Pycnodont fishes (Actinopterygii, Pycnodontiformes) from the Upper Cretaceous (lower Turonian) Akrabou Formation of Asfla, Morocco

Abstract

The Upper Cretaceous (upper Cenomanian–middle Turonian) Akrabou Formation of Asfla, southeast Morocco is renowned for exceptionally preserved, often three-dimensional bony and cartilaginous fish fossils. Teleosts, rare holosteans and chondrichthyans are well known from the so-called ‘Goulmima ichthyological assemblage’, however pycnodonts (Actinopterygii, Pycnodontiformes) have received scant attention and remain undescribed until now. Five nominal species are recognised in the assemblage, including two new forms: Neomesturus asflaensis gen. et sp. nov. and Paranursallia cavini sp. nov. The Italian genus Polazzodus is reported in Morocco for the first time. Specimen taphonomy is examined in the context of substrate consistency and oxygenation of an outer shelf carbonate platform setting. Diversity and ecological disparity of the Goulmima assemblage is revised in regard to trophic partitioning with durophagy seemingly more diverse than previously recognised. Comparisons with other pycnodont-bearing horizons of similar age demonstrate strong faunal affinities between the Asfla pycnodonts and those in the western Tethys and South Atlantic.

A new cuspidate ptychodontid shark (Chondrichthyes; Elasmobranchii), from the Upper Cretaceous of Morocco with comments on tooth functionalities and replacement patterns

“…2B ) testifying to middle to outer ramp early Turonian marine environment (e.g. Lézin et al, 2012 ; Meister et al, 2017 ; Villalobos-Segura et al, 2019 ; Cooper and Martill, 2020 ; Veysey et al, 2020 ).…”

“…2 ), searching for macrofossils, such as exceptionally preserved vertebrate remains usually embedded in calcareous nodules (e.g. Bardet et al, 2003a , b ; Cavin et al, 2010 ; Claeson et al, 2013 ; Angst and Bardet, 2015 ; Allemand et al, 2018 ; Cooper and Martill, 2020 ; Villalobos-Segura et al, 2021 ). In particular, a sequence of alternating facies succession consisting of fossiliferous packstones, chalky marls, cherts and vertebrate-bearing nodular horizons belonging to the Asfla Member ( Fig.…”

“…2B ) of the Akrabou Fm of the Asfla area are targeted for vertebrate fossils (e.g. Cavin et al, 2010 ; Claeson et al, 2013 ; Angst and Bardet, 2015 ; Villalobos-Segura et al, 2019 ; Cooper and Martill, 2020 ). The Asfla Member is assigned to the early Turonian based on its ammonite fauna ( Mammites nodosoides Zone; Meister et al, 2017 ; Kennedy et al, 2008 ; Cavin et al, 2010 ).…”

“…mosasauroids and plesiosaurs) and, more rarely, elasmobranchs (e.g. Bardet et al, 2003a , b ; Kennedy et al, 2008 ; Cavin et al, 2010 ; Claeson et al, 2013 ; Angst and Bardet, 2015 ; Gale et al, 2017 ; Meister et al, 2017 ; Allemand et al, 2018 ; Villalobos-Segura et al, 2019 , 2021 ; Cooper and Martill, 2020 ). Additionally, the limestones of the Akrabou Fm include shell beds, with a low-diversified bivalve assemblage, and stromatolites in various horizons ( Kennedy et al, 2008 ; Cooper and Martill, 2020 ).…”

“…Additionally, three-dimensionally preserved skeletal remains of batoids (e.g. platyrhinid and sclerorhynchid) were described from the Turonian of the Goulmima region (Errachidia Province, southeastern Morocco; see Claeson et al, 2013 ; Villalobos-Segura et al, 2019 ; Cooper and Martill, 2020 ). Dental remains and other unspecified material assignable to the extinct elasmobranch genus † Ptychodus were briefly reported from the Upper Cretaceous of northern and western Morocco (see also ‘Moroccan record of † Ptychodus ’, below).…”