Jean-Luc Gattolliat

Global diversity of mayflies (Ephemeroptera, Insecta) in freshwater

The extant global Ephemeroptera fauna is represented by over 3,000 described species in 42 families and more than 400 genera. The highest generic diversity occurs in the Neotropics, with a correspondingly high species diversity, while the Palaearctic has the lowest generic diversity, but a high species diversity. Such distribution patterns may relate to how long evolutionary processes have been carrying on in isolation in a bioregion. Over an extended period, there may be extinction of species, but evolution of more genera. Dramatic extinction events such as the K-T mass extinction have affected current mayfly diversity and distribution. Climatic history plays an important role in the rate of speciation in an area, with regions which have been climatically stable over long periods having fewer species per genus, when compared to regions subjected to climatic stresses, such as glaciation. A total of 13 families are endemic to specific bioregions, with eight among them being monospecific. Most of these have restricted distributions which may be the result of them being the relict of a previously more diverse, but presently almost completely extinct family, or may be the consequence of vicariance events, resulting from evolution due to long-term isolation.

Trans-oceanic and endemic origins of the small minnow mayflies (Ephemeroptera, Baetidae) of Madagascar

We investigated the relative importance of dispersal and vicariance in forming the Madagascar insect fauna, sequencing approximately 2300 bp from three rRNA gene regions to investigate the phylogeny of Afrotropical small minnow mayflies (Ephemeroptera: Baetidae). Six lineages contained trans-oceanic sister taxa, and variation in genetic divergence between sister taxa revealed relationships that range from very recent dispersal to ancient vicariance. Dispersal was most recent and frequent in species that spend the larval stage in standing water, adding to evidence that these evolutionarily unstable habitats may select for ecological traits that increase dispersal in insects. Ancestral state likelihood analysis suggested at least one Afrotropical lineage had its origin in Madagascar, demonstrating that unidirectional dispersal from a continental source may be too simplistic. We conclude that the Malagasy mayfly fauna should be considered in a biogeographical context that extends beyond Madagascar itself, encompassing trans-oceanic dispersal within multiple lineages.

Conserving Madagascar's Freshwater Biodiversity

Abstract The island nation of Madagascar, an international conservation priority, is now also recognized as a global hotspot for freshwater biodiversity. Three emerging characteristics of Madagascars threatened freshwater biota deserve increased attention from the scientific and conservation communities. First, species richness is not low, as was once assumed for both the freshwater fishes and the invertebrates. Second, many species are restricted to a specific region or even to single river basins. Often these species are also limited to streams or rivers draining primary forest habitat. Finally, many of the islands freshwater fishes are basal taxa, having diverged earlier than any other extant members of their clade. As such, these taxa assume disproportional phylogenetic importance. In the face of ongoing environmental threats, links among microendemism, forest stream specialization, and basal phylogenetic position highlight the importance and vulnerability of these species and provide a powerful incentive for immediate conservation action.

Towards a new paradigm in mayfly phylogeny (Ephemeroptera): combined analysis of morphological and molecular data

This study represents the first formal morphological and combined (morphological and molecular) phylogenetic analyses of the order Ephemeroptera. Taxonomic sampling comprised 112 species in 107 genera, including 42 recognized families (all major lineages of Ephemeroptera). Morphological data consisted of 101 morphological characters. Molecular data were acquired from DNA sequences of the 12S, 16S, 18S, 28S and H3 genes. The Asian genus Siphluriscus (Siphluriscidae) was supported as sister to all other mayflies. The lineages Carapacea, Furcatergalia, Fossoriae, Pannota, Caenoidea and Ephemerelloidea were supported as monophyletic, as were many of the families. However, some recognized families (for example, Ameletopsidae and Coloburiscidae) and major lineages (such as Setisura, Pisciforma and Ephemeroidea among others) were not supported as monophyletic, mainly due to convergences within nymphal characters. Clade robustness was evaluated by multiple methods and approaches.

