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Gaining the ability to predict population responses to climate change is a pressing concern. Using a “natural experiment,” we show that testing for divergent evolution in wild populations from contrasting thermal environments provides a powerful approach, and likely an enhanced predictive power for responses to climate change. Specifically, we used a unique study system in Iceland, where freshwater populations of threespine sticklebacks (Gasterosteus aculeatus) are found in waters warmed by geothermal activity, adjacent to populations in ambient-temperature water. We focused on morphological traits across six pairs from warm and cold habitats. We found that fish from warm habitats tended to have a deeper mid-body, a subterminally orientated jaw, steeper craniofacial profile, and deeper caudal region relative to fish from cold habitats. Our common garden experiment showed that most of these differences were heritable. Population age did not appear to influence the magnitude or type of thermal divergence, but similar types of divergence between thermal habitats were more prevalent across allopatric than sympatric population pairs. These findings suggest that morphological divergence in response to thermal habitat, despite being relatively complex and multivariate, are predictable to a degree. Our data also suggest that the potential for migration of individuals between different thermal habitats may enhance nonparallel evolution and reduce our ability to predict responses to climate change.

To report the configuration, risk factors, fixation methods and complication rates after repair of humeral condylar fractures (HCF) in French bulldogs, and report the presence of humeral intracondylar fissures (HIF) in this population as a possible predisposing factor.Retrospective clinical cohort study.Forty-four elbows.The medical records of dogs referred between January 2012 and December 2021 were searched for French bulldogs presenting with HCF. Signalment, fracture configuration, stabilization method and complication occurrence were obtained. Postoperative radiographs were assessed for implant positioning, and computed tomography (CT) scans were assessed for the presence and size of HIF in the contralateral elbow.Lateral humeral condylar fractures represented 28/44 (63.6%) of HCF in French bulldogs. Repair with a transcondylar screw (TCS) and Kirschner-wire(s) (K-wire) were 7.62 times more likely to result in a major complication (95% CI: 1.43, 21.89; p = .01) compared to other methods. All incidences (7/7) of TCS migration were within the TCS + K-wire group. A HIF was identified in 18/31 (58.1%) dogs. Older animals were not significantly less likely to have a HIF than younger animals (p = .129).Fracture stabilization with a TCS and K-wire(s) was associated with an increased risk of major complications and migration of the TCS. A HIF was present in the contralateral elbow of over half of the French bulldogs where CT was available.A HIF may be a predisposing factor of HCF in French bulldogs. Alternative methods of stabilization to a TCS and K-wire(s) should be used to reduce complication risk.

The costs and benefits of being social vary with environmental conditions, so individuals must weigh the balance between these trade-offs in response to changes in the environment. Temperature is a salient environmental factor that may play a key role in altering the costs and benefits of sociality through its effects on food availability, predator abundance, and other ecological parameters. In ectotherms, changes in temperature also have direct effects on physiological traits linked to social behaviour, such as metabolic rate and locomotor performance. In light of climate change, it is therefore important to understand the potential effects of temperature on sociality. Here, we took the advantage of a 'natural experiment' of threespine sticklebacks from contrasting thermal environments in Iceland: geothermally warmed water bodies (warm habitats) and adjacent ambient-temperature water bodies (cold habitats) that were either linked (sympatric) or physically distinct (allopatric). We first measured the sociability of wild-caught adult fish from warm and cold habitats after acclimation to a low and a high temperature. At both acclimation temperatures, fish from the allopatric warm habitat were less social than those from the allopatric cold habitat, whereas fish from sympatric warm and cold habitats showed no differences in sociability. To determine whether differences in sociability between thermal habitats in the allopatric population were heritable, we used a common garden breeding design where individuals from the warm and the cold habitat were reared at a low or high temperature for two generations. We found that sociability was indeed heritable but also influenced by rearing temperature, suggesting that thermal conditions during early life can play an important role in influencing social behaviour in adulthood. By providing the first evidence for a causal effect of rearing temperature on social behaviour, our study provides novel insights into how a warming world may influence sociality in animal populations.

Fishing‐associated selection is one of the most important human‐induced evolutionary pressures for natural populations. However, it is unclear whether fishing leads to heritable phenotypic changes in the targeted populations, as the heritability and genetic correlations of traits potentially under selection have received little attention. In addition, phenotypic changes could arise from fishing‐associated environmental effects, such as reductions in population density. Using fish reared at baseline and reduced group density and repeatedly harvested by simulated trawling, we show that trawling can induce direct selection on fish social behaviour. As sociability has significant heritability and is also genetically correlated with activity and exploration, trawling has the potential to induce both direct selection and indirect selection on a variety of fish behaviours, potentially leading to evolution over time. However, while trawling selection was consistent between density conditions, the heritability and genetic correlations of behaviours changed according to the population density. Fishing‐associated environmental effects can thus modify the evolutionary potential of fish behaviour, revealing the need to use a more integrative approach to address the evolutionary consequences of fishing.

Shape is a complex trait which can be investigated through a variety of methods that have been developed over the past century. Currently, ecologists and evolutionary biologists employ the use of geometric morphometrics on 2D images as their standard approach. Recently, there has been increased interest in the use of 3D methods. However, while low-cost 3D methods of data collection are becoming available their potential benefits are often more implied rather than quantified. Using the mandibles from two species of African cichlids (Maylandia zebra and Tropheops “Red Cheek”), this study aimed to evaluate the use of a low-cost 3D method of shape capture versus a range of 2D data sets (termed ‘standard’, ‘even’, and ‘extended’). Our findings indicated that while both 2D and 3D methods could discriminate differences in species and sexes there was only a slight improvement using 3D when landmark datasets were held even. Further, the standard approaches to data collection that would be taken by most researchers clearly outperformed our 3D approach. Therefore, as 3D methods become more accessible researchers should consider a cost/benefit ratio in terms of the time required to obtain 3D data versus shape information gained.

Objectives The aim of this study was to report the complication of lateral radial head subluxation following proximal ulnar osteotomy (PUOO) or proximal ulnar ostectomy (PUOE) in eight dogs. Materials and Methods Case records and diagnostic imaging of dogs developing lateral radial head subluxation following PUOO (n = 7) or PUOE (n = 2) were retrospectively reviewed. Information pertaining to clinical history, signalment, presenting condition, lameness grade, diagnostic imaging and initial surgery details, postoperative complications and their management were retrieved. Outcomes were established from subsequent clinical histories or telephone interviews with referring veterinarians. Comparison was made to a single-centre cohort without lateral radial head subluxation following PUOO or PUOE. Results Eight dogs (median age: 9.5 months [range: 6 months–6 years], median weight 7.7 kg [range: 5–28 kg]) were included. Six dogs had a PUOO performed; five dogs had unilateral surgery and one had bilateral surgery. Two dogs had unilateral PUOE surgery. Median time to diagnosis of lateral radial head subluxation following surgery was 6.5 weeks (range: 2–20 weeks). Five of the eight dogs had surgical revision of lateral radial head subluxation. Resolution of lateral radial head subluxation was achieved in four dogs, with three achieving acceptable to good mobility. One dog had poor postoperative mobility. A fifth dog remained lame after revision surgery failure. Three dogs did not have revision surgery; two underwent limb amputation and one dog remained lame as revision surgery was declined. Clinical Significance Lateral radial head subluxation is a potentially severe postoperative complication following PUOO or PUOE.

