<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title>UTas ePrints - Embryonic Gonadal and Sexual Organ Development in a Small Viviparous Skink, Niveoscincus ocellatus</title> <script type="text/javascript" src="http://eprints.utas.edu.au/javascript/auto.js"><!-- padder --></script> <style type="text/css" media="screen">@import url(http://eprints.utas.edu.au/style/auto.css);</style> <style type="text/css" media="print">@import url(http://eprints.utas.edu.au/style/print.css);</style> <link rel="icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="shortcut icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="Top" href="http://eprints.utas.edu.au/" /> <link rel="Search" href="http://eprints.utas.edu.au/cgi/search" /> <meta content="Neaves, Linda" name="eprints.creators_name" /> <meta content="Wapstra, Erik" name="eprints.creators_name" /> <meta content="Birch, Debra" name="eprints.creators_name" /> <meta content="Girling, Jane E." name="eprints.creators_name" /> <meta content="Joss, Jean M.P." name="eprints.creators_name" /> <meta content="" name="eprints.creators_id" /> <meta content="erik.wapstra@utas.edu.au" name="eprints.creators_id" /> <meta content="" name="eprints.creators_id" /> <meta content="" name="eprints.creators_id" /> <meta content="" name="eprints.creators_id" /> <meta content="article" name="eprints.type" /> <meta content="2007-10-14 22:07:33" name="eprints.datestamp" /> <meta content="2008-01-08 15:30:00" name="eprints.lastmod" /> <meta content="show" name="eprints.metadata_visibility" /> <meta content="Embryonic Gonadal and Sexual Organ Development in a Small Viviparous Skink, Niveoscincus ocellatus" name="eprints.title" /> <meta content="pub" name="eprints.ispublished" /> <meta content="270604" name="eprints.subjects" /> <meta content="restricted" name="eprints.full_text_status" /> <meta content="see individual journal copyright transfer agreements" name="eprints.note" /> <meta content="The majority of research into the timing of gonad differentiation (and sex determination) in reptiles has focused on oviparous species. This is largely because: (1) most reptiles are oviparous; (2) it is easier to manipulate embryonic developmental conditions (e.g., temperature) of eggs than oviductal embryos and (3) modes of sex determination in oviparous taxa were thought to be more diverse since viviparity and environmental sex determination (ESD)/temperaturedependent sex determination (TSD) were considered incompatible. However, recent evidence suggests the two may well be compatible biological attributes, opening potential new lines of enquiry into the evolution and maintenance of sex determination. Unfortunately, the baseline information on embryonic development in viviparous species is lacking and information on gonad differentiation and sexual organ development is almost non-existent. Here we present an embryonic morphological development table (10 stages), the sequence of gonad differentiation and sexual organ development for the viviparous spotted snow skink (Niveoscincus ocellatus). Gonad differentiation in this species is similar to other reptilian species. Initially, the gonads are indifferent and both male and female accessory ducts are present. During stage 2, in the middle third of development, differentiation begins as the inner medulla regresses and the cortex thickens signaling ovary development, while the opposite occurs in testis formation. At this point, the Mu¨llerian (female reproductive) duct regresses in males until it is lost (stage 6), while females retain both ducts until after birth. In the later stages of testis development, interstitial tissue forms in the medulla corresponding to maximum development of the hemipenes in males and the corresponding regression in the females. " name="eprints.abstract" /> <meta content="2006" name="eprints.date" /> <meta content="published" name="eprints.date_type" /> <meta content="Journal of Experimental Zoology" name="eprints.publication" /> <meta content="305A" name="eprints.volume" /> <meta content="74-82" name="eprints.pagerange" /> <meta content="10.1002/jez.a.249." name="eprints.id_number" /> <meta content="TRUE" name="eprints.refereed" /> <meta content="1548-8969" name="eprints.issn" /> <meta content="http://dx.doi.org/10.1002/jez.a.249" name="eprints.official_url" /> <meta content="Austin HB. 1988. Differentiation and development of the reproductive system in the iguanid lizard, Sceloporus undulatus. Gen Comp Endocrinol 72:351–363. Blackburn DG. 2000. Reptilian viviparity: past research, future directions, and appropriate models. Comp Biochem Physiol A 127:391–409. Bull JJ. 1980. Sex determination in reptiles. Quart Rev Biol 55:3–21. Cogger HG. 2000. Reptiles and amphibians of Australia, 6th edition. Sydney: Reed New Holland Publishers. Dufaure J, Hubert J. 1961. Table de developpement du lezard