A western representative of an eastern clade: phylogeographic history of the gypsophilous plant Nepeta hispanica

The preference of certain plant species for gypsum soils leads to disjunct population structures that are thought to generate island-like dynamics potentially influencing biogeographic patterns at multiple evolutionary scales. Here, we study the evolutionary and biogeographic history of Nepeta hispanica, a western Mediterranean plant associated with gypsum soils and displaying a patchy distribution with populations very distant from each other. Three approaches were used: (a) interspecific phylogenetic analyses based on nuclear DNA sequences of the ITS region to unveil the relationships and times of divergence between N. hispanica and its closest relatives; (b) phylogeographic analyses using plastid DNA regions trnS-trnG and psbJ-petA to evaluate the degree of genetic isolation between populations of N. hispanica, their relationships and their genetic diversity; and (c) ecological niche modelling to evaluate historical distributional changes. Results reveal that N. hispanica belongs to an eastern Mediterranean and Asian clade diversified in arid environments since the Miocene-Pliocene. This species represents the only extant lineage of this clade that colonized the western Mediterranean, probably through the northern Mediterranean coast (southern Europe). Present Iberian populations display a high plastid genetic diversity and, even if geographically distant from each other, they are highly connected according to the distribution of plastid haplotypes and lineages. This can be explained by a scenario involving a complex history of back-and-forth colonisation events, facilitated by a relative stability of suitable conditions for the species across the Iberian Peninsula throughout the Quaternary.

Extensive species diversification and marked geographic phylogenetic structure in the Mesoamerican genus Stenopelmatus (Orthoptera: Stenopelmatidae: Stenopelmatinae) revealed by mitochondrial and nuclear 3RAD data

The Jerusalem cricket subfamily Stenopelmatinae is distributed from south-western Canada through the western half of the United States to as far south as Ecuador. Recently, the generic classification of this subfamily was updated to contain two genera, the western North American Ammopelmatus, and the Mexican, and central and northern South American Stenopelmatus. The taxonomy of the latter genus was also revised, with 5, 13 and 14 species being respectively validated, declared as nomen dubium and described as new. Despite this effort, the systematics of Stenopelmatus is still far from complete. Here, we generated sequences of the mitochondrial DNA barcoding locus and performed two distinct DNA sequence-based approaches to assess the species’ limits among several populations of Stenopelmatus, with emphasis on populations from central and south-east Mexico. We reconstructed the phylogenetic relationships among representative species of the main clades within the genus using nuclear 3RAD data and carried out a molecular clock analysis to investigate its biogeographic history. The two DNA sequence-based approaches consistently recovered 34 putative species, several of which are apparently undescribed. Our estimates of phylogeny confirmed the recent generic update of Stenopelmatinae and revealed a marked phylogeographic structure within Stenopelmatus. Based on our results, we propose the existence of four species-groups within the genus (the faulkneri, talpa, Central America and piceiventris species-groups). The geographic distribution of these species-groups and our molecular clock estimates are congruent with the geological processes that took place in mountain ranges along central and southern Mexico, particularly since the Neogene. Our study emphasises the necessity to continue performing more taxonomic and phylogenetic studies on Stenopelmatus to clarify its actual species richness and evolutionary history in Mesoamerica.

Isotopic reconstruction of Proboscidean habitats and diets on enigmatic island of Sulawesi

Sulawesi is known for its complex geological and biogeographic history, which is reflected in their extinct and extant faunal assemblage. Evidence of oldest terrestrial fauna in Sulawesi was found in the Early Pleistocene sediment and evolved since then. Despite being mostly isolated from the mainland Southeast Asia; four successive Proboscidean taxa have been found from the southern part of the island. The four taxa are: Stegoloxodon celebensis, Stegodon sompoensis, Stegodon sp. B, and cf. Palaeoloxodon namadicus, in which respective taxa are included in successive faunal stages. The aim of this research is to reconstruct the diet and palaeoenvironment of these Proboscidean taxa by incorporating stable isotope analysis with the fossil faunal record, geology, and stratigraphy. Stable carbon (δ13C) and oxygen (δ18O) isotope analysis were especially used in this study. Our result suggests that Stegoloxodon celebensis and Stegodon sompoensis were flexible feeders and were able to adapt to different niches, from closed canopy forest to open vegetation, while the diets of Stegodon sp. B, Celebochoerus heekereni and cf. Palaeoloxodon namadicus suggest that they were more specialized.

