2016 MARINE LATE JURASSIC ANTARTIC SUMMER FIELDTRIP AT LONGING GAP (AMEGHINO FORMATION): PRELIMINAR REPORT OF THE FINDINGS

GOUIRIC CAVALLI, S.; O'GORMAN, JOSÉ; MOLY JUAN JOSÉ; ACOSTA BURLLAILE, LEONEL; REGUERO, MARCELO

Jornada; XXX Jornadas Argentinas de Paleontología de Vertebrados; 2016

A fieldwork to Longing Gap, Antarctic Peninsula [ca. 112 km to the SW of Marambio (=Seymour) Island]?which has as a main goal to recover fish material? was carried out during January to February of 2016 with the logistic support of the Argentinian Antarctic Institute (IAA) and the collaboration of the Fuerza Aérea Argentina. We explored the Kimmeridgian to Upper Tithonian levels of the Ameghino (=Nordenskjöld) Formation. The findings comprise at least 500 fish specimens, most of them recovered in lower Tithonian levels and a few collected in late Tithonian levels of the Ameghino Formation. Additionally, some scattered and fragmentary material were also found in the Kimmeridgian levels of the Ameghino Formation. Despite several specimens are incomplete, the preservation quality of the early Tithonian fish material is outstanding being most of the specimens articulated or partially articulated. The taxonomic and morphological diversity observed is remarkable; aspidorhynchids are the most common taxa present followed by teleosts; other actinopterygian groups are less abundant. Some fish groups were previously unknown for the Jurassic of Antarctica, to known: semionotiforms and pachycormiforms, moreover their record extends the distribution of both groups to the southernmost part of South America. Despite the fish diversity other marine vertebrates ?ichthyosaurs and pliosauroids?, invertebrates, and plants were recorded by the team in the Kimmeridgian and early Tithonian levels of the Ameghino Formation.