Abstract: The Pliensbachian–Toarcian interval was marked by major environmental disturbances and a second-order mass extinction. Here, we reappraise the taxonomic, spatiotemporal selective dynamics of extinctions over whole interval, analysing high-resolution dataset 772 ammonite species from NW Tethyan Arctic domains. On average, 40–65% disappeared during each subchronozone, but higher extinction pulses (reaching 70–90%) prevailed Margaritatus to Dispansum Chronozone. main extinctions,...

Here, we advance novel uses of allometric spaces—multidimensional spaces specifically defined by coefficients—with the goal investigating focal role development in shaping evolution morphological disparity. From their examination, operational measures disparity can be derived, complementing standard signals through an intuitive and process-oriented refinement established analytical protocols used studies. Allometric thereby become a promising context to reveal different patterns evolutionary...

SUMMARY Two major research themes in Evolutionary Developmental Biology and Paleobiology, respectively, have each become central for the analysis interpretation of morphological changes evolution: study ontogeny/phylogeny connections, mainly within widespread controversial framework heterochrony; disparity, signal biodiversity, describing secular morphospace occupation during history any given clade. Although enriching their respective fields, these two remained rather isolated to date,...

Abstract Aim Diversity and disparity metrics of all Recent cuttlefishes are studied at the macroevolutionary scale (1) to establish geographical biodiversity patterns these cephalopods species level (2) explore relationships between two metrics. Location Sampling uses what is known about tropical, subtropical warm temperate Old World based on a literature review measurements museum specimens. Some 111 spread across seventeen biogeographical areas serve as basic units for exploring diversity...

The explosive ammonoid rediversification after the Permian–Triassic mass extinction is now well understood in terms of taxonomic richness and biogeography. Using an updated dataset Early Triassic ammonoids, we compare morphological disparity patterns at regional global scales. Disparity evolved similarly both scales, suggesting a influence abiotic factors. Morphological diversification occurred early Smithian marked contraction morphospace took place during end-Smithian extinction. We...

The shell size of 1236 ammonite species representing all known Early Jurassic faunas is analyzed. Size patterns are studied for the entire period and then at biozone scale first four stages (28 Myr), during which ammonites recovered from crisis Triassic/Jurassic (T/J) boundary. Our analysis reveals that (1) a continuum (normal distribution “dwarfs” to “giants”) exists ammonites; (2) although there no sustained trends (e.g., Cope's rule), succession not monotonous may differ conspicuously one...

Evolutionary radiations are fascinating phenomena corresponding to a dramatic diversification of taxa and burst cladogenesis over short periods time. Most evolutionary have long been regarded as adaptive but this has seldom demonstrated with large-scale comparative datasets including fossil data. Originating in the Early Jurassic, irregular echinoids emblematic spectacular mobile marine faunas during Mesozoic Marine Revolution. They diversified they colonized various habitats, now constitute...

New coleoid cephalopods are described from statolith remains the Middle Eocene (Middle Lutetian) of Paris Basin. Fifteen fossil statoliths identified and assigned to Sepiidae (Sepia boletzkyi sp. nov.,? Sepia pira nov.), Loliginidae (Loligo clarkei Ommastrephidae (genus indet.) families. The sediments containing these fossils indicate permanent aquatic settings in infralittoral domain. These range age 46 Mya 43 Mya. Analysis record (from findings here, together with a review previously...

For decades, theoretical morphological studies of different groups organisms have been successfully pursued in biological, paleontological, and computational contexts, often with distinct modeling approaches research questions. A regular influx new perspectives varied expertise has contributed to the emergence a veritable multidisciplinary outlook for morphology. The broadening this discipline is reflected substantial increase number models, leading bewildering diversity that yet be...

Conservation biologists and palaeontologists are increasingly investigating the phylogenetic distribution of extinctions its evolutionary consequences. However, dearth palaeontological studies on that subject lack methodological consensus hamper our understanding major phenomenon. Here we address this issue by (i) reviewing approaches used to quantify selectivity extinction risks; (ii) with a high-resolution dataset whether survivals were phylogenetically clustered among early Pliensbachian...

Abstract Evolutionary radiations have been extensively studied especially in the fossil record and context of postcrisis recoveries. The concept adaptive radiation that emerges from this very broad topic explicitly involves effect adaptation driven by ecological opportunity is considered to be foremost importance. It essential able detect because it points up factors predispose a clade radiate. Adaptive has received much attention recent decades based mostly on studies dealing with clades,...

Abstract Although belemnites form a major clade of extinct cephalopods, the early stage their diversification remains poorly known in time and space. Here we investigate first episodes (order Belemnitida) using new species‐level database encompassing Hettangian–Aalenian interval (Early Jurassic – earliest Middle Jurassic) covering Western Tethys. Rarefied richness shows four‐fold increase from Planorbis chronozone to Ibex chronozone, strong decrease between Margaritatus Spinatum chronozones,...

The present paper deals with the systematic description of belemnite assemblages from Lower Jurassic, collected at Roche Blain quarry, Fresney-le-Puceux. In spite reduced thickness succession Fresney-le-Puceux, 13 successive ammonite chronozones could be documented in this rather unique outcrop situation mainland Europe. Twelve genera and 26 species belemnites belonging to Passaloteuthididae, Hastitidae, Megateuthididae, Salpingoteuthididae, family incertae sedis are described illustrated...

Abstract: The ammonite genus Alocolytoceras Hyatt, 1900 is an uncommon lytoceratid with distinctive shell ornament. A set of 58 specimens, recently collected at Amellago in the central High Atlas (Morocco), has enabled us to trace a succession three species over eight biozones from Toarcian Aalenian. Two specimens Lusitanian Basin are added for comparison. Following review genus, based on original and data literature, seven considered valid. palaeobiogeographical synthesis 13 regions...

We have devised a simple model for assessing the role of development in shaping evolution morphological disparity. Disparity clade at any given time is expressed terms developmental dynamics that lead to variety adult morphotypes observed. use assumed phenotypic manifestations processes, as they could be detected from allometric characterizations, distinguish few, nonexclusive types evolutionary changes ontogeny. On basis this formalization, we describe diversification hypothetical clades,...

Jurassic belemnites represent promising proxies especially for palaeoecological and also palaeobiogeographical reconstructions. However, basic knowledge on taxonomic composition, biostratigraphy diversity of Early is still dramatically low, France. The present study provides new data from the southern part Northwest European Province. More than 700 specimens have been collected along Tournadous section in Causses Basin (Southern France); they ten genera 30 species belonging to Hastitidae,...

Abstract Morphological changes observed in ammonites at the Lias-Dogger (Toarcian-Aalenian) boundary are analyzed here. The study covers all known worldwide over some 2 m.y. (the last two biozones of Toarcian: Pseudoradiosa and Aalensis first biozone Aalenian: Opalinum). Ammonite taxonomy this is still open to question, main disagreements being groupings family or super-family level. evolutionary schema developed by Tintant Mouterde [1981] shows sets Ammonitina for time: (1) dominant...