Language：Japanese   Publisher：名古屋大学博物館  

コロナ禍による臨時休館時に，博物館オリジナルの教育コンテンツを市民に届ける方法として，博物館ウェブサイトに新しいページ「おうちで名大博物館」を新規掲載した．「おうちで名大博物館」に掲載するコンテンツは6つとし，(1)館内のようす（ドローン動画），(2)博物画を知ろう，(3)常設展示紹介動画「ホンモノに会おう」，(4)野外観察園だより，(5)よみもの，(6)ホネパズルの6つとした．

DOI： 10.18999/bulnum.037.03

CiNii Books

Authorship：Last author   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

The cetaceans display a wide variety of lifestyles, especially with regard to their feeding behavior. However, the evolutionary process of the feeding behavior in cetaceans is still poorly understood, in part because reconstructing the feeding behavior of extinct taxa remains difficult. In cetaceans, cranium mobility relative to the trunk largely depends on the range of motion permitted by the atlanto-occipital joint, given the lack of flexibility of the cervical series. In this study, we examined 56 extant cetacean skeletal specimens from 30 species in 25 genera and nine families in order to investigate the relationships between anatomical traits and feeding behavior. Our results suggest that the range of dorso-ventral motion allowed by the atlanto-occipital joint (ROM) depends on prey habitat and the feeding technique of cetaceans. Cetaceans feeding on benthic/demersal prey had a relatively large ROM compared with those feeding on pelagic prey. In addition, ROM was largest in raptorial feeders, intermediate in suction feeders, and smallest in ram-filter feeders. Among raptorial feeders, ROM tended to be larger in taxa that facultatively tear off the prey's flesh compared with taxa that swallow their prey whole. Therefore, we conclude that ROM is a powerful tool to reliably reconstruct the feeding behavior of extinct cetacean taxa.

DOI： 10.1111/joa.13111

Web of Science

PubMed

Authorship：Last author   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

The upper beak bone of birds is known to be overlain by the rhinotheca, which is composed of the horny sheath of keratinous layers. However, the details of the structure and growth pattern of the rhinotheca are yet to be understood. In this study, the microstructure of the rhinotheca from chicken specimens of different growth stages (ranging from 1 to ~ 80 days old) was analyzed using a combination of thin section and scanning electron microscopy observations, and small-angle X-ray scattering analysis. We found that the rhinotheca comprises three different layers - outer, intermediate, and inner layers - throughout its growth. The outer layer arises from the proximal portion of the beak bone and covers the dorsal surface of the rhinotheca, whereas the intermediate and inner layers originate in the distal portion of the beak bone and underlie the outer layer. This tri-layered structure of the rhinotheca was also observed in wild bird specimens (grey wagtail, king quail, and brown dipper). On the median plane, micro-layers making up the outer and inner layers are bedded nearly parallel to the rostral bone at the base. However, more distally positioned micro-layers of the outer layer are more anteverted distally. The micro-layers of the intermediate layer are bedded nearly perpendicular to those of the outer and inner layers on the median plane. The growth of micro-layers in the intermediate layer adds thickness to the rhinotheca, which causes the difference in profile between the beak bone and the rhinotheca in the distal portion of the beak. Moreover, the entire intermediate layer grows distally as new proximal micro-layers form. The outer layer is dragged distally by the intermediate layer as a result of its distal growth, for the three layers are closely packed to each other at their boundaries. Furthermore, the occurrence of the intermediate and inner layers in the distal portion of the rostral bone may be because the distal end of the beak is frequently used and worn, and the rhinotheca therefore needs to be replaced more frequently at the distal end. The rhinotheca structure described here will be an important and useful factor in the reconstruction of the beaks of birds in extinct taxa.

DOI： 10.1111/joa.12998

Web of Science

PubMed

Web of Science

Web of Science

Web of Science

Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

The diameter and vertical depth of sand crab tunnels in sandy beaches are usually restricted to a few centimeters scale and several tens of centimeters, respectively. We designed a study to determine what physical factors restrict tunnel diameter and predict the maximum attainable tunnel diameter and depth. We collected field data on the size and spatial distributions of ghost crab (Ocypode spp.) burrows on two sandy beaches (Kawage Beach in Tsu, Mie Prefecture, Japan and Sakieda Beach in Ishigaki, Okinawa Prefecture, Japan), where O. ceratophthalma dominants the ghost crab fauna. We measured burrow depths and distance from shoreline in concert with water content of sandy beaches. To explain our observed distributions of crab burrows in the field, we performed experiments in a lab microcosm, comprising a horizontal tunnel through wet sand. We measured the static stability of tunnel structures in relation to water content and two strengths computed from loading force exerted on the sand overlying the tunnels. By comparing field and experimental data, we found that crabs construct their burrows in appropriately wet zones (wet enough to provide sufficient cohesion of the sand grains in tunnel walls to prevent collapse) and that tunnel diameters and depths are sufficiently small to prevent deformation and collapse of their tunnels.

