(( N0V17 1E55 
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Vol. 68, pp. 157-164 ^^^^^ ''^ -"^^.J^-^ October 31, 1955 
PROCEEDINGS 
OF THE 
BIOLOGICAL SOCIETY OF WASHINGTON 
THE DIAMONDBACK TERRAPINS {MALACLEMY8 
TERRAPIN) OF PENINSULAR FLORIDA 
By Albert Schwartz 
The Charleston Museum, Charleston, 8. C. 
As presently understood, three subspecies of diamondback 
terrapins (Malaclemys terrapin) inhabit the coastal waters of 
the Florida Peninsula and the Florida Keys. As mapped by 
Carr (1952: 164) the ranges of these three forms are: Mala- 
clemys t. macrospilota, Florida west coast ; Malaclemys t. cen- 
trata, Florida east coast, south to about Palm Beach County; 
Malaclemys t. rhizopkorarum, Florida Keys, integrading with 
M. t. centrata along the southeastern coast and with M. t. 
macrospilota in the region of Cape Sable. 
Eecent acquisition of fresh material from the Florida east coast and 
the coast of South Carolina indicates that the status of the diamond- 
back turtles from the former locality is not as Carr indicated. In 
addition to material in the collection of the Charleston Museum, I have 
examined specimens from various institutions, and wish to extend my 
thanks for the loan of turtles to the following curators of collections: 
Charles M. Bogert and Eichard G. Zweifel, American Museum of 
Natural History (AMNH) ; Arthur Loveridge, Museum of Comparative 
Zoology (MCZ) ; Archie F. Carr and Duke Wilder, University of Florida 
(UF) ; Norman E. Hartweg and William E. Duellman, Museum of 
Zoology, University of Michigan (UMMZ), and Doris M. Cochran, 
United States National Museum (USNM). Numerous persons have 
aided in the collection of specimens of Malaclemys, and I wish to thank 
L. Neil Bell, Julian E. Harrison III, Eaymond P. Porter, John A. 
Quinby, and Ephie C. Seabrook for their assistance. Shell measurements 
follow Carr (1952), and all measurements are in millimeters. 
Malaclemys t. rhisophorarum was described by Fowler (1906) as 
Malaclemmys littoralis rhisophorarum, from a single specimen taken at 
Boca Grande Key, Monroe County, Florida. Boca Grande lies between 
Key West and the Marquesas. Carr (1946) resurrected the name rhizo- 
phorarum, after many years of disuse, for the diamondback terrapins 
of the Florida Keys, on the basis of a new specimen from Card Sound, 
Dade County, Florida, and the examination of turtles from the lower 
portion of the Florida Peninsula. Malacelmys t. macrospilota was 
described by Hay in 1905, from material taken at Charlotte Harbor, 
Florida, and the Florida West Coast; this Gulf Coast subspecies is 
readily separable from the Atlantic Coast material by virtue of the clear 
and sharply differentiated centers of the carapace laminae. Malaclemys 
27— Proo. Biol. Soc. Wash., Vol. 68, 1955 (157) 
KTstlKi 
158 Proceedings of the Biological Society of Washington 
t. centrata was first described from Carolina by Latreille in 1801, and 
later the type locality was restricted to CTiarleston, South Caroliaa, by 
Hay (1905:6). 
Examination of specimens from the east coast of Florida demonstrates 
that this region is inhabited by turtles which cannot be assigned to any 
of the named subspecies of Malaclemys terrapin. The Florida east 
coast areas were in the past the home of the Tequesta Indians and it 
seems appropriate to name the new subspecies after these early Americans 
for whom, almost certainly, the diamondback terrapin was an item of 
diet. The new subspecies may be kuo\vn as 
Malaclemys terrapin tequesta, new sub species 
Holotype: UMMZ 10S482, an adult female from Miami Beach, Dade 
County, Florida, taken June, 1953, by Donald de Sylva. 
Paratypes: All from Florida, as follows: Volusia Co., New Smyrna, 
(USNM 37020) Daytona Beach (UF 4242); Brevard Co., % mi. E 
junction Florida AIA and Florida 520 (UF 6589, UF 6590), 1.3 mi. 
