Evolutionary Origin Research Articles

Multiple-resistance evolution to ACCase inhibitors and glyphosate in sourgrass (Digitaria insularis) is attributed to diverse polymorphisms in the herbicide target sites

Abstract Sourgrass [Digitaria insularis (L.) Mez ex Ekman] is considered the most troublesome weed in agronomic crops in South America. Overreliance on glyphosate has selected for resistant populations, although the resistance mechanisms remain unknown. Recently, populations were identified that exhibited multiple resistance to 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) and acetyl-CoA carboxylase (ACCase) inhibitors, posing a significant challenge due to the lack of alternative control options. This project aimed to identify the resistance patterns and levels to glyphosate and ACCase inhibitors of three suspected resistant populations (P1, P2, and P3), and elucidate the resistance mechanisms. We performed dose–response experiments with clethodim, fluazifop-P-butyl, glyphosate, and pinoxaden to identify the possibility of cross- and multiple resistance and to quantify the resistance levels. We sequenced the ACCase and EPSPS genes to test the hypothesis that target-site mutations were involved in the resistance mechanisms, given the resistance patterns observed. Our results indicated that two of the tested populations, P1 and P2, were multiple resistant to glyphosate and all ACCase-inhibitor classes, while P3 was resistant to glyphosate only. Resistance levels varied by herbicide, with resistance indices ranging from 2.7- to nearly 2,000-fold. We identified an amino acid substitution in ACCase at position 2078 (Asp-2078-Gly), homozygous for both P1 and P2, corroborating the resistance patterns observed. Interestingly, EPSPS sequencing identified multiple heterozygous DNA polymorphisms that resulted in amino acid substitutions at positions 106 (P1 and P2) or at both 102 and 106 (P3), indicating multiple evolutionary origins of glyphosate-resistance evolution. We show for the first time the genetic mechanisms of multiple resistance to glyphosate and ACCase in D. insularis, and provide a thorough discussion of the evolutionary and management implications of our work.

Aboriginal Australian weapons and human efficiency

Aggression—and its role in human societal development—continues to be hotly debated within both the sciences and the humanities. Whatever the evolutionary origins and repercussions of interpersonal and intergroup conflict for the human story, cultures around the globe have invested significant time and effort into designing deadly hand-held weaponry. Here, we describe for the first time, how humans deliver a deadly strike using two iconic and widespread Aboriginal Australian weapons: the kodj and the leangle with parrying shield. We present the world’s first evaluation of striking biomechanics and human and weapon efficiency regarding this class of implement. Results demonstrate the leangle is far more effective at delivering devastating blows to the human body, while the kodj—a multi-functional tool—is more efficient for a human to manoeuvre and still capable of delivering severe blows that can cause death. Together, these data provide the beginnings of an in-depth understanding of how hand-held weaponry has impacted the human body throughout the deep past.

The protamines of the spider Steatoda sp. provide an example of liquid-liquid phase separation chromatin transitions during spermiogenesis.

While there is extensive information about sperm nuclear basic proteins (SNBP) in vertebrates, there is by comparison, very little information in Arthropoda. This paper aims to contribute to filling this gap by analyzing these proteins in the sperm of the noble false widow spider Steatoda nobilis (Order Araneae, Family Theridiidae). To this end, we have developed a protein extraction method that allows the extraction of both cysteine-containing and non-Cysteine-containing protamines that is suitable for the preparation and analysis of SNBPs from samples where the amount of starting tissue material is limited. We carried out top-down mass spectrometry sequencing and molecular phylogenetic analyses to characterize the protamines of S. nobilis and other spiders. We also used electron microscopy to analyse the chromatin organization of the Steatoda sperm and we found it to exhibit liquid-liquid phase spinodal decomposition during the late stages of spermiogenesis. These studies further our knowledge on the distribution of SNBPs within the animal kingdom and provide additional support for a proposed evolutionary origin of many protamines from a histone H1 (H5) replication independent precursor.

Whole-chromosome oligo-painting in licorice unveils interspecific chromosomal evolutionary relationships and possible origin of triploid genome species.

