A study of the paleoenvironmental evolution of the middle Eocene platforms recognized in the westernmost Tethys has been carried out in the well-exposed middle Eocene succession from Sierra Espuña-Mula basin (Betic Cordillera, S Spain). Eight microfacies (Mf1 to Mf8) have been recognized, based mainly on fossil assemblages (principally larger benthic foraminifera), and rock texture and fabric. The fossiliferous assemblage can be assigned to the ‘subtropical’ heterozoan association or to the low-latitude ‘foralgal facies’, which are dominated by non-framework building, light-dependent biota such as perforate larger benthic foraminifera, coralline algae, and sometimes green algae and solitary corals. Larger benthic foraminifer assemblages, corresponding from euphotic to oligophotic conditions and the large surface showed, suggest a progressive marine ramp under essentially oligotrophic conditions. Eventually, supply of detrital sediments from the continent and/or upwelling currents increases the nutrients of marine waters. Comparison with other Tethyan sectors allows stating that coral-reef buildups (z-corals) were widespread on shallow platforms of the central and eastern Tethys Ocean, but these were neither of great dimensions nor dominant because of the much more dominant presence of larger benthic foraminifera. Moreover, these coral constructions were completely absents in the westernmost Tethys. The dominance of larger benthic foraminifera and the absence of z-corals in the westernmost Tethys are explained by particular paleogeographic features due to the occurrence of a narrow and deep oceanic branch (i.e., the Maghrebian Flysch Basin) connecting the Tethys with the Atlantic Ocean. The various issues regarding the morphological characters and evolution of larger benthic foraminifera in the study area, such as sizes of tests, specific diversity and/or intraspecific variability, number of appearances and last occurrences during the middle Eocene are analyzed and compared with those appearing in other Tethyan sectors. In addition, the early to late Bartonian boundary is recognized in the study area as critical for the biological change as in other shallow-marine environments along the Tethys margins.

在特提斯山脉最西端公认的中新世中古平台古环境演化的研究，是在来自埃塞普纳-穆拉盆地（西班牙巴蒂科迪勒拉）的中新世中部演替阶段中进行的。八个微相（Mf1至Mf8）已被认可，主要基于化石组合（主要是较大的底栖有孔虫），岩石质地和织物。可以将化石组合归为“亚热带”杂居动物群或低纬度“藻类相”，它们主要由非框架结构，依赖光的生物群（例如较大的底栖有孔虫，珊瑚藻，有时是绿色的藻类）组成。藻类和孤立的珊瑚。较大的底栖有孔虫组合，对应于从富营养到贫光的条件，并且显示出较大的表面，这表明在基本上是富营养的条件下，海洋逐渐形成斜坡。最终，来自大陆的碎屑沉积物和/或上升流将增加海水的养分。与其他特提斯地区的比较表明，珊瑚礁堆积物（z-corals）广泛分布在特提斯海洋中部和东部的浅平台上，但是由于较大的底栖有孔虫的存在，它们既没有很大的尺寸也没有优势。 。而且，在最西端的特提斯完全没有这些珊瑚构造。在特提斯最西端，较大的底栖有孔虫占优势，并且没有z珊瑚，这是由于古特形的地理特征所致，这是由于将特提斯与大西洋连接在一起的是一个狭窄而深的海洋分支（即马格里比亚弗利希盆地）。有关研究区域较大底栖有孔虫的形态特征和演变的各种问题，例如试验的大小，分析了中始新世期间的特定多样性和/或种内变异性，出现次数和最后出现次数，并将其与其他特提斯地区的结果进行了比较。此外，与特提斯边缘的其他浅海环境一样，研究区域中早晚的巴顿边界对生物变化至关重要。