ArticlePDF Available

A New Nactus Gecko (Gekkonidae) And A New Leiolopisma Skink (Scincidae) From La Réunion, Indian Ocean, Based On Recent Fossil Remains And Ancient Dna Sequence

Authors:

Abstract and Figures

Two new lizards from La Réunion island, southwest Indian Ocean, are described on the basis of fragmentary subfossil material, and their distinctiveness and relationships are confirmed from ancient mitochondrial DNA extracted from these remains. The gecko Nactus soniae n. sp. is related to N. coindemerensis of Mauritius, while the skink Leiolopisma ceciliae n..sp. has affinities with L. telfairii and L. mauritiana from the same island. As with other La Réunion reptiles known to date, mitochondrial DNA phylogenies indicate that both the new forms colonized this island from Mauritius. Molecular clock considerations suggest that colonisations took place over 1My ago and that the new species, together with Phelsuma day geckos, survived the massive volcanic eruptions that took place on La Réunion 180000-230000 years ago.
Content may be subject to copyright.
Accepted by S. Carranza: 28 Dec. 2007; published: 18 Feb. 2008
40
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Copyright © 2008 · Magnolia Press
Zootaxa 1705: 4050 (2008)
www.mapress.com/zootaxa/
A new Nactus gecko (Gekkonidae) and a new Leiolopisma skink (Scincidae)
from La Réunion, Indian Ocean, based on recent fossil remains and
ancient DNA sequence
E. NICHOLAS ARNOLD1 & ROGER BOUR2
1Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK E-mail: ena@nhm.ac.uk
2Reptiles et Amphibiens, Systématique et Évolution, Muséum national d’Histoire naturelle, 75005 Paris, France.
E-mail: bour@mnhn.fr
Abstract
Two new lizards from La Réunion island, southwest Indian Ocean, are described on the basis of fragmentary subfossil
material, and their distinctiveness and relationships are confirmed from ancient mitochondrial DNA extracted from these
remains. The gecko Nactus soniae n. sp. is related to N. coindemerensis of Mauritius, while the skink Leiolopisma cecil-
iae n..sp. .has affinities with L. telfairii and L. mauritiana from the same island. As with other La Réunion reptiles
known to date, mitochondrial DNA phylogenies indicate that both the new forms colonized this island from Mauritius.
Molecular clock considerations suggest that colonisations took place over 1My ago and that the new species, together
with Phelsuma day geckos, survived the massive volcanic eruptions that took place on La Réunion 180000-230000
years ago.
Key words: Nactus, Leiolopisma, La Réunion, ancient DNA, cytochrome b, 12S rRNA
Introduction
La Réunion lies some 500km East of Madagascar and is one of the three Mascarene islands, the others being
Mauritius 200km to the northeast of La Réunion, and Rodrigues 900km to the east. La Réunion was colonised
by people only in the second half of the Seventeenth century (Cheke, 1987), but much of its original verte-
brate fauna of reptiles and birds is now extinct. Just three native reptile species survive: the endemic day gec-
kos, Phelsuma borbonica and P. inexpectata (Austin et al., 2004) and the small lygosomine skink
Cryptoblepharus boutonii. A giant tortoise, Cylindraspis indica (possibly including C. borbonica Bour,
1980—see Austin and Arnold, 2001, Austin et al., 2002) occurred perhaps as late as the mid-1800s (Bour,
1981) and a chalcidine skink, Gongylomorphus bojeri borbonicus became extinct around the same time, hav-
ing last been collected in 1839 (Cheke, 1987). A further skink, similar to the lygosomine Leiolopisma telfairii
of Mauritius, has been recorded from recent fragmentary fossil remains, collected by Graham S. Coles in a
cave near St Paul, on the west coast of La Réunion (Arnold, 1980; Cowles, 1987). Here we report more fossils
that provide further information about this skink and also include a night gecko, Nactus, which again turns out
to be similar to Mauritian species. Mitochondrial DNA sequence recovered from the fossils confirm morpho-
logical indications of the generic allocation of the two forms and confirm that they deserve species status
(Austin and Arnold, 2006, unpublished data).
The new material comes from coastal caves near sea level on the west side of La Réunion. Most is from
the Grotte au Sable, south of the town of St-Gilles, and was excavated by R. Bour and F. Moutou (in 1980),
Zootaxa 1705 © 2008 Magnolia Press · 41
EXTINCT LIZARDS FROM REUNION
and later by C. Mourer-Chauviré and R. Mourer (in 1987). Some Leiolopisma bones were found in the most
northeasterly cave among the Grottes des Premiers Français near St Paul by B. Kervazo (in 1974), and R.
Bour (in 1980). Details of these localities are given by Mourer-Chauviré et al. (1999). Apart from Leiolopisma
and Nactus, material from the Grotte au Sable includes Phelsuma (BMNH R16530-16533; Fig. 1) and Gongy-
lomorphus, and the agamid lizard, Calotes versicolor (Daudin, 1802) (BMNH R16568-16575), a species
introduced from Java in the nineteenth century (A. Vinson, 1871). The Calotes bones are less patinated than
the others, suggesting the latter are significantly older. Finally, a small amount of Leiolopisma material was
excavated from a further cave near St Paul by G. S. Cowles (1987).
Abbreviations
bp base pairs.
BMNH Collections of Natural History Museum, London; specimens with numbers prefixed by ‘R’ are in
the Palaeontology Department of that museum, and the others in the Zoology Department.
Results
Family Gekkonidae
Genus Nactus
Nactus soniae n. sp.
Nactus borbonicus (nomen nudum) in Probst (1997: 144), and in Probst and Brial (2002:24).
Etymology. Named after Sonia Ribes-Beaudemoulin, present curator of the Muséum d’Histoire Naturelle,
Saint-Denis, La Réunion. She organised a dozen expeditions to collect important subfossil remains of verte-
brates, especially tortoises, birds and bats from the marshes of l’Ermitage near St-Gilles.
