Lateral Line Research Articles

Fish communicate with water flow to enhance a school's social network.

Schooling fish rely on a social network created through signaling between its members to interact with their environment. Previous studies have established that vision is necessary for schooling and that flow sensing by the lateral line system may aid in a school's cohesion. However, it remains unclear to what extent flow provides a channel of communication between schooling fish. Based on kinematic measurements of the speed and heading of schooling tetras (Petitella rhodostoma), we found that compromising the lateral line by chemical treatment reduced the mutual information between individuals by ∼13%. This relatively small reduction in pairwise communication propagated through schools of varying size to reduce the degree and connectivity of the social network by more than half. Treated schools additionally showed more than twice the spatial heterogeneity of fish with unaltered flow sensing. These effects were much more substantial than the changes that we measured in the nearest-neighbor distance, speed and intermittency of individual fish by compromising flow sensing. Therefore, flow serves as a valuable supplement to visual communication in a manner that is revealed through a school's network properties.

Development of the cranial lateral line system of Brook Trout, Salvelinus fontinalis (Teleostei: Salmonidae): Evolutionary and ecological implications.

The mechanosensory lateral line (LL) system of salmonid fishes has been the focus of comparative morphological studies and behavioral and physiologicalanalyses of flow sensing capabilities, but its morphology and development have not been studied in detail in any one species. Here, we describe the post-embryonic development of the cranial LL system in Brook Trout, Salvelinus fontinalis, using vital fluorescent staining (4-Di-2-ASP), scanning electron microscopy, µCT, and clearing and staining to visualize neuromasts and the process of cranial LL canal morphogenesis. We examined the relationship between the timing of LL development, the prolonged life history of salmonids, and potential ecological implications. The LL system is composed of seven canals containing canal neuromasts (CNs) and four lines of superficial neuromasts (SNs) on the skin. CNs and SNs increase in number and size during the alevin (larval) stage. CN number stabilizes as canal morphogenesis commences, but SN number increases well into the parr (juvenile) stage. CNs become larger and more elongated than SNs, but the relative area occupied by sensory hair cells decreases during ontogeny in both types of neuromasts. Neuromast-centered canal morphogenesis starts in alevins (yolk sac larvae), as they swim up into the water column from their gravel nests (~4 months post-fertilization), after which yolk sac absorption is completed and exogenous feeding begins. Canal morphogenesis proceeds asynchronously within and among canal series and is not complete until ~8 months post-fertilization (the parr stage). Three characters in the LL system and associated dermal bones were used to identify their homologs in other actinopterygians and to consider the evolution of LL canal reduction, thus demonstrating the value of salmonidsfor the study of LL evolution. The prolonged life history of Brook Trout and the onset of canal morphogenesis at swim-up are predicted to have implications for neuromast function at these critical behavioral and ecological transitions.

Schistura sonarengaensis, a new species of cave-dwelling loach (Teleostei: Nemacheilidae) from Meghalaya, northeast India.

