Reply to the Commentary of Charles J. Innis: “Testes Morphology in Cuora flavomarginata”

Hernandez-Divers et al. (2009) presented “an endoscopic method for identifying sex of hatchling Chinese box turtles…” (title of the paper) without any description or discussion of the visual appearance and morphology of the gonads they identified. The only results they provided regarding their endoscopic interpretation was: “In all 58 hatchlings, the gonads were located and identified as testes or ovaries (Figure 2). Four of the 58 hatchlings were identified as males, and 54 were identified as females.” The only additional hint regarding their interpretation of the morphology of the testis can be found in the legend of Figure 2: “b—Close-up view of the testis illustrating the smooth surface and surface vasculature.” (Hernandez-Divers et al. 2009:802).

As mentioned in the commentary of Dr Charles Innis I wrote a letter to the editor of the Journal of the American Veterinary Medical Association (JAVMA) and pointed out: “illustrations of the ‘testis’ in C. flavomarginata show radically different structures from those previously described and illustrated as juvenile turtle testes” and summed my letter up with: “I believe that the structure labeled ‘testis’ in illustrations from Hernandez-Divers et al. does not represent a testis or any other part of the genital tract” (Kuchling 2009:932). My arguments were solely based on the morphology of the testis as visible in Figure 2 of Hernandez-Divers et al. (2009)—the only hint they provided to their visual interpretation of a testis in hatchling Chinese box turtles—and largely similar to those in the respective discussion of Kuchling and Griffiths (2012). In their rebuttal of my letter to the editor Divers and Stahl (2009) neither discussed nor rebutted any of my morphological arguments nor did they consider and discuss their results in the context of the existing literature and the available knowledge on the morphology of juvenile chelonian testes. Since among other things Dr Innis states in his commentary: “in their rebuttal, Divers and colleagues provided a strong argument for the correct identity of the testes based on the organs' consistent bilateral presence in four turtles…”, information I cannot locate either in Divers and Stahl (2009) or in Hernandez-Divers et al. (2009), it appears Dr Innis had access to information from the authors which is not available to the general readership of JAVMA. Divers and Stahl (2009) limited their published rebuttal largely to discussions of procedural differences in endoscopic methods and photographic documentation and to differences in the quality of endoscopic equipment and training opportunities. In addition they listed specifically by first name, last name, and employer 3 veterinarians including Dr Innis who “have independently confirmed that our identification of the testis is accurate” (Divers and Stahl 2009:933). I agree with Dr Innis that this whole approach to a scientific discussion seems odd. I am sorry that my referencing of the names listed by Divers and Stahl (2009) in my later papers on the morphology of juvenile chelonian gonads (Kuchling et al. 2011; Kuchling and Griffiths 2012) apparently caused chagrin, but I am used to discussing my results in the light of the existing literature.

Given the limited images of the juvenile testis of C. flavomarginata and the lack of description and discussion of its morphology in Hernandez-Divers et al. (2009) and Divers and Stahl (2009) I agree with Dr Innis that, following general scientific convention, the best way to find out if the illustrated structure is a testis or not would be to obtain a group of juvenile C. flavomarginata and repeat the study. I have not yet had this opportunity, but since the publication of Kuchling and Griffiths (2012) I have endoscopically examined an adult male C. flavomarginata and I had the opportunity, during August 2012 in collaboration with Dr Paul Gibbons at the Behler Chelonian Center, to endoscopically sex several 1-yr-old Cuora trifasciata. I am happy to concede that my suggestion was wrong that the structure labelled “testis” in illustrations of Hernandez-Divers et al. (2009) does not represent a testis or any other part of the genital tract. The juvenile testis of C. trifasciata is also radically different in endoscopic appearance and morphology from the juvenile testis of the other turtle families mentioned by Kuchling and Griffiths (2012) and of that of other genera of the family Geoemydidae which I have examined. The testis of juvenile C. trifasciata has similarities with the testis of C. flavomarginata as illustrated in Fig. 2a, b of Hernandez-Divers et al. (2009:802) and, in particular, the theca testis does contain melanocytes (for an endoscopic image of the juvenile testis of C. trifasciata see http://news.turtleconservancy.org/2012/09/behler-chelonian-center-update-august-2012/). This suggests that probably the genus Cuora as a whole may be unique among chelonians regarding the morphology of the juvenile testis and its appearance during endoscopy.