A SURVEY OF BLOOD PARASITES OF BIRDS IN THE MASCARENE ISLANDS, INDIAN OCEAN: WITH DESCRIPTIONS OF TWO NEW SPECIES AND TAXONOMIC DISCUSSION

A survey was carried out on the prevalence of blood parasites in birds in the Mascarene Islands. Smears from 357 birds of 25 species in 12 families were examined, of which 150 (42%) were found to harbour blood parasites. The most common parasites were Leucocytozoon ; a new species, L. zosteropis , is described from the Grey White-eye Zosterops borbonica mauritiana. This parasite was observed in smears from 68 birds of three species: Z. borbonica, Z. chloronothos and Z. olivacea. Other species of Leucocytozoon identified were L. fringillinarum from fodies, sparrows and a bulbul and L. marchouxi from two doves.
Haemoproteus was found only in domestic pigeons Columba livia and identified as H. columbae. Plasmodium relictum, P. vaughani and an unidentified species with elongate gametocytes were found in Zosterops , and Plasmodium sp. of low infection observed in other hosts. Trypanosoma mayae is redescribed from the House Sparrow Passer domesticus and the Mauritius Fody Foudia rubra , and considered to be a valid species. A new species of trypanosome, Trypanosoma phedinae , is described from the Malagasy Swallow Phedina b. borbonica. Other birds were found to harbour low infections of unidentified species of trypanosomes. A small number of birds were infected with Atoxoplasma , haemogregarines and Rickettsia-like organisms. An unidentified organism with a predilection for eosinophils was observed in several Mascarene Swiftlets Collocalia francica.
The results are discussed in relation to the possible effects of the parasites on the birds of the Mascarene Islands and comparisons made with the results of similar surveys on other Indian Ocean Islands.     

A new genus of taeniapterine Micropezidae (Diptera) from the Mascarene Islands

Abstract. Courtoisia , a new genus of rarely encountered taeniapterine Micropezidae (Diptera), is described from the Mascarene Islands of Réunion and Mauritius. The affinities of Courtoisia with other Old World genera of Taeniap-terinae, most notably those from the Afrotropical Region, are discussed. A possible derivation of Courtoisia from ancestral stock of the African genus Cephalosphen Hennig, 1934 is suggested. A tentative theory to explain the dispersal of a founder population from Africa to the Mascarene Islands is discussed. Courtoisia was erected to accommodate Calobata apicalis and C.trinotata , both described from Réunion by Macquart in 1851. Both species are redescribed on the basis of all available material and a lectotype is designated for Calobata trinotata. A key to the species of Courtoisia is presented.     

Phylogenetic relationships based on morphology among the Diospyros (Ebenaceae) species endemic to the Mascarene Islands

The Diospyros (Ebenaceae) species which colonized the Mascarene Islands, namely Mauritius, Reunion and Rodrigues, have been decimated over the years by human settlements. Of the 14 endemic species that have been described and collected for herbaria, Diospyros angulata is now believed to be extinct in Mauritius. The phylogenetic relationships of the 14 Diospyros species were determined using maximum parsimony analysis of 35 morphological characters. This analysis separated the Mascarene Diospyros into two major clades, with D. revaughanii , D. egrettarum and D. leucomelas grouped in the same strongly supported most basal clade while the rest of the species formed the other major clade. High bootstrap values were obtained for the sister species D. angulata and D. boutonania , and the clade clustering the upland species D. neraudii , D. nodosa and D. pterocalyx . There was also relatively strong support for the clade comprising D. hemiteles and D. melanida , which are located in mid altitude regions. These results indicate that Diospyros species most probably colonized the coastal areas of Mauritius and then moved to mid altitude habitats before finally reaching the upland regions. There are also strong indications that D. borbonica and D. diversifolia , endemic to Reunion and Rodrigues, respectively, resulted from migrations from Mauritius.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 307–313.     

Variation among strains of Xanthomonas campestris pv. vasculorum from Mauritius and other countries based on fatty acid analysis

