C) than males were (29.15°C). Moreover, the correlation between body and air temperatures was stronger than it was between body and substrate temperatures, as found in other populations of this species. The tortoises were usually found in full sun, and the proportion of animals found in each sunlight category was similar between sexes. Our results contribute to the knowledge of the thermal ecology of the western Hermann’s tortoise.

In: Amphibia-Reptilia
In: Amphibia-Reptilia

Individual time budgets under natural conditions and under increased population density conditions were studied in a population of Podarcis hispanica inWestern Spain. We examined the effects of sex, time of day, and density on daily time budgets. Artificially increasing density indicated that demographic changes do affect time budgets, and that the animals initially respond with short-term compensatory behavior. We found that: (1) basking was the predominant behavior in time budgets of all lizards; (2) thermoregulatory patterns are affected by high population density; (3) our results confirm the hypothesis that density of population, and not sex, is a primary factor affecting basking behavior, i.e., high population density leads to increased basking; (4) social interaction frequency increased and percentage of time resting decreased at high population density.

In: Israel Journal of Ecology and Evolution

Lizards and gulls cohabit in several Mediterranean islands. The yellow-legged gull, Larus michahellis, was found to prey several vertebrate species. However, precise information about the interaction between gulls and other vertebrates, particularly with lizards is still scarce. The Balearic lizard, Podarcis lilfordi, shares several coastal islets with the yellow-legged gull. Using two different sources of information, we studied the interaction of both species in Colom Island (Menorca, Balearic Islands, Spain). We studied the diet of the yellow-legged gull and learnt that the Balearic lizard is not a common prey of the yellow-legged gull. On the other hand, we studied the potential predation pressure of gulls on lizards, using plasticine models of lizards. We did two different experiments from which we can conclude that yellow-legged gulls rarely attack lizards and, consequently, cannot be considered a major threat for this endemic lizard species, at least in the population under study. Finally, we obtained evidence that plasticine models can only be employed with caution to assess predation pressure of opportunistic scavengers, much as gulls are. The majority of marks on models were not the consequence of true attacks by gulls, but the result of ground exploratory behaviour of gulls in search of any edible matter. Therefore, contrary to popular belief, in the case of the yellow-legged gull, the proportion of marked models would be an indication of ground-based wandering activity, rather than a result of its predation pressure on lizards.

In: Amphibia-Reptilia