The genus Sinocyclocheilus represents the world's most diverse cavefish radiation, typically exhibiting troglomorphic traits such as scale regression and eye degeneration. Notably, Sinocyclocheilus macrolepis from a tributary of the Long-Jiang of the Pearl River retains fully developed scales despite inhabiting epigean streams, a rare trait among its cave-adapted congeners. The Sinocyclocheilus specimens collected from a tributary of the Hongshui-He of the Pearl River in South Guizhou exhibit overall similarities to S. macrolepis with fully developed scales and normal eyes. Phylogenetic analyses using mitochondrial Cyt b and ND4 genes reveal that these specimens represent a novel species, sister to S. macrolepis but with significant genetic divergence, and closely related to Sinocyclocheilus ronganensis. This new species was designated as Sinocyclocheilus pingchowensis in this study. Morphologically, S. pingchowensis differs from S. macrolepis in lateral-line scale counts, head width, gill-opening position and pelvic-fin ray counts. S. pingchowensis along with S. macrolepis and S. ronganensis are herein defined as the S. macrolepis group based on the shared synapomorphies and phylogenetic affinities. The phylogenetic tree suggests that the retention of scales in the species pair of S. pingchowensis and S. macrolepis represents a rare case of evolutionary reversal from cave-adapted degeneration. This phenotypic re-emergence correlates with their re-colonization of surface water, likely reflecting a synergistic adaptation to both photic exposure and occupation of the niche of mid-upper water strata, coinciding with relaxed selection on cave-associated trade-offs. The divergence of S. pingchowensis from its sister species was likely triggered by the river capture event between the two rivers.

Understanding the relationship between the parasitism characteristics, development, and reproduction of parasitoids and host age is crucial for effective pest biocontrol. To optimize the biological control strategy of the potato tuber moth (PTM), Phthorimaea operculella, the parasitic behavior, host preference, offspring fitness, and glasshouse efficacy of a natural Trichogramma chilonis strain on PTM eggs of different ages were assessed. Trichogramma chilonis successfully parasitized PTM eggs aged 24-108 h, but behavioral acceptance rate decreases significantly with increasing age. Younger eggs (24 h) were examined more quickly, while drilling and oviposition times were unaffected by age. In choice tests, T. chilonis preferred eggs aged 72 h or less, with no significant preference found in no-choice tests. Notably, offspring fitness was significantly reduced when parasitizing older eggs (96 h). Compared to T. chilonis offspring obtained from parasitizing 72 h eggs, those developing from 96 h eggs exhibited a 58.69% decrease in emergence rate and a 21.97% reduction in fecundity. Furthermore, the offspring were also smaller in size. Female body length, head width, and hind tibia length decreased by 8.88%, 10.27%, and 12.97%, respectively, with corresponding reductions in males were 6.11%, 8.39%, and 5.24%. Glasshouse trials further confirmed that T. chilonis parasitizes PTM eggs on plants, reducing emergence of PTM adults by 47.78%. Trichogramma chilonis perform best on 24-72-h-old PTM eggs, and oviposition preference exhibits behavioral plasticity. This reveals the host-use pattern and oviposition strategy linked to offspring performance in T. chilonis, providing implications for its application in the biological control of PTM. © 2026 Society of Chemical Industry.

Similar developmental outcomes of salamander larvae produced with fresh and cryopreserved sperm: implications for amphibian conservation.

Cranial morphology assessed through anthropometric indices is fundamental for understanding population diversity, forensic identification, and clinical assessment, particularly within Nigeria’s multi-ethnic context. This cross-sectional study aimed to compare cephalic indices—defined as the ratio of maximum head breadth to maximum head length—between the Jhar and Sayawa ethnic groups in Tafawa-Balewa Local Government Area, Bauchi State, Nigeria, and to generate baseline reference data for these populations. A total of 410 participants (103 Jhar and 307 Sayawa), aged 5–66 years (mean = 24.0 ± 11.2; 291 males and 119 females), were recruited, and socio-demographic information was obtained using a structured pro forma. Head length and breadth were measured following standardized anthropometric techniques, and cephalic indices were calculated accordingly. Data were analyzed using Microsoft Excel and SPSS (Version 27), with descriptive statistics, charts, and tables for presentation, and categorical associations evaluated using Chi-square tests (p < 0.05). The mean cephalic index was 79.33 ± 4.85 for Jhar and 78.32 ± 5.19 for Sayawa, values that fall within the mesocephalic range indicative of intermediate head shapes typical of populations in the region. No statistically significant differences were observed between the two ethnic groups (p > 0.05), suggesting a broadly shared cranial profile. These findings enrich the anthropometric database for Nigerian ethnic groups and have practical implications for forensic anthropology, clinical assessment, and future research on craniofacial variation in multi-ethnic populations.