Fatty acid profiling was used to study variation amongst strains of Xanthomonas campestris pv. vasculorum (Xcv). They could be divided into five groups using cellular fatty acid profiles. Group A strains represent a new and little known taxon and all came from plants of broom bamboo (Thysanolaena maxima) from Mauritius. Group B strains included the Xcv pathotype reference strain and were from palms, broom bamboo and sugarcane from Mauritius, Reunion and Australia. Group C contained southern African and Malagasy strains from sugarcane and maize, together with X. campestris pv. holcicola strain. No Mascarene strains fell into this group. Group D strains isolated from sugarcane, maize and royal palm (Roystonea regia) were from Mauritius and Reunion, the earliest known strains coming from Réunion. These groups represented in the Mascarene Islands possibly belong to three different Xanthomonas species. A further Group E comprised one Xcv strain (NCPPB 182) from Puerto Rico, one X. vasicola pv. holcicola strain plus 6 other unclassified Xanthomonas strains causing red stripe disease symptoms in sugarcane. Three of these groups occur on Mauritius and two occur on Réunion. Group B strains originally caused serious problems in noble canes. As resistant interspecific hybrids were introduced, group D strains appeared in Mauritius possibly being introduced from Reunion but having similar host ranges within the Gramineae and Palmae. The findings that 3 of these groups (A, B, D) can cause gumming disease in a grass species (T. maxima) and that 2 of them (B, D) also cause gumming disease in sugar cane (Gramineae) and palms (Palmae) is unusual.     

Molecular biology,phytochemistry and bioactivity of three endemic Aloe species from Mauritius and Réunion Islands

Introduction – Aloe tormentorii, A. purpurea and A. macra are used as multipurpose folk medicines in Réunion and Mauritius Islands and are mistaken for the introduced Aloe vera. Objective – To compare the phytochemical, antimicrobial and DNA profiles of Aloe endemic to Mauritius and Réunion with the profiles of A. vera. Methodology – Leaf extracts of these Aloe species were analysed using standard phytochemical screening techniques, TLC and by HPLC. These extracts were also assayed for antimicrobial activity using microdilution techniques. Genetic diversity was studied using RAPD markers. Results – Phytochemical and antimicrobial assays and RAPD analysis showed that Mascarene Aloe species were very different from A. vera. Conclusion – This study is the first report highlighting the differences between Aloe sp.p from Mascarene and Aloe vera at the metabolic and genomic level. Copyright © 2010 John Wiley & Sons, Ltd.     

Geographic origin and taxonomic status of the invasive Privet, Ligustrum robustum (Oleaceae), in the Mascarene Islands, determined by chloroplast DNA and RAPDs

Information concerning the area of origin, genetic diversity and possible acquisition of germplasm through hybridisation is fundamental to understanding the evolution, ecology and possible control measures for an introduced invasive plant species. Among the most damaging of alien plants that are invading and degrading native vegetation in the Mascarene Islands of the Indian Ocean is the Tree Privet, Ligustrum robustum. Exact information about the geographic source of introduced material of this species is lacking, in part because Ligustrum is a taxonomically difficult genus. Native material of L. robustum ssp. walkeri from Sri Lanka, L. robustum ssp. robustum from northeastern India, and the closely related L. perrottetii from southern India was compared with introduced material from La Réunion and Mauritius using chloroplast DNA RFLP markers and random amplified polymorphic DNA (RAPDs). Sri Lankan and introduced material was monomorphic for the same cpDNA haplotype that was absent from south and northeast Indian Ligustrum. Sri Lankan and introduced material was also clearly distinguished from Indian Ligustrum by RAPDs. It was concluded that material introduced and established in the Mascarene Islands is derived from the Sri Lankan subspecies L. robustum ssp. walkeri. No geographic structuring of genetic variation within Sri Lanka was detected for this taxon, so the location(s) within Sri Lanka from which introduced material is derived could not be pinpointed. RAPDs indicate that L. robustum ssp. walkeri in Sri Lanka is more similar to south Indian L. perrottetii than to northeast Indian L. robustum ssp. robustum. Moreover, RAPDs showed that introduced material in La Réunion has undergone little or no loss of genetic diversity since introduction. However, there was no evidence that it is introgressed with germplasm from two other alien Ligustrum species present on La Réunion.     

Ancient mitochondrial DNA and morphology elucidate an extinct island radiation of Indian Ocean giant tortoises (Cylindraspis).

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.     

Selaginella bifida sp. nov. (Selaginellaceae: Pteridophyta) from Rodrigues Island, Mauritius

Selaginella bifida D. Delmail, a new species of the Selaginellaceae from Rodrigues Island, (Mascarene archipelago, Mauritius) is described and illustrated. The new species is related to S. rodrigueziana Baker in phenotypic appearance, but differs by having ciliate lateral leaf margins and bifid microsporophyll apices.     

