First pachycormiform (Actinopterygii, Pachycormiformes) remains from the Late Jurassic of the Antarctic Peninsula and remarks on bone alteration by recent bioeroders

We describe osteichthyan remains from the Upper Jurassic of the Ameghino (= Nordenskjöld) Formation of the Antarctic Peninsula. The fossils are referred to a suspension-feeding pachycormid based on the shape, morphology, and presence of acus fanunculi (needle teeth) on their gill rakers. Due to the fragmentary condition of the Antarctic material, we refer it to aff. Asthenocormus. The remains described here represent the first record of a suspension-feeding pachycormid from the Upper Jurassic of the Antarctic Peninsula and the oldest pachycormid yet recovered from Antarctica. The new fossil fish supports a possible early dispersal route through the Mozambique Corridor (= Trans-Gondwana or South African Seaway). We also describe the weathering produced by modern lichens, which might be misinterpreted as original bone structure.