Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Haruyoshi Maeda Last modified date:2024.03.12

Professor / Graduate School of Science, Earth and Planetary Sciences, Paleontology and Mineralogy / The Kyushu University Museum


Presentations
1. Maeda, H., Tanaka, G., Nenoki, K., Kase, Y., and Ito, Y., Fossil preservation of luminous organs of Miocene deep-sea fishes from Chita Peninsula, central Japan, 2nd Asian Paleontological Congress, 2023.08, The Miocene Morozaki Group on the Chita Peninsula, Aichi Prefecture, Japan, is rich in fossils of a variety of deep-sea faunas. Many of the remains, buried in volcaniclastic rocks, have preserved their soft parts, forming unique fossil-Lagerstätten. Among them, the fossils of the lantern fishes (Myctophiformes) from the tuffaceous sandstone beds are unique because they retain the luminous organs characteristic of deep-sea fishes. The luminous organs of lantern fishes consist of four main components: (1) photocytes, (2) tapetum, (3) pigments, and (4) scales on the surface that act as a protective lens. The luminous organs are so delicate that they were expected to decay and disintegrate quickly after death, and it was thought that they would not remain as fossils. However, in the Morozaki Group, a distinct row of luminous organ units, each 0.5 to 1.5 mm in diameter, is clearly observed along the ventral side of the fossil fish body. Further examination revealed that the internal structure and morphology of the luminous organs remained intact at the electron microscopic scale. SEM observations showed that tapeta, each about 15 µm in diameter, were neatly arranged in the space beneath the scales, like tiles were laid on top of each other, forming a concave reflection mirror as a whole. In addition, spherical to ellipsoidal pigment particles of about 1 µm in diameter are densely packed and line the tapeta. Fossils show the same structure as the luminous organs of living lantern fish.
TOF-SIMS analysis of the fossil luminous organs revealed the presence of guanine, which was originally abundant in the pigment, as well as CN, CNO, C2x-1N, and C3NO. This means that not only the morphology but also fragments of the original chemical substances that made up the luminous organs may have been preserved in the fossil. In addition, ultraviolet and infrared photographic observations have shown that soft tissues of lantern fishes, such as eyes, muscles, and peritoneum, are also preserved as flattened black masses or thin films. To verify the early fossilization process, we are currently carrying out decomposition experiments on the remains of the modern lantern fish and other species to compare with fossil preservation. As they decay, the remains become like a skin pouch with bones and skin remaining, and the fossils were found to be preserved in a similar state in the Morozaki Group.The occurrence of deep-sea fossil-Lagerstäten in younger age volcaniclastic rocks is a geological phenomenon unique to mobile belts such as Japan. They are rarely found in Western Europe, and have not been identified as targets for "fossil-Lagerstätten" research. In this context, the deep-sea fossil assemblages of the Morozaki Group are very unique..
2. Yoshinaga, K., Hirose, K, and Maeda, H., Taxonomy and Paleoecology of Nipponitrigonia from the mid-Cretaceous Goshoura Group, Kyushu, Japan, 2nd Asian Paleontological Congress, 2023.08, Nipponitrigonia is a unique bivalve that inhabited in upper shoreface environment, where the other bivalves had been absent. Eight species of Nipponitrigonia occur from the upper Jurassic and the Cretaceous System in Japan. For example, N. kikuchiana showing butterfly position occurs frequently from the shoreface deposits in the Lower Aptian Tanohata Formation, Miyako Group, intercalating tsunami deposit. Six Nipponitrigonia species occur from the Upper Jurassic to the Lower Cretaceous. On the other hand, two species are known to occur from the mid-Cretaceous Goshoura Group exposed in the Goshoura-jima and Shishi-jima islands, Kyushu, Japan. These two species have not yet been studied in detail so that the post-Albian evolutionary history of Nipponitrigonia remains unclear. The paleoecology of Nipponitrigonia has been estimated by various studies, however these estimates are not necessarily substantiated by the actual modes of fossil occurrence. We focus on the Upper Cretaceous Nipponitrigonia species from the Goshoura Group and discuss the stratigraphic range, and paleoecology based on individuals buried in situ.
