Claw Shape Research Articles

Integrative redescription of the Xerobiotus euxinus Pilato, Kiosya, Lisi, Inshina & Biserov, 2011 (Tardigrada: Eutardigrada: Macrobiotidae) population from Ukraine

Using integrative taxonomy, we redescribe an eutardigrade Xerobiotus euxinus Pilato et al. 2011 based on material from the type locality and additional population from the Black Sea Biosphere Reserve in the south of Ukraine. Integrative redescription is based on morphological and morphometric data of animals and eggs from both phase contrast light microscopy (PCM), as well as, from scanning electron microscopy (SEM), and four DNA markers, three nuclear (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial (COI). Originally, the species was described solely based on adults’ morphology. The uncorrected genetic distances indicated that X. euxinus is the most similar to X. gretae with a p-distance value of COI fragment. Morphologically, X. euxinus differs from all Xerobiotus taxa mainly by the shape of claws on legs IV, but also by some other morphological and morphometrical characters of eggs and animals.

Claw shape variation in oribatid mites of the genera Carabodes and Caleremaeus: exploring the interplay of habitat, ecology and phylogenetics.

Claws are a commonly observed biological adaptation across a wide range of animal groups. They serve different functions and their link to evolution is challenging to analyze. While there are many studies on the comparative anatomy and morphology of claws in reptiles, birds and several arthropods, knowledge about claws of soil-living oribatid mites, is still limited. Recent research on intertidal oribatid mites has shown that claw shape is strongly correlated with microhabitat and is subject to ecological selective pressures. However, the selective constraints shaping claws in terrestrial oribatid mites are still unknown. In this study, 300 specimens from 12 different species and two genera were examined. Geometric morphometrics were used to quantify claw length and curvature, and to analyze two-dimensional claw shape. In combination with molecular phylogenetic analyses of investigated populations phylogenetic signal was quantified within genera using Blomberg's K and random replicates. Additionally, ecological information on the investigated species was gathered from previous studies and compiled into tables. The claw shapes of Carabodes species vary moderately, with the three species C. reticulatus, C. rugosior and C. tenuis deviating the most from the others. These three species are only found in a small number of habitats, which may require a more specialized claw shape. Our results show that there is a phylogenetic influence on claw shape in Carabodes but not in Caleremaeus. Additionally, habitat specificity and lifestyle were found to have ecological impact on claw shape in both genera. The present results demonstrate that characteristics of the claws of terrestrial oribatid mites are correlated with ecology, but this correlation is apparently weaker than in intertidal oribatid mites that are prone to strong external forces.

Diversity and distribution of crustaceans in the mangrove forest of Nusa Lembongan, Bali, Indonesia

Abstract. Ginantra IK, Muksin IK, Joni M, Wijaya IMS. 2023. Diversity and distribution of crustaceans in the mangrove forest of Nusa Lembongan, Bali, Indonesia. Biodiversitas 24: 4533-4541. Research on the diversity and distribution of crustaceans in the mangrove forest of Nusa Lembongan, Bali, Indonesia was conducted from March to June 2022. Sampling was carried out using the quadratic method at seven mangrove forest sites. The identification of crustacean species is based on morphological characteristics, namely carapace color, claw shape, legs, and body size. Crustacean density was determined based on the number of individuals per unit area of mangrove forest, diversity was determined by the Shanon-Wiener Index, and crustacean distribution was determined based on the frequency of species presence in each square at the seven study sites. Environmental factors were also measured: Mangrove vegetation, substrate type, temperature, pH, and salinity. The results showed that 12 species of crustaceans were found, consisting of 10 species of crabs and two species of hermit crabs. Several species of crabs are quite dominant in the mangroves of Nusa Lembongan namely Sesarma pictum (De Haan, 1835), with a density of 7 individuals/5 m2, Uca tetragonon (Herbst, 1790) of 3.7 individuals/5 m2, Uca rosea (Tweedie, 1837) with a density of 2.5 individuals/ 5 m2, and Uca triangularis (A. Milne-Edwards, 1873) with a density of 2 individuals/5 m2. Environmental factors support the life of Nusa Lembongan crustaceans, namely the type of substrate, mostly muddy and sandy, diverse species of mangrove plants, both true and associated mangroves, water temperature 27.70-29.00°C, pH 6.88-7.15 and water salinity ranging from 27.83-31.53‰. Crustacean diversity is included in the moderate category with their diversity index. There are three crab species with moderate to frequent (absolute) frequency of presence, namely U. rosea (Fi: 57.15%), S. pictum (Fi: 71.43%), and U. tetragonon (Fi: 85.71%). These species are present in four to six mangrove forest sites.

