Distribución y uso del hábitat de los reptiles en las Bardenas Reales de Navarra y su entorno

Desde 2012 hasta 2021 se recopilaron un total de 435 observaciones de reptiles en la Zona Especial de Conservación de las Bardenas Reales (Navarra) y su entorno, correspondientes a quince especies autóctonas. Las observaciones fueron cartografiadas en cuadrículas UTM de 5 x 5 km, que permitieron actualizar la distribución de estas especies en la zona. Su patrón de presencia puede resumirse en tres tipos de ocupación espacial: especies ubiquistas, especies de distribución puntual en ambientes selectivos y especies concentradas en zonas restringidas y concretas. El matorral mediterráneo es el hábitat que presenta el mayor número de observaciones (63 % de los registros). La especie de saurio más ampliamente representada fue Psammodromus algirus (Linnaeus, 1758) (73,81 % de las cuadrículas), y la de ofidio, Natrix maura (Linnaeus, 1758) (38,10 %). Emys orbicularis (Linnaeus, 1758), favorecida por un programa de seguimiento poblacional y mejora de su hábitat, fue localizada en el 16,67 % de las cuadrículas. Las especies más escasas fueron Chalcides bedriagai (Boscá, 1880) (2,38 %) y Vipera latastei Boscá, 1878 (9,52 %)

Data on the body temperature of some ophidians in the Southeast of the Iberian Peninsula

La biología térmica es uno de los aspectos más necesarios para entender la distribución y los patrones de actividad de las especies, sobretodo de los organismos ectotermos. El presente estudio aporta información sobre temperatura corporal de seis ofidios ibéricos y temperatura ambiental para el lugar donde habitan. Para tres de las especies, Coronella girondica (Daudin 1803), Macroprotodon brevis (Günter 1862) y Hemorrhois hip­pocrepis (Linnaeus 1758), estos son los primeros datos publicados en España. En el caso de Natrix maura (Linnaeus 1758) los datos de este estudio incluyen temperatura tanto en medio acuático como en medio terrestre. En total se han obtenido 31 registros de temperatura corporal y 30 registros de temperatura ambiente. También se aportan datos sobre temperatura corporal y ambiental de Malpolon monspessulanus (Hermann 1804) y Zamenis scalaris (Schinz 1822). Thermal biology is one of the most necessary aspects in understanding the distribution and activity patterns of species, above all of ectothermal organisms. The present study provides data on body temperature of six Iberian ophidians and the environmental temperature of the place they inhabit. For three species, southern smooth snake Coronella girondica (Daudin 1803), western false smooth snake Macroprotodon brevis (Günter 1862), and horse-shoe snake Hemorrhois hippocrepis (Linnaeus 1758), these are the first data published in Spain. In the case of Natrix maura (Linnaeus 1758), the present data include its temperature on land as well as in aquatic environments. In total, 31 body temperature records and 30 ambient temperature records were obtained. Additionally, data is given on body and environmental temperature for the ophidian species Malpolon monspessulanus (Hermann 1804) and Zamenis scalaris (Schinz 1822).

Axial Bifurcation and Duplication in Snakes. Part VIII. Specimens Deposited in or Affiliated with the Natural History Museum of Paris (MNHN)

A review of the dicephalic (two-headed) snakes in the Natural History Museum of Paris (MNHN) reveals that 16 specimens have been present or catalogued into the various collections (MHNH-RA, MNHN-AC, and Teratological Collection) over the years. Only seven specimens have been located in the collections but some of the nine missing specimens may be present but not yet found. The 16 MNHN specimens are described based on available information. More details are provided for the seven extant specimens in the collections, including photographs, radiographs, and the first description of the internal anatomy of dicephalic Elaphe schrenckii, Natrix maura, and Montivipera xanthina.

High temperatures limit developmental resilience to high-elevation hypoxia in the snake Natrix maura (Squamata: Colubridae)

Climate change is generating range shifts in many organisms, notably along the altitudinal gradient. However, moving up in altitude exposes organisms to lower oxygen availability, which may negatively affect development and fitness, especially at high temperatures. To test this possibility in a potentially upward-colonizing species, we artificially incubated developing embryos of the viperine snake Natrix maura Linnaeus 1758, using a split-clutch design, in conditions of extreme high elevation or low elevation at two ecologically-relevant incubation temperatures (24 and 32 °C). Embryos at low and extreme high elevations incubated at cool temperatures did not differ in development time, hatchling phenotype or locomotor performance. However, at the warmer incubation temperature and at extreme high elevation, hatching success was reduced. Further, embryonic heart rates were lower, incubation duration longer and juveniles born smaller. Nonetheless, snakes in this treatment were faster swimmers than siblings in other treatment groups, suggesting a developmental trade-off between size and performance. Constraints on development may be offset by the maintenance of important performance metrics, thus suggesting that early life-history stages will not prevent the successful colonization of high-elevation habitat even under the dual limitations of reduced oxygen and increased temperature.

Antipredatory behaviour of a mountain lizard towards the chemical cues of its predatory snakes

The ability to early detect a potential predator is essential for survival. The potential of Iberolacerta cyreni lizards to discriminate between chemical cues of their two predatory snakes Coronella austriaca (a non-venomous active-hunter saurophagous specialist) and Vipera latastei (a venomous sit-and-wait generalist) was evaluated herein. A third snake species, Natrix maura, which does not prey on lizards, was used as a pungent control. Thus, the behaviour of I. cyreni was studied regarding four treatments: (1) C. austriaca scent, (2) V. latastei scent, (3) N. maura scent and (4) odourless control. Lizards showed antipredator behaviour (such as slow-motion and tail waving) to C. austriaca and V. latastei chemicals. The antipredatory response was similar for both predators. This ability to react with an intensive behavioural pattern to the chemical cues of their predatory snakes may prevent lizards from being detected, and, if detected, dissuade the predator from beginning a pursuit.