A Review of <i>Galaxias</i> (Galaxiidae) Fossils from the Southern Hemisphere

• Main Authors: Uwe Kaulfuss, Daphne E. Lee, Jeffrey H. Robinson, Graham P. Wallis, Werner W. Schwarzhans
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Diversity
• Subjects: Miocene; articulated skeletons; otoliths; coprolites; taphonomy; paleoecology
• Online Access: https://www.mdpi.com/1424-2818/12/5/208

The Galaxiidae is a Southern Hemisphere family of freshwater fish, considered to be of Gondwanan origin based on the current distribution of species in New Zealand, Australia (including Tasmania), New Caledonia, Africa, South America, and on some associated and subantarctic islands. The fossil record of galaxiids is extremely sparse and geographically restricted. The only galaxiid fossils currently known come from several Miocene lakes in southern New Zealand. They include more than 100 articulated fishes, some remarkably preserving soft parts such as eyes and skin, skulls and jaw components, and more than 200 isolated otoliths. Common coprolites and <i>in situ</i> preserved gut content at one site (Foulden Maar) indicate the different diets of larvae and adult fish. These discoveries reveal a diverse <i>Galaxias</i> fauna, the presence of lake-locked populations, ontogenetic diet shifts, and representatives of several non-migratory <i>Galaxias</i> lineages associated with inland streams and lakes. There are at least six <i>Galaxias</i> species based on macrofossils and six separate otolith-based species from varied volcanic and regional lacustrine environments. This diversity points to southern New Zealand as a centre of biodiversity and speciation in Galaxiidae in the early to late Miocene.