From color to shape: ontogenetic shifts in traits of the freshwater crab Dilocarcinus pagei (Brachyura: Trichodactylidae)

Crustaceans usually undergo a series of changes after the puberty molt. These changes are often associated with size increases in the body and in structures such as the abdomen and claws so that they can achieve higher reproductive fitness. These morphological changes allow the animal to fight, court, and signal for its conspecific with better performance. To compare ontogenetic changes, we used the freshwater crab Dilocarcinus pagei Stimpson, 1851 as a model. We analyzed differences in carapace and claw shape, force generation (via the apodeme area), morphological integration of claws, and color changes among demographic groups. Adult crabs had an increase in claw and carapace size followed by a shape change that makes the claws more robust. In addition, the animals changed from a dark brown coloration in juveniles to a dark red coloration in adult males, while adult females presented a dark red-brown coloration. Presumably, phenotypic changes may enhance crabs’ ability to obtain different food sources, as well as fight for sexual partners, and manipulate females during courtship. Color changes can be a strategy by which adult males can signal to females, while the dark brown coloration of juveniles can help in camouflage in the substrate.

First insights into the morphological development of tarsal claws in terrestrial oribatid mites

Mites occupy a wide range of ecological niches and are good models to investigate correlations of morphological structures and ecology in arthropods. Here we compare tarsal claw shape of three terrestrial oribatid mite species with different ecological backgrounds. By means of geometric morphometrics we describe shape, size and development of the tarsal claw of the monodactyl mite species Lamellovertex caelatus and Platynothrus peltifer, and the tridactyl Melanozetes meridianus. After analysis of juvenile and adult mites we can distinguish the euryoecious P. peltifer and the alpine M. meridianus with similar claw curvatures from the saxicolous L. caelatus with considerably less curved claws. The claw height of P. peltifer, on the other hand, is remarkably higher than in the other two species. Despite these differences, no correlation between claw characteristics and environmental factors can be inferred. During the development of the mites, claw curvature and shape remain constant from protonymph to adult and claw size increases direct proportionally with body growth in all studied species. Neither the monodactyl nor the tridactyl species show any specific changes in claw characteristics.

Sharp claws beneath our feet – the diversity of tarsal attachment devices of oribatid mites (Acari, Chelicerata, excluding Astigmata) – a review

ABSTRACT The majority of animals possess claws on their legs and they are mainly used for keeping attached to the substrate. Recent studies on claw shapes and function suggest that claws are not just simple attachment devices but highly specialized morphological traits bearing information about lifestyle, ecology and evolution. In that respect, knowledge about claws is extremely scarce, especially in highly diverse groups, as for example the oribatid mites, with more than 11000 named species occurring in every environment all over the world. This review summarizes all information about claws and relevant aspects for this large group of arthropods. There is a huge variety of ambulacral claw morphologies present in oribatid mites and this diversity does not follow a strict phylogenetic or systematic pattern. Lifestyle and ecology apparently play an important role in shaping claw morphologies. Intertidal oribatid mites are mostly characterized by having single large tarsal claws to withstand tidal flooding, a similar tendency can be found in terrestrial limnic species where monodactylous species prevail. Additionally, fresh-water Oribatida often show scaliform and barbed distal tarsal setae which cooperate with the claws helping the mites to stick to water plants. Claws of arboreal mites are often equipped with adhesive pads “pulvilli” allowing them to walk on smooth plant surfaces. Suction pads are also found in a few mites showing epilithic lifestyles and in mites being able to perform sudden evasive jumps. Claws of phoretic oribatid mites show in most cases no apparent adaptations but certain groups are equipped with highly modified claws allowing them to attach to specific structures of their hosts. Finally, this review gives an overview of all claw morphologies present in each larger phylogenetic oribatid mite group.