A new species of nemacheilid loach, Schistura sonarengaensis sp. nov., is described from three cave-dwelling populations (Barak-Surma-Meghna drainage) in the South Garo Hills district of Meghalaya, India. The new species possesses prominent eyes but is easily distinguished from all the congeners of the genus Schistura from Barak-Surma-Meghna and adjacent rivers drainages of northeast Indian (except S. syngkai) in having 13-26 vertically elongated to circular mid-lateral black blotches (brownish in life) overlayered on a grayish-black mid-lateral stripe on a dull white or pale-beige (golden brown in life) body. However, it can be easily distinguished from S. syngkai in having a complete (vs. incomplete) lateral line with more 72-89 (vs. 19-42) lateral-line pored scales, greater pre-dorsal length (48.5-53.1 vs. 41.9-44.1 %SL), a wider body at dorsal-fin origin (11.3-16.7 vs. 9.4-10.3 %SL), greater dorsal (18.1-21.1 vs. 15.1-17.0 %SL) and lateral (20.9-24.1 vs. 17.4-18.9 %SL) head length, a wider head (14.5-18.5 vs. 11.6-13.3 %SL), and moderately forked (vs. emarginated) caudal fin. Further, molecular analysis confirms the distinctiveness of S. sonarengaensis sp. nov. from its congeners found in northeast India by significant divergences with uncorrected genetic distance ranging from 3.7% to 17.3% in the mitochondrial cytochrome c oxidase subunit I (COI) gene dataset. The phylogenetic position of the new species with its sister species was evaluated using maximum likelihood and Bayesian analysis. The species delimitation approaches assemble species by automatic partitioning (ASAP) and Poisson tree processes (PTP) utilized for testing species assignments consistently identified our test group as a distinct species from its sister species. Although the new species lacks typical morphological adaptations usually associated with a subterranean life, such as complete absence (or vestigial presence) of eyes and pigmentation, it exhibits a reduction of pigmentation when compared to the epigean congeners.

Effect of pH on Development of the Zebrafish Inner Ear and Lateral Line: Comparisons between High School and University Settings.

Increasing carbon dioxide levels associated with climate change will likely have a devastating effect on aquatic ecosystems. Aquatic environments sequester carbon dioxide, resulting in acidic conditions that can negatively affect fish development. Increasing climate change impacts in the coming decades will have an outsized effect on younger generations. Therefore, our research had two interconnected goals: 1) understand how aquatic acidification affects the development of zebrafish, and 2) support a high school scientist's ability to address environmental questions of increasing importance to her generation. Working with teachers and other mentors, the first author designed and conducted the research, first in her high school, then in a university research laboratory. Zebrafish embryos were reared in varying pH conditions (6.7-8.2) for up to 7 days. We assessed fish length and development of the inner ear, including the otoliths; structures that depend on calcium carbonate for proper development. Although pH did not affect fish length, fish reared in pH 7.75 had smaller anterior otoliths, showing that pH can impact zebrafish ear development. Furthermore, we demonstrate how zebrafish may be used for high school students to pursue open-ended questions using different levels of available resources.

Vein of Marshall ethanol infusion for recurrent atrial fibrillation in patients with durably isolated pulmonary veins.

Vein of Marshall (VoM) ethanol ablation has a proven benefit in patients with persistent atrial fibrillation (AF) undergoing index procedure; however, its role in repeat ablation is unknown. We sought to evaluate the benefit of empiric VoM ethanol ablation in addition to posterior wall isolation (PWI) during the repeat procedure in patients with durable pulmonary vein (PV) isolation from prior ablation. Twenty-three patients (age 67.1 + / - 7.4, 74% males) who received empiric VoM ethanol infusion in addition to PWI were matched for age, gender, ejection fraction, and left atrial size with forty-six patients receiving empiric PWI alone. All patients in the study group underwent additional ablation on mitral isthmus to complete the lateral mitral isthmus line. Additional ablation was based on program and trigger stimulation. Primary outcome was freedom from AF after a blanking period of 3months by qualification of symptoms, EKG, wearable, or implantable monitor or device. The study group had a higher average BMI (35.07 + / - 8.98 vs. 30.85 + / - 5.65, p = 0.033) and rate of persistent AF (83.0% vs. 54.3%, p = 0.029) versus the control. The 1-year AF-free survival for the study and control groups was 20 (86.96%) and 28 (60.1%) patients (p = 0.027). Cox proportional hazard regression analysis showed a significant reduction in AF recurrence in the study group (HR 0.25, 95% CI 0.073-0.843, p = 0.026). Among patients undergoing repeat catheter ablation for recurrent AF with durably isolated PVs, the addition of VoM ethanol infusion increased the likelihood of remaining free from AF at 12months.

Advances in Topical Botulinum Therapy.

