Andrea Corral-Lou

Marine sponges (phylum Porifera) are a highly diverse and polymorphic group of marine invertebrates whose taxonomic delimitation is often challenging due to high intraspecific variability and the scarcity of diagnostic morphological characters. Their close association with microbial symbionts also makes them an important source of secondary metabolites, some of which may contribute to sponge colouration. Here, we use morphological characters, molecular phylogenetic markers, and 16S metabarcoding of the symbiont community to understand speciation in a common Mediterranean sponge lineage. We collected 43 specimens of the genus Suberites from the Mediterranean Sea and the North and South Atlantic Oceans, between 55-150 m depths, and sequenced two barcoding genes, cytochrome c oxidase I and 28S rDNA, as well as studied their spicular complements. We identified five closely-related species: S. domuncula , S. ficus/pagurorum , S. dandelenae , S. ambulodomus , and a new species of Suberites from the Balearic Islands, Suberites sp. nov. The latter represents a potential new pseudo-cryptic species closely related to S. domuncula , because of their strong morphological and molecular affinities. The potential new Mediterranean species exhibits six colour morphotypes (yellow, gray, orange, brown, red, and blue), and the microbiome analyses of the symbiotic communities revealed significant differences in bacterial community composition among colour morphotypes, specially of bacteria that produce different pigments which potentially give the sponge is colouration. These results provide valuable insights into species boundaries and evolutionary relationships within the genus Suberites and support a role for the microbiome in sponge colouration.

Ecosystem monitoring is a fundamental tool to avert biodiversity loss, gathering valuable information that can be used to develop conservation policies, evaluate management outcomes, and guide science‐based decision‐making. The Mar Menor coastal lagoon (South‐East of Spain) has experienced episodes of eutrophication due to intensive agriculture and other human activities, causing mass mortalities of marine fauna. In this scenario, biodiversity monitoring is crucial to evaluate the status of fauna and flora and take appropriate measures. Here, our main objective was to assess faunal composition and its spatial and temporal structure associated with the pillars used to support the built recreational well‐being facilities along the Mar Menor. We capitalized on the many sea sponges that settle on these structures by collecting tissue samples for subsequent extraction of filtered environmental DNA (i.e., ‘natural sampler DNA’, nsDNA) in northern and southern areas of the lagoon, both in spring and summer. We metabarcoded all samples at the cytochrome oxidase subunit I gene (COI), and reliably identified 76 taxa belonging to nine different phyla, with annelids, poriferans, mollusks and cnidarians being the richest groups. We detected emblematic species of threatened status, such as pipefishes (genus Syngnathus) and the piddock clam, Pholas dactylus, and others known to become invasive, such as the ascidians Styela canopus and Botrylloides niger, the barnacle Amphibalanus amphitrite, and the polychaetes Branchiomma bairdi and Branchiomma boholense. The use of common and widely distributed sponges as natural eDNA samplers allowed us to characterize both spatial and temporal diversity, further emphasizing the importance of this low‐cost approach to monitoring biological communities in shallow coastal ecosystems.

Ecosystem monitoring is a fundamental tool to avert biodiversity loss, gathering valuable information that can be used to develop conservation policies, evaluating management outcomes, and guiding science-based decision-making. The Mar Menor costal lagoon (South-East of Spain) has experienced episodes of eutrophication due to intensive agriculture and other human activities, causing mass mortalities of marine fauna. In this scenario, biodiversity monitoring is crucial to evaluate the status of fauna and flora and take appropriate measures. Here, our main objective was to assess faunal composition and its spatial and temporal structure associated with the pillars used to support the built recreational well-being facilities along the Mar Menor. We capitalised on the many sea sponges that settle on these structures by collecting tissue samples for subsequent extraction of filtered environmental DNA (i.e. ‘natural sampler DNA’, nsDNA) in northern and southern areas of the lagoon, both in spring and summer. We metabarcoded all samples at the cytochrome oxidase subunit I gene ( COI ), and reliably identified 76 taxa belonging to nine different phyla, with annelids, poriferans, molluscs and cnidarians being the richest groups. We detected emblematic species of threatened status, such as pipefishes (genus Syngnathus ) and the piddock clam, Pholas dactylus , and others known to become invasive, such as the ascidians Styela canopus and Botrylloides niger , the barnacle Amphibalanus amphitrite , and the polychaetes Branchiomma bairdi and Branchiomma boholense . The use of common and widely distributed sponges as natural eDNA samplers allowed us to characterise both spatial and temporal diversity, further emphasizing the importance of this low-cost approach to monitoring biological communities in shallow coastal ecosystems.