A new genus, Tuberocandona gen. nov. (Crustacea, Ostracoda, Candonidae) and past to present ostracod species diversity in Texas (USA)

A new ostracod genus, Tuberocandonagen. nov., was collected from Honeycut Hollow Springs, Texas, USA Morphological comparisons and cladistic analyses showed that the new genus displays several different features (e.g. presence of two tubercules on each of the valves, numbers of A1 segments, shape of A2 claws, shape and presence of two claw-like setae on the clasping organs, absence of d2 and dp setae on T2 and T3, absence of alpha and beta setae on Md, shape of hemipenis) from other genera of the tribe. Including the new species, the number of non-marine ostracods known from inland waters of Texas is now 118 species in 45 genera. With the aim of documenting ostracod biodiversity in Texas (USA) by including fossils, we sought documents published from 1927 to 2022 and were able to list 673 ostracod taxa belonging to 142 genera. Among the fossils, 73 ostracods were the oldest records during the Pennsylvanian period (ca. 310 mya), while there were only 42 taxa reported from the Holocene. The Eocene had the highest number of ostracods (126 taxa). In comparison, the living species had only 18 of 673 taxa that were considered nonmarine forms. There are only six species in common with the fossils and recent records. These results suggest the potential for relatively high ostracod species richness and diversity in Texas. This is indeed strongly supported by the present study and the described new genus and its type species (Tuberocandona leonidasisp. nov.).

Get to the point: Claw morphology impacts frictional interactions on rough substrates

Claws are a common anatomical feature among limbed amniotes and contribute to a variety of functions including prey capture, locomotion, and attachment. Previous studies of both avian and non-avian reptiles have found correlations between habitat use and claw morphology, suggesting that variation in claw shape permits effective functioning in different microhabitats. How, or if, claw morphology influences attachment performance, particularly in isolation from the rest of the digit, has received little attention. To examine the effects of claw shape on frictional interactions, we isolated the claws of preserved specimens of Cuban knight anoles (Anolis equestris), quantified variation in claw morphology via geometric morphometrics, and measured friction on four different substrates that varied in surface roughness. We found that multiple aspects of claw shape influence frictional interactions, but only on substrates for which asperities are large enough to permit mechanical interlocking with the claw. On such substrates, the diameter of the claw’s tip is the most important predictor of friction, with narrower claw tips inducing greater frictional interactions than wider ones. We also found that claw curvature, length, and depth influence friction, but that these relationships depend on the substrate’s surface roughness. Our findings suggest that although claw shape plays a critical role in the effective clinging ability of lizards, its relative importance is dependent upon the substrate. Description of mechanical function, as well as ecological function, is critical for a holistic understanding of claw shape variation.

Climbing and Clinging of Urban Lizards are Differentially Affected by Morphology, Temperature, and Substrate.

