First Record of African Angel Shark, Squatina africana (Chondricthyes: Squatinidae) in Indian Waters, Confirmed by DNA Barcoding

Ambily, M. N.; Zacharia, P U; Najmudeen, T M; Ambily, L.; Sunil, K. T. S.; Radhakrishnan, M.; Kishor, T. G.

doi:10.1134/s0032945218030013

Cited by 5 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All species delimitations split S. africana into four MOTUs. A recent study which included sequences from South Africa and Indian Ocean specimens, found a high number of haplotypes within S. africana [73] using DNA fragments of COI gene, and with a high K2-P genetic distances (up to 2.5%), when compared with values reported in this study between other pairs of nominal Squatina species (e.g., 0.99% between specimens of S. albipunctata and S. pseudocellata). Similar to S. californica, the split of S. africana into 4 MOTUs may be explained due to the life-traits of angel sharks and the geographical barriers.…”

Section: Discussioncontrasting

confidence: 44%

Species Delimitation of Southeast Pacific Angel Sharks (Squatina spp.) Reveals Hidden Diversity through DNA Barcoding

Cañedo-Apolaya

Ortiz‐Alvarez²,

Alfaro-Córdova³

et al. 2021

Diversity

View full text Add to dashboard Cite

Angel sharks are distributed worldwide in tropical to subtropical waters. Across the Eastern Pacific Ocean (EPO), two valid species are reported: The Pacific angelshark Squatina californica and the Chilean angelshark Squatina armata; however, there is still uncertainty about their geographic distribution, mainly along the northern Peru coast where the species have been reported to be sympatric. The aim of this study is to describe the genetic differences between the genus Squatina from the EPO, including samples from northern Peru, and using DNA barcoding and three species delimitation models: Poisson tree processes (PTP) model, Bayesian implementation of the PTP (bPTP) model and the general mixed Yule coalescent (GMYC) model. The three approaches summarized 19 nominal Squatina species in 23 consensus Molecular Taxonomic Units (MOTU). Only 16 of them were in accordance with taxonomic identifications. From the EPO, four Squatina MOTUs were identified, one from North America (S. californica USA/Mexico) and three sampled in northern Peru, S. californica Peru, S. armata and Squatina sp. (a potential new species). This study contributes to the management and conservation policies of angel sharks in Peru, suggesting the presence of an undescribed species inhabiting the northern Peruvian coast. The use of molecular approaches, such as DNA barcoding, has the potential to quickly flag undescribed species in poorly studied regions, including the Southeast Pacific, within groups of ecologically and economically important groups like angel sharks.

show abstract

Section: Discussioncontrasting

confidence: 44%

Species Delimitation of Southeast Pacific Angel Sharks (Squatina spp.) Reveals Hidden Diversity through DNA Barcoding

Cañedo-Apolaya

Ortiz‐Alvarez²,

Alfaro-Córdova³

et al. 2021

Diversity

View full text Add to dashboard Cite

show abstract

“…However, despite the interdependence of both disciplines, their synergic and harmonic application has not been as frequent as needed. Recent taxonomic studies on angel sharks (Vaz & de Carvalho 2013 and other successful examples of combining taxonomy and genetics (Ambily et al 2018), with this updated morphological characterization of the Chilean angel shark, questions on geographic range, estimations of abundance, and real incidence in landings can be clarified to ultimately inform better conservation practices of this critically endangered species (Dulvy et al 2020) and other angel sharks on the Pacific coast of America.…”

Section: Conservationmentioning

confidence: 99%

“…Recent efforts in identifying and describing angel sharks have adopted a more integrative approach by combining morphology with other disciplines, such as genetics (Padial et al 2010;Long et al 2021). For example, the identification of the African angel shark Squatina africana Regan, 1908 was improved by combining morphology and DNA-barcoding, enabling a better delimitation of its distribution range which was expanded into the southwestern Indian Ocean (Ambily et al 2018). In addition, genetic data have been successfully used in identifying angel sharks and in constructing phylogenies (e.g., Stelbrink et al 2010;Vélez-Zuazo & Agnarsson 2011;Naylor et al 2012;López-Romero et al 2020), which has been particularly useful when studying co-occurring species.…”

Section: Introductionmentioning

confidence: 99%

Redescription of the Chilean angel shark Squatina armata (Philippi, 1887) (Squatiniformes, Squatinidae)

