Morphometric Approach Research Articles

A first glimpse at the influence of body mass in the morphological integration of the limb long bones: an investigation in modern rhinoceroses.

The appendicular skeleton of tetrapods is a particularly integrated structure due to the shared developmental origin or similar functional constraints exerted on its elements. Among these constraints, body mass is considered strongly to influence its integration but its effect on shape covariation has rarely been addressed in mammals, especially in heavy taxa. Here, we propose to explore the covariation patterns of the long bones in heavy animals and their link to body mass. We investigate the five modern rhinoceros species, which display an important range of bodyweight. We used a 3D geometric morphometric approach to describe the shape covariation of the six bones composing the stylopodium and zeugopodium both among and within species. Our results indicate that the appendicular skeleton of modern rhinos is a strongly integrated structure. At the interspecific level, the shape covariation is roughly similar between all pairs of bones and mainly concerns the muscular insertions related to powerful flexion and extension movements. The forelimb integration appears higher and more related to body mass than that of the hind limb, suggesting a specialization for weight support. The integration of the stylopodium elements does not seem to relate to body mass in our sample, which suggests a greater effect of shared developmental factors. Conversely, the covariation of the zeugopodium bones seems more associated with body mass, particularly for the radius-ulna pair. The fibula appears poorly integrated with other bones, especially within non-Rhinoceros species, which may represent a case of parcellation due to a functional dissociation between the hind limb bones. The exploration of the integration patterns at the intraspecific level also highlights a more prominent effect of age over individual body mass on shape covariation within C.simum. This study lends support to previous hypotheses indicating a link between high body mass and high integration level.

Treatment of Acromegalic Osteopathy in Real-life Clinical Practice: The BAAC (Bone Active Drugs in Acromegaly) Study.

Vertebral fractures (VFs) are a frequent complication of acromegaly, but no studies have been so far published on effectiveness of antiosteoporotic drugs in this clinical setting. To evaluate whether in real-life clinical practice bone active drugs may reduce the risk of VFs in patients with active or controlled acromegaly. Retrospective, longitudinal study including 9 tertiary care endocrine units. Two hundred and forty-eight patients with acromegaly (104 males; mean age 56.00 ± 13.60 years) were evaluated for prevalent and incident VFs by quantitative morphometric approach. Bone active agents were used in 52 patients (20.97%) and the median period of follow-up was 48 months (range 12-132). During the follow-up, 65 patients (26.21%) developed incident VFs in relationship with pre-existing VFs (odds ratio [OR] 3.75; P < .001), duration of active acromegaly (OR 1.01; P = .04), active acromegaly at the study entry (OR 2.48; P = .007), and treated hypoadrenalism (OR 2.50; P = .005). In the entire population, treatment with bone active drugs did not have a significant effect on incident VFs (P = .82). However, in a sensitive analysis restricted to patients with active acromegaly at study entry (111 cases), treatment with bone active drugs was associated with a lower risk of incident VFs (OR 0.11; P = .004), independently of prevalent VFs (OR 7.65; P < .001) and treated hypoadrenalism (OR 3.86; P = .007). Bone active drugs may prevent VFs in patients with active acromegaly.

The morphological affinity of the Early Pleistocene footprints from Happisburgh, England, with other footprints of Pliocene, Pleistocene, and Holocene age

Fossil hominin footprints provide a direct source of evidence of locomotor behavior and allow inference of other biological data such as anthropometrics. Many recent comparative analyses of hominin footprints have used 3D analytical methods to assess their morphological affinities, comparing tracks from different locations and/or time periods. However, environmental conditions can sometimes preclude 3D digital capture, as was the case at Happisburgh (England) in 2013. Consequently, we use here a 2D geometric morphometric approach to investigate the evolutionary context of the Happisburgh tracks. The comparative sample of hominin tracks comes from eight localities that span a broad temporal range from the Pliocene to Late Holocene. The results show disparity in the shapes of tracks ascribed to hominins from the Pliocene (presumably Australopithecus afarensis), Pleistocene (presumably Homo erectus and Homo antecessor), and Holocene (Homo sapiens). Three distinct morphological differences are apparent between time samples: changes in adduction of the hallux, changes in the shape and position of the medial longitudinal arch impression, and apparent changes in foot proportions. Linear dimensions classified the potential H. antecessor tracks from Happisburgh as being most similar to the presumed H. erectus prints from Ileret. We demonstrate using 2D geometric morphometric methods and linear dimensions that the Happisburgh tracks are morphologically similar to other presumed Homo tracks and differ from the Laetoli footprints. The probable functional implications of these results fit well with previous comparative analyses of hominin tracks at other sites.

