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.

The morphological characters of the male external genitalia of the European hedgehog (Erinaceus Europaeus)

“…The researchers of the study reported that the glandular tissue in the penile bulb was surrounded by the penile corpus spongiosum, which is not in line with the finding about the European hedgehog. Moreover, the lack of the penile corpus spongiosum in the bulb and body of the penis and existence of glans corpus spongiosum which not surrounded the urethra are dissimilar to findings in porcupine [5], male rat and male mouse [10], and Asian musk shrews (Suncus murinus) [20].…”

“…They were situated dorsolaterally to the penis in this animal and extended to the end of the penile body. In this case, European hedgehogs resemble Asian musk shrews (Suncus murinus) [20].…”

Nitrosative protein tyrosine modifications: biochemistry and functional significance

“…12 in plasma (32). Today, instrumental and technological advances, including bioinformatics tools and mass spectrometry, make it possible to analyze crude proteome mixtures and thousands of proteins simultaneously.…”

Molecular genetic cascades for external genitalia formation: An emerging organogenesis program

“…Regarding tail development, the tail gut, namely the endodermal organ connected to the cloaca, is prominently observed during mouse development (Suzuki et al, 2004a). Apart from such early urogenital developmental divergences, the mature human penis develops no penile bones in contrast to the murine penis (Murakami and Mizuno, 1986;Murakami, 1987;Yamada et al, 2003;Kamikawa-Miyado et al, 2005).…”