Licorice is one of the most extensively studied medicinal plants in the world, whose roots and rhizomes have long been used as both a sweetener and an essential component in numerous herbal preparations. However, the genus Glycyrrhiza has a complex composition, and the interspecies chromosomal relationships, origin, and evolution are still largely unclear. Here, we develop a set of whole-chromosome painting probes that allowed identification of all eight chromosomes of licorice on same metaphase chromosomes. Comparative chromosome painting analyses in seven different Glycyrrhiza species revealed that the genus Glycyrrhiza maintained extraordinarily conserved chromosomal synteny after about 3-12 million years of divergence. No cytologically visible inter-chromosomal rearrangements were identified in any species. By comparative chromosomal karyotype analyses, we revealed interspecific chromosome evolutionary relationships and dramatic variable chromosomal karyotype after independent divergence and demonstrated that G. prostrate was the most closely related to the ancestral type among the seven Glycyrrhiza species. Furthermore, we also discovered a G. glandulosa seed with distinct triploid-genome for the first time in China, suggesting the existence of a polyploid evolutionary pathway in the genus Glycyrrhiza, which challenges the previous notion that only diploids of licorice existed in nature. This study expands our knowledge of the chromosome evolution of licorice and will lay an important foundation for the genome origin and evolution studies in the genus Glycyrrhiza.

Chloroplast genome sequencing and divergence analysis of 18 Pyrus species: insights into intron length polymorphisms and evolutionary processes

Pears constitute an essential temperate crop and are primarily produced through interspecific hybridization owing to self-incompatibility that complicates their breeding history. To address this, we sequenced the complete chloroplast (cp) genomes of 18 Pyrus and one Malus species using the Illumina HiSeq4000 platform. The cp genomes ranged from 159,885 bp to 160,153 bp and exhibited a conserved circular DNA structure with an average GC content of 36.5%. Each cp genome contained 127 genes, including 83 protein-coding, 36 tRNA, and 8 rRNA genes. Divergence analysis with mVISTA showed high conservation in the coding regions and notable variations in the non-coding regions. All species shared 17 intron-containing genes, with ycf3 and clpP each having two introns. Five intron-containing genes (ndhB, rpl2, rps12, trnA-UGC, and trnE-UUC) were located in the inverted repeat regions, while trnL-UAA was located in the large single-copy region, with conserved intron lengths across Pomoideae. We identified polymorphic intron sequences in the rpl22, petB, clpP, ndhA, and rps16 genes and designed primers for these regions. Notably, the two Pyrus ussuriensis accessions Doonggeullebae and Cheongdangrori showed intron-length polymorphisms despite being classified as the same species. Phylogenetic analysis of the cp genome sequences revealed two major clusters, indicating distinct maternal lineages and evolutionary origins. This study underscores the importance of cp gene polymorphisms in P. fauriei, P. calleryana, P. ussuriensis, and P. pyrifolia, providing valuable insights into Pyrus evolution as well as aiding in the conservation and breeding of pear germplasm.

Neural crest lineage in the protovertebrate model Ciona.

Neural crest cells are multipotent progenitors that produce defining features of vertebrates such as the 'new head'1. Here we use the tunicate, Ciona, to explore the evolutionary origins of neural crest since this invertebrate chordate is among the closest living relatives of vertebrates2-4. Previous studies identified two potential neural crest cell types in Ciona, sensory pigment cells and bipolar tail neurons5,6. Recent findings suggest that bipolartail neurons are homologous to cranial sensory ganglia rather than derivatives of neural crest7,8. Here we show that the pigment cell lineage also produces neural progenitor cells that form regions of the juvenile nervous system following metamorphosis. Neural progenitors are also a major derivative of neural crest in vertebrates, suggesting that the last common ancestor of tunicates and vertebrates contained a multipotent progenitor population at the neural plate border. It would therefore appear that a key property of neural crest, multipotentiality, preceded the emergence of vertebrates.

The cryptonephridial/rectal complex: an evolutionary adaptation for water and ion conservation.

