Width Distance Research Articles

Morphology of the patellar tendon and its insertion sites using three-dimensional computed tomography: A cadaveric study

BackgroundTo clarify, with three-dimensional (3D) images, the morphological properties of the patellar tendon and both of its insertion sites. MethodsThirty-two human cadaveric left knees were evaluated, and 3D computed tomography images were created. These images were used to analyse the morphology of both insertion sites of the patellar tendon, and the width, length and thickness of each region of the patellar tendon. ResultsThe insertion sites of the patellar tendon on the patellar and tibial sides were V-shaped and crescent-shaped, respectively, with the respective bony apexes located at 44.5 ± 2.2% (standard deviation) and 35.5 ± 2.8% of the tendon width from its medial edge. The proximal, central and distal widths of the patellar tendon were 29.9 ± 2.7 mm, 27.3 ± 2.5 mm and 25.0 ± 2.4 mm, respectively. The length of the patellar tendon was shortest at 40.6% ± 6.7% of the central width and gradually became longer toward both edges. The patellar tendon was thickest in the central portion of 40–75% and gradually became thinner toward both edges. ConclusionsThe morphological properties of the patellar tendon and its insertion sites on both the patellar and tibial sides were consistent. These findings indicate that the characteristics of the bone–patellar tendon–bone graft markedly depend on the location from which it is harvested, and that these characteristics contribute to predicting the length, width and shapes of the bone plugs of the graft when performing bone–patellar tendon–bone surgery.

High-Grade Dural Arteriovenous Fistulas

Dural arteriovenous fistulas (DAVF) are commonly encountered lesions that can be treated both transvenously, transarterially or using acombined approach. Transvenous coil embolization of DAVF is arecognized treatment option but can be challenging. In this context this article presents clinical experience using the Kaneka ED10 ExtraSoft coils in combination with the Marathon microcatheter to treat high grade DAVF. The physical properties of these coils and the microcatheter were also determined. All patients with high grade DAVF treated with the Marathon and the Kaneka ED COIL ∞10 ExtraSoft coils were retrospectively identified. The clinical presentation, location, grade of the lesion, clinical and radiological follow-up data were recorded. Bench side studies were performed to determine the physical properties of the Marathon catheter in comparison to the SL10 and Headway Duo as well the maximum width of the Kaneka pusher wire in comparison to Hypersoft, Target and Axium Prime coils. Atotal of 8patients with 9DAVF with 3Cognard3 and 6Cognard4 lesions were identified. All the DAVF's were occluded either at the end of the procedure or on follow-up imaging. On bench side tests the Marathon microcatheter had the most flexible distal tip and distal shaft in comparison to the SL10 and Headway Duo. The proximal shaft of the Marathon was stiffer than the SL10. The Kaneka ED COIL ∞10 ExtraSoft had the smallest distal width and were the only coils tested that could be deployed through aMarathon microcatheter. The combination of the Marathon microcatheter and Kaneka ED COIL ∞10 ExtraSoft is useful for the treatment of high grade DAVF.

Evolution of hindlimb bone dimensions and muscle masses in house mice selectively bred for high voluntary wheel-running behavior.

We have used selective breeding with house mice to study coadaptation of morphology and physiology with the evolution of high daily levels of voluntary exercise. Here, we compared hindlimb bones and muscle masses from the 11th generation of four replicate High Runner (HR) lines of house mice bred for high levels of voluntary wheel running with four non-selected control (C) lines. Mass, length, diameter, and depth of the femur, tibia-fibula, and metatarsal bones, as well as masses of gastrocnemius and quadriceps muscles, were compared by analysis of covariance with body mass or body length as the covariate. Mice from HR lines had relatively wider distal femora and deeper proximal tibiae, suggesting larger knee surface areas, and larger femoral heads. Sex differences in bone dimensions were also evident, with males having thicker and shorter hindlimb bones when compared with females. Several interactions between sex, linetype, and/or body mass were observed, and analyses split by sex revealed several cases of sex-specific responses to selection. A subset of the HR mice in two of the four HR lines expressed the mini-muscle phenotype, characterized mainly by an ∼50% reduction in hindlimb muscle mass, caused by a Mendelian recessive mutation, and known to have been under positive selection in the HR lines. Mini-muscle individuals had elongated distal elements, lighter and thinner hindlimb bones, altered 3rd trochanter muscle insertion positions, and thicker tibia-fibula distal widths. Finally, several differences in levels of directional or fluctuating asymmetry in bone dimensions were observed between HR and C, mini- and normal-muscled mice, and the sexes. This study demonstrates that skeletal dimensions and muscle masses can evolve rapidly in response to directional selection on locomotor behavior.

