A new suction feeder and miniature teleosteomorph, Marcopoloichthys mirigioliensis, from the lower Besano Formation (late Anisian) of Monte San Giorgio

Paleontologists have identified Marcopoloichthys mirigioliensis, a miniature suction-feeding fish from the late Anisian period, as the smallest known stem teleost. This discovery, derived from fossil records in Monte San Giorgio's lower Besano Formation (southern Switzerland), distinguishes it from its larger relative, Marcopoloichthys furreri, through differences in caudal endoskeleton and fin structures. Measuring approximately 32 mm in standard length, M. mirigioliensis challenges the understanding of early teleost evolution, suggesting a potential link between size reduction and ecological specialization. The study employed comparative anatomical analysis to highlight its unique morphological traits, contributing new insights into Triassic marine biodiversity at this UNESCO World Heritage Site.

Arratia, G., Bürgin, T., & Furrer, H. (2024). A new suction feeder and miniature teleosteomorph, Marcopoloichthys mirigioliensis, from the lower Besano Formation (late Anisian) of Monte San Giorgio. Swiss Journal of Palaeontology, 143(1). https://doi.org/10.1186/s13358-024-00318-5