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The Mississippian (Lower Carboniferous) succession of Derbyshire contains numerous crinoid specimens, but they remain poorly documented. Although these well-lithified limestones may include abundant crinoids, they are difficult to study; better results can be obtained from weakly lithified mudrocks, as seen elsewhere. A moderately long pluricolumnal of 29 columnals has been collected from the mudrock of the Newton Grange crinoid bed of the Hopedale Limestone Formation, Peak Limestone Group; it most likely comes from high in the formation (=Brigantian) and was deposited in the deeper water of the Widmerpool Gulf. The pluricolumnal is part of the mesistele of either a cladid or a camerate crinoid. The pluricolumnal was originally circular in section, but has been deformed into an ellipse. A second elongate structure, probably a second pluricolumnal (not preserved), was adpressed into the surface, and calcite of the endoskeleton lost on this and the opposite side of the pluricolumnal to expose the axial canal. All these post-burial modifications were probably under the influence of the weight of overburden, but indicate a complex scenario for the preservation of a simple specimen.

Megasecoptera is an extinct group of insects with specialized rostrum-like mouthparts, which is a synapomorphy shared with all members of the Late Paleozoic Palaeodictyopterida, and markedly slender wings that are unable to flex backwards. Here we describe the close up morphology of Protohymenidae and Scytohymenidae and uncover new aspects of the endoskeleton (tentorium) of the head, structure of the mouthparts with discernible proximal part of stylets controlled by muscles, surface of compound eyes that consist of a hexagonal pattern of large facets, structure and microstructures on the wings and reconstruct male and female external genitalia using ESEM and light stereomicroscopy. Furthermore, we describe Protohymen novokshonovi sp. n. based on an exceptionally well preserved fossil from the early Permian at Tshekarda in Russia, which shows crucial details, and the earliest species of Protohymenidae, Carbohymen testai gen. et sp. n. from a late Carboniferous siderite nodule at Mazon Creek in Illinois, USA. Our comparative study confirmed a set of structural and microstructural details on their wings, such as the composite anterior wing margin, development of an apical cell and the previously unknown external genitalia. Based on the results and comparison of homologous structures known primarily for extant relatives, such as mayflies and dragonflies, we outline for the first time the function of the mouthparts, in particular, the stylets, structure of the tentorium, vision provided by large hexagonal ommatidia and male copulatory structures bearing curved claspers for holding a female during copulation and penial lobes with seminal grooves.

The body wall of starfish is composed of magnesium calcite ossicles connected by collagenous tissue and muscles and it exhibits remarkable variability in stiffness, which is attributed to the mechanical mutability of the collagenous component. Using the common European starfish Asterias rubens as an experimental animal, here we have employed a variety of techniques to gain new insights into the structure of the starfish body wall. The structure and organisation of muscular and collagenous components of the body wall were analysed using trichrome staining. The muscle system comprises interossicular muscles as well as muscle strands that connect ossicles with the circular muscle layer of the coelomic lining. The collagenous tissue surrounding the ossicle network contains collagen fibres that form loop‐shaped straps that wrap around calcite struts near to the surface of ossicles. The 3D architecture of the calcareous endoskeleton was visualised for the first time using X‐ray microtomography, revealing the shapes and interactions of different ossicle types. Furthermore, analysis of the anatomical organisation of the ossicles indicates how changes in body shape may be achieved by local contraction/relaxation of interossicular muscles. Scanning synchrotron small‐angle X‐ray diffraction (SAXD) scans of the starfish aboral body wall and ambulacrum were used to study the collagenous tissue component at the fibrillar level. Collagen fibrils in aboral body wall were found to exhibit variable degrees of alignment, with high levels of alignment probably corresponding to regions where collagenous tissue is under tension. Collagen fibrils in the ambulacrum had a uniformly low degree of orientation, attributed to macrocrimp of the fibrils and the presence of slanted as well as horizontal fibrils connecting antimeric ambulacral ossicles. Body wall collagen fibril D‐period lengths were similar to previously reported mammalian D‐periods, but were significantly different between the aboral and ambulacral samples. The overlap/D‐period length ratio within fibrils was higher than reported for mammalian tissues. Collectively, the data reported here provide new insights into the anatomy of the body wall in A. rubens and a foundation for further studies investigating the structural basis of the mechanical properties of echinoderm body wall tissue composites.