The Diagnostic Value of Radius Bone in Forensic Identification Using Radiographic Images in Iranian Population

Background: Identification is an important and difficult part of forensic medicine. This study investigated the accuracy of using Maximum Length of Radius (MLR) and Maximum distal Width of Radius (MWR) measurements in radiographic images to determine sex in Iranian population. Moreover, the correlation between these parameters was evaluated. Methods: This study was carried out on radiographic images of 90 adults (45 men and 45 women) over 20 years old. The sample population was divided into three age groups of 20-34, 35-49, and ≥50 years old. Maximum length and width of radius were measured digitally and then analyzed. Results: The mean values of both measurements in men were more than those in women and radius length decreased with increasing age. The accuracy of these two measured parameters in determining sex was similar (83.3%). Moreover, the correlation values (r) between MLR and MWR were 0.49 (P<0.0001) in total studied population. Conclusion: Sex can be determined using MLR or MWR with relatively high accuracy. However, regarding the intermediate correlation between these values, it is not enough to estimate the corresponding MLR from MWR.

One-stage laser-microtextured implants immediately placed in the inter-radicular septum of molar fresh extraction sockets associated with GBR technique. A case series study.

BackgroundThe outcome of one-stage trans-mucosal immediate implants with simultaneous guided bone regeneration (GBR) technique has become highly predictable. Furthermore, when this approach is performed to place one-stage implants into the inter-radicular septum of fresh extraction sockets in the molar region, the risk of incorrect emergence profile and off-angle loading is reduced. The aim of the present study was to clinically evaluate the horizontal hard and soft tissue changes, and radiographically the vertical socket walls remodeling, and the early peri-implant marginal bone loss (EMBL) following the placement of immediate one-stage implants in the inter-radicular septum of molar fresh extraction sockets, associated with a collagen membrane.Material and MethodsTwenty patients were selected to receive a one-stage implant with laser-microtextured collar surface into the inter-radicular septum of a fresh molar extraction sockets, associated with a simultaneous placement of a collagen membrane. Intraoral radiographs and model casts were used for the evaluation. Correlation between the amount of the keratinized tissue thickness (KTT) with EMBL was also analyzed.ResultsAfter 4 months, the vertical radiographic mesial and distal EMBL around implants was of 0.06 ±0.01 mm and 0.04±0.02 mm, respectively, with no statistically significant difference between T0 and T1 (P >0.05). No statistical differences were found also for each radiographic measure used for the examination of implant sites vertical bone changes (p >0.05). Clinically, horizontal changes of the bucco-lingual central width were found statistically significant (p<0.05), whereas no statistical differences were found for bucco-lingual mesial and distal width changes (p >0.05). In addition, no statistically significant correlation between EMBL and the amount of KTT was found (P >0.05).ConclusionsResults suggest that the immediate placement of one-stage laser-microtextured implants could provide advantages in preserving the extraction socket’s hard and soft tissue remodeling, and the peri-implant marginal bone level before the prosthetic loading. Key words:One-stage implant, laser-microtextured collar surface, GBR, collagen membrane.

Validity and Reproducibility of Digital Models Obtained by Cone Beam Computed Tomography Imaging

Introduction: Impression making and fabrication of plaster models serve as a basis for documentation, diagnosis and treatment planning. Model analysis is used routinely in orthodontics and is a key factor for treatment planning and review of orthodontic progress. Recently newer technologies in imaging and digitalisation have made it possible to obtain 3-Dimensional (3D) virtual models. Virtual models score over plaster models with respect to accessibility, storage and long life. However, there are concerns over its accuracy and reproducibility. Aim: To evaluate the accuracy of three dimensional digital models obtained from Cone Beam Computed Tomography (CBCT). Materials and Methods: This was an ex-vivo study. Thirty dental models of patients were selected and scanning of these models were done using CBCT. Means and standard deviations of the space analysis measurements were calculated by using both plaster and digital models. Statistical analyses were used to investigate the accuracy and repeatability of the methods studied using Statistical Package of Social Sciences (SPSS) 20.0. Paired t-tests for both mean and standard errors were calculated. R esults: The results for all 30 maxillary and mandibular models were similar. There was a statistically significant difference in calculating sum of ten teeth for both maxillary and mandibular teeth between the plaster and dental digital models and in mesio distal measurements between digital and plaster dental models. C onclusion: Digital models provide a more accurate measurement of mesio distal width of tooth with a statistically significant difference of (p-value=0.002).