Arthropods have integrated digestive and renal systems, which function to acquire and maintain homeostatically the substances they require for survival. The cryptonephridial complex (CNC) is an evolutionary novelty in which the renal organs and gut have been dramatically reorganised. Parts of the renal or Malpighian tubules (MpTs) form a close association with the surface of the rectum, and are surrounded by a novel tissue, the perinephric membrane, which acts to insulate the system from the haemolymph and thus allows tight regulation of ions and water into and out of the CNC. The CNC can reclaim water and solutes from the rectal contents and recycle these back into the haemolymph. Fluid flow in the MpTs runs counter to flow within the rectum. It is this countercurrent arrangement that underpins its powerful recycling capabilities, and represents one of the most efficient water conservation mechanisms in nature. CNCs appear to have evolved multiple times, and are present in some of the largest and most evolutionarily successful insect groups including the larvae of most Lepidoptera and in a major beetle lineage (Cucujiformia + Bostrichoidea), suggesting that the CNC is an important adaptation. Here we review the knowledge of this remarkable organ system gained over the past 200 years. We first focus on the CNCs of tenebrionid beetles, for which we have an in-depth understanding from physiological, structural and ultrastructural studies (primarily in Tenebrio molitor), which are now being extended by studies in Tribolium castaneum enabled by advances in molecular and microscopy approaches established for this species. These recent studies are beginning to illuminate CNC development, physiology and endocrine control. We then take a broader view of arthropod CNCs, phylogenetically mapping their reported occurrence to assess their distribution and likely evolutionary origins. We explore CNCs from an ecological viewpoint, put forward evidence that CNCs may primarily be adaptations for facing the challenges of larval life, and argue that their loss in many aquatic species could point to a primary function in conserving water in terrestrial species. Finally, by considering the functions of renal and digestive epithelia in insects lacking CNCs, as well as the typical architecture of these organs in relation to one another, we propose that ancestral features of these organs predispose them for the evolution of CNCs.

Aeromonas and mcr–3: A Critical Juncture for Transferable Polymyxin Resistance in Gram-Negative Bacteria

Polymyxin antibiotics B and colistin are considered drugs of last resort for the treatment of multi-drug and carbapenem-resistant Gram-negative bacteria. With the emergence and dissemination of multi-drug resistance, monitoring the use and resistance to polymyxins imparted by mobilised colistin resistance genes (mcr) is becoming increasingly important. The Aeromonas genus is widely disseminated throughout the environment and serves as a reservoir of mcr–3, posing a significant risk for the spread of resistance to polymyxins. Recent phylogenetic studies and the identification of insertion elements associated with mcr–3 support the notion that Aeromonas spp. may be the evolutionary origin of the resistance gene. Furthermore, mcr–3-related genes have been shown to impart resistance in naïve E. coli and can increase the polymyxin MIC by up to 64-fold (with an MIC of 64 mg/L) in members of Aeromonas spp. This review will describe the genetic background of the mcr gene, the epidemiology of mcr-positive isolates, and the relationship between intrinsic and transferable mcr resistance genes, focusing on mcr–3 and mcr–3-related genes.

Origin of division of labor is decoupled from polymorphism in colonial animals

Abstract Division of labor, the specialization of sometimes phenotypically divergent cell types or group members, is often associated with ecological success in eukaryotic colonial organisms. Despite its many independent evolutionary origins, how division of labor emerges remains unclear. Conventional hypotheses tend towards an “economic” model, so that biological division of labor may reflect a partitioning of pre-existing tasks and morphologies into specialized colony members. Here, we present an alternative model of the origin of division of labor, which can explain the evolution of new functions within a colony. We show that in colonies of the Cretaceous aged (103-96 Ma) fossil bryozoan of the genus Wilbertopora, the first cheilostome bryozoan to evolve polymorphism, pre-extinction morphologies were not simply partitioned among new members, but instead expanded into novel morphospace as they lost functions, specifically feeding. This expansion occurred primarily during two pulses of heightened morphological disparity, suggesting that the evolution of polymorphism corresponded to relaxed constraints on morphology and perhaps to the exploration of novel functions. Using a simple model of physiological connections, we show that regardless of the functionality of these new colony members, all non-feeding members could have been supported by neighboring feeding members. This suggests that the geometric constraints and physiological connectedness could be prerequisites for evolving both polymorphism and division of labor in modular organisms, and that a classic partitioning model of specialization cannot be broadly applied to biological systems.

Cultural, Cognitive, and Ecological Dynamics of Individual Religiosity

In the following, I consider how to better link the study of cognition and behavior to the evolutionary origins of cognitive mechanisms, within the framework of embodied cognition theory. Specifically, I attempt to show this by examining the topic of individual commitment, its origins, and its relationship to beliefs and identity. I then go on to point out that the way we talk about cognition and cognitive processes can be misleading, and although we cannot dispense with the use of metaphorical language, it might be worth considering some of the shortcomings of the metaphors in order to rid ourselves of misconceptions.