3D ultrasonic visualization of hip displacement: A phantom study.

Potential effects of bexarotene on neural development and function in zebrafish embryos.

Objective. To evaluate the influence of head morphology on the performance of a wearable setup that incorporates the constraints of an eyewear-electroencephalography (EEG) device suitable for consumer-level applications. Specifically, the study aimed to characterize the electrode-skin impedance of two dry-electrode types mounted on eyeglass frames, assess the system's ability to capture alpha-rhythm modulation during eyes-open and eyes-closed (EOEC) states in the temporal region, and its capability to detect auditory event-related potentials (P300).Approach. A prototype was built by embedding four EEG electrodes, two gold-plated retractile pins (GPR) and two conductive elastomer (CoE), into a commercial eyeglass frame, with reference and bias on the nose pads. Signals were acquired using an OpenBCI Cyton board (ADS1299 analog front end, sampling at 256 Hz). Twenty young healthy adults underwent three experimental protocols, namely electrode-skin contact assessment, EOEC tasks (two cycles of 2 min each) to examine alpha-band (8-12 Hz) power changes and compute an alpha-to-broadband power ratio, and an auditory oddball paradigm (80% standard, 20% odd stimuli, 50 odd trials) to elicit and analyze P300 components.Main results. GPR electrodes exhibited moderately higher median impedance but slightly narrower confidence intervals compared to CoE electrodes. Head breadth significantly affected GPR impedance (≈11.7%decrease per mm increase), but had no significant effect on CoE impedance. Alpha-band power increased significantly during eyes-closed periods across subjects and electrode types. P300 responses (positive deflection at 300 ms) were reliably detected, with GPR electrodes yielding tighter latency distributions.Significance. These findings emphasize the importance of careful design considerations in wearable-EEG to account for inter-subject head anatomy variability and demonstrate that eyeglass-integrated EEG, can reliably capture both evoked and spontaneous neural responses.

Based on morphological comparisons and molecular phylogenetic analyses, a new species of the genus Tylototriton from Wufeng County, Hubei Province, China, is described. Phylogenetic analyses of mitochondrial 16S rRNA and ND2 gene sequences supported the new species as an independent clade, sister to a clade containing Tylototriton dabienicus and T. gaowangjienensis . The uncorrected p-distances of the 16S rRNA and ND2 genes between the new species and its closest congeners were 0.7% and 1.7%, respectively. Divergence time estimates indicated separation from T. dabienicus and T. gaowangjienensis at 2.53 million years ago (Mya; 95% highest posterior density [HPD]: 1.53–3.72 Mya). Bayesian species delimitation (BFD and bPTP analyses) strongly supported the new taxon as a distinct species. Morphologically, it is distinguished by: (1) moderate body size (SVL 63.7–77.2 mm in males, 74.9–88.1 mm in females); (2) head width exceeding head length; (3) presence of a gular fold; (4) tail shorter than snout–vent length; (5) orange distal digits, cloacal periphery, and tail margin; (6) limb tips meeting when fore- and hindlimbs are pressed along the trunk; (7) fingertips extending beyond the snout when forelimbs are stretched forward; and (8) continuous, indistinct, nodule-like warts on the body sides.

