https://repository.kopri.re.kr/handle/201206/15845 2026-03-18T15:16:23Z 2026-03-18T15:16:23Z Vinther, Jakob Parry, Luke A Lee, Mirinae Nielsen, Morten Lunde Oh, Yeongju Park, Changkun Kim, Ji-Hoon DeVivo Giacinto Harper David A. T. Nielsen Arne T. Park, Tae-Yoon S. https://repository.kopri.re.kr/handle/201206/16008 2025-08-21T05:53:46Z 2025-07-01T00:00:00Z

Title: A fossilized ventral ganglion reveals a chaetognath affinity for Cambrian nectocaridids Authors: Vinther, Jakob; Parry, Luke A; Lee, Mirinae; Nielsen, Morten Lunde; Oh, Yeongju; Park, Changkun; Kim, Ji-Hoon; DeVivo Giacinto; Harper David A. T.; Nielsen Arne T.; Park, Tae-Yoon S. Abstract: Nectocaridids are enigmatic Palaeozoic animals with a controversial phylogenetic position. Previous hypotheses have placed them in their own phylum, chordates, molluscs (specifically cephalopods), or radiodont panarthropods. We describe here a nectocaridid, Nektognathus evasmithae gen. et sp. nov. from the early Cambrian (similar to 519 million years) Sirius Passet Lagerstatte of North Greenland. Key specimens preserve paired, phosphatized arcuate structures consistent with preservation of a ventral ganglion, a feature characteristic of extant and fossil chaetognaths, including the amiskwiid Timorebestia koprii also from Sirius Passet. Nektognathus shares a gnathostomulid-like jaw apparatus, lateral fins, subterminal anus, and large antennae with Timorebestia and Amiskwia, placing nectocaridids in the chaetognath stem lineage. The complex sensory anatomy of nectocaridids, which is partially shared with other extinct amiskwiids, highlights a more dynamic predatory lifestyle much higher in the trophic food chain during early chaetognath evolution.

2025-07-01T00:00:00Z Nielsen, Morten Lunde Lee, Mirinae Wilby, Philip R. Park, Tae-Yoon S. Nielsen, Arne T. Vinther, Jakob https://repository.kopri.re.kr/handle/201206/16010 2025-11-05T04:53:12Z 2025-07-01T00:00:00Z

Title: Negative ontogenetic allometry of cardinal spines in the early Cambrian arthropod Isoxys volucris indicates their defensive function Authors: Nielsen, Morten Lunde; Lee, Mirinae; Wilby, Philip R.; Park, Tae-Yoon S.; Nielsen, Arne T.; Vinther, Jakob Abstract: The characteristic cardinal spines of Isoxys, a cosmopolitan bivalved arthropod, have been focal to understanding its role in Cambrian ecosystems. It has been proposed that the spines had either a hydrodynamic function, to aid buoyancy, or a defensive function, to protect against predators. Here, we demonstrate that the unusually elongated cardinal spines in Isoxys volucris (by far the most abundant taxon in the lower Cambrian Sirius Passet Lagerstatte, North Greenland) had a primary defensive function. Spine measurements of 85 specimens show a negative allometry during ontogeny, with the ratio of cardinal spine length to carapace length decreasing from >3.2 to 0.9. Negative allometric growth is inconsistent with a hydrodynamic function since larger carapaces would require spines which are proportionally at least as long (isometry or positive allometry). Instead, the negative allometry provides evidence for a defensive adaptation comparable to that seen in modern lower-trophic organisms, in which elongated spines increase the overall size of juveniles to deter predators. Isoxys volucris was the dominant food source for higher-trophic benthic and pelagic predators in the Sirius Passet biota, as revealed by the gut contents of arthropods, lobopods, palaeoscolecids and stem-chaetognaths. Its long spines therefore indicate similar adaptive responses to extremely high predation pressures in both modern and early Cambrian ecosystems.

2025-07-01T00:00:00Z Park, Tae-Yoon S. Oh, Yeongju Lee, Mirinae Kim Taehwan https://repository.kopri.re.kr/handle/201206/16243 2025-10-28T09:06:09Z 2024-12-01T00:00:00Z

