Species Diversity And Mitochondrial Phylogenomics Of Stylommatophora Of Terrestrial Molluscs In The Wuyi Mountains

Located at the junction of Fujian and Jiangxi provinces,the Wuyi Mountains have a subtropical humid climate and are a biodiversity hotspot in China.The Wuyi Mountains belong to the boundary between South China and Central China of the Oriental boundary in the zoogeographic fauna.The formation and differentiation of its species is at the center of southeastern China,and terrestrial molluscs species are also very abundant.Author investigated the terrestrial molluscs in the Wuyi Mountains from September 2019 to November 2020,analyzed the species composition,diversity index and fauna characteristics,and the similarities of terrestrial molluscs species in 7national and provincial nature reserves in Wuyi Mountains were compared.Based on the next generation sequencing,the complete mitochondrial genomes of 10 species of terrestrial molluscs were sequenced,and the phylogenetic analysis was carried out with the complete mitochondrial genomes of 37 species of terrestrial molluscs published in Genbank.The main findings are as follows:1.154 species and subspecies of terrestrial molluscs were recorded in the Wuyi Mountains,belonging to 1 class,3 subclasses,4 orders,19 families and 42 genera,among which 30 species were newly recorded from Jiangxi Province.In terms of species composition,the Bradybaenidae has the most species,including 38 species in7 genera,Ariophantidae including 30 species in 3 genera.The dominant species were Bradybaena similaris,Acusta Ravida redfieldi,Kaliella munipurensis and Phiololomycus bilineatus.In terms of distribution,the species diversity of terrestrial molluscs in the northern section of the Wuyi Mountains is relatively rich,33 families,58 genera and 137 species;next in the middle section,total 28 families,50 genera and86 species;and there are fewer terrestrial shellfish species in the southern section,18 families,23 genera and 45 species.2.The fauna analysis showed that the main species composition of Wuyi Mountains terrestrial molluscs were the Oriental realm species.There were 107 species of Oriental realm terrestrial molluscs accounting for 69.48% of the total species;5species in the Palaearctic realm,accounting for 3.25% of the total species;17 species of transboundary distribution,accounting for 11.04% of the total species.3.The complete mitochondrial genome of 10 species of terrestrial molluscs of Stylommatophora was sequenced.The sequence length ranged from 14,103 to 15,674 bp,and the nucleotide composition showed an AT preference.There was a high A + T content in the mitochondrial genome and the protein coding gene composition.It was found that the highest was in the Anadenus yangtzeensis,the content of A + T was 76.8%and 76.4%,respectively,and the the smallest is the Acusta despecta,with AT-content of 65% and 64.3% respectively.4.The complete mitochondrial genome sequences of 47 species of terrestrial molluscs were analyzed,including 22 different gene arrangements.Among them,the complete mitochondrial genome of Mirus frinianus has been rearranged by proteincoding gene and t RNA(nad3-trn S1-trn I-trn G)gene cluster,which is a novel way of gene order.This is also the first mitochondrial genome of the family Enidae.5.Based on the complete mitochondrial genome,the phylogeny of 47 species of terrestrial molluscs belonging to 21 families was analyzed.The results showed that the superfamily Pupilloidea and family Enidae were clustered together,this result supported that the superfamily Pupilloidea was a monophyletic group;and that other important groups such as Helicoidea and Arionoidea were monophyletic,a large proportion of the evolutionary tree.Pupilloidea and Clausilioidea were sister-group relationship.