biostudies-literatureGuarneri IUniversità di GenovaCNRSAgence Nationale de la RechercheANRCentre National de la Recherche Scientifique331-343https://www.ebi.ac.uk/biostudies/studies/S-EPMC11897935biostudies-literatureUnknown20(2)The European amphioxus (Branchiostoma lanceolatum) is a member of the chordate subphylum Cephalochordata, and, as such, a key model organism for providing insights into the origin and evolution of vertebrates. Despite its significance and global distribution, detailed characterizations of natural populations of cephalochordates are still very limited. This study investigates the abundance, habitat, and spawning behavior of amphioxus in the North Adriatic Sea. Across 32 sampled sites, adult amphioxus were consistently present, reaching densities exceeding 300 individuals m^- ². DNA barcoding confirmed the species as B. lanceolatum, and environmental analyses revealed an amphioxus preference for slightly gravelly sand with low silt content and a correlation between amphiIntegrative zoologyAmphioxus (Branchiostoma lanceolatum) in the North Adriatic Sea: ecological observations and spawning behavior.PMC11897935FRA2023ANR‐21‐CE34‐0006‐02ANR-21-CE34-0006-02Guarneri IPerez Criado NManfe GAmaroli APestarino MPovero PFerrando STagliapietra DCandiani SSchubert MBellitto DBozzo MCastellano LScapin LSerafini EFiorin RfalseAmphioxus (Branchiostoma lanceolatum) in the North Adriatic Sea: ecological observations and spawning behavior.The European amphioxus (Branchiostoma lanceolatum) is a member of the chordate subphylum Cephalochordata, and, as such, a key model organism for providing insights into the origin and evolution of vertebrates. Despite its significance and global distribution, detailed characterizations of natural populations of cephalochordates are still very limited. This study investigates the abundance, habitat, and spawning behavior of amphioxus in the North Adriatic Sea. Across 32 sampled sites, adult amphioxus were consistently present, reaching densities exceeding 300 individuals m^- ². DNA barcoding confirmed the species as B. lanceolatum, and environmental analyses revealed an amphioxus preference for slightly gravelly sand with low silt content and a correlation between amphi2025-01-01T00:00:00Z2025 Mar2026-04-08T19:48:32.994Z2025-04-04T09:08:03.077ZS-EPMC118979353888615710.1111/1749-4877.12846