Nipponitrigonia from the Goshoura Group is identified as “Nipponitrigonia sp. nov.” reported preliminarily by Hirose. It is characterized by smooth shell-surface ornamentation without any concentric costae on the near umbo and anterior part of the shell surface compared with the other species and strong shell inflation. On the other hand, less-inflated individuals show sympatric occurrence together with the inflated ones. We measured shell inflation (T/L ratio) “Nipponitrigonia sp. nov.” As a result, the distribution of the T/L ratios shows a continuous and unimodal pattern, which cannot be divided. Difference of the shell-inflation in “Nipponitrigonia sp. nov.” is intraspecific variation. The species occurs from the Graysonites adkinsi-Desmoceras kossmati Zone correlated to the lowermost Cenomanian. In addition, “Nipponitrigonia” sp. from the Turonian of Kochi district is also assignable to the same species. The stratigraphic range of “Nipponitrigonia sp. nov.” is possibly prolonged to the Turonian. The present species occurs from gravelly sandstone and conglomerate in upper shoreface, in which the valves are usually found disarticulated. We discovered 5 still-articulated individuals. Among them, burial orientations of 3 individuals (direction and plunge angles of the commissure planes and carina) are measured in situ. They raise their back edge of area upward, and the plunge angles after tilt collection are approximately 10 to 20 degrees to the bedding. This burial position is similar to that of living Neotrigonia species, and these individuals seemed to be buried in situ in such a high energy depositional environment. Nipponitrigonia tends to lose shell ornamentation stratigraphically, and “Nipponitrigonia sp. nov.” is the last representative of the genus as far as known..
3. Matsuguma, Y., Ito, Y., Maeda, H., and Oyama, N., The Lower Carboniferous brachiopods from the Akiyoshi Limestone Group, Southwest Japan, 2nd Asian Paleontological Congress, 2023.08, The Akiyoshi Limestone Group, the Late Paleozoic seamount deposits, is exposed in Mine, Yamaguchi, southwest Japan, and extends about 15 km from east to west and 8 km from north to south. Most of the group consists of pure, non-laminated limestone and contains many shallow-sea fossils from the Early Carboniferous to the Middle Permian. These fossils consist mainly of corals, crinoids, foraminifers and brachiopods, and these organisms formed an organic reef complex, at least during the Carboniferous Period. Of these fossils, brachiopods are considered particularly useful for paleobiogeographic studies due to their abundance and low mobility. However, there has been no detailed taxonomic study of the brachiopos in this group since the work of Juichi Yanagida and others in the 1990s, and there are are no such applied studies because the entire brachiopod assemblage has not yet been clarified. In this study, we carried out a long-term field survey of the Lower Carboniferous brachiopod fossils to provide a more detailed taxonomic study of the fossils. As a result, many previously undescribed species were identified, and new fossil localities were found.
In this study, brachiopod fossils were collected from Mt. Ohira and the Koishidao area, located in the southwestern part of the Akiyoshi Limestone Group. In Mt. Ohira, the Endothyra Zone (Visean) to the Pseudostaffella minuta Zone(Bashikirian) are distributed, and many brachiopod fossils were collected especially from the Millerella yowarensis Zone (Serpukhovian). These fossils consist of Purdonella sp., Linoproductus sp. A and Schizophoria sp. A. On the other hand, the Nagatophyllum satoi Zone (Visean) is distributed in the Koishidao area, and Latiproductus sp., Schuchertella? sp., Dictyoclostidae gen. sp. indet., Marginatia sp., Linoproductus sp. B, Schizophoria sp. B and Elythidae gen. sp. indet. have been found in this biozone. The limestone containing the brachiopod fossils consists of crinoidal grainstone and is poorly sorted in both areas, and coral fossils are often found near brachiopod fossil sites. This situation suggests that these fossil localities were close to the reef and had high energy levels. Of these fossils, Purdonella sp., Linoproductus sp., Schizophoria sp. A and Dicthyoclostidae gen. sp. indet. are species not previously described from the Akiyoshi Limestone Group, and the genus Marginatia had previously only been found below the lower than Nagatophyllum satoi Zone. These results indicate that the brachiopod fossil assemblage of this group is more diverse than previously thought. In the future, we plan to carry out more detailed taxonomic studies, including observations of internal structures, and to consider the paleobiogeographic significance of these fossil assemblages..
