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3. Ventral adhesive area in the limbs of walking cuttlefish (paintpot cuttlefish, Ascarosepion tullbergi): An adaptation for stable aquatic locomotion.

Author

Omura, Ayano, Takano, Haruka, Tomita, Taketeru, Yamaguchi, Tetsuo, and Oka, Shin‐ichiro

Subjects
PHYSIOLOGICAL adaptation, ANIMAL locomotion, AQUATIC animals, CUTTLEFISH, ADHESIVES, MUCUS
Abstract

Walking is a locomotion mode in which animals move over the ground using their appendages. Walking is observed in both terrestrial and aquatic animals, but the morphology and diversity of appendages in the latter group have been less extensively studied. The present paper reports on the "adhesive areas," which may represent morphological and physiological adaptations for stable aquatic walking, in the paintpot cuttlefish, Ascarosepion tullbergi. This animal employs arm IV as a forelimb and an ambulatory flap as a hindlimb for walking, resulting in a gait‐like manner of movement. The structure of the adhesive area is exclusively located on the ventral skin surface of arm IV and the ambulatory flap, which are in contact with the ground during walking. The "adhesive areas" are characterized by a dense population of adhesive mucus‐secreting cells and the development of numerous wrinkles on the surface. These features may enhance the gripping and sticking capacity of the ground‐contact area, thus improving walking stability. The use of adhesive areas for walking is a unique feature of A. tullbergi, as other cuttlefish with adhesive areas primarily use them for attaching to substrata in strong currents. Our results contribute to the understanding of the locomotion strategy of cuttlefish. [ABSTRACT FROM AUTHOR]

Published
2024
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7. IFPA meeting 2018 workshop report I: Reproduction and placentation among ocean-living species; placental imaging; epigenetics and extracellular vesicles in pregnancy

Author

Acharya, Ganesh, Bartolomei, Marisa, Carter, Anthony M., Chamley, Larry, Cotton, Charles F., Hasegawa, Junichi, Hasegawa, Yuri, Hayakawa, Satoshi, Kawaguchi, Mari, Konwar, Chaini, Magawa, Shoichi, Miura, Kiyonori, Nishi, Hirotaka, Salomon, Carlos, Sato, Keiichi, Soejima, Hidenobu, Soma, Hiroaki, Sørensen, Anne, Takahashi, Hironori, Tomita, Taketeru, Whittington, Camilla M., Yuan, Victor, and O'Tierney-Ginn, Perrie

Published
2019
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11. Absence of suction feeding ichthyosaurs and its implications for triassic mesopelagic paleoecology.

Author

Motani, Ryosuke, Ji, Cheng, Tomita, Taketeru, Kelley, Neil, Maxwell, Erin, Jiang, Da-yong, and Sander, Paul Martin

Subjects
Animals, Reptiles, Feeding Behavior, Phylogeny, Fossils, Biological Evolution, General Science & Technology
Abstract

Mesozoic marine reptiles and modern marine mammals are often considered ecological analogs, but the extent of their similarity is largely unknown. Particularly important is the presence/absence of deep-diving suction feeders among Mesozoic marine reptiles because this would indicate the establishment of mesopelagic cephalopod and fish communities in the Mesozoic. A recent study suggested that diverse suction feeders, resembling the extant beaked whales, evolved among ichthyosaurs in the Triassic. However, this hypothesis has not been tested quantitatively. We examined four osteological features of jawed vertebrates that are closely linked to the mechanism of suction feeding, namely hyoid corpus ossification/calcification, hyobranchial apparatus robustness, mandibular bluntness, and mandibular pressure concentration index. Measurements were taken from 18 species of Triassic and Early Jurassic ichthyosaurs, including the presumed suction feeders. Statistical comparisons with extant sharks and marine mammals of known diets suggest that ichthyosaurian hyobranchial bones are significantly more slender than in suction-feeding sharks or cetaceans but similar to those of ram-feeding sharks. Most importantly, an ossified hyoid corpus to which hyoid retractor muscles attach is unknown in all but one ichthyosaur, whereas a strong integration of the ossified corpus and cornua of the hyobranchial apparatus has been identified in the literature as an important feature of suction feeders. Also, ichthyosaurian mandibles do not narrow rapidly to allow high suction pressure concentration within the oral cavity, unlike in beaked whales or sperm whales. In conclusion, it is most likely that Triassic and Early Jurassic ichthyosaurs were 'ram-feeders', without any beaked-whale-like suction feeder among them. When combined with the inferred inability for dim-light vision in relevant Triassic ichthyosaurs, the fossil record of ichthyosaurs does not suggest the establishment of modern-style mesopelagic animal communities in the Triassic. This new interpretation matches the fossil record of coleoids, which indicates the absence of soft-bodied deepwater species in the Triassic.