From Patagonia to Indonesia: plant fossils highlight West Gondwanan legacy in the Malesian flora

Rainforests with the chinquapin Castanopsis and the yellowwood conifer Dacrycarpus occur today throughout Indonesia and the larger Malesian ecoregion, but they represent, in part, a history of survival stretching tens of millions of years and thousands of kilometers to the palaeo-Antarctic. Unlike New World and African tropical rainforests, the Malesian flora’s history is closely tied to tectonic introductions from exotic terranes, and thus, much palaeobotanical data about the origins of the Malesian rainforest comes from those terranes. For example, South America, Antarctica, and Australia remained adjacent until the Eocene final separation of Gondwana, and warm climates promoted high-latitude dispersals among those landmasses. Australia’s subsequent northward movement led to the late Oligocene Sahul-Sunda collision and the uplift of New Guinea, allowing the introductions into Malesia of survivor taxa that were once widespread in mesic Gondwanan rainforests. In Patagonian Argentina, the prolific Laguna del Hunco (52.2 Ma) site preserves abundant and well-preserved fossils of an unexpectedly large number of lineages whose living relatives characteristically associate in perhumid, lower montane “oak-laurel” rainforests of Malesia, especially in New Guinea. These taxa include the angiosperms Castanopsis (Fagaceae), Gymnostoma (rhu, Casuarinaceae), Alatonucula (extinct engelhardioid Juglandaceae), Eucalyptus (gums, Myrtaceae), Ceratopetalum (coachwood, Cunoniaceae), Lauraceae (laurel family), and Ripogonum (supplejack, Ripogonaceae); conifers in Cupressaceae (cypress family: Papuacedrus), Araucariaceae (dammars and relatives: Agathis and Araucaria Section Eutacta), and Podocarpaceae (yellowwoods: Dacrycarpus, Podocarpus, and a species similar to Phyllocladus); and the fern Todea (king fern, Osmundaceae). Many of these records are the only occurrences of the respective taxa in South America, living or fossil, vastly extending their past ranges and thus the biogeographic history of part of the Malesian mountain flora. The living-fossil taxa inhabit, and several dominate, critical watershed areas of high endemism and biodiversity in Malesia’s endangered tropical-montane rainforests. In Malesia itself, there have been very few Cenozoic palaeobotanical investigations for about a century or more. To remedy this situation and improve understanding of the evolution of the Malesian flora in situ, we have begun palaeobotanical fieldwork in collaboration with Professor Yahdi Zaim and ITB, along with international colleagues. So far, we have discovered several promising new fossil sites in the Eocene-Oligocene of West Sumatra (Sangkarewang and Sawahlunto formations) and South Kalimantan (Tanjung Formation), and I will report preliminary observations.

The oldest known record of a ground sloth (Mammalia, Xenarthra, Folivora) from Hispaniola: evolutionary and paleobiogeographical implications

Sloths were among the most diverse groups of land vertebrates that inhabited the Greater Antilles until their extinction in the middle-late Holocene following the arrival of humans to the islands. Although the fossil record of the group is well known from Quaternary deposits in Cuba, Hispaniola, and Puerto Rico, remains from older units are scarce, limiting our understanding of their evolution and biogeographic history. Here we report the oldest known fossil ground sloth from Hispaniola, represented by an unassociated partial tibia and scapula that are recognized as a single taxon from the late Miocene-early Pliocene of the Dominican Republic. The combination of characters observed on the tibia suggests a close relationship with Megalocnus, otherwise only known from the Pleistocene–Holocene of Cuba. These fossils fill a temporal gap between those previously known from the early Miocene of Cuba and those from Pleistocene–Holocene deposits in the region and provide additional support for a continuous presence of the group in the Greater Antilles since the Oligocene.