Distribution. Known only from La Réunion, southwest Indian Ocean.
Material (Figs 2–3). Holotype: Grotte au Sable, St-Gilles, La Réunion; frontal bone; BMNH R16534.
Paratypes: Grotte au Sable, St-Gilles, La Réunion; 1 frontal, 1 maxilla, 1 dentary; BMNH R16535-16537.
DNA sequence. Grotte au Sable, St-Gilles, La Réunion. 681 base pairs (bp) of mitochondrial DNA
sequence extracted from a frontal bone, comprising 305 bp of cytochrome and 374 bp of 12S rRNA genes (J.
J. Austin and E. N. Arnold, unpublished data).
Diagnosis. A small Nactus, estimated from available bones to be about 45mm from snout to vent. Frontal
not elongate, with only weakly developed anterior lateral submaxillary flanges. Maxilla with dorsal lamina
inset medially, so outer surface of tooth-bearing body of bone is rounded; its posterior section comparatively
short. Tooth counts low with 29 teeth in maxilla and 24 in dentary of available material. Also has distinctive
mitochondrial DNA sequence (12S rRNA and cytochrome b).
Differs from other Nactus in conformation of maxilla and from other Mascarene species in the following
additional features: N. serpensinsula and N. durrelli of Mauritius—smaller size and lower tooth counts; N.
coindemerensis of Mauritius—larger size; two undescribed subfossil species from Rodrigues (E. N. Arnold, J.
J. Austin and C. G. Jones, unpublished observations)—lower tooth counts, only weakly developed anterior lat-
eral submaxillary flanges on frontal bone, also lacking the elongation of the frontal found in one of the Rod-
rigues species. Distinguished from sympatric Phelsuma geckos (Fig. 1) by much narrower frontal bone with a
longer tubular section, a higher dorsal lamina on the maxilla and coarser dentition.
ARNOLD & BOUR
42 · Zootaxa 1705 © 2008
Magnolia Press
FIGURE 1. Phelsuma sp., material from Grotte au Sable, St-Gilles, La Réunion. Above: frontals (dorsal and ventral
views). Below: left maxilla (medial view). Scale in mm.
Description. Available material is very fragmentary with only three skull elements represented. Frontal
somewhat expanded anteriorly, and strongly expanded posteriorly, with an intervening narrow waist between
the orbits. The tubular section of the frontal is relatively long and the sides of the expanded posterior section
of the bone are thickened below. Dorsal surface slightly but distinctly concave, with a depressed anterior facet
or facets that would lie under the prefrontals in a complete skull. The shape of the anterior border of the sub-
dermal surface of the frontal, bordering this facet posteriorly is convex anteriorly with a pointed projection on
each side. Small lateral flanges are visible on the frontal anteriorly which would lie under the posterior dorsal
projection of the lamina of each maxilla. The three N. soniae frontals examined (including one sacrificed dur-
ing DNA extraction) show considerable variation in form, including how broad they are, the shape of the ante-
rior border of the dermal surface which is convex and pointed in the holotype but more gently rounded in the
others, and the precise size of the small anterior lateral flanges. The lateral borders of the frontal anterior to its
narrow waist may also be rather wavy.
Maxilla generally similar to other Nactus, especially N. serpensinsula, with a high dorsal lamina that rises
to an acute point posteriorly, where it contacts the frontal, overlapping its anterior lateral flange. A row of four
foramina in a horizontal line on the lateral surface of the tooth-bearing body of the bone and two more where
the body and the dorsal lamina join. Differs from N. serpensinsula and other Nactus in the dorsal lamina being
inset medially on the tooth-bearing body of the maxilla so, in transverse section, the outer face of this is
rounded before the lamina rises. The body of the maxilla posterior to the lamina is relatively short. There are
24 teeth, a similar count to that found in Mauritian N. coindemerensis which has about 26, but considerably
lower than those in N. serpensinsula and N. durrelli which have about 36–38 teeth in adults.
Dentary is similar to that of most other Nactus species, being rather slender, with a short ventral groove at
the anterior extremity; six foramina in a roughly horizontal line on lateral surface which has a tridentate poste-
Zootaxa 1705 © 2008 Magnolia Press · 43
EXTINCT LIZARDS FROM REUNION
rior border, medial surface with a depressed splenial scar and a V-shaped posterior border in which the upper
edge has a pronounced step. The bone, which is from a relatively small individual, has 29 teeth, a count again
similar to that found in Mauritian N. coindemerensis, but considerably lower than those in N. serpensinsula
and N. durrelli which have about 39–40 teeth in adults.
The size of the frontals, the elements apparently from the largest individuals represented in the available
sample, indicate that N. soniae was around 45mm from snout to vent. It is consequently intermediate in size
between N. coindemerensis of Mauritius, which grows to about 36mm from snout to vent, and N. serpensin-
sula and N. durrelli from the same island which reach at least 67mm and 55mm (Arnold and Jones, 1994).
Relationships. DNA confirms that N. soniae is a Nactus and indicates it is most closely related to the
diminutive N. coindemerensis of Mauritius (J. J. Austin and E. N. Arnold, unpublished data), something also
supported by its relatively small size and low tooth counts.
Family Scincidae
Genus Leiolopisma
Leiolopisma ceciliae n. sp.
Etymology. Named after Cécile Mourer-Chauviré, celebrated specialist on fossil birds, who took part in exca-
vations for subfossil remains on La Réunion between 1987 to 2001, identifying half a dozen of new species of
birds. She also proposed the hypothesis of a ‘great extinction’ on the island, associated with cataclysmic vol-
canic eruptions, 180,000–230,000 years ago (Mourer-Chauviré et al., 1999).
