Biology subjects

Pante, E.

Publications and source records attributed to Pante, E..

4 recordsLinked to original sources

bioRxiv2025

Unexpected diversity of Isidoides (Anthozoa: Octocorallia: Isidoidae) revealed by morphology and phylogenomics analysis with descriptions of four new species

Isidoidae Heestand Saucier, France & Watling, 2021 is a rare octocoral family currently represented by a single genus and species, Isidoides armata Nutting, 1910 recorded in the western Pacific Ocean. The taxonomic status and diversity of Isidoides is unclear, due to the lack of diagnostic taxonomic features and limited taxon sampling. Based on 23 Isidoides specimens obtained from the northwestern to southwestern Pacific, we carried out morphological and phylogenetic analyses to reveal the taxonomic status of new species and develop reliable features for species identification. The 23 specimens could be classified into four well-supported clades by the phylogenomic analysis of ultraconserved elements (UCEs), four groups by 28S rDNA, and two groups by mtMutS-cox1. Integrating morphology and molecular data, we uncovered unexpected diversity of Isidoides composed of the known species Isidoides armata and three new species, viz., I. elegans sp. nov., I. gracilis sp. nov. and I. pseudarmata sp. nov. The morphological analysis showed high intraspecific morphological variation in colony color and the size, shape and arrangement of polyps. By contrast, sclerite forms with their surface sculpturing are more diagnostic features for species identification. Our phylogenetic and species delimitation analyses indicate that UCEs have higher resolution than the nuclear 28S rDNA and the mitochondrial genes mtMutS and cox1 for species discrimination within Isidoidae. ZooBank: urn:lsid:zoobank.org:pub:392485F5-502E-4383-B153-45B167571190

zoology↗

bioRxiv2025

Image-based ecological assessment of deep-sea sponge, coral and other cnidarian assemblages through a morpho-functional approach

AO_SCPLOWBSTRACTC_SCPLOWPorifera and Cnidaria are key phyla of marine ecosystem functioning. Slow-growing and long-lived, they show limited resilience to human disturbances and are therefore commonly used as indicator taxa of Vulnerable Marine Ecosystems. Their diversity and distribution largely rely on seafloor images, but image-based identification (ID) of sponges and cnidarians beyond class/order ranks is hindered by morphological plasticity and convergence, and the need of microscopic diagnostic characters or molecular markers that are not accessible on images. Higher-rank taxonomy also poorly reflects their morphological and functional diversity. To address this issue, we applied an image-based classification relying on multiple macro-morphological traits to define statistically morpho-functional groups (MFGs) based on these traits, then used as response variables in ecological analyses, instead of taxa. We applied this framework to seamounts and island slopes in the Mozambique Channel, a poorly sampled region where taxonomic limitations are acute. We aimed to evaluate the relevance of a sponge/cnidarian morpho-functional approach to characterise their diversity and distribution at multiscales, responses to environmental gradients and structuring roles on the megabenthic community. We identified 37 sponge and 34 cnidarian MFGs with varying distributions among sites. MFGs richness and beta diversity varied among seamounts, and between seamounts and island slopes. Hydrology explained 26% of the sponge MFG spatial structure at the channel scale, while topography and substrate played a main role at a smaller scale in the northern part of the channel (17-23%). Some sponge/cnidarian MFGs co-structured with other megabenthic taxa (e.g., sea urchins, comatulids, ophiuroids). This morpho-functional approach, especially effective for sponges, allowed quantifying morphological variation of habitat-forming taxa using qualitative traits, identifying environmental drivers shaping the spatial distribution of these traits, and characterising potential biogenic habitats they provide for other megabenthic organisms. The framework proposes metrics to detect and quantify the heterogeneity and spatial variability of potentially vulnerable biogenic habitats in imagery-based studies.

ecology↗

bioRxiv2025

Two de novo transcriptome assemblies and functional annotations from juvenile cuttlefish (Sepia officinalis) under various metal and pCO2 exposure conditions

AO_SCPLOWBSTRACTC_SCPLOWThe cuttlefish Sepia officinalis is a precious model in behavioural and neurobiology studies. It is currently facing combined environmental changes related to the anthropogenic global change. However, genomic resources available to support investigations tackling this issue are still scarce. Therefore, we present two annotated de novo transcriptome assemblies from recently hatched (whole body) and one-month-old (head) Sepia officinalis juveniles. Both assemblies rely on an important read depth validated by a pseudo-rarefaction analysis, and gathered several individuals from various metal and pCO2 exposure conditions. After redundancy reduction, assemblies from newly hatched and one-month-old individuals comprised 230,672 and 370,613 transcripts with 35,590 and 44,233 putative ORFs, respectively, and an annotation rate arounf 70%. Assemblies were compared to each other, revealing age-specific transcriptomic landscapes. These two assemblies constitute highly valuable genomic resources complementing reference genome assembly and facilitating the investigation of transcriptomic endpoints in environmental studies considering coleoid cephalopods.

genomics↗

bioRxiv2022

Discordant population structure inferred from male- and female-type mtDNAs from Limecola balthica, a bivalve species characterized by doubly uniparental inheritance of mitochondria

Doubly Uniparental Inheritance (DUI) of mitochondria is a remarkable exception to the Strictly Maternal Inheritance (SMI) in metazoans. In species characterized by DUI --almost exclusively gonochoric bivalve mollusks--females (F) transmit mitochondria to offspring of both sexes, while males (M) pass on their mitochondria exclusively to their sons. Under DUI, males are heteroplasmic, somatic tissues containing F-transmitted mtDNA and gametic cells containing M-transmitted mtDNAs. The aforementioned transmission routes make M- and F-transmitted mtDNA interesting as sex-specific markers which can differ in their effective population sizes, mutation rates, and selective constraints. For these reasons, looking at both markers can provide significant insights into the genetic structure of populations and investigate its determinants. In this study, we document differences in genetic diversity, divergence, inter-populational differentiation and biogeographic structure between M- and F-type cox1 mt genes in the Baltic tellin (Macoma balthica) to test whether cox1m and cox1f genes bear the marks of similar phylogeographic histories. These markers were sequenced for 302 male individuals sampled from the North Sea to the Gironde Estuary (Southern France) encompassing the intra-subspecific M. b. rubra hybrid zone in the Gulf of Saint Malo. Both genes supported a scenario of cladogenesis of M.b. rubra clades prior to the last glacial maximum. Nucleotide diversity and net divergence were over twice higher in cox1m compared to cox1f. Genetic differentiation between northern and southern populations was nearly 3 times higher at cox1m compared to cox1f (global {Phi}ST = 0.345 and 0.126 respectively) and the geographic localization of the strongest genetic break significantly differed between the markers (Finistere Peninsula at cox1f; Cotentin Peninsula at cox1m, [~]250 km apart). A higher mutation rate, relaxed negative selection and differences in effective population sizes (depending on locations) at cox1m could explain differences in population genetic structure. As both F- and M-type mtDNAs interact with nuclear genes for oxidative phosphorylation and ATP production, geographical discordances in genetic clines in a context of secondary contact could be linked to mito-nuclear genetic incompatibilities.

evolutionary biology↗