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ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Accepted by L. Avila: 27 Mar. 2019; published: 20 May 2019 201
Zootaxa 4608 (2): 201–232
https://www.mapress.com/j/zt/
Copyright © 2019 Magnolia Press Article
https://doi.org/10.11646/zootaxa.4608.2.1
http://zoobank.org/urn:lsid:zoobank.org:pub:B26F9A0E-CD89-480E-BA23-FCE56C5854FF
A story of nasal horns: two new subspecies of Iguana Laurenti, 1768
(Squamata, Iguanidae) in Saint Lucia, St Vincent & the Grenadines,
and Grenada (southern Lesser Antilles)
MICHEL BREUIL1, BARBARA VUILLAUME2, DAVID SCHIKORSKI2, ULRIKE KRAUSS3,
MATTHEW N. MORTON4, PIUS HAYNES5, JENNIFER C. DALTRY6, ELIZABETH CORRY4,
GLENROY GAYMES7, JOANNE GAYMES7, NICOLAS BECH8, MIŠEL JELIĆ9 & FRÉDÉRIC GRANDJEAN8
1Muséum national d’Histoire naturelle, Laboratoire des Reptiles et Amphibiens, Bâtiment 30, 57, rue Cuvier, CP n° 30, 75231 Paris
cedex 05, France. Zoobank: http://zoobank.org/urn:lsid:zoobank.org:pub:4D05E6D5-81E1-4176-92DE-746DBDE33C5B
2Laboratoire Labofarm-Genindexe, 4 rue Théodore Botrel, 22600 Loudéac, France
3 Maison du Soleil, Dauphin Road, La Borne, P O Box GM 1109, Saint Lucia, West Indies
4 Durrell Wildlife Conservation Trust, Les Augres Manor, Trinity, Jersey JE3 5BP, Great Britain
5 Department of Forestry, Ministry of Agriculture, Fisheries, Physical Planning, Natural Resources and Co-operatives, Union, Saint
Lucia, West Indies
6 Fauna & Flora International, David Attenborough Building Pembroke Street, Cambridge CB2 3QZ, UK
7 Forestry Department, Ministry of Agriculture, Industry, Forestry, Fisheries and Rural Transformation, Richmond Hill, Kingstown, St
Vincent & the Grenadines
8Laboratoire Écologie et Biologie des Interactions, équipe EES, UMR CNRS 6556, Université de Poitiers, 5 rue Albert Turpin, 86073
Poitiers Cedex 9, France
9Division of Zoology, Faculty of Sciences, University of Zagreb, Rooseveltov trg 6, 10 000 Zagreb, Croatia
Corresponding author: E-mail: breuil.michel@gmail.com
Abstract
The Lesser Antilles, in the Eastern Caribbean, were long considered to have only two species in the genus Iguana Laurenti
1768: the Lesser Antillean iguana Iguana delicatissima, which is endemic to parts of the Lesser Antilles, and the Common
green iguana Iguana iguana, which also occurs throughout Central and South America. No subspecies are currently
recognised. However, herpetologists and reptile collectors have pointed out strong physical differences between some
of the island populations of Iguana iguana and those from the continent. Drawing on both morphological and genetic
data, this paper describes two subspecies of the Common green iguana Iguana iguana from the southern Lesser Antilles,
specifically the countries of Saint Lucia Iguana iguana sanctaluciae and Iguana iguana insularis from St Vincent &
the Grenadines, and Grenada. The form on the island of Saint Vincent has not been identified. The new subspecies are
described based on the following unique combination of characters: Presence of high median and medium to small lateral
horns on the snout; Small subtympanic plate not exceeding 20% of the eardrum size; Two or three scales of decreasing
size anterior to the subtympanic plate; Fewer than ten small to medium triangular gular spikes; Medium sized dewlap;
Low number of small to medium dispersed nuchal tubercles; Dark brown iris, with the white of the eye visible; Oval,
prominent nostril; Short and relatively flat head; High dorsal spines; No swelling of the jowls in reproductively active
males.
Iguana iguana sanctaluciae has in adults vertical black stripes on body and tail and a black dewlap whereas Iguana
iguana insularis is pale grey or creamy white in adults.
Both subspecies are globally threatened by unsustainable hunting (including the pet trade) and by invasive alien
species, including hybridization from invasive iguanas from South and Central America (I. iguana iguana and I.
rhinolopha, considered here as full species) that have become established in all three countries. The authors call for
stronger measures to conserve the remaining purebred Iguana i. insularis and Iguana i. sanctaluciae ssp. nov. throughout
their ranges and for further research to identify other cryptic species and subspecies of Iguana in the Lesser Antilles.
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Key words: Caribbean, endemism, hybridization, Iguana, introgression, Lesser Antilles, microsatellites, mtDNA,
speciation
Introduction
The islands of the Lesser Antilles curve around the Eastern border of the Caribbean Sea between the Greater Antilles
and South America and are noted for their rich diversity of endemic and globally threatened reptiles (Hedges 2018).
Iguanas are among the most iconic animals of this archipelago, but opinions on their nomenclature and distribution
have changed many times over the past few centuries.
Linnaeus (1758) described the Common green iguana as Lacerta iguana, whereas Laurenti (1768) described
the Lesser Antillean iguana as Iguana delicatissima and the common species as I. tuberculata. Both authors based
their descriptions on drawings and specimens (Breuil 2002, 2013, 2016; Pasachnik et al. 2006). Later, Wiegmann
(1834) described a third species with pronounced horns on its snout, I. rhinolopha, from Mexico. Duméril & Bibron
(1837) subsequently recognised three Iguana species, using the names I. tuberculata for the Common green iguana,
I. nudicollis for the Lesser Antillean iguana and I. rhinolopha for the horned Mexican iguana, but found only two
characters to separate I. tuberculata from I. rhinolopha.
The first mention of an iguana on the island of Saint Lucia was by Levacher (1834), but no information was giv-
en to determine the species. Breen (1844) commented that the iguanas were “an excellent sport for the native chas-
seurs (hunters)”. Bonnecour(t), a traveller in the mid-19th Century, caught two specimens in Saint Lucia, which are
now housed in the Muséum National d’Histoire Naturelle (MNHN) in Paris, France (Breuil 2013, 2016). Duméril
& Duméril (1851) recognised some morphological similarities between the horned specimens from Saint Lucia and
the horned iguanas Duméril & Bibron (1837) had described in Mexico. This was corroborated by Boulenger (1885),
who considered that a stuffed specimen from Saint Lucia belonged to the “variety” rhinolopha, together with speci-
mens from Central America. Confusingly, however, Provancher (1890) reported the presence of I. delicatissima on
Saint Lucia on the basis of a stuffed specimen observed in a house (Fig. 1), but his description and drawing of the
specimen were too imprecise to confirm the species’ identity. Dunn (1934) remarked that “The reports of i. rhinolo-
pha from St Kitts and from Sta. Lucia is very strange… Possibly the horned mutation has appeared independently in
that island”. Referring to rhinolopha, Barbour (1935) considered that: “The Antillean specimens are probably based
on specimens incorrectly labelled as to locality” and added “If there really ever were iguanas on these islands, the
mongoose has exterminated them”. (Small Asian mongooses, Herpestes auropunctatus, were widely introduced to
many of the Caribbean islands towards the end of the 19th Century in an attempt to control rats and, possibly in Saint
Lucia’s case, the venomous snake Bothrops caribbaeus: Des Vœux 1903; Nellis & Everard 1983).
FIGURE 1. Drawing by Provancher (1890) of a stuffed iguana on Saint Lucia. Provancher identified it as Iguana delicatissima
(see text), but the body and tail seem to have vertical black stripes, and there are small and scattered tubercular nape scales, and
no subtympanic plate. There is no tympanum and no nasal horns on this drawing, which also shows a forked tongue.
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Farther south, Garmann (1887) remarked “the Grenada specimens are intermediate between tuberculata and
rhinolopha. They have one prominent series of tubercles on the neck, and several scattered ones above the hind
extremities. The tubercles on the snout are not so prominent as in rhinolopha from Central America, but the arrange-
ment is the same. The tubercles on the neck are comparatively few as compared with those on Nicaraguan types”.
Later, Barbour (1914) advised “a careful revision of these two species, made with the aid of extensive collections
from many localities, will be necessary before their exact status can be settled”. He added: “That they are really
distinct I have no doubt whatever, but as yet their ranges cannot be accurately defined. Stejneger suspects that if
intermediates really do exist, they may be explained by the fact that the species have been carried by human agency
‘in innumerable instances’, and that the intermediates may be ‘hybrids from introduced stock, or because of their
geographic distribution’ (ex litt.). I favour the latter explanation, as apparently the accidental introduction of verte-
brates by human agency is a far rarer phenomenon than is often realized”. According to Dunn (1934) and Barbour
(1935), Grenada was inhabited by Iguana iguana iguana.
Following Boulenger’s lead, Dunn (1934) recognised two species in the genus Iguana: I. iguana (with subspecies
iguana and rhinolopha) and I. delicatissima. Lazell (1973) compared 139 “I. iguana” from Central and South America
and the West Indies with 29 I. delicatissima collected between Martinique and Anguilla, and detected only one consis-
tent difference between I. iguana and I. delicatissima: the existence in the former of a subtympanic plate at least 80%
as large as the tympanum. Lazell (1973) rejected rhinolopha as a subspecies because he thought that the nasal horns
were polytopic and polyphyletic characters, having observed them in iguanas from the Grenadines, Saint Lucia and
parts of Central America. Based on their morphology, Lazell (1973) recognized three groups of I. iguana in the Lesser
Antilles (Fig. 2): (1) The Northern group (Montserrat, Saba and, in the Greater Antilles, Saint Croix), distinguished
by a higher proportion of melanistic individuals, large tubercular nape scales and dorsal crest spikes; (2) The Gua-
deloupe group (present only in Les Saintes and Basse Terre in the Sixties) which were “quite ordinary, and resemble
those from northeastern South America. They may be patternless and/or grey: characteristics that are rare or absent in
other parts of the range of I. iguana”; and (3) The Southern group between Saint Lucia and Grenada, characterised by
vertical banding on the body and by nasal horns. Lazell considered the variation between the three groups to be clinal.
