A New Early Semionotidae (Semionotiformes, Actinopterygii) from the Upper Ladinian of Monte San Giorgio Area Southern Switzerland and Northern Italy)

A new genus of early Semionotidae, Sangiorgioichthys aldae, was discovered from the Upper Ladinian Kalkschieferzone of Monte San Giorgio, a UNESCO World Heritage Site spanning southern Switzerland and northern Italy. This fossil provides critical insights into the poorly understood early history of Semionotiformes, with distinct morphological features such as ganoine-covered dermal skull bones, an unusually large ventral infraorbital, and specialized dentition. The study employed detailed anatomical analysis to classify the specimen within the Semionotidae family, noting shared diagnostic traits while highlighting unique characteristics that differentiate it from other known taxa. This discovery contributes significantly to understanding the evolutionary trajectory of this ancient fish group during the Triassic period.

TINTORI, A. N. D. R. E. A., & LOMBARDO, C. R. I. S. T. I. N. A. (2007). A NEW EARLY SEMIONOTIDAE (SEMIONOTIFORMES, ACTINOPTERYGII) FROM THE UPPER LADINIAN OF MONTE SAN GIORGIO AREA SOUTHERN SWITZERLAND AND NORTHERN ITALY). Rivista Italiana Di Paleontologia e Stratigrafia, Vol 113, No 3. https://doi.org/10.13130/2039-4942/5881