A successfully developed topical botulinum toxin product would overcome the disadvantages of injectable administration commonly seen with all available botulinum products, including the potential pain, bleeding, and bruising associated with injection. Identify the disadvantages of injectable administration of botulinum products and advantages of topical administration. Identify previous attempts to develop topical products and review the only topical product candidate (ET-01, abbreviated EMX) under clinical development. A literature review regarding injectable botulinum products and topical botulinum product candidates and an analysis of data regarding EMX development were performed. Multiple disadvantages of injectable administration and advantages of topical administration of botulinum toxin were identified. If available, topical botulinum products are expected to expand the clinical use of botulinum toxin. Several previous attempts to develop topical products were identified. EMX has been studied for lateral canthal line treatment in multiple controlled phase 2 clinical trials including over 700 subjects. EMX has demonstrated statistically significant positive results. The development of a topical botulinum toxin is appealing because it overcomes multiple disadvantages observed with injectable administration and would likely result in increased clinical use of botulinum toxin. The development of EMX shows promise and merits further study.

Education of lateral lines of the Radziwill family in the 18th century. A marker of social status or a chance for advancement?

Education of lateral lines of the Radziwill family in the 18th century. A marker of social status or a chance for advancement?

Assessment of some egg quality parameters and chorion ultrastructure characterization in Atlantic salmon (Salmo salar)

Farmed salmonid production requires oocytes and embryos of high quality to supply the increasing market demand; achieving this depends primarily on the management of females and gametes. The chorion of the fertilized egg is a crucial structure for embryo protection; however, it is still poorly studied in some fish species. The object of the present study was to evaluate some parameters of oocyte quality and embryonic development in S. salar, and to characterize the chorion at the ultrastructural level in oocytes and embryos at different stages up to hatching by scanning electron microscopy (SEM). The samples (oocytes and embryos) were obtained from five mature females (4 years old, 9.75 ± 0.86 kg) of S. salar. The results show 32% (20%; 64%) of oocytes with yolk clots, a hydration percentage of 17% (11.1%; 23.3%) and a significant increase in embryo hardness at 12 accumulated thermal units (ATU). A mean fertility rate of 77% (60%; 93%) was recorded. The survival rates were 72% (20%; 100%) and 73% (32%; 92%) for 130 and 318 ATU, respectively. The values of symmetrical blastomeres were high, 65% (45%; 80%); however, the rate of spine deformities was also high at 42.4% (22%; 71%). Several significant correlations were observed between the parameters assessed: there were high-positive correlations between the hydration percentage and blastomere symmetry (r = 0.89), between oocyte hardness and spine deformities (r = 0.88), and between embryo hardness at 130 and 318 ATU (r = 0.97); there were also strong correlations between symmetry and survival rate at 130 ATU (r = 0.95) and between symmetry and survival rate at 318 ATU (r = 0.96). In the ultrastructural analysis, the SEM images revealed that the outer layer of the chorion of both oocytes and fertilized eggs, through development to hatching, exhibits a granular pattern. In contrast, the inner layer is composed of numerous interconnected fibres that form a complex network, absent in the hatching area. Both outer and inner layers show numerous pore canals. The pores in the outer layer are covered by plugs, and are larger than those in the inner layer. The information generated in this study is useful to complement understanding of the biology of S. salar eggs; however, given the ultrastructural variability of the chorion, further studies are needed to expand on these findings.

Label-free multiphoton imaging reveals volumetric shifts across development in sensory-related brain regions of a miniature transparent vertebrate.

