Johannes Müller

• Professor at Museum für Naturkunde - Leibniz Institute for Research on Evolution and Biodiversity

The fossil record provides direct evidence for the behavior of biological systems over millions of years, offering a vital source for studying how ecosystems evolved and responded to major environmental changes. Using network analysis on a dataset of over 3000 fossil species spanning the past 60 Myr, we find that ungulate continental assemblages ex...

Tooth complexity has long been known as a powerful indicator of feeding in mammals and reptiles, often used to infer diets of long-extinct species. However, how these trends are established below the species level remains unclear. Here, we use Orientation Patch Count Rotated (OPCR) to quantify tooth complexity across eight populations of Podarcis p...

To investigate reptile body size as an ecological indicator and the relationships between size and environmental variables through time, we compared patterns of maximum size from the Plio-Pleistocene Shungura Formation of Ethiopia. For this previously-undescribed reptile fossil record, we provided estimates of body mass for pythonid snakes, aquatic...

Morphological traits of animals have evolved to solve ecological requirements, the optimization of locomotion in each environment being one of the most frequent selective forces shaping morphology. Amphisbaenians are strictly fossorial reptiles that have evolved various snout shapes for burrowing head‐first underground, yet the evolutionary and eco...

Comparisons of extant and extinct biodiversity are often dependent on objective morphology-based identifications of fossils and assume a well-established and comparable taxonomy for both fossil and modern taxa. However, since many modern (cryptic) species are delimitated mainly via external morphology and / or molecular data, it is often unclear to...

High-resolution computed tomography (HRCT) has become a widely used tool for studying the inner ear morphology of vertebrates. Amphisbaenians are one of the most specialized groups of fossorial reptiles but are poorly understood relative to other squamate reptile. In this paper we survey the anatomy of the inner and middle ear of these fossorial re...

Terrestrial carnivorans, with their diverse diets and unique adaptations such as the carnassial tooth, offer insights into the connections between functional traits and the climatic and environmental conditions they inhabit. They shed light on functional trait‐environment relationships at the highest trophic levels across a broad range of environme...

The fossil record provides direct evidence for the behavior of biological systems over millions of years. In doing so, paleontological information becomes a key source to study the evolution of ecosystems and how they responded to major environmental shifts. Using network analysis over a dataset of worldwide large herbivores spanning the past 60 My...

Background Snakebite is a major poverty-related neglected tropical disease. An integrated scientific approach is needed to understand the dynamics of this important health issue. Our objective was to estimate snakebite occurrence in a tropical area by using a blend of ecological modelling and robust statistical analysis. Methods The present study...

The skull anatomy of amphisbaenians directly influences their capacity to burrow and is crucial for the study of their systematics, which ultimately contributes to our comprehension of their evolution and ecology. In this study, we employed three-dimensional X-ray computed tomography to provide a detailed description and comprehensive comparison of...

The Arnstadt Formation of Saxony-Anhalt, Germany has yielded some of Germany’s most substantial finds of Late Triassic tetrapods, including the sauropodomorph Plateosaurus and the stem-turtle Proganochelys quenstedti. Here, we describe an almost complete skull of a new sphenodontian taxon from this formation (Norian, 227–208 Ma), making it the olde...

Billfish rostra potentially have several functions; however, their role in feeding is unequivocal in some species. Recent work linked morphological variation in rostral micro‐teeth to differences in feeding behavior in two billfish species, the striped marlin (Kajikia audax) and the sailfish (Istiophorus platypterus). Here, we present the rostral m...

Increasing urbanisation and intensified agriculture lead to rapid transitions of ecosystems. Species that persist throughout rapid transitions may respond to environmental changes across space and/or time, for instance by altering morphological and/or biochemical traits. We used natural history museum specimens, covering the Anthropocene epoch, to...

Mammalian megafauna have been critical to the functioning of Earth’s biosphere for millions of years. However, since the Plio-Pleistocene, their biodiversity has declined, concurrent with dramatic environmental change and hominin evolution. While these biodiversity declines are well-documented, their impacts on the ecological function of megafaunal...