E Merritt Island (UMMZ 106149, UMMZ 106150), 2 mi. E Merritt 
Island (UMMZ 106148), 5 mi. E Merritt Island (UMMZ 106151), 5.2 
mi. E Merritt Island (UMMZ 106147), Eau Gallie (MCZ 20287); In- 
dian Biver Co., Sebastian (MCZ 48787). 
Diagnosis: A diamondback turtle without strikingly differentiated trans- 
eueent centers or a pattern of concentric circles on the carapace lami- 
nae, and without black edging on the seams of the ventral surface 
of the marginal laminae. Carapace slightly keeled, broad, flattened, 
and horn-colored, occasionally carapace laminae cleared to show rem- 
nants of juvenile pattern; plastron either immaculate or with various 
dark patterns, either seam following, radiating from the posterior 
corner of the plastral laminae, or consisting of rectangular black 
hollow figures on each plastral lamina. Ventral surface of marginal 
laminae at level of bridge usually without a continuation of the dorsal 
pattern or with this pattern very obscure and poorly defined, and with 
a black blotch at the posterodorsal corner of the ventral surface of 
the marginals at the level of the bridge. Head skin variously mottled 
or stippled with dark gray on light gray background, but never with 
dark spots fused into lines. Juveniles usually without concentric rings 
on carapace laminae and dorsal surface of marginals, rarely with no 
more than two concentric rings on each lamina; usually each carapace 
and marginal lamina stippled with gray; if present, one (usually) to 
five (rarely) dark spots in the center of each lamina. Dorsal tubercles 
bulbous and either light or dark, that on central lamina 4 most pro- 
nounced. Plastron either uniformly lightly stippled with gray, or with 
each plastral lamina containing a square or triangular hollow dark 
figure which follows the configuration of the lamina but does not 
touch the seams. 
Distribution: The east coast of the Florida Peninsula, from at least 
Volusia County south to Dade County. 
Description of holotype: An adult female with the following measure- 
ments: Carapace length, 178; length of plastron, 157; length of anterior 
lobe of plastron, 41.0; length of middle lobe of plastron, 53.1; length 
f:T^' 
Schwartz — The Diamondhack Terrapins 159 
of posterior lobe of plastron, 63.2; head width, 37.2; depth, 72; width 
of posterior lobe of plastron, 82.8; width of bridge, 48.5; greatest 
width of carapace (at marginal 7), 139. 
The carapace is generally dark or horn-colored, the central laminae 
uniformly so. Each lateral lamina is lighter centrally, and one to 
several heavy bro^^'n spots are visible through the lighter center. The 
marginals are lighter than the laterals and a bold, open-sided square 
figure is visible on the dorsal surface of each marginal. The plastron 
is yellow and the central seam is widely bordered with dark radiating 
lines. Each plastral lamina shows the remnants of the triangular or 
rectangular hollow figure noted above as occurring in juveniles, and 
these plastral figures are somewhat obscured by additional dark pigment. 
The ventral surfaces of the marginal laminae show a hollow, poorly 
defined C-shaped figure, the open side directed dorsally, and marginals 
4 to 9 on each side have a brown blotch on the posterodorsal corner. 
The head skin is light gray and boldly spotted with black. The nasal 
shield is heavily stippled with black, and a black border occurs along 
its posterior third. The neck and fore limbs are light gray, spotted 
with black, while the hind limbs and rump are almost uniformly gray. 
Variation: The eleven adult specimens of M. t. tequesta (ten females 
and one male) show little variation compared to the holotype. All 
are broad and flattened, when compared to M. t. centrata, and all have 
the horn-colored carapace of the type. None shows any indication of 
the concentric circles on the carapace laminae, persistently character- 
istic in M. t. centrata, and three females (UF 6589, UF 4242, UMMZ 
106151) have the centers of the carapace laminae somewhat lighter, 
so that the remnants of the juvenile pattern (incomplete or diffuse 
circle or large brown dots) are still visible. All except two (UF 6589, 
UF 4242) have the dark blotch on the ventral surface of the marginals 
at the level of the bridge. The head skin is gray and either lightly 
and uniformly stippled, or with dark spots; the nasal shield varies from 
pale gray and immaculte, to solid black. The dorsal keels are but 
slightly tuberculate; the single male (MCZ 48787) has the keel on 
central 4 more bulbous than those on the preceding two centrals, and 
likewise more bulbous than the keels of any of the females. 
