Biology subjects

Matabos, M.

Publications and source records attributed to Matabos, M..

4 recordsLinked to original sources

bioRxiv2026

Two new gastropod holobionts from Atlantic hydrothermal vents showing different levels of endosymbiosis dependence

Chemosynthetic symbioses underpin animal life at deep-sea hydrothermal vents, encompassing substantial variabilities in symbiont identity, metabolic capacity, and host dependence. Here, we characterise symbioses in two peltospirid snails from Mid-Atlantic Ridge vents, Peltospira gargantua and P. smaragdina, using 3D anatomical reconstruction, stable isotope analyses, fluorescence in situ hybridization, transmission electron microscopy, and metagenomics. Both species hosted abundant intracellular Campylobacterota within bacteriocytes of a hypertrophied oesophageal gland. Their dominant symbionts belonged to genus Sulfurimonas, but the two hosts were associated with distinct symbiont lineages. Symbiont genomes encoded carbon fixation through the rTCA cycle, sulfide oxidation, and Group I Ni-Fe hydrogenases, indicating combined thiotrophic and hydrogenotrophic capacities. Hydrogenase copy number varied across vent fields from one to three copies. The P. gargantua symbiont from the hydrogen-enriched Hydra vent field carried two divergent copies, including one with a truncated catalytic region, potentially reflecting local adaptation to vent geochemistry. Anatomical and isotopic comparisons further revealed contrasting host dependence, with P. gargantua having a proportionally larger oesophageal gland and ventricle coupled with a reduced radula, as well as a greater nitrogen-isotope enrichment between symbiotic and non-symbiotic tissues. The smaller oesophageal gland and larger feeding apparatus of P. smaragdina point to it being mixotrophic. Previously, all known peltospirid symbioses have partnered with Gammaproteobacteria, and we expand the known diversity of peltospirid symbioses. Our findings underscore how closely related hosts can exhibit different degrees of dependence on symbiosis, and that mixotrophic symbiosis may be prevalent in small vent species previously thought to be non-symbiotic.

ecology↗

bioRxiv2026

High gene flow in Atlantic vent shrimp species with multiple ridge colonizations by ecotypic lineages with contrasting symbioses

Conservation concerns regarding potential mineral extraction near deep-sea hydrothermal vents have emphasised the need for a better understanding of the contemporary connectivity of various vent-endemic species, accounting for the specifics of their life-history traits and habitat requirements. Rimicaris shrimps are a major component of vent communities in the Atlantic Ocean, both along the Mid-Atlantic Ridge (MAR) and at the Mid-Cayman Spreading Center (MCSC). Using ddRAD sequencing, we examined the genetic differentiation of three Atlantic Rimicaris species to better understand their past and present migration pathways and the possible demographic history that led to their current distribution and ecology. Rimicaris exoculata and R. chacei inhabit the MAR and exhibit widespread gene flow along the ridge with no areas of restricted connectivity. R. hybisae occurs at the MCSC and exhibits almost no genetic difference with its congeneric from the MAR, R. chacei, despite the geographic distance between them and their contrasting ecologies and morphologies. Demographic inferences support a scenario of a very recent (less than 2000 generations) separation between MCSC and MAR shrimp populations, followed by a rapid expansion in both regions, possibly triggered by symbiotic development. Analyses further suggest recent or ongoing secondary contacts involving two-way migration, which is more pronounced from the MCSC towards the MAR. All together these results suggest that R. chacei and R. hybisae represent distinct forms of the same species, which we hereby synonymise as R. chacei, highlighting their morphological plasticity in relation to symbiosis.

evolutionary biology↗

bioRxiv2025

Peripheral tissues of deep-sea mussels exhibit autonomous circadian timing via an atypical mechanism

While biological rhythms are crucial to life, the deep sea has long been considered an arrhythmic exception. However, at hydrothermal vents - devoid of diel cues yet shaped by tides - the mussel Bathymodiolus azoricus shows both tidal and, unexpectedly, circadian rhythms at -1700 m. Whether endogenous clock(s) drive these cycles remained unanswered. Here, we report endogenous circadian rhythms in B. azoricus cell cultures under constant conditions: isolated cells displayed a circadian oscillator despite tidal-dominant rhythms in situ. Reporter assays using genomic regions upstream of the mussels per gene and containing E-box motifs indicate that a functional transcription-translation feedback loop (TTFL) underpins circadian timing even in the deep sea. In contrast to conventional models, however, BazPeriod lacks autonomous repressive activity but modulates BazCry2. As BazPeriod itself oscillates tidally, it may explain how a single endogenous clock yields both tidal and diel rhythms. The work also spotlights the highly time-sensitive biology of vastly unexplored deep-sea biology.

molecular biology↗

bioRxiv2023

A step towards measuring connectivity in the deep-sea: elemental fingerprints of mollusk larval shells discriminate hydrothermal sites

Deep-sea hydrothermal-vent systems are under investigation for base and precious metal exploitations. The impact of mining will depend critically on the ability of larval dispersal to connect and replenish endemic populations. However, assessing connectivity is extremely challenging, especially in the deep sea. Here, we investigate the potential of elemental fingerprinting of mollusc larval shells to discriminate larval origins between multiple hydrothermal sites in the Southwest Pacific Ocean. The gastropod Shinkailepas tollmanni represents a suitable candidate as it uses capsules to hold larvae before dispersal, which facilitates sampling and ensures mineralization occurs on the site of origin. Multielemental microchemistry was performed using cutting-edge femtosecond laser ablation Inductively Coupled Plasma Mass Spectrometry analysis to obtain individual measurements on 600 encapsulated larval shells. We used classification methods to discriminate the origin of individuals from 14 hydrothermal sites spanning over 3,500 km, with an overall success rate of 70%. When considering less sites within more restricted areas, reflecting dispersal distances reported by genetic and modelling approaches, the success rate increased up to 86%. We conclude that individual larval shells register site-specific elemental signatures that can be used to assess their origin. These results open new perspectives to get direct estimates on population connectivity from the geochemistry of pre-dispersal shell of recently settled juveniles.

ecology↗