Urbanization alters the environment along many dimensions, including changes to structural habitat and thermal regimes. These can present challenges, but may also provide suitable habitat for certain species. Importantly, the functional implications of these habitat shifts can be assessed through the morphology-performance-fitness paradigm, though these relationships are complicated by interactions among habitat choice, other abiotic factors, and morphology across scales (i.e., micromorphology and gross anatomy). The common wall lizard (Podarcis muralis) is one example of a cosmopolitan and successful urban colonizer. Quantifying both shifts in morphology over time and morphology-performance relationships under various ecological contexts can provide insight into the success of species in a novel environment. To examine how morphological variation influences performance, we measured seven gross morphological characteristics and utilized scanning electron microscopy to obtain high-resolution images of a claw from individuals living in established populations in Cincinnati, Ohio, USA. We used a geometric morphometric approach to describe variation in claw shape and then compared the claws of contemporary lizards to those of museum specimens collected approximately 40 years ago, finding that claw morphology has not shifted over this time. We then performed laboratory experiments to measure the clinging and climbing performance of lizards on materials that mimic ecologically relevant substrates. Each individual was tested for climbing performance on two substrates (cork and turf) and clinging performance on three substrates (cork, turf, and sandpaper) and at two temperatures (24ºC and 34ºC). Clinging performance was temperature insensitive, but determined by substrate-specific interactions between body dimensions and claw morphology. Conversely, the main determinant of climbing performance was temperature, though lizards with more elongate claws, as described by the primary axis of variation in claw morphology, climbed faster. Additionally, we found strong evidence for within-individual trade-offs between performance measures such that individuals who are better at clinging are worse at climbing and vice versa. These results elucidate the complex interactions shaping organismal performance in different contexts and may provide insight into how certain species are able to colonize novel urban environments.

Exceptional preservation and foot structure reveal ecological transitions and lifestyles of early theropod flyers

Morphology of keratinised toe pads and foot scales, hinging of foot joints and claw shape and size all inform the grasping ability, cursoriality and feeding mode of living birds. Presented here is morphological evidence from the fossil feet of early theropod flyers. Foot soft tissues and joint articulations are qualitatively assessed using laser-stimulated fluorescence. Pedal claw shape and size are quantitatively analysed using traditional morphometrics. We interpret these foot data among existing evidence to better understand the evolutionary ecology of early theropod flyers. Jurassic flyers like Anchiornis and Archaeopteryx show adaptations suggestive of relatively ground-dwelling lifestyles. Early Cretaceous flyers then diversify into more aerial lifestyles, including generalists like Confuciusornis and specialists like the climbing Fortunguavis. Some early birds, like the Late Jurassic Berlin Archaeopteryx and Early Cretaceous Sapeornis, show complex ecologies seemingly unique among sampled modern birds. As a non-bird flyer, finding affinities of Microraptor to a more specialised raptorial lifestyle is unexpected. Its hawk-like characteristics are rare among known theropod flyers of the time suggesting that some non-bird flyers perform specialised roles filled by birds today. We demonstrate diverse ecological profiles among early theropod flyers, changing as flight developed, and some non-bird flyers have more complex ecological roles.

Two new tardigrade genera from New Zealand’s Southern Alp glaciers display morphological stasis and parallel evolution

Tardigrada is an invertebrate phylum that often constitutes a dominant micrometazoan group on glaciers worldwide. We investigated tardigrades residing in surface ice above the equilibrium line altitude (ELA) on three temperate glaciers of New Zealand’s Southern Alps. Morphological, morphometric and multilocus DNA analyses (CO1, 18S rRNA, 28S rRNA, ITS-2) revealed two new genera comprising four species, of which two are formally described here: Kopakaius gen. nov. nicolae sp. nov. and Kararehius gen. nov. gregorii sp. nov. The former is represented by three genetically distinct phyletic lineages akin to species. According to CO1, Kopakaius gen. nov. nicolae sp. nov. inhabits Whataroa Glacier only while the remaining two Kopakaius species occur on Fox and Franz Joseph Glaciers, suggesting low dispersal capabilities. Although morphological characteristics of the new genera could indicate affinity with the subfamily Itaquasconinae, phylogenetic analysis placed them confidently in the subfamily Diphasconinae. Kopakaius gen. nov. lack placoids in the pharynx similar with some Itaquasconinae, whereas dark pigmentation and claw shape aligns them with the glacier-obligate genus, Cryobiotus (subfamily Hypsibiinae), which is an example of parallel evolution. The second genus, Kararehius gen nov. could be classified as Adropion-like (subfamily Itaquasconinae), but differs greatly by genetics (placed in the subfamily Diphasconinae) as well as morphology (e.g., lack of septulum), exemplify deep stasis in Hypsibiidae. Our results suggest that glacier fragmentation during the Pleistocene triggered tardigrade speciation, making it a suitable model for studies on allopatric divergence in glacier meiofauna.