Drum Evaluation of Broilers Over 20 Years of Selection

ObjectivesAs a result of genetic selection pressures, economically important traits continue to make gains in fast growing boilers. To understand the impact that has taken place over time on profitable traits, such as live weight, as well as indirectly selected traits, whole leg and tibia parameters of 2 genetic broiler lines representing the 1995 and 2015 broiler maintained at the University of Arkansas were compared.Materials and MethodsOne hundred 20 broilers, evenly split between the 1995 RAN and 2015 RAN lines, were reared straight-run with ab libitum access to industry standard feed and water (IACUC Approval #15039). Fifteen birds were weighed, then euthanized at each time point from each line (d 0, d 14, d 28, and d 42). Left legs were disarticulated, weighed and cleaned of flesh and tendons. The following tibia measurements were collected; tibia weight, tibia lengths, proximal width-frontal, distal width-frontal, midpoint width, proximal width-sagittal, distal width-sagittal. Max load, load break, load extension, and compressive strain was calculated for d 14, d 28, and d 42 using an Instron Universal Testing Machine (IUTM). Spacing used for IUTM test are as follows: 2 cm for d 14, 4 cm for d 28, 5 cm for d 42. To compare means between data collected for each age of both lines, JMP Pro v. 12 was used though t tests with a significance level (p < 0.05).ResultsBody weight was significantly larger in 2015 RAN line compared to 1995 RAN at ages d 14, d 28, and d 42. Tibia weight was significantly smaller in the 2015 RAN line at d 0 (p = 0.0304), but surpassed the RAN 1995 line at d 14 of age (p = 0.0206). Mean weight was not significantly different between the 2 lines at d 28 and d 42. Mean leg weight to body weight ratio is significantly larger in the 1995 line on d 0 and d 28 (p = 0.0031 and p = 0.0290, respectively), and indicate no significant differences on d 24 or d 42. This trend is also seen in tibia weight to body weight ratio being significantly larger in the 1995 line on d 0 and d 28 (p = 0.0170 and p = 0.0070, respectively). Drum weight to body weight ratio indicate significantly larger ratios for 1995 RAN line on d 0 (p = 0.0008), but this trend does not continue in older ages. Dimensional ratios of tibia proximal width (sagittal) to tibia length (p = 0.0370), tibia distal width (sagittal) to tibial length (p = 0.0118), and tibial midpoint width to tibial length (p = 0.0161) all indicate significantly larger ratios in d 0 1995 RAN compared to d 0 2015 RAN lines, but this trend does not continue in older ages. No differences were detected in the max load, load at break, load extension, and compressive strain force measures.ConclusionInterestingly, many of the parameter reported indicated that at day of hatch, broilers of the 2015 RAN have reduced size associated with the tibia. Allocations of nutrients during embryonic development may be contributing to the discrepancy in birds between the 2 lines at d 0 and can act as a focus in future genetic selections aimed to reduce the incidence of lameness in broilers.

A Univariate Approach to Sex Estimation for the Fragmentary Upper Limb.

Although there are numerous reliable multivariate models for sex estimation, many scenarios, both forensic and archaeological, result in the recovery of fragmentary remains, which prevents the collection of various standard measurements. The purpose of this research was to establish metric applications for sex estimation from the distal humerus and distal radius of European/American Whites and American Blacks. Data for this research were retrieved from a sample consisting of a larger database from multiple skeletal collections. Measurements include epicondylar breadth, breadth of the capitulum-trochlea, and distal breadth of the radius. Student's t-test and descriptive statistics were utilized to analyze the data. Classification rates ranged from 75% to 96.4%, with the capitulum-trochlea breadth performing best. Overall, significant metric differences exist between the sexes in the distal humerus and radius and can be utilized to estimate sex. This study offers a reliable alternative sex estimation technique applicable to fragmentary or damaged remains.