Published
2013

24. Morphological features of the nasal cavities of hawksbill, olive ridley, and black sea turtles: Comparative studies with green, loggerhead and leatherback sea turtles

Author

Kitayama, Chiyo, primary, Ueda, Keiichi, additional, Omata, Mariko, additional, Tomita, Taketeru, additional, Fukada, Shingo, additional, Murakami, Shogo, additional, Tanaka, Yoshiaki, additional, Kaji, Akihiro, additional, Kondo, Satomi, additional, Suganuma, Hiroyuki, additional, Aiko, Yuki, additional, Fujimoto, Atsuru, additional, Kawai, Yusuke K., additional, Yanagawa, Masashi, additional, and Kondoh, Daisuke, additional

Published
2021
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26. Armored eyes of the whale shark

Author

Tomita, Taketeru, primary, Murakumo, Kiyomi, additional, Komoto, Shinya, additional, Dove, Alistair, additional, Kino, Masakatsu, additional, Miyamoto, Kei, additional, and Toda, Minoru, additional

Published
2020
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28. Etmopteridae bioluminescence: dorsal pattern specificity and aposematic use

Author

UCL - SST/ELI/ELIB - Biodiversity, Duchatelet, Laurent, Pinte, Nicolas, Tomita, Taketeru, Sato, Keiichi, Mallefet, Jérôme, UCL - SST/ELI/ELIB - Biodiversity, Duchatelet, Laurent, Pinte, Nicolas, Tomita, Taketeru, Sato, Keiichi, and Mallefet, Jérôme

Abstract

Background In the darkness of the ocean, an impressive number of taxa have evolved the capability to emit light. Many mesopelagic organisms emit a dim ventral glow that matches with the residual environmental light in order to camouflage themselves (counterillumination function). Sharks use their luminescence mainly for this purpose. Specific lateral marks have been observed in Etmopteridae sharks (one of the two known luminous shark families) suggesting an inter/intraspecific recognition. Conversely, dorsal luminescence patterns are rare within these deep-sea organisms. Results Here we report evidence that Etmopterus spinax, Etmopterus molleri and Etmopterus splendidus have dorsal luminescence patterns. These dorsal patterns consist of specific lines of luminous organs, called photophores, on the rostrum, dorsal area and at periphery of the spine. This dorsal light seems to be in contrast with the counterilluminating role of ventral photophores. However, skin photophores surrounding the defensive dorsal spines show a precise pattern supporting an aposematism function for this bioluminescence. Using in situ imaging, morphological and histological analysis, we reconstructed the dorsal light emission pattern on these species, with an emphasis on the photogenic skin associated with the spine. Analyses of video footage validated, for the first time, the defensive function of the dorsal spines. Finally, we did not find evidence that Etmopteridae possess venomous spine-associated glands, present in Squalidae and Heterondontidae, via MRI and CT scans. Conclusion This work highlights for the first time a species-specific luminous dorsal pattern in three deep-sea lanternsharks. We suggest an aposematic use of luminescence to reveal the presence of the dorsal spines. Despite the absence of venom apparatus, the defensive use of spines is documented for the first time in situ by video recordings.

