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Natural History Note - Polydactyly in Agama agama


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Polydactyly found in female specimen of Agama agama
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Herpetological Review 52(4), 2021
on the basis on visual characteristics as a Salt Marsh Greenhead
(Tabinus cf. conterminus) and was scavenging at an open wound
beneath the ear (Fig. 1). We infer the horsefly was present, and
presumably feeding for at least 2 min while we examined the
crocodile. We suspect the horsefly opportunistically targeted the
open wounds of this C. acutus given that the exposed area pro-
vided easier access for the proboscis to penetrate the flesh.
To our knowledge, this is the first record of Tabinus cf. con-
terminus parasitizing a crocodilian, in addition to the first record
of tabanid ectoparasitism of C. acutus in Honduras. Previous re-
cords of tabanid crocodilian ectoparistism include observations
in Mexico and Costa Rica (Tellez 2013, op. cit.). Tabanids are
likely generalist and opportunistic ectoparasites of crocodilians,
along with other dipteran insects (Tellez 2013, op. cit.). Arthro-
pod ectoparasites of crocodilians feed on areas that allow their
proboscis to easily penetrate the tough skin of crocodilians, such
as around the eyes, softer areas around the legs, or as in our ob-
servation, around or in open wounds (Tellez 2013, op. cit.).
Special thanks to Ely Augustinus at the Bay Islands Conserva-
tion Association for logistics and to Instituto Nacional de Con-
servación y Desarrollo Forestal, Áreas Protegidas y Vida Silvestre
(ICF), Tegucicalpa, Honduras, for granting permission to gather
biological data.
MARISA TELLEZ, Crocodile Research Coalition (e-mail: marisa.tellez@; TOM W. BROWN, Kanahau Utila Research and Conservation
Facility, Isla de Utila, Islas de la Bahia, Honduras (e-mail:;
ANDREA IZAGUIRRE, Bay Islands Conservation Association (BICA), Isla de
Utila, Islas de la Bahia, Honduras (e-mail:
AGAMA AGAMA (Common Agama). POLYDACTYLY. Polydac-
tyly, the addition of an extra phalange, has been commonly re-
ported in mammals, amphibians, and birds (e.g., Hollander and
Levi 1942. J. Hered. 33:385–391; Bishop and Hamilton 1947. Sci-
ence 106:641–642; Dunaway 1969. Am Midl. Nat. 82:244–247) but
is not as commonly reported in reptiles (Pelegrin 2007. Cuad. de
Herpetol. 21:115–116). It has not yet been recorded in the fam-
ily Agamidae, and herein I report on polydactyly in a museum
specimen of Agama agama.
During a review of A. agama specimens at the Amphibian and
Reptile Diversity Research Center, University of Texas at Arling-
ton (UTA), I found an example of polydactyly in an adult female
(UTA R-31247: 10 cm SVL) collected on 28 October 2010 from the
Meme Division headquarters building in the southwest province
of Cameroon (4.833°N, 9.333°E; WGS 84). This lizard had an extra
digit on the anterior left foot below the interior most two digits
and appears to be fully formed including a nail (Fig. 1).
There are multiple causes of polydactyl malformations in-
cluding genetic factors (Moore et al. 2007. Am. J. Primatol.
69:1105–1118), predation or parasitism (Johnson et al. 2006.
Ecology 87:2227–2235), or inadequate conditions during embryo
development (Frye 1991. Reptile Care: an Atlas of Diseases and
Treatments. T.F.H. Publications, Neptune City, New Jersey. 636
pp.), and in this case the source is unknown. As this specimen
was found as an adult, the digit likely didn’t have a negative im-
pact on locomotion or feeding. Polydactyly has been reported in
at least seven lizard families, and to my knowledge, this is the
first report in Agamidae.
CAROLINE HONAN, 808 North Pine Street, Hammond, Louisiana
70402, USA; e-mail:
CANNIBALISM. Cannibalism is known in many reptiles (Polis
and Myers 1985. J. Herpetol. 19:99–107). However, it seems rare
and of limited ecological importance in most species because
instances of cannibalism are rarely recorded in wild animals
(Maritz et al. 2019. Ecology 100:e02522). Here, we report of an
Fig. 1. Agama agama from Cameroon exhibiting polydactyly where
the extra digit on the front left foot is visible beneath the most inte-
rior phalange.
Fig. 1. Intraspecific predation event of an adult male Agama plani-
ceps on a juvenile conspecific in Namibia. The male chewed on the
head (A) and legs (B) of the dead body but seemed unable to separate
it into smaller parts.
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