Conceptual models of adaptive divergence and ecological speciation in sympatry predict differential resource use, phenotype–environment correlations, and reduced gene flow among diverging phenotypes. While these predictions have been assessed in past studies, connections among them have rarely been assessed collectively. We examined relationships among phenotypic, ecological, and genetic variation in Arctic charr (Salvelinus alpinus) from six Icelandic localities that have undergone varying degrees of divergence into sympatric benthic and pelagic morphs. We characterized morphological variation with geometric morphometrics, tested for differential resource use between morphs using stable isotopes, and inferred the amount of gene flow from single nucleotide polymorphisms. Analysis of stable isotopic signatures indicated that sympatric morphs showed similar difference in resource use across populations, likely arising from the common utilization of niche space within each population. Carbon isotopic signature was also a significant predictor of individual variation in body shape and size, suggesting that variation in benthic and pelagic resource use is associated with phenotypic variation. The estimated percentage of hybrids between sympatric morphs varied across populations (from 0% to 15.6%) but the majority of fish had genotypes (ancestry coefficients) characteristic of pure morphs. Despite evidence of reduced gene flow between sympatric morphs, we did not detect the expected negative relationship between divergence in resource use and gene flow. Three lakes showed the expected pattern, but morphs in the fourth showed no detectable hybridization and had relatively low differences in resource use between them. This coupled with the finding that resource use and genetic differentiation had differential effects on body shape variation across populations suggests that reproductive isolation maintains phenotypic divergence between benthic and pelagic morphs when the effects of resource use are relatively low. Our ability to assess relationships between phenotype, ecology, and genetics deepens our understanding of the processes underlying adaptive divergence in sympatry., Our study assesses the contribution of differential resource use, phenotype–environment correlations, and reductions in gene flow to adaptive divergence of benthic–pelagic morphs of Icelandic Arctic charr in sympatry. We integrate a variety of analytical approaches to test our hypotheses using geometric morphometrics, stable isotopic signatures, and single nucleotide polymorphisms. Resource use appears to be the agent of selection driving phenotypic divergence along a benthic–pelagic axis and reproductive isolation may maintain this divergence when the intensity of divergent selection is weak. ​

Environmental conditions can impact the development of phenotypes and in turn the performance of individuals. Climate change, therefore, provides a pressing need to extend our understanding of how temperature will influence phenotypic variation. To address this, we assessed the impact of increased temperatures on ecologically significant phenotypic traits in Arctic charr (Salvelinus alpinus). We raised Arctic charr at 5°C and 9°C to simulate a predicted climate change scenario and examined temperature-induced variation in ossification, bone metabolism, skeletal morphology, and escape response. Fish reared at 9°C exhibited less cartilage and bone development at the same developmental stage, but also higher bone metabolism in localized regions. The higher temperature treatment also resulted in significant differences in craniofacial morphology, changes in the degree of variation, and fewer vertebrae. Both temperature regime and vertebral number affected escape response performance, with higher temperature leading to decreased latency. These findings demonstrate that climate change has the potential to impact development through multiple routes with the potential for plasticity and the release of cryptic genetic variation to have strong impacts on function through ecological performance and survival.

Major advances towards our understanding of adaptive genetic variation are now readily obtainable in the post-genomic era. Cichlid biology has a continuing history of benefitting from the latest technical advances in sequencing technology. This is now allowing for the discovery of allelic variation related to key evolutionary traits such as colour, morphology, brain and behavioural variation, and sex. However, just as the ability to explore cichlid genomes has increased, it is becoming apparent that phenotypes are influenced by an array of factors, sometimes with environmental conditions determining the genetic basis of traits. This mirrors a growing awareness across biology of the range of mechanisms beyond genetic variation that can be responsible for generating phenotypic variation. Fortunately, cichlids provide a highly tractable study system that can be leveraged to account for such complexity. We outline some of the major findings in cichlid genomics over the past years and provide a framework for effective approaches that can be used to make further discoveries about complex traits within a genomic context. We then move on to some of the core topics facing the field, such as the environmental drivers of phenotypes, sex determination mechanisms, and neurobiology. The utility of a genomic understanding of these traits from cichlids is also clearly relevant within a clinical context, especially as we tackle an understanding of more complex and continuous phenotypic variation.

Human activity is drastically altering the habitat use of natural populations. This has been documented as a driver of phenotypic divergence in a number of wild animal populations. Here, we show that urban and rural populations of red foxes ( Vulpes vulpes ) from London and surrounding boroughs are divergent in skull traits. These changes are primarily found to be involved with snout length, with urban individuals tending to have shorter and wider muzzles relative to rural individuals, smaller braincases and reduced sexual dimorphism. Changes were widespread and related to muscle attachment sites and thus are likely driven by differing biomechanical demands of feeding or cognition between habitats. Through extensive sampling of the genus Vulpes , we found no support for phylogenetic effects on skull morphology, but patterns of divergence found between urban and rural habitats in V. vulpes quantitatively aligned with macroevolutionary divergence between species. The patterns of skull divergence between urban and rural habitats matched the description of morphological changes that can occur during domestication. Specifically, urban populations of foxes show variation consistent with ‘domestication syndrome’. Therefore, we suggest that occurrences of phenotypic divergence in relation to human activity, while interesting themselves, also have the potential to inform us of the conditions and mechanisms that could initiate domestication. Finally, this also suggests that patterns of domestication may be developmentally biased towards larger patterns of interspecific divergence.

Objective The aim of this study was to describe the use of patient-specific three-dimensional (3D)-printed osteotomy guides, repositioning guides and custom-printed titanium plates for acute correction of antebrachial limb deformities in four dogs. Methods Retrospective review of antebrachial limb deformities in small breed chondrodystrophic dogs that were surgically corrected using a closing wedge ostectomy of the radius at a predetermined site using patient-specific osteotomy guides. Reduction was achieved without the need for intraoperative measurements using patient-specific 3D-printed repositioning guides secured and manipulated using temporary Kirschner wire fixation. The ostectomy of the radius was stabilized with a patient-specific 3D-printed titanium plate. Results All limbs were corrected to within 3.5 degrees (standard deviation [SD]: 1 degree) and 7.5 degrees (SD: 3 degrees) of the pre-planned deformity correction in the frontal and sagittal planes, respectively. No complications were encountered. Owners completed a canine orthopaedic index survey at a median postoperative follow-up time of 19 months. Surgery eliminated the main presenting complaint of buckling over of the manus in all cases. Clinical Significance The 3D-printed osteotomy repositioning guides and titanium plates facilitated accurate acute correction of antebrachial deformities in this case series. The methodology described simplifies intraoperative surgical decision-making on limb position with good clinical outcomes seen in a small number of clinical cases.