Biogeography and diversification of hermit spiders on Indian Ocean islands (Nephilidae: Nephilengys)

The origin of the terrestrial biota of Madagascar and, especially, the smaller island chains of the western Indian Ocean is relatively poorly understood. Madagascar represents a mixture of Gondwanan vicariant lineages and more recent colonizers arriving via Cenozoic dispersal, mostly from Africa. Dispersal must explain the biota of the smaller islands such as the Comoros and the chain of Mascarene islands, but relatively few studies have pinpointed the source of colonizers, which may include mainland Africa, Asia, Australasia, and Madagascar. The pantropical hermit spiders (genus Nephilengys) seem to have colonized the Indian Ocean island arc stretching from Comoros through Madagascar and onto Mascarenes, and thus offer one opportunity to reveal biogeographical patterns in the Indian Ocean. We test alternative hypotheses on the colonization route of Nephilengys spiders in the Indian Ocean and simultaneously test the current taxonomical hypothesis using genetic and morphological data. We used mitochondrial (COI) and nuclear (ITS2) markers to examine Nephilengys phylogenetic structure with samples from Africa, southeast Asia, and the Indian Ocean islands of Madagascar, Mayotte, Réunion and Mauritius. We used Bayesian and parsimony methods to reconstruct phylogenies and haplotype networks, and calculated genetic distances and fixation indices. Our results suggest an African origin of Madagascar Nephilengys via Cenozoic dispersal, and subsequent colonization of the Mascarene islands from Madagascar. We find strong evidence of gene flow across Madagascar and through the neighboring islands north of it, while phylogenetic trees, haplotype networks, and fixation indices all reveal genetically isolated and divergent lineages on Mauritius and Réunion, consistent with female color morphs. These results, and the discovery of the first males from Réunion and Mauritius, in turn falsify the existing taxonomic hypothesis of a single widespread species, Nephilengys borbonica, throughout the archipelago. Instead, we diagnose three Nephilengys species: Nephilengys livida (Vinson, 1863) from Madagascar and Comoros, N. borbonica (Vinson, 1863) from Réunion, and Nephilengys dodo new species from Mauritius. Nephilengys followed a colonization route to Madagascar from Africa, and on through to the Mascarenes, where it speciated on isolated islands. The related golden orb-weaving spiders, genus Nephila, have followed the same colonization route, but Nephila shows shallower divergencies, implying recent colonization, or a moderate level of gene flow across the archipelago preventing speciation. Unlike their synanthropic congeners, N. borbonica and N. dodo are confined to pristine island forests and their discovery calls for evaluation of their conservation status.     

Herbivore-deterring secondary compounds in heterophyllous woody species of the Mascarene Islands

Heterophylly (juvenile-adult leaf dimorphism) is widespread among native woody species of the Mascarene Islands, but the causes to this phenomenon have so far not been fully explained. The absence of mammals and dominance of now extinct giant tortoises and flightless birds are characteristics of the original Mascarene fauna. The present study investigates the hypothesis that the distinct morphology and colouration of juvenile leaves signalled unpalatability to browsing giant tortoises or birds. Juvenile and adult leaves of 28 heterophyllous woody species endemic to the islands of Mauritius and Rodrigues were screened for possible chemical defences against herbivory. The screening comprised the following classes of secondary compounds: alkaloids, cyanogenic constituents, saponins, simple phenolics, tannins and anthocyanins. The screening showed that there are no consistent significant differences between juvenile and adult leaves regarding any of the studied secondary compound classes, with the exception of the level of anthocyanins, which was significantly higher in juvenile leaves. This difference was also clearly reflected in a generally high degree of red patterning of juvenile leaves. Based on comparisons with floras of other oceanic islands once inhabited by tortoises and birds, and an evaluation of feeding habits of these herbivores, we suggest that the reduced lamina and partly red colouration of juvenile leaves may be an evolutionary response to selective herbivory by birds.     

Using ancient and recent DNA to explore relationships of extinct and endangered Leiolopisma skinks (Reptilia: Scincidae) in the Mascarene islands

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))).     

The Use of Extant Non-Indigenous Tortoises as a Restoration Tool to Replace Extinct Ecosystem Engineers

We argue that the introduction of non-native extant tortoises as ecological replacements for extinct giant tortoises is a realistic restoration management scheme, which is easy to implement. We discuss how the recent extinctions of endemic giant Cylindraspis tortoises on the Mascarene Islands have left a legacy of ecosystem dysfunction threatening the remnants of native biota, focusing on the island of Mauritius because this is where most has been inferred about plant–tortoise interactions. There is a pressing need to restore and preserve several Mauritian habitats and plant communities that suffer from ecosystem dysfunction. We discuss ongoing restoration efforts on the Mauritian offshore Round Island, which provide a case study highlighting how tortoise substitutes are being used in an experimental and hypothesis-driven conservation and restoration project. The immediate conservation concern was to prevent the extinction and further degradation of Round Island's threatened flora and fauna. In the long term, the introduction of tortoises to Round Island will lead to valuable management and restoration insights for subsequent larger-scale mainland restoration projects. This case study further highlights the feasibility, versatility and low-risk nature of using tortoises in restoration programs, with particular reference to their introduction to island ecosystems. Overall, the use of extant tortoises as replacements for extinct ones is a good example of how conservation and restoration biology concepts applied at a smaller scale can be microcosms for more grandiose schemes and addresses more immediate conservation priorities than large-scale ecosystem rewilding projects.     