4. Sato, S. and Maeda, H., Modes of ammonoid occurrence and preservation of the Bajocian (Middle Jurassic) Tsunakizaka Formation in the Miyagi prefecture, Japan, 2nd Asian Paleontological Congress, 2023.08, The Tsunakizaka Formation, the Middle Jurassic Karakuwa Group is widely distributed in the Kesennuma district, Miyagi Prefecture, northeastern Japan. The formation is a rare example that yields rich Bajocian ammonoid fauna in Japan. The fauna includes Stephanoceras cf. plicatissimum, Sonninia cf. corrugata, Witchellia cf. pelekus, Stirogoceras cf. languidum. Stephanoceras cf. plicatissimum, and Emileia sp. These ammonoid fossils are found sporadically, buried horizontally in weakly laminated mudstone, and are flattened and also slightly distorted by compaction and subsequent tectonic shear. Despite of such deformity, they are usually found as complete whorls, and their morphologic features, e.g. shell-ornament, are well observable. The traditional fossil site (Site 2) has been covered with concrete and are now inaccessible. Recently the various Bajocian ammonoid fossils collected from the Site 2 before the construction were donated to the Kyushu University Museum by Yoshitaka Matsui (“the Matsui Collection”).
On the other hand, Holcophylloceras sp. has involute whorls with wider umbilicus, sigmoidal ribs on outer half of whorl, and prominent, deep, strongly curved, falcoid, falcate or angled constrictions on surfaces of shell. Compared with the other ammonoids mentioned above, Holcophylloceras sp. tends to occur from different lithofacies, i.e., medium grained sandstone beds (3 cm thick) intercalated with thick sandy mudstone at the new fossil site we discovered (Site 1). Stephanoceras sp., Sonninia sp., bivalves and plant fragments occur as associated fossils. Holcophylloceras sp. accounts for 46 of the 52 ammonoid fossils from the Site 1.Among 46 Holcophylloceras individuals, the ten keep their body chambers, while the other 36 individuals occur as fragmented pieces of phragmocones or body chambers. Holcodiscus sp. are rather rare in previous fossil sites composed of fine grained deposits. In all, only two individuals of Holcophylloceras sp. were included in the Matsui Collection consisting of 127 specimens. Stratigraphically, Sites 1 and 2 are almost the same level. Such difference in modes of fossil preservation is attributable to differences in taphonomic processes. Ammonoid carcasses would have been sunk to quiet mud bottom at the Site 2. Contrary, empty shells of Holcophylloceras sp. could be transported by sediment-gravity flow, and must have suffered serious damage during transport..
5. Preservation of soft-tissues (especially luminous organs) of fossil lantern fish from the Miocene Morozaki Group.
6. Occurence of Nipponitrigonia from the Upper Cretaceous System.
7. Comparison of sedimentary facies and insect fauna of the new outcrop including fossil insects from the Upper Triassic Mine Group.
8. Sedimentary facies of the new outcrop including fossil insects from the Upper Triassic Mine Group.
9. Multiple shell-forming failure in an ornamented ammonoid, “Yubariceras” sp. (Ammonitida, Acanthoceratidae) found from the Cretaceous Yezo Group, Hokkaido, japan.
10. Disease never come singly: pathological case study on a Cretaceous ammonoid Menuites japonicus from Hokkaido, Japan.
11. Morphological and taxonomic study of the subfamily Madygellinae from the Upper Triassic Mine Group..
12. Classification of the primitive Hymenoptera (Symphyta, Xyelidae, Madygellinae) from the Upper Triassic Mine Group, southwest Japan..
13. Oyama, N. and Maeda, H., Discovery of primitive Hymenoptera from the Upper Triassic Mine Group, southwest Japan, International Symposium and Workshop on Karst Science and Geopark, 2018.03, Many insect fossils occur from the Upper Triassic Mine Group, a marine and non-marine thick clastic sequence during Carnian-Norian time. They are the oldest records of insects in Japan and are also rare examples in the East Asia. Until now, fourteen orders (Coleoptera, Blattaria, Hemiptera, Mecoptera, Orthoptera, Hymenoptera, Ephemeroptera, Neuroptera, Perlida, Protorthopter, Trichoptera, Odonata, Diptera, Emdioptera?) have been recovered from the Hirabara (marine) and Momonoki (non-marine) formations. Among them, fossil sawflies in the Hymenoptera represent the early evolutionary history of this order in Triassic period, and genus Archxyela, Asioxyela, Lithoxyela, Madygella, Potrerilloxyela and Samarkandykia of family Xyelidae are newly identified. Besides isolated wings, several individuals still keep intact body parts like appendages and ovipositors. Discovery of family Xyelidae is the second oldest record in Laurasia, and suggest that they had already been diversified in Laurasia during Triassic period..
14. Challenge of taphonomy originating from ammonoid-fossil research.
15. Taphonomy of Psiloceras shells occurring just above the T/J boundary in the Muller Canyon Section, Nevada, USA..