Head Depth Research Articles

Flow and depositional response of turbidity currents to complex canyon topographies: A numerical simulation perspective

Submarine canyons are prominent features on continental margins, acting as major conduits for sediment transport primarily through turbidity currents. Understanding how these currents interact with complex canyon topographies is crucial for deciphering the canyon system evolution, yet challenging due to limited field observations. Focusing on a group of slope-confined canyons within the Pearl River Mouth Basin, northern South China Sea, this study integrates multibeam bathymetry, core analysis, and process-based Computational Fluid Dynamics (CFD) modeling to investigate the influence of realistic canyon topography on turbidity current dynamics and resulting sediment deposition. Analysis of core samples revealed a potential turbidite layer characterized by silts and sandy silts. Using these sediment information and bathymetric data, we conducted a series of three-dimensional CFD simulations. Our findings highlight the significant variability in turbidity current characteristics, particularly flow velocity and sediment concentration, within the canyon groups. This variability is primarily controlled by canyon head depth, the width-to-relief ratio, and slope gradients. Notably, the simulations revealed unique flow structures not typically observed in experimental settings, including unidirectional flows, small-scale helical flows, stacked and mixed flow cells, and flow separation and convergence across inter-canyon ridges. Our CFD simulations also revealed a distinct near-wall pattern of linear deposition of coarse-grained sediments, which is similar to the observed bathymetric changes between 2009 and 2017. Based on the consistent results, we propose a conceptual model wherein differential erosion, driven by oceanographic processes, plays a key role in shaping the observed linear depositional patterns.

Phenotypic covariation predicts diversification in an adaptive radiation of pupfishes.

Phenotypic covariation among suites of traits may constrain or promote diversification both within and between species, yet few studies have empirically tested this relationship. In this study, we investigate whether phenotypic covariation of craniofacial traits is associated with diversification in an adaptive radiation of pupfishes found only on San Salvador Island, Bahamas (SSI). The radiation includes generalist, durophagous, and lepidophagous species. We compared phenotypic variation and covariation (i.e., the P matrix) between (1) allopatric populations of generalist pupfish from neighboring islands and estuaries in the Caribbean, (2) SSI pupfish allopatric lake populations with only generalist pupfish, and (3) SSI lake populations containing the full radiation in sympatry. Additionally, we examine patterns observed in the P matrices of two independent lab-reared F2 hybrid crosses of the two most morphologically distinct members of the radiation to make inferences about the underlying mechanisms contributing to the variation in craniofacial traits in SSI pupfishes. We found that the P matrix of SSI allopatric generalist populations exhibited higher levels of mean trait correlation, constraints, and integration with simultaneously lower levels of flexibility compared to allopatric generalist populations on other Caribbean islands and sympatric populations of all three species on SSI. We also document that while many craniofacial traits appear to result from additive genetic effects, variation in key traits such as head depth, maxilla length, and lower jaw length may be produced via non-additive genetic mechanisms. Ultimately, this study suggests that differences in phenotypic covariation significantly contribute to producing and maintaining organismal diversity.

New species of Batrochoglanis Gill (Siluriformes: Pseudopimelodidae) from the Capim River basin, State of Pará, Brazil

Batrochoglanis labrosus new species, is described from the Capim River Basin, State of Pará, Brazil. The new species differs from congeners by the stout, inferior mandible, hypertrophied lips on the lateral of the mouth, a broad dark brown band extending dorsoventrally from the beginning of the trunk to the posterior third of the adipose fin followed by a second dark brown band on the caudal peduncle, dark brown pelvic fin, and caudal fin hyaline with a concentration of dark brown spots on the posterior margin, sometimes forming an irregular band. The morphometric variables of B. labrosus are similar in B. villosus and B. castaneus, forming a B. villosus species group. The B. villosus group is distinct from other group formed by B. acanthochiroides and B. transmontanus in the third axis of the Principal Components Analysis. The variables with higher positive loadings in the B. villosus group, representing larger measurements, were adipose-fin base length, eye diameter, maxillary barbel length, head depth, and mouth width; the higher negative loadings representing shorter measurements were pelvic fin to anal fin distance and pectoral-fin spine length. The species is known only from the Capim River basin, where it is possibly endemic.