Pinnipeds or sirenians at western Indian Ocean Islands?

Records of pinnipeds and sirenians are rare in the western Indian Ocean away from continental coasts. In the case of pinnipeds there are apparently no records at all in this area, except for occasional stray Elephant seals Mirounga leonina as far north as Mauritius and Rodriguez, and a single record of an undetermined species in the southern Maldive Islands: the Indian Ocean now lacks any counterpart of the Monk seals of the Caribbean and the Pacific (King, 1956, 1964). In the case of sirenians, Dugongs are widely distributed round the continental coasts of the Indian Ocean, including Madagascar, the Comoros, and Ceylon, but there is much less information concerning them on more remote Indian Ocean islands. This paper draws attention to hitherto unnoticed reports of animals which could be either pinnipeds or sirenians made by 18th and early 19th century navigators, and reviews some of the published evidence for the existence of these animals in the 17th and 18th centuries in the Mascarene Islands. It is shown that many of the reef islands of the tropical western Indian Ocean were formerly inhabited by seals, of undetermined species and now extinct, and that some of the early references to Dugongs in fact concerned seals.     

A genetic diversity study of endangered Psiadia species endemic from Mauritius Island using PCR markers

The genus Psiadia Jacq. represents the most important indigenous genus, by the number of species present, in the Mascarene archipelago (Mauritius, Reunion, Rodrigues), and is a typical example of adaptive radiation in oceanic islands. The Mauritius species are used in traditional pharmacopoeia for their expectorant properties, and most of them are heavily threatened. Molecular genetic relationships between representatives of eight endangered endemic Psiadia species from Mauritius, conserved in Le Mondrain Reserve, and P. dentata (Cass.) DC, endemic from Reunion island, were studied. The absence of length variations of the 5s rDNA non-transcribed spacer demonstrated the recent common origin of all the species surveyed. RAPD analysis revealed a relatively high intra-specific variability in accordance with the outcrossing mode of reproduction of Psiadia species. Moreover, RAPD analysis showed the existence of four major phenetic groups: (A) P. arguta (Pers.) Voigt, P. dentata, (B) P. penninervia D. C., P. terebinthina A.J. Scott, P. lithospermifolia (Lam.) Cordem, (C) P. viscosa (Lam.) A.J. Scott, P. canescens A.J. Scott, P. cataractae A.J. Scott, and (D) P. pollicina A.J. Scott. These groups were consistent with the chemical composition of the essential oils of the species as well as with their floral characteristics, based on literature. A molecular germplasm database for Psiadia species was established, which will allow further characterisation of new samples being introduced in Le Mondrain Reserve for conservation purpose.     

A revision of <Emphasis Type="Italic">Foetidia</Emphasis> (Lecythidaceae subfamily Foetidioideae)

Seventeen species of Foetidia are recognized; one from East Africa, two from the Mascarene Islands and the remaining fourteen from Madagascar. A key to all the species is provided for the first time.     

Tristyly in the endangered Mascarene Island endemic Hugonia serrata (Linaceae)

Tristyly is a rare floral polymorphism known to occur in only five flowering plant families. One unresolved and potential additional case of tristyly concerns the genus Hugonia in the Linaceae. Here we confirm the existence of tristyly in the genus by reporting floral measurements made on Hugonia serrata Lam., an extremely rare species endemic to the Mascarene Islands of La Réunion and Mauritius in the southern Indian Ocean. We conducted an extensive search of all natural habitats on La Réunion Island where the species had been previously reported. Twenty-eight individuals were found, of which nine were in flower. Of the nine flowering individuals five had long-styled flowers with the stigmas placed above the two levels of anthers, three had intermediate length styles with the stigmas placed between the two anther levels, and one had stigmas placed below the two anther levels, i.e., three floral morphs could be identified based on the sequence of stigma and anther positions. Reciprocity and precision indices calculated for sexual organ length in each morph confirm that this variation is well within the range of values observed by previous workers on other tristylous species in other families. Our empirical data confirm the existence of tristyly in the genus Hugonia, thereby raising the number of known families in which tristyly occurs to six. Pollen size, pollen number, and anther length increased slightly with stamen length, but the low number of plants precludes statistical tests of these trends. A bibliographic survey suggests that tristyly may occur in several other species of the genus.     