The outline of the shell of M. t. tequesta is more nearly oval than 
that of the remaining Floridian subspecies, and the carapace laminae 
show conspicuous concentric grooves. 
Comparisons: Malaclemys t. tequesta requires comparison with the 
three Floridian subspecies of the genus. The new form can easily be 
distinguished from M. t. macrospilota since the latter has translucent 
yellowish areas in the centers of the carapace laminae. M. t. tequesta 
shows occasional lightening of the carapace lamina but it is never so 
pronounced as in M. t. macrospilota and the clear areas are not so 
abruptly differentiated in the new subspecies, the transition between the 
horn-colored peripheries and the clear centers being very gradual. 
M. t. tequesta is also a broader and flatter turtle than M. t. macrospilota, 
and has a more oval outline than the west coast subspecies. Juveniles 
of M. t. macrospilota differ from those of M. t. tequesta in that the 
carapace laminae of the former subspecies are usually heavily spotted 
with black and each lamina is heavily black bordered. Concentric 
160 Proceedings of the Biological Society of Washington 
rings are absent on the lateral and central laminae on juvenile M. t. 
macrospilota. If the heavy spotting is absent on the lateral laminae 
of M. t. maerospilota, there is usually a single prominent black spot 
in the center of each lateral lamina. The bulbous keels on the centrals 
of juvenile M. t. maerospilota are somewhat more pronounced than 
those of M. t. tequesta. 
From M. t. centrata, M. t. tequesta differs in the absence of dark 
greenish or gray concentric rings on the light gray or green carapace 
laminae, and the presence of a dark blotch on the ventral surface of the 
marginal laminae at the level of the bridge. In M. t. centrata, the 
pattern of the dorsal surface of each marginal lamina continues onto 
the ventral surface of the same lamina as a square or rectangular 
figure. In M. t. tequesta, such ventral continuation of the marginal 
lamina pattern is either completely absent or is but faintly indicated. 
The juveniles of these two subspecies are easily differentiated. Juvenile 
M. t. centrata have three or more concentric rings in each lateral lamina, 
and a complex figure consisting of a combination of stippling and lines 
and/or rings on each central. The continuation of the marginal pattern 
from the dorsal to the ventral surface of each marginal lamina, noted 
in adult M. t. centrata, is even more conspicuous in juveniles. In 
juvenile M. t, tequesta, there are never more than two concentric rings 
in each carapace lamina, and these are poorly defined and occur in 
only five of sixteen juveniles. The bulbous keels of the centrals are 
very pronounced in juvenile M. t. tequesta, while the keels of juvenile 
M, t. centrata are not bulbous but are rather a linear, almost parallel 
sided, series. Carr (1952:175) shows an excellent photograph of hatch- 
ling M. t, centrata from Beaufort, North Carolina, and a series of 
twelve hatchlings from South Carolina and Savannah, Georgia, agree 
well with his photograph. The expansion of the keels in hatchling 
M. t. tequesta is reminiscent of the same condition in juvenile M. t. 
macrospilota. 
There are four specimens of Malaclemys (other than the type of 
M. t. rhisophorarum from the Florida Keys available to me. One of 
these (USNM 37021, adult female, Key West) is typical of M. t. 
macrospilota. This individual was taken many years ago and, since it 
does not agree with the remaining three specimens from the Florida 
Keys, it is suspected that this individual was captured by commercial 
fishermen along the lower west coast of Florida and brought to Key 
West, where it was purchased and later deposited in the United States 
National Museum. The remaining three specimens (MCZ 1848, adult 
female, MCZ 1849, adult male, both from the Marquesas, Monroe 
County, Florida ; AMNH 4745, juvenile, from Plantes, Key Long, 
Monroe County, Florida) differ in detail from M. t. tequesta and 
M, t. macrospilota, and are considered to represent M. t. rhisophorarum. 