Statistical shape analysis of corpus callosum in restless leg syndrome

ABSTRACT Objectives In this study we aimed to investigate corpus callosum shape differences between restless leg syndrome patients and healthy controls, and to determine whether disease severity and duration are indicators for corpus callosum deformation in RLS patients. Methods This study was conducted using the magnetic resonance imaging scans of 33 restless leg syndrome patients and 33 control subjects. Landmarks were marked on the digital images and callosal landmark coordinate data were used to assess shape difference by performing Generalized Procrustes analysis. The shape deformation from controls to the patients was evaluated performing the Thin Plate Spline approach. Results There was a statistically significant shape difference between the groups. Highest deformation was determined at the posterior midbody of the corpus callosum. Growth curve analyses showed that with the increase in disease duration and severity, the CC size decreased. Discussion The present study demonstrated callosal shape differences in restless leg syndrome using a landmark-based geometric morphometric approach, considering the topographic distribution of corpus callosum for the first time.

Skull morphometric characters in parrots (Psittaciformes)

Abstract Parrots (Psittaciformes) are a unique and diverse avian group and vary tremendously in size, shape, and colour. Mainly distributed throughout the tropics and subtropics, most species of parrots are largely or exclusively arboreal with several exceptions. The species also differ in diet and habitat, which led to different musculoskeletal adaptations of the skull. However, parrots have conspicuous generalized external features; in this recent study, we tried to increase our knowledge of the cranial shape and foraging habits. A geometric morphometric approach was used to analyse two-dimensional cranial landmarks. We used principal component (PC) analyses on measurements that may be related to diet. The PCs described the relative height of the cranium, the relative length and curvature of the beak, differences in the orientation and curvature of the lacrimal bone and the upper margin of orbits, variation in the size and position of the palatine bone and the relative width of the cranium, and variation in the relative size of the neurocranium compared to the viscerocranium. The dietary categories overlap in the morphospace but the analysis in lateral and ventral view resulted in significant differences.

Growth and Sexual Dimorphism of the Hyoid Body in Macaca mulatta

The hyoid contributes to a range of functional behaviors such as breathing, swallowing, and vocalization. Among nonhuman primates, hyoid morphology and position show taxonomic differences. For example, cercopithecoid hyoids are more anatomically constrained than hominoid hyoids, which may influence their morphology. While most of the existing literature on the hyoid in nonhuman primates compares morphological differences among species, studies of intraspecific hyoid morphological variation are scarce. This study used a geometric morphometric approach to examine the effects of age and sex on hyoid morphology in Macaca mulatta. The sample comprised 154 skeletal specimens housed at the University of Puerto Rico’s Caribbean Primate Research Center, representing both sexes and an age range of 1–25 years old. I collected three-dimensional landmark coordinate data from the cranium, mandible, and hyoid body of each specimen and tested the effects of age and sex on hyoid morphology through principal components analysis and full factorial analyses. Hyoid shape correlated strongly with age but not sex. Hyoid shape and size correlated strongly with both life history stage and age class. While the hyoid appears to grow within expected body size parameters, hyoid morphology is not fully isometric. Rather, the hyoid exhibits superoinferior lengthening and upward rotation through postnatal ontogeny, with notable upward rotation of the superior surface occurring at 1–4 years of age. As maturational processes such as vocal tract lengthening impose age-linked constraints on vocal behavior, these findings suggest that the hyoid grows in relation to surrounding vocal tract anatomy, and that hyoid shape may contribute to structural support for age-linked vocalization.