A new larger benthic foraminifera is described as Banatia aninensis n. gen., n. sp. (Family Pfenderinidae Smout & Sugden) from upper Barremian Urgonian-type shallow-water carbonates of the Resita – Moldova Noua Zone, southwestern part of Romania. The low to medium trochospiral test of Banatia n. gen. is characterized by marginally undivided chambers and a wide axial part. The latter is made up of pillars continuous between successive chambers and a labyrinthic endoskeleton (plates and pillars) with a fine canal system between. Banatia n. gen. is compared with Pfenderina Henson, Pseudopfenderina Hottinger, and Accordiella Farinacci. The new taxon occurs in algal-foraminiferal wackestones interpreted as deposits of an internal lagoonal realm. So far unrecorded in the literature, the taxon might be paleogeographically restricted (endemic).

Infection of the hip after implant fixation is an uncommon yet devastating complication that results in poor long-term outcome. The gold standard treatment for chronic infection after hip arthroplasty is a two-stage protocol: eradication of infection, follow by re-implantation arthroplasty. The use of interim antibiotic-laden cement spacer has become a popular procedure to maintain hip joint function and provide antibiotic elution simultaneously before re-implantation. However, antibiotic cement spacer is mechanically weak and breaks if overloaded. Therefore, we designed a cement mould with metallic endoskeleton with the aim of creating a stronger, inexpensive, antibiotic-impregnated spacer resembling a unipolar arthroplasty. We report two cases of severe hip joint infection after implant fixation (bipolar hemiarthroplasty, screw fixation neck of femur). Both patients had undergone first stage surgery of debridement and articulating antibiotic cement insertion using our design. Although the second stage surgery was planned for these patients, both patients delayed the operation in view of good functional status after a year walking with the antibiotic cement spacer. These cases showed that the mechanical property of the new antibiotic cement spacer was promising but further mechanical studies upon this new endoskeleton design are required.

Pulse wave velocity (PWV), which measures vascular stiffness, is a powerful predictor of cardiovascular event. Treatment of aneurysms with endovascular prosthesis has been reported to increase PWV. The purpose of this study was to evaluate whether an endoskeleton stent graft design has less effect on PWV than the exoskeleton stent graft design. Between July 2008 and September 2016, 74 patients underwent endovascular treatment of aortic arch aneurysm in our institution. PWV before and after surgery were compared between those who underwent treatment with Najuta, an endoskeleton stent graft (n = 51), and those treated with other commercially available exoskeleton stent grafts (n = 23). Preoperative PWV (endoskeleton: 2004 ± 379.2 cm/s vs. exoskeleton: 2083 ± 454.5 cm/s, p = 0.47) was similar between the two groups. Factors that were associated with preoperative PWV were age (r = 0.37, 95% CI 0.15–0.56, p = 0.002) and mean arterial pressure (r = 0.53, 95% CI 0.34–0.68, p

Ninety per cent of animals do not have a spine. In the adult state it exists only in chordates. Among them, only vertebrates (0.8% of the biomass) have a cartilaginous or osseous endoskeleton with this type of axial structure around which the symmetry of the body is organized. It is involved in the maintenance of posture and locomotion. In most aquatic vertebrates the spinal column alone provides most of these functions. In terrestrial vertebrates, from amphibians to primates, the limbs assume a role in movement. Its coupling with the limbs, thanks to the pelvis, allows it to play an essential role in the postural balance and movements in vertebrates.