Animals integrate information from different sensory modalities as they mature and perform increasingly complex behaviors. This may parallel differential investment in specific brain regions depending on the demands of changing sensory inputs. To investigate developmental changes in the volume of canonical sensory integration brain regions, we used third harmonic generation imaging for morphometric analysis of forebrain and midbrain regions from 5 to 90 days post fertilization (dpf) in Danionella dracula , a transparent, miniature teleost fish whose brain is optically accessible throughout its lifespan. Relative to whole brain volume, increased volume or investment in telencephalon, a higher order sensory integration center, and torus longitudinalis (TL), a midbrain visuomotor integration center, is relatively consistent from 5 to 30 dpf, until it increases at 60 dpf, followed by another increase at 90 dpf, as animals reach adulthood. In contrast, investment in midbrain optic tectum (TeO), a retinal-recipient target, progressively decreases from 30-90 dpf, whereas investment is relatively consistent across all stages for the midbrain torus semicircularis (TS), a secondary auditory and mechanosensory lateral line center, and the olfactory bulb (OB), a direct target of the olfactory epithelium. In sum, increased investment in higher order integration centers (telencephalon, TL) occurs as juveniles reach adulthood and exhibit more complex cognitive tasks, whereas investment in modality-dominant regions occurs in earlier stages (TeO) or is relatively consistent across development (TS, OB). Complete optical access throughout Danionella 's lifespan provides a unique opportunity to investigate how changing brain structure over development correlates with changes in connectivity, microcircuitry, or behavior.

Fracture Lines and Patterns in Intra-articular Distal Femur Fractures.

Distal femur fractures are complex injuries that often present with multiple fragments, posing notable challenges to fixation. This study aimed to (1) use preoperative CT scans to graphically display fracture lines in intra-articular distal femur fractures and (2) identify common fracture patterns in these injuries. All skeletally mature patients that underwent surgical fixation of Orthopaedic Trauma Association type 33C distal femur fractures between 2012 and 2022 were identified across two level 1 trauma centers (n = 63). Preoperative axial, sagittal, and coronal computed tomography scans were obtained. Fracture lines in each plane were traced out and superimposed on standardized distal femur cross-sections, generating a fracture map for each plane. Injury and fracture characteristics were summarized and compared between fracture patterns. On axial scans, 59 of 63 fractures contained a central intercondylar split from the intercondylar notch to the trochlea. On coronal scans, fracture lines originated at the notch and exited laterally and medially in the supracondylar region, creating a Y-shape. One-third of all fractures contained coronal fracture lines, with most involving the lateral condyle. Based on fracture line orientation and location, fractures were divided into four main fracture pattern types. Type 4 fractures (central split and medial coronal fracture line) were associated with lower average medial fracture height and a lower rate of medial metaphyseal comminution. We found that C-type distal femur fractures can present with four main fracture patterns. Most fractures contain a central sagittal intercondylar split, and a high proportion of fractures contain either medial or lateral coronal fracture lines. Fracture pattern was associated with mechanism of injury, presence of medial comminution, and medial fracture line height. Future studies should focus on clinical outcomes and surgical management of these distinct fracture patterns. IV.

Scale Characteristics of Six Fish Species of the Genus Cyprinion (Teleostei: Cypriniformes): A Microscopic Analysis.

This study investigated the morphological characteristics of scales in six Cyprinion species, using light and scanning electron microscopy focusing on key features such as scale type, key scales, lateral line scales, radius/radii, rostral margin, focus, circuli, lepidonts, tubercles, and scale indices. The research analyzed the scales using ultramicroscopy and light microscopy imaging, categorizing them based on size classes and body regions. The morphological variations in scale characteristics were examined across different species, regions, and size classes. Notable findings included the tetra-sectioned form of scales, representing a unique characteristic of the Cyprinion genus. Morphological changes in scale features were observed with fish growth, particularly in the overall shape, focus shape, and size. Quantitative analysis revealed variations in average relative scale length and width among different species, regions, and size classes. The study utilized canonical discriminant analysis for multivariate assessment, classifying the species into distinct groups based on morphometric indices. The findings contribute to the understanding of scale morphology in Cyprinion species and exploring morphological variation between the examined species.

Comparison of the use of biocompatible materials and titanium in the treatment of midshaft clavicle fractures with a patient-specific plate: a finite element analysis study.