Objectives The aim of this study is to describe the presentation, surgical management and perioperative outcome of cats with acetabular fractures. Methods Case records and radiographs of cats with acetabular fractures were reviewed from presentation to the end of follow-up. Surgical technique, complications, radiographic reduction and the presence of neurological deficits were recorded. Results Sixteen cats with 17 acetabular fractures met the inclusion criteria. All fractures were associated with concurrent orthopaedic injuries. All cats were either moderately or severely lame on presentation. Five fractures were stabilised using screws, wire, pins and polymethylmethacrylate, nine were repaired using a straight dynamic compression plate and three were repaired using a locking plate. Two of seven cats that were neurologically normal prior to surgery developed transient neuropraxia following surgery. There were three major complications and no minor complications. At the end of follow-up 3/16 cats had full function, whereas 13/16 had acceptable function. Conclusions and relevance All cats undergoing surgical stabilisation of acetabular fractures returned to full or acceptable function by the end of the follow-up period and there was a low number of intraoperative and short-term complications. Neurological deficits were common preoperatively, but the majority of these deficits had resolved by follow-up.

Objectives To evaluate the reliability of CT measurement of canine elbow axial radioulnar congruence using a duplicated circle superimposition technique. Materials and Methods CT of six cadaveric canine elbows was performed following either: (1) placement of an external fixator on the radius with ostectomy and radial shortening of 1 to 5 mm; (2) radial lengthening of 1 to 5 mm using a radial lengthening system; or, (3) no axial length adjustment. Four observers, on two occasions, blinded to the amount of radial adjustment, placed a circle of best fit of the ulnar trochlear notch on a sagittal image that was duplicated and transposed to the articular contour of the radial head; then the axial distance between circles relative to the dorsal radius was measured. Statistical analysis assessed differences between actual and observer-assessed radial length adjustment; inter−/intra-observer interclass correlation coefficients and sensitivity/specificity were calculated to evaluate measurement reliability. Results There was not a significant difference between actual and observer measures of radioulnar congruence. Inter- (intraclass correlation coefficient=0.98) and intra-observer reliability (intraclass correlation coefficient=0.94 to 0.99) were almost perfect for measurement of radioulnar incongruence when compared to the actual radial adjustment. A Bland–Altman plot revealed a 95% confidence interval range of −1.31 to 1.16 mm. Sensitivity and specificity were high for correct identification of congruent elbows and elbows with 1 or 2 mm incongruency. Clinical Significance The duplicated circle superimposition technique provides a simple and accurate means of assessing radioulnar axial incongruence.

Unprecedented rates of species extinction increase the urgency for effective conservation biology management practices. Thus, any improvements in practice are vital and we suggest that conservation can be enhanced through recent advances in evolutionary biology, specifically advances put forward by evolutionary developmental biology (i.e., evo-devo). There are strong overlapping conceptual links between conservation and evo-devo whereby both fields focus on evolutionary potential. In particular, benefits to conservation can be derived from some of the main areas of evo-devo research, namely phenotypic plasticity, modularity and integration, and mechanistic investigations of the precise developmental and genetic processes that determine phenotypes. Using examples we outline how evo-devo can expand into conservation biology, an opportunity which holds great promise for advancing both fields.

Objective To identify the most common methods used by surgeons to place finger-trap sutures (FTS), and determine their influence on the biomechanical properties of constructs. Study design Questionnaire and experimental study. Methods Six commonly used FTS methods (A-F) were identified from literature review and questionnaire. Constructs made with 3-metric nylon suture and 18-French polyurethane esophagostomy tubing were tested in axial loading to failure. Two patterns (B and D) selected based on common use and biomechanical performance were further tested, with 2, 4, and 8 repeats along the tube. Displacement, load, and energy at failure were compared between constructs, and failure mode was video recorded. Results Patterns E and F were susceptible to slipping (P

Summary Objectives: To describe the use, quality of life, compliance, complications, and outcome of animals fitted with stump socket prostheses. Methods: Medical records of dogs fitted with a stump socket prosthesis were reviewed. Functional outcome, quality of life and complications were retrospectively assessed from an owner questionnaire. Results: Thirteen stump socket prostheses (12 dogs) were fitted for a variety of reasons including trauma, congenital abnormalities, and neoplasia. Eight dogs had a good outcome overall and four a poor outcome. Quality of life (QOL) remained good or excellent in 10/12 dogs. Nine complications were seen in 7/12 dogs, most were manageable; surgical wound complications (n = 2) and pressures sores (n = 4) were the most frequently encountered. One dog suffered multiple complications. Thoracic and pelvic limb stump socket prostheses had a similar complication rate, however all animals with a poor outcome had a thoracic limb stump socket prosthesis; two were small breed dogs (under 10 kg) and two had bilateral thoracic limb abnormalities. Clinical significance: Stump socket prostheses are feasible and versatile in animals. In correctly selected cases, good to excellent outcomes are possible. However, complications are frequent but often manageable. Further investigations are required into the risk factors for poor outcomes and prospective studies are required to assess changes in biomechanics, function, and QOL before and after fitting of a stump socket prosthesis. Until further evidence is available, careful consideration should be given before fitting bilateral thoracic limb stump socket prostheses or thoracic limb stump socket prostheses to small breed dogs.Supplementary Material to this article is available online at https://doi.org/10.3415/VCOT-16-09-0127

In light of global climate change, there is a pressing need to understand and predict the capacity of populations to respond to rising temperatures. Metabolic rate is a key trait that is likely to influence the ability to cope with climate change. Yet, empirical and theoretical work on metabolic rate responses to temperature changes has so far produced mixed results and conflicting predictions.Our study addresses this issue using a novel approach of comparing fish populations in geothermally warmed lakes and adjacent ambient‐temperature lakes in Iceland. This unique ‘natural experiment’ provides repeated and independent examples of populations experiencing contrasting thermal environments for many generations over a small geographic scale, thereby avoiding the confounding factors associated with latitudinal or elevational comparisons. Using Icelandic sticklebacks from three warm and three cold habitats, we measured individual metabolic rates across a range of acclimation temperatures to obtain reaction norms for each population.We found a general pattern for a lower standard metabolic rate (SMR) in sticklebacks from warm habitats when measured at a common temperature, as predicted by Krogh's rule. Metabolic rate differences between warm‐ and cold‐habitat sticklebacks were more pronounced at more extreme acclimation temperatures, suggesting the release of cryptic genetic variation upon exposure to novel conditions, which can reveal hidden evolutionary potential. We also found a stronger divergence in metabolic rate between thermal habitats in allopatry than sympatry, indicating that gene flow may constrain physiological adaptation when dispersal between warm and cold habitats is possible.In sum, our study suggests that fish may diverge toward a lower SMR in a warming world, but this might depend on connectivity and gene flow between different thermal habitats. A free Plain Language Summary can be found within the Supporting Information of this article., A free Plain Language Summary can be found within the Supporting Information of this article.