International audience; The monobasal pectoral fins of living coelacanths and lungfishes are homologous to the forelimbs of tetrapods and are thus critical to investigate the origin thereof. However, it remains unclear whether the similarity in the asymmetrical endoskeletal arrangement of the pectoral fins of coelacanths reflects the evolution of the pectoral appendages in sarcopterygians. Here, we describe for the first time the development of the pectoral fin and shoulder girdle in the extant coelacanth Latimeria chalumnae, based on the tomographic acquisition of a growth series. The pectoral girdle and pectoral fin endoskeleton are formed early in development with a radially outward growth of the endoskeletal elements. The visualization of the pectoral girdle during development shows a reorientation of the girdle between the fetus and pup 1 stages, creating a contact between the scapulocoracoids and the clavicles in the ventro‐medial region. Moreover, we observed a splitting of the pre‐ and post‐axial cartilaginous plates in respectively pre‐axial radials and accessory elements on one hand, and in post‐axial accessory elements on the other hand. However, the mechanisms involved in the splitting of the cartilaginous plates appear different from those involved in the formation of radials in actinopterygians. Our results show a proportional reduction of the proximal pre‐axial radial of the fin, rendering the external morphology of the fin more lobe‐shaped, and a spatial reorganization of elements resulting from the fragmentation of the two cartilaginous plates. Latimeria development hence supports previous interpretations of the asymmetrical pectoral fin skeleton as being plesiomorphic for coelacanths and sarcopterygians.

Many vertebrates are armored over all or part of their body. The armor may serve several functional roles including defense, offense, visual display, and signal of experience/capability. Different roles imply different tradeoffs; for example, defensive armor usually trades resistance to attack for maneuverability. The poachers (Agonidae), 47 species of scorpaeniform fishes, are a useful system for understanding the evolution and function of armor due to their variety and extent of armoring. Using publically available CT-scan data from 27 species in 16 of 21 genera of poachers we compared the armor to axial skeletal in the mid body region. The ratio of average armor density to average skeleton density ranged from 0.77 to 1.17. From a defensive point of view, the total investment in mineralization (volume * average density) is more interesting. There was 10 times the material invested in the armor as in the endoskeleton in some small, smooth plated species, like Aspidophoroides olrikii. At the low end, some visually arresting species like Percis japonica, had ratios as low as 2:1. We categorized the extent and type (impact vs. abrasion) in 34 Agonopsis vulsa across all 35+ plates in the eight rows along the body. The ventral rows show abrasive damage along the entire length of the fish that gets worse with age. Impact damage to head and tail plates gets more severe and occurs at higher rates with age. The observed damage rates and the large investment in mineralization of the armor suggest that it is not just for show, but is a functional defensive structure. We cannot say what the armor is defense against, but the abrasive damage on the ventrum implies their benthic lifestyle involves rubbing on the substrate. The impact damage could result from predatory attacks or from intraspecific combat.

To date there are few detailed and quantitative studies investigating the evolution of the tooth shape and function in Aglyphous snakes in relation to diet. To study dental adaptations to diet, a lineage that is of particular interest due to its large range of adult body sizes, is the one including dwarfed snakes of the genus Eirenis and their immediate sister group, whip snakes of the genus Dolichophis. A considerable evolutionary decrease in the size is observed from a Dolichophis-like ancestor to the miniature Eirenis, coupled with a considerable shift in their diet from a regime consisting mainly of endotherms with endoskeleton to ectotherms bearing a hard exoskeleton. Maxilla, palatine, pterygoid and dentary teeth were examined in an adult and a juvenile of Dolichophis schmidti, one Eirenis punctolineatus and one Eirenis persicus. 3D Geometric Morphometrics comparison revealed maxilla and palatine teeth of the E. persicus are blunt and conical shape while those teeth are sharp and elongated in E. punctatolineatus as well as the adult and juvenile D. schmidti. A similar difference could be noted for the pterygoid teeth. In contrast, the dentary teeth are not as different among the examined snakes. Blunt and conically shaped teeth, as observed in E. persicus, seem to be more adapted for biting hard bodied, arthropod prey, while sharp and elongated teeth in Dolichophis and E. punctatolineatus, are specialized for puncturing endotherm prey. The results of a finite element analysis confirms that during biting a hard bodied prey, the generated stresses in E. persicus tooth is mostly confined to the tip of the tooth and mostly well below the von Mises yield criterion the tooth. In contrary, D. schmidti tooth appears less well suited for biting a hard prey since the generated stresses widely distribute across the tooth with values roughly 2 to 3 times higher than the von Mises yield criterion of the tooth. A lower degree of specialization that was observed among the dentary teeth in the examined snakes suggest a similar functional constraint in pushing the prey against the upper tooth rows.