I am unable to locate 'Plantes, Key Long' on any map; however, 
there has been, near the present site of the town of Tavernier, a 
settlement of Planter on Key Largo, and I suspect that the juvenile is 
really from this locality rather than 'Plantes, Key Long', 
Compared with the figure of M. t. rhizophorarum (Fowler, 1906), 
the two adults from the Marquesas show the black edging on the ventral 
surface of the marginal laminae (which Fowler considered diagnostic 
Schwartz— The Diamondhack Terrapins 161 
of M. t. rhizophorarum) and the black pigmentation radiating from 
the plastral seams. This condition occurs in M. t. macrospilota, as 
demonstrated in three adult females (UMMZ 104023, 109544, 109545) 
from Cedar Key, Levy County, Florida. However, no other specimen 
shows the fusion of dark spots on the head, giving the head a boldly 
streaked appearance, as do the two adults from the Marquesas. The 
juvenile from Key Largo shows the same head pattern condition, and 
the carapace is also very distinctly marked. Each lateral lamina has 
a bold, broad, doughnut-shaped figure, hollow on laterals 1 to 3, and 
solid on lateral 4. Central 1 has a W-shaped black figure, the open 
end directed anteriorly. The precentral and marginals 1 to 7 have a 
solid black blotch on the dorsal surfaces, while marginals 8 to 11 have 
a bold, C-shaped figure, the open end directed toward the periphery 
of the shell. Centrals 2 to 4 have each a dark bulbous keel, crossed 
by by a black bar. The plastral laminae are boldly spotted, with one 
to four spots on each lamina. The lateral ends of the pectoral and 
abdominal laminae each have a large black spot, and the ventral sur- 
face of each marginal likewise is marked with a black spot. These 
markings on the juvenile from Key Largo differ radically from those 
of any other juvenile examined, and, if characteristic of the populations 
of Malaclemys from the Florida Keys, are sufficiently distinct to 
separate the key juveniles from those of the mainland. Detailed com- 
parison of this juvenile M. t. rhisophoraruvi with those of M. t. centrata, 
M. t. macrospilota, or M. t. macrospilota, or M. t. tequesta is un- 
necessary. Adult M. t. rhizopJiorarum can be distinguished from M. t. 
tequesta by the fused and bold head spots, the absence of a dark 
spot on the ventral surface of the marginal laminae, and the presence 
of black borders on the ventral surface of the marginals. From M. t. 
macrospilota, the key turtles may be distinguished by the head markings 
and by the absence of clear centers of the carapace laminae. Much 
additional fresh material is needed before adequate assessment of the 
differentiating characters of M. t. rhizophorarum can be made. For 
the present it seems preferable to regard the mangrove terrapin as a 
distinct subspecies. 
Inspection of Table 1 shows that female M. t. tequesta average 
larger in measurements of carapace length, anterior lobe length, pos- 
terior length, posterior lobe width, depth, and carapace width; the 
differences are not striking, however. The ratio of depth over length 
of posterior lobe of plastron will separate most female specimens of 
M. t. centrata from female M. t. tequesta; only two individuals (out of 
20) of the former subspecies have this ratio in excess of 1.07, while 
this ratio in M. t. tequesta ranges between 1.07 and 1.19. Likewise, 
only six specimens of M. t. centrata have the ratio of carapace width 
over posterior lobe length greater than 1.99, while this ratio in M. t. 
tequesta ranges between 1.99 and 2.26. The ratio of depth over 
posterior lobe length averages equally in female M. t. tequesta and 
female M. t. macrospilota, and the ratio of carapace width over posterior 
lobe length averages less in M. t. macrospilota than in M. t. tequesta, 
although the extremes are identical. 
Adequate series of males of the Floridian races of Malaclemys 
terrapin, as well as M. t. centrata, are not available for comparison. 
162 Proceedings of the Biological Society of Washington 
I have examined nine male M. t. macrospilota, three male M. t. centrata, 
and one male each of M. t. tequesta and M. t. rhizophorarum. On the 
basis of this limited material, the following observations can be made. 
Male M. t. macrospilota have the light centers of the carapace laminae 
typical of this race, but old individuals may have this character 
obscured. In young males the carapace keel is bulbous, especially on 
centrals 3 and 4, but older individuals have the bulbous terminations 
less prominent and worn. M. t. centrata males show the dark gray or 
green concentric circles on the carapace laminae and the keel of the 
carapace is not bulbous, but rather a series of rather sharp carinae 
occur on centrals 2 to 4, with the keel on central 4 most pronounced. 