For example, iguanas on the islands between Saint Lucia and Grenada have few tubercular nape scales; iguanas from
Guadeloupe have more and larger ones; and those from the Northern group have very large and numerous tubercles.
Owing to their large size, striking colouration and horns, the Southern group is in demand for the international pet trade,
and individuals are being smuggled out of these counties and marketed variously under the trade names “Saint Lucia iguana”
and, from the Grenadines, “pink rhino iguana” and “white zebra rhino iguana” (Daltry pers. obs.; Noseworthy 2017).
In recent decades, this picture has been complicated by the discoveries both of hybridization between the two spe-
cies of Iguana and evidence of multiple invasions by iguanas from Latin America. When Lazell conducted his studies
in the 1960s, both I. delicatissima and I. iguana were abundant and sympatric in Les Saintes (Guadeloupe), but not
syntopic, and at that stage there was no evidence of one species displacing the other. It has since become clear that I.
iguana is an invasive alien species in the Guadeloupean Archipelago (Breuil 2002, 2003), and that frequent interbreed-
ing has taken place between I. delicatissima and I. iguana in Les Saintes, Grande-Terre and Basse-Terre, resulting in
fertile and morphologically intermediate hybrids (Breuil 2002, 2003). Breuil (2013, 2016) reported that I. iguana was
first introduced from French Guiana to Les Saintes in the mid-19th Century, and Breuil (2009) and Breuil et al. (2010)
explained how this species arrived on Basse-Terre. The unfortunate result of this introduction of I. iguana has been the
elimination of the native I. delicatissima through hybridization and competition from Terre-de-Bas and Terre-de-Haut
(Les Saintes) and Grande-Terre, a process that is continuing at present on Basse-Terre (Breuil et al. 2010; Vuillaume et
al. 2015; Breuil 2013, 2016). More recently, Iguana x Cyclura hybrids have been recorded from Little Cayman Island
(Moss et al. 2017), showing the lack of isolating mechanisms between these Caribbean genera.
From Guadeloupe, the alien iguanas have spread North and South. In the Sixties, Father Pinchon brought I.
iguana from Les Saintes to Martinique, and this invasive species now ranges over southern Martinique (Breuil
2011). Following Hurricane Luis in September 1995, dozens of iguanas were carried on rafts composed of logs,
vegetation, house debris and garbage from Guadeloupe to Antigua, Barbuda, and Anguilla (Daltry pers. obs.; Cen-
sky et al. 1998; Hodge et al. 2011): the Guadeloupe origin of these iguanas was inferred from their morphology
(Breuil 1999). Both Anguilla and Barbuda now have growing populations of non-native I. iguana (Henderson &
Breuil 2012). Additional iguanas have arrived in the West Indies as pets, putatively originating from breeding cen-
tres in Central America (Kraus 2009). These iguanas tend to be bigger than the Guadeloupean form, often with a
yellow-orange iris, flat median horns on their snouts, big tubercular nape scales and a very big subtympanic plate.
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204 · Zootaxa 4608 (2) © 2019 Magnolia Press
FIGURE 2. Distribution of the three iguana groups identified by Lazell (1973). Based on a clinal variation of their morphology,
Lazell (1973) identified at the beginning of the Sixties 3 groups of the Common Iguana Iguana iguana that he thought to be
native in Lesser Antilles. At that time, the central group was known to be present only in Guadeloupe (Les Saintes, Basse-Terre
and Grande-Terre). This group is not native and is the descent of invasive common iguanas from French Guiana (Breuil 2016;
Vuillaume et al. 2015). Now, however, alien iguanas from Central and South America are present throughout most of this region
(van den Burg et al. 2018) except Saint Christopher and Nevis, Petite Terre and some satellites of Saint Barthélemy, Anguilla,
and Martinique.
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During the breeding season the males are often bright orange. These invasive alien iguanas have recently become
established in the wild in Saint Martin, Saint Barthélemy, Martinique and Saint Lucia in the Lesser Antilles (Breuil
2013, 2016). Besides being transported as pets and by storms, invasive iguanas have also spread as stowaways. In
2018, for example, hybrid iguana x delicatissima were detected for the first time near the main port in Dominica,
leading local conservationists to infer that I. iguana had recently arrived with shipping containers from other Carib-
bean islands (Jeanelle Brisbane, WildDominique, pers. comm.). In addition to having become the greatest threat to
the Critically Endangered I. delicatissima in the Lesser Antilles (van den Burg et al. 2018), the invasive I. iguana
have severe negative impacts for other wildlife and humans on other islands, e.g. Puerto Rico, the Caymans and
Dominican Republic (Pasachnik et al. 2012; Falcón et al. 2012, 2013; M. Goetz, pers. comm.).
Invasive alien I. iguana were reportedly smuggled as juveniles into Saint Lucia in the late 1980s. Credible
reports of free-living hatchlings in the vicinity of Soufriere (Southwest Saint Lucia) date back to 2007, putatively
having escaped from a cage in the grounds of a hotel in Soufriere despite warnings from the Forestry Department to
keep the animals and their offspring well secured. As the invasive iguanas began to multiply in spite of efforts by the
Forestry Department and Durrell Wildlife Conservation Trust to catch and cull them, the native iguana population
has become threatened by possible hybridization and competition (Morton & Krauss 2011; Krauss et al. 2014). At
the time of writing, the invasive iguana population is growing in Southwest Saint Lucia, while the indigenous iguana
population is less than 15 km away, in the Northeast. The Government of Saint Lucia recognises the indigenous
Saint Lucia iguana as a distinct and fully protected species, despite it having long been regarded by the scientific
community as merely a variant of Iguana iguana.
The status of the iguanas in Grenada and St Vincent & the Grenadines is less well understood because iguanas
in both countries have long been regarded as a single, relatively abundant game species that can be hunted during
the open season and freely transported by hunters and buyers within their respective borders. Specimens examined
by the authors indicate that invasive I. iguana from Central and South America have invaded and multiplied on the
larger islands at least, including the main islands of Grenada and St Vincent. Unaware of the possible diversity in
iguana taxa, in 2005 the St Vincent & the Grenadines Forestry Department relocated 260 indigenous iguanas from
Palm Island to the nearby Tobago Cays (also in the Grenadines) and the Kingstown botanical gardens on Saint
Vincent in response to complaints from the owners of a resort on Palm Island that the iguanas were becoming a
nuisance. During the hunting season (October to January inclusive), hunters commonly collect and transport live
iguanas from the Grenadine islands to sell as bushmeat on Saint Vincent (G. Gaymes, pers. obs.).
As this narrative shows, understanding the distribution and taxonomy of iguanas in the Lesser Antilles has been
repeatedly frustrated by differences of opinion among scientists on nomenclature and diagnostic characters, the
accidental and deliberate movement of both native and invasive alien iguanas between islands, and hybridisation
between members of the genus Iguana. There have, however, been some recent breakthroughs. Breuil (2002, 2013,
2016) identified more than 15 morphological characters to reliably differentiate I. delicatissima from I. iguana (see
also Vuillaume et al. 2015). Breuil (2013, 2016) also proposed diagnostic characters to distinguish iguanas from
Central America, South America, Montserrat, Saba and Saint Lucia. Malone & Davis (2004) and Stephen et al.
(2013) provided preliminary genetic data that suggested that the Saint Lucia iguana forms an independent radiation
in the Lesser Antilles, but they did not consider the horned iguanas on islands South of Saint Lucia, such as the
Grenadines (which Lazell, 1973, had placed in the same phenotypic group as the Saint Lucia iguana). Vuillaume et
al. (2015) studied the genetic variation of iguanas in the Lesser Antilles from Saint Lucia to Saint Martin (French
West Indies). Following this work, Breuil et al. (in preparation) work on the genetic and morphological originality
of the insular population of Saba and Montserrat.
The objectives of this paper are:
[1] To clarify the taxonomic status of the iguanas of the southern Lesser Antilles using new morphological and
genetic data from Saint Lucia, St Vincent & the Grenadines, and Grenada.
[2] To present new information on the distribution, threats and ecology of this group, and recommendations for
their conservation.
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206 · Zootaxa 4608 (2) © 2019 Magnolia Press
Materials and methods
Morphological, molecular (i.e. mitochondrial DNA and microsatellites markers), and biological data were used
to characterise the iguanas of Saint Lucia, Grenada and, St Vincent & the Grenadines, and compare them to other
populations of Iguana iguana sensu lato.
Morphological analysis. The morphological characters used to examine the iguanas followed Breuil (2013,
2016), most of which are meristic characters that were easy to record from digital pictures taken by the authors of
wild individuals and from specimens at the Museum of Comparative Zoology (MCZ) in Harvard, USA, and the
Museum National d’Histoire Naturelle (MNHNP) in Paris, France.
We also examined photographs of Iguana found on the Internet using the Google Images search engine for the
islands of Saint Vincent, the Grenadines and, Grenada. The use of Internet images for taxonomic research was advo-
cated by Leighton et al. (2016) for studying spatial patterns in phenotypic traits that are objective, binary and easy to
see, irrespective of the angle, to supplement fieldwork. To identify diagnostic characters, we retained only pictures that
reported precise localities, and eliminated areas known to have iguanas introduced from Central and South America.
Molecular analysis. Collection and preparation of genetic material.
Genomic DNA was isolated from 39 specimens from tissue, shed skin and/or blood samples, using the QIAamp
DNA Mini Kit (QIAGEN, Deutschland) and following the manufacturer’s recommendations (Table 1). Not all
specimens were used for both mtDNA and microsatellites analysis. Samples from the Lesser Antilles were collected
by the authors and from French Guiana by François Catzefis (CNRS, France) and Benoît de Thoisy (Institut Pasteur,
Cayenne, French Guiana).
