Artificial light at night and captivity induces differential effects on leukocyte profile, body condition, and erythrocyte size of a diurnal toad.

Light pollution or artificial lighting at night (ALAN) is an emerging threat to biodiversity that can disrupt physiological processes and behaviors. Because ALAN stressful effects are little studied in diurnal amphibian species, we investigated if chronic ALAN exposure affects the leukocyte profile, body condition, and blood cell sizes of a diurnal toad. We hand-captured male toads of Melanophryniscus rubriventris in Angosto de Jaire (Jujuy, Argentina). We prepared blood smears from three groups of toads: "field" (toads processed in the field immediately after capture), "natural light" (toads kept in the laboratory under captivity with natural photoperiod), and "constant light" (toads kept in the laboratory under captivity with constant photoperiod/ALAN). We significantly observed higher neutrophil proportions and neutrophils to lymphocytes ratio in toads under constant light treatment. In addition, we observed significantly better body condition and higher erythrocyte size in field toads compared with captive toads. In summary, ALAN can trigger a leukocyte response to stress in males of the diurnal toad M. rubriventris. In addition, captivity can affect the body condition and erythrocyte size of these toads.

Variation of thermal parameters in two different color morphs of a diurnal poison toad, Melanophryniscus rubriventris (Anura: Bufonidae).

We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization. The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of color pattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines.

A new species of Elachistocleis (Anura: Microhylidae) from north-western Argentina.

Elachistocleis haroi sp. nov. is described from El Algarrobal, Jujuy province, north-western Argentina. The new species is diagnosed by the dorsal pattern of mid-longitudinal bright yellow stripe from the intraocular zone, surpassing the post-cephalic transverse skin fold, to vent; dorsum grayish brown mottled with a paravertebral symmetric pattern of dark spots resembling a pine tree; and a thin regular yellow line on the posterior surface of the thighs and tibiae. The advertisement call is a long trill with an average duration of 3.18 seconds, multipulsed with a mean dominant frequency of 4.56 kHz. The tadpole is characterized by the oral dermal flaps with papillae-like edges.