Evolutionary origins of the lysosome-related organelle sorting machinery reveal ancient homology in post-endosome trafficking pathways

The major organelles of the endomembrane system were in place by the time of the last eukaryotic common ancestor (LECA) (~1.5 billion years ago). Their acquisitions were defining milestones during eukaryogenesis. Comparative cell biology and evolutionary analyses show multiple instances of homology in the protein machinery controlling distinct interorganelle trafficking routes. Resolving these homologous relationships allows us to explore processes underlying the emergence of additional, distinct cellular compartments, infer ancestral states predating LECA, and explore the process of eukaryogenesis itself. Here, we undertake a molecular evolutionary analysis (including providing a transcriptome of the jakobid flagellate Reclinomonas americana), exploring the origins of the machinery responsible for the biogenesis of lysosome-related organelles (LROs), the Biogenesis of LRO Complexes (BLOCs 1,2, and 3). This pathway has been studied only in animals and is not considered a feature of the basic eukaryotic cell plan. We show that this machinery is present across the eukaryotic tree of life and was likely in place prior to LECA, making it an underappreciated facet of eukaryotic cellular organisation. Moreover, we resolve multiple points of ancient homology between all three BLOCs and other post-endosomal retrograde trafficking machinery (BORC, CCZ1 and MON1 proteins, and an unexpected relationship with the "homotypic fusion and vacuole protein sorting" (HOPS) and "Class C core vacuole/endosomal tethering" (CORVET) complexes), offering a mechanistic and evolutionary unification of these trafficking pathways. Overall, this study provides a comprehensive account of the rise of the LROs biogenesis machinery from before the LECA to current eukaryotic diversity, integrating it into the larger mechanistic framework describing endomembrane evolution.

Viruses and Mitochondrial Dysfunction in Neurodegeneration and Cognition: An Evolutionary Perspective

Mitochondria, the cellular powerhouses with bacterial evolutionary origins, play a pivotal role in maintaining neuronal function and cognitive health. Several viruses have developed sophisticated mechanisms to target and disrupt mitochondrial function which contribute to cognitive decline and neurodegeneration. The interplay between viruses and mitochondria might be traced to their co-evolutionary history with bacteria and may reflect ancient interactions that have shaped modern mitochondrial biology.

Ancient secretory pathways contributed to the evolutionary origin of an ecologically impactful bioluminescence system.

Evolutionary innovations in chemical secretion - such as the production of secondary metabolites, pheromones, and toxins - profoundly impact ecological interactions across a broad diversity of life. These secretory innovations may involve a "legacy-plus-innovation" mode of evolution, whereby new biochemical pathways are integrated with conserved secretory processes to create novel products. Among secretory innovations, bioluminescence is important because it evolved convergently many times to influence predator-prey interactions, while often producing courtship signals linked to increased rates of speciation. However, whether or not deeply conserved secretory genes are used in secretory bioluminescence remains unexplored. Here, we show that in the ostracod Vargula tsujii, the evolutionary novel c-luciferase gene is co-expressed with many conserved genes, including those related to toxin production and high-output protein secretion. Our results demonstrate that the legacy-plus-innovation mode of secretory evolution, previously applied to sensory modalities of olfaction, gustation, and nociception, also encompasses light-producing signals generated by bioluminescent secretions. This extension broadens the paradigm of secretory diversification to include not only chemical signals but also bioluminescent light as an important medium of ecological interaction and evolutionary innovation.

The evolutionary origin of human kissing.

A kiss has been a signal of special affection across continents and cultures for millennia. Between times and peoples, social norms invariably prescribe kissing to specific affiliations and contexts, implying deeper biological bases. Why the protruding of the lips and slight suction when touching another? Capuchin monkeys stick their fingers in their friends' eyes as sign of affection, why have humans developed kissing? Here I briefly review proposed hypotheses for the evolution of human kissing. Great ape social behavior suggests that kissing is likely the conserved final mouth-contact stage of a grooming bout when the groomer sucks with protruded lips the fur or skin of the groomed to latch on debris or a parasite. The hygienic relevance of grooming decreased over human evolution due to fur-loss, but shorter sessions would have predictably retained a final "kissing" stage, ultimately, remaining the only vestige of a once ritualistic behavior for signaling and strengthening social and kinship ties in an ancestral ape.