Mitochondrial DNA (ND4). 903 base pairs (bp) of the ND4 mitochondrial DNA gene were amplified using
primer pair 5’-CAC CTA TGA CTA CCA AAA GCT CAT GTA GAA GC-3’ and 5’-GCT TCT ACA TGA GCT TTT
GGT AGT CAT AG-3’. A Qiagen multiplex PCR kit was used to conduct each PCR, with a total reaction volume
of 25 µL containing 20 ng DNA template, 12.5 µL Qiagen PCR Master Mix, 2.5 µL Qiagen Q-solution, and 2.5 µL
primer mix at 10 µmM each. PCR reactions were carried out in a SimpliAmp thermal cycler under the following
conditions: initial denaturation at 95°C for 15 min, followed by 35 cycles of denaturation at 95°C for 30 s, annealing
at 52°C for 30 s, and extension at 72°C for 90 s, with a final extension step at 60°C for 30 min. The amplification
was verified by electrophoresis using LabChip GX Analyser (Caliper Life Sciences, USA) and successful PCR
products were then vacuum-purified using MANU 30 PCR plates (Millipore) before being sequenced using the
ABI Big-Dye Terminator v3.1 Cycle Sequencing Kit (Thermo). Cycle sequencing reactions were finally purified
with Sephadex G-50 Fine (GE Healthcare) and sequenced on an ABI 3130xl DNA sequencer (Applied Biosystems).
Sequence chromatograms were analyzed in SEQUENCHER (v5.3; Gene Codes Corp., Ann Arbor). Sequence align-
ment was prepared with MAFFT (v7.187; Katoh et al. 2005). For comparisons we chose a 340-bp fragment of the
ND4 locus common to all our specimens.
Microsatellites. This data set comprised 36 individuals representing seven insular and continental populations
(Table 1). A panel of 16 microsatellite markers were amplified as described by Valette et al. (2012) and Vuillaume
et al. (2015).
Phylogenetic analysis. For ND4 analysis, we aligned our ND4 sequences from the 21 specimens sampled by
the authors (Table 1) with GenBank sequences obtained from previous studies (Malone et al. 2000; Malone & Davis
2004; Stephen et al. 2013; Martin et al. 2015). Phylogenetic trees were constructed using the Maximum Likelihood
(ML) and Bayesian Inference (BI): The best-fit evolutionary model was calculated using the Bayesian Information
Criterion in jModelTest2 (version 2.1.6; Darriba et al. 2012) while the ML analysis was conducted in MEGA6
(Tamura et al. 2013) based on the best-model obtained in jModeltest. Initial tree(s) for the heuristic search were
obtained by applying the Neighbour-Joining method to a matrix of pairwise distances estimated using the Maximum
Composite Likelihood (MCL) approach. A discrete Gamma distribution was used to model evolutionary rate dif-
ferences among sites (5 categories). The BI was performed using MrBayes 3.2 (Ronquist et al. 2012) on the Cipres
Science Gateway. Two independent runs with four MCMC chains were carried out for 50 million generations.
The temperature parameter was set to 0.2 and chains were sampled every 5,000 generations. The first 12.5 million
generations were discarded as burn-in. The effective sample sizes of parameters were checked using TRACER 1.5
(Drummond & Rambaut 2007) and the convergence of runs was checked using AWTY (Nylander et al. 2008). Sup-
ported nodes in phylogram were indicated with bootstrap values P ≥ 70 in ML and posterior probabilities (pp) values
≥ 0.95 in BI.
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TABLE 1. Genetic samples
Locality/Status Microsatellites ND4 GenBank
SAINT LUCIA
Soufriere/ Alien iguanas from Central America IGU43
IGU44 IGU44 MK687388
IGU45
IGU46 IGU46 MK687389
IGU47 IGU47 MK687390
IGU49
IGU50 MK687391
IGU51
IGU52 IGU52 MK687392
Grand Anse/ Native iguanas IGU53 IGU53 MK687393
IGU55 IGU55 MK687394
IGU56 IGU56 MK687395
IGU57 IGU57 MK687396
Louvet/ Native iguanas IGU58 IGU58 MK687397
IGU59
IGU60
IGU61
IGU62
IGU63 IGU63 MK687398
IGU64
IGU65 MK687399
IGU67
IGU68
IGU69
IGU70
IGU71
IGU72
ST VINCENT & THE GRENADINES
Union Island/ Native iguanas IGU73 IGU73 MK687400
IGU74 (skin) MK687401
Palm Island/ Native iguanas IGU75 IGU75 MK687402
IGU76 IGU76 MK687403
IGU77 IGU77 MK687404
FRENCH GUIANA
Trois-Sauts/ Native IGU78 IGU78 MK687405
IGU79 IGU79 MK687406
IGU81
French Guiana/ Native IGU82 IGU82 MK687407
IGU83
IGU84 IGU84 MK687408
IGU85
The Median-Joining (MJ) haplotype network (Bandelt et al. 1999) was constructed to analyze inter- and intra-
specific relations among Iguana lineages. The MJ network was calculated and drawn using PopART (Population
Analysis with Reticulate Trees) v1.7 (Leigh & Bryant 2015).
Genetic diversity. We tested departures from Hardy-Weinberg expectations and linkage disequilibria using
exact tests based on the Markov chain (1,000 permutations) with the software fstat v. 2.9.3.2 (Goudet 2001). We
adjusted the levels of significances for multiple tests using the standard Bonferroni correction (Rice 1989). We
assessed the polymorphism over all loci for each population, computing allelic richness (AR), expected heterozy-
gosity (He), allelic frequencies and inbreeding coefficient (Fis) (Weir & Cockerham 1984) using fstat v. 2.9.3.2
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208 · Zootaxa 4608 (2) © 2019 Magnolia Press
(Goudet 2001) with 1,200 permutations. The allelic frequencies allowed us to deduce private alleles for each popu-
lation.
Genetic structure. We estimated pairwise fixation index (FST) values between populations (Weir & Cockerham
1984) using fstat v. 2.9.3.2 (Goudet 2001). Their associated significance was computed and tested using global
tests implemented in fstat v. 2.9.3.2 (Goudet 2001) with a level of significance adjusted for multiple tests using the
standard Bonferroni correction. In addition, relationships among populations were evaluated with a Factorial Cor-
respondence Analysis (FCA) based on individual genotypes and using the FCA procedure implemented in genetix v.
4.05.2 (Belkhir et al. 2004). We also accessed the genetic structure using the individual-based approach implement-
ed by the software structure (Pritchard et al. 2000). This Bayesian clustering approach estimated both the number
(K) of genetic cluster(s) and the admixture coefficient of individuals to be assigned to the inferred clusters. We
choose the admixture model and the option of correlated allele frequencies among populations. As recommended
by Evanno et al. (2005), we replicated 20 independent runs for each value of K (with K varying from 1 to 10) with
a total of 1 million iterations and a burn-in of 10,000. To determine the number of genetic clusters from structure
analyses, we used the structure harvester program (Earl & VonHoldt 2011) to compare the mean likelihood and
variance per K values computed from the 20 independent runs.
Systematic analysis. Based on morphological and genetic analysis, the Southern group of iguanas first identi-
fied by Lazell (1973) is herein recognized as two new subspecies one endemic to St Vincent & the Grenadines,
and Grenada and the other one endemic to Saint Lucia. As a consequence, the continental South American clade is
herein considered as the nominative subspecies. The form of I. iguana on St Vincent remains unverified due to lack
of known pure-bred specimens from here.
These two new subspecies (Figs 3-11) are characterized by the following combination of features and fit Lazell’s
Southern group:
– Presence of median and lateral horns on the snout that are generally enlarged at the base;
– Small subtympanic plate, not exceeding 20 % of the high of the tympanum;
– Two or three scales of decreasing size anterior of the subtympanic plate;
– Not more than 8 small to medium triangular gular spikes, exceptionally 10;
– Dewlap of medium size;
– Low number of small to medium dispersed nuchal tubercles;
– Dark brown iris (never yellow to orange), with the white of the eye visible except in the juveniles;
– Oval prominent nostril, sometimes triangular;
– Short and relatively flat head;
– High dorsal spines;
– No swelling of the jowls in reproductively active males.
– Body of juveniles and young adults is predominantly bright green with 6-8 black vertical bands. The body be-
comes very pale (almost white or cream white) in old individuals and the vertical bands either fade (subspecies
insularis) or remain black (subspecies sanctaluciae).
– Black bands on the tail, which typically remain conspicuous throughout life.
Iguana iguana insularis nov. ssp.
Grenadines horned iguana, pink rhino iguana
Figs. 3–6.
Holotype. The holotype of Iguana iguana insularis housed in MCZ under the numbers X-17620/R-79057 (Fig. 3).
This specimen was caught by James Lazell on Bequia, St Vincent & the Grenadines (10 April 1964).
Sex: Undetermined.
Age: Young, possibly 2 years old, based on its size.
Morphological measurements: Total length: 51.5 cm, SVL: 13.5 cm, tail length: 38 cm. Height and width of
the left subtympanic plate: 3.2 mm, 4.3 mm.
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FIGURE 3. Holotype of Iguana iguana insularis ssp. nov. MCZ X-17620/R-79057 © Museum of Comparative Zoology, Har-
vard University. © President and Fellows of Harvard College. Specimen in alcohol with discolouration. Annotations: 1. Small
size of subtympanic plate ± 10-20% of the eardrum. 2. Two or three scales of decreasing size anterior to subtympanic plate.
3. Juxtaposed elongated sublabial scales 5. Median and lateral horns on the snout. 6. Horns with enlarged bases. 7. Oval and
prominent nostrils. 9. Flat and triangular gular spikes. 10. Six gular spikes. 11. Scattered nuchal tubercles. 12. Low number of
nuchal tubercles. 13. Small size of nuchal tubercles. 15. Dewlap of medium size.
