The oldest platylepadid turtle barnacle (Cirripedia, Coronuloidea): a new species of Platylepas from the Lower Pleistocene of Italy

Alberto Collareta,Antonietta Rosso,Mark Bosselaers,Rossana Sanfelippo,Gianni Insacco,Agatino Reitano,Giovanni Bianucci

doi:10.5852/ejt.2019.516

Abstract

Coronuloid barnacles are epibionts of several marine vertebrates (including cetaceans and sea turtles) as well as invertebrates, and are assigned to two families of turtle barnacles (Chelonibiidae Pilsbry, 1916 and Platylepadidae Newman & Ross, 1976) and one family of whale barnacles (Coronulidae Leach, 1817). Chelonibiids and coronulids have a scanty, albeit significant fossil record extending back to the Eocene and Pliocene, respectively; in turn, the fossil record of platylepadids is limited to a single record from the Upper Pleistocene. Here we report on an isolated carinolateral compartment of Platylepas Gray, 1825, the type genus of the family, from Lower Pleistocene (Gelasian) epibathyal deposits exposed at Milazzo (Sicily, Italy). This specimen is here designated holotype of a new species, †Platylepas mediterranea sp. nov. We argue that, like most extant members of Platylepas, †P. mediterranea sp. nov. lived partially embedded in the skin of a sea turtle. This record of an extinct platylepadid – the first from the Mediterranean region and the second worldwide – pushes back the fossil record of Platylepadidae to the lowermost Quaternary, thus possibly supporting an even earlier (e.g., Neogene) timing for the origin of this family and adding a new chapter to the evolutionary history of one of the most diverse and successful lineages of epizoic crustaceans.

Highlights

IntroductionExtant turtle and whale barnacles (Cirripedia Burmeister, 1834, Thoracica Darwin, 1854, Coronuloidea Leach, 1817) are epibiotic organisms that attach themselves to the external surface of several saltwater and estuarine vertebrates (including toothed and baleen whales, sea turtles, sea cows, crocodiles, snakes and bony fish) and invertebrates (including crabs, horseshoe crabs and crayfish) (Hayashi 2013, and references therein)
Extant turtle and whale barnacles (Cirripedia Burmeister, 1834, Thoracica Darwin, 1854, Coronuloidea Leach, 1817) are epibiotic organisms that attach themselves to the external surface of several saltwater and estuarine vertebrates and invertebrates (Hayashi 2013, and references therein)
Like most extant members of Platylepas, †P. mediterranea sp. nov. lived partially embedded in the skin of a sea turtle

Summary

Introduction

Extant turtle and whale barnacles (Cirripedia Burmeister, 1834, Thoracica Darwin, 1854, Coronuloidea Leach, 1817) are epibiotic organisms that attach themselves to the external surface of several saltwater and estuarine vertebrates (including toothed and baleen whales, sea turtles, sea cows, crocodiles, snakes and bony fish) and invertebrates (including crabs, horseshoe crabs and crayfish) (Hayashi 2013, and references therein). Coronuloid barnacles are assigned to three families, namely Coronulidae, Chelonibiidae and Platylepadidae (Ross & Frick 2011). The fossil history of Chelonibiidae dates back to the Paleogene (with the earliest representative of the family, †Emersonius cybosyrinx Ross in Ross & Newman, 1967, from the upper Eocene Williston Limestone of Florida, USA), whereas coronulids seemingly appeared later, starting with †Coronula bifida Bronn, 1831 in a few Upper Pliocene deposits worldwide (e.g., Marquet et al 2009). The fossil record of Platylepadidae, a widely distributed and well-diversified family of small-sized, warm-water coronuloids, with at least fourteen extant species in six genera (Ross & Frick 2011), is much less extensive and, comprises merely the holotype of †Platylepas wilsoni Ross, 1963 from the Upper Pleistocene Pamlico Formation of Florida, USA

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