Ecological opportunity leads to higher diversity and probability of trophic specialization in Arctic charr

Abstract Understanding the extrinsic factors that drive the emergence of biological diversity is critical to its protection and management. However, even superficially similar local environments can vary considerably, and so large-scale datasets are needed to understand the key drivers across a representative portion of a species distribution. Arctic charr (Salvelinus alpinus) is a widespread salmonid fish that represents an excellent study system for these processes because the species shows substantial diversification to a range of freshwater environments and multiple instances of trophic specialization in the form of sympatric ecotype populations. However, the processes behind this variation remain largely unknown due to a lack of broad-scale studies. To address this, we investigated the drivers of diversity via a national-scale study of 64 Arctic charr populations in lakes across Scotland using a genome-wide dataset of single nucleotide polymorphisms (N = 24 878) and phenotypic data of head depth relative to body size. We found that the extent of genetic and phenotypic diversity was predicted by ecosystem size (a proxy of lake size, depth, and complexity). We suggest this is because larger, deeper lakes generally provided more ecological opportunity and diversification potential. Additionally, using environmental data from all 187 lakes containing Arctic charr in Scotland, we found that ecosystem size strongly predicted the potential for trophic specialization and the presence of sympatric divergent ecotypes. Our results show the importance of ecological opportunity in underlying adaptive radiations.

Research on Underground Drip Irrigation and Soil Redistribution - Take Heshan District of Yiyang City as an Example

Abstract: The drip flow and the buried depth of drip irrigation zone are not only important parameters of subsurface irrigation design and operation management, but also important factors affecting the migration and redistribution of soil water and fertilizer. Crop growth is closely related to soil water and nitrogen leaching, water and fertilizer transport patterns and redistribution characteristics. It is of great significance to study the migration and redistribution of soil water and fertilizer under subsurface drip irrigation for improving the utilization efficiency of water and fertilizer and improving the system of subsurface drip irrigation. In this paper, the migration mode and redistribution characteristics of water and nitrogen in subsurface drip irrigation were studied and analyzed by means of laboratory soil box experiment, considering the two factors of drip flow and the buried depth of drip irrigation belt. The main research conclusions are as follows: Ⅰ. Different drip flows had effects on soil moisture front, soil moisture content and soil water redistribution. If other conditions remain unchanged, increasing the drip flow can increase the moist body area of soil and increase the moisture content of soil. The distance between vertical and horizontal directions increased with the large drip flow, and the soil water content decreased with the increase of distance. Large drip flow can promote the redistribution of soil water after drip irrigation. Ⅱ. Different drip depth had effects on soil moisture content and soil water redistribution. When the drip depth was 0cm, the surface shape of the wet body was a "horizontal" semi-ellipse after drip irrigation. When the drip depth was 10cm and 20cm, the surface of the wet body was an "upright" semi-ellipse after drip irrigation. The larger the buried depth of the drip can make the distribution of soil moisture more uniform, and the larger the buried depth of the drip can promote the migration of water in the soil. Ⅲ. Different drip discharge had an effect on soil nitrogen redistribution, and large drip discharge promoted soil nitrogen redistribution after drip irrigation. The Nitrate Nitrogen (NO3--N) content in the moist body is lower than that near the edge of the wetting front. The content of Ammonium Nitrogen (NH4+-N) near the edge of the wetting peak is higher than that inside the wetting body. Ⅳ. The redistribution of soil nitrogen was affected by different buried depth of drip head, and the greater buried depth of drip head could promote the redistribution of soil nitrogen. In terms of vertical and horizontal migration of ammonium nitrogen and nitrate nitrogen, on the day after drip irrigation, the cumulative effect of Nitrate Nitrogen (NO3--N) buried at a depth of 20cm was more significant near the wetting front edge at a larger vertical downward distance, and the cumulative effect of Nitrate Nitrogen (NO3--N) buried at a depth of 20cm was more significant inside the wetting body at a larger vertical downward distance. At the same time, the drip buried depth of 20cm can spread the cumulative effect inside the wet body and near the edge of the wet front to a longer horizontal distance.

A new scaled testing methodology for the analysis of rolling contact fatigue in railway steels.

