Initial collection, characterization, and storage of tuatara (Sphenodon punctatus) sperm offers insight into their unique reproductive system

PLoS One. 2021 Jul 8;16(7):e0253628. doi: 10.1371/journal.pone.0253628. eCollection 2021.

Abstract

Successful reproduction is critical to the persistence of at-risk species; however, reproductive characteristics are understudied in many wild species. New Zealand's endemic tuatara (Sphenodon punctatus), the sole surviving member of the reptile order Rhynchocephalia, is restricted to 10% of its historic range. To complement ongoing conservation efforts, we collected and characterized mature sperm from male tuatara for the first time. Semen collected both during mating and from urine after courting contained motile sperm and had the potential for a very high percentage of viable sperm cells (98%). Scanning electron microscopy revealed a filiform sperm cell with distinct divisions: head, midpiece, tail, and reduced end piece. Finally, our initial curvilinear velocity estimates for tuatara sperm are 2-4 times faster than any previously studied reptile. Further work is needed to examine these trends at a larger scale; however, this research provides valuable information regarding reproduction in this basal reptile.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Endangered Species*
  • Female
  • Genitalia, Female / anatomy & histology
  • Genitalia, Male / anatomy & histology*
  • Genitalia, Male / physiology
  • Insemination, Artificial / veterinary*
  • Male
  • Microscopy, Electron, Scanning
  • Reptiles / anatomy & histology*
  • Reptiles / physiology
  • Semen Analysis / methods
  • Spermatozoa / physiology
  • Spermatozoa / ultrastructure*

Associated data

  • figshare/10.6084/m9.figshare.13377350

Grants and funding

SKL and SNK are supported by Victoria University of Wellington. NJN and DKO received a Faculty Strategic Research Grant from Victoria University of Wellington for this research (#208720). HRT was supported by a Marsden Fast Start Grant (#UOO1614) and the University of Otago. JAM is supported by Grand Valley State University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.