Distribution. Known only from La Réunion, southwest Indian Ocean.
Material (Figs 4–6). Holotype: Grotte au Sable, St-Gilles, La Réunion; right dentary; BMNH R16538.
Paratypes: Grotte au Sable, St-Gilles, La Réunion; 1 juvenile frontal, 1 fused postorbital and postfrontal, 2
right maxillae*, 2 quadrates*, 1 left pterygoid, 4 left and 5 right dentaries*, 2 right posterior mandibles*, 6
presacral vertebrae*, 3 left and 3 right humeri*, 1 sacrum, 2 left and 3 right pelves*, 1 left and 1 right fem-
ora*, 1 right tibia; BMNH R16539-16564. Grottes des Premiers Français , St-Paul, La Réunion ; 1 right quad-
rate, 1 right posterior mandible, 1 right humerus; BMNH 16565-16567. Cave near St-Paul, La Réunion; 1
right dentary, 1 partial right humerus, 1 right tibia; BMNH 1977.881-883 (material previously reported and
tibia illustrated by Arnold, 1980).
Most paratype material of Leiolopisma ceciliae is deposited in the reptile collection of the Department of
Palaeontology, Natural History Museum, London. An asterisk indicates that examples of the elements con-
cerned have also been placed in the Muséum d’Histoire Naturelle, St-Denis, La Réunion.
DNA sequence. Grotte au Sable, St-Gilles, La Réunion. 683 bp of mitochondrial DNA sequence extracted
from a left dentary, comprising 307 bp of cytochrome b and 376 bp of 12S rRNA genes (Austin and Arnold,
2006—GenBank accession numbers: AY 818748, AY 818818).
Diagnosis. A Leiolopisma intermediate in adult size and robustness between the two Mauritian species of
the genus, L. telfairii and the giant L. mauritiana. Most similar to L. telfairii but differs in larger maximum
size, coarser dentition, frontal bone narrower anteriorly at least in young animals, the fused postorbital and
postfrontal bones with shorter posterior section and less prominent lateral spur, and quadrate more expanded
lateromedially. L. mauritiana grows much larger than L. ceciliae and has coarser dentition. L. ceciliae is
also separated from L. telfairii and L. mauritiana by distinctive mitochondrial DNA sequence (12S rRNA and
cytochrome b gene fragments).
Fossil remains distinguished from those of the sympatric skink Gongylomorphus bojerii borbonicus by
larger size, fused frontal bones and absence of a Meckel’s groove in the dentary.
ARNOLD & BOUR
44 · Zootaxa 1705 © 2008
Magnolia Press
FIGURE 2a, 2b. Nactus soniae n. sp., material from Grotte au Sable, St-Gilles, La Réunion. a. Holotype. Frontal bone
(dorsal and ventral views). Scale in mm. b. Paratypes. Left maxilla and right dentary (lateral views). Scales in mm.
Zootaxa 1705 © 2008 Magnolia Press · 45
EXTINCT LIZARDS FROM REUNION
FIGURE 2. Nactus soniae n. sp., material from Grotte au Sable, St-Gilles, La Réunion. c. Paratypes. Left maxilla and
right dentary (medial views). Scales in mm.
Description. Available material is fragmentary, but seven cranial and six postcranial elements are repre-
sented. Comparison with material of living L.telfairii indicates a maximum snout-vent length of at least
175mm. Frontal bones fused from an early stage of development as in other lygosomine skinks, narrower
anteriorly than in L. telfairii at least in young animals. Fused postfrontal and postorbital bones with a shorter
posterior section than in L. telfairii and with a less prominent lateral spur that is less obviously directed for-
wards. Dentaries with a closed Meckel’s groove and sometimes more robust than in equivalent sized
L. telfairii from mainland of Mauritius (described by Arnold, 1980), but less so than in L. mauritiana; about
six foramina in a horizontal line on anterior lateral surface. Dentition of maxillae and dentary bones coarser
than in equivalent-sized L. telfairii and finer than in L. mauritiana: this is reflected in differences in tooth
number for animals of similar size (Fig. 7) and in robustness of the teeth. Quadrate more expanded laterome-
dially than in L. telfairii and tibia with a more prominent lower tubercle.
Distinctive features of type. Robust dentary originally with 25 teeth (numbers 2,3,4,9,14 and 22 miss-
ing), the last three teeth decreasing in size; a roughly horizontal line of six foramina present on the anterior lat-
eral surface of the bone.
DNA sequence. DNA of L. ceciliae differs from equivalent regions of the genome of living L. telfairii
from Round island, north of Mauritius, in 39 nucleotide substitutions (5.7% of uncorrected divergence), and
from L. mauritiana by 29 nucleotide substitutions (4.2% uncorrected divergence) – Austin and Arnold (2006).
Relationships. A phylogeny of 42 species of skinks based on mitochondrial DNA associates L. ceciliae
with the other two species of Leiolopisma, corroborating the clade status of this genus (Austin and Arnold,
2006). DNA sequence confirms that Leiolopisma is part of the Lygosominae, something also supported by its
fused frontal bones, and within this subfamily belongs to the Eugongylus group of genera. It also indicates
that, of the two Mauritian species in the genus, L. ceciliae may be more closely related to the giant L. mauriti-
ana, rather than to the morphologically more similar L. telfairii (Austin and Arnold, 2006).
ARNOLD & BOUR
46 · Zootaxa 1705 © 2008
Magnolia Press
FIGURE 3. Nactus soniae n. sp. Scanning electron microscope photograph of holotype frontal bone (dorsal view).