Replication of a hippocampus specific effect of the tescalcin regulating variant rs7294919 on gray matter structure

While the hippocampus remains a region of high interest for neuropsychiatric research, the precise contributors to hippocampal morphometry are still not well understood. We and others previously reported a hippocampus specific effect of a tescalcin gene (TESC) regulating single nucleotide polymorphism (rs7294919) on gray matter volume. Here we aimed to replicate and extend these findings. Two complementary morphometric approaches (voxel based morphometry (VBM) and automated volumetric segmentation) were applied in a well-powered cohort from the Marburg-Münster Affective Disorder Cohort Study (MACS) including N=1137 participants (n=636 healthy controls, n=501 depressed patients). rs7294919 homozygous T-allele genotype was significantly associated with lower hippocampal gray matter density as well as with reduced hippocampal volume. Exploratory whole brain VBM analyses revealed no further associations with gray matter volume outside the hippocampus. No interaction effects of rs7294919 with depression nor with childhood trauma on hippocampal morphometry could be detected. Hippocampal subfield analyses revealed similar effects of rs7294919 in all hippocampal subfields. In sum, our results replicate a hippocampus specific effect of rs7294919 on brain structure. Due to the robust evidence for a pronounced association between the reported polymorphism and hippocampal morphometry, future research should consider investigating the potential clinical and functional relevance of the reported association.

Morphometry of a glacier-linked esker in NW Tempe Terra, Mars, and implications for sediment-discharge dynamics of subglacial drainage

We present a systematic, metre-scale characterisation of the 3D morphometry of an esker on Mars, and the first attempt to reconstruct the multi-stage dynamics of esker formation on Mars. Eskers are sinuous ridges comprising sediment deposited by meltwater draining through ice-confined tunnels within or beneath glaciers. Detailed morphometric insights into eskers on Mars are important for (i) informing morphometric tests of whether sinuous ridges elsewhere on Mars are eskers, and (ii) informing modelling experiments which aim to reconstruct the glaciological and environmental controls on esker formation on Mars. We use a digital elevation model generated from High Resolution Imaging Science Experiment (HiRISE) images to characterise the height and width of an extremely rare esker associated with a late-Amazonian-aged viscous flow feature (debris-covered glacier) in NW Tempe Terra, Mars. Our measurements suggest that the NW Tempe Terra esker is a ‘stacked’ formation comprising an underlying ‘lower member’ ridge that is superposed by a narrower ‘upper member’ ridge. We used a novel morphometric approach to test whether the apparent stacking records two distinct esker deposition regimes (either within the same drainage episode, or within temporally-separated drainage episodes). This approach posits that esker crest morphology is controlled by primary esker formation processes and, by extension, that portions of eskers with similar crest morphologies should have similar morphometric relationships. We predicted the morphometric relationships described by the constituent upper and lower member ridges based on ‘reference relationships’ observed for morphologically-similar portions of the esker where no evidence of stacking was observed. Our observations corresponded well with the predicted relationships, supporting our stacked esker hypothesis. We propose conceptual models, which invoke spatial and temporal variations in sediment supply and meltwater discharge, to explain the stacked morphology. These models are informed by morpho-sedimentary relationships observed along eskers on Earth.

Morphological and molecular characterisation of Telotylenchus tamariscus n. sp. (Nematoda: Telotylenchinae) recovered from Khuzestan, south-western Iran

Summary An undescribed species from the rhizosphere of tamarisk, Tamarix passerinoides, Telotylenchus tamariscus n. sp., is illustrated and described based on morphological, morphometric and molecular approaches. The new species is characterised by female characters including body size of ca 1 mm, areolated lateral fields, cephalic region rounded, distinctly set off from the body contour, stylet 19.5 (18.5-20.5) μm long with posteriorly directed basal knobs, pharyngeal glands overlapping intestine dorso-laterally, subcylindrical tail bearing 32 (25-37) cuticular annuli and ending in an annulated terminus, and male spicules and gubernaculum 27 (25-29) and 13 (12.5-14.5) μm long, respectively. Morphologically, our population comes close to several known species of the genus, including T. avaricus, T. aerolatus, T. indicus, T. ventralis, T. paaloofi and T. namibiensis. In the 18S rRNA phylogenetic tree, it occupied a phylogenetic position in close affinity with two sequences of T. ventralis. In the 28S rRNA tree, the genus Telotylenchus did not form a monophyletic group, our isolate clustering with an unknown population of Histotylenchus and four isolates of Tylenchorhynchus mediterraneus in a clade well separated from another clade that included three other isolates tentatively named as Telotylenchus sp.