Identification of shared gene expression programs activated in multiple modes of torpor across vertebrate clades

Torpor encompasses diverse adaptations to extreme environmental stressors such as hibernation, aestivation, brumation, and daily torpor. Here we introduce StrokeofGenus, an analytic pipeline that identifies distinct transcriptomic states and shared gene expression patterns across studies, tissues, and species. We use StrokeofGenus to study multiple and diverse forms of torpor from publicly-available RNA-seq datasets that span eight species and two classes. We identify three transcriptionally distinct states during the cycle of heterothermia: euthermia, torpor, and interbout arousal. We also identify torpor-specific gene expression patterns that are shared both across tissues and between species with over three hundred million years of evolutionary divergence. We further demonstrate the general sharing of gene expression patterns in multiple forms of torpor, implying a common evolutionary origin for this process. Although here we apply StrokeofGenus to analysis of torpor, it can be used to interrogate any other complex physiological processes defined by transient transcriptomic states.

Evolutionary origins, macroevolutionary dynamics, and climatic niche space of the succulent plant syndrome in the Caryophyllales.

The succulent plant syndrome is defined by the coordination of traits that enhance internal water storage within plant tissues. Although distributed globally in different habitats, succulent plants are thought to have evolved to avoid drought in arid regions, due to trait modifications that decrease tissue water deficits. We evaluated the evolution and the ecological significance of the succulent strategy at a global scale by comparing the climatic niche of species displaying succulence within the Core Caryophyllales with their non-succulent relatives. We assembled and curated a worldwide dataset of 201K georeferenced records belonging to 5447 species within 28 families, and analyzed the climatic niche of species along with their origin and evolutionary trajectories using ecological niche modeling, phylogenetic regression, divergence dates and ancestral state estimation. Results indicate the Core Caryophyllales have inhabited drylands since their origin in the Early Cretaceous. However, the succulent syndrome appeared and diversified during later geologic periods. The climatic niche space of succulents is narrower than non-succulent relatives, but no climate niche separation was detected between groups. Our results support alternative interpretations on the environmental and ecological forces that spurred the origin and diversification of the succulent plant syndrome and the radiation of rich succulent lineages.

To know or not to know? Curiosity and the value of prospective information in animals.

Humans and other animals often seek instrumental information to strategically improve their decisions in the present. Our curiosity also leads us to acquire non-instrumental information that is not immediately useful but can be encoded in memory and stored for use in the future by means of episodic recall. Despite its adaptive benefits and central role in human cognition, questions remain about the cognitive mechanisms and evolutionary origins that underpin curiosity. Here, we comparatively review recent empirical studies that some authors have suggested reflects curiosity in nonhuman animals. We focus on findings from laboratory tasks in which individuals can choose to gain advanced information about uncertain future outcomes, even though the information cannot be used to increase future rewards and is often costly. We explore the prevalence of preferences in these tasks across animals, discuss the theoretical advances that they have promoted, and outline some limitations in contemporary research. We also discuss several features of human curiosity that can guide future empirical research aimed at characterising and understanding curiosity in animals. Though the prevalence of curiosity in animals is actively debated, we surmise that investigating behavioural candidates for curiosity-motivated behaviour in a broader range of species and contexts, should help promote theoretical advances in our understanding of cognitive principles and evolutionary pressures that support curiosity-driven behaviour.

Bottleneck Effect Analysis in Indigenous Poonchi Chicken Located Near International Border of India and Pakistan