Discussion
Neither Nactus soniae nor Leiolopisma ceciliae is presently known to exist on La Réunion and both are pre-
sumed to be extinct. Nor were they reported during the more than 300 years since human colonization of La
Réunion took place. This is perhaps not surprising in the case of the Nactus which may have been inconspicu-
ous, being small and probably nocturnal like its congeners (Arnold and Jones, 1994). But the large Leiolo-
pisma would surely have attracted comment if it had been seen. Père Brown, a mythical writer for many
historians, whose supposed writings perhaps date from the early Eighteenth century (Cheke, 1987), mentioned
large lizards in the southern part of La Réunion that were claimed to grow to a foot and a half long (a total
length of around 450mm). But Brown also wrote (possibly from secondhand information) that they were arbo-
real, bright and varied in colour, and had a flattened head that was pierced in the middle (perhaps referring to
the way light can pass through one transluscent ear drum of a gekkonid lizard and across the pharynx to be
discernible through the ear drum on the other side). These are all features found in Phelsuma day geckos
Zootaxa 1705 © 2008 Magnolia Press · 47
EXTINCT LIZARDS FROM REUNION
FIGURE 4. Leiolopisma ceciliae n. sp., material from Grotte au Sable, St-Gilles, La Réunion. Holotype. Dentary (lat-
eral and medial views). Scale in mm.
FIGURE 5. Leiolopisma ceciliae n. sp., material from Grotte au Sable, St-Gilles, La Réunion. Selected paratypes, from
individuals of various sizes. Top row: left mandible (lateral view), right maxilla (lateral view), fused left postfrontal and
postorbital bone (dorsal view), left quadrate (posterior view). Middle row: right dentary (medial view), posterior left
mandible (lateral view). Bottom row: Left humerus, left pelvis (lateral view), sacrum (dorsal view), presacral vertebrae
(lateral and ventral views), right femur, tibia. Scale in mm.
rather than skinks, although there is no other evidence that ones of such size occurred on La Réunion. There
were also no eyewitness reports of two species of Leiolopisma on the mainland of Mauritius. It has been sug-
gested in these cases, this was because the skinks had been exterminated by rats from shipwrecks that reached
Mauritius before people actually settled there (Cheke, 1987). This may also have applied to La Réunion,
although the dates rats were first noticed there are relatively well known: about 1670 for the ship rat, Rattus
rattus, and 1750 for the common rat, Rattus norvegicus (Moutou, 1980).
ARNOLD & BOUR
48 · Zootaxa 1705 © 2008
Magnolia Press
FIGURE 6. Leiolopisma ceciliae n. sp., material from Grotte au Sable, St-Gilles, La Réunion. Paratype. Frontal of juve-
nile animal (ventral and dorsal views, anterior upwards). Scale in mm.
With the exception of bolyerine snakes, La Réunion has representatives of all the naturally occurring rep-
tile groups on Mauritius, namely Cylindraspis tortoises, Phelsuma and Nactus geckos, and Leiolopisma and
Gongylomorphus skinks. DNA phylogenies indicate that the giant tortoise (Cylindraspis indica) and the two
day geckos (Phelsuma borbonica and P. inexpectata) reached La Réunion from that island (Austin & Arnold,
2001, Austin et al., 2004), and the same is likely to be true for Leiolopisma ceciliae (Austin & Arnold, 2006)
and Nactus soniae. While Mauritius originally had 19 species and subspecies of reptiles (Arnold, 2000), La
Réunion apparently possessed just seven, in spite of its larger size (2510km2 compared with 1865km2) and its
much more varied geography. This may partly be because groups on Mauritius have all undergone speciation
within the island, while this does not appear to be so for La Réunion. This is a relatively young island, its old-
est rocks being only 2.1My (McDougall, 1971) compared with about 8My for Mauritius (McDougall and
Chamaloun, 1969). However, molecular clocks indicate that the lizards at least have been present on La
Réunion for a long time, at least a million years, in the case of the Phelsuma and perhaps longer for the Leiol-
opisma (Austin et al., 2004, Austin and Arnold, 2006). Like many birds (Mourer-Chauviré et al., 1999), these
forms must have survived the massive eruptions that occurred on the island 180,000–230,000 years ago (Aus-
tin and Arnold, 2004).
Zootaxa 1705 © 2008 Magnolia Press · 49
EXTINCT LIZARDS FROM REUNION
FIGURE 7. Variation in number of teeth with size of maxillae (above) and dentary bones (below) in different species of
the Mascarene skink genus Leiolopisma. Stars: L. ceciliae n. sp. from La Réunion. Assemblage to left: L. telfairii from
Mauritius (triangles: living animals from Round Island, dots: subfossil material from mainland of Mauritius). Assem-
blage to right: subfossil L. mauritiana from mainland of Mauritius. Some symbols indicate more than one specimen.
ARNOLD & BOUR
50 · Zootaxa 1705 © 2008
Magnolia Press
Acknowledgements
We thank G. S. Cowles, B. Kervazo, C. Mourer-Chauviré, F. Moutou and S. Ribes-Beaudemoulin for material
or aid in its collection. J. J. Austin conducted the DNA extractions and analyses mentioned in this paper, N. P.
B. Arnold provided technical help and P. Hurst took the photographs of specimens.
References
Arnold, E.N. (1980) Recently extinct reptile populations from Mauritius and Réunion, Indian Ocean. Journal of Zoology,
London, 191, 33–47.
Arnold, E.N. (2000) Using fossils and phylogenies to understand evolution of reptile communities on islands. Bonner
zoologische Monographien, 46, 309–323.
Arnold, E.N. & Jones, C.J. (1994) The night geckos of the genus Nactus in the Mascarene islands with a description of
the distinctive population on Round island. Dodo, 30, 119–131.
Austin, J.J. & Arnold, E.N. (2001) Ancient mitochondrial DNA and morphology elucidate an extinct island radiation of
Indian Ocean giant tortoises (Cylindraspis). Proceedings of the Royal Society of London B, 268, 2515–2523.