The dermoskeleton of the earliest vertebrates is well known but their endoskeleton is thought to have been largely cartilaginous until the Late Silurian. We confirm that the dermal plates of Astraspis are three-layered, with a superficial layer of enameloid and orthodentine, a middle layer of aspidin and a basal layer of lamellar acellular bone. This dermoskeleton is found in association with globular calcified cartilage, indicating the presence of a partially mineralized endoskeleton. In addition to the classical three-layered organization, some dermal plates exhibit alignments of chondrocyte-like lacunae, very similar to a pattern typical of chondroid metaplastic bone, previously unknown in early vertebrates. This discovery implies the presence of a proliferative cartilage, hitherto only known in Osteichthyans. This discovery indicates that a pattern similar to the first step of endochondral ossification was already present in the earliest vertebrates.

Males of many Psylloidea are known to possess a characteristic structure at the functional hub of their reproductive apparatus, between afferent and efferent passage of seminal fluid. The structure is a squat, cylindrical endoskeleton consisting of two sections. Classical authors named them as ‘sperm pump’ and ‘ejaculatory duct’, based on superficial resemblance to a spring-loaded, thimble-shaped cylinder, encircled by smooth, vertical columns interpreted to be muscles which, when contracted, compress the cylinder and affect seminal fluid discharge. The discovery of numerous spherules of unknown composition and function in and around the columns of the Asian citrus psyllid male genitalia invoked rigorous scrutiny of the classical literature for evidence to support its claims, and determined that the grounds for vetting the structure as a sperm pump were fully teleological. This paper raises several objections to modern acceptance of this classical interpretation, presenting them as problematic, thought-provoking, and sometimes controversial anatomical features. The two sections are herein called ‘drum’ and ‘spout’. As an endoskeleton, the sections are an invagination of the exoskeleton and therefore cannot receive seminal fluid into their hollow. A phallus is identified inside an aedeagal tube, indicating that it is the ejaculatory duct—the tube, drum, and spout are considered its housing. A sheath envelopes the drum and is directly continuous with the spout hypodermis, another problematical feature raising the question of whether it is detached from adherence to the drum cuticles. Also, there are four afferent tubes but only two openings in the drum to receive their seminal fluids.

Although biodegradable membranes are essential for effective bone repair, severe loss of mechanical stability because of rapid biodegradation, soft tissue invasion, and excessive immune response remain intrinsically problematic. Inspired by the exoskeleton-reinforcing strategy found in nature, we have produced a Ti-infiltrated chitin nanofibrous membrane. The membrane employs vapor-phase infiltration of metals, which often occurs during metal oxide atomic layer deposition (ALD) on organic substrates. This metal infiltration manifests anomalous mechanical improvement and stable integration with chitin without cytotoxicity and immunogenicity. The membrane exhibits both impressive toughness (∼13.3 MJ·m

In order to characterize the molecular bases of mineralizing cell evolution, we targeted type X collagen, a nonfibrillar network forming collagen encoded by the Col10a1 gene. It is involved in the process of endochondral ossification in ray-finned fishes and tetrapods (Osteichthyes), but until now unknown in cartilaginous fishes (Chondrichthyes). We show that holocephalans and elasmobranchs have respectively five and six tandemly duplicated Col10a1 gene copies that display conserved genomic synteny with osteichthyan Col10a1 genes. All Col10a1 genes in the catshark Scyliorhinus canicula are expressed in ameloblasts and/or odontoblasts of teeth and scales, during the stages of extracellular matrix protein secretion and mineralization. Only one duplicate is expressed in the endoskeletal (vertebral) mineralizing tissues. We also show that the expression of type X collagen is present in teeth of two osteichthyans, the zebrafish Danio rerio and the western clawed frog Xenopus tropicalis, indicating an ancestral jawed vertebrate involvement of type X collagen in odontode formation. Our findings push the origin of Col10a1 gene prior to the divergence of osteichthyans and chondrichthyans, and demonstrate its ancestral association with mineralization of both the odontode skeleton and the endoskeleton.