Published
2019

34. A Mighty Claw : Pinching Force of the Coconut Crab, the Largest Terrestrial Crustacean

Author

Oka, Shin-ichiro, Tomita, Taketeru, and Miyamoto, Kei

Abstract

Crustaceans can exert a greater force using their claws than many animals can with other appendages. Furthermore, in decapods, the chela is a notable organ with multifunctional roles. The coconut crab, Birgus latro, is the largest terrestrial crustacean and has a remarkable ability to lift weights up to approximately 30 kg.

Published
2016

36. Locomotion is not a privilege after birth: Ultrasound images of viviparous shark embryos swimming from one uterus to the other.

Author

Tomita, Taketeru, Murakumo, Kiyomi, Ueda, Keiichi, Ashida, Hiroshi, Furuyama, Rina, and Bshary, R.

Subjects
*ANIMAL locomotion, *GINGLYMOSTOMATIDAE, *SHARKS, *AQUATIC animals, EMBRYONIC motility
Abstract

Underwater ultrasound, a new tool for observing the internal body parts of aquatic animals by scuba divers, allowed us long‐term and frequent observations of the embryos of captive aquatic vertebrates. New ultrasound data of captive tawny nurse sharks (Nebrius ferrugineus) revealed that their embryos frequently migrate between the right and left uteri during gestation. This report is the first reliable evidence of active embryonic locomotion in live‐bearing vertebrates and is contradictory to the concept of "sedentary embryo" which has mainly arisen from studies of mammals. The tawny nurse shark is unique among orectolobiform sharks, in which the embryo develops by feeding on sibling eggs in utero. Thus, we hypothesized that swimming aids in an efficient search and capture of these eggs in the uterine environment. [ABSTRACT FROM AUTHOR]

Published
2019
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37. Dental ontogeny of a white shark embryo

Author

Tomita, Taketeru, primary, Miyamoto, Kei, additional, Kawaguchi, Akira, additional, Toda, Minoru, additional, Oka, Shin-Ichiro, additional, Nozu, Ryo, additional, and Sato, Keiichi, additional

Published
2016
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44. Pectoral fin of the megamouth shark: skeletal and muscular systems, skin histology, and functional morphology

Author

Tomita, Taketeru, Tanaka, Sho, Sato, Keiichi, Nakaya, Kazuhiro, Tomita, Taketeru, Tanaka, Sho, Sato, Keiichi, and Nakaya, Kazuhiro

Abstract

This is the first known report on the skeletal and muscular systems, and the skin histology, of the pectoral fin of the rare planktivorous megamouth shark Megachasma pelagios. The pectoral fin is characterized by three features: 1) a large number of segments in the radial cartilages; 2) highly elastic pectoral fin skin; and 3) a vertically-rotated hinge joint at the pectoral fin base. These features suggest that the pectoral fin of the megamouth shark is remarkably flexible and mobile, and that this flexibility and mobility enhance dynamic lift control, thus allowing for stable swimming at slow speeds. The flexibility and mobility of the megamouth shark pectoral fin contrasts with that of fast-swimming sharks, such as Isurus oxyrhinchus and Lamna ditropis, in which the pectoral fin is stiff and relatively immobile.

Published
2014

48. Evolutionary Relations of Hexanchiformes Deep-Sea Sharks Elucidated by Whole Mitochondrial Genome Sequences

Author

Tanaka, Keiko, primary, Shiina, Takashi, additional, Tomita, Taketeru, additional, Suzuki, Shingo, additional, Hosomichi, Kazuyoshi, additional, Sano, Kazumi, additional, Doi, Hiroyuki, additional, Kono, Azumi, additional, Komiyama, Tomoyoshi, additional, Inoko, Hidetoshi, additional, Kulski, Jerzy K., additional, and Tanaka, Sho, additional

Published
2013
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