http://repository.sungshin.ac.kr/handle/2025.oak/171 Mon, 23 Mar 2026 21:34:25 GMT 2026-03-23T21:34:25Z http://repository.sungshin.ac.kr/handle/2025.oak/8871 Title: There and back again: historical biogeography of neotropical magnolias based on high-throughput sequencing Author(s): 김상태; Salvador Guzman‑Diaz; Fabián Augusto Aldaba Núñez; Emily Veltjen; Pieter Asselman; José Esteban Jiménez; Jorge Valdés Sánchez; Guillermo Pino Infante; Ricardo Callejas Posada; José Antonio Vázquez García; Isabel Larridon; Suhyeon Park; Esteban Manuel Martínez Salas; Marie‑Stéphanie Samain Abstract: Background The Neotropics are considered one of the most biodiverse areas in the world, housing at least one third of all vascular plant species. One of the genera that has diversified in the Neotropics is Magnolia, with about 174 species of three sections (Macrophylla, Magnolia and Talauma) endemic to the Americas. In this work, we study the biogeographic history of the Neotropical Magnolia species using high-throughput sequencing data. Sequences from 39 species (38 from Magnolia and one from the sister genus Liriodendron) were assembled. The dataset contained sequences from 239 nuclear targets and complete chloroplast genomes. Phylogenomic hypotheses and the ancestral distribution range of Magnolia were reconstructed. Results The results of the calibrated phylogenetic hypotheses and ancestral range construction suggest that the earliest arrival in the Neotropics were the ancestors of section Talauma (38 million years ago), which colonized the Pacific region. This early presence in South America suggests long-distance, overwater dispersal from North America, the presumed origin of the genus Magnolia. The analysis and the extant Talauma distribution indicate a south to north recolonization. The ancestors of the other two Neotropical sections, Magnolia and Macrophylla, migrated around 19 mya from Asia to North Am Tue, 29 Apr 2025 15:00:00 GMT http://repository.sungshin.ac.kr/handle/2025.oak/8871 2025-04-29T15:00:00Z http://repository.sungshin.ac.kr/handle/2025.oak/8870 Title: East Asia-eastern North America disjunction revisited: Possible westward colonization route via the Western Palearctic in Carex sect. Paniceae (Cyperaceae) Author(s): 김상태; Yi-Fei Lu; Carmen Benítez‐Benítez; Okihito Yano; Hiroshi Ikeda; Sae‐Eun Jung; PedroJiménez‐Mejías; Xiao‐Feng Jin Abstract: Carex sect. Paniceae sensu lato (s.l.) exhibits two major disjunct centers of diversity: eastern North America and East Asia. This pattern, commonly observed in other plant groups, has been associated with trans-Pacific dispersal from Asia to America and subsequent local extinctions in western North America. This study reconstructed a phylogenetic tree using two nuclear (external transcribed spacer and internal transcribed spacer) and three plastid (matK, trnL-F, and rpl32-trnLUAG) regions, along with 474 nuclear loci from high-throughput sequencing (Hyb-Seq). Dating analysis and ancestral area reconstruction were used to investigate the evolutionary and biogeographic history of sect. Paniceae s.l. A broader circumscription of sect. Paniceae s.l., incorporating sects. Bicolores and Laxiflorae, is established. Two primary clades were identified: one clade predominantly diversified in North America and the other in East Asia. Biogeographic analyses suggested a likely origin of sect. Paniceae s.l. in the Palearctic during the Late Miocene. The most probable scenario involved dispersal to eastern North America via the Western Palearctic, followed by subsequent dispersal into western North America, other parts of the continent, and back to the Old World. Within East Asia, the group was inferred to have diversified du Thu, 17 Jul 2025 15:00:00 GMT http://repository.sungshin.ac.kr/handle/2025.oak/8870 2025-07-17T15:00:00Z http://repository.sungshin.ac.kr/handle/2025.oak/8869 Title: Unravelling the Mexican Magnolia dealbata (Magnoliaceae) species complex Author(s): 김상태; FABIÁN AUGUSTO ALDABA NÚÑEZ; SALVADOR GUZMÁN-DÍAZ; SUHYEON PARK; ESTEBAN MANUEL MARTÍNEZ SALAS; MARIE-STÉPHANIE SAMAIN Abstract: In the last two decades, approximately 80 new Magnolia species have been described from the Neotropics; thus this region now hosts almost half of the world’s known Magnolia diversity. Many of these likely are not segregate taxa but rather separate populations or groups of populations of the previously broadly circumscribed, widespread species. Such is possibly the case of the Magnolia dealbata species complex (belonging to Magnolia sect. Macrophylla), distributed throughout the Sierra Madre Oriental mountain range in Eastern Mexico. This species complex has been divided into six morphospecies based on morphological criteria only. However, recent microsatellite markers have suggested that these may be a single entity. Considering geographical data and the isolation of populations, we hypothesised that the different morphospecies could form two entities, corresponding to the north and centre of the Sierra Madre Oriental. This hypothesis was tested by morphological observations, chloroplast comparisons and phylogenetic analyses of plastomes, angiosperm DNA plastid barcodes and Magnolia-specific plastid DNA barcodes from hypervariable regions. Phylogenetic results from plastomes and angiosperm DNA plastid barcodes refute the multispecies hypothesis and show that the six morphospecies of this complex inhabiting the S Tue, 04 Feb 2025 15:00:00 GMT http://repository.sungshin.ac.kr/handle/2025.oak/8869 2025-02-04T15:00:00Z http://repository.sungshin.ac.kr/handle/2025.oak/8868 Title: A survey of neural network segmentation and validation on plant specimen images of Korean Violaceae Author(s): 김상태; Sujeong Han; Hyeonji Moon; Sanghyuck Lee; A-Seong Moon; Min-Kyung Sung; Jeongwon Lee; Jaesung Lee Abstract: Accurate plant identification is crucial for biodiversity research, yet manual classification remains timeconsuming and requires specialized expertise. To overcome these challenges automated identification technologies are increasingly being developed. A key step in this process is the precise segmentation of plant materials from plant specimen images; however, existing approaches often struggle to separate plant material from nonplant components such as labels, barcodes, stamps, and rulers. To address this problem, we propose integrating Multi Receptive Field (MRF) blocks into a U-Net framework, enabling robust multi-scale feature extraction from plant bodies of varying sizes in digitized specimens. We conduct extensive experiments on a dataset of 14,939 plant specimen images from 36 species of Viola (Violaceae), comparing the performance of eleven segmentation models, including ten state-of-the-art methods and our approach. The proposed model achieved superior performance with a mean Intersection over Union of 0.8531, Dice coefficient of 0.9123, and pixel accuracy of 0.9920. Through ablation studies, we established that incorporating six different kernel sizes in the MRF block yields optimal segmentation results. By effectively addressing the complexities inherent in herbarium images such as varying plant scal Tue, 22 Jul 2025 15:00:00 GMT http://repository.sungshin.ac.kr/handle/2025.oak/8868 2025-07-22T15:00:00Z