Mammalian megafauna have been critical to the functioning of Earth’s biosphere for millions of years. However, since the Plio-Pleistocene, their biodiversity has declined concurrently with dramatic environmental change and hominin evolution. While these biodiversity declines are well-documented, their implications for the ecological function of meg...

Mammalian megafauna have been critical to the functioning of Earth’s biosphere for millions of years. However, since the Plio-Pleistocene, their biodiversity has declined, concurrent with dramatic environmental change and hominin evolution. While these biodiversity declines are well-documented, their impacts on the ecological function of megafaunal...

Understanding the relationships between functional traits and environment is increasingly important for assessing ecosystem health and forecasting biotic responses to future environmental change. Taxon-free analyses of functional traits (ecometrics) allow for testing the performance of such traits through time, utilizing both the fossil record and...

The late Quaternary is characterized by the extinction of many terrestrial megafauna, which included tortoises (Family: Testudinidae). However, limited information is available on how extinction shaped the phenotype of surviving taxa. Here, based on a global dataset of straight carapace length, we investigate the temporal variation, spatial distrib...

Mammalian megafauna have been critical to the functioning of Earth’s biosphere for millions of years. However, since the Plio-Pleistocene, their biodiversity has declined, concurrent with dramatic environmental change and hominin evolution. While these biodiversity declines are well-documented, their impacts on the ecological function of megafaunal...

Snakes are sensitive to both environmental and climate gradients. To design conservation plans, a scientific understanding of snake habitats in light of environmental and climatic variables is an essential prerequisite. For venomous snakes, denoting favourable habitats should also be relevant for snakebite management. We have considered 18 spatial...

Snakes comprise nearly 4,000 extant species found on all major continents except Antarctica. Morphologically and ecologically diverse, they include burrowing, arboreal, and marine forms, feeding on prey ranging from insects to large mammals. Snakes are strikingly different from their closest lizard relatives, and their origins and early diversifica...

East Africa is a global biodiversity hotspot and exhibits distinct longitudinal diversity gradients from west to east in freshwater fishes and forest mammals. The assembly of this exceptional biodiversity and the drivers behind diversity gradients remain poorly understood, with diversification often studied at local scales and less attention paid t...

Fluvial sediments of the middle Atbara River Valley, eastern Sudan, contain abundant vertebrate fossils and stone tools. Previous work described two sedimentary units, the Butana Bridge Synthem (BBS) and the Khashm El Girba Synthem (KGS), with three divisions each (BBS1-3 and KGS1-3, from bottom to top, respectively). ²³⁰Th/U dating on bivalve shel...

Recent comparative studies of billfishes (Istiophoridae and Xiphiidae) have provided evidence of differences in the form and function of the rostra (bill) among species. Here, we report the discovery of a new structure, lacuna rostralis, on the rostra of sailfish Istiophorus platypterus, which is absent on the rostra of swordfish Xiphias gladius, s...

The Quaternary Period is characterized by dramatic global climatic changes. Quaternary fossil deposits, which can offer excellent stratigraphic resolution, provide a unique opportunity to understand how fauna respond to past environmental change. Here, we test if the herpetofauna of McEachern’s Deathtrap Cave, a late Pleistocene to Holocene pitfall...

A small collection of isolated precloacal vertebrae from the late Miocene Baynunah Formation of the United Arab Emirates represents a herpetofauna with a minimum of eight species: an indeterminate anuran, an amphisbaenian, cf. Erycidae indet., Python sp., three indeterminate colubroid vertebral morphs, and Viperidae indet. The overall faunal compos...

Understanding the genomic basis of adaptation to different abiotic environments is important in the context of climate change and resulting short‐term environmental fluctuations. Using functional and comparative genomics approaches, we here investigated whether signatures of genomic adaptation to a set of environmental parameters are concentrated i...

Asian cobras (genus Naja ) are venomous snakes distributed from the Middle East to Southeast Asia. Because cobras often live near humans settlements, they are responsible for a large part of snakebite incidents and as such pose a challenge for public health systems. In the light of growing human populations, correctly mapping the present and future...

