Jérémie Bardin

• PhD
• Engineer at Sorbonne University

Understanding the origin and evolution of the mineralized skeleton is crucial for unravelling vertebrate history. However, several limitations hamper our progress. The first obstacle is the lack of uniformity and clarity in the literature for the definition of the tissues of concern, especially of enameloid(s) and enamel(s), resulting in ambiguous...

The asymmetry observed in rhynchonellid brachiopod shells has been discussed for decades and continues to attract attention. This noteworthy modification of the anterior margin morphology during the ontogeny has evolved several times in rhynchonellids, and seems to reflect a genetic basis. First, we try to clarify the terminology regarding asymmetr...

Until the advent of phylogenomics, the atypical morphology of extant representatives of the insect orders Grylloblattodea (ice‐crawlers) and Mantophasmatodea (gladiators) had confounding effects on efforts to resolve their placement within Polyneoptera. This recent research has unequivocally shown that these species‐poor groups are closely related...

Les relations phylogénétiques des espèces récentes du genre Homo (i.e. celles ayant vécu il y a moins de 1 Ma) sont âprement débattues, comme en attestent les discussions autour d’Homo floresiensis, H. heidelbergensis ou encore H. longi. Cependant, il semble que les méthodes phylogénétiques, abondamment utilisées en paléontologie sont trop peu appl...

Allometry, i.e., morphological variation correlated with size, is a major pattern in organismal evolution. Since size varies both within and among species, allometry occurs at different variational levels. However, the variability of allometric patterns across levels is poorly known since its evaluation requires extensive comparative studies. Here,...

Fossils of extinct jawless vertebrates are pivotal to deciphering the evolutionary paths that led to the various forms of the vertebrate skeleton. For example, Pteraspidomorphs (stem‐gnathostomes), such as the Ordovician Astraspis , display some of the oldest remains of bony and ‘dental’ (dentine and enameloid) tissues. However, the identification...

Menispermaceae are an angiosperm family of mostly climbing plants distributed throughout tropical regions. The fruits in this family have a strong sclerified endocarp and can be used for reliable species‐level identifications, even in a fossilized form. New Paleocene‐age menispermaceous endocarps have recently been discovered in South America and A...

Increased severity or recurrence risk of some specific infectious diarrhea, such a salmonellosis or Clostridium difficile colitis, have been reported after an appendectomy in human patients. While several other mammals also possess an appendix, the suspected protective function against diarrhea conferred by this structure is known only in humans. F...

Reptiles represent one of the most diverse groups of tetrapod vertebrates. Extant representatives of reptiles include lepidosaurs (lizards), testudines (turtles) and archosaurs (crocodiles and birds). In particular, they show an important locomotor diversity with bipedal, quadrupedal and facultatively bipedal taxa. This diversity is accompanied by...

Skeletal remains of extinct jawless vertebrates are pivotal to deciphering the evolutionary paths that led to the various forms of the vertebrate skeleton. For example, Pteraspidomorphs (stem-gnathostomes), such as the Ordovician Astraspis, display some of the oldest remains of bony and ‘dental’ tissues. However, the identification of the very natu...

Owing to their prevalence in nowadays terrestrial ecosystems, insects are a relevant group to assess the impact of mass extinctions on emerged land. However, limitations of the insect fossil record make it difficult to assess the impact of such events based on taxonomic diversity alone. Therefore, we documented trends in morphological diversity, i....

L’étude des tissus minéralisés des premiers vertébrés est essentielle pour mieux comprendre l’origine et l’évolution de notre squelette. Par exemple, les Ptéraspidomorphes (gnathostomes souches) présentent certains des plus anciens restes connus de tissus osseux et « dentaires ». Cependant, l’identification de ces tissus reste débattue en raison de...

Reptiles represent one of the most diverse groups of tetrapod vertebrates. Extant representatives of reptiles include lepidosaurs (lizards), testudines (turtles) and archosaurs (crocodiles and birds). In particular, they show an important locomotor diversity with bipedal, quadrupedal and facultatively bipedal taxa. This diversity is accompanied by...

Mammals have an evolutionary history spanning hundreds of millions of years. Today, mammals represent one of the most diverse groups of tetrapod vertebrates. In particular, they present a great postural diversity. The humerus adopts different positions: small mammals have a “crouched” posture with a quasi-horizontal humerus, while in the largest sp...

