Biology subjects

Kocakova, K.

Publications and source records attributed to Kocakova, K..

3 recordsLinked to original sources

bioRxiv2026

Robust evidence for modest diversity loss across the K/Pg in neoselachians: Response to Guinot et al.

We reconstructed the neoselachian diversity over the past 145 million years using new occurrence dataset and DeepDive1-3. We recovered a small decline through the K/Pg following a steady increase during the Cretaceous, and a prolonged, substantial decline towards the present following a mid-Eocene peak2. Guinot et al. argue that our conclusions are compromised by problems in the underlying data and by the way extinction magnitude across the K/Pg was quantified. They cast doubt particularly on the pattern across the K/Pg, which they consider to be at odds with all previous analyses. They raise no issue with the Cretaceous trend, even though it was recovered with the same dataset and methods. We audited the alleged data issues reported in Guinot et al. and found that they mostly reflect operational choices (see Supplementary Information). However, we applied their data treatment and ran sensitivity tests to evaluate how this approach affects our results, specifically around the K/Pg. None of our tests recovered a diversity collapse for neoselachians during this interval. As such, we demonstrate that our findings are robust and consistent across different data treatments.

paleontology↗

bioRxiv2025

Global gaps and priorities for shark and ray conservation: Integrating threat, function, and evolutionary distinctiveness

Elasmobranchs (sharks, rays, and skates) face unprecedented extinction risk, with over one-third of species threatened primarily by overfishing. While marine protected areas (MPAs) are essential tools to help safeguard marine ecosystems and the species that inhabit them, we lack a comprehensive understanding of how well elasmobranchs are protected globally. Here, we (1) evaluate the current level of protection for elasmobranchs, (2) employ CAPTAIN reinforcement learning algorithm to identify areas that optimise conservation based on species level of threat and their functional and evolutionary distinctiveness, and (3) examine conservation conflicts and opportunities by identifying areas where conservation priorities overlap with high and low fishing pressures. Our analysis revealed severe protection deficits, with elasmobranchs having on average only 3% of their range covered by no-take MPAs and 64% of species under-represented relative to random expectations. Areas that optimise conservation priorities consistently converged in Australian, Southeast Asia, the Indian Ocean, Atlantic Africa, European Atlantic coasts, the Caribbean, and South American Atlantic regions. However, areas of highest conservation priority often coincided with intensive fishing, particularly in East Asian seas, highlighting conservation conflicts requiring strategic management. Our results provide actionable insights for policymakers to optimise conservation strategies and maximise biodiversity retention. TeaserReinforcement learning identifies priority areas to expand ocean protection for unique and irreplaceable elasmobranchs.

ecology↗

bioRxiv2025

FINS - A global occurrence dataset of fossil neoselachians from the Cretaceous to the Quaternary

MotivationModern sharks, rays and skates (Neoselachii) are a diverse, globally distributed, and ecologically important group. They possess a rich, geologically extensive, and well-documented fossil record that provides a powerful basis for studying their macroevolution, paleoecology and biogeography. However, addressing paleobiological questions require quantifying the fossil record trough occurrences, i.e., records of the presence of a taxon at a unique location in space and time. Although the Paleobiology Database (PBDB) offers an invaluable source of fossil occurrences, it still does not provide a complete compilation of neoselachian data. To facilitate exploring questions in quantitative paleobiology, here we present the Fossil Neoselachian (FINS) dataset--a comprehensive, systematically curated global synthesis of fossil occurrences spanning the past 145 million years. Main types of variables containedFINS consists of fossil occurrences, each linked to a collection (location where fossils were reported from) and a source (citation of the publications from which data was obtained). Occurrence data mostly consists of taxonomic variables (e.g., classification, names and ranks), status (extinct/extant) and abundance. Collection data provide geographic (e.g., country, ocean and paleo-coordinates) and geological (e.g., formation and age) variables. All data was subjected to a meticulous curation process, which is described through taxonomic and age validation variables. Spatial location and grainGlobal, with fossil occurrences recovered from all continents. Time period and grainFrom the Cretaceous to the Quaternary (145 - 0 Ma), with temporal resolution generally corresponding to geological stages or epochs. Major taxa and level of measurementNeoselachians (superorders: Selachimorpha and Batoidea). FINS comprises 30,100 occurrences from 5,972 collections and 1,990 publications. It consists of 1,606 species, 512 genera, 88 families and 14 orders. Over 70% of occurrences are identified at the species level. Overall, FINS effectively doubles the number of neoselachian records previously available in the PBDB and substantially expands their geographic coverage, particularly in the Global South. Software formatThe dataset is provided an .xlsx spreadsheet with four tabs - Collections, Occurrences, References_Literature and References_PBDB.

paleontology↗