Adult body size often varies geographically in response to local climatic conditions. The Emma field cricket ( Teleogryllus emma ) exhibits a reverse Bergmann’s rule pattern, with smaller adults occurring at higher latitudes. This trend was confirmed across populations sampled from 33°N to 41°N. One unique population inhabits the periodically exposed reservoir slopes (RS) of the Oishi Dam, Niigata, Japan. These crickets display significantly reduced body sizes compared to those in the surrounding grasslands. To investigate the underlying causes of this body size reduction, we examined the influence of environmental and genetic factors. Laboratory-reared mid-instar nymphs from the RS grew into larger adults than their field-collected counterparts, suggesting an environmental basis for reduced body size. High temperatures led to smaller adults, while high rearing densities (100 individuals per container) significantly reduced adult size compared to low densities (1–2 individuals). Photoperiod (11–16 hours) also influenced growth: longer daylengths extended development and produced larger adults. Small but significant size differences between the RS and surrounding populations suggest possible genetic differentiation, although further genetic analysis is needed to confirm evolutionary divergence. Delayed hatching at the RS exposes the crickets to shorter daylengths, likely accelerating growth and leading to smaller adults. Year-to-year variation in adult head width in the RS population primarily correlated with nymphal densities rather than temperature. Interestingly, smaller adults laid smaller eggs, yet nymphs from these eggs exhibited compensatory growth, often reaching sizes comparable to those from larger eggs, resulting in no significant correlation between adult body sizes of females and offspring. Overall, body size variation in T. emma at the RS appears to be shaped by both phenotypic plasticity in response to environmental conditions and genetic differentiation. Despite these fluctuations, body size in some populations has remained stable for over half a century, suggesting possible stabilizing selection or genetic constraints.

Sexual dimorphism (SD) is a widespread phenomenon among animals and has attracted considerable interest in evolutionary biology. Most studies on SD have been limited to a single population, and few have focused on multiple populations. In this study, size and shape SD were evaluated in three populations of Batrachuperus karlschmidti, a hynobiid species endemic to China. SD was not found in body size, but was observed in body shape. Males had larger relative dimensions in head length, head width, forelimb length, forelimb width, hindlimb length, hindlimb width, and tail length. Conversely, females were larger in the relative dimension of interlimb distance. Sexual selection can account for SD in head and limbs, thereby enhancing male reproductive success. Conversely, fecundity selection drives SD in limbs, tail length, and interlimb distance, ultimately improving the reproductive ability of both sexes. Differences in sexual shape dimorphism (SShD) traits were also found among populations, which may be caused by dissimilar levels of selection forces in the environment. This study provides insight into identifying the causes that promote sexual dimorphism, as well as the degree of difference in SShD traits among populations.

An assessment of morphometric characteristics and phase status was conducted on a natural population of the Asian migratory locust (Locusta migratoria migratoria L.) in the Slavyansky district of Krasnodar Krai, one of the key areas of its reservation. A sample of 201 adult individuals (114 males and 87 females) was analyzed. Four key morphometric parameters were measured: elytron length (E), hind femur length (F), pronotum length (P), and head width (C). Based on these measurements, classic phase indices (E/F, F/C, and P/C) were calculated to reflect the degree of gregariousness of individuals. Pronounced sexual dimorphism was established, with females being statistically significantly larger than males in all absolute measurements. Analysis of the phase indices revealed significant population heterogeneity. Based on the F/C ratio, the majority of individuals (approximately 60 %) exhibited characteristics of the solitary phase. In contrast, the E/F and P/C indices showed a mixed picture, with a predominance of solitary and transient phase individuals but with a substantial proportion (13-30 %) of individuals showing distinct gregarious phase traits. The comprehensive analysis indicates that the population is generally in a low-density state (predominantly solitary phase) but contains a significant pool of individuals with high potential for gregarization. These findings are critically important for the phytosanitary monitoring system, as they indicate persistent risks of mass outbreak formation in the region.

