title: The morphological and histological characters of the male external genitalia of the house musk shrew, Suncus murinus.
abstract: External genitalia are the reproductive organs necessary for efficient copulation and internal fertilization in various mammalian species. Their morphogeneses display significant morphological and developmental differences among species. The house musk shrew, Suncus murinus (hereafter described as suncus) is a species of the order Insectivora, which has been considered as primitive and one of the earliest eutheria phylogenetically. Comparative anatomical analyses of phylogenetically different mammals will contribute to the better understanding of morphological diversity of external genitalia. This study performed various anatomical and histological analyses concerning the organization of the external genitalia of male suncus. It was shown that the external genitalia of suncus possessed a muscular structure, which we proposed as musculus ischiocavernosus dorsalis of suncus. The musculus ischiocavernosus dorsalis is originated from the inner surface of the tuber ischiadicum and was allocated adjacent to the corpus cavernosum penis. In addition, a pair of alpha-smooth muscle actin positive muscles was located bilaterally to the urethra. This unique morphology of the external genitalia of suncus males may provide a unique model system to investigate genital morphogenesis.
authors.affiliation: Center for Animal Resources and Development (CARD) and Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Honjo, Kumamoto, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Kamikawa-Miyado
authors.forename: Hidenao
authors.initials: H
authors.lastname: Ogi
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ogino
authors.forename: Hironori
authors.initials: H
authors.lastname: Katoh
authors.forename: Kentaro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Masanori
authors.initials: M
authors.lastname: Uemura
authors.forename: Junzoh
authors.initials: J
authors.lastname: Kitoh
authors.forename: Sen-Ichi
authors.initials: S
authors.lastname: Oda
authors.forename: Gen
authors.initials: G
authors.lastname: Yamada
mesh_terms: D000717:Anatomy, Comparative; D000818:Animals; D005837:Genitalia, Male / Q000033:anatomy & histology* / Q000254:growth & development; D006652:Histological Techniques; D007150:Immunohistochemistry; D008297:Male; D009024:Morphogenesis; D012788:Shrews / Q000033:anatomy & histology*; D013045:Species Specificity