University of IsfahanTaxonomy and Biosystematics3115-90011868202604016830328ENJournal Article20260318https://tbj.ui.ac.ir/article_30328_2b0dd78306594330a9a564a4e6e342b1.pdfUniversity of IsfahanTaxonomy and Biosystematics3115-9001186820260401Population-level morphological differentiation of Gudusia chapra (Hamilton, 1822) from three river systems of Bangladesh revealed by geometric morphometrics1123027510.22108/tbj.2026.146942.1321ENMojiburRahmanFBG, HSTU, Dinajpur, BangladeshAdhuryKhanomFBG, HSTU, Dinajpur-5200, BangladeshAbul HasnatSanyFaculty of Fisheries, HSTU, Dinajpur-5200, BangladeshImranParvezFBG, HSTU, Dinajpur-5200, Bangladesh0000-0001-6785-6792Journal Article20251010Previous research has demonstrated that morphological variation among riverine populations often reflects local hydrological conditions, habitat structure, and restricted connectivity among drainage systems. Understanding population-level variation is critical for accurate taxonomic resolution and effective fisheries management of widely distributed freshwater species. This study examines morphological differentiation among three riverine populations of <em>Gudusia chapra</em> from the Atrai, Padma, and Brahmaputra rivers of Bangladesh using landmark-based geometric morphometrics. Ninety specimens were analyzed using 15 homologous landmarks, with non-shape variation removed by Generalized Procrustes Analysis (GPA), followed by population-level shape divergence evaluated using Principal Component Analysis (PCA), Relative Warp Analysis (RWA), Canonical Variate Analysis (CVA), and Discriminant Function Analysis (DFA). The first two principal components explained 98.23% of the total shape variance, with PC1 (94.64%) clearly separating the Brahmaputra specimens from those of Atrai and Padma. Pairwise RWA revealed strong morphological divergence between Atrai–Brahmaputra and Brahmaputra–Padma populations, with over 95% of the variance explained by the first two components. UPGMA cluster analysis grouped individuals into three well-defined clusters corresponding to the river systems, with the Brahmaputra population forming the most cohesive cluster and Atrai showing greater within-group dispersion. CVA and DFA further supported significant morphological structuring, with the Mahalanobis and Procrustes distances between populations statistically significant (p<0.01) and an overall classification accuracy of 91.1%. These results demonstrated pronounced population-level shape divergence in <em>G. chapra</em>, likely driven by hydrological heterogeneity and localized environmental pressures. The study provides critical baseline information for stock-based management of this ecologically and commercially important species.https://tbj.ui.ac.ir/article_30275_02643cc2830c92ae90a7b63b7fea6cbd.pdfUniversity of IsfahanTaxonomy and Biosystematics3115-9001186820260401Morphological characteristics of an isolated population of the cyprinid C. saadii (Teleostei: Cyprinidae) from Kavir-e Lut basin in southeastern Iran13283018910.22108/tbj.2025.147286.1325ENAzadTeimoriDepartment of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, IranAsmaBaniasadiDepartment of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, IranMinaMotamediDepartment of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, IranMajidAskari HesniDepartment of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran0000-0001-9309-2212Journal Article20251104This study investigates the morphology of an isolated population of the cyprinid fish <em>Capoeta saadii</em> in the Nesa River within the Lut-Kavir Basin of Iran. Based on an integrated analysis of 52 specimens, the study employed meristic counts, 17 standardized morphometric characters, and seven otolith (asteriscus) morphometric characters. The studied population exhibits distinctive meristic and morphological traits, including 70–86 lateral line scales, 10–14 gill rakers, and disc- or wheel-shaped otoliths with well-developed serrated posterior margins and prominent protuberances. These features morphologically differentiate the Nesa River population from other described populations of <em>C. saadii</em> and related species such as <em>C. fusca</em>. Sexual dimorphism in meristic traits of the studied population was limited; however, it was evident in several morphometric variables and in otolith morphology, including the interorbital distance and the relative dorsal otolith length. Our findings indicate the presence of a geographically isolated population of <em>C. saadii</em> in the Lut-Kavir Basin, which is morphologically distinct and suggests potential adaptations of this riverine population to its desert environment. Robust species delimitation within the <em>C. saadii</em> complex requires confirmation from independent nuclear markers and broader comparative data (e.g., the COI gene), which should be addressed in future studies. The escalating environmental threats to the fragile freshwater ecosystems of the Kavir-e Lut Basin necessitate immediate conservation attention for this population, even as its formal taxonomic status awaits future genetic validation.https://tbj.ui.ac.ir/article_30189_8c20bc524263529a149b651840e9d8a5.pdfUniversity of IsfahanTaxonomy and Biosystematics3115-9001186820260401Taxonomy of Acantholimon species in southern Iran: A molecular phylogenetic approach29383023410.22108/tbj.2026.147757.1327ENHosseinBibakDepartment of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, IranShahrokhKazempour OsalooDepartment of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, IranMostafaAssadiBotany Research Division, Agricultural Research, Education and Extension Organization (AREEO), Research Institute of Forests and RangelandsJournal Article20251213<em>Acantholimon</em> (Plumbaginaceae) is one of the most diverse genera in Iran with 83 accepted species. Approximately 22 species are documented in the south regions of the country, 16 of which are endemic, mainly restricted to Kerman province. For this study, approximately 45 specimens were collected and analyzed to investigate taxonomic and molecular relationships. Significant taxonomic value was found in characters such as inflorescence type, flower measurements, and calyx morphology/venation. Twenty-two species (45 accessions) from four sections were analyzed using Maximum Parsimony and Bayesian methods based on nrDNA ITS and plastid rpl32-trnL <sub>(UAG)</sub> sequences. Both datasets yielded similar, highly congruent phylogenetic trees, revealing that the <em>Acantholimon</em> sections in southern Iran are not monophyletic. Notably, the <em>A. scorpius</em> population clustered with individuals from <em>A. spinicalyx</em>, despite morphological differences. This research concludes with the development of a comprehensive diagnostic key and a species distribution map for the southern Iranian taxa. These findings establish a crucial foundation for future studies on the phylogeny, classification, identification, and conservation of the genus.https://tbj.ui.ac.ir/article_30234_cb6131b4a4653cd616f9b52dbd04740d.pdfUniversity of IsfahanTaxonomy and Biosystematics3115-9001186820260401Euendemic: a proposed term for complete endemism in biogeographical classification39423027010.22108/tbj.2026.148060.1331ENFarrokhGhahremaninejadProfessor, Department of Plant Sciences, Faculty of Biological Sciences, Kharazmi University, Tehran, IranJournal Article20260105Endemism is a core concept in biogeography, yet terminology describing its different forms remains inconsistent. In particular, no formally defined term exists for taxa whose entire natural distribution is confined to a single geographical or biogeographical unit. This perspective proposes euendemic as a clear and standardized descriptor for complete endemism. The proposed term is strictly spatial and does not imply ecological specialization, evolutionary age, or conservation status. By distinguishing complete endemism from partial forms such as near or subendemism, this contribution aims to improve conceptual clarity and comparability across floristic, biogeographical and conservation studies. Examples from recent regional and global assessments illustrate that complete endemism is already widely applied as an analytical category, despite the lack of an explicit term. Formalizing this condition as euendemic provides a concise vocabulary for a commonly used but previously unnamed concept in biogeography. The proposed terminology is intended for consistent use in floristic checklists, biogeographical syntheses, and conservation assessments.https://tbj.ui.ac.ir/article_30270_2b40ed338b126865ee64e5e4a6456bef.pdf