Book Review by M.H. Godfrey

Marine Turtle Newsletter 99:23-24, © 2003

BOOK REVIEW: The Anatomy of Sea Turtles

Matthew H. Godfrey

North Carolina Wildlife Resources Commission, 307 Live Oak Street, Beaufort, NC 28516 USA, and Mark Dodd, Georgia DNR, One Conservation Way, Brunswick, GA 31520-8687

Title: The Anatomy of Sea Turtles

Author: Jeanette Wyneken

Publisher: NMFS, U.S. Department of Commerce

NOAA Technical Memorandum NMFS-SEFSC-470

Pages: 172 + vii

Price: FREE

To order: Send written request to:National Marine Fisheries Center, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, Florida 33149 USA, PDF version freely available at:
http://courses.science.fau.edu/~jwyneken/sta/

This manual represents a major step forward from the previously available anatomical guide of Rainey (1981) that was limited in scope. This newer guide provides great detail on different anatomical subjects, including skeletal, circulatory, pulmonary, urogential, and nervous systems. It is designed for a wide audience, from experienced anatomists and veterinarians to students and amateur herpetologists. It is simply and clearly written, increasing its value to international readers whose first language may not be English. Structures of interest are typeset in bold throughout, to aid those who are searching via the index for a particular anatomical formation/structure. The manual is full of clear photos, nearly each of which is paired with a deftly drawn black and white illustration with labels for the appropriate/corresponding anatomical structures. It is packaged together with a multimedia CD, which contains the manual in PDF format, and several digital movies that further explain the different systems and anatomical components described in the text.

The guide begins with an excellent section on species identification, including differences among skulls, which can be challenging to students. It is somewhat inconvenient, however, not to have the species-specific characteristics of the entoplastron bone included in the species description section (Fig. 98, Pg. 51). There is also an exceptionally good section on standard measurements of sea turtles (pages 28-32), with real photographic examples, which complements and extends Bolten's (1999) chapter on turtle measurement found in the recent MTSG manual Research and Management Techniques for the Conservation of Sea Turtles. The rest of the guide is divided into general sections on different anatomical systems, and comparisons across species are highlighted. For example, the circulatory anatomy is well described, with photos of latex-injected carcasses that highlight the different arterial branches to specific anatomical systems (Figures 137a, b). The section on the brain and skull is particularly illuminating, and you will learn to distinguish quickly between the brain and salt glands (Figures 81 and 187). This guide also goes a long way in explaining some of the more esoteric anatomical structures associated with sea turtles, including the mysterious Rathke's glands (pages 120-123). Rathke's glands exist only in Lepidochelys, Eretmochelys, and Chelonia, and their function remains unknown. The tiny pineal gland, which sits atop the brain and is involved in transmitting information about changes in photoperiod for the synchronization of biological rhythms, is clearly shown in 5 different species (Figures 193-202). For those interested in collecting blood samples from sea turtles, there is an extended section on the structure and position of the external jugular vein (or dorsal cervical sinus), which is commonly used to collect blood (pages 87-94).

Only a few anatomical details are described less well. For instance, the pancreas is nearly invisible in Figure 136a, and is not highlighted in some of the other figures/photographs where it is more clearly visible (pages 119-120). Indeed, the latter section clearly lacks paired line drawings with labels, and the figure numbers are out of sequence and likely incorrect, adding to the confusion. The author of the manual is preparing a list of errors with corresponding corrections that should soon be available at the website noted above. Another structure lacking clear description and illustrations is the gonad and in particular the differences between males and females (pages 154-162). Determining the sex of immature individuals is arguably the most difficult aspect of necropsies, and information on sex is extremely useful in analyzing stranding data; hence, one might have expected a bit more detail for discerning between males and females. A one-page guide similar to the one presented for species identification (page 4) would have been helpful. Both the pancreas and sex-specific differences of the gonads are better explained and visualized in the video on the accompanying multimedia CD.

The multimedia CD consists of the PDF version of the guide and 4 complementary videos. The PDF is identical to the printed guide except that the photos are in color, which enhances the presentation and differentiation of the different structures. For instance, the different vessels of the circulatory system are more easily distinguished in the color photographs of the PDF version. The 4 complementary videos each run between 5 and 9 minutes in length, and they focus on species identification, measurement, gross dissection of the carcass, and the identification of major anatomical landmarks, including the gonads. Not only are the videos useful for the novice preparing to dissect a carcass, but also for those with previous experience who may be unsure about some of the different internal structures. The accompanying narration is slow and clear, making it easier for non-native English speakers to follow.

So, armed with this guide, its accompanying CD, and a dissection kit, you are on your way to determining what caused the death of any stranded sea turtle you may find, right? Wrong. This guide was not designed for necropsies and this is clearly stated in the first paragraph of the preface (page v). The primary objective of this manual is to provide an up-to-date guide to the normal anatomy of all species of sea turtles. The Anatomy of Sea Turtles is an essential component when preparing to do necropsies. After all, you need to know what a normal turtle looks like before you try to discern the cause of death of a stranded turtle. If you take this book with you for your next stranded turtle, be prepared to find major differences between what you see on the beach and in the book. The book gives examples of necropsies of fresh-dead animals, whereas in the field you usually will perform a necropsy on a mildly or severely decomposing animal. The guide occasionally notes what the structure may look like in a decomposing carcass (e.g. the thyroid gland, page 116), but a thorough guide to necropsies would require a separate major undertaking. At the current time, the best way to prepare for doing necropsies is to practice with someone who is already well versed in opening and investigating dead stranded turtles. It is a good idea to try to develop a collaborative relationship with a local veterinarian, who can help with necropsies and determine what may or may not be normal. Also, you can take a look at the following website: http://www.vetmed.ufl.edu/sacs/wildlife/seaturtletechniques/index.htm, although there are no visual aides to guide you through some of the techniques suggested.

To conclude, the Anatomy of Sea Turtles is an excellent resource for those wishing to learn more about structure and function of the internal anatomy of sea turtles, and although it should not be used as a guide for necropsies, it is an essential tool when preparing to investigate sea turtle carcasses.

Matthew H. Godfrey, North Carolina Wildlife Resources Commission, 307 Live Oak Street, Beaufort, NC 28516 USA, and Mark Dodd, Georgia DNR, One Conservation Way, Brunswick, GA 31520-8687 USA