The single male M. t. tequesta is almost uniformly horn-colored dorsally, 
with the lateral laminae only slightly translucent. The dorsal keel 
is bulbous (especially on centrals 3 and 4), but not so prominent as in 
male M. t. macrospilota. The ventral survace of the marginals at the 
bridge level have the customary brown blotch typical of the subspecies. 
The male M. t. rhizophorartim is quite dark (almost black) above, 
and the central keel of the carapace is bulbous on centrals 2 and 4, 
but less pronounced than in M. t. macrospilota and M. t. tequesta. 
The ventral surface of the marginals shows the typical black seams, 
and the head shows the fusion of blotches characteristic of this sub- 
species. Measurements and proportions are shown in Table 2. From 
these data it appears that M. t. macrospilota males average larger 
than those of the three southeastern subspecies, and that male M. t. 
centrata can be separated from male M. t. macrospilota on the basis 
of the ratio of carapace width over length of posterior lobe of plastron. 
The single male M. t. rhizophorarum has a higher ratio of carapace 
width over length of posterior lobe of plastron than any other male 
examined, and additional specim.ens from the Florida Keys may indicate 
that this ratio will separate key specimens from the remaining Floridian 
subspecies. 
The areas of intergradation between M. t. tequesta and M. t. rhizo- 
phorarum to the south, and between the former subspecies and M. i. 
centrata to the north are unknown. Intergrades between M. t. tequesta 
and M. t. rhizophorarum might be expected on the southern coast of 
Florida and upon the Upper Keys. Carr's (1952.178) specimen from 
Card Sound, Dade County, may be an intergrade or, judging from 
the blotchy head markings, may represent M. t. rhizophorarum. 
Determination cannot be made from the photograph, and the specimen 
cannot presently be located. M. t. tequesta is known from Volusia 
County, Florida and M. t. centrata occurs as far south as Glynn County, 
Georgia. Intergrades between these two forms are expected in the 
intervening area. Johnson (1952:100) reported a specimen of M. t. 
rhizophorarum from Key Island, south of Naples, Collier County, 
Florida. I have not examined this individual, but on geographic grounds 
it would be expected to be referrable to M. t. macrospilota. Johnson's 
comment that his specimen represents an immigrant M. t. rhizophorarum 
into an otherwise pure population of M. t. macrospilota is a possibility. 
Specimens examined (except para types of M. t. tequesta) — M. t. 
centrata : South Carolina, Charleston Co., nr. Charleston, 1 ; Cooper Eiver, 
North Charles, 1; Charleston, 4; Morris Island, 8; Sol Legare Flats, 7.7 
Schwartz — The Diamondback Terrapins 
163 
mi. SSW Charleston, 4; Stono Eiver, Edgevvater Park 1; Folly Island, 6; 
Clark's Sound, James Island, 2; Clark's Sound, Folly Eiver, 3; Edisto 
Island, 1; Beaufort Co., Parris Island, 1. Georgia, Chatham, Co., Savan- 
nah, 3; Glynn Co., no other locality, 6. M. t. tequesta: Florida, Brevard 
Co., nr. Melbourne, 2; nr. Merritt Island, 14. M. t. rhizophorarum: 
Florida, Monroe Co., Planter, Key Largo, 1 ; Marquesas, 2. M. t. 
macrospilota: Florida, between Dixie and Levy cos., mouth of Suwannee 
Eiver, 12; Levy Co., Cedar Key, 7; Pinellas Co., Passagrille, 1; Gulf port, 
3; Eillshorough Co., no other locality, 1; Manatee Co., Bradenton, 1; 
Collier Co., Marco Island, 4; 3.3 mi. SW Eoyal Palm Hammock State 
Park, Ij Monroe Co., Key West ('?), 1. 
LITEEATUEE CITED 
Carr, Archie F. 1946. Status of the mangrove terrapin. Copeia, 3:170-2. 
, 1952. Handbook of turtles. Comstock Publishing Associ- 
ates, Ithaca, N. Y., i-xv, 1-542. 
Fowler, Henry W. 1906. Some cold-blooded vertebrates of the Florida 
Keys. Proc. Acad. Nat. Sci. Phila., 59:77-113. 
