Abstract
A new double‐armoured herring of the clupeomorph order Ellimmichthyiformes, Eoellimmichthys superstes gen. et sp. nov., is described herein based on a single partially complete specimen from the early Eocene Pesciara site of the Bolca Konservat‐Lagerstätte, north‐eastern Italy. The fossil documented herein exhibits a unique combination of features (e.g. ornamentation of the skull bones; medial fusion of the contralateral halves of the neural arches of abdominal vertebrae; teeth on endopterygoid, parhypural fused to the first preural centrum; presence of a short series of 6 (or 7) predorsal scutes increasing in size posteriorly; postpelvic scutes bearing very prominent spines), which clearly supports its recognition as a new genus and species of the family Paraclupeidae. Evidence is provided to show that Eoellimmichthys gen. nov. is most closely related phylogenetically to the Early Cretaceous genus Ellimmichthys. The new taxon described herein represents the youngest marine occurrence of the family Paraclupeidae and, more generally, of the order Ellimmichthyiformes, suggesting that the shallow marine settings of the Tethys might have favoured the persistence of certain fish lineages that were severely affected by the end‐Cretaceous mass extinction.
Highlights
DOUBLE - ARMOURED herrings of the order Ellimmichthyiformes constitute an extinct clade of clupeomorph fishes characterized by a remarkably wide palaeogeographical and palaeoenvironmental distribution in marine, estuarine and freshwater deposits of Africa, Asia, Europe, and North and South America
This clupeomorph clade currently includes about 40 species arranged in 19 genera spanning from the Early Cretaceous to the middle Eocene (e.g. Grande 1982; Alvarado-Ortega & Melgarejo-Damian 2017; Figueiredo & Ribeiro 2017)
After the end-Cretaceous mass extinction and until their final extinction in the middle Eocene, the representatives of the Ellimmichthyiformes experienced a drastic drop in their diversity and disparity, with the last Palaeogene taxa being restricted to the freshwaters of North and South America, and China (Grande 1982; Chang & Maisey 2003; Marrama & Carnevale 2017a), providing further support for the hypothesis that continental waters suffered lower proportionate extinctions compared to marine environments (Robertson et al 2013)
Summary
DOUBLE - ARMOURED herrings of the order Ellimmichthyiformes constitute an extinct clade of clupeomorph fishes characterized by a remarkably wide palaeogeographical and palaeoenvironmental distribution in marine, estuarine and freshwater deposits of Africa, Asia, Europe, and North and South America (see e.g. Grande 1982, 1985; Chang & Maisey 2003; Forey et al 2003; Murray & Wilson 2013; Bannikov 2015; Vernygora & Murray 2015; Marrama & Carnevale 2017a). Grande 1982, 1985; Chang & Maisey 2003; Forey et al 2003; Murray & Wilson 2013; Bannikov 2015; Vernygora & Murray 2015; Marrama & Carnevale 2017a) This clupeomorph clade currently includes about 40 species arranged in 19 genera spanning from the Early Cretaceous to the middle Eocene The calcareous sequence of the Pesciara site has been traditionally referred to as ‘Calcari Nummulitici’, an informal unit of Eocene age widely distributed in north-eastern Italy (Papazzoni & Trevisani 2006) This succession consists of a cyclic alternation of about 20 m of finely laminated micritic limestones (containing exquisitely well-preserved fishes, plants and invertebrates) and coarse-grained biocalcarenite/biocalcirudite with a rich benthic fauna. The results of a recent quantitative palaeoecological analysis by Marrama et al (2016c) suggested that the Pesciara fish assemblage was characterized by a sharp oligarchic structure dominated by planktivorous fishes (mostly clupeoids), whereas the sedimentological and taphonomic features concur to suggest that the fossiliferous sediments accumulated in a shallow intraplatform basin in which anoxic conditions and the development of a biofilm at the bottom promoted the high-quality preservation of the fossils (see Papazzoni & Trevisani 2006)
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