vivipare: Lacerta (Zootoca) vivipara, Jacquin. Arch Anat Microsc Morphol Exp 50:309–327. Fox H. 1977. The urinogenital system of reptiles. In: Gans C, Huey RB, editors. Biology of reptiles, Vol. 6. New York: Liss. p 1–122. Ganesh S, Choudhary B, Raman R. 1999. Temporal differences between testis and ovary determinations with possible involvement of testosterone and aromatase in gonadal differentiation in TSD lacking lizard, Calotes versicolor. J Exp Zool 283:600–607. Greenbaum E, Carr JL. 2001. Sexual differentiation in the spiny softshell turtle (Apalone spinifera), a species with genetic sex determination. J Exp Zool 290:190–200. Hewavisenthi S, Parmenter CJ. 2002. Thermosensitive period for sexual differentiation of the gonads of the flatback turtle (Natator depressus Garman). Aust J Zool 50:521–527. Janzen FJ, Paukstis GL. 1991. Environmental sex determination in reptiles: ecology, evolution, and experimental design. Quart Rev Biol 66:149–175. Jones SM, Wapstra E, Swain R. 1997. Asynchronous male and female gonadal cycles and plasma steriod concentrations in a viviparous lizard, Niveoscincus ocellatus (Scincidae), from Tasmania. Gen Comp Endocrinol 108:271–281. Melville J, Swain R. 2000a. Evolutionary relationships between morphology, performance and habitat openness in the lizard genus Niveoscincus (Scincidae: Lygosiminae). Biol J Linn Soc 70:667–683. Melville J, Swain R. 2000b. Mitochondrial DNA-sequence based phylogeny and biogeography of the snow skinks (Squamata: Scincidae: Niveoscincus) of Tasmania. Herpetologica 55:196–208. Merchant-Larios H, Ruiz-Ramirez S, Moreno-Mendoza N, Marmolejo-Valencia A. 1997. Correlation among themosensitive period, estradiol response, and gonad differentiation in the sea turtle Lepidochelys olivacea. Gen Comp Endocrinol 107:373–385. Morrish BC, Sinclair AH. 2002. Vertebrate sex determination: many means to an end. Reproduction 124:447–457. Olsson M, Shine R. 2001. Facultative sex allocation in snow skink lizards (Niveoscincus microlepidotus). J Evol Biol 14: 120–128. Pieau C. 1996. Temperature variation and sex determination in reptiles. Bioessays 18:19–26. Pieau C, Dorizzi M, Richard-Mercier N. 1999. Temperaturedependent sex determination and gonadal differentiation in reptiles. Cell Mol Life Sci 55:887–900. Raynaud A, Pieau C. 1985. Embryonic development of the genital system. In: Gans C, Billet F, editors. Biology of reptiles, Vol. 15. New York: Liss. p 149–301. Robert KA, Thompson MB. 2001. Viviparous lizard selects sex of embryos. Nature 412:698–699. Scherer G. 1999. Introduction: vertebrate sex determination and gonadal differentiation. Cell Mol Life Sci 55:821–823. Shine R. 1995. A new hypothesis for the evolution of viviparity in reptiles. Am Nat 145:809–823. Shine R. 1999. Why is sex determined by nest temperature in many reptiles? Trends Ecol Evol 14:186–189. Shine R, Harlow PS. 1996. Maternal manipulation of offspring phenotypes via nest-site selection in an oviparous lizard. Ecology 77:1808–1817. Shine R, Elphick MJ, Harlow PS. 1995. Sisters like it hot (advantages of temperature-determined sex). Nature 378: 451–452. Shine R, Elphick M, Donnellan S. 2002. Co-occurrence of multiple, supposedly incompatible modes of sex determination in a lizard population. Ecol Lett 5:486–489. Smith CA, Joss JMP. 1993. Gonadal sex differentiation in Alligator mississippiensis, a species with temperaturedependent sex determination. Cell Tissue Res 273:149–162. Thompson MB, Stewart JR, Speake BK, Hoise MJ, Murphy CR. 2002. Evolution of viviparity: what can Australian lizards tell us? Comp Biochem Physiol B 131:631–643. Uller, T. 2003. Viviparity as a constraint on sex-ratio evolution. Evolution 57:927–931. Wapstra E. 2000. Maternal basking opportunity affects juvenile phenotype in a viviparous lizard. Funct Ecol 14: 345–352. Wapstra E, O’Reilly JM. 2001. Potential ‘costs of reproduction’ in a skink: inter- and intra-populational variation. Austr Ecol 26:179–186. Wapstra E, Swain R. 2001a. Geographic and annual variation in life history traits in a small Australian skink. J Herpetol 35:194–203. Wapstra E, Swain R. 2001b. Reproductive correlates of abdominal fat body mass in a small skink with an asynchronous reproductive cycle. J Herpetol 35:403–409. Wapstra E, Swain R, Jones SM, O’Reilly J. 1999. Geographic and annual variation in reproductive cycles in the Tasmanian spotted snow skink, Niveoscincus ocellatus (Squamata: Scincidae). Aust J Zool 47:539–550. Wapstra E, Swain R, O’Reilly JM. 2001. Geographic variation in age and size at maturity in a small Australian viviparous skink. Copeia 2001:646–655. Wapstra E, Olsson M, Shine R, Edwards A, Swain R. 2003. Selection of offspring sex by a viviparous lizard: evidence for an adaptive explanation. Third International Symposium on Vertebrate Sex Determination, Kona, Hawaii, March 24–28. Wapstra E, Olsson