The generation of variation is paramount for the action of natural selection. Although biologists are now moving beyond the idea that random mutation provides the sole source of variation for adaptive evolution, we still assume that variation occurs randomly. In this review, we discuss an alternative view for how phenotypic plasticity, which has become well accepted as a source of phenotypic variation within evolutionary biology, can generate nonrandom variation. Although phenotypic plasticity is often defined as a property of a genotype, we argue that it needs to be considered more explicitly as a property of developmental systems involving more than the genotype. We provide examples of where plasticity could be initiating developmental bias, either through direct active responses to similar stimuli across populations or as the result of programmed variation within developmental systems. Such biased variation can echo past adaptations that reflect the evolutionary history of a lineage but can also serve to initiate evolution when environments change. Such adaptive programs can remain latent for millions of years and allow development to harbor an array of complex adaptations that can initiate new bouts of evolution. Specifically, we address how ideas such as the flexible stem hypothesis and cryptic genetic variation overlap, how modularity among traits can direct the outcomes of plasticity, and how the structure of developmental signaling pathways is limited to a few outcomes. We highlight key questions throughout and conclude by providing suggestions for future research that can address how plasticity initiates and harbors developmental bias.

Objectives To describe reduction techniques and clinical outcome in a series of traumatic elbow luxations in cats. Materials and methods Retrospective review of unilateral elbow luxations treated at five specialist referral centres. Data included signalment, aetiology, concurrent injuries, luxation direction, time to reduction, primary reduction technique, surgical procedure and complications. Cases were excluded if reduction technique was unknown. Telephone owner questionnaire follow-up was completed using a Feline Musculoskeletal Pain Index. Results Thirty-two cats were included. Lateral luxations were most common (n = 21). Time (hours) until attempted initial closed reduction was 48 (n = 3) or unrecorded (n = 4). Luxation was treated by closed reduction alone (n = 7) or by surgery (n = 25); 14 of 25 cases underwent primary surgical reduction and 11 of 25 were secondary procedures following failure of closed reduction. Transcondylar bone tunnels and circumferential suture (n = 19) was the most commonly used surgical technique. Catastrophic (n = 1), major (n = 11) and minor complications (n = 5) were recorded; reluxation occurred more frequently after closed reduction (n = 8) than after open reduction with fixation (n = 0). Feline Musculoskeletal Pain Index data were available for 12 cats; outcome was good-excellent in all 12, with a median function score of 64.5/68 (range: 55-68) and a median pain score of 0/15 (range: 0-5). Outcome was not associated with reduction technique. Clinical significance Elbow reluxation occurred in 61% of cats following primary closed reduction but did not occur in any open reduction cases. Reluxation rate increased with duration from injury. Most cats had good-excellent owner-assessed outcome, regardless of reduction technique.

Given the threat of climate change to biodiversity, a growing number of studies are investigating the potential for organisms to adapt to rising temperatures through changes in their physiology, morphology, and behaviour. Earlier work has predicted that evolutionary adaptation to climate change will be accompanied by a shift in temperature preferences, but empirical evidence for this is limited. Here, we test whether exposure to a warm environment over multiple generations has led to the evolution of higher preferred temperatures in the wild. We have taken advantage of a ‘natural experiment’ in Iceland, where freshwater populations of threespine sticklebacks (Gasterosteus aculeatus) are found in waters warmed by geothermal activity year-round (warm habitats), adjacent to populations in ambient-temperature lakes (cold habitats). We hypothesised that sticklebacks from warm habitats would prefer higher water temperatures than those from cold habitats, but we found no support for this hypothesis. Fish from both warm and cold habitats had an average preferred temperature of 13°C, which is considerably lower than the temperatures experienced by fish in warm habitats for most of the year. Our results therefore challenge the assumption that temperature preferences in ectotherms will readily evolve as a response to climate change. Furthermore, the fact that warm-habitat fish are able to persist at relatively high temperatures despite a lower temperature preference suggests that preferred temperature may be a poor indicator of a population’s evolutionary potential and capacity to adapt to a novel thermal environment.

In light of climate change, the ability to predict evolutionary responses to temperature changes is of central importance for conservation efforts. Prior work has focused on exposing model organisms to different temperatures for just one or a few generations under laboratory conditions. Using a ‘natural experiment’, we show that studying parallel evolution in wild populations from contrasting thermal environments presents a more powerful approach for understanding and predicting responses to climate change. More specifically, we used a unique study system in Iceland, where freshwater populations of threespine sticklebacks (Gasterosteus aculeatus) are found in waters warmed by geothermal activity, adjacent to populations in ambient-temperature water. We used three sympatric and three allopatric warm-cold population pairs to test for repeated patterns of morphological divergence in relation to thermal habitat. We found that thermal habitat explained over 50% of body shape variation: fish from warm habitats had a deeper mid-body, a shorter jaw, and smaller eyes. Our common garden experiment showed that most of these morphological differences between thermal habitats were heritable. Lastly, absence of gene flow seems to facilitate parallel divergence across thermal habitats: all three allopatric population pairs were on a common evolutionary trajectory, whereas sympatric pairs followed different trajectories. Our findings therefore suggest that morphological responses to rising temperatures can be predictable when there is limited gene flow. On the other hand, migration of individuals between different thermal habitats or microhabitats can exaggerate nonparallel evolution and reduce our ability to predict evolutionary responses.

Background: Our understanding of the biology of osteoblasts is important as they underpin bone remodelling, fracture healing and processes such as osseointegration. Osteoblasts isolated from human humeral samples display distinctive biological activity in vitro, which relates to the samples' bone types (subchondral (S), trabecular (T), cortical (C)). Our aim was to isolate primary osteoblast cultures from different bone types from the proximal femur of a clinical population of dogs presented for total hip replacement and compare the behaviour of the osteoblasts derived from different bone types, to identify a preferred bone type for isolation. Results: No differences were found for osteoblast doubling time (median for S = 2.9, T = 3.1 and C = 2.71 days, respectively; p = 0.33), final cell number (median for S = 54,849, T = 49,733, C = 61,390 cells/cm 2 ; p = 0.34) or basal tissue non-specific alkaline phosphatase (TNAP) activity (median for S = 0.02, T = 0.02, C = 0.03 U/min/mg protein; p = 0.81) between bone types after 6 days of culture in basal media. There were no differences in mineralizing TNAP activity (S = 0.02, T = 0.02, C = 0.03 U/min/mg protein, p = 0.84) or in mineralized area (S = 0.05, T = 0.04, C = 0.04%, p = 0.92) among cells from different bone types. Conclusions: There is no significant difference in mean doubling time, basal or mineralizing TNAP activity or mineralized area in osteoblasts derived from subchondral, cortical, or trabecular bone types from the canine femoral head. However, there appears to be a high level of inter-animal variability in the studied parameters, which was independent of age, body mass, and sex. Trabecular isolate osteoblasts have the least variation of the bone types studied, and therefore should be considered a preferred source for primary osteoblast cultures. The work here provides baselines for canine osteoblast function, which has utility for future comparative studies.