Endemism and diversification in freshwater insects of Madagascar revealed by coalescent and phylogenetic analysis of museum and field collections

The biodiversity and endemism of Madagascar are among the most extraordinary and endangered in the world. This includes the islands freshwater biodiversity, although detailed knowledge of the diversity, endemism, and biogeographic origin of freshwater invertebrates is lacking. The aquatic immature stages of mayflies (Ephemeroptera) are widely used as bio-indicators and form an important component of Malagasy freshwater biodiversity. Many species are thought to be microendemics, restricted to single river basins in forested areas, making them particularly sensitive to habitat reduction and degradation. The Heptageniidae are a globally diverse family of mayflies (>500 species) but remain practically unknown in Madagascar except for two species described in 1996. The standard approach to understanding their diversity, endemism, and origin would require extensive field sampling on several continents and years of taxonomic work followed by phylogenetic analysis. Here we circumvent this using museum collections and freshly collected individuals in a combined approach of DNA taxonomy and phylogeny. The coalescent-based GMYC analysis of DNA barcode data (mitochondrial COI) revealed 14 putative species on Madagascar, 70% of which were microendemics. A phylogenetic analysis that included African and Asian species and data from two mitochondrial and four nuclear loci indicated the Malagasy Heptageniidae are monophyletic and sister to African species. The genus Compsoneuria is shown to be paraphyletic and the genus Notonurus is reinstalled for African and Malagasy species previously placed in Compsoneuria. A molecular clock excluded a Gondwanan vicariance origin and instead favoured a more recent overseas colonization of Madagascar. The observed monophyly and high microendemism highlight their conservation importance and suggest the DNA-based approach can rapidly provide information on the diversity, endemism, and origin of freshwater biodiversity. Our results underline the important role that museum collections can play in molecular studies, especially in critically endangered biodiversity hotspots like Madagascar where entire species or populations may go extinct very quickly.

DNA-based association of adults and larvae in Baetidae (Ephemeroptera) with the description of a new genus Adnoptilum in Madagascar

Abstract The mayfly fauna of Madagascar is highly diverse and largely endemic. Many species remain undescribed, and many species are known from only the larval or adult life stage. The high biodiversity in Madagascar and in other areas has led to an increasing reliance on DNA-based approaches to taxonomy, i.e., to define species boundaries and to associate different developmental stages. We used the general mixed Yule-coalescent (GMYC) model to combine population- and species-level sequence variation of mitochondrial deoxyribonucleic acid (mtDNA) to detect species boundaries in Baetidae mayflies (Ephemeroptera). Starting with a database of 240 sequences (57 species), significant clustering of newly sequenced larvae allowed us to establish 1 new species and 1 new combination and to associate adult and larval stages for both. A molecular phylogeny using additional nuclear (18S) and mtDNA (rrnS, rrnL) gene regions recovered the new species and new combination as a monophyletic group, distinct from other Afrotropical lineages. Therefore, we established a new genus, Adnoptilum, endemic to Madagascar. Adnoptilum gen. n. can be distinguished from other species in both the imaginal and adult stages and appears to belong to the Bugilliesia complex. We conclude that routine sampling of population- and species-level genetic diversity, combined with coalescent-based methods of species delineation, has great potential to become a standard procedure for the study of poorly known taxonomic groups.

Distribution and population genetic variation of cryptic species of the Alpine mayfly Baetis alpinus (Ephemeroptera: Baetidae) in the Central Alps

