On the Use of Tri-Stereo Pleiades Images for the Morphometric Measurement of Dolines in the Basaltic Plateau of Azrou (Middle Atlas, Morocco)

Hundreds of large and deep collapse dolines dot the surface of the Quaternary basaltic plateau of Azrou, in the Middle Atlas of Morocco. In the absence of detailed topographic maps, the morphometric study of such a large number of features requires the use of remote sensing techniques. We present the processing, extraction, and validation of depth measurements of 89 dolines using tri-stereo Pleiades images acquired in 2018–2019 (the European Space Agency (ESA) © CNES 2018, distributed by Airbus DS). Satellite image-derived DEMs were field-verified using traditional mapping techniques, which showed a very good agreement between field and remote sensing measures. The high resolution of these tri-stereo images allowed to automatically generate accurate morphometric datasets not only regarding the planimetric parameters of the dolines (diameters, contours, orientation of long axes), but also for what concerns their depth and altimetric profiles. Our study demonstrates the potential of using these types of images on rugged morphologies and for the measurement of steep depressions, where traditional remote sensing techniques may be hindered by shadow zones and blind portions. Tri-stereo images might also be suitable for the measurement of deep and steep depressions (skylights and collapses) on Martian and Lunar lava flows, suitable targets for future planetary cave exploration.

Description of a new Patagonian species of Urophonius Pocock (Scorpiones, Bothriuridae), from Meseta de Somuncurá, Argentina

Urophonius somuncura n. sp. (Scorpiones, Bothriuridae) is described and illustrated. This species is presumably endemic to the higher plains of the Meseta de Somuncurá (province of Río Negro, Argentina), a basaltic plateau in northern Patagonia. Its nearest relatives are U. granulatus Pocock, from southern Patagonia, and U. tregualemuensis Cekalovic, from central Chile, with all three belonging to the 'granulatus species group'. The diagnostic characters for the new species include the development of the ventral submedian carinae on metasomal segment I, the number of ventral setae on the same segment and presence of tegumentary borders around them, and details of the pigment pattern on carapace, mesosomal tergites and metasoma, among others. U. somuncura n. sp. is seemingly a species active in summer, and its activity period is probably slightly asynchronous in respect to a sympatric Bothriurus species.