bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.03.24.642578

Finding the relatives of a critically endangered island endemic reveals the heterogeneous evolution of land snail mitogenomes (Gastropoda: Helicidae)

Korabek, O.·Vardinoyannis, K.·Orstan, A.·Psonis, N.
View original source ↗Export metadata ↓

Abstract

We analysed the phylogenetic relationships of Aristena rechingeri, an extremely rare, large, flat-shelled snail from the Aegean island of Karpathos. Low-depth Illumina sequencing data obtained from an empty shell were available, but there was no reference genome or sequences of nuclear loci from the related taxa, so we attempted to resolve the phylogeny with mitogenome sequences. We confirmed that Aristena is sister to the globular-shelled genera Helix and Maltzanella and not to the similarly flat-shelled and geographically proximate Isaurica from Anatolia. Concurrently, we clarified the status of two other flat-shelled taxa (Isaurica callirhoe, Levantina menkhorsti). However, even data from complete mitogenomes do not resolve most of the intergeneric relationships in the tree. The mitogenome sequences show variation in nucleotide compositions and substitution rates among species, making phylogenetic inference difficult even with complex mixture models. In general, our examination of the properties of the mitogenomes point to their dynamic and varied evolution, which misleads phylogenetic analyses even at shallow phylogenetic depths. Furthermore, we found that duplications within the mitogenomes are not very rare and that protein-coding genes followed by tRNAs typically end with an incomplete stop codon. The latter presents an issue for automatic annotation tools.

Source connections

Explore related subjects

zoologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Korabek, O., Vardinoyannis, K., Orstan, A., Psonis, N.. 2025-03-27. Finding the relatives of a critically endangered island endemic reveals the heterogeneous evolution of land snail mitogenomes (Gastropoda: Helicidae). https://doi.org/10.1101/2025.03.24.642578

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Glutamatergic system in the pelagic tunicates

Tunicates are a sister lineage to vertebrates, with compact, relatively simple nervous systems featuring a single central ganglion, reflecting a minimal complement of chordate functional architecture. Although glutamatergic neurons are the most abundant population in vertebrates, their ancestry remains unclear. Here, we used glutamate immunohistochemical labeling (Glutamate IR) to identify glutamatergic elements in the neural system of the pelagic tunicate Doliolum sp. (Thaliacea). Glutamate IR was observed in all major nerves of the central ganglion, including motor-like terminals on the circular bundles of swim muscles, which were themselves labeled. However, the neuronal somata in the central ganglion were not labeled, suggesting glutamate accumulation in axonal processes and terminals. In contrast, we did not identify GABA-containing neural elements. This study suggests that glutamatergic systems were elaborated in the common ancestor of tunicates and vertebrates, although the functional role of glutamate and its role in muscular control need further investigation in these pelagic tunicates.

zoology↗
bioRxiv2026

The enlightened entomologist: fast, non-destructive whole-arthropod clearing for three-dimensional imaging

Arthropods are a strikingly diverse phylum of invertebrates with segmented bodies, chitinous exoskeletons, and jointed limbs, many of which are colloquially referred to as insects. Their pigmented and optically dense bodies pose a considerable challenge for microscopy. While early naturalists focused on external features, modern approaches combining tissue clearing and fluorescence microscopy seek to explore internal anatomy in three dimensions. However, both chemical clearing and three-dimensional (3-D) microscopy are specialized techniques and often require considerable adaptation and optimization across species. Here, we introduce a versatile, fast, effective and non-toxic clearing method that renders diverse arthropods transparent within hours to days. Existing upright microscopes or macroscopes can be upgraded with a modular and affordable light-sheet microscope, allowing rapid volumetric imaging of arthropods. Our pipeline is fully compatible with dye staining and immunofluorescence labeling, while endogenous autofluorescence provides valuable anatomical context and facilitates 3-D reconstruction.

zoology↗
bioRxiv2026

Wildlife disease surveillance under uncertainty: an adaptive search-theoretic framework for early detection of transboundary animal diseases

Rapid detection is critical for successful management of transboundary animal disease incursions in wild host populations. However, decisions about how best to allocate wildlife disease surveillance effort must be made under high uncertainty. Risk-based surveillance can improve efficiency but approaches that focus surveillance too narrowly on expected high risk areas could have low power to detect unexpected events. We developed and field-tested an adaptive, search-theoretic surveillance framework for detecting transboundary animal disease incursions in wild ungulates in New South Wales, Australia. Key principles that guided the frameworks development included accommodating uncertainty, regularly updating search priorities based on expected risk and spatial coverage, and a flexible structure that allows the system to respond to changing information or conditions over time. We created a coarse state-wide risk map that served as a weakly informative prior describing expected variability in disease incursion risk, loosely focused on foot and mouth disease virus (FMDv). Risk and search values were updated every three months based on realised surveillance effort and estimated detection probabilities over the preceding 12 months, meaning that areas of persistently high risk could nonetheless have low search value if they had recently been intensively searched. Surveillance activities collected blood and swab samples from 1,964 wild pigs (Sus scrofa) during 110 sampling occasions over a two-year evaluation and refinement period. Activities sought to simulate FMDv surveillance operations, but FMDv serological tests were not available at the time. Effort was consistently concentrated in areas of high search value, with at least 74% of sampled cells in the highest risk class. Estimated surveillance system sensitivity ranged from 0.86 to 0.93 over five successive updating cycles and increased as operational procedures were refined. Although the surveillance program was based on FMDv incursion risk, it also fulfilled its secondary objective of detecting unexpected events, including detecting Japanese encephalitis virus in wild pigs before detections in humans and domestic animals. By combining risk-based surveillance with adaptive updating of search priorities in a modular structure, the framework provided a flexible and generalisable approach for early detection of transboundary and emerging animal disease incursions in wildlife populations under high uncertainty.

zoology↗