Clavicular midshaft fractures treated with titanium plates may encounter complications like implant failure. We assess if alternative biocompatible materials suchs as PLA, PLA/HA, PEEK offer comparable stability. Our study evaluates the biomechanical performance of these materials in surgical management of midshaft clavicle fractures. We simulated a personalized fixation implant with four different materials and conducted finite element analysis in ANSYS to assess maximum von Mises stress (MvMs). The MvMs occurring on the plates, screws, clavicle, and fracture site were recorded. MvMs on titanium material at the 6th hole level (764.79MPa) and the 6th screw level (503.38MPa), with the highest stresses observed at 48.52MPa on the lateral clavicle at the 1st hole level and 182.27MPa on the medial clavicle at the 6th hole level. In PLA material analyses, the highest MvMs were observed at the 3rd hole level (340.6MPa) and the 3rd screw level (157.83MPa), with peak stresses at 379.63MPa on the lateral clavicle fracture line and 505.44MPa on the medial clavicle fracture line. In PLA/HA material analyses, the highest MvMs were at the 3rd hole (295.99MPa) and 3rd screw (128.27MPa), with peak stresses at 220.33MPa on the lateral clavicle and 229.63MPa on the medial clavicle fracture line. In PEEK material analyses, the highest MvMs were at the 3rd hole (234.74MPa) and 6th screw (114.48MPa), with peak stresses at 184.36MPa on the lateral clavicle and 180.1MPa on the medial clavicle. Our findings indicate that titanium material shows significantly higher stresses on plates and screws compared to those on the clavicle, suggesting a risk of implant failure. PLA and PLA/HA were inadequate for fixation. Although stress on the plate with PEEK material is higher than on the clavicle, it remains lower than titanium, indicating potential stability at fracture site. Further research is needed to confirm these findings.

Multiple mechanisms of aminoglycoside ototoxicity are distinguished by subcellular localization of action.

Mechanosensory hair cells of the inner ears and lateral line of vertebrates display heightened vulnerability to environmental insult, with damage resulting in hearing and balance disorders. An important example is hair cell loss due to exposure to toxic agents including therapeutic drugs such as the aminoglycoside antibiotics such as neomycin and gentamicin and antineoplastic agents. We describe two distinct cellular pathways for aminoglycoside-induced hair cell death in zebrafish lateral line hair cells. Neomycin exposure results in death from acute exposure with most cells dying within 1 hour of exposure. By contrast, exposure to gentamicin results primarily in delayed hair cell death, taking up to 24 hours for maximal effect. Washout experiments demonstrate that delayed death does not require continuous exposure, demonstrating two mechanisms where downstream responses differ in their timing. Acute damage is associated with mitochondrial calcium fluxes and can be alleviated by the mitochondrially-targeted antioxidant mitoTEMPO, while delayed death is independent of these factors. Conversely delayed death is associated with lysosomal accumulation and is reduced by altering endolysosomal function, while acute death is not sensitive to lysosomal manipulations. These experiments reveal the complexity of responses of hair cells to closely related compounds, suggesting that intervention focusing on early events rather than specific death pathways may be a successful therapeutic strategy.

The Silverjaw Minnow, Ericymba buccata: An Extraordinary Lateral Line System and its Contribution to Prey Detection.

