Premium
Three‐dimensional CT examination of the forefoot and hindfoot of the hippopotamus and tapir during a semiaquatic walking
Author(s) -
Endo Hideki,
Yoshida Masataka,
Nguyen Truong Son,
Akiba Yuki,
Takeda Masahiro,
Kudo Kohei
Publication year - 2019
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/ahe.12405
Subject(s) - hippopotamus , forefoot , anatomy , terrestrial locomotion , biology , medicine , zoology , complication , surgery
Semiaquatic walking has resulted in the evolution of functional and morphological changes in various hoofed mammals, such as hippopotamus and Brazilian tapir. The biomechanics of skilful walking in wetlands or at the bottom of a waterbody involve the medio‐lateral opening and closing of the feet to effectively support and stabilize the body on soft ground and to reduce the water resistance during recovery stroke, respectively. We demonstrate that the opening and closing of the feet in hippopotamus and Brazilian tapir are mediated by the adduction and abduction of the most medial and lateral phalanges from the CT examination. The axial toes, metacarpals and metatarsals do not contribute to changes in the width and shape of the feet, unlike the medial and lateral toes. We suggest that this semiaquatic walking motion is derived from the original terrestrial mode of locomotion, in contrast to the highly functional swimming motion using webs or fins in morphologically modified feet and tail. From the present data we demonstrate that semiaquatic locomotion evolved due to the acquisition of adductor–abductor mobility in the phalanges of the most medial and lateral digits, as shown in hippopotamus and Brazilian tapir.