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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">A lot of amphibian larvae are housed in 10% buffered formalin long-term because it helps prevent the softer body parts from shrinking in ethanol. I have, however,
found it difficult to maintain the pH properly and even the best of formalin solutions can result in some specimen clearing long-term.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I do not keep reptile eggs in formalin. I fix them in formalin and then transfer them to ethanol. Long-term exposure to formalin can damage the eggshell and
cause issues with histology. I treat reptile eggs as I would a whole reptile specimen and transfer them to 70% ethanol for long-term storage.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Amphibian eggs and egg masses stay in 10% buffered formalin because they do shrink in ethanol to the point that they are essentially useless.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">But, as for amphibian larvae, we’ve started transferring them to 70% ethanol for long-term storage. This also makes them easier to work with from a health
and safety perspective, especially with a lot of student workers. Honestly the vast majority of our amphibian larvae were field preserved in 70% ethanol to begin with and never had formalin used. The added bonus is that DNA can be more easily extracted from
them, but the down-side is that the more delicate features are difficult to discern.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I think that no matter what you do, there will be a cost/benefit. Understand your institutional priorities and weigh those against the rarity of the specimen.
This also might be a good reason to photograph examples of each taxon/developmental stage PRIOR to changing storage fluid. Even if you only change to new formalin, you should document. There’s a chance that your formalin isn’t buffered the same way as what
was used in the past. That difference can cause some issues with the specimens. So, really, whatever you do there is a risk. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Good luck<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Greg<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">--------------------------------------</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Gregory J. Watkins-Colwell<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Collection Manager, Herpetology and Ichthyology</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Division of Vertebrate Zoology</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Yale Peabody Museum of Natural History</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">170 Whitney Avenue, Box 208118</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">New Haven, CT 06520</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">203/432-3791 or fax: 203/432-9277</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">-----------------------------------</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> nhcoll-l-bounces@mailman.yale.edu [mailto:nhcoll-l-bounces@mailman.yale.edu]
<b>On Behalf Of </b>Carola Haas<br>
<b>Sent:</b> Thursday, June 19, 2014 3:44 PM<br>
<b>To:</b> nhcoll-l@mailman.yale.edu<br>
<b>Subject:</b> [Nhcoll-l] long-term storage of amphibian larvae in formalin<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I received such great help for my previous request, and hope folks won't mind my sending another one so soon. (I'm just a field biologist who has been tasked with a cleanout and reorganization of our collection.)<o:p></o:p></p>
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<p class="MsoNormal">We have a number of larval amphibians (tadpoles and salamander larvae) preserved in 10% buffered formalin. Most of our fish, amphibian, and reptile specimens were fixed in formalin but then transferred over to ethanol for long-term storage.
I have read that formalin is more appropriate for long-term storage of reptile eggs and larval amphibians, but I wanted to check and make sure that is still the current practice?<o:p></o:p></p>
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<p class="MsoNormal">I would like to improve the safety of our collections by switching to ethanol if that is acceptable, but obviously not if it will degrade the specimens.<o:p></o:p></p>
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<p class="MsoNormal">Thank you!<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:13.5pt"><span style="font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black">Carola A. Haas<br>
Professor, Wildlife Ecology<br>
Dept. of Fish & Wildlife Conservation<br>
112 Cheatham Hall<br>
MC 0321 Virginia Tech<br>
Blacksburg, VA 24061<br>
<a href="mailto:cahaas@vt.edu">cahaas@vt.edu</a><br>
540-231-9269<br>
<a href="http://www.fishwild.vt.edu/faculty/haas.htm">http://www.fishwild.vt.edu/faculty/haas.htm</a><br>
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