Combining palaeontological and neontological data shows a delayed diversification burst of carcharhiniform sharks likely mediated by environmental change

Abstract

Estimating deep-time species-level diversification processes remains challenging. Both the fossil record and molecular phylogenies allow the estimation of speciation and extinction rates, but each type of data may still provide an incomplete picture of diversification dynamics. Here, we combine species-level palaeontological (fossil occurrences) and neontological (molecular phylogenies) data to estimate deep-time diversity dynamics through process-based birth–death models for Carcharhiniformes, the most speciose shark order today. Despite their abundant fossil record dating back to the Middle Jurassic, only a small fraction of extant carcharhiniform species is recorded as fossils, which impedes relying only on the fossil record to study their recent diversification. Combining fossil and phylogenetic data, we recover a complex evolutionary history for carcharhiniforms, exemplified by several variations in diversification rates with an early low diversity period followed by a Cenozoic radiation. We further reveal a burst of diversification in the last 30 million years, which is partially recorded with fossil data only. We also find that reef expansion and temperature change can explain variations in speciation and extinction through time. These results pinpoint the primordial importance of these environmental variables in the evolution of marine clades. Our study also highlights the benefit of combining the fossil record with phylogenetic data to address macroevolutionary questions.

The appendicular skeleton of the enigmatic shark Leptocharias smithii in comparison with other sharks of the order Carcharhiniformes (Elasmobranchii: Leptochariidae)

“…In the hypotheses of Brée et al (2022) and Silva and Vaz (2023), the monophyly of the order Carcharhiniformes would be supported by the presence of three articular regions (facets) for the articulation of the pectoral basals (character 1), and the presence of three condyles for the articulation of the first enlarged pelvic radial and the basipterygium (Silva & Carvalho, 2015;Silva & Datovo, 2021;Silva & Vaz, 2023;; character 2). Another putative synapomorphy that would support the monophyly of this order is the position of the mesopterygium, which overlaps the metapterygium in ventral view (character 3).…”

Earliest Danian outer neritic elasmobranch assemblages reveal an environmentally controlled faunal turnover at the Cretaceous–Palaeogene boundary in the northern Tethyan Realm (Austria)

“…However, deep‐marine settings are important for the evolution and diversification of some elasmobranch groups (Brée et al . 2022), such as Squaliformes (Underwood 2006). As indicated above, none of the five squaliform genera having their last occurrence in the deep‐marine environment of the Gerhartstreit Formation at Waidach ( Eoetmopterus , Proetmopterus , Cretascymnus , Protoxynotus , Fredipristis ) has been reported from horizons 8 and 9.…”

“…The high diversity of these clades in the earliest Danian is congruent with the resilience of these orders across the K–Pg event, at a global scale (Brée et al . 2022; Guinot & Condamine 2023). The fact that the strong genus‐level turnover observed at Waidach affects genera that are mostly known to cross the K–Pg boundary, along with the higher elasmobranch diversity found in the first horizons directly above the K–Pg event suggest a strong palaeoenvironmental control over the local elasmobranch diversity pattern observed at Waidach.…”

A Synoptic Review of the Cartilaginous Fishes (Chondrichthyes: Holocephali, Elasmobranchii) from the Upper Jurassic Konservat-Lagerstätten of Southern Germany: Taxonomy, Diversity, and Faunal Relationships

“…The earliest records of this group are from the Middle Jurassic (Bathonian), from which several genera have been described based on isolated teeth [ 24 , 219 ]. During the Cretaceous, the abundance and diversity of carcharhiniform sharks increased [ 234 ], but the highest diversification rates of carcharhiniforms occurred in the Cenozoic, especially in the last 30 Ma [ 235 ].…”