The chemical composition of the wood reflects the composition of the soil over which the corresponding tree has developed. Multi-elemental and isotopic signatures, which are characteristic of the soil and underlying rock substrates, are potentially powerful tools for determining wood provenance. These tracers are of special interest for charred arc...

The water‐to‐land transition by the first tetrapod vertebrates represents a key stage in their evolution. Selection pressures exerted by this new environment on animals led to the emergence of new locomotor and postural strategies that favoured access to different ecological niches and contributed to their evolutionary success. Today, amniotes show...

The study of morphological adaptations to different ecological parameters among fossil vertebrates has been an important challenge in recent decades. In this paper, we focus on the link between morphological traits and locomotor behavior such as terrestriality, fossoriality and arboreality (including gliding). One of the most diverse groups in whic...

Ancient charcoal fragments, produced by the use of wood as fuel in archaeological contexts or during natural or anthropic forest fires, persist in soil and sediments over centuries to millennia. They thus offer a unique window to reconstruct past climate, especially palaeo-precipitation regimes thanks to their stable carbon isotope composition. How...

Ancient charcoal fragments, produced by the use of wood as fuel in archaeological contexts or during natural or anthropic forest fires, persist in soil and sediments over centuries to millennia. They thus offer a unique window to reconstruct past climate, especially palaeo-precipitation regimes thanks to their stable carbon isotope composition. How...

Enamel and enameloid are hypermineralized tissues that can be found on the surface of vertebrates’ teeth and odontodes. Contrary to enamel, whose origin is exclusively epithelial, enameloid is characterized by a dual epithelial and mesenchymal origin. The earliest evidence of enamel are found in stem-osteichthyans from the Silurian, while enameloid...

A multi-proxy approach integrating data on planktonic foraminifera, calcareous nannofossils, δ13Ccarb, δ18Ocarb and the coiling direction of Muricohedbergella delrioensis was carried out for two sections in the Tellian Atlas (Algeria) both to establish a precise stratigraphic scheme and to precise the climatic events. The Sour el Ghozlane section...

The second-order Pliensbachian–Toarcian crisis affected major groups of marine organisms. While its impact has been intensively studied for ammonites, the response of belemnites is only currently emerging through quantitative studies. Novel overall and regional diversity analyses suggest that belemnite richness in the NW-Tethys drops at the Pliensb...

Probably the most common rock-imprint fossil-insect remain is an incomplete isolated wing. This pitfall has been traditionally addressed by manually reconstructing missing parts, which is not ideal to comprehend long-term evolutionary trends in the group, in particular for morphological diversity (i.e., disparity) approaches. Herein we describe a n...

The cecal appendix had been considered as a useless vestige since Darwin's work, but recent research questioned this idea demonstrating that the cecal appendix appeared among the mammals at least 80 million years ago and has made multiple and independent appearances without any obvious correlation with diet, social life, ecology, or size of the cec...

Ammonite soft body remains are rarely preserved. One of the biggest enigmas is the morphology of the ammonite brachial crown that has, up till now, never been recovered. Recently, mysterious hook-like structures have been reported in multiple specimens of Scaphitidae, a large family of heteromorph Late Cretaceous ammonites. A previous examination o...

The three-taxon statement is the fundamental unit of rooted trees in cladistics, stating that for three terminal taxa, two are more related to each other than to a third. Because of their fundamental role in phylogenetics, three-taxon statements are present in methodological research of various disciplines in evolutionary biology; for example conse...

Iterative segments such as teeth or limbs are a widespread characteristic of living organisms. While their proportions may be governed by similar developmental rules in vertebrates, there is no emerging pattern as regards their relation to size. Placental mammals span eight orders of magnitude in body size and show a wide spectrum of dietary habits...

A large part of extant and past mammalian morphological diversity is related to variation in size through allometric effects. Previous studies suggested that craniofacial allometry is the dominant pattern underlying mammalian skull shape variation, but cranial allometries were rarely characterized within cranial units such as individual bones. Here...

A bstract The three-taxon statement is the fundamental unit of rooted trees in Cladistics, stating that for three terminal taxa, two are more related to each other than to a third. Because of their fundamental role in phylogenetics, three-taxon statements are present in methodological research of various disciplines in evolutionary biology, as in c...

The practice of species delimitation using molecular data commonly leads to the revealing of species complexes and an increase in the number of delimited species. In a few instances, however, DNA-based taxonomy has led to lumping together of previously described species. Here, we delimit species in the genus Cryptogemma (Gastropoda: Conoidea: Turri...