Title: Tectonic evolution of the Korean Peninsula: A new paradigm for critical building blocks of East Asia Authors: Park, Tae-Yoon S.; Oh, Yeongju; Lee, Mirinae; Kim Taehwan Abstract: The Korean Peninsula occupies a critical part of East Asia, and thus understanding its tectonic development has a significant impact on comprehending the crustal evolution of the entire East Asia. However, there is still contention surrounding the formation of the Korean Peninsula during the Permian-Triassic collision of the SinoKorean (North China) Craton (SKC) and the South China Craton (SCC). Various hypotheses have been proposed regarding the tectonic affinity of different parts of the Korean Peninsula, complicating the proper understanding of the tectonic evolution in East Asia. This is partly due to a pre-existing geological framework that has played a pivotal role in the tectonic understanding of the Korean Peninsula, originally suggested during the age of the 'geosyncline.' This framework involves the tripartite division of the basement rocks into the Nangrim, Gyeonggi, and Yeongnam "massifs." Not bound by this pre-existing paradigm, here we provide a new perspective on the tectonic evolution of the Korean Peninsula based on multidisciplinary geological data, including paleontology, sedimentology, petrology, and geochronology. An integrative reinterpretation of the data has led to the recognition of critical insights on the development of the Korean Peninsula: (1) the Paleoproterozoic crystalline rocks of the two Gyeonggi 'blocks' were basement rocks of the SKC southern margin that were dragged down by the subduction of the eastern tip of the SCC crust during the Permo-Triassic collision and then exhumed during the Late Triassic extensional regime; (2) continental core complexes of various sizes developed near the tectonic boundaries during the Late Triassic and Cretaceous extensional regimes, resulting in the formation of coeval small non-marine basins throughout the Korean Peninsula; (3) the Cathaysia Block-affinity rocks in the midwestern part of South Korea were brought up to the surface by the Late Triassic Hongseong Core Complex, and; (4) the Hwanghae-Taean Belt around the western coast of the Korean Peninsula was formed by a Late Cretaceous 'continental crust spreading' event. Accordingly, a new subdivision of tectonic provinces of the Korean Peninsula is presented, which does not accord with the previous tectonic models that proposed either a simple collision belt running through the peninsula or the entire peninsula belonging to the SKC. We present retrograde reconstructions of the Korean Peninsula, representing the geological components from the Late Cretaceous to Permian, and integrate the results with the framework of the Permo-Triassic collision between the SKC and the SCC. Under the new perspective, geological aspects and events known in the Korean Peninsula can be revisited. Except for the northeastern terranes, the Macheollyeong Block, the Gwanmo Massif, and the Dumangang Belt, the tectonic provinces of the Korean Peninsula, from northwest to southeast, consist of the Nangrim Spread Crustal Region (SCR) (including the Pyeongnam District), Hwanghae District, Imjingang Belt, Western Gyeonggi Block, Central Gyeonggi Block, Okcheon Belt (including the Taebaeksan Complex), and Yeongnam Block. The metasedimentary rocks with the SCC-affinity in the Imjingang Belt and the Okcheon Metamorphic Belt were the Devonian-Carboniferous passive margin sediments and their substratum-forming pre-Devonian rocks in the northern margin of the SCC, which were subducted during the continental collision and exhumed in the Late Triassic. A continental arc system was formed as the SCC approached the SKC in the late Paleozoic, and the late Paleozoic Pyeongan Supergroup was formed in forearc basins developed at the southern margin of the SKC before the continental collision. The supracrustal boundary of the SKC and the SCC runs across the 'Taebaeksan Complex,' which is marked by the boundary between the SCC-derived Yeongwol Group and the SKC-derived Taebaek Group and Pyeongan Supergroup. Most importantly, the three renowned orogeni

2024-12-01T00:00:00Z Oh, Yeongju John S. Peel https://repository.kopri.re.kr/handle/201206/16262 2025-10-30T02:49:06Z 2024-11-01T00:00:00Z

Title: A new helcionelloid mollusc from the Cambrian of Greenland and Idaho (Laurentia) Authors: Oh, Yeongju; John S. Peel Abstract: Ressericonella gen. nov., a new genus of helcionelloid mollusc, characterized by a narrow shell with a shallowly convex dorsal surface and flat to shallowly concave lateral areas, is described from the Cambrian of Greenland and Idaho. The type species is Helcionella aequa Resser, 1939 from the Langston Formation (Naomi Peak Limestone Member) of early middle Cambrian age (Miaolingian Series, Wuliuan Stage, Albertella Biozone). Ressericonella pipalukae gen. et sp. nov. occurs in the latest early Cambrian (Cambrian Series 2, Stage 4, Bonnia？Pagetides elegans Biozone) of southern Freuchen Land, North Greenland. Silicified specimens of Ressericonella pipalukae from North Greenland preserve two-layered shell structure in which an inner layer with a transverse fibrous pattern similar to lamello-fibrillar structure is overlain by an outer layer with fine threads radiating from the apex.

2024-11-01T00:00:00Z