Bulletin 34 - March 1988: Identification for the World's Sea Turtles
Identification for the World's Sea Turtles
by J.N.B. Brown
The following notes are taken from "Sea Turtles" by Robert Bustard, published
by William Collins Sons & Co., Glasgow.
Although only three species have so far been identified in the Arabian Gulf and
Gulf of Oman at the latest update of 20.11.1987, that is not to state that other
species might not occur from time to time. The three positive recordings are the
Green, Leatherback and Loggerhead turtles. It is hoped that this key will be an
aid to identification and possibly lead towards the recordings of further species.
- I. A. Four costal scutes on either side of carapace (Fig. la, CI - C4) i nuchal
(N) separated from first costal (Cl) by first vertebra (VI).
- 1. One pair of elongated prefrontals (Fig.2 , pf); scutes of the shell do
- a. Scales on upper surfaces of distil half of front flippers large (Fig.3).
Areas of much smaller scales between the phalanges lacking. Postocular count usually
four. Shell colour usually light to dark brown with darker markings giving a mottled
- Green Turtle (Chelonia mydas)
- b. Distil half of front flippers with single rows of large scales extending
along phalanges. Many minute scales or wrinkled skin present on intervening areas
(Fig.3). Three postoculars. Shell greatly depressed, marginals (M) curve upward.
Shell colour olive-grey.
- Flatback (Chelonia depressa)
- 2. Two pairs of prefrontals (Fig.2,pf) i scales of the shell overlapping like
the tiles on a roof. Shell colour amber with streak-like markings of red-brown,
black and yellow.
Hawksbill (Eretmochelys imbricata)
- B. Five or more costal shields on either side of carapace (Fig.lb-c, CI-C5);
nuchal (N) in contact with first costal (Cl) (Fig.lb-c); two pairs of prefrontals
or a group of five or more shields and scales on the prefrontal region (Fig.2c).
- 1. Five (rarely six) costal shields on either side of carapace (Fig. 1b, C1
- a. Shell always considerably longer than wide. Inframarginal scutes lack pores.
Shell colour reddish brown to brown.
- Loggerhead (Caretta caretta)
- b. Carapace extremely broad in relation to length; may be even broader than
long. Inframarginals with a pore (minute opening) at hind border. Carapace grey-brown
to blackish or olive-green.
- Kemp's Ridley (Lepidochelys kempi)
- 2. Six to nine costal shields on either side of carapace (Fig.1c). Shell relatively
broad. Shell colour grey-green to dark brown.
- Olive Ridley (Lepidochelys olivaceas)
- II. Shell covered with a thick leathery skin and strongly tapering towards
the rear (Fig.1d). Forelimbs lack claws. Colour of upper parts blackish. Small
irregular white or pinkish spots often present.
- Leatherback (Dermochelys coriacea)
Olive Ridley (Pacific) - Lepidochelys olivacea
Leatherback (widely-distributed in warm seas, common in parts of Atlantic)
- Dermochelys coriacea
Green (widely-distributed)- Chelonia mydas
Hawksbill (tropical & sub-tropical seas) - Eretmochelys umbricata
Loggerhead (widely distributed in warm seas, common along Atlantic coast
of Central America Brazil and USA) - Caretta caretta
Kemp's Ridley (common in parts of the Atlantic) - Lepidochelys
Flatback - Chelonia depressa
'Green Turtle', ENHG Bulletin 5, July 1978.
'The Loggerhead Turtle', ENHG Bulletin 7, April 1979 & 21, November 1983.
'Recent Turtle Records', ENHG Bulletin 24, November 1984.