The somasteroids are Lower Palaeozoic star-shaped animals widely regarded as ancestors of Asterozoa, the group of echinoderms that includes brittle stars and starfish. However, the origin of asterozoans, the assembly of their distinctive body organization, and their relationships with other Cambrian and Ordovician echinoderms remain problematic owing to the difficulties of comparing the endoskeleton between disparate groups. Here, we describe the new somasteroid Cantabrigiaster fezouataensis , a primitive asterozoan from the Early Ordovician Fezouata Lagerstätte in Morocco. Cantabrigiaster shares with other somasteroids a unique endoskeletal arm organization and the presence of rod-like virgal ossicles that articulate with the ambulacrals, but differs from all other known asterozoans in the absence of adambulacral ossicles defining the arm margins, evoking parallels with non-asterozoan echinoderms. Developmentally informed Bayesian and parsimony phylogenetic analyses, which reflect the homology of the biserial ambulacral ossicles in Palaeozoic echinoderms according to the extraxial–axial theory, recover Cantabrigiaster as the earliest divergent stem-group asterozoan. Our results illuminate the ancestral morphology of Asterozoa, and clarify the affinities of problematic Ordovician Asterozoa. Bayesian inference and parsimony demonstrate that somasteroids represent a paraphyletic grade within stem- and crown-group Asterozoa, whereas stenuroids are paraphyletic within stem-group Ophiuroidea. Our results also offer potential insights on the evolutionary relationships between asterozoans, crinoids and potential Cambrian stem-group representatives.

Anatomy of the adult and the first-instar nymph of Liposcelis bostrychophila (Psocoptera, Liposcelididae) is described in detail for the first time based on series of sections and 3D computer reconstruction. Despite its tiny size, no strong structural simplification is observed in Liposcelis. The main features of the anatomy of this species associated with miniaturization are the merging of individual skeletal elements and simplification of the endoskeleton in the nymph, lack of the midgut muscles, simplification of the tracheal and circulatory systems, oligomerization and concentration of ganglia, asymmetry of the central nervous system in the nymph, and the absence of several muscles. Changes in the relative volumes of organs during the postembryonic development of Liposcelis are analyzed and compared with other minute insects.

Anatomy of adults of Trichogramma evanescens (Hymenoptera: Trichogrammatidae) is described in detail for the first time based on series of sections and 3D computer reconstruction. The complex structure of the exoskeleton and musculature (except for reductions of individual muscles) is preserved in T. evanescens despite its tiny size. Considerable simplification is observed in the structure of the intestine, tracheal and circulatory systems, and in the reduced number of Malpighian tubules. Thus, the smallest Hymenoptera (Mymaridae and Trichogrammatidae) demonstrate both the effects of miniaturization universal for insects (reduction of the head endoskeleton, circulatory and respiratory systems) and specific ones.

Anatomy of the adult fairyfly Anaphes flavipes (Hymenoptera, Mymaridae) is described in detail for the first time, based on series of sections and 3D computer reconstruction. Despite its tiny size, A. flavipes does not demonstrate strong morphological simplification, except for the merging of certain skeletal elements, a slight simplification of endoskeleton, lack of midgut muscles, a reduced number of Malpighian tubules, simplification of the tracheal and circulatory systems, asymmetry of the central nervous system, and the absence of several muscles.