The study of timber wood and wood charcoal fragments from archaeological sites (aka anthracology) constitutes a relevant archaeobotanical field of research for both landscape reconstruction and the study of past people-woodlands interactions. Regarding this second research field, variables other than taxa are known to be a key to the social organiz...

In the last few decades, hook‐like structures have been reported in the Mesozoic ammonite family Scaphitidae. Despite their exceptional preservation and debates about their function, no detailed reconstruction has been available until now. For the first time, we describe the composition and details of the morphology of these structures found in the...

High-resolution changes in the mineralogical assemblages at Pueblo and Hot Springs of the Western Interior Basin (WIB, USA) were investigated for the late Cenomanian–early Turonian interval, including the Oceanic Anoxic Event 2 (OAE2). The aim of this study is to investigate the regional significance of clay mineral assemblages in the WIB by distin...

The lifestyle of extinct tetrapods is often difficult to assess when clear morphological adaptations such as swimming paddles are absent. According to the hypothesis of bone functional adaptation, the architecture of trabecular bone adapts sensitively to physiological loadings. Previous studies have already shown a clear relation between trabecular...

Accurate modeling of the complexity of morphological evolution is crucial for morphological phylogenetics and for performing tests on a wide variety of evolutionary scenarios. In this context, morphological integration and the problem of correlated categorical characters represent a major challenge. In particular, the magnitude and implications of...

Ammonite phylogeny has mainly been established based on a stratigraphic approach, with cladistics underconsidered. The main arguments against the use of cladistics are the supposed large amount of homoplasy and the small number of characters. Resolving the phylogeny of the Hildoceratidae (Early Jurassic) is especially challenging because of its lar...

Palaeontological data are key elements for inferring ancestral character states and the assembly of character complexes, but cephalopod fossils preserving soft tissues are very rare. The exceptionally well-preserved, unique specimen of Jurassic Proteroctopus ribeti Fischer & Riou from the Lagerstätte of La-Voulte-sur-Rhône (c. 165 Ma, France) is on...

Ontogeny is rarely included in phylogenetic analyses of morphological data. When used, the ontogenetic information is reduced to one character for two or three different ontogenetic stages. Several examples show that current methods miss a major part of the information. We here propose a new method for including the ontogenetic dimension in coding...

Among some modern and recent fossil species of planktonic foraminifera, the proportion of left- to right-coiled shells in a population appears to be temperature-dependent; the relative abundance of each morphotype reflecting ecological preferences. A similar relationship is identified among Muricohedbergella delrioensis (Carsey, 1926) at the Cenoma...

Ammonite phylogeny has mainly been established based on a stratigraphic approach, with cladistics underconsidered. The main arguments against the use of cladistics are the supposed large amount of homoplasy and the small number of characters. Resolving the phylogeny of the Hildoceratidae (Early Jurassic) is especially challenging because of its lar...

Cladistics appears as one of the most useful method to reconstruct phylogeny of fossil taxa. However, ammonoids workers tend to sulk this method. The capital step of cladistic analysis is the recognition of homology hypothesis as clue to reconstruct monophyletic clades based on the sharing of derived traits. Previous authors have suggested that cod...

A rich ammonite fauna from the Lower Toarcian (Lower Jurassic) of the South Riffian ridges (northern Morocco), collected bed-by-bed from 14 new outcrops, is described. The fauna is nearly exclusively composed of already-known taxa, allowing correlation from the chronozone down to the zonule level. Fourteen species are described, among them the new...

Abstract: A belemnite fauna collected in the lowermost Toarcian succession which crops out near Moulay Idriss (northern Morocco) is studied in this paper. This is the first palaeontological study of Early Toarcian belemnites from Northern Africa, i.e. the north-eastern margin of the Gondwana, in connexion with Tethys. Four species of the family Pas...

Since the introduction of the cladistic method in systematics, continuous characters have been integrated into analyses but no methods for their treatment have received unanimous support. Some methods require a large number of character states to discretise continuous characters in order to keep the maximum level of information about taxa differenc...

The present paper deals with the systematic description of a rich and well-preserved ammonite fauna of the Late Pliensbachian, collected in two outcrops near the "Lac de Charmes" (Haute-Marne, France). In terms of ammonite zonation, the studied faunas indicate the Margaritatus and Spinatum Chronozones. Most of their subdivisions (subchronozones and...