Humans can affect the rate and trajectory of the evolution of organisms through selective harvest. Due to non-random targeting of individuals and high rates of mortality, commercial fishing can produce particularly strong selective pressures. Although numerous studies have documented the evolutionary impacts of fishing, little is known about the combined effects of environmental change and fishing-associated selection on physiological and behavioural traits. Here, using zebrafish(Danio rerio) as a model organism in a scaled-down trawl fishery, we show that capture rate increases by ∼7-fold under hypoxic conditions (35%airsaturation) as compared to fishing in normoxia. Additionally, the repeat ability of both capture vulnerability and swimming performance decreases considerably, suggesting that oxygen availability can affect selection on particular traits. The increase in capture vulnerability is accompanied by a decrease in swimming performance(as indicated by critical swimming speed) during exposure to hypoxia, suggesting a functional link between these two integrative phenotypic traits. We observed no strong relationship between capture vulnerability and metabolic variables (standard metabolic rate and maximum metabolic rate).Our findings highlight that prevailing environmental conditions can influence harvest-associated selectivity by influencing trait repeatability and altering among individual trait variation. These effects suggest a disrupted capacity for trait-based selection in an increasingly hypoxic aquatic environment.

A major goal of evolutionary science is to understand how biological diversity is generated and altered. Despite considerable advances, we still have limited insight into how phenotypic variation arises and is sorted by natural selection. Here we argue that an integrated view, which merges ecology, evolution and developmental biology (eco evo devo) on an equal footing, is needed to understand the multifaceted role of the environment in simultaneously determining the development of the phenotype and the nature of the selective environment, and how organisms in turn affect the environment through eco evo and eco devo feedbacks. To illustrate the usefulness of an integrated eco evo devo perspective, we connect it with the theory of resource polymorphism (i.e. the phenotypic and genetic diversification that occurs in response to variation in available resources). In so doing, we highlight fishes from recently glaciated freshwater systems as exceptionally well‐suited model systems for testing predictions of an eco evo devo framework in studies of diversification. Studies on these fishes show that intraspecific diversity can evolve rapidly, and that this process is jointly facilitated by (i) the availability of diverse environments promoting divergent natural selection; (ii) dynamic developmental processes sensitive to environmental and genetic signals; and (iii) eco evo and eco devo feedbacks influencing the selective and developmental environments of the phenotype. We highlight empirical examples and present a conceptual model for the generation of resource polymorphism – emphasizing eco evo devo, and identify current gaps in knowledge., Biological Reviews, 94 (5), ISSN:1469-185X, ISSN:1464-7931, ISSN:0006-3231

Many animal taxa live in groups to increase foraging and reproductive success and aid in predator avoidance. For fish, a large proportion of species spend all or part of their lives in groups, with group coordination playing an important role in the emergent benefits of group-living. Group cohesion can be altered by an array of factors, including exposure to toxic environmental contaminants. Oil spills are one of the most serious forms of pollution in aquatic systems, and while a range of effects of acute oil exposure on animal physiology have been demonstrated, sub-lethal effects on animal behavior are relatively under-studied. Here we used an open-field behavioral assay to explore influence of acute oil exposure on social behavior in a gregarious fish native to the Gulf of Mexico, Atlantic croaker (Micropogonias undulatus). We used two oil concentrations (0.7% and 2% oil dilution, or 6.0 ± 0.9 and 32.9 ± 5.9 μg l−1 ΣPAH50 respectively) and assays were performed when all members of a group were exposed, when only one member was exposed, and when no individuals were exposed. Shoal cohesion, as assessed via mean neighbor distance, showed significant impairment following acute exposure to 2% oil. Fish in oil-exposed groups also showed reduced voluntary movement speed. Importantly, overall group cohesion was disrupted when even one fish within a shoal was exposed to 2% oil, and the behavior of unexposed in mixed groups, in terms of movement speed and proximity to the arena wall, was affected by the presence of these exposed fish. These results demonstrate that oil exposure can have adverse effects on fish behavior that may lead to reduced ecological success.

Objective To compare the mode of failure, load at yield, ultimate load to failure and stiffness of non-barbed polydioxanone, non-barbed polyglyconate and barbed glycolide-trimethylene carbonate (GTC) suture in canine cadaveric fascia. Study Design Ex vivo biomechanical study. Sample Population 18 fascia lata specimens from 9 canine cadavers. Methods 6 fascia lata specimens were sutured with polydioxanone, 6 with polyglyconate, and 6 with barbed GTC suture. Load at yield, stiffness, ultimate load to failure were measured using tensile strength testing. Statistical analysis was used to compare outcomes between suture materials. The mode of failure was recorded and described. Results The load at yield and ultimate load to failure were significantly greater for polydioxanone than barbed GTC (P=.045 and P=.016, respectively). The load at yield and ultimate load to failure was not significantly different between polydioxanone and polyglyconate (P=.687 and P=.586, respectively). The load at yield and the ultimate load to failure was not significantly different between polyglyconate and barbed GTC (P=.194 and P=.109, respectively). Stiffness was not different between constructs (P=.103). Polydioxanone and polyglyconate failed by suture breakage and suture pullout. Barbed GTC failed by suture slippage and suture breakage. Conclusion Our results showed that under the conditions of this study, 4-0 monofilament polydioxanone had a greater load at yield and load to failure than similarly sized, barbed copolymer suture in the fascia lata. This finding may help direct suture choice for fascial closure.