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FIGURE 4. Examples of adult male Iguana iguana insularis ssp. nov. A. Adult male (Palm island) sequenced under the number
IGU75 (SVL 41 cm); B and C, adult male (Palm Island) sequenced under the number IGU77 (SVL 45 cm) (Palm Island). An-
notations: 1. Small size of subtympanic plate ± 10-20% of the eardrum. 2. Two or three scales of decreasing size anterior to
subtympanic plate. 3. Juxtaposed elongated sublabial scales. 4. No apparent swelling of the jowls in breeding males. 5. Median
and lateral horns on the snout. 6. Horns with enlarged bases. 7. Oval and prominent nostrils. 8. Brown eyes with visible white.
9. Flat and triangular gular spikes. 10. Seven or eight gular spikes. 11. Scattered nuchal tubercles. 12. Low number of nuchal
tubercles. 13. Small size of nuchal tubercles. 14. Orange in dorsal scales in breeding animals. 15. Creamy white dewlap of me-
dium size. 16. Creamy white body with faint to no black banding in old individuals.
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FIGURE 5. Nasal horns of Iguana iguana insularis ssp. nov. View of the snout of IGU75 (A) and IGU77 (B) from Palm Island
(same individuals as Fig. 4). Annotations: 0. Frontal scale not developed into a horn. 1. Median horns with enlarged bases. 2.
Lateral horns. 3. Oval prominent nostril. Note the differing forms and disposition of cephalic scales, and that IGU75 (a younger
male) has flat scales whereas IGU77 (an older, larger male) has more prominent scales.
Meristics: Number of gular spikes, 5 medium + 2 small. Number of dorsal spikes to cloaca: 54 ± 1.
Paratypes. Two other young specimens MCZ X-17619/R-79056 and X-17621/R-79058) from the same loca-
tion and the same collector.
Diagnosis of Iguana iguana insularis (Figs 4, 5). We define the typical morphology of this new taxon based on
our own observations on both adults and juvenile specimens on Palm and Union Islands (St Vincent & the Grena-
dines), complemented by the specimens from MCZ R-79056-57-58 collected on Bequia (also in St Vincent & the
Grenadines) and R-79747 from Sandy Bay, Grenada. The latter four are young individuals with SVL from 128 mm
to 135 mm, and thus lack some details specific to adults.
The iguanas from the Grenada Bank, including the Grenadines, are characterised by the following association
of characters in adults compared with iguanas from Saint Lucia (I. iguana sanctaluciae ssp. nov., see below).
– In most old adults (both males and females), the green colouration and black bands fade to an almost uniform
light cream to nearly white, except on the posterior end of the tail where the black banding persists;
– In old adults, the head is nearly light cream to white;
– The dewlap is predominantly white but may have some black scales;
– There are no black margins on the subtympanic plate and on the sublabial scales;
– The snout has 2 to 5 median horns (usually 3 or 4) and 2 to 6 less developed lateral horns on each side;
– The horns may or may not remain black throughout the animal’s life;
– There are light yellow scales on the head and on the dewlap in old adults;
– The tips of the dorsal spikes of mature adults during the breeding season are light yellow to light orange;
– The anterior part of the dewlap is rounded.
Size. The largest purebred I. iguana insularis measured by the authors had an SVL of 45 cm (IGU77, an adult
male on Palm Island, Fig. 4). Its tail was incomplete.
Another large individual fitting the morphology of this subspecies (but not genetically tested) on Petit Bateau
had a total length of 136 cm.
Geographical distribution (Fig. 6). Of the c. 30 islands of Grenada Bank, including the Grenadine islands and
the main island of Grenada, 26 have been reported to have iguanas (Henderson & Powell 2018). The entire bank is
inferred to have been originally inhabited by I. iguana insularis but morphological (e.g. Henderson & Powell 2018,
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photograph p. 50) and genetic data indicate that several islands, including the main island of Grenada, have had
incursions of iguanas from South American and/or Central American lineages.
From our collection of photographs of specimens captured by the authors and obtained from internet searches,
it is clear that most Grenadine islands still have the indigenous white, horned and more or less black-banded pheno-
type, but there is the Central America phenotype with various hybrids among them that make it difficult to confirm
which islands still have purebred populations of this subspecies. Further genetic testing is required to accurately
map the present distribution of I. iguana insularis and invasive iguanas.
Etymology. The subspecific name refers to the numerous islands in the southern Lesser Antilles where the new
subspecies lives.
FIGURE 6. Distribution of iguanas in the Grenadine islands. Locations are mapped to the nearest 2 × 2 km square representing
groups of islands in the Grenadines. We have deliberately avoided being specific to protect the animals (see Auliya et al. 2016).
Note that there are alien iguanas on some islands and not all of the island clusters shown here have purebred populations of
Iguana iguana insularis. We have no confirmed specific localities for the main island of Grenada, although a museum specimen
(MCZ R-79747) confirms this subspecies occurred here. Henderson & Breuil (2012), Henderson & Powell (2018), Baldwin
(2012) and Baldwin & Mahon (2011), G. Gaymes and J. Daltry (pers. obs.; the Grenadines). While iguanas are present on St.
Vincent, these have not been identified to subspecies level and cannot be assumed to be identical to those on the Grenada Bank.
The grey line just south of St Vincent marks the brake between the St. Vincent Bank to the north and the Grenada Bank to the
south. The black line between Petit Saint Vincent and Petit(e) Martinique shows the political boundary between St. Vincent and
the Grenadines to the north and Grenada to the south. The Grenadine islands form an archipelago from the south of St. Vincent
to the north of Grenada.
Iguana iguana sanctaluciae nov. ssp.
Saint Lucia horned iguana
Figs 7–11.
Holotype. The holotype of Iguana iguana sanctaluciae housed in MNHN Paris under the number MNHN2362 and
collected by Bonnecour(t) between 1850–1851. (Fig. 7)
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FIGURE 7. Holotype and paratype of Iguana iguana sanctaluciae. The holotype MNHN2362 (A, C, D, E) and the paratype
MNHN1996.8276 (B) Both specimens collected by Bonnecour(t) in 1850-51 in Saint Lucia. Note the nasals (median and lateral
horns), the small subtympanic plate, the low number of small nuchal tubercles, the 7 gular spikes, the prominent oval nostril,
the banded body.
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FIGURE 8. Ontogenetic change in colour of Iguana iguana sanctaluciae. Young male (A), old male (B). Annotations: 1. Small
subtympanic plate ± 10% of the eardrum. 2. Two or three scales of decreasing size anterior to subtympanic plate. 3. Low number
of sublabial scales with black margins. 4. No swelling of the jowls in breeding males. 5. Lateral and median horns. 6. Median
horns with enlarged bases. 7. Oval to rounded nostril. 8. Brown eye with the white of the eye visible. 9. Triangular gular spikes.
10. 7 gular spikes. 11. Dispersed nuchal tubercles. 12. Low number of nuchal tubercles. 13. Small size of nuchal tubercles. 14.
Orange in first dorsal spikes in breeding animals. 15. Entirely black dewlap in old adults. 16. Body and tail black and bright
green in young individuals and very light green to almost pale greenish grey in old adults. Old individuals may look nearly
“black and white”. The brilliant colouration of the young male results from the flash of the camera.
This specimen is rigid, curved in its jar and it is nearly impossible to take accurate measurements.
Sex: Male
Age: Adult
Morphological measurements: total length: 132 cm; SVL: 38.5 cm; tail length 93.5 cm; height and width of
left subtympanic plate: 16.7/14.6; height and width of right subtympanic plate: 16.4/15.5, height of 4th dorsal spike:
47.5 mm.
Meristic characteristics: Number of gular spikes 7; Number of horns 2 median with very enlarged base + 3
small lateral on each side; Number of dorsal spikes to cloacae: 54
Colouration: type in alcohol with discolouration, the ground colouration is green light grey with dark banding,
6 on the body and 10 on the tail, the scale of the dewlap are dark or half dark, the dorsal spikes are ochre but seem
to have lost their original colour.
Type locality: Saint Lucia, West Indies. No more information is known for this individual.
Paratype. The stuffed specimen MNHN 1996.8276 (Fig. 7) from the same island (Saint Lucia) and the same
collector.
Diagnosis of Iguana iguana sanctaluciae (Figs 7–9). Iguana iguana sanctaluciae resembles I. iguana insu-
laris, but differs by the following association of characters:
– the scales of the jowls sometimes overlap;
– there are 7 or fewer triangular gular spikes of moderate size (cf. 8 or 9 exceptionally 10 gular spikes in I. iguana
insularis);
– the vertical bands on the body are thicker, black and remain well developed in old individuals (cf. narrow bands
on the body that fade with age in I. iguana insularis);
– the dewlap is black in old individuals (cf. creamy white in I. iguana insularis);
– the subtympanic plate and the associated 2–3 anterior scales have black pigmentation on their margins;
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– Only the anterior dorsal spikes are orange in males (cf. most dorsal spikes have an orange hue in I. iguana insu-
laris).
Size. The largest adult male to be measured on Saint Lucia was 160 cm in length (50 cm SVL) and weighed
over 5 kg (Fig. 10). A sample of 30 adults in Saint Lucia had a mean total length of 110 cm (30 cm SVL) and mass
of 1.3 kg.
Geographical distribution (Fig. 11). The distribution of native Saint Lucia horned iguanas (Iguana iguana
sanctaluciae) and introduced alien iguanas (Iguana rhinolopha) on Saint Lucia is shown in figure 16, redrawn from
Morton & Krauss (2011) with minor updates, after an island-wide, systematic survey (Morton et al. 2007).
