Monospecific and bispecific genera are of special concern as they represent unique phylogenetic/evolutionary trajectories within larger clades.In addition,as phylogenetically older taxa are supposed to be exposed to h...Monospecific and bispecific genera are of special concern as they represent unique phylogenetic/evolutionary trajectories within larger clades.In addition,as phylogenetically older taxa are supposed to be exposed to higher rarity and extinction risk,monospecific and bispecific genera may be intrinsically more prone to extinction risks than multispecies genera,although extinction risks also depend on the ecological and biological strategy of the species.Here,the distribution across biogeographical zones and the levels of threat to 2 speciose orders of mammals(monospecific and bispecific genera of Rodentia and Soricomorpha)are investigated in order to highlight major patterns at the worldwide scale.In Rodentia,39.7%of the genera(n=490)were monospecific and 17.9%were bispecific.In Soricomorpha,44.4%of the total genera(n=45)were monospecific and 15%were bispecific.There was a positive correlation between the number of monospecific genera and the total number of genera per family.Peaks of monospecific and bispecific genera richness were observed in Neotropical,Oriental and Afrotropical regions in rodents and in the Palearctic region in soricomorphs.Range size was significantly uneven across biogeographic region in rodents(with larger ranges in Nearctic and Oriental regions and smaller ranges in the Australian region),but there was no difference across biogeographic regions in terms of range size in soricomorphs.Most of the monospecific and bispecific genera occurred in forest habitat in both taxa.The frequency distribution of the monospecific and bispecific genera across IUCN categories did not differ significantly from the expected pattern using the total rodent genera and the multispecies genera.展开更多
Integrative taxonomy,a multi-disciplinary approach adding modern techniques to traditional morphology-based methods(e.g.molecular and morphological criteria),can play an important role in bioinvasion research to ident...Integrative taxonomy,a multi-disciplinary approach adding modern techniques to traditional morphology-based methods(e.g.molecular and morphological criteria),can play an important role in bioinvasion research to identify introduced taxa,discover pathways of introduction and inform authorities to control and prevent future introductions.The present study is the first on introduced populations of Callosciurus,Asiatic tree squirrels,known as potentially invasive species in Europe(Italy,Belgium and France).We combined molecular(mitochondrial DNA markers:CoxI,D-loop)and morphometric analysis on skulls,comparing them to the widest morphological and molecular datasets ever assembled for Callosciurus.Squirrels collected in Italy and Belgium share the same haplotypes and skull characteristics,but are conspicuously different from the French population in Antibes.Genetic data revealed close similarity between French squirrels and Pallas’s squirrels,Callosciurus erythraeus,from Taiwan,China.Italian and Belgian squirrels formed an independent taxonomic lineage in genetic analyses,whose taxonomic rank needs further investigation.The morphological and morphometric characteristics of these 2 populations are,however,similar to known specimens assigned to Callosciurus erythraeus.These results may indicate a common origin for the populations found in Belgium and Italy.In contrast,French specimens suggest an independent introduction event of squirrels originating from Asia.展开更多
文摘Monospecific and bispecific genera are of special concern as they represent unique phylogenetic/evolutionary trajectories within larger clades.In addition,as phylogenetically older taxa are supposed to be exposed to higher rarity and extinction risk,monospecific and bispecific genera may be intrinsically more prone to extinction risks than multispecies genera,although extinction risks also depend on the ecological and biological strategy of the species.Here,the distribution across biogeographical zones and the levels of threat to 2 speciose orders of mammals(monospecific and bispecific genera of Rodentia and Soricomorpha)are investigated in order to highlight major patterns at the worldwide scale.In Rodentia,39.7%of the genera(n=490)were monospecific and 17.9%were bispecific.In Soricomorpha,44.4%of the total genera(n=45)were monospecific and 15%were bispecific.There was a positive correlation between the number of monospecific genera and the total number of genera per family.Peaks of monospecific and bispecific genera richness were observed in Neotropical,Oriental and Afrotropical regions in rodents and in the Palearctic region in soricomorphs.Range size was significantly uneven across biogeographic region in rodents(with larger ranges in Nearctic and Oriental regions and smaller ranges in the Australian region),but there was no difference across biogeographic regions in terms of range size in soricomorphs.Most of the monospecific and bispecific genera occurred in forest habitat in both taxa.The frequency distribution of the monospecific and bispecific genera across IUCN categories did not differ significantly from the expected pattern using the total rodent genera and the multispecies genera.
文摘Integrative taxonomy,a multi-disciplinary approach adding modern techniques to traditional morphology-based methods(e.g.molecular and morphological criteria),can play an important role in bioinvasion research to identify introduced taxa,discover pathways of introduction and inform authorities to control and prevent future introductions.The present study is the first on introduced populations of Callosciurus,Asiatic tree squirrels,known as potentially invasive species in Europe(Italy,Belgium and France).We combined molecular(mitochondrial DNA markers:CoxI,D-loop)and morphometric analysis on skulls,comparing them to the widest morphological and molecular datasets ever assembled for Callosciurus.Squirrels collected in Italy and Belgium share the same haplotypes and skull characteristics,but are conspicuously different from the French population in Antibes.Genetic data revealed close similarity between French squirrels and Pallas’s squirrels,Callosciurus erythraeus,from Taiwan,China.Italian and Belgian squirrels formed an independent taxonomic lineage in genetic analyses,whose taxonomic rank needs further investigation.The morphological and morphometric characteristics of these 2 populations are,however,similar to known specimens assigned to Callosciurus erythraeus.These results may indicate a common origin for the populations found in Belgium and Italy.In contrast,French specimens suggest an independent introduction event of squirrels originating from Asia.