DOI： 10.1371/journal.pone.0215743

Web of Science

Language：Japanese   Publisher：The Society of Powder Technology, Japan  

<p>Empirical forms for the strengths characterizing stability of a horizontal tunnel in wet granular matter are experimentally derived. The motivation of this study comes from the observation of crab burrows on sandy beach. To understand the mechanical constraints for constructing the stable burrow structures, we perform a set of simple experiments with a horizontal tunnel structure made in a wet granular layer. Then, the tunnel is compressed from the top of the layer using a universal testing machine. During the compression, the shrinking tunnel shape is captured by a camera. Using the measured compression force, stroke, and shrinking tunnel images, we define and measure the mechanical strengths of wet granular matter with a horizontal tunnel. By systematically varying the experimental conditions, we obtained the empirical forms for estimating strength values. Using the measured results, we briefly discuss the mechanical conditions of sandy crab burrows.</p>

DOI： 10.4164/sptj.56.194

CiNii Books

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Cohesive granular matter can support stable void structures, which can universally be found in various scenes from everyday lives to space. To quantitatively characterize the stability and strength of a void structure in cohesive granular matter, we perform a simple tunnel-compression experiment with wet granular matter. In the experiment, a horizontal tunnel in a wet granular layer is vertically compressed with a slow compression rate. The experimental result suggests that the tunnel deformation can be classified into the following three types: (i) shrink, (ii) shrink with collapse, and (iii) subsidence by collapse. Using the experimental result, we estimate the stable limit of various void structures in a cohesive granular layer from crab burrows on a sandy beach to the pits observed on cometary surfaces.

DOI： 10.1038/s41598-018-33978-8

Web of Science

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Deducing the scapular positions of extinct tetrapod skeletons remains difficult, because the scapulae and rib cage are connected with each other not directly by skeletal joint, but by thoracic muscles. In extant non-testudine quadrupedal tetrapods, the top positions of the scapulae/suprascapulae occur at the anterior portion of the rib cage, above the vertebral column and near the median plane. The adequacy of this position was tested using three-dimensional mechanical models of Felis, Rattus and Chamaeleo that assumed stances on a forelimb on a single side and the hindlimbs. The net moment about the acetabulum generated by the gravity force and the contractive forces of the anti-gravity thoracic muscles, and the resistance of the rib to vertical compression between the downward gravity and upward lifting force from the anti-gravity thoracic muscle depend on the scapular position. The scapular position common among quadrupeds corresponds to the place at which the roll and yaw moments of the uplifted portion of the body are negligible, where the pitch moment is large enough to lift the body, and above the ribs having high strength against vertical compression. These relationships between scapular position and rib cage morphology should allow reliable reconstruction of limb postures of extinct taxa.

DOI： 10.1111/joa.12778

Web of Science

PubMed

Authorship：Last author   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

The beak has independently been evolved accompanied by the edentulism in many tetrapod linages, including extant Testudinata and Aves, and its form and function have been greatly diversified. The beak is formed by beak bones and the overlying keratinous cover, although their profiles are different from each other. Therefore, it is difficult to reliably reconstruct the entire profile of the beak in extinct taxa, whose keratinous tissues are rarely preserved. For elucidation of the morphological relationship between beak bone and overlying keratinous cover, we compared the curvature distribution of the culminal profiles of the upper beak bone and the overlying keratinous cover (rhinotheca) with each other using CT-scan, in 66 extant testudinatan and avian specimens (Aves: 33 genera, 24 families; Testudinata: 12 genera seven families). In both, rhinotheca and beak bone, the curvature of the profile was nearly constant rostral to a certain point, which was defined as the transition point, and the transition points of the rhinotheca and beak bone were close to each other. The profiles of the rhinotheca and beak bone rostral to their transition point were different in curvature and length. However, the ratio between the curvatures of rhinotheca and the beak bone strongly correlated with the arc angle of the rostral culminal profiles of the beak bone. The upper beak profile in extinct taxa is expected to be reconstructed more reliably using the abovementioned relationship between the beak bone and the rhinotheca.

DOI： 10.1002/jmor.20799

Web of Science

PubMed

Language：Japanese   Publisher：Palaeontological Society of Japan  

We propose a new method of embedding animal samples in epoxy resin Devcon ET (Illinois Tool Works Inc.). This new method provides simultaneous observations of hard and soft tissues of extant animals on thin sections. Comparing to methods previously proposed, our method has advantage that the resin is inexpensive, colorless and transparent. The procedure is; (1) dehydrate the formalin-fixed samples sufficiently with acetone; (2) impregnate the sample with a heated mixed solution of Devcon ET and 99.8 % acetone under reduced pressure; (3) impregnate the sample with Devcon ET under reduced pressure and heat it until the resin cures. The second procedure enables to lower the viscosity of the resin. By this method, it became possible to make colorless transparent biological thin sections at low cost. The sample should more effectively be impregnated by the resin with a longer period of the dehydration and drilling of small holes on the surface.

DOI： 10.14825/kaseki.103.0_51

CiNii Books

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/joa.12518

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/jmor.20573

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1098/rspb.2012.0190

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/jmor.10846

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1671/039.029.0406

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/jmor.10744

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/jmor.10748

Language：English   Publishing type：Research paper (scientific journal)  

Total pages：189   Language：English

Language：Japanese

Language：Japanese

Language：Japanese

CiNii Books

Language：Japanese

Total pages：540p   Language：Japanese

CiNii Books

Total pages：435   Language：Japanese Book type：General book, introductory book for general audience

Total pages：396   Language：Japanese Book type：Textbook, survey, introduction