FIGURE 9. Horned iguanas from the Central American clade of the “rhinolopha” phenotype. Photographed from invasive
introduced populations in the Lesser Antilles: old male caught in Saint Lucia (A). young male caught on Saint Maarten (B);
Annotations: 1. Huge subtympanic plate, 2 to 3 times the size of the eardrum. 2. A half crown of sublabial scales around the
subtympanic plate and the first scale anterior to subtympanic plate. 3. Mosaic of sublabial scales. 4. Swelling of the jowls in
breeding male. 5. Generally 2-3 small median horns and no lateral horns. 6. Flat small horns. 7. Triangular nostril. 8. Yellow to
dark orange eye with not the white visible. 9. Triangular gular spikes. 10. Number of gular spikes ≥ 10. 11. Nuchal tubercles
appear to be organised in rows. 12. High number of nuchal tubercles. 13. Very large nuchal tubercles. 14. Yellow, orange to red
dorsal scales on the whole body in breeding males. 15. Variable size and colour of the dewlap but often large and not uniform
black (cf. I. iguana sanctaluciae) or creamy white (cf. I. iguana insularis). 16. Body orange to red in breeding males, green in
other individuals, and not heavily banded. This phenotype is recognised in this paper as a full species, I. rhinolopha, native to
Central America (see text).
Etymology: The subspecific name is given in reference to Saint Lucia which is the only island inhabited by this
new taxon.
Comparison to other species. Because in the field there is greatest risk of confusing the new subspecies with
invasive alien I. rhinolopha, which also has nasal horns, figures 8, 9 and 10 highlight the main morphological dif-
ferences between the anterior parts of I. iguana sanctaluciae and I. rhinolopha. The two new subspecies are distin-
guished from I. iguana iguana, I. rhinolopha (considered here as a full species, see below) and I. delicatissima by
the following combination of characters.
Colour hue and pattern. The head, body and tail are bright green in young individuals, becoming very pale
greenish grey or creamy white with age (unlike I. iguana iguana, I. rhinolopha and I. delicatissima, which vary
widely in hue but are rarely as pale). The body has 6–8 thin or thick vertical black bands (except in old adult I.
iguana insularis, in which only faint traces of the vertical bands remain). These vertical black bands are present
on the newborn I. i. sanctaluciae whereas they are generally absent in newborn Iguana iguana iguana and iguana
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rhinolopha. According to Henderson & Powell (2018), juveniles most frequently are uniform green but this point
has to be checked for Iguana iguana insularis. The tail has black bands that are conspicuous at all ages (unlike I.
delicatissima, which does not have vertical bands on the body or tail). The legs are not black even in old individuals
(unlike the indigenous iguanas of Saba and Montserrat). Although the body of pale adults may have a pinkish hue,
the body colouration of breeding males is never orange as in I. rhinolopha from Central America (Fig. 10).
FIGURE 10. Adult breeding males I. iguana sanctaluciae and I. rhinolopha. The endemic Saint Lucia horned iguana (I.
iguana sanctaluciae, photo from Grand Anse, A) is clearly different from the Central America horned iguana (I. rhinolopha:
this specimen was photographed from an introduced population on Sint Maarten by M. Yokoyama, B) by size, body proportion,
body colour, size and form of the horns, eye colouration, scalation of the jowls, and dewlap size, colour and form.
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FIGURE 11. Distribution of iguanas on Saint Lucia. Locations are mapped to the nearest 1×1 km square. Data come from
Morton et al. (2007). Grey squares, Saint Lucia endemic iguana, Black squares, alien iguana from Central America clade. “False
absences” were minimized by interviewing persons about iguana presence in grid squares confirmed independently, through
sightings and captures by us, to have iguanas present. We rejected some reported sightings of native iguanas, shown here as open
grid squares, as being iguanas captured for food or pets or reports based on misidentification (for example on the islet of Maria
Major off the far south of Saint Lucia; J. Lazell, in litt. 2010). Some of the reports that were accepted from the interior of the
northern half of Saint Lucia may also be suspect, though they are all below 300 m ASL. These patterns of distribution suggest
that the mountainous interior of Saint Lucia may create at least a partial barrier to direct east-west movements of iguanas.
With age the dewlap changes from green to entirely creamy white (I. iguana insularis) or completely black (I.
iguana sanctaluciae) as the indigenous iguanas of Saba and Montserrat, but never orange (cf. I. rhinolopha, Fig. 9).
The dorsal crest is often high, especially in males (unlike I. delicatissima), and of the same colour as the light part
of the body and often pink-orange towards the tips. The iris is dark brown, not yellow to orange, and the white part
of the eye is visible (unlike I. iguana iguana, I. rhinolopha and I. delicatissima). There is no black patch between
the eye and the tympanum, and no pink on the jowls, as in Saba and Montserrat (Breuil 2013, 2016, Breuil et al. in
prep.) but some breeding males have pale golden yellow on the jowls.
Scalation. Several scales between the nostrils are elongated to form horns (whereas nasal horns are absent from
I. delicatissima and I. iguana iguana). There are 2 to 5 horns (usually 3–4) on the axial plane, and 1 to 3 smaller
horns and sometimes up to 6 for I. iguana insularis on each side in adults (whereas lateral horns absent in I. rhino-
lopha). The horns are broad at their bases and the tallest are sometimes curved back (whereas the horns of I. rhino-
lopha are thin, straight and shorter). However, hatchlings and young juveniles of the two new subspecies have only
very small horns.
The nostrils are prominent; their openings are from oval to circular, sometimes triangular in Iguana iguana in-
sularis, looking from the side. There are some small to rarely medium conical scales on the occiput. There are 6–10
medium-sized gular spikes on the dewlap that extend to the half lower part. In adults, these spikes are triangular. A
subtympanic plate is present (cf. absent in I. delicatissima) but it is relatively small: even in old adults the diameter
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of the subtympanic plate is no more than ± 20% the height of the tympanum (cf. 2–3 times the size of the tympanum
in I. rhinolopha).
There are 2–3 scales of decreasing size anterior to the subtympanic plate, a characteristic not found in other
species systematically present in I. i. sanctaluciae and sometimes in I. i. insularis. (This trait however resembles a
feature of F1 hybrids between I. iguana iguana/Iguana rhinolopha and I. delicatissima: Breuil 2013, 2016). There
are only few tubercular nape scales: fewer than 10 in I. i. sanctaluciae and up to 20 in I. i. insularis, small, not very
prominent and dispersed, i.e. not arranged in more or less conspicuous rows as in I. rhinolopha (Fig. 10) and the
largely melanistic iguanas of Saba and Montserrat populations (I. cf. iguana). This distinguishing character is pres-
ent in hatchlings and throughout life, unlike some of secondary sex characteristics noted above.
Head. The head is relatively short and flat, and the dewlap is of medium size (cf. the large dewlap in I. rhino-
lopha). The scales anterior to the subtympanic plate overlap slightly in some individuals. The jowls do not appear
swollen even in reproductively active males (cf. very well-developed jowls in breeding male I. rhinolopha).
FIGURE 12. Phylogenetic tree. Based on mtDNA of 23 iguanas (21 from this study, 2 from GenBank). Four clades are iden-
tified. Iguana delicatissima (AF217783) serves as the outgroup. The monophyly of Lazell’s southern Lesser Antilles group,
characterised by horns, is described here as two new subspecies Iguana iguana insularis and Iguana iguana sanctaluciae. The
horned iguanas from Central America are also considered here as a full species I. rhinolopha. The sister group of I. iguana
insularis and Iguana iguana sanctaluciae is I. iguana iguana (based on specimens shown here from French Guiana). This phy-
logenetic tree shows that I. iguana iguana is present as an invasive alien species in the Grenadines (IGU74) and that there is I.
delicatissima mitochondrial DNA in some specimens of I. iguana sanctaluciae. The ML tree with the highest log likelihood is
shown. Node supports were indicated by bootstrap values from ML (>70) and posterior probability from BI (>0.95).
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Results of genetic analysis
Phylogeny. The intra- and interspecific relationships among Iguana species are shown in the phylogram (Fig. 12)
and in the Median-Joining haplotype network (Fig. 13). Four clades can be observed:
Clade 1, the most basal, corresponds to I. delicatissima (GB: AF217783), which clustered with mtDNA from
two iguanas from Grand Anse in Saint Lucia (IGU55, IGU56) that had been identified in the field as pure endemic
iguanas (see Discussion). IGU53, from the same locality, shows a haplotype that was found nowhere else.
Clade 2 corresponds to the mtDNA haplotypes shared by the alien iguanas on Saint Lucia, identified by their
phenotypes as iguanas from Central America, likely originating from the pet trade (Fig. 9). These haplotypes are
close to those of the Central American clade of Stephen et al. (2013) and Vuillaume (2012). This clade forms the
sister group of the iguanas from French Guiana (South America) and from the southern Lesser Antilles.
Clade 3 groups the Common green iguana (I. iguana iguana) from French Guiana but also contains a specimen
known only from a piece of shed skin (IGU74) found on Union Island (St Vincent & the Grenadines).
Clade 4 is consistent with our morphological analysis and shows the existence of an endemic group that inhabits
Saint Lucia and the Grenadines (Grenada Bank).
FIGURE 13. Median-Joining haplotype network. Based on 23 mtDNA sequences of Iguana (21 from this study, 2 from Gen-
Bank). Black circles are median vectors that represent extinct or unsampled haplotypes. Numbers of mutational steps are indi-
cated by hatch marks.
Genetic diversity. No linkage disequilibrium was detected after Bonferroni correction (adjusted P-value thresh-
old = 0.0004). Only 5 of the 64 population-locus combinations deviated significantly from Hardy-Weinberg expec-
tations (adjusted P-value threshold after Bonferroni correction = 0.0008). These deviations occurred for population
of individuals endemic of Saint Lucia and so seem to be inherent to it. All microsatellite loci were polymorphic with
an allelic richness (AR) ranging from 1 to 3.552 and a genetic diversity (He) ranging from 0 to 0.821 across popu-
lations (Table 2). Moreover, based on allelic frequencies, individuals introduced in Saint Lucia and those coming
from French Guiana revealed the presence of several private alleles suggesting a specific genetic signature and so
populations well genetically differentiated.