Radiometry versus osteometry in sex assessment: a study of the Cretan radius

Sex estimation is vital for biological profiling, thus qualitative and quantitative methods have been developed for every skeletal part in humans. However, somehow the radius has been neglected. This study aims to develop a sex estimation method on radiographs of the radius applicable in situations when classical osteometry cannot be applied. A total of 103 left radii were used in this study. Three classical measurements (maximum length, head diameter and distal breadth) were taken on the dry bones. Digital radiographs of the same radii were taken using a portable X-ray machine (Technix TCA 4R PLUS). Eight landmarks are selected on the radiograph of the proximal and six on the radiograph of the distal radius, generating in total 43 linear distances. ANOVA detected three osteometric and 24 radiometric variables that differed significantly between males and females (p<0.05). Classical osteometry resulted in up to 91% classification accuracy while the best multivariate formula of the radiometric method gave 88% correct classification. The study proposes a rapid and inexpensive alternative method for sex screening based on digital radiographs of the radius, a method that could be particularly advantageous in cases of mass disasters with numerous mutilated and/or burnt bodies where maceration is not an option.

Effects of Perinatal Circadian Programming on Activity and Skeletal Morphology in C57BL/6 Mice

The timing and duration of locomotor activity can be impacted by changes in environmental light conditions. In mammals, the circadian system in offspring is initially entrained by that of the mother. Photoentrainment of the biological clock by the perinatal light environment begins at birth, and development of the circadian system is completed postnatally when the individual establishes its own internal circadian rhythm. Because of this perinatal to adult patterning, the perinatal light environment can have important developmental consequences to behavior and physiology in the adult. Here we explore the possible effects of photoentrainment on the skeleton using a mouse model system. Skeletal phenotypes are produced through a combination of an animal's genetic background, its plastic responses to its environment (e.g., diet, activity), and the interactions between genetics and environment. Because light environment can have both immediate and long‐term effects on locomotor behavior patterns, variation in photoperiod may impact bone biology indirectly via altered activity levels. To investigate the influence of perinatal light environment on adult activity patterns and bone morphology, one group of C57BL/6 mice was kept under a standard 12:12 L/D photoperiod (12 L; n = 10) and another group (24 L; n = 8) lived under constant light throughout their prenatal and early postnatal development. After five postnatal weeks, the 24 L group were transitioned into a 12:12 photoperiod. Home cage activity data for each animal was collected at 12, 20, and 28 postnatal weeks. After 31 weeks, mice were sacrificed to allow morphometric analyses on dissected long bones. At each of the three time points, we found that the 24 L mice spent significantly less of their time walking (P = 0.044) and walked lower distances overall than the 12 L group (P = 0.006). However, despite significant differences in activity, comparisons of femur length, AP diameter, ML diameter, proximal width, distal width, head height, and head depth indicated no significant differences between the two treatment groups. Overall, our results suggest that while perinatal light environment does have a lasting influence on the activity levels of adults, neither the differences in perinatal environment nor in adult activity between the two treatment groups had a significant impact on femoral morphology. These results support other recent research which has indicated that genetic background has a greater impact on skeletal phenotype than exercise does. Future studies will include investigating bone mineralization and bending mechanics.Support or Funding InformationAmerican Diabetes Association 1‐14‐BS‐181

Subadult sex estimation from diaphyseal dimensions.

Many studies on subadult sex estimation focus on elements that express sexually dimorphic features in adults. In contrast, diaphyseal dimensions have been shown to display sex-specific differences prior to adolescence. The current study evaluates the use of diaphyseal dimensions in subadult sex estimation. Eighteen postcranial measurements from six long bones were collected on Lodox Statscan radiographic images of 1,310 modern South African children between birth and 12 years of age. Linear (LDA) and flexible discriminant analysis (FDA) and logistic regression were employed with single and multiple variable models with age both included and excluded from the model. Bootstrapped cross-validation was employed because some of the multiple variable subsets had small sample sizes. Each of the bootstrapped accuracies has an associated 95% confidence interval demonstrating the ranges in classification. Classification methods utilizing multiple variables achieved the highest bootstrapped classification accuracies (70% to 93%). The inclusion of age in the models did not consistently increase or decrease the classification accuracies. Proximal and distal breadth measurements were consistently recognized as important measurements in model creation. FDA yielded the highest overall accuracies, but the logistic regression presented with overall smaller bootstrapped 95% confidence intervals. Quantifiable sex differences were discovered in the appendicular skeleton of children between birth and 12 years of age. The high classification accuracies were likely due to using numerous predictor variables from multiple skeletal elements, which were optimized for classification using FDA. To facilitate application, a graphical user interface, KidStats, was developed.