BackgroundMany species contain evolutionarily distinct groups that are genetically highly differentiated but morphologically difficult to distinguish (i.e., cryptic species). The presence of cryptic species poses significant challenges for the accurate assessment of biodiversity and, if unrecognized, may lead to erroneous inferences in many fields of biological research and conservation.ResultsWe tested for cryptic genetic variation within the broadly distributed alpine mayfly Baetis alpinus across several major European drainages in the central Alps. Bayesian clustering and multivariate analyses of nuclear microsatellite loci, combined with phylogenetic analyses of mitochondrial DNA, were used to assess population genetic structure and diversity. We identified two genetically highly differentiated lineages (A and B) that had no obvious differences in regional distribution patterns, and occurred in local sympatry. Furthermore, the two lineages differed in relative abundance, overall levels of genetic diversity as well as patterns of population structure: lineage A was abundant, widely distributed and had a higher level of genetic variation, whereas lineage B was less abundant, more prevalent in spring-fed tributaries than glacier-fed streams and restricted to high elevations. Subsequent morphological analyses revealed that traits previously acknowledged as intraspecific variation of B. alpinus in fact segregated these two lineages.ConclusionsTaken together, our findings indicate that even common and apparently ecologically well-studied species may consist of reproductively isolated units, with distinct evolutionary histories and likely different ecology and evolutionary potential. These findings emphasize the need to investigate hidden diversity even in well-known species to allow for appropriate assessment of biological diversity and conservation measures.

The family Baetidae (Insecta: Ephemeroptera): synthesis and future challenges

The systematics of the Baetidae has been the subject of much attention during the last three decades, with descriptions of new species and genera as well as several generic revisions. The family now encompasses about 100 genera and 900 species which constitute one-quarter of the worlds mayfly diversity. It is thus an opportune time to evaluate the pertinence of these works. The diversity of the Baetidae of the different realms is discussed with emphasis on the rate of endemism and biogeographic affinities. We have also tried to identify the geographical areas where we need more data. The Afrotropics and Neotropics possess the most diversified fauna with the highest degree of endemism. The faunas of the Palaearctic and Nearctic realms are better known but are less diversified especially at a generic level. Oriental and Australasian faunas are still poorly known but are expected to be diversified especially in the tropical regions.

First contribution to the mayflies of Jordan

Abstract Up to now, the mayfly fauna of Jordan has been completely unknown. Based on material recently collected at approximately 30 localities, a first contribution is provided. At least seven species of Ephemeroptera belonging to three different families occur in Jordan. With four species, the Baetidae is by far the most common and diversified family. Two new species, Nigrobaetis vuatazi Gattolliat & Sartori n.sp. and Baetis monnerati Gattolliat & Sartori n.sp., are described in both larval and imaginal stages. The association of the ontogenetic stages was based on mitochondrial DNA (COI gene). Nigrobaetis vuatazi is closely related to Nigrobaetis arabiensis Gattolliat & Sartori, 2008, recently described from United Arab Emirates, but differs notably from European species especially Nigrobaetis niger (Linnaeus, 1761) and Nigrobaetis digitatus (Bengtsson, 1912). Baetis monnerati belongs to the buceratus species-group, which is known to be very common in the Levant but less frequent in Central Europe. The two other baetid species, Cloeon dipterum (Linnaeus, 1761) and Procloeon pennulatum (Eaton, 1870), are widely distributed in the Western Palaearctic and have already been reported from the Levant. Caenidae are represented by Caenis antoniae Malzacher, 1992 and Caenis parabrevipes Malzacher, 1992, and Leptophlebiidae by Choroterpes (Euthraulus) ortali Sartori, 1992. These three species were originally described from Israel and have not been reported since then. These reports increase their geographic range to the east and are of significant importance for conservation purposes as their former distribution was extremely restricted.

Two New Genera of Baetidae (Ephemeroptera; Insecta) from Madagascar

Two new genera of Baetidae (Ephemeroptera), Scutoptilum gen. n. and Echinopus gen. n., are described to accommodate three new species from Madagascar: Scutoptilum verrucosum sp. n., Echinopus giboni sp. n., Echinopus minutus sp. n.. They all share a unique apomorphy; they possess a subapico-transverse arc of long setae on the outer margin of femora. Scutoptilum presents important adaptations to fast flowing waters and mouthparts modified for scraping. Moreover, Scutoptilum shows an unusual general habitus with a prothorax broadly expanded laterally, forewing pads extremely developed and shape of the head subrectangular. Echinopus appears less derived and possesses more plesiomorphic features. Both genera are closely related to the Afrotropical genus Afroptilum and belong to the Centroptiloides complex.