Predicting seasonal movements and distribution of the sperm whale using machine learning algorithms

Implementation of effective conservation planning relies on a robust understanding of the spatiotemporal distribution of the target species. In the marine realm, this is even more challenging for species rarely seen at the sea surface due to their extreme diving behavior like the sperm whales. Our study aims at (a) investigating the seasonal movements, (b) predicting the potential distribution, and (c) assessing the diel vertical behavior of this species in the Mascarene Archipelago in the south‐west Indian Ocean. Using 21 satellite tracks of sperm whales and eight environmental predictors, 14 supervised machine learning algorithms were tested and compared to predict the whales'' potential distribution during the wet and dry season, separately. Fourteen of the whales remained in close proximity to Mauritius, while a migratory pattern was evidenced with a synchronized departure for eight females that headed towards Rodrigues Island. The best performing algorithm was the random forest, showing a strong affinity of the whales for sea surface height during the wet season and for bottom temperature during the dry season. A more dispersed distribution was predicted during the wet season, whereas a more restricted distribution to Mauritius and Reunion waters was found during the dry season, probably related to the breeding period. A diel pattern was observed in the diving behavior, likely following the vertical migration of squids. The results of our study fill a knowledge gap regarding seasonal movements and habitat affinities of this vulnerable species, for which a regional IUCN assessment is still missing in the Indian Ocean. Our findings also confirm the great potential of machine learning algorithms in conservation planning and provide highly reproductible tools to support dynamic ocean management.     

An Assessment of Habitat Diversity and Transformation on La Réunion Island (Mascarene Islands,Indian Ocean) as a Basis for Identifying Broad-scale Conservation Priorities

Most natural habitat in the Mascarene Islands (Mauritius, La Réunion and Rodrigues) has been transformed. Although urbanisation, agriculture and alien plant invasions have transformed large areas in La Réunion, the island has by far the greatest area of intact habitats in the Mascarenes, but remaining natural areas are under threat. We propose a protocol for defining a system of habitat types and for using these to provide a preliminary assessment of conservation priorities for La Réunion. The protocol draws on existing data and expert knowledge to map habitat types, assesses the extent of habitat transformation, and quantifies heterogeneity between habitat types based on climate, topography and geology. The pattern of habitat transformation was uneven among the nineteen habitat types identified. While three habitats have lost > 95% of their original area, four still retain> 80% of their original extent. Habitat types could be grouped into the following categories: (i) transformed habitats with low levels of plant endemism, (ii) habitats confined to homogenous geology with high levels of plantendemism, and (iii) species-rich heterogeneous habitats on diverse geological types. Priority habitats were also identified using municipalities as a basis for implementation. Urgent action is required for several habitat types where a large part of the original extent has been transformed. Three municipalities which contain more than 10 habitat types should receive conservation priority. The analysis provides the basis for setting conservation priorities in La Réunion at the regional and local scale. Implications of the results are discussed with reference to requirements for finer-scale conservation planning.     

Feeding response of the Aldabra giant tortoise (Geochelone gigantea) to island plants showing heterophylly

Aim Heterophylly is present in many plant species on oceanic islands. Almost all of these plants are island endemics, and heterophylly may have evolved as a response to feeding from large insular browsers such as giant tortoises and flightless birds. We tested this anti‐browser hypothesis by feeding Aldabra giant tortoises (Geochelone gigantea) with leaves of native Mauritian plants to see if they distinguished between juvenile and adult leaves and between heteophyllous and homophyllous species. Location Mauritius. Methods In a choice experiment we recorded feeding response of four captive Aldabra giant tortoises to 10 species of Mauritian plants, of which seven were heterophyllous and three homophyllous. Results In general, juvenile leaves of heterophyllous species showed convergence in shape and midrib coloration. Homophyllous foliage was preferred to heterophyllous, and among heterophyllous species adult foliage was preferred to juvenile. Main conclusions Several Mascarene heterophyllous plants show convergence in morphology of juvenile leaves and these are avoided by giant tortoises. This indicates a strong selection history from large browsers such as the giant tortoises. The Mascarene example is in accordance with several other comparable cases of plant‐large browser interactions from other archipelagos.