Jaejin Park

Northward dispersal of sea kraits (Laticauda semifasciata) beyond their typical range

Marine reptiles are declining globally, and recent climate change may be a contributing factor. The study of sea snakes collected beyond their typical distribution range provides valuable insight on how climate change affects marine reptile populations. Recently, we collected 12 Laticauda semifasciata (11 females, 1 male) from the waters around southern South Korea—an area located outside its typical distribution range (Japan, China including Taiwan, Philippines and Indonesia). We investigated the genetic origin of Korean specimens by analyzing mitochondrial cytochrome b gene (Cytb) sequences. Six individuals shared haplotypes with a group found in Taiwan-southern Ryukyu Islands, while the remaining six individuals shared haplotypes with a group encompassing the entire Ryukyu Archipelago. These results suggest L. semifasciata moved into Korean waters from the Taiwan-Ryukyu region via the Taiwan Warm Current and/or the Kuroshio Current, with extended survival facilitated by ocean warming. We highlight several contributing factors that increase the chances that L. semifasciata establishes new northern populations beyond the original distribution range.

Complete mitochondrial genome of Schlegel's Japanese gecko Gekko japonicus (Squamata: Gekkonidae)

Abstract We have determined the complete mitochondrial genome of Gekko japonicus, whose status as an endemic or invasive species is currently under debate in Korea. The total genome size is 16 544 bp and consists of 13 protein-coding genes, 2 rRNA (12S and 16S RNA) genes, 22 tRNAs and 2 non-coding regions. The A + T content of the genome is 55.8% (A, 31.2%; C, 29.4%; T, 24.6%; G, 14.9%). Phylogenetic analysis shows that G. japonicus has a close phylogenetic relationship with both G. swinhonis and G. chinensis. Our result will facilitate further genetic studies of this species to ascertain its species status.

First Record of Laticauda semifasciata (Reptilia: Squamata: Elapidae: Laticaudinae) from Korea

The Chinese sea snake Laticauda semifasciata (Reinwardt in Schlegel, 1837) is newly reported from Korean waters based on three specimens collected from Jeju Island, Korea, in August, September, and November 2015. This is the first time that the genus Laticauda and subfamily Laticaudinae has been reported from Korean waters. The subfamily Laticaudinae has ventrals that are four to five times wider than the adjacent dorsals, which are unlike the ventrals that are similar or up to two times wider than adjacent dorsals in the subfamily Hydrophiinae. Laticauda semifasciata is distinct from other species because it has three prefrontals and its rostrals are horizontally divided into two. As the result of this report, four species (L. semifasciata, Hydrophis (Pelamis) platurus, Hydrophis cyanocinctus, and H. melanocephalus) of sea snakes have been reported in Korean waters.

Complete mitochondrial genomes of Scincella vandenburghi and S. huanrenensis (Squamata: Scincidae)

Abstract Here, we report the complete mitochondrial genomes of the skink species Scincella vandenburghi and S. huanrenensis. The mitogenomes were determined to be 17103 bp for S. vandenburghi and 17212 bp for S. huanrenensis. The mitogenomes consist of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and two non-coding regions. We then used the mitogenome data to construct a phylogenetic tree for these two species and an additional 16 species within the suborder Lacertilia.

Phylogenetic relationships of three representative sea krait species (genus Laticauda; elapidae; serpentes) based on 13 mitochondrial genes

Abstract To investigate the phylogenetic relationships of the genus Laticauda to related higher taxa, we compared the sequences of four mitochondrial genes (12S rRNA, 16S rRNA, ND4, Cytb) from three Laticauda species (L. colubrina, L. laticaudata, and L. semifasciata) with those of 55 Asian and Australo-Melanesian elapid species. We also characterized the complete mitogenomes of the three Laticauda species and compared the sequences of 13 mitochondrial genes from Laticauda species with five terrestrial elapid and one viperid species to estimate phylogenetic relationships and divergence times. Our results showed that the genus Laticauda is paraphyletic to terrestrial elapids and diverged from the Asian elapids approximately 16.23 Mya. The mitogenomes of the three Laticauda species commonly encoded 13 proteins, 22 tRNAs, 12S and 16S rRNAs and two control regions and ranged from 17,170 and 17,450 bp in size. The L. colubrina mitogenome was more similar to that of L. laticaudata than that of L. semifasciata. The divergence time among the three Laticauda clades was estimated at 8–10 Mya, and a close phylogenetic relationship between L. colubrina and L. laticaudata was found. Our results contribute to our understanding of the evolutionary history of sea kraits.

First case of ranavirus-associated mass mortality in a natural population of the Huanren frog (Rana huanrenensis) tadpoles in South Korea

ABSTRACT Globally, ranavirus is often responsible for the mass mortality of a variety of captive and wild amphibians. In Asia, several mass mortality cases of captive amphibians by ranavirus are known, but one mass mortality case in the wild has been reported in a non-endemic larval bullfrog population in Japan. In order to verify factors involved in mass mortality of Rana huanrenensis tadpoles (> 200 tadpoles) in a mountain stream in South Korea, we investigated possible infections by ranavirus, chytrid fungus, and lethal bacteria by conducting PCR assays of pathogens with specific primers. We found that all R. huanrenensis tadpoles collected (two alive and ten carcasses) showed positive PCR results for two different ranavirus primer sets targeting partial genes of a major capsid protein (MCP). The identified MCP sequence was more closely related to Rana catesbeiana virus JP MCP, isolated from invasive bullfrog tadpoles in Japan. We could not detect any lethal bacteria or chytrid fungus in the specimens. Our finding is the first report in Asia that ranavirus is involved in the mass mortality of endemic wild amphibians.