Morphometric evaluation of human tendocalcaneus: a cadaveric study of south indian male population.

Tendocalcaneus or Achilles tendon is formed by the fusion of the tendons of gastrocnemius and soleus muscles. Normal morphometric measurements of tendo-calcaneus serves an important landmark in its anthropometric evaluation and biomechanical characteristics. Hence the objective of this study was to provide detailed morphometric profile of tendocalcaneus in south indian cadaveric male population. A total of 64 dissected adult limbs was studied. Out of the 64 limbs: 37 belonged to right side while 27 were of the left side. These limbs were dissected to expose the extent of tendocalcaneus. Total length, proximal width and proximal circumference of the tendon, distal width and distal circumference of the tendon was measured. Results were tabulated and correlated using SPSS. Tendon length, width and circumference showed no statistically significant differences between the right and left side. However significant correlation was observed between proximal width and distal widths, proximal circumference and distal circumference, proximal width and proximal circumference and distal width and distal circumference of the tendon. This cadaveric morphometric study of tendo-calcaneus would be very helpful to sports medicine physicians for diagnosis and treatment of tendo Achilles overuse injuries and tendinopathy. IV.

Comparative analysis of clinical and experimental methods for determination of sexual dimorphism of mandibular canines

The identification of gender is of significance in case of major disasters where bodies are often damaged beyond recognition Teeth are the hardest and chemically the most stable structure in the body. Moreover teeth show signs of least amount of changes in morphology and are easily accessible for examination. Therefore teeth are a first-rate material for genetic and forensic investigations. Out of all the teeth mandibular canines are considered as the “key teeth” for personal identification. Many studies have not been conducted simultaneously intra-orally and on the dental casts to establish the sexual dimorphism in the mandibular canines. The present study was undertaken in north Indian population to check the significance of intraoral measurements - mesio distal width and inter-canine distance as compared with the measurements on the dental casts. The study revealed that both the methods were equally reliable in gender determination.

Assessment of the geometry of proximal femur for short cephalomedullary nail placement: An observational study in dry femora and living subjects.

Background:Intramedullary devices have increasingly become popular and are widely used for fixation of unstable intertrochanteric and subtrochanteric fractures. These implants have been designed taking into consideration of the anthropometry of the western population which varies from those of other ethnic groups. This study was carried out to assess the geometry of proximal femur for the placement of short cephalomedullary nails in our subset of patients and suggest suitable design modifications based on these parameters.Materials and Methods:The study was conducted in the following three groups: (1) Anthropometric study of 101 adult human dry femora, (2) radiographs of the same femora, and (3) radiographs of the contralateral uninjured limb of 102 patients with intertrochanteric or subtrochanteric fractures. In Group 1, standard anthropometric techniques were used to measure neck shaft angle (NSA), minimal neck width (NW), trochanteric offset, and distance from the tip of greater trochanter (GT) to the lower border of lesser trochanter on the femoral shaft axis (distance X). In Group 2 and 3, the NSA, minimal NW, NW at 130° and 135°, trochanteric shaft angle (TSA), trochanteric offset, distance X, distance between the tip of GT and the point where the neck axis crosses the line joining the tip of the GT to the lower border of the lesser trochanter on the femoral shaft axis (distance Y), and canal width at 10, 15, and 20 cm from tip of GT were measured on standard radiographs. The values obtained in these three groups were pooled to obtain mean values. Various parameters of commonly used short cephalomedullary nails available for fixation of pertrochanteric fractures were obtained. These were compared to the results obtained to suggest suitable modifications in the nail designs for our subset of patients.Results:The mean parameters observed were as follows: NSA 128.07° ± 4.97 (range 107°–141°), minimum NW 29.0 ± 2.8 mm (range 22–42 mm), NW at 130° 30.12 ± 2.86 mm (range 22.2–42.5 mm), NW at 135° 30.66 ± 3.02 mm (range 22.8–40.3 mm), TSA 10.45° ± 2.34° (range 3°–15.5°), distance X 65.73 ± 6.45 mm (range 28.6–88.4 mm), distance Y 38 ± 4.91 mm (range 16.6–55.3 mm), and canal width at 10, 15, and 20 cm from the tip of GT 13.46 ± 2.34 mm, 11.40 ± 2.27 mm, and 11.64 ± 2.04 mm, respectively.Conclusion:The measurements of the proximal femur are not significantly different from other ethnic groups and are adequate to accept the current commonly available short cephalomedullary nails. However, certain modifications in the presently available short cephalomedullary nail designs are recommended for them to better fit the anatomy of our subset of population (a) two nails of 125° and 135°, (b) the medio-lateral angle at the level of 65 mm from the tip of the nail, (c) two femoral neck screw placements (35 and 45 mm from the tip of the nail), and (d) five different sizes of distal width for better fit in canal (9–13 mm).