Austin, J.J., Arnold, E.N. & Bour, R. (2002) The provenance of type specimens of extinct Mascarene Island giant tor-
toises (Cylindraspis) revealed by ancient mitochondrial DNA sequences. Journal of Herpetology, 36, 280–285.
Austin, J.J. & Arnold, E.N. (2006) Using ancient and recent DNA to explore relationships of extinct and endangered
Leiolopisma skinks (Reptilia: Scincidae) in the Mascarene islands. Molecular Phylogenetics and Evolution, 39,
503–511.
Austin, J.J., Arnold, E.N. & Jones, C.G. (2004) Reconstructing an island radiation using ancient and recent DNA: the
extinct and living day geckos (Phelsuma) of the Mascarene islands. Molecular Phylogenetics and Evolution, 31,
109–122.
Bour, R. (1981) Histoire de la tortue terrestre de Bourbon. Bulletin de l’Académie de l’Ile de la Réunion. Saint-Denis, 25,
98–147.
Cheke, A.S. (1987) An ecological history of the Mascarene Islands, with particular reference to extinctions and introduc-
tions of land vertebrates. In Diamond, A.W. (ed.) Mascarene Island Birds. Cambridge University Press, Cambridge,
pp. 5–89.
Cowles, G.S. (1987) The fossil record. In Diamond, A. W. (ed.) Mascarene Island Birds. Cambridge University Press,
Cambridge, pp. 90–100.
McDougall, I. (1971) The geochronology and evolution of the young volcanic island of Réunion, Indian Ocean.
Geochimica et Cosmochimica Acta, London, 35, 261–268.
McDougall, I. & Chamaloun, F.H. (1969) Isotopic dating and geomagnetic polarity studies on volcanic rocks from Mau-
ritius, Indian Ocean. Bulletin of the Geological Society of America, 80, 1419–1442.
Mourer-Chauviré, C., Bour, R., Ribes, S. & Moutou, F. (1999) The avifauna of Réunion Island (Mascarene Islands) at the
time of the arrival of the first Europeans. In Olson, S. L. (ed.) Avian paleontology at the close of the 20th century:
Proceedings of the 4th International Meeting of the Society of Avian Paleontology and Evolution, Washington, D. C.,
47 June 1996. Smithsonian Contributions to Paleobiology, 89,1–38.
Moutou, F. (1980) Enquête sur la faune murine dans le département de La Réunion. DDASS, Saint-Denis.
Probst, J.M. (1997) Animaux de La Réunion. Azalées Editions, Sainte-Marie, La Réunion, pp.1–167.
Probst, J.M. & Brial, P. (2002) Récits anciens de naturalistes à l’île Bourbon. Association Nature et Patrimoine, Le Port,
La Réunion, pp.1–112.
Vinson, A. (1871) [Letter dated 1870 to L. Bouton on “Agama versicolor”]. Transactions of the Royal Society of Arts and
Sciences of Mauritius, N. S., 5, 31–34.
... Cylindraspis borbonica Bour, 1978 est un synonyme plus récent de C. indica (voir Austin et al. 2002).  Nactus soniae L'espèce Nactus soniae, le Gecko de Sonia, a été dédiée par Arnold et Bour (2008) à Sonia Ribes-Beaudemoulin, Directrice du Muséum d'Histoire naturelle de Saint-Denis de La Réunion, de 1991 à 2019. Le matériel-type, des pièces osseuses récoltées dans la Grotte au sable à Saint-Gilles, a été déposé au British Museum. ...
... Probst (1996) avait donné un nom à cette espèce, Nactus borbonicus, mais sans la décrire selon les règles du Code international de Nomenclature Zoologique. Ce nom, mentionné encore par Probst (1997b) et Probst & Brial (2002), a été déclaré nomen nudum par Arnold et Bour (2008), tout en le reconnaissant comme un synonyme « plus ancien » de Nactus soniae. ...
... Le Scinque de Cécile, Leiolopisma ceciliae, est connu seulement par des restes fossiles trouvés à La Réunion, dans la Grotte au sable à Saint-Gilles, les grottes des premiers Français à Saint-Paul et une autre grotte, également près de Saint-Paul (Arnold & Bour 2008). L'espèce est dédiée à Cécile Mourer-Chauviré du Muséum d'Histoire naturelle de Lyon (absorbé maintenant dans le Musée des Confluences de cette ville), Liste taxinomique de l'herpétofaune dans l'outre-mer français : VI. ...
Article
Full-text available
Summary-Taxonomic list of the herpetofauna in the Overseas France: VI Department of La Réunion. We present an updated taxonomic checklist of the Amphibians and "Reptiles" of the French department of Reunion Island located in the Mascarene archipelago, southwestern Indian Ocean. We synthesized information from the most recent publications. In addition to the international zoological scientific names, we propose a homogeneous French scientific name for each taxon. Résumé-La liste taxinomique est actualisée et commentée pour les Amphibiens et les « Reptiles » de La Réunion, département et région d'outre-mer, une île de l'archipel des Mascareignes dans l'océan Indien occidental. Elle tient compte des publications les plus récentes. À côté du nom scientifique zoologique international, nous attribuons un nom scientifique zoologique français à chaque taxon.
... Afin de prévenir l'introduction et de la propagation des espèces animales exotiques envahissantes sur le territoire de La Réunion, il est interdit d'introduire dans le milieu naturel tout oeuf ou toute espèce de geckos vivants, à l'exception du Nactus de Sonia (Nactus soniae Arnold & Bour 2008), du gecko vert de Bourbon et du gecko vert de Manapany9. Par ailleurs plusieurs arrêtés préfectoraux ont été pris dans le département 10 , afin de protéger le gecko vert de Bourbon et le gecko vert de Manapany, ainsi que leurs habitats. ...
