title: Piscivory in a Miocene Cetotheriidae of Peru: first record of fossilized stomach content for an extinct baleen-bearing whale.
abstract: Instead of teeth, modern mysticetes bear hair-fringed keratinous baleen plates that permit various bulk-filtering predation techniques (from subsurface skimming to lateral benthic suction and engulfment) devoted to various target prey (from small invertebrates to schooling fish). Current knowledge about the feeding ecology of extant cetaceans is revealed by stomach content analyses and observations of behavior. Unfortunately, no fossil stomach contents of ancient mysticetes have been described so far; the investigation of the diet of fossil baleen whales, including the Neogene family Cetotheriidae, remains thus largely speculative. We report on an aggregate of fossil fish remains found within a mysticete skeleton belonging to an undescribed late Miocene (Tortonian) cetotheriid from the Pisco Formation (Peru). Micro-computed tomography allowed us to interpret it as the fossilized content of the forestomach of the host whale and to identify the prey as belonging to the extant clupeiform genus Sardinops. Our discovery represents the first direct evidence of piscivory in an ancient edentulous mysticete. Since among modern mysticetes only Balaenopteridae are known to ordinarily consume fish, this fossil record may indicate that part of the cetotheriids experimented some degree of balaenopterid-like engulfment feeding. Moreover, this report corresponds to one of the geologically oldest records of Sardinops worldwide, occurring near the Tortonian peak of oceanic primary productivity and cooling phase. Therefore, our discovery evokes a link between the rise of Cetotheriidae; the setup of modern coastal upwelling systems; and the radiation of epipelagic, small-sized, schooling clupeiform fish in such highly productive environments.
authors.affiliation: Dipartimento di Scienze della Terra, Università di Pisa, via Santa Maria 53, 56126, Pisa, Italy. alberto.collareta@for.unipi.it.|Dottorato Regionale in Scienze della Terra Pegaso, via S. Maria 53, 56126, Pisa, Italy. alberto.collareta@for.unipi.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Collareta
authors.affiliation: Dipartimento di Scienze della Terra, Università di Pisa, via Santa Maria 53, 56126, Pisa, Italy.
authors.forename: Walter
authors.initials: W
authors.lastname: Landini
authors.affiliation: Institut Royal des Sciences Naturelles de Belgique, D.O. Terre et Histoire de la Vie, rue Vautier 29, 1000, Brussels, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Lambert
authors.affiliation: Natuurhistorisch Museum Rotterdam, Westzeedijk 345, 3015 AA, Rotterdam, The Netherlands.
authors.forename: Klaas
authors.initials: K
authors.lastname: Post
authors.affiliation: Dipartimento di Scienze della Terra, Università di Pisa, via Santa Maria 53, 56126, Pisa, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Tinelli
authors.affiliation: Scuola di Scienze e Tecnologie, Università di Camerino, via Gentile III da Varano 1, 62032, Camerino, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Di Celma
authors.affiliation: Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, via G. Moruzzi 1, 56124, Pisa, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Panetta
authors.affiliation: Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, via G. Moruzzi 1, 56124, Pisa, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Tripodi
authors.affiliation: Istituto di Fisiologia Clinica, Consiglio Nazionale delle Ricerche, via G. Moruzzi 1, 56124, Pisa, Italy.
authors.forename: Piero A
authors.initials: PA
authors.lastname: Salvadori
authors.affiliation: Radiologia Diagnostica e Interventistica, Università di Pisa, via Roma 67, 56126, Pisa, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Caramella
authors.affiliation: Dipartimento di Biologia, Università di Pisa, via L. Ghini 13, 56126, Pisa, Italy.|Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, 2050, Wits, South Africa.
authors.forename: Damiano
authors.initials: D
authors.lastname: Marchi
authors.affiliation: Departamento de Paleontologia de Vertebrados, Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos, Avenida Arenales 1256, Lima, 14, Peru.
authors.forename: Mario
authors.initials: M
authors.lastname: Urbina
authors.affiliation: Dipartimento di Scienze della Terra, Università di Pisa, via Santa Maria 53, 56126, Pisa, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bianucci
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000000981:diagnostic imaging; D005399:Fishes / Q000033:anatomy & histology* / Q000145:classification; D005580:Fossils; D005766:Gastrointestinal Contents; D010568:Peru; D011235:Predatory Behavior; D014907:Whales; D055114:X-Ray Microtomography
keywords: Cetotheriidae; Fossil stomach content; Micro-CT; Miocene; Mysticeti; Sardinops