Analysis on Noise Source of Claw Pole Machine in Duplex Three-Phase and Belt-Driven System

The acoustic noise, which is generated in a belt-driven integrated starter and generator (BSG) system, is the recent issue. By many studies, it has been known that the noise can be caused by both radial and tangential components of electro-magnetic force. A duplex three-phase claw pole type machine is widely used in the BSG system. In this case, due to its structural feature and difficulty in control, additional noises at unexpected frequency can be generated. In this paper, a method to analyze noise sources was proposed and applied to a prototype that is the duplex three-phase and claw pole type machine designed for BSG system. First, the electro-magnetic force was calculated by a finite-element analysis considering the unbalanced current measured by the experiment. The obtained force was decomposed according to the frequency and then analyzed. Through the force harmonics, additional noises according to the frequency, which are generated by the unbalanced claw shape in the axial direction and current imbalance between phases, were deduced. Finally, the predicted noise sources were compared with the noise measured through the experiment.

A new species of Thraulus Eaton, 1881 (Ephemeroptera: Leptophlebiidae) from the Western Ghats, South India

Thraulus jacobusi sp. n. is described based on the nymphs collected from the Veerapandi River in the south of the Western Ghats. Thraulus jacobusi sp. n. may be distinguished from other oriental species of Thraulus Eaton, 1881 by the following combination of characters in the nymphs: labial palp ratio, maxillary palp ratio of segments II and III, the colouration of legs, shape and denticulation of claws, shape of tergalius I, and posterolateral spines on the tergum VIII and IX. Nymphal diagnostic keys to Indian species of Thraulus are provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:69019BD1-BE64-4186-8DA9-C67D28DD6135

Like parent, like child – Ontogenetic development of claws of intertidal arthropods (Acari, Oribatida) from different ecological niches

The shape of claws of adult air-breathing intertidal oribatid mites shows a strong correlation with ecology. As nothing is known about juvenile characteristics of this trait, the ontogenetic development of these attachment devices was studied for the first time with comprehensive geometric morphometric methods. In nine investigated species, claws of immature stages can be classified into the same ecological categories as adults, i.e. juveniles of several rock-dwelling species already show higher and stronger curved claw shapes with smaller claw angles, while juvenile instars of the single investigated mangrove-dwelling species possess lower and less curved claws with wider claw angles. For each species, claw curvature is almost static during the complete development and claw length grows directly proportional with increasing body size. Developmental changes in body size and weight are thus mainly compensated by a simple relative growth in size. Despite the finding that claw shapes of early developmental stages are already classifiable into ecological categories, their shapes also change slightly during development to become more ‘rock’, ‘mix’ or ‘mangrove’-like, respectively. The present results demonstrate that ecology is also the most important factor in shaping the claws of immatures and that attachment in the intertidal environment is vital for the survival of each mobile stage.

Outcome of Patients with Comminuted Fractures of Patella Treated with Claw Shape Plate, a case Series at a Tertiary Care Hospital