Hay, W. P. 1905. A revision of Malaclemmys, a genus of turtles. Bull. 
XJ. S. Bureau Fish., 24:1-20. 
Johnson, William E. 1952. Eange of Malaclemys terrapin rhizophorarum 
on the west coast of Florida. Herpet., 8(3):100. 
TABLE 1. 
15 M. t. 1 M. t. rhiso- 
20 M. t. centrata 11 M. t. tequesta macrospilota phorarum 
Carapace 
170.0 (140-192) 
180.4 (161-200) 
178.7 (167-194) 
172 
length 
Plastral 
153.2 (125-176) 
160.5 (144-179) 
160.7 (134-177) 
155 
length 
Anterior 
38.1 (32.8-43.4) 
43.5 (37.5-48.9) 
40.7 (32.5-44.8) 
42.6 
lobe length 
Middle 
50.7 (41.1-61.3) 
53.0 (44.7-61.1) 
55.2 (43.5-64.4) 
54.1 
lobe length 
Posterior 
63.5 (50.9-74.8) 
64.3 (57.9-72.6) 
64.1 (55.1-70.0) 
57.8 
lobe length 
Head width 34.7 (28.4-42.0) 
35.4 (32.6-38.6) 
36.2 (30.0-39.5) 
32.0 
Depth 
64.4 (56-75) 
72.2 (64-80) 
72.0 (59-82) 
68 
Width pos- 
81.1 (69.5-90.2) 
84.7 (70.5-94.2) 
82.4 (71.5-89.7) 
73.4 
terior lobe 
Width 
46.2 (37.9-54.4) 
50.6 (44.1-57.0) 
52.9 (41.0-58.7) 
51.7 
bridge 
Carapace 
width 
D/PLL 
124.3 (111-141) 
137.0 (119-152) 
134.4 (110-145) 
122.2 
1.02 (.92-1.16) 
1.12 (1.07-1.19) 
1.12 (.99-1.23) 
1.18 
CW/PLL 
1.99 (1.81-2.33) 
2.13 (1.99-2.26) 
2.09 (1.99-2.23) 
2.11 
Table 1. Measurements and ratios (means and extremes) of female 
specimens of four subspecies of Malaclemys terrapin. Abbreviations: 
D, depth ; CW, carapace width ; PLL, length of posterior lobe of plastron. 
164 Proceedings of the Biological Society of Washington 
TABLE 2. 
1 M. t. 9 M. t. 1 M. t. rhi- 
3 M. t. centrata tequesta macrospilota zophora/rum 
Carapace 
120.1 (112.8-128.6) 
119.4 
128.0 (109.4-143.9) 
117.0 
length 
Pastral 
102.4 1 
[91.4-110.1) 
99.4 
110.7 (93.9-122.7) 
97.7 
length 
Anterior 
25.9 
(24.0-27.3) 
26.0 
28.8 (23.7-31.6) 
27.0 
lobe length 
Middle 
33.4 
(29.8-37.1) 
30.5 
37.0 (30.6-50.2) 
32.1 
lobe length 
Posterior 
43.9 
(37.8-47.3) 
42.7 
45.4 (39.0-50.2) 
38.4 
lobe length 
Head width 
21.7 
(20.7-23.0) 
21.6 
23.6 (20.6-27.1) 
20.5 
Depth 
43.7 
(42-46) 
45 
47.3 (41-53) 
40 
Width pos- 
53.9 
(50.0-57.2) 
50.0 
57.6 (49,7-64.4) 
49.6 
terior lobe 
Width 
30.0 
(25.7-33.2) 
28.4 
35.4 (29.9-40.3) 
33.8 
bridge 
Carapace 
87.4 
(77.0-93.1) 
92.8 
95.2 (82.9-107.0) 
87.0 
width 
D/PLL 
1.00 (.91-1.10) 
1.05 
1.04 (.94-1.11) 
1.04 
CW/PLL 
1.99 
(1.97-2.04) 
2.17 
2.10 (2.05-2.17) 
2.27 
Table 2. Measurements and ratios (means and extremes) of male speci- 
mens of four subspecies of Malaclemys terrapin. Abbreviations in Table 1.