RESUMEN
Endemics co-occur because they evolved in situ and persist regionally or because they evolved ex situ and later dispersed to shared habitats, generating evolutionary or ecological endemicity centres, respectively. We investigate whether different endemicity centres can intertwine in the region ranging from Alps to Sicily, by studying their butterfly fauna. We gathered an extensive occurrence data set for butterflies of the study area (27,123 records, 269 species, in cells of 0.5 × 0.5 degrees of latitude-longitude). We applied molecular-based delimitation methods (GMYC model) to 26,557 cytochrome c oxidase subunit 1 (COI) sequences of Western Palearctic butterflies. We identified entities based on molecular delimitations and/or the checklist of European butterflies and objectively attributed occurrences to their most probable entity. We obtained a zoogeographic regionalisation based on the 69 endemics of the area. Using phylogenetic ANOVA we tested if endemics from different centres differ from each other and from nonendemics for key ecological traits and divergence time. Endemicity showed high incidence in the Alps and Southern Italy. The regionalisation separated the Alps from the Italian Peninsula and Sicily. The endemics of different centres showed a high turnover and differed in phylogenetic distances, phenology and distribution traits. Endemics are on average younger than nonendemics and the Peninsula-Sicily endemics also have lower variance in divergence than those from the Alps. The observed variation identifies Alpine endemics as paleoendemics, now occupying an ecological centre, and the Peninsula-Sicily ones as neoendemics, that diverged in the region since the Pleistocene. The results challenge the common view of the Alpine-Apennine area as a single "Italian refugium".
Asunto(s)
Mariposas Diurnas , Refugio de Fauna , Animales , Mariposas Diurnas/genética , Variación Genética , Filogenia , SiciliaRESUMEN
Microendemicity, or the condition of some species having local ranges, is a relatively common pattern in nature. However, the factors that lead to this pattern are still largely unknown. Most studies addressing this issue tend to focus on extrinsic factors associated with microendemic distributions, such as environmental conditions, hypothesising a posteriori about underlying potential speciation mechanisms, linked or not to these conditions. Here, we use a multi-faceted approach mostly focusing on intrinsic factors instead, namely diversification dynamics and speciation modes in two endemic sibling genera of leaf beetles with microendemic distributions, Taophila and Tricholapita, in a microendemicity hotspot, New Caledonia. Results suggest that the diversification rate in this lineage slowed down through most of the Neogene and consistently with a protracted speciation model possibly combined with several ecological and environmental factors potentially adding rate-slowing effects through time. In turn, species accumulated following successive allopatric speciation cycles, possibly powered by marked geological and climatic changes in the region in the last 25 million years, with daughter species ranges uncorrelated with the time of speciation. In this case, microendemicity seems to reflect a mature state for the system, rather than a temporary condition for recent species, as suggested for many microendemic organisms.
Asunto(s)
Escarabajos , Especiación Genética , Animales , Evolución Biológica , Nueva Caledonia/epidemiología , FilogeniaRESUMEN
The Eumolpinae leaf beetles of New Caledonia are very diverse, but our knowledge about their diversity is still incomplete. Following a renewed interest in the group in the last two decades, there has been an exponential increase in the number of species described, with species descriptions and taxonomic reassessment ongoing. In this work, the catalogue of New Caledonian Eumolpinae is updated, incorporating all these recent changes, and also indicating the collection where type specimens are currently available. The updated catalogue includes 120 species in 13 genera, and more additions and taxonomic changes, including new combinations, are expected in forthcoming years. Here two new synonymies are reported, namely Dumbeastriata Jolivet, Verma & Mille, 2007 = Taophilacancellata Samuelson, 2010, syn. nov.; and Dematochromatheryi Jolivet, Verma & Mille, 2010 = Dematochromapoyensis Jolivet, Verma & Mille, 2010, syn. nov. Moreover, two species still retaining their original adscription to the genus Colaspis Fabricius, 1801, are treated as incertae sedis. This catalogue represents a useful tool for future taxonomic studies of New Caledonian Chrysomelidae and can assist biodiversity surveys and conservation studies within the archipelago.
RESUMEN
Tricholapita Gómez-Zurita and Cardoso nom. nov. is proposed as the replacement name for the leaf beetle taxon Lapita Gómez-Zurita and Cardoso, 2014, nec Bickel, 2002. Moreover, the rank of Tricholapita stat. nov. is elevated from subgenus of Taophila Heller, 1916 to generic status. Phylogenetic evidence based on mtDNA rrnS sequences and diagnostic morphological characters reveals a new species from the south of Grande Terre in New Caledonia, which is described: Tricholapita reidi sp. nov.
Asunto(s)
Escarabajos , Animales , Mitocondrias , Nueva Caledonia , FilogeniaRESUMEN
Glioblastoma (GBM) comprises distinct subtypes characterized by their molecular profile. Mesenchymal identity in GBM has been associated with a comparatively unfavorable prognosis, primarily due to inherent resistance of these tumors to current therapies. The identification of molecular determinants of mesenchymal transformation could potentially allow for the discovery of new therapeutic targets. Zinc Finger and BTB Domain Containing 18 (ZBTB18/ZNF238/RP58) is a zinc finger transcriptional repressor with a crucial role in brain development and neuronal differentiation. Here, ZBTB18 is primarily silenced in the mesenchymal subtype of GBM through aberrant promoter methylation. Loss of ZBTB18 contributes to the aggressive phenotype of glioblastoma through regulation of poor prognosis-associated signatures. Restitution of ZBTB18 expression reverses the phenotype and impairs tumor-forming ability. These results indicate that ZBTB18 functions as a tumor suppressor in GBM through the regulation of genes associated with phenotypically aggressive properties.Implications: This study characterizes the role of the putative tumor suppressor ZBTB18 and its regulation by promoter hypermethylation, which appears to be a common mechanism to silence ZBTB18 in the mesenchymal subtype of GBM and provides a new mechanistic opportunity to specifically target this tumor subclass. Mol Cancer Res; 15(8); 998-1011. ©2017 AACR.