A cryptic new species of Indigo Snake (genus Drymarchon) from the Florida Platform of the United States
Author
Krysko, Kenneth L.
Author
Granatosky, Michael C.
Author
Nuñez, Leroy P.
Author
Smith, Daniel J.
text
Zootaxa
2016
4138
3
549
569
journal article
10.11646/zootaxa.4138.3.7
80cf4fb0-6c8e-4acf-ae03-b9504ff9bab6
1175-5326
256358
C7391621-50DB-4070-9BCF-3D00B49F291C
Drymarchon couperi
(
Holbrook, 1842
)
Eastern Indigo Snake
(
Figures 8–9
)
Coluber couperi
Holbrook, 1842
Georgia
couperi
Baird & Girard 1853
Spilotes couperi
(part)
Cope 1860
Spilotes corais couperii
(part)
Lönnberg 1894
Compsosoma corais couperii
(part)
Cope 1900
Spilotes corais couperi
(part)
Brown 1901
Drymarchon corais couperi
(part)
Amaral 1929
Drymarchon couperi
(part)
Conant & Collins 1991
Holotype
.
Academy of Natural Sciences of Drexel University (ANSP 3937); although there is no known collector, locality, nor date assigned to this specimen, it is presumably collected by J.H. Couper (
McCranie 1980
), from the Altamaha River (
Baird & Girard 1853
), Wayne County,
Georgia
,
USA
(
Schmidt 1953
).
FIGURE 8.
Holotype (ANSP 3937) of Eastern Indigo Snake,
Drymarchon couperi
, presumably from Wayne County, Georgia. A) dorsal and B) ventral views.
Etymology.
Drymarchon
is derived from the Greek
Drymos
(meaning Oak Coppice or Forest) and
archos
(meaning Commander or Chief), referring to it being the chief of the oak woodland. The species epithet
couperi
is derived from the surname of J.H. Couper, who supposedly collected the
holotype
specimen.
Distribution.
Occurs from southeastern
Georgia
, southward into
Florida
from Suwannee and Alachua counties, southeastward to Marion, Osceola, and Indian River counties (
Fig. 7
).
Diagnosis.
Drymarchon couperi
is distinguished by a suite of molecular and morphological features, including relatively longer and deeper head dimensions, longer and shallower 7th infralabials, and longer temporal scales. Overall, the presence of a longer and shallow 7th infralabial scale provides the best univariate predictor for this species (
Table 3
;
Fig. 5
). Based on both DNA (
Krysko
et al.
2016
) and morphology (specimens examined in this study) this species includes populations from southeastern
Georgia
southward along the Atlantic coast to central peninsular
Florida
.
Description of
holotype
.
Adult male; Total Length
163.1 cm
; Snout-vent Length
133.1 cm
; Tail Length 30.0 cm; Head Length
51.3 mm
; Head Width
25.2 mm
. The relative head length (geometric shape variable; see
Tables 2
and
3
) is short (3.80) and relative head height is narrow (1.98). Supralabials 8/8 (left/right); Infralabials 9/9; Oculars 1+2/1+2; Temporals 2+2/2+2 (divided). The 7th infralabial is relatively long (0.65) and narrow (0.26) (geometric shape variable; see
Tables 2
and
3
) and the temporal scale is relatively short (0.78). The 5th and 7th supralabials are in contact with each other. Two pairs of chin shields, both of which are in contact with each other; posterior pair slightly narrower than anterior pair. The rostral visible from above, broader than high. Dorsal scales smooth and in rows at Mid-Body 17, Anterior 17 and Posterior 15; Ventral Scales 184; cloaca undivided; Subcaudal Scale Total 59 (all divided).
The specimen has faded from its likely original solid black dorsum. There is light pigment (likely reddish in real life) on the rostral, loreals, labials and chin shields that extend posteriorly onto the first three to four ventrals. The first 40 ventral scales are mottled or bicolored with different degrees of black (posteriorly) and light colored (distally) pigmentation with the remaining ventrals predominantly black. Subcaudals are entirely black.
Intraspecific variation.
Ventrals range from 182–197 (mean = 188,
n
= 30); subcaudals range from 60–67 (mean = 63,
n
= 19); supralabials are arranged 8/8 (
n
= 28) and 7/7 (
n
= 2); infralabials are arranged 9/9 (
n
= 30); temporals are arranged 2 + 2 (
n
= 30), some individuals with smaller divided scales; oculars are arranged 1 + 2 (
n
= 30); and DSR are 15-17-15 (
n
= 17), 17-17-15 (
n
= 12), and 17-19-15 (
n
= 1).