Background: Poonch is the remotest district of Jammu, India located near to line of control with Pakistan. Poonchi chicken is the first native poultry breed of Jammu region which is being characterized and registered with National Bureau of Animal Genetic Resources. Present study is the first study on genetic bottleneck assessment in Poonchi chicken population using recommended microsatellite markers. This study in Poonchi chicken would be of immense use in tracing evolutionary origin and formulating effective conservation strategies for genetic diversity within breeds. Methods: Blood samples were collected randomly from Poonch and Rajouri districts of Jammu for DNA extraction and analysis. Microsatellite markers selected for the analysis were ADL0268, MCW0206, MCW0081, ADL0278, MCW0069, MCW0248, MCW0111, MCW0222, MCW0016 and LEI0094. To evaluate the Poonchi chicken for mutation drift equilibrium, Bottleneck software was used. Infinite allele model (IAM), two phase model of mutation (TPM) and stepwise mutation model (SMM) tests were done. Mode shift test was also used as another method of qualitative test for allele frequency. Result: Total number of alleles observed were 72, with the total number alleles ranged from 6 to 9. The results of all three models (IAM, TPM, SMM) in Sign test depicted the heterozygosity was more in the expected number of loci in Poonchi chicken as 5.97 (P less than 0.05), 5.93 (P less than 0.05), 5.90 (P less than 0.05) respectively. Whereas for Wilcoxon rank test the IAM, TPM and SMM revealed significant values of (P less than 0.05) deviation indicating that all the loci deviate from mutation-drift equilibrium. Mode shift test graph obtained depicted a slight shift from normal L-shaped curve indicating recent bottleneck effect in Poonchi chicken. This might have resulted in the loss of number of effective alleles which suggests a need of planning and implementing an effective breeding policy in order to preserve and promote this native breed.

New soft tissue data of pterosaur tail vane reveals sophisticated, dynamic tensioning usage and expands its evolutionary origins.

Pterosaurs were the first vertebrates to achieve powered flight. Early pterosaurs had long stiff tails with a mobile base that could shift their center of mass, potentially benefiting flight control. These tails ended in a tall, thin soft tissue vane that would compromise aerodynamic control and efficiency if it fluttered during flight like a flag in the wind. Maintaining stiffness in the vane would have been crucial in early pterosaur flight, but how this was achieved has been unclear, especially since vanes were lost in later pterosaurs and are absent in birds and bats. Here we use Laser-Stimulated Fluorescence imaging to reveal a cross-linking lattice within the tail vanes of early pterosaurs. The lattice supported a sophisticated dynamic tensioning system used to maintain vane stiffness, allowing the whole tail to augment flight control and the vane to function as a display structure.

A small venomous reptile from the Late Triassic (Norian) of the southwestern United States.

Reptile feeding strategies encompass a wide variety of diets and accompanying diversity in methods for subduing prey. One such strategy, the use of venom for prey capture, is found in living reptile clades like helodermatid (beaded) lizards and some groups of snakes, and venom secreting glands are also present in some monitor lizards and iguanians. The fossil record of some of these groups shows strong evidence for venom use, and this feeding strategy also has been hypothesized for a variety of extinct reptiles (e.g., archosauromorphs, anguimorphs, and a sphenodontian). However, evidence of systems for venom delivery in extinct groups and its evolutionary origins has been scarce, especially when based on more than isolated teeth. Here, we describe a potentially venomous new reptile, Microzemiotes sonselaensis gen. et sp. nov., from a partial left dentary recovered from the Sonsela Member of the Chinle Formation (middle Norian, Upper Triassic) of northeastern Arizona, U.S.A. The three dentary teeth have apices that are distally reclined relative to their bases and the tip of the posteriormost tooth curves mesially. The teeth show subthecodont implantation and are interspaced by empty sockets that terminate above the Meckelian canal, which is dorsoventrally expanded posteriorly. Replacement tooth sockets are positioned distolingually to the active teeth as in varanid-like replacement. We identify this new specimen as a diapsid reptile based on its monocuspid teeth that lack carinae and serrations. A more exclusive phylogenetic position within Diapsida is not well supported and remains uncertain. Several features of this new taxon, such as the presence of an intramandibular septum, are shared with some anguimorph squamates; however, these likely evolved independently. The teeth of the new taxon are distinctively marked by external grooves that occur on the entire length of the crown on the labial and lingual sides, as seen in the teeth of living beaded lizards. If these grooves are functionally similar to those of beaded lizards, which use the grooves to deliver venom, this new taxon represents the oldest known reptile where venom-conducting teeth are preserved within a jaw. The teeth of the new species are anatomically distinct from and ~10x smaller than those of the only other known Late Triassic hypothesized venomous reptile, Uatchitodon, supporting venom use across multiple groups of different body size classes. This new species represents the third Late Triassic reptile species to possibly have used envenomation as a feeding (and/or defensive) strategy, adding to the small number of venomous reptiles known from the Mesozoic Era.