Twin disc testing is a relatively cost effective and practical method of investigating the damage resistive properties of rail steels in a scaled environment. The loading conditions and dimensions used in testing are scaled in such a way that the Rolling Contact Fatigue (RCF) generated on a twin disc rig are representative of the conditions experienced at the full-scale. Typical methodologies to generate RCF on a twin disc rig involve the application of water to the contact patch throughout the test, with perhaps a few thousand dry cycles being run beforehand. This research explores the use of weather data to reflect the real-world contact conditions more accurately between a wheel and rail. Met Office weather data collected from 1981 to 2010 shows the average annual precipitation in the UK is around 133 days of rain or snow, which is nearly 36 % of the year. In this study, weather data was used to determine the ratio of wet to dry cycles in the testing methodology.  50k dry cycles are run in intervals of 5k and then transitioned to 25k of wet cycles, which is 30% of the total cycles. Intervals were kept at 5k so attaining 36%. If RCF is not initiated after the first 75k cycles, which ends with 25k wet cycles, then the same dry and wet cycles are repeated. RCF data generated using this methodology demonstrated expected differences in the RCF resistive properties of two rail steel grades, R260 and R350HT. In test 1 the point of initiation for each grade was not captured, though cracks were visible around the expected cycles to initiation, which was verified using optical microscopy. The cracks viewed on the softer R260 steel samples, ‘’260’’ referring to the Brinell hardness value of the steel, were more developed at 85k cycles and showed signs of spalling, whilst the cracks on the harder R350HT sample were much smaller. In test 2 the point of initiation was found for each grade. Optical microscopy was also used to show the depth and direction of head check cracks to ensure the damage viewed from the head was RCF and not plastic flow or cyclic wear. This paper shows the necessity for considering the number of wet cycles applied during twin disc testing and demonstrates it is possible to run a high number of wet cycles which are more representative of real-world conditions when generating RCF on twin disc rigs.  

The effect of delayed first feeding on growth and survival of yellowfin seabream (Acanthopagrus arabicus) larvae

The effect of different initial feeding times (48 h, 72 h, 96 h, and 120 h after hatching) and food deprivation on the point-of-no-return (PNR), survival, and growth of yellowfin seabream Acanthopagrus arabicus larvae were studied under controlled condition. Growth parameters were investigated by evaluating morphometric (head depth, body depth, gut height, musculature height, eye diameter, total length, yolk, and oil globule volume) and gravimetric (dry weight) indices. The larvae commenced to feed exogenously at the mouth opening stage on day 2 after hatching (DAH) and reached PNR between 6 and 7 DAH at 19–20 °C. The time of initial feeding significantly affected the larval growth. From 3 DAH until the end of the trial period at 15 DAH, the growth (all morphometric indices and dry weight) of larvae started which earlier initial feeding start (48 h and 72 h after hatching) were significantly higher than that of 96 h (P < 0.05). Growth parameters were measured until 9 DAH in the larvae commenced feeding at 120 h, since complete mortality was recorded after this sampling point (at 12 DAH). During this period, the larvae showed significantly lower morphometric indices and dry weight compared with larvae in other initial feeding time treatments (48 h, 72 h, and 96 h). Yolk absorption in yellowfin seabream larvae was completed on 4 DAH regardless of the variances in the time of first feeding. Likewise, the oil globule was completely utilized on 5 DAH in all initial feeding trials. No significant differences were noticed in yolk volume and oil globule absorption between different treatments. At the end of the trial at 15 DAH, the survival rate was significantly higher for larvae began first feeding at 48 h (35.67 ± 7.01%) and 72 h (36.48 ± 4.72%) when compared to 96 h first feeding larvae (13.10 ± 2.62%)(P < 0.05). The findings from the current study reveal that the first feeding of yellowfin seabream larvae can be initiated up to 72 h after hatching with no significant differences in growth and survival rate.

Stock Identification of Short Mackerel (Rastrelliger brachysoma) in the Upper and Middle Gulf of Thailand by Morphological Characters

Rastrelliger brachysoma, a short mackerel, is a significant pelagic fish that is common in the fisheries in the Gulf of Thailand. The management of fish stocks is a prerequisite for fish conservation strategies and profitable fisheries. Morphological character differences between stocks of species provide a method for identifying fish stocks. This study was aimed to identify stock population of short mackerel in the Upper and Middle Gulf of Thailand. The fish specimens were collected from four different locations: Chonburi and Prachuap Khiri Khan (central provinces of Thailand), Chumphon and Surat Thani (southern provinces of Thailand). Twelve morphometric characters of fish were assessed to determine the stock populations by stepwise discriminant analysis. The results showed that 12 morphometric characters were significantly different among the four populations. In the discriminant function analysis, the first function explained 61.30% of total variations, whereas the 2nd and 3rd functions were 26.50% and 12.20%, respectively. The characters included total length, standard length, folk length, head length, post – orbital length, pre – dorsal length, pre – pelvic length, 1st dorsal to 2nd dorsal length, pelvic to anal length, pre – anal length, head depth, and greatest depth, all of which can be used to differentiate these populations. According to the results of the discriminant analysis, the populations of short mackerel were predicted and subsequently classified with an accuracy rate of 54.88%.

