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Honors Thesis Archive

Author Brenna Burkhart
Title Ultrastructure of Spermiognesis in the Yellow-Bellied Sea Snake, Pelamis platurus(Squamata: Elapidae: Hydrophiinae)
Department Biology
Advisors Kevin Gribbins, Michelle McWhorter, and Barbara Austin
Year 2013
Honors University Honors
Full Text View Thesis (326 KB)
Abstract Within the order Squamata, only a few studies have been completed on the morphological characteristics of developing spermatids as they undergo spermiogenesis, including a recent study in 2010 on Cottonmouths (Gribbins, et al., 2010). To date there have been no studies on the spermiogenesis within the sea snakes of the subfamily Hydrophiinae that consists of 17 genera and 62 species of venomous snakes. Testicular tissue samples of three male Pelamis platurus were captured in Costa Rica in July of 2009. Cellular analysis, through the use of light and transmission electron microscopy, was performed on developing spermatids in the three phases of spermiogenesis: acrosome formation, nuclear elongation, and chromatin condensation. Transmission electron microscopy was used to determine the ultrastructure of these sperm cells for comparison with the other snakes studied to date. Spermatids of P. platurus possesses some notable differences such as a more prominent central lacuna in the nucleus, radiating arrays of the outer longitudinal manchette microtubules, and a shorter epinuclear lucent zone when compared to the Cottonmouth and other snakes studied to date. The majority of the spermatid morphology is conserved during the phases of spermiogenesis. The minute differences that do exist in the Yellow-bellied Sea Snake spermatids may help us understand the phylogenetics and evolution of aquatic snakes from their terrestrial ancestors. However, data on snake spermatids is lacking at this time and many more species of snakes have to be studied before we have a robust understanding of spermiogenesis in the taxa of squamates.

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