Fishes use their mechanosensory lateral line (LL) system to detect local water flows in different behavioral contexts, including the detection of prey. The LL system is comprised of neuromast receptor organs on the skin (superficial neuromasts) and within bony canals (canal neuromasts). Most fishes have one cranial LL canal phenotype, but the silverjaw minnow (Ericymba buccata) has two: narrow canals dorsal and caudal to the eye and widened canals ventral to the eye and along the mandible. The ventrally directed widened LL canals have been hypothesized to be an adaptation for detection of their benthic prey. Multiple morphological methods were used to describe the narrow and widened canals and canal neuromasts in detail. The primary distribution of hundreds of superficial neuromasts and taste buds ventral to the eye and on the mandible (described here for the first time) suggests additional sensory investment for detecting flow and chemical stimuli emanating from benthic prey. The hypothesis that the LL system mediates prey localization was tested by measuring five parameters in behavioral trials in which the combination of sensory modalities available to fish was manipulated (four experimental treatments). Fish detected and localized prey regardless of available sensory modalities and they were able to detect prey in the dark in the absence of LL input (LL ablation with neomycin sulfate) revealing that chemoreception was sufficient to mediate benthic prey detection, localization, and consumption. However, elimination of LL input resulted in a change in the angle of approach to live (mobile) prey even when visual input was available, suggesting that mechanosensory input contributes to the successful detection and localization of prey. The results of this study demonstrate that the extraordinary LL canal system of the silverjaw minnow, in addition to the large number of superficial neuromasts, and the presence of numerous extraoral taste buds, likely represent adaptations for multimodal integration of sensory inputs contributing to foraging behavior in this species. The morphological and behavioral results of this study both suggest that this species would be an excellent model for future comparative structural and functional studies of sensory systems in fishes.

Fractal morphology of mechanosensory lateral-line canals in Stichaeidae

Fractal morphology of mechanosensory lateral-line canals in Stichaeidae

Parallel phenotypic evolution of two independent cavefish lineages of Astyanax mexicanus (De Filippi, 1854) (Characiformes: Characidae)

Abstract Astyanax mexicanus offers a unique model for studying parallel evolution, with cave-dwelling forms arising from at least two distinct surface lineages. Here, we examined repeated evolution in the two cave-adapted lineages across four phenotypic datasets: (i) meristic data; (ii) ecomorphological data; and geometric morphometric data for (iii) head and (iv) premaxillary bone shape. Additionally, we assessed the association of these phenotypes with their phylogenetic history. Certain traits exhibited evidence of parallel evolution for the cave ecotype across lineages, such as increased maxillary tooth count, reduced lateral line scale count, and shorter ascending process of the premaxillary bone. Geometric morphometric data showed a phenotypic divergence gradient in head shape between cave and surface populations, with the strongest divergence between Sierra de El Abra and surface populations and with less differentiation between surface populations and caves from Sierra de Guatemala and Micos. Cave populations that hybridize with surface populations (e.g. Micos) displayed the greatest overlap with the surface ecotype. There was a similar divergence gradient for premaxillary bone shape, but with weaker differentiation between cave and surface ecotypes. This evidence of repeated evolution in several cave traits emphasizes the significance of selective pressures exerted by the environment on the evolution of cave ecotypes.

Hybrid nanoflower-based electrochemical lateral flow immunoassay for Escherichia coli O157 detection.

An electrochemical biosensor has been developedfor detection of Escherichia coli O157 by integrating lateral flow with screen-printed electrodes. The screen-printed electrodes were attached under the lateral flow detection line, and organic-inorganic nanoflowers prepared from E. coli O157-specific antibodies as an organic component were attached to the lateral flow detection line. In the presence of E. coli O157, an organic-inorganic nanoflower-E. coli O157-antimicrobial peptide-labelled ferrocene sandwich structure is formed on the lateral flow detection line. Differential pulse voltammetry is applied using a smartphone-based device to monitor ferrocene on the detection line. The resulting electrochemical biosensor could specifically detect E. coli O157 with a limit of detection of 25 colony-forming units mL-1. Through substitution of antibodies of organic components in organic-inorganic nanoflowers, biosensors have great potential for the detection of other pathogens in biomedical research and clinical diagnosis.

Schooling Fish from a New, Multimodal Sensory Perspective.