The Lesotho Merino sheep is a native Merino strain formed from the indigenous fat‐tailed sheep through crossbreeding over many generations. This study is aimed at phenotypically characterizing Merino sheep locally bred in four agro‐ecological zones of Lesotho, facilitating easy selection based on morphological traits. Body weight (BW), body length (BL), withers height (WH), rump height (RH), chest girth (CG), rump length (RL) and rump width (RW) were measured in 2515 mature shorn Merino ewes from four agro‐ecological zones: mountains (n = 1554), the Senqu River Valley (n = 350), lowlands (n = 395) and foothills (n = 216). A multivariate discriminant analysis procedure identified and quantified the traits that differentiate the Merino sheep across these agro‐ecological zones. The structure matrix indicated that RL had the highest loading (0.82) in Function 1, whereas WH (0.6) and head width (0.36) exhibited the highest loadings in Functions 2 and 3, respectively. The standardized canonical discriminant coefficients showed that RL (1.02) and RW (0.60) were the highest in Function 1, whereas CG (0.65) and RH (0.41) were in Function 2, and WH (1.61) and RW (0.41) were in Function 3. The Mahalanobis distance was highest between the lowlands and the Senqu River Valley (3.46) and lowest between the mountains and foothills (0.61). Principal component analysis (PCA) extracted three components per agro‐ecological zone. Morphological traits differentiate Merino sheep across the agro‐ecological zones, suggesting the presence of two strains: one suited for the mountains, the Senqu River Valley, and foothills and another suited for the lowlands.

Avermectin and cyclobutrifluram cause oxidative stress and energy metabolic disorders of Caenorhabditis elegans.

Ethnicity, gender, age, environment and genes of a people, plays an important role in determining their craniofacial dimensions. This study was carried out to determine the mean values for the Height, Weight, Head length, Head width, Head height, Head circumference, Body mass index, Cephalic index, cranial capacity, Brain weight and Brain index of the Igbo students in University of Port Harcourt. The study also seeks to determine if there are sexual dimorphism and correlation between the cranial capacity and Head width.378 Igbo Students participated in the study (182 males and 196 females) between the age of 18-40 years. The mean and standard deviation values of the male Igbos for age, Height, Weight, Head length, Head width, Head height, Head circumference, BMI, Cephalic index, cranial capacity and Brain weight were: 27.22±7.65, 173.78 ±8.66cm, 65.49±10.16 kg, 18.01±0.89 cm, 14.3±0.95cm, 14.41±0.88cm, 56.71±2.55cm, 21.73±3.44kg/m2, 79.93±6.60%, 1412.7±111.1, 1462.2±115.0g and 2.29±0.39 while that of female Igbos were 25.83±5.65 , 167.32±9.17 cm, 60.73 ±11.11 kg, 17.68 ±0.76 cm, 14.07 ±0.76 cm, 13.97 ±1.05 cm, 56.3±31.74cm, 21.75±3.93kg/m2, 79.71±5.61%, 1313.8±128.8, 1359.8±133.3g and 2.31±0.45 respectively. It was observed that, the males had a significantly higher value than that of the females in the Height, Weight, Head length, Head width, Head height, cranial capacity and Brain weight (P<0.05). It was also observed that, there were no significant difference between the male and female values in the Head circumference, BMI and Cephalic index (P>0.05). The result in the present study showed a strong positive correlation between Igbo male Cranial Capacity and Head width(P<0.05). A linear regression equation for estimating cranial capacity from Head width for the Igbo students was established. The data will be useful to the Anatomist, anthropologist and the forensic scientist.

Body size is an important biological concept as it impacts nearly all aspects of an organism. In mainland systems, body size tends to show clinal variation; however, drastic body size shifts are typically limited to insular systems in correspondence with abrupt changes in climate patterns and resource availability, often in coordination with reduced genetic diversity. We investigate a rare occurrence of dwarfism and its influence on sexual size dimorphism (SSD) among two mainland species inhabiting the San Luis Valley (Valley) using museum and live specimens. The Valley population of the greater short-horned lizard (Phrynosoma hernandesi) is 33.7% smaller and the Valley population of the Great Plains toad (Anaxyrus cognatus) is 32.9% smaller than populations surrounding the Valley (Outside). The greater short-horned lizard exhibits female-biased SSD range wide, and female-biased SSD among Valley populations is maintained for head length and width but is inconsistent among test groups for radius, hand, and femur length. In the Great Plains toad, SSD is absent among museum specimens from the Outside population and live specimens the Valley population, but shows a weak presence in parotoid gland morphology among museum specimens from the Valley. Although the mechanisms underlying dwarfism and possible selective pressures associated with shifts in female-biased SSD are unknown, we present a rare instance of mainland dwarfism and its influence on SSD.