OBJECTIVE To report the long-term radiographic and clinical outcome of the BioMedtrix TATE elbow arthroplasty system in dogs. Assessment was via radiographs, a surgeon-based questionnaire, and owner assessment of outcome using the Liverpool osteoarthritis in dogs (LOAD) and canine brief pain inventory (CBPI) questionnaires. STUDY DESIGN Retrospective multicenter, case series. ANIMALS Client-owned dogs undergoing TATE elbow arthroplasty. METHODS Questionnaires were distributed to surgeons in the United Kingdom performing TATE elbow arthroplasty and to the owners of the dogs operated on. Owners completed the LOAD and CBPI questionnaires. All completed questionnaires from surgeons and owners, and radiographs of the dogs were collated and analyzed. RESULTS Surgeon questionnaires and radiographs were obtained for 33 elbows from 32 dogs, with owner questionnaires obtained for 19 dogs. Perioperative, short-term, and mid-term complication rates were 60%, 15%, and 15%, respectively. Radiographic assessment of component alignment showed 62% of cartridges were valgus or varus malaligned and 56% of cartridges were either translated medially or laterally relative to the long axis of the ulnar. There was no significant association between component alignment and final clinical outcome. Surgeon assessment reported 24% of dogs to have full, 52% acceptable, and 24% unacceptable outcome. Owner assessment showed significant decreases in pain severity and pain interference from preoperative to final status but no change in mobility scores. CONCLUSIONS A high complication rate and variability in component placement was recorded with TATE athroplasty. However, component malalignment did not negatively impact clinical outcome. Final clinical outcome was favorable for most cases with significant reductions in pain severity and interference scores despite no changes in mobility scores.

Objective To verify the ability of a novel Canine Elbow Realignment Osteotomy (CERO) system for acute axial radial or ulnar lengthening to restore normal elbow congruency in a shortened radius cadaver model using assessment by computed tomography (CT). Study Design In vitro cadaver study. Animals Five pairs of greyhound forelimbs from animals euthanatized for reasons unrelated to the study. Methods CT of each elbow was performed (1) pre-operatively (pre-op), (2) after placement of a linear motor IMEX™ external skeletal fixator (ESF) on the radius with diaphyseal ostectomy and radial shorting of 1–5 mm (post-ESF), and (3) after CERO surgery to lengthen the radius proximal to the ostectomy site by an amount equal to the degree of radial shortening (post-CERO). The joint space at 7 loci on dorsal plane and 6 loci on sagittal plane reconstructions was measured to assess changes in joint congruity between pre-op, post-ESF, and post-CERO. Repeated measures ANOVA with post hoc comparisons were performed to compare measurements between the 3 groups. Results Mean joint space measurements at most loci in the dorsal and sagittal planes were significantly different post-ESF compared with pre-op, confirming development of joint incongruency with the model. Post-CERO joint space measurements did not differ significantly compared with pre-op measurements, demonstrating the return to normal joint congruency using the CERO procedure. Conclusion CERO surgery restored humeroradioulnar congruency in our cadaver model and may have application for acute correction of axial radial or ulnar incongruency in canine elbows secondary to elbow dysplasia or premature growth plate closure.

Objective: To report perspectives of minimally invasive osteosynthesis (MIO) techniques in veterinary surgical practice in 2018. Study design: Electronic questionnaires. Sample population: Diplomates and residents of the American College of Veterinary Surgery and European College of Veterinary Surgery and members of the Veterinary Orthopedic Society. Methods: Survey questions pertaining to MIO and minimally invasive plate osteosynthesis (MIPO) were sent electronically to the sample population. Questions assessed training, current caseload, benefits, and limitations of MIO and MIPO. Results: Two hundred fifty-six veterinary surgeons completed questions pertaining to MIO, and 238 veterinary surgeons completed questions pertaining to MIPO. With regard to MIO, only 16% of respondents reported that they performed MIO regularly or exclusively, and 62% wanted to perform more MIO than they were currently undertaking. Tibial fractures were most commonly selected for MIO/MIPO stabilization techniques in both cats and dogs. Challenges in achieving adequate fracture reduction were identified as the greatest limitations of MIO/MIPO techniques. Forty-three percent of respondents felt there were not enough MIPO training opportunities. Conclusion: Currently, MIO/MIPO techniques are performed infrequently, with a large proportion of respondents revealing that they would like to perform more in the future. There is also evidence that additional training opportunities would be welcomed for MIPO. Clinical significance: The results of our survey provide evidence that, despite the benefits of MIO and MIPO compared with more traditional fracture stabilization approaches, significant barriers must be overcome before the techniques are likely to be more widely adopted.

Group living is widespread among animals and has a range of positive effects on individual foraging and predator avoidance. For fishes, capture by humans constitutes a major source of mortality, and the ecological effects of group living could carry‐over to harvest scenarios if fish are more likely to interact with fishing gears when in social groups. Furthermore, individual metabolic rate can affect both foraging requirements and social behaviors, and could, therefore, have an additional influence on which fish are most vulnerable to capture by fishing. Here, we studied whether social environment (i.e., social group size) and metabolic rate exert independent or interactive effects on the vulnerability of wild zebrafish (Danio rerio) to capture by a baited passive trap gear. Using video analysis, we observed the tendency for individual fish to enter a deployed trap when in different shoal sizes. Fish in larger groups were more vulnerable to capture than fish tested individually or at smaller group sizes. Specifically, focal fish in larger groups entered traps sooner, spent more total time within the trap, and were more likely to re‐enter the trap after an escape. Contrary to expectations, there was evidence that fish with a higher SMR took longer to enter traps, possibly due to a reduced tendency to follow groupmates or attraction to conspecifics already within the trap. Overall, however, social influences appeared to largely overwhelm any link between vulnerability and metabolic rate. The results suggest that group behavior, which in a natural predation setting is beneficial for avoiding predators, could be maladaptive under a trap harvest scenario and be an important mediator of which traits are under harvest associated selection.

To evaluate inter- and intraobserver reliability of the assessment of computed tomography features commonly used in the identification and classification of medial coronoid process disease and to assess inter- and intraobserver variability in the identification of the percentage ulna sclerosis from single transverse computed tomography images.Eight observers, on two occasions, reviewed 84 standardised single transverse computed tomography images acquired at the level of the apex of the medial coronoid process. Observers assessed: medial coronoid process disease, coronoid process fragmentation, osteophytes, sclerosis grade and sclerosis delineation with normal bone defined using a sclerometer. Cohen's kappa and intraclass correlation coefficient were calculated.Inter-observer agreement was fair to moderate for identification of computed tomography changes consistent with medial coronoid process disease, moderate to almost perfect for fragmentation, and moderate for osteophyte detection. Agreement was poor for sclerosis grading. Percentage sclerosis measured with a sclerometer had moderate to almost perfect inter- and intraobserver agreement.These findings suggest that subjective assessment of computed tomography images is less repeatable than more quantitative methods.