Introduction: Comminuted fractures of patella are usually dealt with partial or complete patellectomy which compromise the extensor mechanism. Claw plate is newly introduced device to fix comminuted fractures, which provide easy and efficacious method of preserving patella and is used in selected cases. Methods: This prospective observational case series was conducted at orthopaedic department Chandka Medical College (SMBBMU) Larkana from March 2020 to May 2021. Twenty one cases were selected via consecutive sampling with comminuted fracture of patella who were treated with newly introduced claw shape patellar plate. Age of patients was ranging from 18 years to 70 years. All patients were admitted in tertiary care hospital and were operated by senior surgeon. During procedure patella was approached through anterior mid line incision over knee, fracture reduced and fixed with claw shape patella plate. Post operatively patients were assessed on subsequent follow up visits and outcome of procedure was observed on the basis of functional (Clinical) and radiological results. The functional (clinical) outcome was measured on basis of Lysholm knee score and radiologically x-rays of knee were done to see union pattern. Final outcome of procedure was concluded after 6 month of operation. Results of all patients were compiled and analysed by using statistical package for Social Sciences (SPSS) Version 21 Results: Twenty one patients were enrolled in our study, among them 15(71.4%) were male and six (28.6) were female; the mean age of patients was 42.52 years. The mean length of operation was 55 minutes (40 to 72 minutes). Bone union on radiograph was observed at 20th weeks after surgery in all patients, mean age of fracture healing was 11.5 weeks, (Ranges from 6th to 20th week). At final evaluation found excellent results in 12 (71%) patients, five (29%) patients obtain good results, while four patients lost follow up. Conclusions: Partial or complete patellectomy can be avoided in comminuted patella fractures and patella can be preserved in these fractures by using claw shape patella plate. Keywords: Comminuted fractures, Patella, Claw plate.

Genetic parameter estimates for feet and leg traits in Red Angus cattle.

The objective of this study was to estimate genetic parameters for feet and leg traits, relationships within feet and leg traits, and relationships between feet and leg traits and production traits in Red Angus cattle. Subjective scores for 14 traits including body condition score (BCS), front hoof angle (FHA), front heel depth (FHD), front claw shape (FCS), rear hoof angle (RHA), rear heel depth (RHD), rear claw shape (RCS), size of hoof (SIZE), front side view (FSV), knee orientation (KNEE), front hoof orientation (FHO), rear side view (RSV), rear view (RV), and a composite score (COMP) were collected by trained evaluators on 1,720 Red Angus cattle. All traits except COMP were scored as intermediate optimum traits. Performance data, and EPD were obtained on all animals measured and a three-generation pedigree was obtained from the Red Angus Association of America (RAAA) that contained 13,306 animals. Data were modeled using a linear bivariate animal model with random additive genetic and residual effects, and fixed effects of age and contemporary group (herd-year) implemented in ASREML 4.0. Heritability estimates of BCS, FHA, FHD, FCS, RHA, RHD, RCS, SIZE, FSV, KNEE, FHO, RSV, RV, and COMP were 0.11, 0.20, 0.17, 0.09, 0.19, 0.25, 0.17, 0.36, 0.16, 0.17, 0.17, 0.30, 0.14, and 0.12, respectively. These results demonstrate feet and leg traits are lowly to moderately heritable. Strong, positive genetic correlations were observed between FHA and FHD (0.89), FHA and RHA (0.88), FHD and RHA (0.85), FHA and RHD (0.85), FHD and RHD (0.94), and FHO and KNEE (0.95), indicating these traits were highly related to each other. Strong and negative genetic correlations were observed between KNEE and FSV (-0.59) and FHO and FSV (-0.75). The strongest Pearson correlation between front limb traits (FHA, FHD, FSV, FHO, KNEE, and COMP) and Stayability EPD (STAY) was FSV (r = 0.16) and for rear limb traits (RHA, RHD, RCS, RSV, RV, and COMP) and STAY was RCS (r = -0.12). This suggests cattle with more slope to the angle of the shoulder and cattle with less evidence of hoof curl may stay in the herd longer. Further investigation into the economic viability of feet and leg trait genetic prediction with a larger population of animals is required to help validate these findings.

Zealandiscus gen. nov., a New Genus Erected in the Family Echiniscidae Thulin, 1928 (Heterotardigrada)

A new heterotardigrade genus, Zealandiscus gen. nov., is erected for the species Echiniscus palmai. Dorsal plates' sculpturing with sparsely distributed large hemispherical protuberances and very tiny granules distinguish this genus from all known members of the genus Echiniscus. The new genus is most similar to the genus Kristenseniscus by the shape of claws and some aspects of dorsal cuticle i.e. presence of sparsely distributed quite large hemispherical protuberances. However, in the newly erected genus dorsal plates' sculpture is “double-like” (i.e. it is composed of two types of granulation visible in different focal planes), hemispherical protuberances are larger and not so dense, dorsal plates are not subdivided into smaller subplates, median plate m3 and ventral subcephalic plates are present. Such autapomorphies fully justify erection of the new genus, even if the genetic data are at present unavailable.

Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia

Abstract. Ginantra IK, Muksin IK, Joni M. 2021. Crab diversity as support for ecotourism activities in Pejarakan Mangrove Forest, Buleleng, Bali, Indonesia. Biodiversitas 22: 4139-4145. This research aims to determine the diversity of crabs to support ecotourism activities in the coastal mangrove forest of Pejarakan Buleleng. Sampling of crabs was carried out using the square method, as many as 23 squares were spread over three mangrove zones, namely the front zone, the middle zone, and the rear zone. The number of individual crustacean species in each square plot was counted. Crab identification is based on morphological characters (shell color, claw shape, body-color, body size). Habitat use activities are observed directly. The diversity of crabs was calculated using the Shannon-Wiener diversity index. The results showed that in the coastal mangrove area of Pejarakan Buleleng, there were 11 species of crabs (9 species of crabs and 2 species of hermit crabs). Species diversity is in the medium category (index 2.25) and evenness index is high (E = 0.93, mangrove conditions are stable). The seaward mangrove zone shows a higher diversity of crab species than the middle zone and the rear zone. The species of crabs that are quite abundant in the three zonings are Uca vocans, Chiromanthes sp., and Coenobita sp. Characteristics of crabs, activities, habitat use in mangrove zoning are attractions for ecotourism activities.

Suitable claw shape design for improving the magnetic properties of forged claw pole parts in generator

High power-generation efficiency can be achieved by optimising the shape of the claw pole used as automobile generators. The working process of the stator and rotor in the claw pole generator was simulated using the finite-element method. First, one of the eight typical claw pole types commonly used in industry was selected. Then, orthogonal optimisation was performed based on the simulation results, yielding an optimal claw shape design. To examine the adaptability of the designed claw pole to shape change, the non-destructive test for evaluating the magnetic properties of claw pole (NDTEM) was employed. Finally, a claw pole with an optimal shape was forged, and its magnetic induction intensity was assessed using the NDTEM. The results indicated that compared with the unoptimised claw pole, the magnetic induction intensity of the optimised claw pole increased by a maximum of 8.11% and its weight reduced by 4.86%. This optimisation effectively improved the efficiency of power generation and achieved the lightweight of the claw pole.

Social conquest of land: Sea-to-land changes in shell architecture and body morphology, with consequences for social evolution

Architecture, like nests, burrows, and other types of fortresses, may have played an important role in the evolution of social life on land. However, few studies have examined architecture in organisms that transitioned from sea to land to test how and why architectural and morphological changes might have jointly impacted social evolution. Here I contrasted the shell architecture and body morphology of two of the phylogenetically most closely-related land versus sea species of hermit crab (the terrestrial hermit crab, Coenobita compressus, and the marine hermit crab, Calcinus obscurus), as well as the original builder of their shells (the gastropod, Nerita scabricosta). In contrast to the shells of gastropods and marine hermit crabs, only the shells of terrestrial hermit crabs were architecturally remodeled, with no columella inside for the occupants to grip upon to resist eviction. The bodies of terrestrial hermit crabs were also significantly more exposed outside the enlarged openings of their remodeled shells, whereas the substantially smaller-bodied marine hermit crabs were safeguarded deep within the recesses of their unremodeled shells. Ultimately, these changes in shell architecture and body morphology likely had consequences for social evolution on land, making conspecifics not only more dependent upon one another for homes, but also potentially easier to evict. Further changes in claw shape on land (with the claws of terrestrial hermit crabs becoming shorter, wider, and thicker) may have evolved to help offset their heightened danger of social eviction, acting as a more effective door against conspecifics.