With aim to report the ontogeny of the osseous elements of the carapace in Peurodiras, 62 embryos and 43 nestlings of Podocnemis expansa were collected and submitted to the clearing and staining technique of bones and cartilages and study of serial histological slices. The carapace has mixed osseous structure of endo and exoskeleton, formed by 8 pairs of costal bones associated with ribs, 7 neural bones associated with neural arches, 11 pairs of peripheral bones, 1 nuchal, 1 pygal and 1 suprapygal. This structure begins its formation in the beginning of stage 16 with the ossification of the periosteal collar of the ribs. With exception of the peripheral bones, the other ones begin their ossification during the embrionary period. In histologic investigation it was found that the costal bones and neural bones have a close relation to the endoskeleton components, originating themselves as intramembranous expansions of the periosteal collar of the ribs and neural arches, respectively. The condensation of the mesenchyme adjacent to the periosteal collar induces the formation of spikes that grow in trabeculae permeated by fibroblasts below the dermis. The nuchal bone also ossifies in an intramembranous way, but does not show direct relation to the endoskeleton. Such information confirms those related to the other Pleurodira, mainly with Podocnemis unifilis, sometimes with conspicuous variations in the chronology of the ossification events. The formation of dermal plates in the carapace of Pleurodira and Criptodira follow the same pattern. Resumo: Com objetivo de relatar a ontogenia dos elementos ósseos da carapaça em Pleurodiras, coletaram-se 62 embriões e 43 filhotes de Podocnemis expansa que foram submetidos à técnica de clareamento e coloração dos ossos e cartilagens e pelo estudo cortes histológicos seriados. A carapaça possui estrutura óssea mista de endo e exoesqueleto, sendo formada por 8 pares de ossos costais associados às costelas, 7 ossos neurais associados aos arcos vertebrais, 11 pares de ossos periféricos, 1 nucal, 1 pigal e 1 supra-pigal. Esta estrutura começa sua formação no início do estágio 16 com a ossificação do colar periostal das costelas. Com exceção dos ossos periféricos, os demais iniciam sua ossificação durante o período embrionário. A investigação histológica explicitou que os ossos costais e neurais possuem uma estreita relação com componentes do endoesqueleto, originando-se como expansões intramembranosas do colar periostal das costelas e dos arcos neurais, respectivamente. A condensação do mesenquima adjacente ao colar periostal induz a formação de espiculas que crescem em trabéculas permeadas por fibroblastos abaixo da derme. O osso nucal, também se ossifica de maneira intramembranosa mas não apresenta relação direta com o endoesqueleto. Tais informações corroboram àquelas relatadas para os demais Pleurodiras, principalmente com Podocnemis unifilis, outrora com variações conspícuas na cronologia dos eventos de ossificação. A formação das placas dérmicas da carapaça em Pleurodira e Criptodira seguem um mesmo padrão.

Rehabilitation engineering plays an important role in designing various autonomous robots to provide better therapeutic exercise to disabled patients. Hence it is necessary to study human musculoskeletal system and also needs to be presented in scientific manner in order to describe and analyze the biomechanics of human body motion. This review focuses on lower appendicular musculoskeletal structure of human body to represent joints and links architectures; to identify muscle attachments and functions; and to illustrate muscle groups which are responsible for a particular joint movement. Firstly, human lower skeletal structure, linking systems, joint mechanisms, and their functions are described with a conceptual representation of joint architecture of human skeleton. This section also represents joints and limbs by comparing with mechanical systems. Characteristics of ligaments and their functions to construct skeletal joints are also discussed briefly in this part. Secondly, the study focuses on muscular system of human lower limbs where muscle structure, functions, roles in moving endoskeleton structure, and supporting mechanisms are presented ellaborately. Thirdly, muscle groups are tabulated based on functions that provide mobility to different joints of lower limbs. Finally, for a particular movement action of lower extremity, muscles are also grouped and tabulated to have a better understanding on functions of individual muscle. Basically the study presents an overview of the structure of human lower limbs by characterizing and classifying skeletal and muscular systems.KEYWORDS: Musculoskeletal system; Human lower limbs; Muscle groups; Joint motion; Biomechatronics; Rehabilitation.