Exemplary systems for adaptive divergence are often characterized by their large degrees of phenotypic variation. This variation represents the outcome of generations of diversifying selection. However, adaptive radiations can also contain a hierarchy of differentiation nested within them where species display only subtle phenotypic differences that still have substantial effects on ecology, function, and ultimately fitness. Sexual dimorphisms are also common in species displaying adaptive divergence and can be the result of differential selection between sexes that produce ecological differences between sexes. Understanding the genetic basis of subtle variation (between certain species or sexes) is therefore important for understanding the process of adaptive divergence. Using cichlids from the dramatic adaptive radiation of Lake Malawi, we focus on understanding the genetic basis of two aspects of relatively subtle phenotypic variation. This included a morphometric comparison of the patterns of craniofacial divergence between two ecologically similar species in relation to the larger adaptive radiation of Malawi, and male–female morphological divergence between their F2 hybrids. We then genetically map craniofacial traits within the context of sex and locate several regions of the genome that contribute to variation in craniofacial shape that is relevant to sexual dimorphism within species and subtle divergence between closely related species, and possibly to craniofacial divergence in the Malawi radiation as a whole. To enhance our search for candidate genes we take advantage of population genomic data and a genetic map that is anchored to the cichlid genome to determine which genes within our QTL regions are associated with SNPs that are alternatively fixed between species. This study provides a holistic understanding of the genetic underpinnings of adaptive divergence in craniofacial shape.

Objective To measure the tensile force required for failure of the quadriceps mechanism with different tibial tuberosity widths and different degrees of rotation of the tibial plateau after radial osteotomy of the proximal tibia. Study Design Ex vivo study, randomized unblocked design Animals Thirty-five hind limbs from 18 adult Greyhound cadavers. Methods Part 1 (15 limbs)—The center of rotation of the proximal tibial radial osteotomy was advanced craniodistally, progressively reducing absolute tibial tuberosity width (ATTW) for 5 different widths. Part 2 (21 limbs)—Tibial plateau rotation was performed at a set ATTW. Rotation was varied as a function of tibial tuberosity position with rotation proximal, level with, or distal to the tuberosity. All 35 limbs were tested with force applied via the quadriceps mechanism until construct failure occurred. Results All but 2 limbs failed by fracture of the tibial tuberosity. The tensile force required for failure of the quadriceps mechanism increased linearly with increasing ATTW. Significantly less force (P = .016) was required for failure of the quadriceps mechanism when the rotation of the tibial plateau was distal to the level of the patella tendon (mean 1,877 N) compared to when it was above the level of the patella tendon (mean 2,533 N). Rotation of the tibial plateau distal to the level of the patella tendon insertion point resulted in fracture at the base of the tibial tuberosity, level with the tibial plateau buttress. Conclusion The overwhelming mode of failure of the quadriceps mechanism was by tibial tuberosity fracture, thus this was the weakest part of the construct. Reducing the tibial tuberosity width and rotation of the tibial plateau segment below the patella tendon insertion decreased the force required for tibial tuberosity fracture. These results support the idea of a safe point with the tibial plateau segment providing buttress to the tibial tuberosity.

Vertebrate evolutionary radiations are the result of divergence along a variety of ecological and behavioural axes. In addition, the potential for clades to evolve along any one axis can be strongly influenced by the types and levels of phenotypic variation that are exposed to natural selection. Understanding the factors that promote and constrain morphological diversification is a central goal of evolutionary biology. Here we use the sunfishes (Centrarchidae), a perciform family containing three main clades (Lepomis, Micropterus, and a basal clade), to explore this question with respect to variation in body shape. We gathered morphological data from 26 of the 38 centrarchid species using geometric morphometrics and analyzed the resultant shape data over a time-calibrated phylogenetic tree. We find that centrarchids partitioned body shape early in their evolutionary history, a pattern that is largely associated with expansion into divergent foraging niches and elaboration of sexual ornamentation. The morphological disparity of each clade was tightly linked to integration: those clades with high disparity (Lepomis, basal clade) were the least integrated, while the opposite trend was observed in Micropterus. We also find evidence for an increase in speciation rate at the node leading to Lepomis and Micropterus, and a decline in speciation for the basal clade. Our data lead us to suggest different hypotheses for explaining accelerated speciation in Micropterus and Lepomis: invasion of a novel pursuit-predator niche that reduced resource competition (Micropterus), and the elaboration of opercular morphology (Lepomis), a trait that is linked to reproductive behaviour and facilitates mate recognition in communities with many sunfish species.

ObjectiveTo report diaphyseal fractures of the proximal tibia following tibial tuberosity advancement without plate stabilisation for the management of cranial cruciate ligament rupture in dogs.MethodsMembers of the British Veterinary Orthopaedic Association's online discussion forum were invited to submit revision cases of tibial diaphyseal fracture following tibial tuberosity advancement without plate fixation. Data collected included signalment, surgical revision technique, pre- and postoperative revision radiographic findings, complications and veterinary assessment. Owners were invited to complete the Liverpool Osteoarthritis in Dogs questionnaire.ResultsA total of 17 dogs were included in the study. Eleven dogs had OrthoFoam-wedge modified Maquet procedures and six had the tibial tuberosity advancement rapid procedure. Tibial tuberosity advancement was maintained in 14/17 cases. Postrevision surgery complications occurred in eight cases: minor complications in 3/17 dogs; major in 5/17 and no catastrophic complications. Surgical site infection was the most common complication (4/8). Final clinical outcome found 8/17 of dogs to have excellent, 8/17 satisfactory and 1/17 poor clinical outcome. The median Liverpool Osteoarthritis in Dogs score was 12/52 (range 2 to 28). Final outcome was 6/13 owners that were very satisfied, 2/13 owners indifferent and 5/13 owners very disappointed.Clinical SignificanceThis is the first case series reporting tibial diaphyseal fractures following tibial tuberosity advancement without plate stabilisation. The authors report here a wide spectrum of potential fixation strategies should one of these fractures occur.

Objectives A survey of UK veterinarians was conducted to determine factors influencing suture choice and current suture practice for common surgical procedures. Methods An online survey was designed and the survey was sent to central practice emails obtained from the 2011 Royal College of Veterinary Surgeons (RCVS) practice database. Results Two hundred and thirty-nine surveys were completed (203 with no additional postgraduate qualifications (NAQ), 16 with RCVS certificates and 19 with diplomas). Forty-seven per cent of veterinary surgeons reported they would benefit from Continued Professional Development (CPD) pertaining to suture material selection and techniques. The NAQ group ranked practice policy, colleague influence, cost of suture material and undergraduate teaching significantly greater than diploma and certificate holders. The widest differences between suture material selection, pattern and size were identified when comparing diploma holders and the NAQ group. Diploma holders tended to choose smaller sized suture material when compared with the NAQ group. Clinical significance In conclusion, postgraduate qualifications have a significant effect on the choice, pattern and size of suture material used for many routine surgical procedures. Findings suggest that further postgraduate training pertaining to the selection and use of suture material is worthwhile and improved guidance of choice of suture material for commonly performed surgical procedures may be beneficial.