Comparative analysis of morphological characteristics, hematological parameters, body composition and sensory evaluation in olive flounder, Paralichthys olivaceus raised in biofloc and seawater to evaluate marketability

This study evaluated the productivity on the market of olive flounder, Paralichthys olivaceus, raised in biofloc. The marketability evaluation was measured by morphology, body composition, hematological parameters, and sensory evaluation in P. olivaceus (biofloc fish; mean weight 1142 ± 260 g, mean length 43.40 ± 2.9 cm, and control fish; mean weight 1121 ± 173 g, mean length 44.60 ± 1.8 cm) raised in biofloc for 8 months. Morphologically, P. olivaceus raised in biofloc showed a significant decrease in head depth and head depth-head length ratio (P < 0.05). Hematological parameters (hematocrit and hemoglobin) and plasma components (calcium, magnesium, glucose, cholesterol, and alanine aminotransferase) were not significantly different between P. olivaceus raised in the biofloc and the control. No significant differences were discovered in the proximate composition (moisture, crude protein, crude fat, crude fiber, and ash) of P. olivaceus raised in the biofloc compared with the control group. In amino acid composition, valine and isoleucine in P. olivaceus raised in biofloc were significantly higher than in the control group (P < 0.05). The saturated fatty acids (capric acid and palmitic acid) in P. olivaceus raised in the biofloc were significantly increased (P < 0.05). The unsaturated fatty acids (linoleic acid and dihomo-γ-linoleic acid) in P. olivaceus raised in the biofloc were significantly decreased (P < 0.05); however, docosahexaenoic acid was significantly increased (P < 0.05). No significant differences were noted in other sensory evaluations, including fishy odor, chewiness, moisture, viscosity, elasticity, hardness, meaty gloss, meat-colored transparency, smell, flavor, texture, and appearance. However, the comprehensive preference of P. olivaceus raised in biofloc was significantly increased (P < 0.05). This study showed that fish products of P. olivaceus raised in a biofloc system had approximately the same nutritional value as commercial fish products of P. olivaceus, suggesting a marketability potential as food.

Sexual dimorphism and reproductive biology of Cephalocassis borneensis (Siluriformes: Ariidae), a paternal mouth-brooding fish in the Mekong River.

Information on the reproductive biology of fish species is essential for fisheries management, conservation and culture potential assessment. Therefore, this study aimed to understand the sex-based morphological differences and reproductive characteristics of Cephalocassis borneensis, an ariid species with a rapid decline of wild populations. Fish samples were collected monthly from local fishermen (n = 1092) in the Vietnamese Mekong River over a year. Morphological analyses revealed that sexual dimorphism was observed in mature, but not immature, fish. The length at first maturity (Lm ) was smaller for males (11.5 cm) than for females (12.5 cm). Mature males had larger head length and pre-pectoral distance than mature females, increasing the space for oral incubation of fertilized eggs and larvae in males. Conversely, females were larger in three head parameters (head angle, head width and head depth) and three abdomen parameters (body deep, ventral fin length and distance between pectoral and ventral fin) involved in ovary development. Paternal mouth-brooding behaviour is an important reproductive strategy in C. borneensis to increase offspring survival. Monthly variations in gonado-somatic index and condition factor (K) and the presence of maturation stages indicated that C. borneensis spawns year-round, mainly in the rainy season from June to October. This species' fecundity was relatively low, from 10 to 31 eggs per female of quite large sizes (about 7.30 ± 0.68 mm in diameter). Besides, non-functional oocytes (hyaline eggs) of smaller size (<3 mm) were found in the females' ovaries. Low fecundity with large eggs and paternal care indicated that the species is an equilibrium strategist. These characteristics are critical in developing ariid species conservation plans, such as setting the time and mesh-size for fishing, and domestication programmes in artificial conditions.