... Sur la base de ce postulat, la distribution actuelle pourrait être caractérisée de relictuelle, non représentative de l'habitat « naturel » du gecko. R. Bour et al. (1995) suggèrent d'ailleurs que des ossements subfossiles de Phelsuma provenant de la région Ouest (n'ayant jamais été identifiés) (Kervazo, 1979;Arnold & Bour, 2008) pourraient être ceux d'une population de P. inexpectata aujourd'hui éteinte. Seuls des travaux complémentaires (analyses ADN sur le matériel ostéologique subfossile disponible et recherches de nouveaux ossements) permettraient de statuer sur la validité de cette hypothèse. ...
Technical Report
Full-text available
Recovery plan for Phelsuma borbonica and Phelsuma inexpectata
Article
Full-text available
Methodological and technological improvements are continually revolutionizing the field of ancient DNA. Most ancient DNA extraction methods require the partial (or complete) destruction of finite museum specimens, which disproportionately impacts small or fragmentary subfossil remains, and future analyses. We present a minimally destructive ancient DNA extraction method optimized for small vertebrate remains. We applied these methods to detect lost mainland genetic diversity in the large New Zealand diplodactylid gecko genus Hoplodactylus, which is presently restricted to predator‐free island and mainland sanctuaries. We present the first mitochondrial genomes for New Zealand diplodactylid geckos, recovered from 19 modern, six historic/archival (1898 to 2011) and 16 Holocene Hoplodactylus duvaucelii sensu latu specimens, and one modern Woodworthia sp. specimen. No obvious damage was observed in post‐extraction micro‐CT reconstructions. All ‘large gecko’ specimens examined from extinct populations were found to be conspecific with extant Hoplodactylus species, suggesting their large relative size evolved only once in the New Zealand diplodactylid radiation. Phylogenetic analyses of Hoplodactylus samples recovered two genetically (and morphologically) distinct North and South Island clades, probably corresponding to distinct species. Finer phylogeographic structuring within Hoplodactylus spp. highlighted the impacts of Late‐Cenozoic biogeographic barriers, including the opening and closure of Pliocene marine straits, fluctuations in size and suitability of glacial refugia, and eustatic sea‐level change. Recent mainland extinction obscured these signals from the modern tissue derived data. These results highlight the utility of minimally destructive DNA extraction in genomic analyses of less well studied small vertebrate taxa, and the conservation of natural history collections.
Article
Full-text available
Aim The aim was to document the impact of the globalization of human activity on the biodiversity and biogeographical patterns of reptilian and amphibian faunas across islands worldwide. Location Islands worldwide. Time period From the 15th century to the present time. Major taxa studied Reptiles and amphibians. Methods We compiled lists of the reptilian and amphibian species that occurred on islands before the 15th century and of those that occur currently. For each species group, we calculated differences in species richness and in compositional similarities among islands, between the two periods. Regression models were used: (a) to associate the observed differences with spatial patterns of geographical, climatic, biotic and human factors; and (b) to quantify changes in the relative importance of non‐human factors in explaining the spatial patterns of species richness and compositional similarity. Results The richness of reptile and amphibian species increased consistently across islands worldwide. Hotspots of increase were detected in the Caribbean and the Indian Ocean. The composition of species assemblages was substantially homogenized; this was particularly true for amphibians within the Caribbean Sea and for reptiles within the Caribbean Sea and Indian Ocean and between the Indian and the Pacific Oceans. Our results showed that spatial patterns of change in species richness and compositional similarity are driven by human and natural factors. The driving role of mean annual temperature is particularly consistent, and current reptile richness and compositional similarity patterns for both species groups are increasingly being shaped by the global temperature gradient. Main conclusions The globalization of human activity is eroding the regionalized character of insular herpetofaunas and leading to the emergence of global‐scale gradients of taxonomic composition and species richness. Projections of increasing rates of biological invasions, extinctions and climate change suggest that these changes are likely to be aggravated even further in the coming decades.
Article
Models for biodiversity growth on the remote oceanic islands assume that in situ cladogenesis is a major contributor. To test this, we compiled occurrence data for 194 terrestrial reptile species on 53 volcanically-constructed middle-to low-latitude landmasses worldwide. Despite 273 native island-species records, there are only 8-12 cases of the phenomenon, including just two radiations. Diversification frequencies are largely uncorrelated with island area, age, maximum altitude, and isolation. Furthermore, there is no indication that the presence of non-sister congeners on an island stymies the process. Diversity on individual oceanic islands therefore results primarily from immigration and anageneis, but this is not a simple matter. Clusters that are difficult to reach (far or challenging to get to) or thrive upon (e.g. Canaries, Galápagos) have relatively few clades (3-8), some of which have many species (6-14), and all host at least one endemic genus. In these settings, diversity grows mainly by intra-archipelago transfer followed by within-island anagenetic speciation. In contrast, those island groups that are easier to disperse to (characterized by short distances and conducive transit conditions) and harbour more benign habitats (e.g. Comoros, Lesser Antilles) have been settled by many ancestor-colonizers (≥ 14), but each clade has few derived species (≤ 4). These archipelagoes lack especially distinctive lineages. Models explaining the assembly and growth of terrestrial biotic suites on the volcanic ocean islands thus need to accommodate these new insights.