Objective To quantify, using computed tomography (CT), cross-sectional ulnar bone density (UBD), and regional radial bone density (RRBD) at the level of the medial coronoid process (MCP) in elbows with and without medial coronoid process disease (MCPD) and with and without fragmentation of MCP (FCP). Study Design Retrospective clinical case-control and ex vivo study. Sample Population Labrador Retriever elbows (n = 54) and normal cadaveric Greyhound elbows (11) undergoing elbow CT. Materials and Methods Labrador Retriever elbows were divided into 2 groups: (1) clinically unaffected and (2) MCPD-affected elbows. This 2nd group was subdivided based on the presence of a displaced FCP. UBD was measured linearly, in Hounsfield units (HU) across the widest part of the ulna incorporating the MCP. The radial head was divided into 6 zones, with mean RRBD (HU) calculated for each group. Results MCPD-affected Labrador Retriever elbows had significantly lower UBD within the MCP with a higher UBD in the cranial ulnar medulla. Lower RRBD was also seen in the radial head adjacent to the MCP in MCPD-affected Labrador Retriever elbows with FCP compared with Labrador Retriever elbows without FCP. Greyhounds had consistently lower RRBD and UBD at the apex of the MCP compared with clinically unaffected Labrador Retriever elbows. Conclusions Our results suggest a caudolateral load-transfer shift through the ulna in MCPD-affected elbow joints, unloading the MCP. Changes in regional radial head bone density suggest that the radial head is involved in the pathogenesis of MCPD.

The genetic variance that determines phenotypic variation can change across environments through developmental plasticity and in turn play a strong role in evolution. Induced changes in genotype-phenotype relationships should strongly influence adaptation by exposing different sets of heritable variation to selection under some conditions, while also hiding variation. Therefore, the heritable variation exposed or hidden from selection is likely to differ among habitats. We used ecomorphs from two divergent populations of Arctic charr (Salvelinus alpinus) to test the prediction that genotype-phenotype relationships would change in relation to environment. If present over several generations this should lead to divergence in genotype-phenotype relationships under common conditions, and to changes in the amount and type of hidden genetic variance that can evolve. We performed a common garden experiment whereby two ecomorphs from each of two Icelandic lakes were reared under conditions that mimicked benthic and limnetic prey to induce responses in craniofacial traits. Using microsatellite based genetic maps, we subsequently detected QTL related to these craniofacial traits. We found substantial changes in the number and type of QTL between diet treatments and evidence that novel diet treatments can in some cases provide a higher number of QTL. These findings suggest that selection on phenotypic variation, which is both genetically and environmentally determined, has shaped the genetic architecture of adaptive divergence in Arctic charr. However, while adaptive changes are occurring in the genome there also appears to be an accumulation of hidden genetic variation for loci not expressed in the contemporary environment.

The emergence of evo-devo has had profound effects on how we study evolution. However, evo-devo research has tended to involve two general approaches, one being mechanistic and typological with a focus on simple, bimodal phenotypes, and the other being quantitative and focusing on multidimensional phenotypes without an understanding of underlying genetic mechanisms. Here, we suggest that, given recent technological advances in genomics, molecular biology, and morphometrics, evo-devo is poised for a reconciliation through which the field will realize far greater explanatory potential with respect to the patterns and processes that underlie adaptive phenotypic divergence. With this in mind, we review the recent literature and put forward a generalized evo-devo approach that is suitable for studies of quantitative traits in a range of taxa.

Phenotypic integration is a phenomenon that manifests itself as the covariation among traits, and is thought to substantially influence how evolution unfolds, both in terms of rate and direction, which ultimately determines evolvability. To date little is known about how integration may change across an adaptive radiation, nor do we have a way of determining its genetic basis. Here we sought to test the hypotheses that (1) higher magnitudes of integration are associated with a greater degree of eco-morphological divergence, and (2) integration has a tractable genetic basis. To this end, we first evaluated the magnitude of integration at the population level in the lower jaws of two Lake Malawi cichlid species that exhibit different degrees of trophic specialization. We find that the more eco-morphologically divergent species does indeed exhibit a significantly higher magnitude of integration, which is consistent with our first hypothesis. Next, we developed a new statistical approach based on jackknife pseudovalues to produce a quantitative trait representative of inter-individual variation in the magnitude of integration. This metric was successfully applied to map the genetic basis of integration in the lower jaws of F2 hybrids derived from the two parental species that exhibited differences in the magnitude of integration. We detected three QTLs and two epistatic interactions that contribute to variation in integration within the cichlid mandible. We also detected a single QTL for lower jaw shape. None of the single QTLs for integration identified here overlapped with the interval for lower jaw shape, although one of the epistatic loci for integration did overlap with shape QTL. These results underscore a complex relationship between integration and shape, but suggest largely distinct genetic bases for these two traits. In all, our results show that phenotypic integration has a tractable, yet complex, genetic basis and that we now have the tools available to shed new light on the mechanisms that both promote and limit craniofacial diversity.

We evaluated hypotheses of intralacustrine diversification and plastic responses to two diet environments in Icelandic Arctic charr (Salvelinus alpinus). Full-sib families of progeny of wild polymorphic charr from two lakes where morphs vary in their degree of phenotypic and ecological divergence were split, with half of the offspring reared on a benthic and half on a limnetic type of diet to estimate family norms of reaction. We focused on variation in craniofacial traits because they are probably functionally related to diet and complement a previous study of body shape in these charr. A hierarchical analysis of phenotypic variation between lakes, pairs of morphs within each lake, and two families within each morph found that phenotypic variation partitioned between families relative to morphs was reduced in the more ecologically diversified population, which is consistent with adaptive diversification. The effect size of plastic responses between lake populations was similar, suggesting little difference in the degree of canalization in contrast to a previous analysis of body form plasticity. Thus, the role that plastic morphological responses play in the adaptive diversification of morphs and different lake populations of Arctic charr may depend on the trait. © 2013 The Linnean Society of London

This study reports data from a larger number of cases of triceps tendon disruption. Records from 10 veterinary referral hospitals between 2003 and 2014 were searched for canine and feline cases diagnosed with triceps tendon disruption, based on orthopaedic examination confirmed during surgery. Long-term follow-up and owner satisfaction were assessed using a questionnaire. There were 13 cases of triceps tendon disruption diagnosed across seven hospitals (nine dogs, four cats). Trauma, history or presence of a wound, surgery in the region of tendon attachment or corticosteroid treatment preceded triceps tendon disruption. Radiographic signs or histopathology suggestive of a chronic tendinopathy was common. All cases underwent surgical repair involving a tendon suture pattern, 12 of which were secured through bone tunnels. Immobilisation was used in all cases in the form of transarticular external skeletal fixation (TAESF) (8/9 dogs) or spica splint (four cats, two dogs; in one dog a TAESF was applied after complications associated with the spica splint). Complications occurred in 11 cases (17 total complications), frequently associated with the immobilisation method. One case had traumatic tendon rerupture two years following surgery. A wound at presentation was associated with the development of multiple complications. Nine cases had long-term follow-up; five achieved normal function, four achieved acceptable function. Despite the complications, overall return to subjective normal or acceptable function, as assessed by the owners, was achieved in the majority of cases.