The Anatomy of Sea Turtles

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1 Close this window to return to the previous pge or go to The Antomy of Se Turtles Jenette Wyneken, Ph.D. Illustrted y Dwn Witherington Close this window to return to the previous pge or go to

2 Close this window to return to previous pge or go to Species Identifiction from Skulls The following descriptions re sed upon ony chrcteristics lone nd do not include other dignostic fetures of the scles or the form of the rhmpothec (kertinceous ek, see Rhmphothec Structure, pp ). Cheloni myds (Figs ). The skull is rounded with short snout nd shllow prietl notches (Fig. 31). The upper jw is descried y smooth U-shped outline; the plte etween the mrgins of the upper jw nd the internl nres (the lveolr surfce) hs pir of ridges tht run prllel to the outer edge of the jw (Fig. 32). The lower jw, hs ridge running prllel to the inner surfce (Fig. 33) nd midline cusp. Figs. 31 nd 31. Cheloni myds, lterl view. The Antomy of Se Turtles 13 Close this window to return to previous pge or go to

3 Close this window to return to previous pge or go to Figs. 32 nd 32. Cheloni myds, dorsl nd ventrl skull. Note ridges on plte t rrows. 14 The Antomy of Se Turtles Close this window to return to previous pge or go to

4 Close this window to return to previous pge or go to U-shped plte Figs. 33 nd 33. Cheloni myds, ventrl skull nd lower jw. Midline cusp of lower jw t rrow. The Antomy of Se Turtles 15 Close this window to return to previous pge or go to

5 Close this window to return to previous pge or go to Crett crett (Figs. 34 nd 35). The hed of the loggerhed is reltively lrge, wide posteriorly, nd the snout tpers nterior to the orits. The prietl notches (wide U-shpe emrgintions formed y the posterior orders of the squmosl, prietl nd suproccipitl ones) re lrge (Fig. 34). The jws re roust nd shped like wide V. Loggerheds hve reltively long secondry plte. (The secondry plte is the shelf of one tht seprtes or prtilly seprtes food nd ir pssges.) The plte lcks lveolr ridges nd the two mxillry ones contct one nother posterior to the premxillry ones (Fig. 35). Figs. 34 nd 34. Crett crett, dorsl skull nd lower jw. Prietl notches re t rrows. prietl notch 16 The Antomy of Se Turtles Close this window to return to previous pge or go to

6 Close this window to return to previous pge or go to secondry plte Figs. 35 nd 35. Crett crett, ventrl skull nd lower jw. Note tht the two mxillry ones touch t the middle of the plte. The Antomy of Se Turtles 17 Close this window to return to previous pge or go to

7 Close this window to return to previous pge or go to Lepidochelys kempii (Fig. 36). The skull is similr in overll shpe to tht of the loggerhed ut cn e distinguished from the loggerhed y the fetures of the plte. The Kemp s ridley skull is roughly tringulr in shpe. The prietl notches re well developed (Fig. 36). The snout tpers nterior to the orits. The jws re shped like wide curved V nd there is reltively long secondry plte. The plte hs longitudinl lveolr ridges nd the two mxillry ones re seprted y the vomer which extends nteriorly to rticulte with the premxillry ones (Figs. 27 nd 36). The orits re reltively smll when compred with other species nd ech hs ridge of one long its dorsl mrgin tht extends lterlly from the nterior portion of the postoritl one. Figs. 36 nd 36. Lepidochelys kempii, dorsl nd ventrl skull. lveolr ridges 18 The Antomy of Se Turtles Close this window to return to previous pge or go to

8 Close this window to return to previous pge or go to Lepidochelys olivce (Figs ). The olive ridley skull is similr in shpe to skulls of the loggerhed nd Kemp s ridley. It is roughly tringulr in shpe, wide posteriorly, nd hs deep prietl notches. The jws re shped like wide V. The plte lcks lveolr ridges. The two mxillry ones re seprted y the vomer which rticultes with the premxillry ones. The orits re lrger thn in L. kempii (Figs ) nd the pterygoid ones re rod t their nrrowest point when compred with other species. Figs. 37 nd 37. Lepidochelys olivce, dorsl skull pterygoid one pltine one pterygoid process Figs. 38 nd 38. Lepidochelys olivce, ventrl skull. The pterygoid one of the olive ridley is proportiontely wider nd the pterygoid processes re more pronounced thn in the Kemp s ridley. The Antomy of Se Turtles 19 Close this window to return to previous pge or go to

9 Close this window to return to previous pge or go to Figs. 39 nd 39. Lepidochelys olivce, lterl skull. When mesured cross its longest xis, the orits of L. olivce re proportiontely lrger thn those of L. kempii. 20 The Antomy of Se Turtles Figs. 40 nd 40. Lepidochelys kempii, lterl skull. Note the proportionlly smller orit nd slightly more hooked snout. Close this window to return to previous pge or go to

10 Close this window to return to previous pge or go to Eretmochelys imrict (Figs ). The hwksill skull is long nd nrrow in ll ut the youngest turtles (htchlings). The length is pproximtely equl to twice the width (mesured t the skull's widest prt; Fig. 42). Hwksill skulls hve deep prietl notches nd the snout tpers to point. The jws re V-shped nd nrrow (Fig. 41). The secondry plte is well developed nd the internl nres re situted in the nterior third of the mouth. The two mxillry ones re seprted y the vomer which extends nteriorly to rticulte with the premxillry ones (Fig. 42). Figs. 41 nd 41. Eretmochelys imrict, dorsl skull nd lower jw with rhmpothec. The jws re very nrrow nd V-shped. prietl notch is deep V - shpe The Antomy of Se Turtles 21 Close this window to return to previous pge or go to

11 Close this window to return to previous pge or go to W ~ 2X W=L L Figs. 42 nd 42. Eretmochelys imrict, ventrl skull nd lower jw. The skull is longer nd nrrower thn tht of ny other species. The secondry plte is long so tht the internl nres (rrow) re reltively fr ck. 22 The Antomy of Se Turtles Close this window to return to previous pge or go to

12 Close this window to return to previous pge or go to Dermochelys corice (Figs ). Letherck skulls re unlikely to e mistken for those of ny other species. The skull is wide nd rounded nteriorly with lrge orits; there re no prietl notches (Fig. 43). The ones rticulte loosely; there is little or no secondry plte (Fig. 44). The mrgins of the jws re shrp nd possess notches. There re pointed cusps on the nterior mxillry ones. The lower jw comes to dorslly directed point t the mndiulr symphysis (where the two hlves of the lower jw join). The lower jw hs crtilginous portion medil to the dentry. Figs. 43 nd 43. Dermochelys corice, dorsl skull nd lower jw. The ones fit together more loosely thn in other species. The letherck skull nd skeleton hs een descried s neotenic (hving emryonic chrcteristics) in form ecuse of the lck of ony fusions. The Antomy of Se Turtles 23 Close this window to return to previous pge or go to

13 Close this window to return to previous pge or go to Figs. 44 nd 44. Dermochelys corice, ventrl skull nd lower jw. Note the lck of secondry plte nd the loose rticultions of the ones. notch 24 The Antomy of Se Turtles Close this window to return to previous pge or go to

14 Close this window to return to previous pge or go to f e d c Fig. 45. Skulls of ll the species found in US wters. Clockwise from top right: Dermochelys corice (), Eretmochelys imrict (), Cheloni myds (c), Lepidochelys olivce (d), Lepidochelys kempii (e), Crett crett (f). The hwksill, green turtle nd Kemp's ridley skulls re from immture nimls, others re from dults. The Antomy of Se Turtles 25 Close this window to return to previous pge or go to