Gastrochaenolites Leymerie in the Cenozoic of the Antillean Region

Abstract

As part of a review of its distribution within the Antillean region, well-preserved casts of the boring Gastrochaenolites Leymerie are described from the Neogene Seroe Domi Formation of Aruba, Bonaire and, particularly, Curaçao (ABC Islands), Netherlands Antilles; G. ampullatus Kelly and Bromley, G. torpedo Kelly and Bromley, and G. turbinatus Kelly and Bromley. These trace fossils were originally classified as bivalves, namely Spengleria rostrata? (Spengler), Lithophaga spp. and Rocellaria sp., specimens of which are preserved in at least some of the casts. This is the first record of G. ampullatus from the Antillean region; casts of both siphonal canals are retained by some specimens, making their preservation superior to that of the holotype. Gastrochaenolites turbinatus is also rare in the Antillean region; the specimens from the ABC Islands preserve distinctive concentric grooves on their necks, produced by the borer and indicating the former position of the neck-to-chamber transition. Each Gastrochaenolites ichnospecies is bored by a different bivalve. This study, based on one of the most diverse collections of Gastrochaenolites known from the Antillean region, extend its known diversity and geographic distribution; only the Upper Oligocene of Jamaica shows a greater diversity.