Article
Models for biodiversity growth on the remote oceanic islands assume that in situ cladogenesis is a major contributor. To test this, we compiled occurrence data for 194 terrestrial reptile species on 53 volcanically-constructed middle- to low-latitude landmasses worldwide. Despite 273 native island-species records, there are only 8–12 cases of the phenomenon, including just two radiations. Diversification frequencies are largely uncorrelated with island area, age, maximum altitude, and isolation. Furthermore, there is no indication that the presence of non-sister congeners on an island stymies the process. Diversity on individual oceanic islands therefore results primarily from immigration and anageneis, but this is not a simple matter. Clusters that are difficult to reach (far or challenging to get to) or thrive upon (e.g. Canaries, Galápagos) have relatively few clades (3–8), some of which have many species (6–14), and all host at least one endemic genus. In these settings, diversity grows mainly by intra-archipelago transfer followed by within-island anagenetic speciation. In contrast, those island groups that are easier to disperse to (characterized by short distances and conducive transit conditions) and harbour more benign habitats (e.g. Comoros, Lesser Antilles) have been settled by many ancestor-colonizers (≥ 14), but each clade has few derived species (≤ 4). These archipelagoes lack especially distinctive lineages. Models explaining the assembly and growth of terrestrial biotic suites on the volcanic ocean islands thus need to accommodate these new insights.
Article
Full-text available
Models for biodiversity growth on the remote oceanic islands assume that in situ cladogenesis is a major contributor. To test this, we compiled occurrence data for 194 terrestrial reptile species on 53 volcanically‐constructed middle‐ to low‐latitude landmasses worldwide. Despite 273 native island‐species records, there are only 8–12 cases of the phenomenon, including just two radiations. Diversification frequencies are largely uncorrelated with island area, age, maximum altitude, and isolation. Furthermore, there is no indication that the presence of non‐sister congeners on an island stymies the process. Diversity on individual oceanic islands therefore results primarily from immigration and anageneis, but this is not a simple matter. Clusters that are difficult to reach (far or challenging to get) to or thrive upon (e.g. Canaries, Galápagos) have relatively few clades (3–8), some of which have many species (6–14), and all host at least one endemic genus. In these settings, diversity grows mainly by intra‐archipelago transfer followed by within‐island anagenetic speciation. In contrast, those island groups that are easier to disperse to (characterized by short distances and conducive transit conditions) and benign habitats (e.g. Comoros, Lesser Antilles) have been settled by many ancestor‐colonizers (≥14), but each clade has few derived species (≤4). These archipelagoes lack especially distinctive lineages. Models explaining the assembly and growth of terrestrial biotic suites on the volcanic ocean islands thus need to accommodate these new insights. This article is protected by copyright. All rights reserved.
Article
Full-text available
Global change and human expansion have resulted in many species extinctions worldwide, but the geographic variation and determinants of extinction risk in particular guilds still remain little explored. Here, we quantified insular extinctions of frugivorous vertebrates (including birds, mammals and reptiles) across 74 tropical and subtropical oceanic islands within 20 archipelagos worldwide and investigated extinction in relation to island characteristics (island area, isolation, elevation and climate) and species’ functional traits (body mass, diet and ability to fly). Out of the 74 islands, 33 islands (45%) have records of frugivore extinctions, with one third (mean: 34%, range: 2–100%) of the pre-extinction frugivore community being lost. Geographic areas with more than 50% loss of pre-extinction species richness include islands in the Pacific (within Hawaii, Cook Islands and Tonga Islands) and the Indian Ocean (Mascarenes, Seychelles). The proportion of species richness lost from original pre-extinction communities is highest on small and isolated islands, increases with island elevation, but is unrelated to temperature or precipitation. Large and flightless species had higher extinction probability than small or volant species. Across islands with extinction events, a pronounced downsizing of the frugivore community is observed, with a strong extinction-driven reduction of mean body mass (mean: 37%, range: -18–100%) and maximum body mass (mean: 51%, range: 0–100%). The results document a substantial trophic downgrading of frugivore communities on oceanic islands worldwide, with a non-random pattern in relation to geography, island characteristics and species’ functional traits. This implies severe consequences for ecosystem processes that depend on mutualistic plant-animal interactions, including ecosystem dynamics that result from the dispersal of large-seeded plants by large-bodied frugivores. We suggest that targeted conservation and rewilding efforts on islands are needed to halt the defaunation of large and non-volant seed dispersers and to restore frugivore communities and key ecological interactions.
Article
Full-text available
Ancient mitochondrial DNA sequences were used for investigating the evolution of an entire clade of extinct vertebrates, the endemic tortoises (Cylindraspis) of the Mascarene Islands in the Indian Ocean. Mitochondrial DNA corroborates morphological evidence that there were five species of tortoise with the following relationships: Cylindraspis triserrata ((Cylindraspis vosmaeri and Cylindraspis peltastes) (Cylindraspis inepta and Cylindraspis indica)). Phylogeny indicates that the ancestor of the group first colonized Mauritius where speciation produced C. triserrata and the ancestor of the other species including a second sympatric Mauritian form, C. inepta. A propagule derived from this lineage colonized Rodrigues 590 km to the east, where a second within-island speciation took place producing the sympatric C. vosmaeri and C. peltastes. A recent colonization of Réunion 150 km to the southwest produced C. indica. In the virtual absence of predators, the defensive features of the shells of Mascarene tortoises were largely dismantled, apparently in two stages. 'Saddlebacked' shells with high fronts evolved independently on all three islands. This and other features, such as a derived jaw structure and small body size, may be associated with niche differentiation in sympatric species and may represent a striking example of parallel differentiation in a large terrestrial vertebrate. The history of Mascarene tortoises contrasts with that of the Galápagos, where only a single species is present and surviving populations are genetically much more similar. However, they too show some reduction in anti-predator mechanisms and multiple development of populations with saddlebacked shells.
Chapter
First published in 1987, this volume presents the scientific results of an expedition, promoted by the British Ornithologists' Union, to study the endangered birds of the Mascarene Islands in the Indian Ocean. This group of islands is of unique importance to bird conservation and is perhaps best known as the last home of the famous dodo. Thirty endemic species of birds are already extinct and the populations of several others are now so small as to be of doubtful validity. The data presented here will enable the appropriate government departments and conservation bodies to proceed on the basis of a sound knowledge of the needs of the threatened birds, and it is hoped that the survival of at least a proportion of the unique wildlife of this island group can be ensured. Studies of Mascarene Island Birds will also provide the keen amateur ornithologist with a serious interest in conservation with a direct appreciation of field work aimed at protecting rate species in their natural habitat.