Genetic structure. Results revealed significant genetic differentiation between populations. After applying
the Bonferroni correction (adjusted P-value threshold = 0.0083), significant FST values were found between several
pairwise populations (mean FST value = 0.495) (Table 3). This significant variation was corroborated by both FCA
(Fig. 14) and the Bayesian individuals-based approach. Indeed, based on the individuals’genotypes, FCA clearly
distinguishes four different populations and, furthermore, shows the low genetic diversity within the native Saint
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Lucia population (only 7 circles are shown because many individuals from Louvet and one from Grand Anse had
the same genotypes based on 16 microsatellites). The structure and structure harvester software revealed a high-
est delta K value of 3 (Figs 15, 16). According to these results, individuals from introduced iguana populations in
Saint Lucia and those from French Guiana were mainly assigned to the first and second genetic cluster respectively
(clades 3 and 2 from the phylogram, Fig. 12). Individuals native to Saint Lucia and the Grenadine islands were
mainly assigned to the third genetic cluster (clade 4 of the phylogram). However, we can also distinguish three indi-
viduals (IGU53, IGU55, IGU56) that showed intermediate admixture coefficients, even though they were assumed
to be of pure native origin. These intermediate admixture coefficients (Fig. 16, Table 4) and FCA results (Fig. 14)
suggest hybridization has occurred in Grand Anse, where three out of the four individuals sampled are considered
as hybrids between endemic and introduced individuals from different clades. Moreover, IGU55 and IGU56 have I.
delicatissima haplotypes for ND4, and IGU53 has a unique haplotype closely related to I. delicatissima (Fig. 13).
TABLE 2. Genetic diversity parameters for each locus. Expected heterozygosity (He); number of private alleles (PA);
allelic richness (AR); and inbreeding coefficient (Fis) have been computed for each population and each locus using
FSTAT ver. 2.9.3.2 software (Goudet 2001). In italics and bold: the Fis with significant departures from Hardy-Weinberg
expectations (i.e. significantly different from 0; P<0.0008 after Bonferroni adjustment).
Saint Lucia
Introduced
Iguana rhinolopha
Saint Lucia
endemic
Iguana iguana
sanctaluciae
Grenadines
endemic
Iguana iguana
insularis
French Guiana
Iguana iguana
iguana
All populations
n 8 17 4 7 36
L2 He 0 0.265 0 0.262 0.132
PA 0 0 0 0 -
AR 1 1.647 1 1.692 1.91
Fis NA 0.778 NA -0.091 0.343
L3 He 0.125 0 0 0 0.031
PA 1 0 0 0 -
AR 1.375 1 1 1 1.768
Fis 0 NA NA NA 0
L5 He 0.690 0.272 0 0.524 0.371
PA 2 0 0 0 -
AR 2.874 1.779 1 1.99 2.738
Fis -0.448 0.351 NA -0.091 -0.063
L6 He 0.429 0.217 0 0.524 0.2925
PA 0 0 0 1 -
AR 1.930 1.559 1 1.972 2.299
Fis -0.333 0.458 NA 0.727 0.284
L8 He 0.667 0 0 0.262 0.232
PA 1 0 0 1 -
AR 2 1 1 1.692 1.453
Fis 0.5 NA NA -0.091 0.204
L9 He 0.652 0.217 0.75 0.607 0.556
PA 0 0 0 1 -
AR 2.604 1.559 2.929 2.692 2.972
Fis 0.233 0.458 0.333 -0.412 0.153
L13 He 0 0.217 0.5 0 0.179
PA 0 0 0 0 -
AR 1 1.559 1.964 1 1.975
Fis NA 0.458 1 NA 0.729
......continued on the next page
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TABLE 2. (Continued)
Saint Lucia
Introduced
Iguana rhinolopha
Saint Lucia
endemic
Iguana iguana
sanctaluciae
Grenadines
endemic
Iguana iguana
insularis
French Guiana
Iguana iguana
iguana
All populations
L14 He 0.125 0.116 0 0.143 0.096
PA 0 1 0 1 -
AR 1.375 1.353 1 1.429 1.959
Fis 0 -0.016 NA 0 -0.005
L15 He 0.393 0.059 0 0.679 0.28275
PA 1 0 0 1 -
AR 1.885 1.176 1 2.774 1.893
Fis -0.273 0 NA 0.158 -0.038
L16 He 0.81 0 0.25 0.143 0.301
PA 2 0 1 0 -
AR 3.375 1 1.75 1.429 2.06
Fis 0.824 NA 0 0 0.275
L17 He 0.548 0.224 0 0.488 0.315
PA 1 0 0 2 -
AR 1.99 1.652 1 2.275 3.055
Fis 0.478 0.475 NA 0.415 0.456
L18 He 0.339 0 0 0.533 0.218
PA 1 0 0 1 -
AR 1.786 1 1 1.998 1.667
Fis 0.632 NA NA -0.25 0.191
L19 He 0.125 0.272 0 0.524 0.230
PA 0 0 0 0 -
AR 1.375 1.779 1 1.995 2.439
Fis 0 0.351 NA -0.364 -0.004
L20 He 0.571 0.224 0 0.655 0.3625
PA 1 0 0 3 -
AR 2.348 1.652 1 2.827 3.213
Fis -0.094 0.475 NA -0.091 0.097
L23 He 0.4 0.272 0 0.821 0.373
PA 0 0 0 3 -
AR 1.909 1.779 1 3.552 3.071
Fis -0.25 0.351 NA 0.304 0.135
L24 He 0 0 0 0 0
PA 0 0 0 0 -
AR 1 1 1 1 1
Fis NA NA NA NA NA
All
loci
He 0.367 0.147 0.094 0.385 0.248
PA 10 1 1 14 -
AR 1 1 1 1 1
Fis 0.156 0.425 0.5 0.034 0.279
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TABLE 3. Pairwise Fst values for each population comparison (below diagonal) and their significance level (above di-
agonal). P-value threshold is adjusted with the Bonferroni correction, P= 0.0083.
Saint Lucia
Introduced
Iguana rhinolopha
Saint Lucia endemic
Iguana iguana
sanctaluciae
Grenadines
endemic
Iguana iguana
insularis
French Guiana
Iguana iguana
iguana
Introduced Saint Lucia - 0.0083 0.1083 0.0667
Saint Lucia endemic 0.6846 - 0.0583 0.0083
Grenadines endemic 0.6448 0.1051 - 0.0083
French Guiana 0.5048 0.5472 0.4832 -
TABLE 4. Admixture coefficient inferred by STRUCTURE software for the four studied populations.
Cluster 1 Cluster 2 Cluster 3
Introduced Saint Lucia Iguana rhinolopha 0.941 (±0.153) 0.056 (±0.151) 0.003 (±0.002)
Saint Lucia endemic
Iguana iguana sanctaluciae
0.064 (±0.142) 0.072 (±0.196) 0.864 (±0.324)
Grenadines endemic
Iguana iguana insularis
0.011 (±0.015) 0.025 (±0.025) 0.964 (±0.037)
French Guiana
Iguana iguana iguana
0.003 (±0.001) 0.994 (±0.001) 0.003 (±0.001)
FIGURE 14. Factorial Correspondence Analysis (FCA) of the genotypes of samples from four populations. Black squares:
individuals introduced in Saint Lucia (Iguana rhinolopha) [n=8] circles: individuals endemic to Saint Lucia (Iguana iguana
sanctaluciae), with white circles for individuals from Louvet (n=13) and hatched circles for individuals from Grand Anse (n=4);
white triangles: individuals endemic to Grenadines (Iguana iguana insularis), [n=4]; and grey stars: individuals from French
Guiana (Iguana iguana iguana) [n=7]. Only 7 circles are shown for the 17 ‘native’ individuals from Saint Lucia because many
individuals from Louvet and one from Grand Anse had the same genotypes.
TWO NEW SUBSPECIES OF IGUANA IGUANA Zootaxa 4608 (2) © 2019 Magnolia Press · 223
FIGURE 15. Results from the Evanno’s Method using the STRUCTURE HARVESTER software. This analysis reveals a
maximum likelihood for K=3.
FIGURE 16. STRUCTURE bar plot showing admixture coefficient of each individual to the three inferred genetic clusters.
This bar plot was produced using the distruct program (Rosenberg 2004).
Discussion
Taxonomic and systematic implications. The presence of horns on the iguanas of Central America first prompted
the description of Iguana rhinolopha, by Wiegmann (1834), based on specimens caught in Mexico, and Duméril
& Duméril (1851) and Boulenger (1885) subsequently applied the same name to iguanas from Saint Lucia because
of their horns. No other morphological traits were used to distinguish I. rhinolopha apart from a small difference
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224 · Zootaxa 4608 (2) © 2019 Magnolia Press
in number and size of spikes on the dorsal crest, identified by Duméril & Bibron (1837) based on a very small
number of specimens (Figs 9, 10). Later, with the widespread use of the subspecies concept, Dunn (1934) proposed
that rhinolopha was merely a subspecies of I. iguana, and Barbour (1935) also followed this position. This was the
consensus until the work of Lazell (1973), who considered that the presence of horns on the snout was inconsistent
and, because it occurs polytopically, he rejected the taxon rhinolopha. Lazell realised that the indigenous iguanas
on Saint Lucia possessed horns that were generally well developed on mature adult individuals, and this is also
confirmed by our observations. However, while horns can be found in Central American iguanas, they differ from
the arrangement of horns found in the Lesser Antilles as we have demonstrated in this work.