We studied the population genetic structure of Cobitis vettonica, an endangered freshwater fish species endemic to the Iberian Peninsula, in order to propose a biogeographic model of the responses of species to the multiple changes that occurred in the Iberian hydrological system during the Quaternary period. We also deciphered the relationship of C. vettonica with its sister species C. paludica, particularly in sympatric areas, and provide genetic information for conservation purposes. To achieve this goal, we analyzed both mitochondrial and nuclear data (the cytochrome b and the nuclear recombination activating 1 genes) and a battery of single‐nucleotide polymorphisms (SNPs) of 248 individuals of C. vettonica or C. paludica from 38 localities, including some sympatric ones, covering the entire distribution area of C. vettonica. We highlight the important role played by the hydrogeomorphological processes and climatic changes that occurred in the Iberian Peninsula during the Quaternary on both the population structure of C. vettonica and its relationship with its sister species C. paludica. Our results support the genetic introgression of populations at the eastern limit of the distribution of C. vettonica. Furthermore, we postulate genetic introgression in sympatric areas. Finally, we propose the establishment or expansion of four Operational Conservation Units (OCUs) for C. vettonica, and highlight the threat faced by its populations due to the low level of genetic diversity detected for some of its populations and genetic introgression with C. paludica, which could eventually displace C. vettonica, resulting in a loss of diversity in this species.

We studied the population genetic structure of Cobitis vettonica, an endangered freshwater fish species endemic to the Iberian Peninsula in order to propose a biogeographic model of the responses of species to the multiple changes that occurred in the Iberian hydrological system during the Quaternary period. We also deciphered the relationship of C. vettonica with its sister species C. paludica, particularly in sympatric areas and provide genetic information for conservation purposes. To achieve this end, we analysed both mitochondrial and nuclear data (the cytochrome b and the nuclear recombination activating 1 genes) and a battery of single nucleotide polymorphisms (SNPs) of 248 individuals of C. vettonica or C. paludica from 38 localities, including some sympatric ones, covering the entire distribution area of C. vettonica. We highlight the important role played by the hydrogeomorphological processes and climatic changes that occurred in the Iberian Peninsula during the Quaternary on both the population structure of C. vettonica and its relationship with its sister species C. paludica. Our results support the genetic introgression of populations at the eastern limit of the distribution of C. vettonica. Furthermore, we postulate genetic introgression in sympatric areas. Finally, we propose the establishment or expansion of four OCUs for C. vettonica, and highlight the threat faced by its populations due to the low level of genetic diversity detected for some of its populations and genetic introgression with C. paludica, which could eventually displace C. vettonica, resulting in a loss of diversity in this species.

The genus Phoxinus is comprised of at least 15 currently recognized species inhabiting Eurasia. Morphological traits have been traditionally used to delineate species in Phoxinus; however, the high level of phenotypic plasticity observed in the genus has confounded this process. Molecular genetic analyses have revealed a higher than expected genetic structure within Phoxinus. Here, we analyzed both nuclear and mitochondrial molecular genetic markers to infer the phylogeography and divergence times of Phoxinus in the Iberian Peninsula. Our results show that the Iberian lineages of Phoxinus were polyphyletic. They also support the co-existence of three species in the Iberian Peninsula, two corresponding to two previously recognized species (Phoxinus bigerri and Phoxinus septimaniae) and a third undescribed species (Phoxinus sp.). Phoxinus bigerri is structured into western Cantabrian, eastern Cantabrian, and Artibai basins. We hypothesize that this structure is a consequence of glaciation–deglaciation cycles during the Pleistocene. While the presence of P. septimaniae in the Iberian Peninsula is possibly the result of human translocation, that of Phoxinus sp. in lower Ebro rivers may be attributed to past fluvial captures. Our study represents the first report to show a relationship among Phoxinus populations from central Pyrenean rivers of Spain and France. Furthermore, we found genetic hybridization between Phoxinus sp. and P. septimaniae in the shared localities, a likely consequence of anthropogenic activities. Overall, our findings provide insight into the genetic structure of Iberian Phoxinus populations, including the presence of an undescribed species and the putative introduction of some species that may have implications for conservation.