Mark W Westneat

Mark W Westneat
University of Chicago | UC · Department of Organismal Biology & Anatomy

PhD

About

215
Publications
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Introduction
My research interests are molecular phylogenetics (generating the tree of life), and biomechanics (how animals work). I mostly work on fishes, doing field work on coral reefs, watching feeding behavior in the lab and field, looking at evolution through the tree of life, and developing computer models of skull function.

Publications

Publications (215)
Article
Full-text available
Body size is an important species trait, correlating with life span, fecundity, and other ecological factors. Over Earth’s geological history, climate shifts have occurred, potentially shaping body size evolution in many clades. General rules attempting to summarize body size evolution include Bergmann’s rule, which states that species reach larger...
Article
Research on the water-to-land transition tends to focus on the locomotor changes necessary for terrestriality. But the evolution from water breathing to air breathing was also a necessary precursor to the invasion of land. Air is approximately 1,000 times less dense, 50 times less viscous, and contains hundreds of times more oxygen than water. Howe...
Preprint
Suction feeding in fishes is characterized by rapid movement of cranial elements, but extant lungfishes (Sarcopterygii: Dipnoi) exhibit a reduced number and mobility of cranial bones relative to actinopterygian fishes. Despite fusion of cranial elements, lungfishes are proficient at suction feeding, though the impacts of novel cranial morphology an...
Preprint
Full-text available
Clades of marine fishes exhibit many patterns of diversification, ranging from relatively constant throughout time to rapid changes in the rates of speciation and extinction. The goatfishes (Syngnatharia: Mullidae) are a family of marine, reef associated fishes with a relatively recent origin, distributed globally in tropical and temperate waters....
Article
Many fishes use substantial cranial kinesis to rapidly increase buccal cavity volume, pulling prey into the mouth via suction feeding. Living polypterids are a key lineage for understanding the evolution and biomechanics of suction feeding due to their phylogenetic position and unique morphology. Polypterus bichir have fewer mobile cranial elements...
Article
Full-text available
The damselfishes (family Pomacentridae) inhabit near-shore communities in tropical and temperature oceans as one of the major lineages in coral reef fish assemblages. Our understanding of their evolutionary ecology, morphology and function has often been advanced by increasingly detailed and accurate molecular phylogenies. Here we present the next...
Preprint
Triggerfishes and filefishes exhibit a wide range of fin and body morphologies, inhabit many marine habitats, and feed on a variety of benthic and pelagic organisms. Particular morphologies are predicted to provide functional advantages for swimming behaviors that facilitate life in diverse habitats and feeding guilds. Ecomorphological relationship...
Article
Full-text available
Synopsis Wing shape plays a critical role in flight function in birds and other powered fliers and has been shown to be correlated with flight performance, migratory distance, and the biomechanics of generating lift during flight. Avian wing shape and flight mechanics have also been shown to be associated with general foraging behavior and habitat...
Preprint
Full-text available
The damselfishes (family Pomacentridae) inhabit near-shore communities in tropical and temperature oceans as one of the major lineages with ecological and economic importance for coral reef fish assemblages. Our understanding of their evolutionary ecology, morphology and function has often been advanced by increasingly detailed and accurate molecul...
Article
Full-text available
Vertebrate dentitions are often collapsed into a few discrete categories, obscuring both potentially important functional differences between them and insight into their evolution. The terms homodonty and heterodonty typically conflate tooth morphology with tooth function, and require context-dependent subcategories to take on any specific meaning....
Article
For many species of fishes, rhythmic movement of the pectoral fins, or forelimbs, drives locomotion. In terrestrial vertebrates, normal limb-based rhythmic gaits require ongoing modulation with limb mechanosensors. Given the complexity of the fluid environment and dexterity of fish swimming through it, we hypothesize that mechanosensory modulation...
Data
Video S1. In situ manipulation demonstrating the interconnectedness of the Atractosteus spatula cranial linkage mechanism. A steel wire looped around the anterior tip of the cleithrum and dorsal to the sternohyoideus is used to simulate input of the sternohyoideus and hypaxial muscles in the feeding system of A. spatula. Initially, at resting state...
Data
Video S2. Animation of the Atractosteus spatula feeding mechanism showing anterior-to-posterior expansion of cranial elements throughout the feeding cycle. Initially, the buccal cavity expands as the jaws open and the hyoid remains elevated. This is followed by pharyngeal expansion as the hyoid depresses with the jaws remaining open. Finally, operc...
Data
This document contains supplementary information for - Feeding kinematics and morphology of the alligator gar (Atractosteus spatula , Lacépède, 1803). This PDF file includes: Figures S1 to S12
Article
Full-text available
Living gars are a small clade of seven species that occupy an important position on the actinopterygian phylogenetic tree as members of Holostei, sister‐group to teleosts, and exhibit many plesiomorphic traits used to interpret and reconstruct early osteichthyan feeding mechanisms. Previous studies of gar feeding kinematics have focused on the ram‐...