M, Shine R, Edwards A, Swain R. 2004. Maternal basking behaviour determines offspring sex in a viviparous reptile. Proc R Soc, Lond B (Biol Lett) 271: S230–S232. Wibbels T, Bull JJ, Crews D. 1991. Chronology and morphology of temperature-dependent sex determination. J Exp Zool 260:371–381. Wibbels T, Wilson C, Crews D. 1999. Mu¨llerian duct development and regression in a turtle with temperature-dependent sex determination. J Herpetol 33:149–152. " name="eprints.referencetext" /> <meta content="Neaves, Linda and Wapstra, Erik and Birch, Debra and Girling, Jane E. and Joss, Jean M.P. (2006) Embryonic Gonadal and Sexual Organ Development in a Small Viviparous Skink, Niveoscincus ocellatus. Journal of Experimental Zoology, 305A . pp. 74-82. ISSN 1548-8969" name="eprints.citation" /> <meta content="http://eprints.utas.edu.au/2190/1/Embryonic_Gonadal.pdf" name="eprints.document_url" /> <link rel="schema.DC" href="http://purl.org/DC/elements/1.0/" /> <meta content="Embryonic Gonadal and Sexual Organ Development in a Small Viviparous Skink, Niveoscincus ocellatus" name="DC.title" /> <meta content="Neaves, Linda" name="DC.creator" /> <meta content="Wapstra, Erik" name="DC.creator" /> <meta content="Birch, Debra" name="DC.creator" /> <meta content="Girling, Jane E." name="DC.creator" /> <meta content="Joss, Jean M.P." name="DC.creator" /> <meta content="270604 Comparative Physiology" name="DC.subject" /> <meta content="The majority of research into the timing of gonad differentiation (and sex determination) in reptiles has focused on oviparous species. This is largely because: (1) most reptiles are oviparous; (2) it is easier to manipulate embryonic developmental conditions (e.g., temperature) of eggs than oviductal embryos and (3) modes of sex determination in oviparous taxa were thought to be more diverse since viviparity and environmental sex determination (ESD)/temperaturedependent sex determination (TSD) were considered incompatible. However, recent evidence suggests the two may well be compatible biological attributes, opening potential new lines of enquiry into the evolution and maintenance of sex determination. Unfortunately, the baseline information on embryonic development in viviparous species is lacking and information on gonad differentiation and sexual organ development is almost non-existent. Here we present an embryonic morphological development table (10 stages), the sequence of gonad differentiation and sexual organ development for the viviparous spotted snow skink (Niveoscincus ocellatus). Gonad differentiation in this species is similar to other reptilian species. Initially, the gonads are indifferent and both male and female accessory ducts are present. During stage 2, in the middle third of development, differentiation begins as the inner medulla regresses and the cortex thickens signaling ovary development, while the opposite occurs in testis formation. At this point, the Mu¨llerian (female reproductive) duct regresses in males until it is lost (stage 6), while females retain both ducts until after birth. In the later stages of testis development, interstitial tissue forms in the medulla corresponding to maximum development of the hemipenes in males and the corresponding regression in the females. 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border: solid 1px #ccc; padding: 3px"><tr> <td align="left"><a href="http://eprints.utas.edu.au/cgi/users/home">Login</a> | <a href="http://eprints.utas.edu.au/cgi/register">Create Account</a></td> <td align="right" style="white-space: nowrap"> <form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/search" style="display:inline"> <input class="ep_tm_searchbarbox" size="20" type="text" name="q" /> <input class="ep_tm_searchbarbutton" value="Search" type="submit" name="_action_search" /> <input type="hidden" name="_order" value="bytitle" /> <input type="hidden" name="basic_srchtype" value="ALL" /> <input type="hidden" name="_satisfyall" value="ALL" /> </form> </td> </tr></table></td></tr> <tr> <td class="toplinks"><!-- InstanceBeginEditable name="content" --> <div align="center"> <table width="720" class="ep_tm_main"><tr><td align="left"> <h1 class="ep_tm_pagetitle">Embryonic Gonadal and Sexual Organ Development in a Small Viviparous Skink, Niveoscincus ocellatus</h1> <p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Neaves, Linda</span> and <span class="person_name">Wapstra, Erik</span> and <span class="person_name">Birch, Debra</span> and <span class="person_name">Girling, Jane E.</span> and <span class="person_name">Joss, Jean M.P.</span> (2006) <xhtml:em>Embryonic Gonadal and Sexual Organ Development in a Small Viviparous Skink, Niveoscincus ocellatus.</xhtml:em> Journal of Experimental Zoology, 305A . pp. 74-82. ISSN 1548-8969</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/2190/1/Embryonic_Gonadal.