Since the 19th century, the addax (Addax nasomaculatus) has lost approximately 99% of its former range. Along with its close relatives, the blue antelope (Hippotragus leucophaeus) and the scimitar-horned oryx (Oryx dammah), the addax may be the third large African mammal species to go extinct in the wild in recent times. Despite this, the evolution...

Here we report on a new dyrosaurid from the latest Cretaceous Kababish Formation, Sudan, which was previously unknown to yield fossil macrovertebrates and had remained largely unstudied. The almost complete, partially articulated skeleton was recovered in situ near Jebel Abyad. The skeleton is almost 7 m in length and preserves an almost complete s...

Increasing artificial illumination during night has multifaceted effects on species. Moths are shown to be distracted and attracted by artificial light sources, leading to increased mortality through predation or exhaustion. Increased mortality can be expected to increase selection pressure on morphology, particularly those being functional in ligh...

Paleontology for conservation Human activities are leading to broad species and system declines. Prevention of such declines has led us to focus on either protection for species or protection for ecosystem function. Looking at past patterns of species and system change can help to inform our understanding of the long-term impacts of these strategie...

Climate has a large impact on diversity and evolution of the world’s biota. The Eocene–Oligocene transition from tropical climate to cooler, drier environments was accompanied by global species turnover. A large number of Old World lacertid lizard lineages have diversified after the Eocene–Oligocene boundary. One of the most speciose reptile genera...

Climate has a large impact on diversity and evolution of the world’s biota. The Eocene–Oligocene transition from tropical climate to cooler, drier environments was accompanied by global species turnover. A large number of Old World lacertid lizard lineages have diversified after the Eocene– Oligocene boundary. One of the most speciose reptile gener...

Based on its mandibular gland secretion, the earless monitor lizard, Lanthanotus borneensis, has been considered a venomous animal like other members of the Toxicofera group, including Heloderma. In the present study, the gland structure and teeth of L. borneensis were examined by micro-tomography (μCT) and scanning electron microscopy (SEM), respe...

𝗕𝗮𝗰𝗸𝗴𝗿𝗼𝘂𝗻𝗱. The study of convergently acquired adaptations allows fundamental insight into life's evolutionary history. Within lepidosaur reptiles – i.e., lizards, tuatara, and snakes – a fully fossorial ('burrowing') lifestyle has independently evolved in most major clades. However, despite their con-sistent use of the skull as a digging tool, cra...

Despite growing pressure on biodiversity deriving from increasing anthropogenic disturbances, some species successfully persist in altered ecosystems. However, these species' characteristics and thresholds, as well as the environmental frame behind that process are usually unknown. We collected data on body size, fluctuating asymmetry (FA), as well...

The repeated evolution of convergent or analogous traits is often used as evidence for adaptive evolution. Squamate reptiles show a high degree of convergence in a variety of morphological traits; however, the evolutionary mechanisms driving these patterns are not fully understood. Here, we investigate the evolution of tail spines, a trait that evo...

Natural history museums are unique spaces for interdisciplinary research and educational innovation. Through extensive exhibits and public programming and by hosting rich communities of amateurs, students, and researchers at all stages of their careers, they can provide a place-based window to focus on integration of science and discovery, as well...

Increasing anthropogenic environmental impacts lead to rapid transitions of ecosystems and species. Species persisting in changing environments may respond to changes by altering phenotypic traits across space and/or time. Here we tested whether the frequencies of three color morphs in the ground beetle Harpalus affinis differed across spatial and...

Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and strip...

The acquisition of a fossorial lifestyle in squamates provides an excellent framework to study convergent evolution. In that context, the gross morphology of the skull in these head-first-burrowers has been the subject of several studies. However, to our knowledge, the inner structure of the cranial bones has never been quantified. We here test whe...

The acquisition of a fossorial lifestyle in squamates provides an excellent framework to study convergent evolution. In that context, the gross morphology of the skull in these head-first-burrowers has been the subject of several studies. However, to our knowledge, the inner structure of the cranial bones has never been quantified. We here test whe...

