Geographic Genetic Structure in Two Laticaudine Sea Kraits,Laticauda laticaudataandLaticauda semifasciata(Serpentes: Elapidae), in the Ryukyu-Taiwan Region as Inferred from Mitochondrial CytochromebSequences

Abstract

The Ryukyu-Taiwan region is an island arch with intervening waters of varying distances and depths. This study examines the geographic genetic structure of two sympatric sea kraits, Laticauda laticaudata and L. semifasciata, in the region, to infer factors affecting the extent of dispersal and other biogeographical traits of these amphibious reptiles. Sequence analyses of the mitochondrial cytochrome b gene revealed four and 16 haplotypes for L. laticaudata (136 individuals) and L. semifasciata (177 individuals), respectively. For both species, population pairwise F ST analyses revealed significant genetic differentiations among islands and island groups, which are separated by deep straits, suggesting that deep waters serve as obstacles for dispersal in both species. Significant genetic differentiation was detected even among islands of the same basin in L. laticaudata, but not in L. semifasciata, and the isolation by distance analyses revealed no significant correlation between geographic and genetic distances in the former species. These results further suggest that L. laticaudata has stronger site fidelity or degree of philopatry than L. semifasciata. Based on the geographic genetic patterns, the historical biogeography of the two species in the Ryukyu-Taiwan region is also discussed.

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

“…We identified three different Cytb haplotypes from our specimens, all which were previously reported from the Taiwan-Ryukyu Archipelago (Fig 1); we adopted the same haplotype names as the previous study [23]. Three specimens from Aewol, Moseolpo, and Gangjeong 2 (Jeju Island) and one from Gori (Korean Peninsula) had the Semi-1 haplotype, a haplotype primarily from the southern Ryukyu Islands (37 out of 38 specimens; [23]).…”

“…semifasciata specimens (from Orchid Island, Taiwan) were included in our study to increase geographic sampling. Sequences from the Ryukyu Islands, Japan were obtained from GenBank [23]. …”

“…The dataset analyzed is a combination of our data (16 individuals) with data from Tandavanitj et al [23] (16 haplotype sequences from 177 individuals).…”

“…semifasciata in Korean waters represents a new and recent appearance [15–17]; Laticauda semifasciata is typically found in the waters around Japan, China including Taiwan, Philippines and Indonesia [22]. Tandavanitj et al [23] found that despite its dispersal abilities, L . semifasciata showed distinctive genetic structure between island groups in Taiwan and Japan.…”

Comprehensive snake venomics of the Okinawa Habu pit viper, Protobothrops flavoviridis, by complementary mass spectrometry-guided approaches

“…Because svMP could include DI domains, both toxin families were combined in the final composition as the svMP/DI part thus forming the second most abundant group. The annotated sequences from fraction 4-13 belong to svMP P-II disintegrin domains, but with ~15 kDa, the observed molecular masses determined from the SDS gel appear too low for svMP P-II (expected molecular masses 30-60 kDa) and too high for single disintegrins (7)(8). It is conceivable, that the identified disintegrin domains originate from degraded P-II or P-III metalloproteinases and contain neighboring sequence parts.…”