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/2190/1/Embryonic_Gonadal.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />439Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input accept-charset="utf-8" value="2755" name="docid" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1002/jez.a.249">http://dx.doi.org/10.1002/jez.a.249</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">The majority of research into the timing of gonad differentiation (and sex determination) in reptiles has focused on oviparous species. This is largely because: (1) most reptiles are oviparous; (2) it is easier to manipulate embryonic developmental conditions (e.g., temperature) of eggs than oviductal embryos and (3) modes of sex determination in oviparous taxa were thought to be more diverse since viviparity and environmental sex determination (ESD)/temperaturedependent sex determination (TSD) were considered incompatible. However, recent evidence suggests the two may well be compatible biological attributes, opening potential new lines of enquiry into the evolution and maintenance of sex determination. Unfortunately, the baseline information on embryonic development in viviparous species is lacking and information on gonad differentiation and sexual organ development is almost non-existent. Here we present an embryonic morphological development table (10 stages), the sequence of gonad differentiation and sexual organ development for the viviparous spotted snow skink (Niveoscincus ocellatus). Gonad differentiation in this species is similar to other reptilian species. Initially, the gonads are indifferent and both male and female accessory ducts are present. During stage 2, in the middle third of development, differentiation begins as the inner medulla regresses and the cortex thickens signaling ovary development, while the opposite occurs in testis formation. At this point, the Mu¨llerian (female reproductive) duct regresses in males until it is lost (stage 6), while females retain both ducts until after birth. In the later stages of testis development, interstitial tissue forms in the medulla corresponding to maximum development of the hemipenes in males and the corresponding regression in the females. </p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">see individual journal copyright transfer agreements</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/270604.html">270000 Biological Sciences > 270600 Physiology > 270604 Comparative Physiology</a></td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2190</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Dr Erik Wapstra</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">15 Oct 2007 09:07</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">09 Jan 2008 02:30</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2190;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=2190">item control page</a></p> </td></tr></table> </div> <!-- InstanceEndEditable --></td> </tr> <tr> <td><!-- #BeginLibraryItem "/Library/footer_eprints.lbi" --> <table width="795" border="0" align="left" cellpadding="0" class="footer"> <tr valign="top"> <td colspan="2"><div align="center"><a href="http://www.utas.edu.au">UTAS home</a> | <a href="http://www.utas.edu.au/library/">Library home</a> | <a href="/">ePrints home</a> | <a href="/contact.html">contact</a> | <a href="/information.html">about</a> | <a href="/view/">browse</a> | <a href="/perl/search/simple">search</a> | <a href="/perl/register">register</a> | <a href="/perl/users/home">user area</a> | <a href="/help/">help</a></div><br /></td> </tr> <tr><td colspan="2"><p><img src="/images/eprints/footerline.gif" width="100%" height="4" /></p></td></tr> <tr valign="top"> <td width="68%" class="footer">Authorised by the University Librarian<br /> © University of Tasmania ABN 30 764 374 782<br /> <a href="http://www.utas.edu.au/cricos/">CRICOS Provider Code 00586B</a> | <a href="http://www.utas.edu.au/copyright/copyright_disclaimers.html">Copyright & Disclaimers</a> | <a href="http://www.utas.edu.au/accessibility/index.html">Accessibility</a> | <a href="http://eprints.utas.edu.au/feedback/">Site Feedback</a> </td> <td width="32%"><div align="right"> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><img src="http://www.utas.edu.au/shared/logos/unioftasstrip.gif" alt="University of Tasmania Home Page" width="260" height="16" border="0" align="right" /></a></p> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><br /> </a></p> </div></td> </tr> <tr valign="top"> <td><p> </p></td> <td><div align="right"><span class="NoPrint"><a href="http://www.eprints.org/software/"><img src="/images/eprintslogo.gif" alt="ePrints logo" width="77" height="29" border="0" align="bottom" /></a></span></div></td> </tr> </table> <!-- #EndLibraryItem --> <div align="center"></div></td> </tr> </table> </body> </html>