The acoustic hypothesis suggests that schooling can result in several benefits. (1) The acoustic pattern (AP) (pressure waves and other water movements) produced by swimming are likely to serve as signals within fish shoals, communicating useful spatial and temporal information between school members, enabling synchronized locomotion and influencing join, stay or leave decisions and shoal assortment. (2) Schooling is likely to reduce the masking of environmental signals, e.g., by auditory grouping, and fish may achieve windows of silence by simultaneously stopping their movements. (3) A solitary swimming fish produces an uncomplicated AP that will give a nearby predator's lateral line organ (LLO) excellent information, but, if extra fish join, they will produce increasingly complex and indecipherable APs. (4) Fishes swimming close to one another will also blur the electrosensory system (ESS) of predators. Since predators use multimodal information, and since information from the LLO and the ESS is more important than vision in many situations, schooling fish may acquire increased survival by confusing these sensory systems. The combined effects of such predator confusion and other acoustical benefits may contribute to why schooling became an adaptive success. A model encompassing the complex effects of synchronized group locomotion on LLO and ESS perception might increase the understanding of schooling behavior.

Complexes of vertebrate TMC1/2 and CIB2/3 proteins form hair-cell mechanotransduction cation channels.

Calcium and integrin-binding protein 2 (CIB2) and CIB3 bind to transmembrane channel-like 1 (TMC1) and TMC2, the pore-forming subunits of the inner-ear mechano-electrical transduction (MET) apparatus. These interactions have been proposed to be functionally relevant across mechanosensory organs and vertebrate species. Here we show that both CIB2 and CIB3 can form heteromeric complexes with TMC1 and TMC2 and are integral for MET function in mouse cochlea and vestibular end organs as well as in zebrafish inner ear and lateral line. Our AlphaFold 2 models suggest that vertebrate CIB proteins can simultaneously interact with at least two cytoplasmic domains of TMC1 and TMC2 as validated using nuclear magnetic resonance spectroscopy of TMC1 fragments interacting with CIB2 and CIB3. Molecular dynamics simulations of TMC1/2 complexes with CIB2/3 predict that TMCs are structurally stabilized by CIB proteins to form cation channels. Overall, our work demonstrates that intact CIB2/3 and TMC1/2 complexes are integral to hair-cell MET function in vertebrate mechanosensory epithelia.

Description of Aphelenchoides yixingensis n. sp. (Tylenchina: Aphelenchoididae) found in Pinus massoniana from China, and proposal for genus Ptychaphelenchus as a synonym of Aphelenchoides

Summary Aphelenchoides yixingensis n. sp. found in Chinese red pine (Pinus massoniana) in Yixing city, Jiangsu Province, P.R. China, is described. It is characterised by a very slim body (a = 50.8 (41.3-63.8) and 49.3 (42.3-55.1) for males and females, respectively), three (occasionally five) lateral lines in the lateral field, a short stylet (9-12 μm), the excretory pore located at the level of nerve ring, the vagina is not sclerotised and the vulva has slightly protruding lips and lacks a flap, the post-uterine sac is well developed and forms ca 29.0% (24.1-34.1%) of the vulva to anus distance. The spicules are smoothly arcuate, the apex and rostrum rounded and short, and the dorsal limb is 20.5 (16.9-22.2) μm long, the distal end bluntly rounded. Spicule sheath-like structure is present, triangular and outstretched when heat-killed in some individuals. The male tail bears three pairs (2 + 2 + 2) of caudal papillae. The tail of both sexes is sub-cylindrical, the terminus bearing a bluntly pointed mucron with tiny nodular protuberances, mainly at the distal part. The new species belongs to the Group 2 category of Aphelenchoides species sensu Shahina and is defined as A2-B1-C1-D1-E2-F2 according to the categorisation codes of OEPP/EPPO. Phylogenetic analysis based on 18S and 28S D2-D3 of rDNA, along with ITS and mtCOI, confirmed its status as a new species. A proposal for genus Ptychaphelenchus as a synonym of Aphelenchoides is also discussed.