Allometric Growth Patterns and Ontogenetic Development during Early Larval Stages of Schizothorax waltoni Regan and Percocypris retrodorslis in Southwest China

Due to a sharp decline in resources, Schizothorax waltoni Regan and Percocypris retrodorslis have been listed as wildlife under second-class protection in China. Under culture conditions, the early development and allometric growth patterns of S. waltoni and P. retrodorslis were researched from the hatching stage to 60 DPHs (days post-hatching), and a sampling of ten to fifteen larvae was made every day, followed by measurements with Axio Vision 4.8 software (Carl Zeiss AG, Jena, Germany). Morphological indicators included the anal fin length, the body depth, the body depth at the anus level, the caudal fin length, the dorsal fin length, the eye diameter, the head length, the head depth, the pectoral fin length, the tail length, the trunk length, the snout length, the total length, and the ventral fin length. Based on the morphology development of S. waltoni Regan and P. retrodorslis, four periods of larval growth were identified: pre-flexion larvae at 0–14 DPHs and 0–16 DPHs; flexion larvae at 14–23 DPHs and 16–26 DPHs, post-flexion larvae at 23–50 DPHs and 26–52 DPHs, and the juvenile stage. In newly hatched larvae, most organs and body parts were not differentiated, and they successively developed within 26 DPHs. The depletion of the yolk sac was observed at 23 DPHs and 25 DPHs. Allometric growth mainly occurs in the head and tail regions, indicating that body parts related to feeding and swimming behaviors were more important than the other parts. In addition, the growth pattern shows that the development of organs gives priority to the functions of gill respiration, sensation, exogenous feeding, and swimming. The inflection points of body part growth patterns only appeared before 40 DAH, so future studies should concentrate focus on developing the best feeding from the first feeding to 40 DAH. These outcomes were discussed with regard to the ontogeny of the functional morphology in relation to ecology and aquaculture. It is expected that this research can provide valuable perspectives in species conservation.

Biological and morphological aspects of spiny eel Mastacembelus mastacembelus (Banks and Solander, 1794) inhabiting Al-Tharthar canal / Samarra, Iraq

Biological aspects (size composition, length-weight relationship, condition factor, food habit and reproduction season), and morphological of Mastacembelus mastacembelus inhabiting Al-Tharthar canal studied during the period from April to September 2012. The growth pattern was negative allometric with (b) values for males 2.680, females 2.845 and for combined sexes 2.597. Condition factor values were lower than one, ranged from 0.183 to 0.432 with average 0.282 ±0.053 for combined sexes. Food items from stomach collected and analyzed using both points and frequency methods. Two food items found only in the diet. M. mastacembelus is a predator, the males preferring fish while the females preferring fish and crustacean (prawns). The research cover, the ratios each of sixteen morphometric measurements to standard length, and each of four morphometric measurements to head length and their linear regression equations. All the length-length relationships between standard length and the others measurements were highly correlated except head depth, body depth and body width, and for head length, head depth only.&#x0D; &#x0D;

Phototoxicity of temoporfin-loaded cyclodextrin nanosponges in stroma-rich three-dimensional models of head and neck cancer

Photodynamic therapy is a multistage treatment, in which cancerous and precancerous cells are destroyed by light activation of a drug (photosensitizer). For a long time, high cellular uptake of the photosensitizer was an important indication of efficient PDT, while the role of photosensitizer penetration was unexplored. Recently, we have demonstrated that nanosponges based on hypercrosslinked β-cyclodextrin polymer (β-CDp) can increase drug penetration at the cost of their cellular uptake in multicellular spheroids, paving the way for studying the impact of penetration on PDT response.In the present work, we used β-CDp nanosponges to deliver temoporfin to the depth of stroma-rich head and neck cancer multicellular spheroids and then assess PDT response. Encapsulation of temoporfin in β-CDp nanosponges resulted in increased penetration and more uniform distribution of temoporfin in spheroids, however, was also associated with a two-fold reduction of cellular uptake compared to the free drug. Nevertheless, we demonstrated that β-CDp nanosponges possess similar PDT efficiency as the free drug in stroma-rich head and neck cancer multicellular spheroids. Overall, this study suggests that β-CDp nanosponges are a strong candidate for in vivo studies as they have fewer “off-target” effects while providing a similar therapeutic response.