This paper describes two new subspecies of horned iguana known only from the southern Lesser Antilles. All
the indigenous iguanas from Saint Lucia, St Vincent & the Grenadines and Grenada, described herein possess me-
dian and lateral horns. Moreover they have a combination of morphological traits that makes them unique, includ-
ing: low number and small size of nuchal tubercles, small subtympanic plate, brown iris colour with the white of
the eye visible, no subtympanic swelling, colour hue and pattern of the body, etc. (Figs 4, 5, 7, 8). With about 2%
divergence in the ND4-Leu sequence, I. iguana insularis and I. iguana sanctaluciae show a level of differentiation
from I. iguana iguana from French Guiana that is within the interval of divergence of subspecies recognition among
Cyclura (Malone & Davis 2004). So, should we regard this Southern group as a full species with two subspecies,
or simply two horned differently coloured subspecies of Iguana iguana? In recent years, the subspecies concept has
become unpopular in herpetology, and almost every subspecies in the Caribbean has now been upgraded to a full
species (e.g. Breuil 2002) in accordance with the phylogenetic species concept that treats populations as separate
species if they are on separate evolutionary trajectories (see e.g. Torstrom et al. 2014), as is usually the case for
animals confined to separate islands. For example, the same basis was used by Hawlittsckek et al. (2012) for distin-
guishing species and subspecies of Comoran snakes.
As there are enough distinct and consistent morphological and genetic differences (Figs 12, 13, 14, 15) to
recognise the native southern Lesser Antillean iguanas as a full species we nevertheless chose to consider them
only as subspecies of Iguana iguana. We proceed as that to prevent too many changes in the taxonomy of the genus
Iguana but proceeding as that we loose the information that this two subspecies have a unique common ancestor.
Further research is also needed on the island of St Vincent to determine whether any purebred (i.e. non-hybrid) na-
tive iguanas remain here, and whether they belong to either of the aforementioned subspecies or a third, undescribed
subspecies.
When did this southern lineage diverge from other lineages in this genus? Studies of iguana morphology (Breuil
2013, 2016) and genetics (Stephen et al. 2013; Vuillaume et al. 2015) have shown there are at least three ancient
lineages (I. delicatissima and the iguanas of Central America and South American) in the genus Iguana, with a
genetic divergence approximated by a molecular clock of 1.29 million years for every 1% sequence divergence at
the ND4-Leu Locus (Malone et al. 2000). With approximately 10% divergence (Malone & Davis, 2004) between I.
iguana and I. delicatissima, the age of separation of these two species is therefore about 11–12 My; but according
to Hedges et al. (2015), the two lineages could have diverged as much as 22.8 My ago. If we take the lower value
of the molecular clock, I. iguana insularis and I. iguana sanctaluciae diverged about 2.2 My ago. This timeframe is
compatible with the ages of Saint Lucia and Grenada, where the oldest rocks date from the Miocene and belong to
the intermediate volcanic arc (Bouysse & Garrabé 1984; Germa 2008).
Evolution in isolation over millions of years does not automatically mean the taxa cannot interbreed. Even
the most distantly related species in the genus Iguana – I. delicatissima and I. iguana – can interbreed to produce
healthy, fertile offspring (Breuil 2013, 2016; Vuillaume et al. 2015). This is not very unusual among even more
distantly related taxa: For example, even crocodiles in the genus Crocodylus from opposite sides of the globe can
interbreed to produce fertile hybrids that have a competitive advantage (e.g. Daltry et al. 2016a). Judging from their
nesting periods (Fig. 17), there is some overlap between the breeding seasons of I. iguana sanctaluciae, I. delicatis-
sima and introduced I. iguana from South America, which might enable these species to interbreed.
Where does this leave the horned iguanas of Central America? Stephen et al. (2013) recognized two well sup-
ported genetic groups in Iguana iguana as evolutionary significant units: Central America (México to Panamá)
and South America (excluding Curaçao) and the Lesser Antilles) but declined to propose any taxonomic changes
pending further sampling across Panamá and South America and a better understanding of the basal position of the
populations of Curacao (Buckley et al. 2016). The divergence between Central and South American clades based
on ND4-Leu is about 4.3%, similar to the 4% divergence between Cyclura species (Malone & Davis 2004). We
TWO NEW SUBSPECIES OF IGUANA IGUANA Zootaxa 4608 (2) © 2019 Magnolia Press · 225
therefore accept I. rhinolopha (Wiegmann 1834) as a full species native to Central America, distinguished not only
by its unique arrangement of nasal horns but numerous other morphological and genetical characters, as shown by
Breuil (2013, 2016), Stephen et al. (2013) and Vuillaume et al. (2015). By sampling more areas across this region,
it is likely other new cryptic species or subspecies will be identified (Bickford et al., 2007; Buckley et al. 2016).
Indeed, the melanistic iguanas from Saba and Montserrat have been shown to be morphologically and genetically
distinct (Breuil 2013, 2016; Stephen et al. 2013; Vuillaume et al. 2015) and will be considered in another work.
Nevertheless, further studies elsewhere in this region are unlikely to change our conclusions regarding the original-
ity of Iguana iguana insularis and Iguana iguana sanctaluciae vs Iguana. rhinolopha and Iguana iguana iguana in
the Lesser Antilles.
FIGURE 17. Nesting periods of various iguana populations. Monthly mean precipitation is indicated in mm. Precipitation var-
ies according to altitude and aspect, but the important point is that after a 3 months incubation period, the eclosions occur at the
beginning or during the rainy season. The brackets indicate the main laying period for the different species at different insular
and continental locations. Note that the nesting period of Iguana iguana sanctaluciae overlaps the laying periods of both Iguana
delicatissima and Iguana iguana iguana, which suggests that mating periods could also overlap, potentially enabling all three
species to interbreed.
The most unexpected revelation from our genetic study is that two iguanas (IGU55, IGU56) from Grand
Anse, Northeast Saint Lucia, had delicatissima ND4 haplotypes, while a third (IGU53) had an unknown haplotype
that also clustered with delicatissima in addition to the microsatellites from both I. iguana iguana and I. rhinolopha
(Figs 12, 13, 16). The samples used to characterise the population of Grand Anse were juveniles caught 10 years
ago, when the morphological differences between the different clades of Iguana were less well understood, and
the animals were erroneously registered as pure native Saint Lucia iguanas (Table 1). As reported in our introduc-
tion, Provencher (1880) had mentioned the presence of I. delicatissima on Saint Lucia, but the only evidence was a
poorly executed drawing (reproduced in Fig. 1). Our discovery of Iguana delicatissima unique haplotypes in Saint
Lucia may be explained by either an ancient delicatissima population on Saint Lucia that persists only as a maternal
lineage or by the recent arrival of a female with this unknown haplotype from another island that has reproduced
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226 · Zootaxa 4608 (2) © 2019 Magnolia Press
with Iguana iguana sanctaluciae. Currently, however, we have insufficient data to support one or other hypoth-
esis.
Conservation status of the new subspecies. These new subspecies of iguana are at risk throughout their ranges
in the southern Lesser Antilles due to habitat loss, hunting (both for bushmeat and the pet trade) and invasive alien
species, especially alien predators and non-native Iguana species.
Of the two new subspecies described in this paper, the Saint Lucia horned iguana (I. iguana sanctaluciae) ap-
pears to be most scarce and vulnerable to extinction. These iguanas are a fully protected species under the Wildlife
Protection Act (Laws of Saint Lucia 2010), but they continue to be hunted and eaten at a significant level (Morton &
Haynes, pers. obs.) and have been illegally exported and sold to collectors overseas (J. Daltry, pers. obs.). The range
of the native iguana population on Saint Lucia is now restricted to that part of the island without good road access
(Fig. 16), putatively because of over-hunting in the more accessible areas.
Habitat conversion for development (in particular the proposed tourism developments on the three large estates
of Louvet, Grand Anse and Marquis, and the proposed North East Corridor highway) is currently considered the
most severe threat facing the remaining population. Illegal mining of beach sand threatens the iguanas’ nesting sites
and their seasonal deciduous forest habitat is also especially vulnerable to wildfires (Robbins et al. 2008). Develop-
ments in the Northeast are also likely to exacerbate threats from introduced mammalian predators: Feral cats (Felis
catus), southern opossums (Didelphis marsupialis) and small Asian mongooses (Herpestes auropunctatus) are all
known to kill hatchling iguanas in Saint Lucia (Morton et al. 2007). Mongooses also take iguana eggs, and the
mutilation of hatchlings whilst still in the nest chamber has been attributed to rats (Rattus rattus or R. norvegicus)
(Morton pers. obs.). Both feral and domestic dogs (Canis familiaris) prey on iguanas, especially nesting females that
are especially vulnerable whilst on the ground (Morton et al. 2007).
Invasive alien iguanas also pose a serious threat, having become well established in Southwest Saint Lucia.
Despite numerous efforts to catch and cull the invasive iguanas (Morton & Krauss 2011; Krauss 2013; Krauss et
al. 2014), it is proving prohibitively expensive and difficult to limit their spread and prevent contact with the indig-
enous Iguana iguana sanctaluciae in Northeast Saint Lucia (Fig. 11), especially with the risk of human-mediated
transport across the country. The alien iguanas appear to originate from the Central America clade (Iguana rhino-
lopha), characterised by its greatly enlarged subtympanic plate, yellow iris, numerous and conspicuous tubercular
nape scales, orange colouration in breeding male, huge dewlap with more than ten spikes but also small horns on
the stout (Breuil 2013, 2016). The invasive iguanas on Saint Lucia (Fig. 9) also have larger clutches than the native
species: mean clutch size for the former is 40 (n = 4 clutches) and mean clutch size for I. iguana sanctaluciae is
only 23 eggs (n = 14 clutches). The same invasive iguanas from Central America have clutch sizes of 8–75 in Puerto
Rico (Lopez-Torres et al. 2012) and 20–63 in Hawaii (McKeon 1996). It is very likely that the alien iguanas could
hybridize as suggested by the genetic analysis (Fig. 16) with and outcompete Iguana iguana sanctaluciae, leading to
its elimination (as occurred with I. delicatissima in Les Saintes, Basse-Terre and Grande-Terre: Breuil 2002, 2013,
2016; Vuillaume et al. 2015).
