Comparative seascape genetics of co-distributed intertidal snails Monodonta spp. in the Japanese and Ryukyu archipelagoes

Abstract

Recent molecular ecological studies have focused on how the relationships between physical and ecological factors influence marine biogeography. Comparative phylogeography using closely related species is a powerful approach to evaluate the role of ecological traits in the genetic variation of marine organisms. In the present study, we compared ecological traits and genetic variation in 3 species of the intertidal snail genus Monodonta that co-occur in the Japanese and Ryukyu archipelagoes. We found that M. labio was dominant in sheltered habitats and M. perplexa was dominant in wave-exposed habitats, while M. confusa showed no habitat specificity. This indicates that M. labio and M. perplexa are habitat specialists regarding wave exposure, while M. confusa is a generalist. M. labio and M. perplexa showed lower genetic diversity and greater genetic differentiation among populations than M. confusa. Our findings support the specialist-generalist variation hypothesis in a well-connected marine environment.

High-throughput SNPs dataset reveal restricted population connectivity of marine gastropod within the narrow distribution range of peripheral oceanic islands

“…After larval settlement and metamorphosis, M. confusa matures to a shell height of approximately 10 mm, which takes 1 to 2 years. Around the Japanese archipelago , a previous molecular study on M. confusa detected a significant genetic population structure, but the level of differentiation was smaller than that of closely related species 46 . For Monodonta sp.…”

“…The mtDNA of M. confusa displays a higher level of genetic diversity around the Japanese archipelago and the continental side than Monodonta sp. 46 , 53 . This reduced genetic diversity of Monodonta sp.…”

Genetically isolated population of the coastal species with high dispersal potential: the case of the sentinel crab <i>Macrophthalmus japonicus</i> (Brachyura: Macrophthalmidae) in Japan

“…Such a pattern in the genetic population structure and the history of population establishment was not reported from Mutsu Bay (e.g., Kojima et al 2004, Kawane et al 2008, Hirase et al 2012, Hirase & Ikeda 2014, Yamazaki 2020, Yamazaki et al 2021. For example, the population at Asamushi, Mutsu Bay, of an intertidal crab species Gaetice depressus (De Haan, 1833) (Varunidae), which is distributed in both sides of Honshu Island, is not genetically differentiated from other sites on Honshu Island in the COI gene (Kawane et al 2008).…”

Populations of the Intertidal Crab Macrophthalmus banzai are Not Grouped by Latitude: Taiwan Population is Genetically Closer to the Populations in the Japanese Mainland Than the Ryukyu Islands

“…The genetic differences between remote populations (the Japanese mainland and Taiwan Island) of these species may be due to the short larval duration-3 days for Monodonta spp. (Sasaki, 1985;Yamazaki et al, 2021); 5-7 days for F. albicostatus (Chan and Leung, 2007); P. nipponica possesses a larval period but its duration has not been determined (Kimura et al, 2002)-compared with that of intertidal crabs such as M. banzai and T. arcuata that do not show clear genetic differences between these areas. Also, the populations of Hexechamaesipho pilsbryi (Hiro, 1936) were divided into northern (Shimoda, Japan to Okinawa Island) and southern (Taiwan to Sabah, Malaysia) lineages (Tsang et al, 2013), but the genetic differences between the lineages are large for intra-specific variation (4.7-6.7% in COI) and the difference may represent inter-specific variation.…”