Additional Data on Arctozenus australis Ho et Duhamel, 2019 (Pisces: Aulopiformes, Paralepididae) off Kerguelen Islands

This work clarifies the morphological data for the recently described species Arctozenus australis Ho et Duhamel, 2019. Specimens caught in the northwest of the known range of the species confirm the validity of diagnostic characters and expand the known range of the following parameters: predorsal length, prepelvic length, preanal length, distance between origins of dorsal and anal fins, head depth, distance between origins of dorsal and pelvic fins, interorbital width, caudal-peduncle depth, snout length, upper-jaw length, lower jaw, number of caudal vertebrae, preanal vertebrae, and anal fin rays.

Morphometric characters of the whitefish ludoga (coregonus lavaretus ludoga) in connection with the lake Issyk-Kul ecological and geographical conditions and its introduction

This article considers the influence of ecological and geographical conditions in the sequent whitefish ludoga (Coregonus lavaretus ludoga) relocation from Lake Ladoga to Lake Sevan and then from Lake Sevan to Lake Issyk-Kul. Morphometric studies of whitefish ludoga from Lake Issyk-Kul and a comparative analysis with similar data of this fish species of Lake Ladoga and Lake Sevan were carried out, taking into account the ecological and geographical condition of these lakes. In the course of our research, we found that the morphometric characters of whitefish ludoga during the introduction from Lake Ladoga to Lake Sevan and then to Lake Issyk-Kul changed due to the ecological and geographical conditions of these lakes. We have identified changes that occurred sequentially when moving from the plain region lake (Ladoga) to the mountain lake (Sevan) and to the mountain lake with brackish water (Issyk-Kul). These changes were mainly in the quantitative increase of some morphological parameters of these fish, such as raker counts on first branchial arch; scale counts on the lateral line; snout length and lower jaw length; predorsal distance and caudal peduncle length; head depth. In addition, there are changes characteristic of the Issyk-Kul fish, it is an increase in body depth and the dorsal fin height.

Changes in the condylar head after orthognathic surgery in Class III patients: a retrospective three-dimensional study.

To evaluate the axial and dimensional changes of the condylar head after orthognathic surgery, including Le Fort I and bilateral sagittal split ramus osteotomies, and to assess condylar remodeling through three-dimensional (3D) surface superimposition. Twenty-four patients (15 females, 9 males; mean age: 32.22 ± 6.92 years) with skeletal Class III deformity were included in the study. Cone-beam computed tomography data obtained in the preoperative (T0) and postoperative (T1) periods were examined using Mimics and 3-Matic software. The height, depth, and width of the condylar head and its angular changes were measured. The volumes of the 3D reconstructed models were calculated, and remodeling amounts were evaluated through regional surface superimposition. Statistical significance was set at P < .05. Following the surgery, there was a significant decrease in the size of condyles (P < .05). An inward rotation of the condyles was found in the axial plane (T0: 79.60 ± 6.01°, T1: 76.6 ± 6.48°, P < .05). The maximum resorption, maximum apposition, mean remodeling, and mean absolute remodeling were -2.63 ± 1.23 mm, 1.15 ± 0.4 mm, -0.30 ± 0.34 mm, and 0.73 ± 0.43 mm, respectively. No correlation was found between the angular changes and remodeling parameters or linear and volumetric changes of the condylar head (P > .05). Condyles undergo a remodeling process with a resorptive character following orthognathic surgery, without clinically significant effects in the present study.

Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil

The genus Rineloricaria comprises 69 valid species and has been considered monophyletic by some authors. The taxonomic history of Rineloricaria is quite complex, especially concerning its wide distribution and morphological plasticity that make it difficult to diagnose and describe new species. Even with the great species-richness of the genus and the huge diversity of the system, the Tocantins-Araguaia River basin hosts only three formally described species of Rineloricaria: R. hasemani, R. lanceolata, and R. osvaldoi, the former is known from lower Tocantins River, R. lanceolata widespread along Amazon basin and the last one restricts to the Araguaia River basin. Recent field expeditions and collection examination revealed an undescribed species of the genus from the upper and middle Tocantins River drainage. The new species is diagnosed among its congeners by having a greater number of premaxillary and dentary teeth (both with up to 15 vs. up to 10 in most congeners). From R. hasemani it is also distinguished by having the edge of snout straight in lateral view and absence of filaments on lower lip. It is also diagnosed from R. lanceolata by having wider cleithral width and a quite different color pattern, lacking a hyalin spot on the base of pectoral and pelvic fins; and from R. osvaldoi by having a lower head depth, triangular head in dorsal view, shorter snout length and other features.

