Glans inflation morphology and female cloaca copulatory interactions of the male American alligator phallus.
Biol Reprod
; 104(2): 374-386, 2021 02 11.
Article
em En
| MEDLINE
| ID: mdl-33112370
ABSTRACT
The phallic glans of the American alligator (Alligator mississippiensis) is the distal termination of the semen-conducting sulcus spermaticus and during copulation has the closest, most intimate mechanical interactions with the female urodeum, the middle cloacal chamber that contains the opening to the vaginal passages and oviducts. However, the details of this interface leading to insemination and gamete uptake are unclear. Here, we (1) histologically characterize the underlying tissue types and morphologically quantify the shape changes associated with glans inflation into the copulatory conformation, (2) digitally reconstruct from MRI the 3D shape of functional tissue compartments, and (3) diffusible iodine-based contrast-enhanced computed tomography image the copulatory fit between male phallus and female cloaca. We discuss these results in relation to tissue type material properties, the transfer on intromittent forces, establishing potential copulatory lock, inflated glans volume scaling with body mass/length, the mechanics of semen targeting and insemination, and potential female cryptic choice impacting multiple clutch paternity. In part, this study further clarifies the phallic morphological variation observed among crocodylians and begins to investigate the role(s) these divergent male forms play during copulation interacting with female cloacal forms to increase reproductive success.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Pênis
/
Cloaca
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Copulação
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Jacarés e Crocodilos
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article