Article

A new species of Acer samaras from the Miocene Yeonil Group in the Pohang Basin, Korea

Geosciences Journal (Impact Factor: 0.52). 11/2008; 12(4):331-336. DOI: 10.1007/s12303-008-0033-6

ABSTRACT Acer pohangense sp. nov. belonging to Aceraceae is described based on the six detached samaras collected from the Duho Formation of the Miocene
Yeonil Group. This species is characterized by its comparatively large-sized samara with a wing and seed, and its wide divergent
angle. The occurrence of such a large-sized samara is the first on record not only in the Korean Tertiary floras, but also
in the East Asian Tertiary floras.

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    ABSTRACT: A total of 16 specimens of fossil-winged fruits were found from the Middle Miocene marine deposits, Duho Formation, Pohang Basin, Korea. They were identified into two structurally different groups: 15 specimens into a winged fruit of Fraxinus, and one specimen of Liriodendron. The most samaras (13 specimens) were identified as Fraxinus oishii, which is characterized by narrowly ovate or ovate–elliptic shapes that are 2.7–3.6 cm in length and 0.7–1 cm in width (l/w ratio=3.4–4). The apexes of the Fraxinus oishii samara are round or slightly emarginated, and a seed of the samara is always located at the base, of which the general shape is narrow rhombic-ellipsoidal. The seed is 1.2–2 cm long and 0.5–0.7 cm wide. Two specimens are different from the samara of Fraxinus oishii. They have a 6.6 length/width ratio (3.3 cm long and 0.5 cm wide), and thus, are temporarily classified into the Fraxinus sp. One specimen was recognized as a winged seed of Liriodendron meisenense. The wing is broadly lanceolate to elliptic in shape, has a smooth, acute apex, and is approximately 3 cm long and 0.7 cm wide. Samaras of Fraxinus oishii and Liriodendron meisenense were early reported from the Middle Miocene deposits from North Korea, but these specimens are the first discovery in South Korea. Further study of the Duho Formation may connect flora relationships between North and South Korea.
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