Article
Full-text available
Coral reefs are complex marine habitats that have been hypothesized to facilitate functional specialization and increased rates of functional and morphological evolution. Wrasses (Labridae: Percomorpha) in particular, have diversified extensively in these coral reef environments and have evolved adaptations to further exploit reef-specific resource...
Chapter
Full-text available
The evolutionary history of feeding biomechanics in fishes is a spectacular story of change in the structure and function of highly kinetic vertebrate skulls. From ratfishes to wrasses there is a spectacular diversity of skull form and feeding mechanisms among fishes, from sit-and-wait predators that use high suction forces to engulf their prey, to...
Article
Full-text available
Triggerfishes and filefishes (Balistoidea) use balistiform locomotion to power steady swimming with their dorsal and anal fins, and transition to a gait dominated by body and caudal fin (BCF) kinematics at high speeds. Fin and body shapes are predicted to be strong determinants of swimming performance and gait transitions. The goal of this study wa...
Preprint
Modern (lepisosteid) gars are a small clade of seven species and two genera that occupy an important position on the actinopterygian phylogenetic tree as members of the Holostei ( Amia + gars), sister-group of the teleost radiation. Often referred to as “living fossils,” these taxa preserve many plesiomorphic characteristics used to interpret and r...
Article
Full-text available
Biological color may be adaptive or incidental, seasonal or permanent, species-or population-specific, or modified for breeding, defense or camouflage. Although color is a hugely informative aspect of biology, quantitative color comparisons are notoriously difficult. Color comparison is limited by categorization methods, with available tools requir...
Preprint
Triggerfishes and filefishes (Balistoidea) use balistiform locomotion to power slow steady swimming with their dorsal and anal fins and transition to a gait dominated by body and caudal fin (BCF) kinematics at high speeds. Fin and body shapes are predicted to be strong determinants of swimming performance and the biomechanics of gait transitions. T...
Preprint
Full-text available
Biological color may be adaptive or incidental, seasonal or permanent, species- or population-specific, or modified for breeding, defense or camouflage. Although color is a hugely informative aspect of biology, quantitative color comparisons are notoriously difficult. Color comparison is limited by categorization methods, with available tools requi...
Preprint
Biological color may be adaptive or incidental, seasonal or permanent, species- or population-specific, or modified for breeding, defense or camouflage. Although color is a hugely informative aspect of biology, quantitative color comparisons are notoriously difficult. Color comparison is limited by categorization methods, with available tools requi...
Article
Full-text available
Vertical transmission of Symbiodinium symbionts between generations of coral hosts has been hypothesized to result in superior matches between host and symbiont physiologies, and to form holobionts that are generally more resistant to thermal stress. Alternatively, horizontal transmission, with its greater potential for assembling physiologically d...
Article
Full-text available
Mechanosensation is a universal feature of animals that is essential for behavior, allowing detection of animals' own body movement and position as well as physical features of the environment. Fish fins provide a key vertebrate system for studying mechanosensation. The extraordinary morphological and behavioral diversity that exists across fish sp...
Article
The organization of tissues in appendages often affects their mechanical properties and function. In the fish family Labridae, swimming behavior is associated with pectoral fin flexural stiffness and morphology, where fins range on a continuum from stiff to relatively flexible fins. Across this diversity, pectoral fin flexural stiffness decreases e...
Preprint
Full-text available
Color is a central aspect of biology, with important impacts on ecology and evolution. Organismal color may be adaptive or incidental, seasonal or permanent, species- or population-specific, or modified for breeding, defense or camouflage. Thus, measuring and comparing color among organisms provides important biological insights. However, color com...
Article
Full-text available
Inter-module physiological integration of colonial organisms can facilitate colony-wide coordinated responses to stimuli that strengthen colony fitness and stress resistance. In scleractinian corals, whose colonial integration ranges from isolated polyps to a seamless continuum of polyp structures and functions, this coordination improves re sponse...
Article
Full-text available
The functional capabilities of flexible, propulsive, appendages are directly influenced by their mechanical properties. The fins of fishes have undergone extraordinary evolutionary diversification in structure and function, which raises questions of how fin mechanics relate to swimming behavior. In the fish family Labridae, pectoral fin swimming be...
Article
Full-text available
Labrid fishes use their pectoral fins for efficient high-speed cruising behavior, as well as for precision maneuvering in complex environments, making them good models for biomimicry applications in propulsor technology for aquatic vehicles. Lift-based labriform locomotion is a form of aquatic flight used by many species and is the sole mode of tra...