Global plant-frugivore trait matching is shaped by climate and biogeographic history

Species interactions are influenced by the trait structure of local multi-trophic communities. However, it remains unclear whether mutualistic interactions in particular can drive trait patterns at the global scale, where climatic constraints and biogeographic processes gain importance. Here we evaluate global relationships between traits of frugivorous birds and palms (Arecaceae), and how these relationships are affected, directly or indirectly, by assemblage richness, climate and biogeographic history. We leverage a new and expanded gape size dataset for nearly all avian frugivores, and find a positive relationship between gape size and fruit size, i.e., trait matching, which is influenced indirectly by palm richness and climate. We also uncover a latitudinal gradient in trait matching strength, which increases towards the tropics and varies among zoogeographic realms. Taken together, our results suggest trophic interactions have consistent influences on trait structure, but that abiotic, biogeographic and richness effects also play important, though sometimes indirect, roles in shaping the functional biogeography of mutualisms.

It takes two to tango – Phylogeography, taxonomy and hybridization in grass snakes and dice snakes (Serpentes: Natricidae: Natrix natrix, N. tessellata)

Using two mitochondrial DNA fragments and 13 microsatellite loci, we examined the phylogeographic structure and taxonomy of two codistributed snake species (Natrix natrix, N. tessellata) in their eastern distribution area, with a focus on Turkey. We found evidence for frequent interspecific hybridization, previously thought to be extremely rare, and for backcrosses. This underscores that closely related sympatric species should be studied together because otherwise the signal of hybridization will be missed. Furthermore, the phylogeographic patterns of the two species show many parallels, suggestive of a shared biogeographic history. In general, the phylogeographies follow the paradigm of southern richness to northern purity, but the dice snake has some additional lineages in the south and east in regions where grass snakes do not occur. For both species, the Balkan Peninsula and the Caucasus region served as glacial refugia, with several mitochondrial lineages occurring in close proximity. Our results show that the mitochondrial divergences in both species match nuclear genomic differentiation. Yet, in the former glacial refugia of grass snakes there are fewer nuclear clusters than mitochondrial lineages, suggesting that Holocene range expansions transformed the glacial hotspots in melting pots where only the mitochondrial lineages persisted, bearing witness of former diversity. On the other hand, the deep mitochondrial divergences in N. tessellata across its entire range indicate that more than one species could be involved, even though lacking microsatellite data outside of Turkey prevent firm conclusions. On the contrary, our microsatellite and mitochondrial data corroborate that N. megalocephala is invalid and not differentiated from sympatric populations of N. natrix. For Cypriot grass snakes, our analyses yielded conflicting results. A critical assessment of the available evidence suggests that N. natrix is a genetically impoverished recent invader on Cyprus and taxonomically not distinct from a subspecies also occurring in western Anatolia and the southern Balkans. Based on combined mitochondrial and nuclear genomic evidence we propose that for grass snakes the following subspecies should be recognized in our study region: (1) Natrix natrix vulgaris Laurenti, 1768, southeastern Central Europe and northern Balkans; (2) Natrix natrix moreoticus (Bedriaga, 1882), southern Balkans, western Anatolia, and Cyprus; and (3) Natrix natrix scutata (Pallas, 1771), eastern Anatolia, Caucasus region, Iran, northeastern distribution range (from eastern Poland and Finland to Kazakhstan and the Lake Baikal region). Thus, Natrix natrix cypriaca (Hecht, 1930) becomes a junior synonym of N. n. moreoticus and Natrix natrix persa (Pallas, 1814) becomes a junior synonym of N. n. scutata. Due to insufficient material, we could not resolve the status of Natrix natrix syriaca (Hecht, 1930) from the Gulf of İskenderun, southeastern Turkey.