Background The evolution of elongated body forms in tetrapods has a strong influence on the musculoskeletal system, including the reduction of pelvic and pectoral girdles, as well as the limbs. However, despite extensive research in this area it still remains unknown how muscles within and around bony girdles are affected by these reductions. Here...

Fossoriality has been acquired repeatedly in the evolutionary history of squamates (e.g., worm lizards, sand skinks, hog-nosed snakes). Related to this case of convergent evolution, the gross morphology of the skull in the corresponding fossorial clades has been subject of numerous studies. Indeed, these clades mostly comprise head-first-burrowers,...

Global change has complex eco-evolutionary consequences for organisms and ecosystems, but related concepts (e.g., novel ecosystems) do not cover their full range. Here we propose an umbrella concept of “ecological novelty” comprising (1) a site-specific and (2) an organismcentered, eco-evolutionary perspective. Under this umbrella, complementary op...

Climatic conditions changing over time and space shape the evolution of organisms at multiple levels, including temperate lizards in the family Lacertidae. Here we reconstruct a dated phylogenetic tree of 262 lacertid species based on a supermatrix relying on novel phylogenomic datasets and fossil calibrations. Diversification of lacertids was acco...

Understanding the genomic basis of adaptation to different abiotic environments is important for understanding organismal responses to current short-term environmental fluctuations. Using functional and comparative genomics approaches, we here investigated whether genomic adaptation to a set of environmental parameters is contingent across vertebra...

Vertebrate ecology has been successfully inferred from bone microstructure in the past, but a systematic approach to quantify differences of the inner bone structure in the skull of squamate reptiles, i.e., lizards and snakes, has never been undertaken. In head-first-burrowing squamates, for example, the cranium is the structure exposed to the grea...

Our current understanding of form and function of the structures employed for vocalization in Testudines remains notably limited. To gain insight into their possible interactions, we carried out μCT-scans on the larynx of Testudo horsfieldii (Testudinidae) and Emys orbicularis (Emydidae), which serve as examples of the two turtle clades with the gr...

Significance With >10,000 living species, squamate reptiles (lizards, snakes) exhibit enormous phenotypic variation reflecting their incredible range in ecology and developmental strategies. What drove this exceptional diversity? We analyze high-density surface morphometric data for skulls representing ∼200 modern and extinct species to provide a c...

Rhynchosauria is a group of archosauromorph reptiles abundant in terrestrial ecosystems of the Middle Triassic. Mesosuchus is one of the earliest and basalmost rhynchosaurs, playing an important role not only for the understanding of the evolution of the group as a whole, but also of archosauromorphs in general. The braincase of Mesosuchus has been...

Natural history museums are unique spaces for interdisciplinary research and for educational innovation. Through extensive exhibits and public programming and by hosting rich communities of amateurs, students, and researchers at all stages of their careers, they provide a place-based window to focus on integration of science and discovery, as well...

Natural history museums are unique spaces for interdisciplinary research and for educational innovation. Through extensive exhibits and public programming and by hosting rich communities of amateurs, students, and researchers at all stages of their careers, they provide a place-based window to focus on integration of science and discovery, as well...

Developmental instability provides a powerful monitoring tool to detect threats prior to population declines. Consequently, assessing the level of developmental instability by measuring fluctuating asymmetry (FA) of bilaterally symmetrical traits in association with environmental stress has become increasingly attractive. However, many studies fail...

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Worm lizards, or amphisbaenians, of the genus Blanus are found in various countries around the Mediterranean Sea. In addition to four extinct species, seven extant taxa are currently recognized. Here, we present the first comparative analysis of the cranial osteology of Blanus including all extant species. The results of this analysis show a homoge...

Despite extensive research on ecological community compositions, general patterns across large-scale environmental gradients have remained unclear. A widely used explanatory model is the stress dominance hypothesis (SDH), predicting that the relative influence of environmental filtering is greater in stressful habitats while competition is more imp...