This study aimed to identify the morphological characteristics and fetometric parameters of Bali cattle fetuses obtained from the Municipal Abattoir (RPH) of Ambon, and to examine the relationship between Crown–Rump Length (CRL) and gestational age. Thirty fetus samples were collected and measured using a measuring tape and a digital scale. Observed fetometric parameters included CRL, head length, head width, head circumference, and fetal body weight. Data were analyzed descriptively to determine the relationship between fetometric size and gestational age. Results showed that fetal morphology developed consistently with increasing CRL. At CRL 21–31 cm (±90–120 days), skin pigmentation and tactile hair appeared; CRL 32–44 cm (±120–150 days) indicated external genital development; CRL 45–56 cm (±150–180 days) showed hair growth on the tail and ears; and CRL 57–70 cm (±180–210 days) exhibited morphology similar to newborn calves. The relationship between CRL and gestational age followed a non-linear pattern consistent with physiological fetal growth. It was concluded that CRL and fetal weight serve as reliable indicators for estimating gestational age in Bali cattle. The fetometry-based prediction model developed in this study could be applied as a practical tool in field or abattoir conditions, although further validation with larger and more diverse samples is recommended.

Bite force is a simple trait indicating an animal’s performance related to foraging, social dominance, and defence, all of which influence individual reproductive success. We examine the effect of breeding status on bite force in four social species of Fukomys, a genus of subterranean African rodents (Bathyergidae). These species are cooperative breeders, where reproduction is limited typically to a breeding pair. We collected in vivo bite force data, head width, and upper incisors width from 404 individuals from 75 families and tested whether breeders exhibit stronger bite force. We reveal that breeding males of all four species outperform non-breeders, with bite force in non-breeding males and females being 12% and 22% lower, respectively. In contrast, breeding females underperform relative to other categories, with bite force approximately 31% lower than in breeding males, and many are reluctant to bite. Head width and upper incisors width corroborate these findings. We propose that breeding males require a stronger bite force because of repeated competition with non-related males that may try to enter the family. In contrast, there is much less competition for the breeding position among females, as females rarely intrude into established families.

Abstract This study employed an orthogonal experimental design, coupled with range and variance analysis, to investigate the sensitivity of the flow and heat transfer performance in a microchannel heat exchanger to header structural parameters. The results show that the degree of influence on the flow and heat transfer performance follows the order: the diameter of the inlet and outlet tubes, the lateral distance between the inlet and outlet tubes, and the header width. Increasing the diameter of the inlet and outlet tubes significantly improves the uniformity of fluid distribution and heat transfer coefficient, thereby enhancing total heat exchange capacity while reducing pressure drop. In contrast, increasing the lateral distance between inlet and outlet tubes reduces fluid distribution non-uniformity but increases heat transfer non-uniformity. Variations in the header width have a relatively minor impact on both the flow and heat transfer performance and their distribution uniformity. In the design of microchannel heat exchangers, the header width should be maintained at a relatively small value.

The product of head height and head width is a strong predictor of brain mass in birds

The study of common and widely distributed species can help us understand how their ecology and natural history may vary across their range and respond to local ecological factors. Here, we studied the ecological and natural history aspects of the lizard Tropidurus hispidus at Estação Ecológica de Aiuaba, an Integral Protection Conservation Unit, in an area of ​​Caatinga, state of Ceará, Northeastern Brazil. Our objective was to analyze the diet, foraging, sexual dimorphism, reproductive biology and helminthofauna associated with T. hispidus. We collected the specimens between the years 2012 and 2015 through active search, time-limited visual search, and pitfall traps. Overall, we collected 103 specimens of T. hispidus. There was sexual dimorphism, with males showing greater head and body width. Reproduction occurred between the middle of the dry season and the beginning of the rainy season. The diet was composed of 18 categories of food items, consisting mainly of ants, in addition to important amounts of plant material. The helminthofauna was composed of ten taxa, with the first occurrence of Oochoristica travassosi and O. vanzolinii infecting Tropidurus hispidus. Despite being a generalist species and one of the most common in the Neotropics, here, we present some unprecedented information about the ecology and natural history of Tropidurus hispidus, and we compared our results with data from other populations in the Caatinga.