Article
Phylogenetics is undergoing a revolution as large-scale molecular datasets reveal unexpected but repeatable rearrangements of clades that were previously thought to be disparate lineages. One of the most unusual clades of fishes that has been found using large-scale molecular datasets is an expanded Syngnathiformes including traditional long-snoute...
Article
Full-text available
The biomechanics of animal limbs has evolved to meet the functional demands for movement associated with different behaviors and environments. Effective movement relies not only on limb mechanics but also on appropriate mechanosensory feedback. By comparing sensory ability and mechanics within a phylogenetic framework, we show that peripheral mecha...
Article
Full-text available
Winnowing is a foraging strategy common in geophagine cichlids (Cichlidae), in which sediment is sifted for food in the oral cavity. Geophagines have modified pharyngeal structures that function in winnowing, although detailed anatomical and functional information is still needed to clarify the mechanisms by which these fishes obtain food by siftin...
Article
Full-text available
Most species-rich lineages of aquatic organisms have undergone divergence between forms that feed from the substrate (benthic feeding) and forms that feed from the water column (pelagic feeding). Changes in trophic niche are frequently accompanied by changes in skull mechanics, and multiple fish lineages have evolved highly specialized biomechanica...
Article
Full-text available
Many musculoskeletal systems, including the skulls of birds, fishes, and some lizards consist of interconnected chains of mobile skeletal elements, analogous to linkage mechanisms used in engineering. Biomechanical studies have applied linkage models to a diversity of musculoskeletal systems, with previous applications primarily focusing on two-dim...
Article
Full-text available
Background: At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable a...
Article
Full-text available
The robust skull and highly subdivided adductor mandibulae muscles of triggerfishes provide an excellent system within which to analyze the evolutionary processes underlying phenotypic diversification. We surveyed the anatomical diversity of balistid jaws using Procrustes-based geometric morphometric analyses and a phylomorphospace approach to quan...
Research
Full-text available
This lab is an exercise on fish skull anatomy developed at Duke by John Lundberg back in the 1980s and modified slightly over the years. - - NOTE! When printing, do not "scale to fit". Printed version should have the same font size for bone names across all pages- otherwise it won't fit together quite right. The first block- occipital block- is pa...
Article
The Red Sea is characterised by a unique fauna and historical periods of desiccation, hypersalinity and intermittent isolation. The origin and contemporary composition of reef-associated taxa in this region can illuminate biogeographical principles about vicariance and the establishment (or local extirpation) of existing species. Here we aim to: (1...
Article
Full-text available
Aim The geological and palaeo-climatic forces that produced the unique biodiversity in the Red Sea are a subject of vigorous debate. Here, we review evidence for and against the hypotheses that: (1) Red Sea fauna was extirpated during glacial cycles of the Pleistocene and (2) coral reef fauna found refuge within or just outside the Red Sea during l...
Article
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If you go fishing and cast your lure out across a pond, settling it skillfully by the lily pads, you may see the water drop out from under your bait with a sucking whirlpool as you engage with the most popular sport fish in the world, the largemouth bass. Almost all popular recreational sport fish species (bass, salmon, trout, pike, grouper, snappe...
Article
Full-text available
Extensive morphometric surveys of diverse clades have the power to reveal large-scale patterns of morphological and ecological diversification (Clabaut et al. 2007; Angielczyk, Feldman & Miller 2011), informing questions ranging from how modularity shapes diversification (Drake & Klingenberg 2010) to how morphology relates to ecological function (W...
Article
Full-text available
Here we present a re-description of Abudefduf luridus and reassign it to the genus Similiparma. We supplement traditional diagnoses and descriptions of this species with quantitative anatomical data collected from a family-wide geometric morphometric analysis of head morphology (44 species representing all 30 damselfish genera) and data from crania...
Preprint
Full-text available
Visual media can captivate, fascinate, and inspire. Whether skillfully taken photographs or artfully crafted visual illustrations, visuals convey beauty in ways that words can’t, and can tell even complex stories to audiences that might otherwise not listen. The story of biological evolution is highly complex and the subject of an enduring quest fo...
Preprint
Visual media can captivate, fascinate, and inspire. Whether skillfully taken photographs or artfully crafted visual illustrations, visuals convey beauty in ways that words can’t, and can tell even complex stories to audiences that might otherwise not listen. The story of biological evolution is highly complex and the subject of an enduring quest fo...
Article
Full-text available
Background Scientists rarely reuse expert knowledge of phylogeny, in spite of years of effort to assemble a great “Tree of Life” (ToL). A notable exception involves the use of Phylomatic, which provides tools to generate custom phylogenies from a large, pre-computed, expert phylogeny of plant taxa. This suggests great potential for a more generaliz...