Rediagnosis and redescription of Mosasaurus hoffmannii (Squamata: Mosasauridae) and an assessment of species assigned to the genus Mosasaurus

AbstractThe large Late Cretaceous marine reptile Mosasaurus has remained poorly defined, in part owing to the unorthodox (by today's nomenclatural standards) manner in which the name was erected. The lack of a diagnosis accompanying the first use of either the genus or species names allowed the genus to become a catchall taxon, and subsequent diagnoses did little to refine the concept of Mosasaurus. We herein present emended diagnoses for both Mosasaurus and the type species M. hoffmannii, based solely on personal examination of the holotype, and a description of the type species based on personal examination of many specimens. Mosasaurus exhibits a premaxilla with a short, conical edentulous rostrum, a maxilla with little to no dorsal excavation for the external naris, posteromedial processes of the frontal that deeply invade the parietal, a quadrate taller than long with a short suprastapedial process and the stapedial pit dorsal to the mid-height of the shaft, an angular that is laterally visible for only a short length of the post-dentary unit, a very tall surangular, a humerus with the postglenoid process robust and offset and a distal width greater than the length, and a pubis with an anteriorly projecting tubercle. M. hoffmannii is distinguished from other species assignable to the genus by the anteroventral corner formed on the tympanic rim of the quadrate, the asymmetric carinae of the anterior marginal teeth dividing the tooth circumference into short labial and long lingual segments, and the proximal and distal expansion of the femur.

The Odocoileus virginianus Femur: Mechanical Behavior and Morphology.

Biomechanical research relies heavily on laboratory evaluation and testing with osseous animal structures. While many femora models are currently in use, including those of the European red deer (Cervus elaphus), the Odocoileus virginianus femur remains undocumented, despite its regional abundance in North America. The objective of this study was to compare biomechanical and morphological properties of the Odocoileus virginianus femur with those of the human and commonly used animal models. Sixteen pairs of fresh-frozen cervine femora (10 male, 6 female, aged 2.1 ± 0.9 years) were used for this study. Axial and torsional stiffnesses (whole bone) were calculated following compression and torsion to failure tests (at rates of 0.1 mm/sec and 0.2°/sec). Lengths, angles, femoral head diameter and position, periosteal and endosteal diaphyseal dimensions, and condylar dimensions were measured. The results show that the cervine femur is closer in length, axial and torsional stiffness, torsional strength, and overall morphology to the human femur than many other commonly used animal femora models; additional morphological measurements are comparable to many other species’ femora. The distal bicondylar width of 59.3mm suggests that cervine femora may be excellent models for use in total knee replacement simulations. Furthermore, the cervine femoral head is more ovoid than other commonly-used models for hip research, making it a more suitable model for studies of hip implants. Thus, with further, more application-specific investigations, the cervine femur could be a suitable model for biomechanical research, including the study of ballistic injuries and orthopaedic device development.