The status and threats to the Grenada Bank subspecies is less well understood because iguanas have been less
closely studied and existing literature on iguanas has failed to distinguish between the native and invasive alien
iguanas. Given that iguanas in general are considered to be fairly abundant and widespread on Grenada and St Vin-
cent & the Grenadines, adult iguanas may still be lawfully hunted for several months of the year (typically October
through December or January) for personal consumption and local sale (Laws of Saint Vincent & the Grenadines
1990; Laws of Grenada 1990, Henderson & Powell 2018). Unlike Saint Lucia, the national laws here do not distin-
guish between native and introduced or hybrid iguanas, nor define any populations that may not be hunted or moved
within national borders. It is therefore not uncommon for hunters to collect iguanas from the Grenadine islands
for sale on St Vincent or Grenada during the hunting season (G. Gaymes, pers. obs.). Hunting is frequent on the
uninhabited island of Baliceaux, for example, where hunters from Bequia and Saint Vincent “carry away dozens of
iguanas” (Daudin & Da Silva 2011). In this context of numerous translocations, it is uncertain how many purebred
populations of Iguana iguana insularis remain.
Not surprisingly, considering the lack of any concerted effort to prevent incursions, alien iguanas appear to have
become very widespread in Grenada and St Vincent & the Grenadines, with perhaps no purebred (i.e. non-hybrid)
native iguanas remaining anywhere on the main islands of St Vincent or Grenada. We suspect that the most intact
native populations are restricted to some of the smallest islands in the Grenadines, including Palm Island and Union
Island, where genetic samples were analysed for this study. It is noteworthy that in this context that IGU74 collected
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as a shed skin has a ND4 haplotype that clusters with Iguana iguana from South America. Like the iguanas of Saint
Lucia, even these populations are at substantial risk from invasive alien predators (dogs, cats, opossums, etc.) and
coastal deforestation and development (Daltry et al. 2016b).
Under the national laws of all three countries – Saint Lucia, St Vincent & the Grenadines and Grenada – the
export of iguanas or their products is prohibited without permits from their respective chief wildlife wardens. Fur-
thermore, on the basis that the iguanas were classified as Iguana iguana, listed on CITES Appendix II, exports have
required an export certificate from the CITES Management Authority. Nevertheless, recent years have seen a rise
in young iguanas being smuggled from these islands and sold under various trade names, including the Saint Lucia
iguana, pink rhino iguana (originating from Union Island) and white zebra rhino iguana (from the Tobago Cays).
Iguanas from Saint Lucia and the Grenadines have been offered for sale in the USA, Japan and Europe, for prices
of up to $10,000 per pair, with traders often claiming to have CITES permits, even though no such export permits
have been issued by these countries (Noseworthy 2017).
The Saint Lucia iguana (Iguana iguana sanctaluciae) is Critically Endangered under criteria B1ab(i–iii): Its
extent of occurrence is approximately 30 km2, it exists in only one location (Northeast Saint Lucia), and a continu-
ing decline is observed and projected in the (i) extent of occurrence, (ii) area of occupancy, and (iii) area, extent
and quality of habitat due to tourism developments, sand-mining, livestock grazing and other documented threats
(Daltry 2009).
The Grenadines horned iguana (Iguana iguana insularis) has been less closely studied but qualifies as Vul-
nerable and possibly Endangered under criteria B1ab(i–iii): Its area of occupancy is less than 20 km2, it exists at
not more than 10 locations (only two locations – the 9 km2 Union Island and 0.55 km2 Palm Island – have been
confirmed to have reasonably intact, non-hybrid populations) and estimates indicate continuing decline, observed,
inferred or projected, in the (i) extent of occurrence, (ii) area of occupancy and (iii) area, extent and quality of habitat
due to tourism developments, livestock grazing, bushfires and other threats (Daltry et al. 2016).
Recommendations
International trade in horned iguanas from the Grenadine islands (specifically, Union Island, Palm Island and the
Tobago Cays) and Saint Lucia has been confirmed in recent years at a level that could present a serious risk to both
subspecies. By formally describing the two subspecies, we recognise that the demand from reptile collectors could
increase (Auliya et al. 2016). We therefore recommend that as an urgent precaution the two new subspecies Iguana
iguana insularis and Iguana iguana sanctaluciae, should be placed on Appendix I of CITES at the next Confer-
ence of Parties to monitor and control illegal international trade. As an interim measure, we urge Saint Lucia, Saint
Vincent & the Grenadines and Grenada to jointly request the CITES Secretariat to place these two new subspecies
on Appendix III. This is necessary to help to ensure that iguanas cannot be sold overseas without a CITES export
permit from the country of origin.
Nationally, Iguana iguana sanctaluciae is fully protected in Saint Lucia, where the Wildlife Protection Act
distinguishes between the native Saint Lucia iguana and the (non-protected) invasive alien iguanas. We recommend
Grenada and St Vincent & the Grenadines also consider increased levels of protection for the native horned igua-
nas and ensure that any future exploitation of I. iguana insularis populations is monitored closely and sustainable.
Considering the outstanding importance of the apparently purebred and growing population of I. iguana insularis
on Palm Island (St Vincent & the Grenadines), technical assistance should be offered to the landowners to find solu-
tions to complaints that the iguanas are causing a nuisance.
Because invasive alien iguanas have already become well established in all three countries (Saint Lucia, St
Vincent and the Grenadines, and Grenada), it is also imperative to safeguard all remaining native iguana populations
from hybridisation and competition. Active biosecurity measures must be developed to prevent non-native iguanas
from successfully spreading to Northeast Saint Lucia, Palm Island, Union Island and any other areas known to have
purebred (non-hybrid) I. iguana insularis, including monitoring these native populations regularly to ensure any
incursions are detected and dealt with swiftly. Further surveys are required on St Vincent and Grenada to determine
whether any purebred native iguanas remain on these islands. If alien iguanas continue to increase unchecked on
Saint Lucia, it may be necessary to separate them from the native iguanas with a physical barrier. With this in mind,
plans are currently being developed to create a ‘mainland island’ sanctuary for native Saint Lucian wildlife, sur-
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rounded by a pest-proof fence (Saint Lucia Forests and Land Resources Department, 2015) that could potentially
conserve several hundred I. iguana sanctaluciae in strict isolation from alien iguanas.
To support all these recommendations, it will be necessary to develop illustrated identification materials for
researchers, enforcement officials and other stakeholders to reliably distinguish I. iguana insularis and I. iguana
sanctaluciae at all ages from I. iguana iguana, I. rhinolopha and other species.
Thus, we hope that the recognition of this two subspecies will ultimately facilitate their protection and conser-
vation.
Acknowledgements
This project was financed mainly by the Direction Régionale de l’Environnement et du Logement de Martinique to
study the origin of invasive Common green iguanas in Martinique and their relationships to the Saint Lucia iguana.
The genetic study formed part of Barbara Vuillaume’s Master’s degree. The genetic analyses were initially con-
ducted at Genindexe in La Rochelle (France) and completed by David Schikorski in Genindexe Labofarm (France),
which financed part of this study.
Specimens were collected from Palm Island and Union Island, in the Grenadines, by JD and GG with kind
permission from the Palm Island Resort and the St Vincent & the Grenadines Forestry Department. Fieldwork was
supported with funding from the FFI Species Fund, Disney Conservation Fund, National Geographic, US Fish &
Wildlife Service (#F18AP00796), and the St Vincent & the Grenadines Preservation Fund. We are most grateful
to Roseman Adams, Katrina Adams and other members of the Union Island Environmental Attackers for their as-
sistance. Special thanks also to F. Catzefis (CNRS, Montpellier) and Benoît de Thoisy (Institut Pasteur, Cayenne,
French Guiana), who provided samples from French Guiana and Mark Yokoyama for the picture of Iguana rhino-
lopha (Fig. 10).
All Saint Lucia samples were collected by the Durrell Wildlife Conservation Trust and the Saint Lucia Forestry
Department. Many members of the Forestry Department were closely involved in project work on the biology of
the iguana on Saint Lucia, including especially Alwin Dornelly, Timotheus Jean Baptiste, Brian James, Lyndon
John, Stephen Lesmond, Michael Bobb, Adams Toussaint, Michael Andrew, Feria Narcisse-Gaston, Rebecca Rock,
George Antoine, Mary James and Richard Regis. Martin Satney and Dunley Auguste provided much appreciated
support from the Ministry of Agriculture. Special thanks are due to Donald Anthony (Saint Lucia Forestry Depart-
ment), John Hartley and John Fa (Durrell Wildlife Conservation Trust) for developing the project work on Saint
Lucia, and most especially to Anthony ‘Seako’ Johnny for countless hours of assistance with field work and shar-
ing his extensive local knowledge. Many hours of field assistance in Saint Lucia were also contributed by Bradley
Abraham, Curtis Mathurin, Neil Oculi, Nazza Gustave, Fendley Estephane, Kissinger Henry and Greg Alexander
from Saint Lucia, along with the tireless voluntary efforts of most of the co-authors of Morton et al. (2007) plus Jane
Huston. Catherine Stephen, Bill Toone, Rich Young, Sarah Seymour, Roger Graveson, Melvin Smith, Chris Pilgrim
and most especially Karen Graham all provided much-valued support and insight. The farmers at Sankofa Rainbow
Roots Farm and Roots Farm Zimbabwe, along with the owners of Louvet Estate, the Laule family, kindly facilitated
access to their lands. This part of our work was funded by the Balcombe Trust.
Pictures and measurements of MCZ specimens were kindly provided by Joseph Martinez. We thank two anony-
mous reviewers for their remarks on an earlier version of this manuscript. We thank Catherine Stephen for discus-
sion concerning the status of these iguanas.
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