Cuvillierinella salentina Papetti and Tedeschi, 1965 and its related species of the Rhapydioninidae family are widely distributed in the Western Mediterranean region by Campanian–Maastrichtian time. C. salentina, the type species of the genus, is studied in rich populations from its Italian type locality, and several other spots from Greece and Spain. It shows great variability: the well-known type coexists with streptospiral tests almost devoid of endoskeleton and wholly planispiral tests with fine mesh-like endoskeleton, as well as many intermediates. Such populations reflect the large capacity of evolution of at least the group of miliolids from which these populations are derived, if not the species itself. The genera Murciella and Cyclopseudedomia are probably the most direct offshoots, but other taxa appear to arise from this species or at least from the same stock of origin. In the same genus and at the same time (middle part of Campanian age, “CsB6a” zone), two new species are described, both hesitating between the streptospiral and planispiral coiling: – C. fluctuans nov. sp., from Greece, A tests being either streptospiral or planispiral, with primary and secondary chamberlets taking the aspect of polygonal isodiametric network and – C. perisalentina nov. sp., from Italy, with persistent streptospiral coiling and disordered arrangement of secondary chamberlets which allow us to consider its relation with species of the genus Pseudochubbina, hitherto of completely enigmatic origin. Assigned to the same genus, from Upper Campanian–Lower Maastrichtian time (“CsB6b” zone), C. aff. pylosensis, probably related to C. pylosensis, is studied from several populations, and constitutes, with the above mentioned species, what is called C. gr. salentina. Based on material from the CsB6b zone, the new genus Metacuvillierinella nov. gen. is introduced; M. decastroi nov. sp., type species of the new genus, known from Greece and Italy, shows characters common to C. gr. salentina, such as milioline to streptospiral nepionic coiling, large endoskeleton mesh, associated with some original characters, such as the unusual conjunction of the advolute coiling and absence of any final unrolling together with very low dimorphism of generation; this results in flat tests, often sigmoid shaped in axial section, very rare in the family. Thus, the genus Cuvillierinella, and especially C. salentina, appears as a possible source, or at least not far from the origin, of a number of taxa related to one another, constituting a large part of the Rhapydioninidae family. They are gathered together inside the new subfamily Cuvillierinellinae, distinct from the subfamily Rhapydionininae sensu stricto (comprising Rhapydionina and Fanrhapydionina) which makes a different and parallel branch, from Upper Campanian (CsB6b zone) to the end of Cretaceous time (CsB7 zone).

Hydrogel composites that respond to stimuli can form the basis of new classes of biomimetic actuators and soft robotic components. Common latex microspheres can be assembled and patterned by AC electric fields within a soft thermoresponsive hydrogel. The field-oriented particle chains act as endoskeletal structures, which guide the macroscopic bending pattern of the actuators.

Seahorses, which have been used in Chinese traditional medicine, are poor swimmers and easily affected by regional ecological conditions. In this study, we investigated the bioaccumulation of nine metals in different tissues of four seahorse species (Hippocampus trimaculatus, H. histrix, H. kelloggi, and H. kuda) from six locations along the Chinese coast. The present study found relatively low concentrations of metals in the seahorses compared with those in other marine fishes. There was a location-dependent variation in metal concentrations in the seahorses, especially between developed and less developed cities. Results also showed metal concentrations varied among different seahorse species and tissues, with H. kelloggi having higher bioaccumulation ability compared with H. trimaculatus and higher metal levels were found in visceral mass, muscle, and skin tissues than those in brain, lips gill, endoskeleton, and exoskeleton tissues in the seahorses. Among different metals, Mg had the highest tissue concentrations in all the seahorses, followed by Al and Mn.

Due to their cartilaginous endoskeleton and the continuous tooth replacement, the chondrichthyan fossil record predominantly consists of isolated teeth, which offer diagnostic features for taxonomic identifications, but only provide very limited information of an organism's life history. In contrast, the calcified vertebral centra of elasmobranchs (sharks, skates and rays) yield important information about ecological and biological traits that can be utilized for constructing age-structured population dynamic models of extant species and palaeoecological reconstructions of such aspects in extinct groups. Here, we describe two large shark vertebrae from the Santonian (Upper Cretaceous) of Spain, which show a unique combination of characters (asterospondylic calcification pattern, with concentric lamellae and numerous parallel bands that are oriented perpendicular) that is only known from ptychodontid sharks, a distinct, extinct group of giant durophagous sharks of the Cretaceous era. Based on linear regression models for large extant sharks a total length between 430 and 707cm was estimated for the examined specimen. Our results indicate that ptychodontid sharks were large viviparous animals, with slow growth rates, matured very late and, therefore, show typical traits for K-selected species. These traits combined with a highly specialized feeding ecology might have played a crucial role for the success but also, eventually, extinction of this group.