Article
Results of a geochronological and paleomagnetic investigation of the volcanic island of Mauritius are reported. Potassium-argon dates indicate that the main shield volcano was built subaerially between about 7.8 and 6.8 m.y. ago in the early Pliocene. Some evidence is presented for caldera formation following the construction of the volcanic shield. Profound erosion subsequently destroyed much of the volcano, leaving only peripheral steep-sided massifs. Lavas of the Younger Volcanic Series were erupted from about 3.5 m.y. ago until less than 0.2 m.y. ago, flooding the denuded stumps of the shield volcano. This activity was intermittent and a hiatus is recognized from about 2 to 0.7 m.y. ago, which we have taken as the break between the eruption of the Early and Late Lavas of the Younger Volcanic Series. The mean directions of magnetization of the three groups of lavas are not significantly different from one another and are close to an axial dipole direction. The combined paleomagnetic and dating studies on the lavas also yield further information on the geomagnetic polarity time scale; 16 results on rocks with ages lying between 3.5 and 0.17 m.y. are consistent with the established scale for this period of geological time. Of particular significance are results that confirm the Mammoth reversed event at 3.0 m.y. ago, and the age of the boundary between the Gauss normal and Gilbert reversed polarity epochs at 3.35 m.y. Nineteen results were obtained on rocks whose ages are between 4.6 and 7.9 m.y., and these data generally are consistent with the polarity time scale based upon extrapolations from the sea-floor spreading hypothesis. The evolution of the Mascarene Islands, comprising Mauritius, Réunion and Rodriguez is briefly reviewed and it is concluded that each island had developed independently, and that no correlation of age with respect to distance from the Mid-Indian Ocean Ridge is observed. The volcanism that has built Mauritius and Réunion may be a continuation of the development of the Mascarene Plateau with migration of the activity generally southward with time.
Article
Previously unreported material of recently extinct reptiles from Mauritius and Reunion is discussed. It confirms the original presence on Mauritius of three species now largely or entirely confined to nearby Round Island: the gecko Cyrtodactylus serpensinsula, the skink, Leiolopisma telfairii and the boa, Casarea dussumieri. Leiolopisma telfairii is also recorded from Reunion for the first time. Leiolopisma telfairii and the extinct giant Dido–saurus mauritianus are shown to be very similar to each other and quite probably derivatives of a single invading species. D. mauritianus is consequently transferred to Leiolopisma. Apparently pathological tooth structure in this form is also reported.
Article
A detailed K-Ar study of subaerial lavas from Réunion, using whole rock samples, shows that the measured ages are fully consistent with the excellent stratigraphic control available. The amount of extraneous radiogenic argon present in three of the groups of basalt flows is about 1 ± 1 × 10−13 mol/g, and for many of the younger lavas the content must be less than 3 × 10−13 mol/g. However, extraneous argon has been detected in alkali feldspar and amphibole in hypabyssal drusy syenites that are exposed in the eroded core of Piton des Neiges volcano.The ages enable part of the history of the two volcanoes comprising Réunion to be elucidated. The subaerial basaltic shield building lavas of Piton des Neiges were erupted during at least three distinct episodes at about 2 m.y., 1.2-1.0 m.y. and 0.55-0.43 m.y. ago. Following a hiatus of about 0.1 m.y. a sequence of alkali andesites and basalts was erupted between about 0.35 and 0.07 m.y. ago. The younger, and still active volcano, Piton de la Fournaise, which is built entirely of basaltic lavas, was active from at least 0.36 m.y. ago. The focus of basaltic eruption has migrated progressively toward the southeast with time, and may indicate that Réunion has moved toward the northwest, away from the southwest branch of the mid-Indian Ocean ridge, across the source region for the magmas in the upper mantle.
Article
Phylogenetic analysis, using 1455 bp of recent mtDNA (cytochrome b 714 bp, 12S rRNA 376 bp) and nuclear (c-mos 365 bp) sequence from 42 species and 33 genera of Scincidae, confirms Leiolopisma telfairii, now confined to Round island off Mauritius, is a member of the mainly Australasian Eugongylus group of the Lygosominae. Ancient mtDNA (cytochrome b 307 bp, 12S rRNA 376 bp) was also extracted from subfossils of two other Mascarene taxa that are now extinct: the giant L. mauritiana from Mauritius and Leiolopisma sp., known only from fragmentary remains from Réunion. Sequence divergences of 4.2-5.7% show that all three forms were distinct and form a clade. There is restricted evidence that L. mauritiana and L. sp. from Réunion were sister species. Monophyly and relationships suggest Leiolopisma arose from a single transmarine invasion of the oceanic Mascarene islands from Australasia, 5600-7000 km away. This origin is similar to that of Cryptoblepharus skinks and Nactus geckos in the archipelago but contrasts with Phelsuma day geckos, which appear to have arrived from Madagascar where Mascarene Cylindraspis tortoises may also have originated. Diversification of the known species of Leiolopisma occurred from about 2.3-3.4 Mya, probably beginning on Mauritius with later invasion of Réunion. The initial coloniser may have had a relatively large body-size, but L. mauritiana is likely to have become gigantic within the Mascarenes. Other relationships supported by this investigation include the following. Scincines: Pamelaescincus+Janetaescincus, and Androngo (Amphiglossus, Paracontias). Lygosomines: Sphenomorphus group--(Sphenomorphus, Lipinia (Ctenotus, Anomalopus (Eulamprus and Gnypetoscincus))): Egernia group--Egernia (Cyclodomorphus, Tiliqua); Eugongylus group--(Oligosoma, Bassiana. (Lampropholis (Niveoscincus, Carlia))).