Three rare and enigmatic South American skinks
Author
Miralles, Aurélien
Author
Chaparro, Juan Carlos
Author
Harvey, Michael B.
text
Zootaxa
2009
2012
47
68
journal article
10.5281/zenodo.185813
6ee20fb6-5029-4ff7-9a65-1c01f1ba7355
1175-5326
185813
Status of
Tiliqua maculata
Gray, 1839
, and designation of a
lectotype
Gray (1839)
described
Tiliqua maculata
from
Demerara
,
Guyana
. Since its original description, various authors (
Boulenger 1887
,
Travassos 1946
,
1948
) considered it as synonymous with
Trachylepis atlantica
. Recently, Mausfeld & Vrcibradic (2002) examined two
syntypes
(NHM 1946.8.18.5–6) and strongly suspected that
T. maculata
is a species distinct from
T. atlantica
. Comparing the two species, they noted differences in number of dorsal keels, midbody scales, dorsals, ventrals and subdigital lamellae under Finger IV and Toe IV. These authors also concluded that, “
the
type
locality of
maculata
should be considered dubious
” as “
some other specimens of lizards and snakes from ‘Demerara’ collected by Capt. Sabine turned out to be restricted to certain Caribbean islands such as
St. Kitts and Nevis
and
Santa Lucia
(Underwood 1993),
” and, consequently, “
it is likely that the
type
locality of
maculata
is
St. Lucia
or
Barbados
.
” These author also speculated that
T. maculata
might be synonymous with
Mabuya falconensis
.
When
Travassos (1948: 206)
reconsidered the status of Gray’s names, he designated a
lectotype
of
Tiliqua punctata
. Regrettably, this author did not reference the specimen by its museum number stating only,
« aproveito a oportunidade para designar o exemplar macho, com
16,5 mm
depositado no Museu Británico como lectótipo […]».
This imprecise text misled some subsequent authors such as
Bauer (2003)
to conclude that a
lectotype
of
T. maculata
had been chosen. The measurement
Travassos (1948)
used to reference the specimen is its head length as indicated in the table he presents on page 207. The head measurement corresponds to the larger
syntype
; thus
Travassos (1948)
designate NHM 1946.8.27.47 as the
lectotype
of
Tiliqua punctata
Gray. He
did not designate a
lectotype
of
T. maculata
, which he considered synonymous with
T. punctata
.
During this study, we examined two of the three
types
of
Tiliqua maculata
: NHM 1946.8.18.6 (one of the two NHM
types
examined by Mausfeld & Vrcibradic, 2002) and MNHN 2932 (a third
type
housed at the MNHN) and compared them to
Trachylepis atlantica
,
Mabuya falconensis
, and various species of
Mabuya
from the Caribbean (Appendix II). Both specimens are in a very poor state of preservation, a fact noted by
Boulenger (1887)
. Fortunately,
Bocourt (1879)
illustrated and redescribed MNHN 2932 (
Fig. 7
). For this reason, it seems appropriate to designate this specimen as the
lectotype
of
Tiliqua maculata
Gray
, even if it is in a very poor state. The lecotype has 7 supralabials, the fifth below the eye, 15/15 lamellae under the fourth finger, 20/20 lamellae under the fourth toe, 37 ventrals, 58 dorsals, 32 scales around midbody, a pair of primary nuchals (secondary nuchals absent), and 5/5 supraciliaries. To avoid damaging this delicate specimen, we did not measure it, however
Brygoo (1985)
reported that it has a SVL of
219 mm
and an incomplete tail,
125 mm
.
Although number of dorsals at midbody falls within the range of
Mabuya
, Gray’s species has auricular lobules and heavily keeled dorsals. Contact between the third supraocular and frontal also excludes
Tiliqua maculata
from
Mabuya
. In the
types
, these scales narrowly contact one another (
Fig. 6
e, f), whereas they never contact one another in
Mabuya
. On the other hand, this suite of characters allies Gray’s species with the Afro-Malagasy radiation and we formally transfer it to
Trachylepis
as
Trachylepis maculata
(Gray)
new combination
.
This same suite of characters serves to distinguish
T. maculata
from
Mabuya falconensis
and its congeners from both the Caribbean and mainland Neotropics. We agree completely with Mausfeld & Vrcibradic (2002) that
T. maculata
is a species distinct from
T. atlantica
. However, we do not know if it is synonymous with a species from the Afro-Malagasy region or if it actually once occurred in
Guyana
. We often think of exotic species as a 20–21st century problem. It is certainly possible that
T. maculata
was accidentally introduced to the port of
Demerara
during the transatlantic slave trade period and has since gone extinct. Both
Bocourt (1879: 412)
and
Duméril (Duméril & Duméril 1851)
argued that
T. maculata
is most similar to the African species
T. perrotettii
: «
Nous trouvons parfaitement juste l’appréciation suivante donnée par M. Aug. Duméril (Cat. Méth. 1851, p. 159): « C’est avec l’Euprépis de Perrottet, originaire de la côte occidentale d’Afrique, que cette espèce a le plus de rapport par l’ensemble de ses caractères
» (
Bocourt 1879
).