Historically, the diving duck, Baer’s Pochard (Aythya baeri) was widely distributed in East and South Asia, but according to a recent estimate, its global population is now less than 1000 individuals. To date, the mitochondrial genome ofA. baerihas not been deposited and is not available in GenBank. Therefore, we aimed to sequence the complete mitochondrial genome of this species. The genome was 16,623 bp in length, double stranded, circular in shape, and contained 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one non-coding control region. Many structural and compositional similarities were discovered betweenA. baeriand the other threeAythyamitochondrial genomes. Among 13 protein-coding genes of the fourAythyaspecies, the fastest-evolving gene wasATP8while the slowest-evolving gene wasCOII.Furthermore, the phylogenetic tree of Anatidae based on Bayesian inference and maximum likelihood methods showed that the relationships among 15 genera of the Anatidae family were as follows:Dendrocygnawas an early diverging lineage that was fairly distant from the other ingroup taxa;Cygnus,Branta, andAnserwere clustered into one branch that corresponded to the Anserinae subfamily; andAythya,Asarcornis,Netta,Anas,Mareca,Mergus,Lophodytes,Bucephala,Tadorna,Cairina, andAixwere clustered into another branch that corresponded to the Anatinae subfamily. Our target species and three otherAythyaspecies formed a monophyletic group. These results provide new mitogenomic information to support further phylogenetic and taxonomic studies and genetic conservation of Anatidae species.

Alligator gar Atractosteus spatula originates from North America but has been introduced into China recently. Considered an invasive fish, it may cause losses in the diversity and number of local species and in fish catch due to its predation on numerous aquatic animals in non-native habitats. A comprehensive study of this alien invasive species’ existing spatial patterns in relation to climatic variables is critical to understanding the conditions amenable to its distribution and controlling its further spread into potential range areas. We used MaxEnt and QGIS species distribution modeling to estimate the likely biogeographical range of A. spatula in China based on 36 validated distribution records and seven selected environmental variables. The highly suitable area was found primarily in a series of provinces extending from inland to coastal regions, covering southwest to south, central and east China. The model identified the minimum temperature of the coldest month (Bio6) and mean temperature of the warmest quarter (Bio10) as the strongest predictors of A. spatula distribution. The findings could offer scientific guidance for managing and preventing the spread of this invasive fish and hint at controlling invasive aquatic fauna.