Anatomy, histology and elemental profile of long bones and ribs of the Asian elephant (Elephas maximus)

How compactness affects long bone resistance to compression-An investigation into the rhinoceros humerus

The functional signal of bone internal structure has been widely studied. Isolated form-function relationships have often been assumed from the observation of presumed morphofunctional relationships, but have never been truly tested. Indeed, distinct bone microanatomical feature co-evolve in response to various constraints that are difficult to detangle. This study tested for the first time the impact of various microanatomical parameters taken one by one, plus some in pairs, on bone strength under compression using biomechanical modelling. We carried out finite element analyses on humerus models, obtained from a white rhinoceros, with different heterogeneous internal structures, and analysed the magnitude and distribution of von Mises stresses. These tests validated earlier hypotheses of form-function relationships about the greater resistance to compression provided by the thickening of the cortex and the filling of the medullary area by trabecular bone and highlighted the stronger impact of increasing trabecular bone compactness than of avoiding an open medullary cavity. By making it possible to estimate the relative impact of each parameter and of combinations of microanatomical features, they also showed the more limited impact of the trabecular bone compactness in the epiphyses to resist compression, and the fact that microanatomical changes of opposite but of similar amplitude impact can compensate each other, but that the impact of the sum of two negative microanatomical changes far exceeds the sum of the impacts of each of the two changes taken separately. These results contribute to a better understanding of bone adaptation and form-function relationships so that they later can be used with confidence for palaeobiological inferences on fossil specimens, contributing to a better understanding of skeletal evolution during the evolutionary history of vertebrates. They also highlight the potential of taking internal structure into account in the bone biomechanical analyses. In addition, they can be used in bioinspiration to design resistant structures subjected to compression.

3D Reconstruction of the Blood Supply in an Elephant's Forefoot Using Fused CT and MRI Sequences

Being the largest still-living terrestrial mammal on earth, an elephant's feet play an important role in its health status. The musculoskeletal structures in the forefoot are well described in the literature, but information about vascularization is limited. The novel aim of this work is to provide anatomical guidance to structures found in the forefoot, focusing on the arterial system. Initially, native CT and MRI sequences were taken of the left forefoot of a deceased 6-year-old female Asian elephant; the foot was then filled with an iodine-containing contrast medium through the a. mediana and the CT scans were repeated in the same position. The images obtained were processed with 3D Slicer software for the 3D reconstruction of the bones and arteries. The results clearly showed the palmar blood supply of the forefoot. A so far undescribed vessel was revealed, stemming from the a. metacarpea, supplying the first digit and the digital cushion. The course of the deep palmar arch's terminal section was also established. This paper provides the first description of the exact disposition of the arteries in the palmar aspect of an elephant's forefoot and may be used in planning surgeries in clinically affected animals.

CT anatomy of cervical vertebrae of Asian elephant ( Elephas maximus )

Background

Elephants are currently the largest mammals on earth. A comprehensive examination of the anatomy of this animal to diagnose various disorders is required. In addition, due to the heavy head of these animals, adaptations have been made in the anatomical structure of the neck that is worth studying.

Objective

This study aimed to investigate a standard morphologic and morphometric description of the elephant cervical spine. Another aim of this study was to compare the changes in the cervical skeleton of elephants with horses and cattle.

Methods

For this study, the cervical vertebrae of the Asian elephant, cattle and horse were examined. CT Images were obtained using Somatom Spirit II CT Machine. Statistical analysis was done by SPSS 24 software.

Results

Two dorsal tubercles and a groove between them were observed on the dorsal arch of the atlas vertebra of the Asian elephant. In elephant samples, the variation of vertebral body height, spinous process height, transverse process width, vertebral body length and vertebral foramen volume indices were statistically significant. The volume of the vertebral foramen in the elephant decreases in the second vertebra compared to the first vertebra, decreases in the third vertebra, decreases in the fourth, increases in the fifth, decreases in the sixth and increases in the seventh.

Conclusions

In this study, the structure of the cervical vertebrae of the Asian elephant was examined, and certain features were observed. One of the main features was the reduction of the length of the vertebrae, which leads to the decrease of the ratio of neck length to the size of the body. This condition can be due to the high weight of the head in the elephant. To maintain this weight, it is necessary to reduce the length of the neck and confer less mobility.

Organic residue analysis reveals the function of bronze age metal daggers

The article discusses results of organic residue analysis performed on ten copper-alloy daggers from Bronze Age Pragatto, Italy, c.1550–1250 BCE. Metal daggers are widespread in Chalcolithic and Bronze Age Europe, yet their social and practical roles are still hotly debated. Are they symbolic or functional? Are they tools or weapons? How were they used? For what tasks and on what materials? The research addresses these questions through a novel application of biochemical staining and SEM–EDX analysis. The method has proved successful in extracting and identifying animal residues located on cutting edges including bone, muscle, and tendons. These are interpreted as evidence of prehistoric carcass butchering and carving. Further residues were observed on blade faces and hafting plates or tangs; these are interpreted as remnants of bone handles and sheaths, the latter made of either wood fibers or processed hide and fur. The readings proposed in the article are validated by original experiments with replica daggers, as detailed in the Supplementary Materials. The analysis and experiments shed new light on Bronze Age metal daggers, showing that they were fully functional tools (and perhaps tool-weapons) primarily utilized for the processing of animal carcasses. This original research result contributes significant knowledge towards interpreting an under-studied, yet socially salient, prehistoric metal artifact.