FishShapes v1: Functionally relevant measurements of teleost shape and size on three dimensions.

Teleost fishes account for 96% of all fish species and exhibit a spectacular variety of body forms. Teleost lineages range from deep bodied to elongate (e.g., eels, needlefish), laterally compressed (e.g., ribbonfish) to globular (e.g., pufferfish), and include uniquely shaped lineages such as seahorses, flatfishes, and ocean sunfishes. Adaptive body shape convergence within fishes has long been hypothesized but the nature of the relationships between fish form and ecological and environmental variables remain largely unknown at the macroevolutionary scale. To facilitate the investigation of the interacting factors influencing teleost body shape evolution we measured eight functionally relevant linear traits on adult-sized specimens along with specimen mass. Linear measurements of standard length, maximum body depth, maximum fish width, lower jaw length, mouth width, head depth, minimum caudal peduncle depth, and minimum caudal peduncle width were taken in millimeters with calipers, or tape measures for oversized specimens. We measured these traits on a total of 16,523 specimens (1-3 specimens per species) at the Smithsonian National Museum of Natural History and took approximately 7000 person hours of data collection to complete. The data went through a three-step error-checking process to clean and validate the data and then species averages were calculated. We present the complete specimen data set, which encompasses approximately one-fifth of extant teleost species diversity, spanning ~90% of teleost families and ~96% of orders. The species and family names are compatible with the taxonomy used by FishBase and the order information with the phylogenetically informed taxonomy of Betancur-R and colleagues published in 2014. This dataset is licensed under Creative Commons CC0 1.0 Universal (CC0 1.0) but please cite this paper when using the data or a subset of it.

A new cryptic species of the pineapple fish genus Monocentris (Family Monocentridae) from the western Pacific Ocean, with redescription of M. japonica (Houttuyn, 1782)

A new pineapple fish is described based on 26 type and 80 non-type specimens collected from Taiwan, Vanuatu, the Solomon Islands, and Queensland, Australia. This new species is sympatric with and similar to Monocentris japonica but can be distinguished from the latter in having only 6 or 7 scales on the third scale row below the lateral line; excisura notched and a small pseudo-excisura present on the sagittal otolith; consistently greater head depth, body depth, postorbital length, dorsal-fin-pelvic-fin length, and dorsal-fin-pectoral-fin length in proportion to standard length. A detailed description and designation of neotype are provided for M. japonica. DNA barcoding analysis supports the distinction of the new species with an estimated average COI gene divergence of 3.6 % from M. japonica.

Numerical Simulation of Multifunctional Projectile Penetrating Reinforced Concrete Target Plate Based on Sensor Data Acquisition

The main material of a type of multifunctional warhead is energy-containing material, which mainly relies on the projectile’s own kinetic energy to hit the target plate to achieve the function of penetrating reinforced concrete, so it needs the bullet material to have high strength and be able to withstand the high overload when penetrating reinforced concrete. At present, the composite energy-containing material structure with Al, Zr, Ti, and other materials as PTFE-based reducing agents is the mainstream direction of research on high-strength energy-containing materials. LS-DYNA is used to establish a simulation model to simulate and analyze the tapping power. The relationship curve between material strength and attack depth is established and compared with the experimental data of traditional steel material attack ammunition to finally determine the strength limit of energy-containing material compared with traditional attack ammunition. The simulation results show that the composite energy-containing material multifunctional projectile can accomplish the tapping task of penetrating 1.2 m reinforced concrete under the premise of ensuring that the percentage of W powder is not higher than 80%. This study has a certain reference value for the selection of energy-containing materials for multifunctional warheads. For the low-velocity penetration below 400 m/s, the effect of frictional resistance of the head as well as the sidewall on the penetration depth can be ignored, but the overload curve when considering the sidewall friction is more realistic. Using a combination of experimental and theoretical methods, the influence of the projectile material on the mass erosion of high-speed kinetic energy projectiles was studied, and the Jones erosion model based on the thermal melting principle was improved. Based on the cavity expansion theory, the calculation method of the shape evolution of the bullet head was established. The comparison with the experimental results shows that the improved model is applicable to different types of soft and hard materials and can accurately calculate the mass erosion amount, erosion depth, and shape evolution of the bullet head.