The Galapagos Islands (Ecuador) have a unique ecosystem on Earth due to their outstanding biodiversity and geological features. This also extends to their subterranean heritage, such as volcanic caves, with plenty of secondary mineral deposits, including coralloid-type speleothems and moonmilk deposits. In this study, the bacterial communities associated with speleothems from two lava tubes of Santa Cruz Island were investigated. Field emission scanning electron microscopy (FESEM) was carried out for the morphological characterization and detection of microbial features associated with moonmilk and coralloid speleothems from Bellavista and Royal Palm Caves. Microbial cells, especially filamentous bacteria in close association with extracellular polymeric substances (EPS), were abundant in both types of speleothems. Furthermore, reticulated filaments and Actinobacteria-like cells were observed by FESEM. The analysis of 16S rDNA revealed the presence of different bacterial phylotypes, many of them associated with the carbon, nitrogen, iron and sulfur cycles, and some others with pollutants. This study gives insights into subsurface microbial diversity of the Galapagos Islands and further shows the interest of the conservation of these subterranean geoheritage sites used as show caves.

Trichuris trichiura is a nematode considered as the whipworm present in humans and primates. The systematics of the genus Trichuris is complex. Morphological studies of Trichuris isolated from primates and humans conclude that the species infecting these hosts is the same. Furthermore, numerous molecular studies have been carried out so far to discriminate parasite species from humans and Non-Human Primates using molecular techniques, but these studies were not performed in combination with a parallel morphological study. The hypothesised existence of more species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other putative new species of whipworms. In the present work, a study of Trichuris Roederer, 1761 (Nematoda:Trichuridae) parasitizing C. g. kikuyensis, P. ursinus, Macaca sylvanus, Pan troglodytes, and Sus scrofa domestica has been carried out using modern morphometric techniques in order to differentiate populations of Trichuris isolated from four species of captive NHP from different geographical regions, and swine, respectively. The results obtained revealed strong support for geometrical morphometrics as a useful tool to differentiate male Trichuris populations. Therefore, morphometrics in combination with other techniques, such as molecular biology analyses, ought to be applied to further the differentiation of male populations. On the other hand, morphometrics applied to female Trichuris species does not seem to contribute new information as all the measurements combinations of obtained from females always showed similar results.

The Lascaux Cave in France is an old karstic channel where the running waters are collected in a pool and pumped to the exterior. It is well-known that water bodies in the vicinity of humans are suspected to be reservoirs of amoebae and associated bacteria. In fact, the free-living amoebae Acanthamoeba astronyxis, Acanthamoeba castellanii, Acanthamoeba sp. and Hartmannella vermiformis were identified in the sediments of the cave using phylogenetic analyses and morphological traits. Lascaux Cave sediments and rock walls are wet due to a relative humidity near saturation and water condensation, and this environment and the presence of abundant bacterial communities constitute an ideal habitat for amoebae. The data suggest the need to carry out a detailed survey on all the cave compartments in order to determine the relationship between amoebae and pathogenic bacteria.

Fleas (Siphonaptera) are one of the most important ectoparasites that represent a potential danger for the transmission of pathogens in our environment. The cat flea, Ctenocephalides felis (Bouché, 1835), and the dog flea, Ctenocephalides canis (Curtis, 1826) are among the most prevalent and most frequently studied species throughout the world. However, the variations observed in their morphological characteristics complicate their correct identification, especially when there is a lack of access to the equipment and funds required to carry out molecular biology techniques. With the objective to provide an additional tool to help in the differentiation of Ctenocephalides species, a principal component analysis was carried out for the first time in the present work on populations of C. felis and C. canis from countries in three continents, namely Spain (Europe), South Africa (Africa) and Iran (Asia). The factor maps assisted in the differentiation of both species and the detection of differences in overall size, although morphological ambiguity prevented the delimitation in populations of the same species. Thus, morphometrics represents a complementary tool to other traditional and modern techniques, with great potential to assist in the differentiation of fleas, particularly species that have historically been difficult to identify.