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| Tacola kamitanii Aiba, Takahashi & Saito, 2025 |
Abstract
This study describes a new fossil butterfly species, Tacola kamitanii sp. nov., from the Upper Pliocene to the Lower Pleistocene Teragi Group in Hyogo Prefecture, Japan. The new fossil is characterized by remarkably large wings, with an estimated forewing length of 48 mm and a wingspan of 84 mm. This new fossil species belongs to the genus Tacola based on the following characteristics: both discal cells open, smoothly curved humeral veins, and a thick thorax and abdomen. However, it does not identify with any modern relatives of Tacola with a small discal cell, straight 1A+2A anal vein of the forewing, or long hindwing median vein. Therefore, the fossil was identified as a new species of the genus Tacola and one of the largest species in the subfamily Limenitidinae. The modern relatives of Tacola are distributed in the subtropics and tropics, while this fossil species may have survived in the temperate zone. This is the first named Limenitidini fossil and the youngest example of an extinct butterfly.
Keywords: butterfly fossil, fossil insect, Haruki Mudstone, Limenitidini, Tacola, Teragi Group
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| Photographs of Tacola kamitanii sp. nov., holotype, SOU-001. A, ventral side, SOU-001-A; B, dorsal side, SOU-001-B. |
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| Reconstruction of Tacola kamitanii sp. nov. and comparison with extant species. A, habitus of Neptis alwina (Nagano Pref., Koumi machi, Japan. VII. 1992). B, forewing of N. alwina. C, hindwing of N. alwina. D, habitus of Athyma perius (Da Nang. City, Vietnam, VIII, 2014). E, forewing of A. perius. F, hindwing of A. perius. G, habitus of Tacola larymna (Ho Chi Minh, south Vietnam, IX, 2003). H, forewing of T. larymna. I, hindwing of T. larymna. J, habitus of Tacola kamitanii sp. nov. The dotted line area was estimated with reference to the forewing morphology of T. larymna (type species of the genus Tacola). K, forewing of T. kamitanii sp. nov. L, hindwing of T. kamitanii sp. nov. The blue arrows indicate contact point of vein M3 and vein CuA1. The green arrows indicate anal vein 1A+2A. The red arrows indicate humeral vein. Fossil wing length and general shape were estimated based on the wing proportions of T. larymna. Scale bar: 1.0 cm. |
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| G, habitus of Tacola larymna (Ho Chi Minh, south Vietnam, IX, 2003). H, forewing of T. larymna. I, hindwing of T. larymna. J, habitus of Tacola kamitanii sp. nov. The dotted line area was estimated with reference to the forewing morphology of T. larymna (type species of the genus Tacola). K, forewing of T. kamitanii sp. nov. L, hindwing of T. kamitanii sp. nov. The blue arrows indicate contact point of vein M3 and vein CuA1. The green arrows indicate anal vein 1A+2A. The red arrows indicate humeral vein. Fossil wing length and general shape were estimated based on the wing proportions of T. larymna. Scale bar: 1.0 cm. |
Order Lepidoptera Linnaeus, 1758
Superfamily Papilionoidea Latreille, 1802
Family Nymphalidae Rafinesque, 1815
Subfamily Limenitidinae Behr, 1864
Tribe Limenitidini Behr, 1864
Genus Tacola Moore, 1898
Tacola kamitanii sp. nov.
[New Japanese name: Kamitani-onimisuji]
Diagnosis.—Large nymphalid butterfly (estimated forewing length 48 mm, estimated wingspan 84 mm). Both wings with completely open discal cells. Forewing discal cell relatively small. The forewing has cell streaks and an upper postdiscal band with a straight anal vein 1A+2A. Vein R2 arises from the cell. Hindwing has smoothly curved humeral vein and longer vein M. Thorax and abdomen thick.
Type locality and horizon.—The Umigami, Shin’onsen Town, Hyogo Prefecture, Japan (Figure 1). However, exact locality remains unknown. Based on the lithofacies of tuffaceous siltstone, the stratigraphic horizon is correlated with the Upper Pliocene to Lower Pleistocene, Haruki Mudstone of the Teragi Group (Kinugasa, 1981; Kamitani, 1990).
Etymology.—After Kiyoshi Kamitani, a fossil collector.
Hiroaki Aiba, Yui Takahashi and Kotaro Saito. 2025. New Species of fossil Butterfly (Nymphalidae: Limenitidinae) from the Upper Pliocene to Lower Pleistocene Teragi Group, Hyogo Prefecture, Japan. Paleontological Research. 29; 76-86. DOI: doi.org/10.2517/prpsj.240023