A radicle solution: morphology and biomechanics of the Eucalyptocrinites ‘root’ system

Eucalyptocrinites is one the most common and familiar mid-Palaeozoic crinoids and is the exemplar of a form with dendritic radicular holdfasts. American museums have hundreds of specimens of Eucalyptocrinites holdfasts from the Silurian Waldron Shale of Indiana and Kentucky, USA. The radix (‘root’) system of Eucalyptocrinites can be described as comprised of links (branches) that meet at nodes. Measured values include the x- and y-coordinates of the nodes, the distances of the nodes from the stem, the angles between branches, branch length and branch width. Rose diagrams show clearly that the root systems are not isotropic but have preferred orientations. Branch angles are highly variable, but cluster around 60 degrees. Branch lengths and distal branch widths are relatively constant, but branch width increases variably towards the column. The branching pattern can be modelled as a self-similar (‘fractal’) structure. Several specimens labelled as Eucalyptocrinites show a distinct fivefold symmetry without branching and very likely represent a different taxon. The Eucalyptocrinites radix system, along with the probably stiff dististele, most likely functioned as a rigid plate that resisted rotational forces due to currents acting on the crown. Upstream radicles experienced tension, whereas downstream roots were compressed. This force distribution may explain the observed anisotropies in radix morphology. The ‘roots’ of Eucalyptocrinites and other crinoids have long been compared with the root systems of plants. Although there are superficial similarities, there are fundamental differences.

Estimation of stature using fragmentary femur and tibia lengths in a Thai population

Stature estimation is one of the most important parameters for human identification. The current study aimed to investigate the relationship between stature and femur and tibia measurements other than length in modern Thai skeletons, and to derive regression equations that can be used for living stature estimation when complete bones are unavailable. The sample consisted of 159 males and 96 females. We used two analytical methods, i.e. direct 1-step and indirect 2-step. Results showed that the upper breadth of the femur from males and the maximum anteroposterior diameter of the lateral condyle from females were the best estimators of stature. Maximum proximal breadth of the tibia showed the lowest standard error values in males and females. The derived equations were tested on a holdout sample in which the distal breadth of the tibia exhibited the lowest mean absolute error in both males and females, while in the femur measurements, the maximum anteroposterior diameter of the lateral condyle produced the lowest mean absolute error in males, and an absolute mean value from vertical head diameter in females. The present study suggests that measurements taken from damaged bones can be used for stature estimation.

A new species of the hermit crab genusMichelopagurusMcLaughlin, 1997 (Crustacea: Decapoda: Paguridae) from Moorea, French Polynesia

Abstract A new species of the family Paguridae Latreille, 1802, Michelopagurus tangaloa n. sp., is described from deep waters (485–1145 m) off the coast of Moorea, French Polynesia, South Pacific. This new species is the fifth known in the genus Michelopagurus McLaughlin, 1997, and the third from the Indo-West Pacific; the other two species are distributed in the Atlantic Ocean. All five species are rarely collected and most are known from a few type specimens. The new species most closely resembles its Indonesian congener M. chacei McLaughlin, 1997 but can be differentiated by having an acutely triangular rostrum terminating in a small spine, instead of the broadly rounded, terminally unarmed rostrum in M. chacei. Other subtle differences are: corneas reduced, not dilated or wider than distal width of peduncle in M. tangaloa n. sp., whereas corneas are weakly dilated and wider than distal width of peduncle in M. chacei; right cheliped dorsal surface of palm lacking spines, and carpi at most with weak dor...

A new species of Ichthyosaurus from the Lower Jurassic of West Dorset, England, U.K.

ABSTRACTWe describe a new species of Lower Jurassic (Hettangian/Sinemurian–Pliensbachian) ichthyosaur, Ichthyosaurus anningae, sp. nov., from west Dorset, England, U.K. The holotype of I. anningae (DONMG:1983.98), at least a subadult, is from the lower Pliensbachian Stonebarrow Marl Member (Charmouth Mudstone Formation). It is the most complete ichthyosaur known from this time interval worldwide. The species is assigned to Ichthyosaurus on the basis of humerus, forefin, and pectoral girdle morphologies. Diagnostic features of the species include a short, robust humerus with prominent processes; a femur in which the proximal width is almost as large as the distal width; and a very small femur relative to the humerus (humerus/femur ratio >1.7). Four other specimens, at least three of which are juveniles, are referred to this species. The new species may display sexual dimorphism in humeral morphology, but this cannot be confirmed due to a lack of stratigraphic information. With the recognition of I. anningae, at least three and possibly as many as five ichthyosaur species, representing three genera, are known from the Pliensbachian.http://zoobank.org/urn:lsid:zoobank.org:pub:A5778FB5-A116-480A-93CA-AFC932ACAB55SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP