Possible origins and implications of atypical morphologies and domestication-like traits in wild golden jackals (Canis aureus).

Deciphering the origins of phenotypic variations in natural animal populations is a challenging topic for evolutionary and conservation biologists. Atypical morphologies in mammals are usually attributed to interspecific hybridisation or de-novo mutations. Here we report the case of four golden jackals (Canis aureus), that were observed during a camera-trapping wildlife survey in Northern Israel, displaying anomalous morphological traits, such as white patches, an upturned tail, and long thick fur which resemble features of domesticated mammals. Another individual was culled under permit and was genetically and morphologically examined. Paternal and nuclear genetic profiles, as well as geometric morphometric data, identified this individual as a golden jackal rather than a recent dog/wolf-jackal hybrid. Its maternal haplotype suggested past introgression of African wolf (Canis lupaster) mitochondrial DNA, as previously documented in other jackals from Israel. When viewed in the context of the jackal as an overabundant species in Israel, the rural nature of the surveyed area, the abundance of anthropogenic waste, and molecular and morphological findings, the possibility of an individual presenting incipient stages of domestication should also be considered.

Morphologic aspects of the cervical (C3-C7) annular epiphysis: a skeletal study.

BACKGROUND CONTEXT: The annular epiphysis (AE) is a peripheral ring of cortical bone that forms a secondary ossification center in the superior and inferior surfaces of vertebral bodies (VBs). The AE is the last ossification site in the skeleton, typically forming at about the 25th year of life. The AE functions jointly with vertebral endplates to anchor the intervertebral discs to the VBs. PURPOSE: To establish accurate data on the sizes of the AE of the cervical spine (C3-C7); to compare the ratios between areas and the ratios of the AE to VBs; to compare the ratios between the superior and inferior VB surface areas; and to compare AE lengths between the posterior and anterior midsagittal areas. STUDY DESIGN: Measurement of 424 cervical spines (C3-C7) obtained from the skeletal collection of the Natural History Museum, Cleveland, Ohio (USA). METHODS: The sample was characterized by sex, age, and ethnic origin. The following measurements were recorded for each vertebra: (1) the surface area of the VBs and the AE, (2) the midsagittal anterior and posterior length of the AE, (3) the ratios between the AE and VB surface areas, and (4) the ratios between the superior and inferior disc surface areas. RESULTS: The study revealed that the AE and VBs in men were larger than in women. With age, the AE and VBs became larger; the ratio between the AE and VB surface was approximately 0.5 throughout the middle to lower cervical spine. The ratio of superior to inferior VBs was approximately 0.8. We found no differences between African Americans versus European Americans or between the anterior versus the posterior midsagittal length of the AE of the superior and inferior VBs. CONCLUSIONS: The ratios between the superior and inferior VBs are ≥0.8, and the ratio is the same for the entire middle to lower spine. Thus, the ratio between the superior and inferior VBs to the AE is ≥ 0.5. Men had larger AEs and VBs than women did, with both VBs and AEs becoming larger with age. Knowing these relationships are important so that orthopedic surgeons can best correct these issues in young patients (<25 years old) during spine surgery. The data reported here provide, for the first time, all the relevant sizes of the AE and VB. In future studies, AEs and VBs of living patients can be measured with computed tomography. CLINICAL SIGNIFICANCE: The ER location and function are clinically significant showing any changes during life that might lead to clinical issues related to intervertebral discs such as intervertebral disc asymmetry, disc herniation, nerve pressure, cervical osteophytes and neck pain.

On the job training in the dissection room: from physical therapy graduates to junior anatomy instructors.

BACKGROUND:  The training of near-peer (NP) teachers and junior faculty instructors received major attention as a possible solution for the shortage of experienced anatomy instructors in faculties of medicine and health professions. Several studies described the training of NP teachers and junior instructors (≤ 2 years of teaching experience) using various methods. However, few publications include On the Job Training (OJT), which enables reflection and performance evaluation and encourages professionals to cope with their blind spots. Previous publications describing OJT did not include formal observation of the NP teacher or junior instructor. Therefore, this study aimed to present a novel approach to OJT inclusion during prosection laboratories based on the Lewinian experiential model. METHODS:  Eight physical therapy (PT) graduates were recruited as junior anatomy instructors into the prosection laboratories. All participated in a unique training program during two consecutive academic years (2017, 2018) and received OJT during the teaching sessions. Two questionnaires were filled out to evaluate the educational impact of the training program. Eighty-three first-year PT students participated in prosection laboratories in anatomy taught by junior instructors, and filled out a questionnaire evaluating the performance of both junior and senior instructors. In addition, we compared the final grades in anatomy obtained by students taught by senior instructors to the grades of those taught by junior instructors. RESULTS:  Each junior anatomy instructor participated in four OJT sessions. Based on self-reported measures, all professional and didactic aspects of the training program received a median score of 4.5 or higher on a five-point Likert scale. Students obtained similar grades in anatomy when taught by junior instructors compared with senior ones, and were similarly satisfied from the teaching performance of both senior and junior anatomy instructors. CONCLUSIONS:  OJT is applicable in a small-sized PT program facing a shortage of anatomy instructors. Including junior anatomy instructors in prosection laboratories for PT students is a viable solution to the shortage of experienced anatomy instructors. Further study, involving a larger cohort with a longer follow up will strengthen the preliminary results presented here.

The earliest Pleistocene record of a large-bodied hominin from the Levant supports two out-of-Africa dispersal events.

The paucity of early Pleistocene hominin fossils in Eurasia hinders an in-depth discussion on their paleobiology and paleoecology. Here we report on the earliest large-bodied hominin remains from the Levantine corridor: a juvenile vertebra (UB 10749) from the early Pleistocene site of 'Ubeidiya, Israel, discovered during a reanalysis of the faunal remains. UB 10749 is a complete lower lumbar vertebral body, with morphological characteristics consistent with Homo sp. Our analysis indicates that UB-10749 was a 6- to 12-year-old child at death, displaying delayed ossification pattern compared with modern humans. Its predicted adult size is comparable to other early Pleistocene large-bodied hominins from Africa. Paleobiological differences between UB 10749 and other early Eurasian hominins supports at least two distinct out-of-Africa dispersal events. This observation corresponds with variants of lithic traditions (Oldowan; Acheulian) as well as various ecological niches across early Pleistocene sites in Eurasia.

Sexual dimorphism of the posterior cervical spine muscle attachments.

Cervical spinal injury and neck pain are common disorders with wide physical implications. Neck pain and disability are reported to occur in females more often than in males, and chronic or persistent neck pain after whiplash is twice as common in females. Female athletes also sustain a higher percentage of concussions compared to male athletes. Still, while sexual differences in clinical presentation and outcome are well-established, the underlying etiology for the disparity remains less clear. It is well-established that the origin and insertion landmarks of posterior neck muscles are highly variable, but we do not know if these interindividual differences are associated with sex. Expanding our knowledge on sexual dimorphism in the anatomy of the cervical muscles is essential to our understanding of the possible biomechanical differences between the sexes and hence improves our understanding as to why females suffer from cervical pain more than males. It is also of paramount importance for accurate planning of posterior cervical spine surgery, which cuts through the posterior cervical musculature. Therefore, our main objective is to characterize the anatomy of posterior neck musculature and to explore possible sexual differences in the location of their attachment points. Meticulous posterior neck dissection was performed on 35 cadavers, 19 females, and 16 males. In each specimen, 8 muscle groups were examined bilaterally at 45 osseous anatomical landmarks. Muscles and their attachment sites were evaluated manually then photographed and recorded using Microscribe Digitizer technology built into 3D models. A comparison of attachment landmarks between males and females for each muscle was conducted. Out of the eight muscles that were measured, only two muscles demonstrated significant sex-related anatomical differences-Spinotranversales (splenius capitis and cervicis) and Multifidus. Male Spinotransversales muscle has more attachment points than female. It showed more cranial insertion points in the upper cervical attachments (superior nuchal line, C1 posterior tubercle, and mastoid process) and more caudal insertion points in the spinous processes and transverse processes of the lower cervical and upper thoracic vertebrae. Thus, the male subjects in this study exhibited a greater coverage of the posterior neck both cranially and caudally. Female Multifidus has more attachment points on the spinous processes and articular processes at middle and lower cervical vertebrae and at the transverse processes of the upper thoracic vertebrae. All remaining muscles exhibited no sexual differences. Our findings highlight, for the first time, a sexual dimorphism in attachment points of posterior cervical musculature. It reinforces the notion that the female neck is not a scaled version of the male neck. These differences in muscle attachment could partially explain differences in muscle torque production and range of motion and thus biomechanical differences in cervical spine stabilization between sexes. It sheds a much-needed light on the reason for higher whiplash rates, concussion, and chronic cervical pain among females. Surgeons should take these sexual morphological differences into consideration when deliberating the best surgical approach for posterior cervical surgery.

Late subadult ontogeny and adult aging of the human thorax reveals divergent growth trajectories between sexes.

Sexual dimorphism is an important feature of adult thorax morphology, but when and how sex-related differences in the ribcage arise during ontogeny is poorly known. Previous research proposed that sex-related size differences in the nasal region arise during puberty. Therefore, we explore whether ribcage sexual dimorphism also arises at that time and whether this sexual dimorphism is maintained until old age. We measured 526 (semi)landmarks on 80 CT-based human ribcage reconstructions, on individuals ranging from 7 to 65 year-old. The 3D coordinates were submitted to the Procrustes superimposition and analyzed. Our results show that the trajectories of thorax size and shape between sexes diverge at around 12 years of age, and continue slightly diverging until old age. The differential ontogenetic trends cause adult male ribcages to become deeper, shorter, and wider than female. Our results are consistent with the evidence from the cranial respiratory system, with the development of sexual dimorphism probably related to changes in body composition during puberty combined with changes in the reproductive system.

Rib cage anatomy in Homo erectus suggests a recent evolutionary origin of modern human body shape.

The tall and narrow body shape of anatomically modern humans (Homo sapiens) evolved via changes in the thorax, pelvis and limbs. It is debated, however, whether these modifications first evolved together in African Homo erectus, or whether H. erectus had a more primitive body shape that was distinct from both the more ape-like Australopithecus species and H. sapiens. Here we present the first quantitative three-dimensional reconstruction of the thorax of the juvenile H. erectus skeleton, KNM-WT 15000, from Nariokotome, Kenya, along with its estimated adult rib cage, for comparison with H. sapiens and the Kebara 2 Neanderthal. Our three-dimensional reconstruction demonstrates a short, mediolaterally wide and anteroposteriorly deep thorax in KNM-WT 15000 that differs considerably from the much shallower thorax of H. sapiens, pointing to a recent evolutionary origin of fully modern human body shape. The large respiratory capacity of KNM-WT 15000 is compatible with the relatively stocky, more primitive, body shape of H. erectus.

3D geometric morphometric analysis of variation in the human lumbar spine.

OBJECTIVES: The shape of the human lumbar spine is considered to be a consequence of erect posture. In addition, several other factors such as sexual dimorphism and variation in genetic backgrounds also influence lumbar vertebral morphology. Here we use 3D geometric morphometrics (GM) to analyze the 3D morphology of the lumbar spine in different human populations, exploring those potential causes of variation. MATERIAL AND METHODS: We collected 390 (semi) landmarks from 3D models of the CT scans of lumbar spines of seven males and nine females from a Mediterranean population (Spain, Israel) and seven males and either females from a South African population for geometric morphometric (GM) analysis. We carried out Generalized Procrustes Analysis, Principal Components, and Regression analyses to evaluate shape variation; and complemented these analyses with the Cobb Method. RESULTS: The Mediterranean sample was considerably more lordotic than the South African sample. In both populations, female lumbar spines showed proportionally narrower and more craniocaudally elongated lumbar segments than in males. In addition, the point of maximum curvature in females tended to be located more inferiorly than in males. DISCUSSION: Our results show that sexual dimorphism is an important factor of lumbar spine variation that mainly affects features of lumbar spine robustness (height proportions) and the structure-but not the degree-of its curvature. Differences in lordosis, however, are clearer at the inter-population level. This reflects previous conflicting studies casting doubts on pregnancy as an adaptive factor influencing lordosis. Other factors, for example, shape of the individual lumbar vertebrae and intervertebral discs and their relative proportions within the lumbar spine should be considered when exploring variation in vertebral column morphology.

3D virtual reconstruction of the Kebara 2 Neandertal thorax.

The size and shape of the Neandertal thorax has been debated since the first discovery of Neandertal ribs more than 150 years ago, with workers proposing different interpretations ranging from a Neandertal thoracic morphology that is indistinguishable from modern humans, to one that was significantly different from them. Here, we provide a virtual 3D reconstruction of the thorax of the adult male Kebara 2 Neandertal. Our analyses reveal that the Kebara 2 thorax is significantly different but not larger from that of modern humans, wider in its lower segment, which parallels his wide bi-iliac breadth, and with a more invaginated vertebral column. Kinematic analyses show that rib cages that are wider in their lower segment produce greater overall size increments (respiratory capacity) during inspiration. We hypothesize that Neandertals may have had a subtle, but somewhat different breathing mechanism compared to modern humans.

The torso integration hypothesis revisited in Homo sapiens: Contributions to the understanding of hominin body shape evolution.

OBJECTIVES: Lower thoracic widths and curvatures track upper pelvic widths and iliac blades curvatures in hominins and other primates (torso integration hypothesis). However, recent studies suggest that sexual dimorphism could challenge this assumption in Homo sapiens. We test the torso integration hypothesis in two modern human populations, both considering and excluding the effect of sexual dimorphism. We further assess covariation patterns between different thoracic and pelvic levels, and we explore the allometric effects on torso shape variation. MATERIAL AND METHODS: A sex-balanced sample of 50 anatomically connected torsos (25 Mediterraneans, 25 Sub-Saharan Africans) was segmented from computed tomography scans. We compared the maximum medio-lateral width at seventh-ninth rib levels with pelvic bi-iliac breadth in males and females within both populations. We measured 1,030 (semi)landmarks on 3D torso models, and torso shape variation, mean size and shape comparisons, thoraco-pelvic covariation and allometric effects were quantified through 3D geometric morphometrics. RESULTS: Females show narrow thoraces and wide pelves and males show wide thoraces and narrow pelves, although this trend is more evident in Mediterraneans than in Sub-Saharans. Equal thoracic and pelvic widths, depths and curvatures were found in absence of sexual dimorphism. The highest strength of covariation was found between the lowest rib levels and the ilia, and allometric analyses showed that smaller torsos were wider than larger torsos. CONCLUSIONS: This is the first study testing statistically the torso integration hypothesis in anatomically connected torsos. We propose a new and more complex torso integration model in H. sapiens with sexual dimorphism leading to different thoracic and pelvic widths and curvatures. These findings have important implications in hominin body shape reconstructions.

Students as anatomy near-peer teachers: a double-edged sword for an ancient skill.

BACKGROUND: A near-peer instructors (NPI) program was designed for 1st year medical students who successfully finished the Anatomy course, in order to develop their didactic ability and teaching skills, mostly for cadaver dissection. METHODS: Graduates of the training program were administered a voluntary survey at the end of the program, annually. Best graduates of the training program were offered a NPI position in the next academic year. They were evaluated by the first-year students, at the end of the Anatomy block. RESULTS: In a debriefing questionnaire at the end of the NPI training, on the five-point Likert scale (1 = lowest to 5 = highest), the overall rating ranged from 3.63 in 2013 to 3.71 in 2015. Learning prosection and anatomy demonstration skills scored on average from 4.30 to 4.36, respectively. The NPIs were then evaluated by first-year students at the end of the next year's Anatomy block. On the Likert scale, the average score of NPIs ranged from 4.10 in 2014 to 4.75 in 2016, on the par with the general satisfaction score for the professional preclinical teachers during the same period (which ranged from 3.80 to 4.26). CONCLUSIONS: It is suggested that students as near-peer instructors can make a valuable contribution to the teaching faculty, especially in a new medical school.

Three-dimensional morphometrics of thoracic vertebrae in Neandertals and the fossil evidence from El Sidrón (Asturias, Northern Spain).

Well preserved thoracic vertebrae of Neandertals are rare. However, such fossils are important as their three-dimensional (3D) spatial configuration can contribute to the understanding of the size and shape of the thoracic spine and the entire thorax. This is because the vertebral body and transverse processes provide the articulation and attachment sites for the ribs. Dorsal orientation of the transverse processes relative to the vertebral body also rotates the attached ribs in a way that could affect thorax width. Previous research indicates possible evidence for greater dorsal orientation of the transverse processes and small vertebral body heights in Neandertals, but their 3D vertebral structure has not yet been addressed. Here we present 15 new vertebral remains from the El Sidrón Neandertals (Asturias, Northern Spain) and used 3D geometric morphometrics to address the above issues by comparing two particularly well preserved El Sidrón remains (SD-1619, SD-1641) with thoracic vertebrae from other Neandertals and a sample of anatomically modern humans. Centroid sizes of El Sidrón vertebrae are within the human range. Neandertals have larger T1 and probably also T2. The El Sidrón vertebrae are similar in 3D shape to those of other Neandertals, which differ from Homo sapiens particularly in central-lower regions (T6-T10) of the thoracic spine. Differences include more dorsally and cranially oriented transverse processes, less caudally oriented spinous processes, and vertebral bodies that are anteroposteriorly and craniocaudally short. The results fit with current reconstructions of Neandertal thorax morphology.

The first Neanderthal remains from an open-air Middle Palaeolithic site in the Levant.

The late Middle Palaeolithic (MP) settlement patterns in the Levant included the repeated use of caves and open landscape sites. The fossil record shows that two types of hominins occupied the region during this period-Neandertals and Homo sapiens. Until recently, diagnostic fossil remains were found only at cave sites. Because the two populations in this region left similar material cultural remains, it was impossible to attribute any open-air site to either species. In this study, we present newly discovered fossil remains from intact archaeological layers of the open-air site 'Ein Qashish, in northern Israel. The hominin remains represent three individuals: EQH1, a nondiagnostic skull fragment; EQH2, an upper right third molar (RM3); and EQH3, lower limb bones of a young Neandertal male. EQH2 and EQH3 constitute the first diagnostic anatomical remains of Neandertals at an open-air site in the Levant. The optically stimulated luminescence ages suggest that Neandertals repeatedly visited 'Ein Qashish between 70 and 60 ka. The discovery of Neandertals at open-air sites during the late MP reinforces the view that Neandertals were a resilient population in the Levant shortly before Upper Palaeolithic Homo sapiens populated the region.

The Neandertal vertebral column 2: The lumbar spine.

Here we provide the most extensive metric and morphological analysis performed to date on the Neandertal lumbar spine. Neandertal lumbar vertebrae show differences from modern humans in both the vertebral body and in the neural arch, although not all Neandertal lumbar vertebrae differ from modern humans in the same way. Differences in the vertebral foramen are restricted to the lowermost lumbar vertebrae (L4 and L5), differences in the orientation of the upper articular facets appear in the uppermost lumbar vertebrae (probably in L1 and L2-L3), and differences in the horizontal angle of the transverse process appear in L2-L4. Neandertals, when compared to modern humans, show a smaller degree of lumbar lordosis. Based on a still limited fossil sample, early hominins (australopiths and Homo erectus) had a lumbar lordosis that was similar to but below the mean of modern humans. Here, we hypothesize that from this ancestral degree of lumbar lordosis, the Neandertal lineage decreased their lumbar lordosis and Homo sapiens slightly increased theirs. From a postural point of view, the lower degree of lordosis is related to a more vertical position of the sacrum, which is also positioned more ventrally with respect to the dorsal end of the pelvis. This results in a spino-pelvic alignment that, though different from modern humans, maintained an economic postural equilibrium. Some features, such as a lower degree of lumbar lordosis, were already present in the middle Pleistocene populations ancestral to Neandertals. However, these middle Pleistocene populations do not show the full suite of Neandertal lumbar morphologies, which probably means that the characteristic features of the Neandertal lumbar spine did not arise all at once.

Evolution of Spinopelvic Alignment in Hominins.

Spinopelvic alignment refers to the interaction between pelvic orientation, spinal curvatures, and the line of gravity. In a healthy modern human, this alignment is characterized by reciprocal curves/orientation of the sacrum, lumbar lordosis, thoracic kyphosis, and cervical lordosis. In an economic sagittal posture, these curvatures keep the line of gravity close to the center of the acetabulum. The purpose of this study is to explore the spinopelvic alignment in extinct hominins. We examined spinopelvic alignment of a single representative from each of the following hominin groups: Australopithecus, Homo erectus (H. erectus), H. neanderthalensis, and early H. sapiens. Pelvic incidence, lumbar lordosis, thoracic kyphosis, and cervical lordosis for each representative was estimated and compared with that of modern humans. Three basic spinopelvic alignments were found: (1) the sinusoidal alignment with moderate to high spinal curvatures and pelvic incidence found in H. erectus and H. sapiens; (2) the straight alignment with small spinal curvatures and small pelvic incidence found in Neandertal lineage hominins; (3) the compound alignment found in Australopithecus, with moderate pelvic incidence and lumbar lordosis, and nearly straight cervical spine. Our results indicate that balanced upright posture can be achieved in different alignments. Each hominin group solved the requirements of erect posture in a slightly different way. Moreover, we propose the term "cranio-spino-pelvic balance" to substitute "spino-pelvic balance." From an evolutionary perspective, not only changes in the pelvis have conditioned the evolution of the spinal curvatures but also changes in the equilibrium of the head likely also affected this balance. Anat Rec, 300:900-911, 2017. © 2017 Wiley Periodicals, Inc.

Monumental megalithic burial and rock art tell a new story about the Levant Intermediate Bronze "Dark Ages".

The Intermediate Bronze Age (IB) in the Southern Levant (ca. 2350-2000 BCE) is known as the "Dark Ages," following the collapse of Early Bronze urban society and predating the establishment of the Middle Bronze cities. The absence of significant settlements and monumental building has led to the reconstruction of IB social organization as that of nomadic, tribal society inhabiting rural villages with no central governmental system. Excavation in the Shamir Dolmen Field (comprising over 400 dolmens) on the western foothills of the Golan Heights was carried out following the discovery of rock art engravings on the ceiling of the central chamber inside one of the largest dolmens ever recorded in the Levant. Excavation of this multi-chambered dolmen, covered by a basalt capstone weighing some 50 tons, revealed a secondary multi-burial (of both adults and children) rarely described in a dolmen context in the Golan. Engraved into the rock ceiling above the multi-burial is a panel of 14 forms composed of a vertical line and downturned arc motif. 3D-scanning by structured-light technology was used to sharpen the forms and revealed the technique employed to create them. Building of the Shamir dolmens required a tremendous amount of labor, architectural mastery, and complex socio-economic organization well beyond the capacity of small, rural nomadic groups. The monumental megalithic burial of the Shamir dolmens indicates a hierarchical, complex, non-urban governmental system. This new evidence supports a growing body of recent criticism stemming from new discoveries and approaches that calls for rethinking our views of the Levantine IB "Dark Ages."

The relevance of the first ribs of the El Sidrón site (Asturias, Spain) for the understanding of the Neandertal thorax.

Reconstructing the morphology of the Neanderthal rib cage not only provides information about the general evolution of human body shape but also aids understanding of functional anatomy and energetics. Despite this paleobiological importance there is still debate about the nature and extent of variations in the size and shape of the Neandertal thorax. The El Sidrón Neandertals can be used to contribute to this debate, providing new costal remains ranging from fully preserved and undistorted ribs to highly fragmented elements. Six first ribs are particularly well preserved and offer the opportunity to analyze thorax morphology in Neandertals. The aims of this paper are to present this new material, to compare the ontogenetic trajectories of the first ribs between Neandertals and modern humans, and, using geometric morphometrics, to test the hypothesis of morphological integration between the first rib and overall thorax morphology. The first ribs of the El Sidrón adult Neandertals are smaller in centroid size and tend to be less curved when compared with those of modern humans, but are similar to Kebara 2. Our results further show that the straightening of the first ribs is significantly correlated with a straightening of the ribs of the upper thorax (R = 0.66; p < 0.0001) in modern humans, suggesting modularity in the upper and lower thorax units as reported in other hominins. It also supports the hypothesis that the upper thorax of Neandertals differs in shape from modern humans with more anteriorly projecting upper ribs during inspiration. These differences could have biomechanical consequences and account for stronger muscle attachments in Neandertals. Different upper thorax shape would also imply a different spatial arrangement of the shoulder girdle and articulation with the humerus (torsion) and its connection to the upper thorax. Future research should address these inferences in the context of Neandertal overall body morphology.