A Morphometric Approach in South American Stipoids with Plumose and Pappus-like Awns

Abstract—Within grasses, the tribe Stipeae is highly specialized by the presence of only one fruit per spikelet and characterized by the diversity in the ornamentation of the floret. Our aim was to analyze similarities and differences based on multi- and univariate analyses among closely related species in American Stipeae: Jarava species with plumose-like awns and species of Pappostipa with pappus-like awns. Ordination analyses (principal coordinate analysis and cluster analysis) were used to determine major groupings, while significant differences among groups were tested by multivariate analysis of variance (MANOVA) and univariate analysis based on generalized linear models (GLM). Based on morphological similarities, we delimited five groups. The presence of a small floret characterized Jarava annua, J. media, and J. plumosula, although J. annua was clearly distinguished by the distribution of hairs in the awn column. Jarava subplumosa and J. psylantha were characterized by the pubescence of the culm, the length of the floret callus, the length of the awn subule, and the length of the awn hairs. Pappostipa was distinctive by having hairs only in the awn column that resemble a pappus while Jarava neaei + J. pogonathera presented the longest inflorescences and hairs only on the awn subule, resembling a feather. As a result, we present a key to taxa and descriptions to characterize and identify species within the Jarava-Pappostipa group with plumose and pappus-like awns.

SAT-389 Clinical and Biochemical Characterization of Risk Factors for Vertebral Fractures in Patients with Hypoparathyroidism

Background: Persistent hypoparathyroidism (PH) is a rare disease due to an impaired secretion of PTH, mostly occurring as a complication of total thyroidectomy. Calcium and calcitriol are currently the most common and inexpensive therapies, although not all the patients easily achieve control of the disease. Recently, our group has reported that BMI at diagnosis can predict calcitriol resistance in PH. Very few studies have been performed with fractures as primary endpoint in hypoparathyroidism, and we still not know if PH could be predisposing to an increased risk of morphometric fractures and possible clinical and biochemical predicting factors. Patients and methods: To that end we retrospectively evaluated the anthropometric, biochemical and fracture characteristics in 71 consecutive patients with PH (F/M= 62/9; median age 58.7 yrs, range: 29-87; 67 with post-surgical PH and 4 with autoimmune PH). All patients were hypoparathyroid from at least one year (median duration of disease: 9 yrs., range: 1-41) and were under standard treatment with calcium and active vitamin D analogs (calcitriol). For each patient anthropometric data (BMI=kg/m2; N= Normal weight patients <25; OO= Obese and overweight patients with BMI > 25) were collected, as well as biochemical parameters, such as calcium (mg/dl) and 25 OH vitamin D (25OHD expressed as ng/ml). We considered well controlled (C) patients with calcium between 8.2 and 9.2 mg/dl and not controlled (NC) under 8.2 or above 9.2 mg/dl. Vertebral fractures (VF) were assessed by a quantitative morphometric approach by using images provided by DXA and classified according to Genant classification. Results: Thirteen out of 71 patients (18%) were fractured. We showed a positive linear correlation in the overall population between BMI and calcitriol intake (p=0.006, CI 95% [1.2-6.9]) while no significant difference in prevalence of VF in OO vs N group (8/40 vs 5/31, p=0.76) was found. However, almost half (6/13, 45%) of patients with VF were OO NC. Moreover, 86% of NC vs only 30% of C fractured patients (6/7 vs 2/6) were OO Discussion: We report a high prevalence of VF in hypoparathyroidism. Moreover, we confirm that increased BMI is associated with higher needs of calcitriol to obtain calcium control. Interestingly, our data suggest for the first time that OO hypoparathyroid patients with NC disease are those at highest risk of fracture. Therefore, in this subset of patients a more intensive and proactive biochemical and bone monitoring should be adviced if these results will be confirmed in larger studies.

Categorical versus geometric morphometric approaches to characterizing the evolution of morphological disparity in Osteostraci (Vertebrata, stem Gnathostomata)