We describe the first record of a fossil gekkotan from the Late Oligocene Nsungwe Formation in the Rukwa Rift Basin, Tanzania. The specimen consists of an almost complete maxilla containing 23 tooth positions, with 10 teeth still in place. Typical gekkotan features include the tall facial process along with a posteriorly sloping angle, and the pres...

The squamate fossil record from Kanapoi reveals generic to higher-order similarities with modern East African herpetofaunas. The record is derived from surface collection and screen washing, and consists primarily of isolated vertebrae with a few maxillary and mandibular elements. The most abundant remains are vertebrae of large-bodied Python that...

Sensory perception is of crucial importance for animals to interact with their biotic and abiotic environment. In amniotes, the clade including modern mammals (Synapsida), modern reptiles (Reptilia), and their fossil relatives, the evolution of sensory perception took place in a stepwise manner after amniotes appeared in the Carboniferous. Fossil e...

The anatomy of African lacertid lizards (Lacertidae: Eremiadini) is poorly known, which has hindered a better understanding of their evolutionary relationships. This applies especially to the East African clade, which includes the genera Nucras, Latastia, Philochortus, Pseuderemias and Heliobolus. We present a detailed description of the skull oste...

The US and Mexico share a common history in many areas, including language and culture. They face ecological changes due to the increased frequency and severity of droughts and rising energy demands; trends that entail economic costs for both nations and major implications for human well being. We describe an ongoing effort by the Environment Worki...

The ecological origin of snakes remains amongst the most controversial topics in evolution, with three competing hypotheses: fossorial; marine; or terrestrial. Here we use a geometric morphometric approach integrating ecological, phylogenetic, paleontological, and developmental data for building models of skull shape and size evolution and developm...

The best-preserved material of Dracaenosaurus croizeti, an almost complete and previously unpublished skull with a few associated postcranial bones (stylopodium, zeugopodium, and cervical vertebra), is described. The material comes from the locality of Cournon, a late Oligocene site in south-central France. Micro-computed tomography applied to this...

Knowledge of the thermal ecology of a species can improve model predictions for temperature-induced population collapse, which in light of climate change is increasingly important for species with limited distributions. Here, we use a multi-faceted approach to quantify and integrate the thermal ecology, properties of the thermal habitat, and past a...

During early development of turtles and other amniotes, the parabasisphenoid, or basisphenoid s.l., is formed by at least two centers of ossification: the endochondral basisphenoid s.s. and the dermal parasphenoid. This fusion is usually so dramatic that the two elements cannot be distinguished from each other in the adult stage. Here we describe t...

During early development of turtles and other amniotes, the parabasisphenoid, or basisphenoid s.l., is formed by at least two centers of ossification: the endochondral basisphenoid s.s. and the dermal parasphenoid. This fusion is usually so dramatic that the two elements cannot be distinguished from each other in the adult stage. Here we describe t...

It is generally assumed that ectothermic vertebrates show a reversed Bergmann's cline, but several studies suggest the opposite for turtles. Here, we assess this issue using the widely distributed European pond turtle (Emys orbicularis), which displays strong geographic size variation. We tested carapace lengths of more than 2000 individuals from t...

Within the genus Pedioplanis the two basal species P. laticeps and P. burchelli are phenotypically similar. In this study we examine material of both species to determine diagnostic characters and we revise the distribution of Pedioplanis laticeps. For this we used data from museum collections, literature records, as well as results from our own su...

Recent climate change should result in expansion of species to northern or high elevation range margins,

Recent climate change should result in expansion of species to northern or high elevation range margins, and contraction at southern and low elevation margins in the northern hemisphere, because of local extirpations or range shifts or both. We combined museum occurrence records from both the continental U.S. and Mexico with a new eco-physiological...

Recent climate change should result in expansion of species to northern or high elevation range margins, and contraction at southern and low elevation margins due to extinction. Climate models predict dramatic extinctions and distributional shifts in the next century, but there are few ground-truths of these dire forecasts leading to uncertainty in...