Kraft,

Fernández-Cisternas,

Araya

et al. 2024

EJT

View full text Add to dashboard Cite

Angel sharks (Squatina spp. Duméril, 1805) are a group of coastal benthic sharks distributed worldwide, currently including threatened and understudied species. Two species are formally described along the East Pacific coast, the California angel shark S. californica Ayres, 1859 and the Chilean angel shark S. armata (Philippi, 1887). The latter species occurs in the southeastern Pacific and has historically been understudied. Additionally, the original description of S. armata lacks sufficient data to confidently identify individuals of this species compared to modern descriptions, and no type specimen is currently available to ensure specimen identification. Detailed morphological descriptions for identifying species are an essential resource for solving taxonomic issues in groups of morphologically similar species and to promote the conservation of critically endangered species. Therefore, a neotype from the type locality is here designated for S. armata, and a detailed and standardized morphological characterization based on modern taxonomic works is provided. This work contributes in improving the knowledge on the Chilean angel shark taxonomy and provides an improved frame of reference for identifying angel sharks in the East Pacific, especially in areas where species may occur in sympatry.

show abstract

“…Figure 1 illustrates the numerical model and mesh configurations utilized in the analysis. While the cylindrical unit cell model can be conceptualized as a 3D model with the vertical axis passing through the column center, geometric constraints in PLAXIS necessitated the adoption of a square unit cell equivalent, as utilized in earlier studies (Ambily;Gandhi, 2007;Samadhiya, 2016a). Consequently, a square unit cell model was employed in this study.…”

Section: Numerical Modelingmentioning

confidence: 99%

“…Several researchers have investigated the behavior of Sand-Fiber Mix (SFM) or geogrids using both numerical and experimental methods. For instance, comprehensive parametric studies involving random fibers have been conducted to analyze the behavior of SFM and assess the impact of factors such as fiber length, depth, and quantity on the bearing capacity of sand piles (Ambily;Gandhi, 2007;Shooshpasha, 2017;Malarvizhi;Ilamparuthi, 2008;Murugesan;Rajagopal, 2010).…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of the effectiveness of recycled aggregates in reinforcing soft soil with granular columns

Yousfi,

Guettala,

Farik

et al. 2024

SEES

View full text Add to dashboard Cite

In recent years, the civil engineering field has increasingly focused on recycled aggregates due to the dwindling availability of natural aggregates and the high carbon footprint associated with their extraction and use. The use of recycled aggregates aims to decrease energy consumption and lessen the environmental impact caused by construction waste. This study illustrates the value of utilizing recycled aggregate materials for soil reinforcement and demonstrates their efficiency compared to natural aggregates. The research employs several numerical simulations carried out using PLAXIS 3D, a finite element software renowned for its advanced modeling capabilities. These simulations leverage the Mohr-Coulomb failure criteria alongside an elastic-perfectly plastic behavior model to assess the performance of various materials under different conditions. Specifically, the study investigates three types of granular columns—Ordinary Stone Columns (OSC), Sand-Fiber Mix (SFM), and Recycled Aggregate Porous Concrete Piles (RAPP)—to reinforce a unit cell model of soft soil under failure loading scenarios. Detailed analysis reveals that recycled aggregate columns exhibit a significantly higher bearing capacity, showing an improvement of up to three times that of columns made with natural aggregates. This superior performance is attributed to the enhanced mechanical properties and better load distribution capabilities of the recycled aggregates. The results are presented through load-settlement curves, which provide a clear visualization of the effectiveness of each type of granular column. Furthermore, the study highlights the practical implications of using recycled aggregates in soil reinforcement projects. The substantial improvements in bearing capacity demonstrated by the recycled aggregate columns underscore their potential as a viable and sustainable alternative to natural aggregates in various geotechnical applications.

show abstract

First Record of African Angel Shark, Squatina africana (Chondricthyes: Squatinidae) in Indian Waters, Confirmed by DNA Barcoding

Cited by 5 publications

References 12 publications

Species Delimitation of Southeast Pacific Angel Sharks (Squatina spp.) Reveals Hidden Diversity through DNA Barcoding

Species Delimitation of Southeast Pacific Angel Sharks (Squatina spp.) Reveals Hidden Diversity through DNA Barcoding

Redescription of the Chilean angel shark Squatina armata (Philippi, 1887) (Squatiniformes, Squatinidae)

Numerical modeling of the effectiveness of recycled aggregates in reinforcing soft soil with granular columns

Contact Info

Product

Resources

About