AbstractMorphological variation (disparity) is almost invariably characterized by two non‐mutually exclusive approaches: (1) quantitatively, through geometric morphometrics; and (2) in terms of discrete, ‘cladistic’, or categorical characters. Uncertainty over the comparability of these approaches diminishes the potential to obtain nomothetic insights into the evolution of morphological disparity and the few benchmarking studies conducted so far show contrasting results. Here, we apply both approaches to characterizing morphology in the stem‐gnathostome clade Osteostraci in order to assess congruence between these alternative methods as well as to explore the evolutionary patterns of the group in terms of temporal disparity and the influence of phylogenetic relationships and habitat on morphospace occupation. Our results suggest that both approaches yield similar results in morphospace occupation and clustering, but also some differences indicating that these metrics may capture different aspects of morphology. Phylomorphospaces reveal convergence towards a generalized ‘horseshoe’‐shaped cranial morphology and two strong trends involving major groups of osteostracans (benneviaspidids and thyestiids), which probably reflect adaptations to different lifestyles. Temporal patterns of disparity obtained from categorical and morphometric approaches appear congruent, however, disparity maxima occur at different times in the evolutionary history of the group. The results of our analyses indicate that categorical and continuous data sets may characterize different patterns of morphological disparity and that discrepancies could reflect preservational limitations of morphometric data and differences in the potential of each data type for characterizing more or less inclusive aspects of overall phenotype.

A Combined Morphometric and Statistical Approach to Assess Nonmonotonicity in the Developing Mammary Gland of Rats in the CLARITY-BPA Study.

Background:The Consortium Linking Academic and Regulatory Insights on Bisphenol-A (CLARITY-BPA) is a rare collaboration of guideline-compliant (core) studies and academic hypothesis-based studies to assess the effects of bisphenol A (BPA).Objectives:We aimed to a) determine whether BPA showed effects on the developing rat mammary gland using new quantitative and established semiquantitative methods in two laboratories, b) develop a software tool for automatic evaluation of quantifiable aspects of the mammary ductal tree, and c) compare those methods.Methods:Sprague-Dawley rats were exposed to BPA, vehicle, or positive control [ethinyl estradiol (EE2)] by oral gavage beginning on gestational day (GD)6 and continuing with direct dosing of the pups after birth. There were two studies: subchronic and chronic. The latter used two exposure regimes, one stopping at postnatal day (PND)21 (stop-dose) the other continuing until tissue harvest (continuous). Glands were harvested at multiple time points; whole mounts and histological specimens were analyzed blinded to treatment.Results:The subchronic study’s semiquantitative analysis revealed no significant differences between control and BPA dose groups at PND21, whereas at PND90 there were significant differences between control and the lowest BPA dose and between control and the lowest EE2 dose in animals in estrus. Quantitative, automatized analysis of the chronic PND21 specimens displayed nonmonotonic BPA effects, with a breaking point between the 25 and body weight (BW) per day doses. This breaking point was confirmed by a global statistical analysis of chronic study animals at PND90 and 6 months analyzed by the quantitative method. The BPA response was different from the EE2 effect for many features.Conclusions:Both the semiquantitative and the quantitative methods revealed nonmonotonic effects of BPA. The quantitative unsupervised analysis used 91 measurements and produced the most striking nonmonotonic dose–response curves. At all time points, lower doses resulted in larger effects, consistent with the core study, which revealed a significant increase of mammary adenocarcinoma incidence in the stop-dose animals at the lowest BPA dose tested. https://doi.org/10.1289/EHP6301

Multi-dimensional machine learning approaches for fruit shape phenotyping in strawberry.

BackgroundShape is a critical element of the visual appeal of strawberry fruit and is influenced by both genetic and non-genetic determinants. Current fruit phenotyping approaches for external characteristics in strawberry often rely on the human eye to make categorical assessments. However, fruit shape is an inherently multi-dimensional, continuously variable trait and not adequately described by a single categorical or quantitative feature. Morphometric approaches enable the study of complex, multi-dimensional forms but are often abstract and difficult to interpret. In this study, we developed a mathematical approach for transforming fruit shape classifications from digital images onto an ordinal scale called the Principal Progression of k Clusters (PPKC). We use these human-recognizable shape categories to select quantitative features extracted from multiple morphometric analyses that are best fit for genetic dissection and analysis.ResultsWe transformed images of strawberry fruit into human-recognizable categories using unsupervised machine learning, discovered 4 principal shape categories, and inferred progression using PPKC. We extracted 68 quantitative features from digital images of strawberries using a suite of morphometric analyses and multivariate statistical approaches. These analyses defined informative feature sets that effectively captured quantitative differences between shape classes. Classification accuracy ranged from 68% to 99% for the newly created phenotypic variables for describing a shape.ConclusionsOur results demonstrated that strawberry fruit shapes could be robustly quantified, accurately classified, and empirically ordered using image analyses, machine learning, and PPKC. We generated a dictionary of quantitative traits for studying and predicting shape classes and identifying genetic factors underlying phenotypic variability for fruit shape in strawberry. The methods and approaches that we applied in strawberry should apply to other fruits, vegetables, and specialty crops.

The Cerro Guanaco mass movements: A geophysical and morphometric approach on a megalandslide in the Fuegian Andes (Southern Patagonia)

The Fuegian Andes, in the southernmost part of South America, are characterized by a relatively young deglacial landscape, where the glacial erosive relief is strongly influenced by regional-scale geological structures, resulting in deep longitudinal valleys with steeply dipping hillslopes. The rock-slope stability response to receding ice masses and the contribution of the gravitational processes in landscape evolution of the southernmost Andes, however, have not been assessed so far. The remoteness of the region, comprising a mountainous area hardly to access and piedmont and valley floors densely covered by forest, peatbogs or water bodies might partly explain the lack of such studies. Therefore, the objective of this contribution is to document for the first time the occurrence of massive slope failures in the Fuegian Andes using a multidisciplinary approach. This involves the use of indirect methods such as applied geophysics and landscape morphometrics. The southwest-facing slope of Cerro Guanaco, near Ushuaia, hosts several slope failures, but a massive failure stands out. The morphostructural approach allowed the geometrical description of the main dimensional characteristics of the first megalandslide recognized in the Fuegian Andes, which involved almost 1,2 km3 of material. On the other hand, the geophysical data has proved valuable in estimating the depth and characteristic of the buried detachment surface. The slope failure consisted of an initial translational movement followed by secondary slides and was developed shortly after the glacier recession. The gravitational processes represent an important element in the Fuegian deglacial landscape evolution.

Rapid divergent coevolution of Sinopotamon freshwater crab genitalia facilitates a burst of species diversification.

One of the most striking radiations in brachyuran evolution is the considerable morphological diversification of the external reproductive structures of primary freshwater crabs: the male first gonopod (G1) and the female vulva (FV). However, the lack of quantitative studies, especially the lack of data on female genitalia, has seriously limited our understanding of genital evolution in these lineages. Here we examined 69 species of the large Chinese potamid freshwater crab genus Sinopotamon Bott, 1967 (more than 80% of the described species). We used a landmark‐based geometric morphometric approach to analyze variation in the shape of the G1 and FV, and to compare the relative degree of variability of the genitalia with non‐reproductive structures (the third maxillipeds). We found rapid divergent evolution of the genitalia among species of Sinopotamon when compared to non‐reproductive traits. In addition, the reconstruction of ancestral groundplans, together with plotting analyses, indicated that the FV show the most rapid divergence, and that changes in FV traits correlate with changes in G1 traits. Here we provide new evidence for coevolution between the male and female external genitalia of Sinopotamon that has likely contributed to rapid divergent evolution and an associated burst of speciation in this lineage.

A Combined Geometric Morphometric and Discrete Element Modeling Approach for Hip Cartilage Contact Mechanics

Finite element analysis (FEA) provides the current reference standard for numerical simulation of hip cartilage contact mechanics. Unfortunately, the development of subject-specific FEA models is a laborious process. Owed to its simplicity, Discrete Element Analysis (DEA) provides an attractive alternative to FEA. Advancements in computational morphometrics, specifically statistical shape modeling (SSM), provide the opportunity to predict cartilage anatomy without image segmentation, which could be integrated with DEA to provide an efficient platform to predict cartilage contact stresses in large populations. The objective of this study was, first, to validate linear and non-linear DEA against a previously validated FEA model and, second, to present and evaluate the applicability of a novel population-averaged cartilage geometry prediction method against previously used methods to estimate cartilage anatomy. The population-averaged method is based on average cartilage thickness maps and therefore allows for a more accurate and individualized cartilage geometry estimation when combined with SSM. The root mean squared error of the population-averaged cartilage geometry predicted by SSM as compared to the manually segmented cartilage geometry was 0.31 ± 0.08 mm. Identical boundary and loading conditions were applied to the DEA and FEA models. Predicted DEA stress distribution patterns and magnitude of peak stresses were in better agreement with FEA for the novel cartilage anatomy prediction method as compared to commonly used parametric methods based on the estimation of acetabular and femoral head radius. Still, contact stress was overestimated and contact area was underestimated for all cartilage anatomy prediction methods. Linear and non-linear DEA methods differed mainly in peak stress results with the non-linear definition being more sensitive to detection of high peak stresses. In conclusion, DEA in combination with the novel population-averaged cartilage anatomy prediction method provided accurate predictions while offering an efficient platform to conduct population-wide analyses of hip contact mechanics.

Quantitative accuracy and 3D biometric matching of 388 statistically estimated facial approximations of live subjects

Abstract Objective A geometric morphometric approach for testing the metric accuracy of a computerized facial approximation program is presented. Materials and methods This study uses a leave-one-out procedure to generate average approximations (not adjusted for weight/age) for each individual in the ReFace reference database (n = 388), consisting of eight sex/ancestry groups (both sexes for each: African, Asian, European, Hispanic). Quantitative comparisons of corresponding three-dimensional (3D) known faces and approximations were analyzed using 66 inter-landmark distances (ILDs) derived from twelve interior facial landmarks. Results and conclusions Average signed errors per ILD ranged from -0.67 mm to 1.92 mm, with most errors indicating smaller ILDs in approximations. For all individual ILD errors combined, 99.5% were within ± 10.0 mm, 90.8% were within ± 5.0 mm, 64.6% were within ± 2.5 mm, and 30.2% were within ± 1.0 mm. The largest errors were associated with cheilion and indicated underestimated mouth widths by an overall average of 1.92 mm (SD = 3.99 mm). A statistical matching model that modeled performance of automated facial recognition correctly identified 73–88% of known-approximation pairs as matches. The accuracy and matching results suggest that facial features are highly influenced by the underlying craniofacial skeleton regardless of weight/age variations, the matching model is predictive of automated facial recognition performance, and that ReFace approximations may be sufficiently accurate to biometrically match unidentified decedents to missing persons.

Fish Species Identification Using the Rhombic Squamation Pattern

The shape of fish scales is to a considerable degree species-specific, making it possible to identify species using only one scale per specimen. However, the shape of the rhombic lamination pattern has not been considered to identify species. This study used geometric morphometric statistical approaches to address two specific questions: (1) whether the rhombic lamination pattern of fish scales along the longitudinal axis varies within species and sex and (2) how many fish scales of the rhombic squamation pattern should be considered to obtain an adequate identification. These questions were assessed with Mancova and cross-validated quadratic discriminant analysis (DA) using the rhombus of one, three and six scales, and six, 14 and 26 landmarks, respectively, in order to discriminate between two co-generic species, Mugil cephalus and M. curema. The proportions of the total shape variance explained by the total length and the centroid size were 2.3, 11.8 and 10.5% and 4.2, 5.1 and 5.4% for 1, 3 and 6 scales, respectively. Analyses were carried out on the shape and the form (shape plus size). The Mancova and DA analyses were found to be effective in detecting differences in scale pattern shape between species (except in the case of 3 scales; p=0.079 for the shape and p=0.065 for the form), whereas no differences were recorded between size and sex in all cases. The findings indicate that a good identification of species is possible, with no significant differences when using shape or form. The discriminant analyses provided values of 75.8, 75.0 and 73.4% based on the shape, and of 72.7, 75.8 and 75.0% based on the form, for 1, 3 and 6 scales respectively. Thus, it is possible to obtain a rapid and reliable identification of species using the rhombus of one scale only without considering the size. This is a useful finding in practical terms since scaling requires data on length. In addition, the finding of a suitable discrimination using only the rhombus of one scale raises the possibility of using an ocular adaptor on a camera or mobile, allowing many individuals to be easily screened without having to collect scales.

Reproductive compatibility and morphological characterization of local populations of the larval endoparasitoid Pseudapanteles dignus in Argentina

In hymenopteran parasitoids, isolated geographic populations can show morphological variation and reproductive incompatibility that may lead to failures in biological control programs when they are intended to be used as biocontrol agents. Through a classical morphometric approach we confirm the specific identity of three local populations of the larval arrhenotokous endoparasitoid Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae) of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), from three main tomato producing areas of Argentina. Moreover, we examined reproductive compatibility by outcrossing the three populations. Morphometric differences among P. dignus biotypes were found but no evidences of mating incompatibility among them existed. This laboratory study contributes with relevant information to the original description of the species P. dignus and has significant implications for T. absoluta biological control using this parasitoid in tomato crops from different regions of Argentina.