Soft grippers are suitable for gripping various objects without damage owing to their high flexibility. But current soft grippers have a general problem of insufficient gripping force. To grip objects with different mass and sizes on assembly line safely and reliably, a novel pneumatic soft gripper with a jointed endoskeleton structure was developed and fabricated successfully. The actuation and force bearing functions of the gripper were separated to increase the gripping force. Moreover, to control the output force of the finger tip of the soft gripper, a fuzzy auto-tuning PID controller was designed and the relevant parameters of the controller were determined. Furthermore, a test platform with the designed fuzzy auto-tuning PID controller was developed to control the output force of the finger tip. The test results showed that the controller was able to maintain the desired target output force with a maximum deviation of 0.6 N. At last, the soft gripper was used to grip material objects for testing. From the experiment, it indicated that the output force of the finger tip can reach up to the desired values accurately and various objects can be gripped safely and reliably.

Anthropogenic CO2 – driven ocean acidification (OA) is causing a decrease in seawater pH and the saturation state of calcium carbonate minerals, compromising the ability of calcifying species to produce and maintain their skeletons. Sea urchins are ecologically important calcifying species and we investigated the impacts of long-term (9 month) exposure to near-future OA (Ambient – pHNBS 8.01; OA – pHNBS 7.6) on the skeleton microstructure of Heliocidaris erythrogramma using scanning electron microscopy (SEM), micro-computed tomography (μCT) and nanoindentation. SEM revealed that the youngest plates (apical plates) which had likely grown in experimental conditions had larger pores in the OA group (pore surface area ~ 72% larger) compared with those of urchins maintained in ambient pH. High-resolution, μCT 3-D reconstructions of the apical plates revealed that the experimental OA treatment urchins had a ~14% greater porosity and ~17% less biomineral, suggesting an inability to finely regulate skeletogenesis. The mid-test ambital plates established prior to this study did not show any OA associated change in porosity. Nanoindentation of the apical plates indicated that OA reduced skeletal hardness and elasticity. Stereom pore size is a key trait of the sea urchin endoskeleton and increased porosity in H. erythrogramma is likely to impact its biological functions as well as its biomechanical capacity to defend against predation and physical disturbances.

none 5 si The endoskeleton of echinoderms (Deuterostomia: Echinodermata) is of mesodermal origin and consists of cells, organic components, as well as an inorganic mineral matrix. The echinoderm skeleton forms a complex lattice-system, which represents a model structure for naturally inspired engineering in terms of construction, mechanical behaviour, and functional design. The sea urchin (Echinodermata: Echinoidea) endoskeleton consists of three main structural components: test, dental apparatus, and accessory appendages. Although, all parts of the echinoid skeleton consist of the same basic material, their microstructure displays a great potential in meeting several mechanical needs according to a direct and clear structure-function relationship. This versatility has allowed the echinoid skeleton to adapt to different activities such as structural support, defence, feeding, burrowing, and cleaning. Although, constrained by energy and resource efficiency, many of the structures found in the echinoid skeleton are optimized in terms of functional performances. Therefore, these structures can be used as role models for bio-inspired solutions in various industrial sectors such as building constructions, robotics, biomedical and material engineering. The present review provides an overview of previous mechanical and biomimetic research on the echinoid endoskeleton, describing the current state of knowledge and providing a reference for future studies. open Perricone Valentina;,Grun, Tobias, Marmo Francesco, Langella Carla, Candia Carnevali Maria Daniela Perricone, Valentina; Grun, Tobias; Marmo, Francesco; Langella, Carla; Candia Carnevali Maria, Daniela