Function, life histories, and biographies of Lower Paleolithic patinated flint tools from Late Acheulian Revadim, Israel

Flint tools exhibiting modified patinated surfaces ("double patina", or post-patination flaked items) provide a glimpse into Paleolithic lithic recycling, stone economy, and human choices. Different life cycles of such items are visually evident by the presence of fresh new modified surfaces alongside old patinated ones (according to color and texture differences). New modifications testify to a gap in time between the previous life cycle of the patinated flaked item and its new one. The aim of the current study is to reconstruct the functional properties and life cycles of a sample of modified patinated flaked tools from Late Acheulian Revadim, Israel by applying use-wear and residue analyses. The results of the functional study allow a better understanding of the practical reasoning behind the collection and recycling of old flint tools, while additional inputs from theoretical and methodological advancements assist in reconstructing their probable role in the worldviews of the site's inhabitants.

Elemental Distribution in Animal Carpal and Tarsal Bones Using Differences in X-ray Fluorescence Energy

Little is known as to whether different operating voltages of X-ray fluorescence (XRF) can affect the accuracy rate for species identification. Here, we have addressed this question by comparing the rate of correct species identification using the elemental composition of either the carpal or tarsal bone obtained from a determination of the different energy values of XRF at 15 and 50 kV using energy-dispersive XRF (ED-XRF). Carpal bones were taken from 16 species and tarsal bones from 11 of these species. The data on the elemental profiles were analyzed by stepwise discriminant analysis for species discrimination. The classification results indicated that 94.1% and 63.7% of the originally grouped cases were correctly classified as carpal bones using 15 kV and 50 kV, respectively. Additionally, 69.4% and 77.3% of the originally grouped cases were correctly classified as tarsal bones using 15 kV and 50 kV, respectively. When the datasets of the elemental profiles obtained using two operating voltages were gathered, the classification results of the prediction rate appeared to be more accurate at 89.7% and 90.7% in the carpal and tarsal bones, respectively. In conclusion, our findings suggest that the elemental profiles of bones obtained using two operating voltages could effectively facilitate accurate species discrimination.

An integrated study discloses chopping tools use from Late Acheulean Revadim (Israel)

Chopping tools/choppers provide one of the earliest and most persistent examples of stone tools produced and used by early humans. These artifacts appeared for the first time ~2.5 million years ago in Africa and are characteristic of the Oldowan and Acheulean cultural complexes throughout the Old World. Chopping tools were manufactured and used by early humans for more than two million years regardless of differences in geography, climate, resource availability, or major transformations in human cultural and biological evolution. Despite their widespread distribution through time and space in Africa and Eurasia, little attention has been paid to the function of these items, while scholars still debate whether they are tools or cores. In this paper, we wish to draw attention to these prominent and ubiquitous early lithic artifacts through the investigation of 53 chopping tools retrieved from a specific context at Late Acheulean Revadim (Israel). We combined typo-technological and functional studies with a residue analysis aimed at shedding light on their functional role within the tool-kits of the inhabitants of the site. Here we show that most of the chopping tools were used to chop hard and medium materials, such as bone, most probably for marrow extraction. A few of the tools were also used for cutting and scraping activities, while some also served as cores for further flake detachment. The chopping tools exhibit extraordinarily well-preserved bone residues suggesting they were used mainly for bone-breaking and marrow acquisition. We discuss the data and explore the tool versus core debate also in light of a sample of 50 flake cores made on pebbles/cobbles retrieved from the same archeological layer. The results add further pieces to the puzzle of activities carried out at Revadim and add to our knowledge of the production and use of these enigmatic tools and their role in human evolutionary history.

Histology of 24 organs from Asian elephant calves (Elephas maximus)

Background

Elephants are the largest and heaviest living terrestrial animals, but information on their histology is still lacking. This study provides a unique insight into the elephant's organs and also provides a comparison between juvenile Asian elephants and adult Asian elephants or other species. Here we report on the histological structure of 24 organs, including the skin, brain (cerebrum, cerebellar hemisphere, vermis, thalamus, midbrain), spinal cord, sciatic nerve, striated skeletal muscle, cardiac muscle, bone (flat bone and long bone), cartilage (hyaline cartilage and fibrocartilage), heart (right atrium, right ventricle), blood vessels (aorta, pulmonary artery and caudal vena cava), trunk, trachea, lung, tongue, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum), liver and pancreas, kidney, ovary, uterus (body and horn) and spleen of two juvenile Asian elephants.

Methods

Tissue sections were stained with Harris's hematoxylin and eosin Y.

Results

While almost all structures were similar to those of other species or adult elephants, some structures were different from other mammalian species, such as: plexiform bone was found in flat bone only; a thin trachealismuscle was observed in the trachea; and no serous or mucinous glands were found in the submucosa of the trachea.

Discussion

Histological information from various organs can serve as an important foundation of basal data for future microanatomical studies, and help in the diagnosis and pathogenesis in sick elephants or those with an unknown cause of death.

Secondary osteons scale allometrically in mammalian humerus and femur

Intra-cortical bone remodelling is a cell-driven process that replaces existing bone tissue with new bone tissue in the bone cortex, leaving behind histological features called secondary osteons. While the scaling of bone dimensions on a macroscopic scale is well known, less is known about how the spatial dimensions of secondary osteons vary in relation to the adult body size of the species. We measured the cross-sectional area of individual intact secondary osteons and their central Haversian canals in transverse sections from 40 stylopodal bones of 39 mammalian species (body mass 0.3-21 000 kg). Scaling analysis of our data shows that mean osteonal resorption area (negative allometry, exponent 0.23,R² 0.54,p<0.005) and Haversian canal area (negative allometry, exponent 0.31,R² 0.45,p<0.005) are significantly related to body mass, independent of phylogeny. This study is the most comprehensive of its kind to date, and allows us to describe overall trends in the scaling behaviour of secondary osteon dimensions, supporting the inference that the osteonal resorption area may be limited by the need to avoid fracture in smaller mammalian species, but the need to maintain osteocyte viability in larger mammalian species.