Molecular phylogeny and phylogeography of ricefishes (Teleostei: Adrianichthyidae: Oryzias) in Sri Lanka

Abstract

Ricefishes of the genus Oryzias occur commonly in the fresh and brackish waters in coastal lowlands ranging from India across Southeast Asia and on to Japan. Among the three species of Oryzias recorded from peninsular India, two widespread species, O. carnaticus and O. dancena , have previously been reported from Sri Lanka based on museum specimens derived from a few scattered localities. However, members of the genus are widespread in the coastal lowlands of Sri Lanka, a continental island separated from India by the shallow Palk Strait. Although recent molecular phylogenies of Adrianichthyidae represent near‐complete taxon representation, they lack samples from Sri Lanka. Here, based on sampling at 13 locations representative of the entire geographic and climatic regions of the island's coastal lowlands, we investigate for the first time the molecular phylogenetic relationships and phylogeography of Sri Lankan Oryzias based on one nuclear and two mitochondrial markers. Sri Lankan Oryzias comprise two distinct non‐sister lineages within the javanicus species group. One of these is represented by samples exclusively from the northern parts of the island; it is recognized as O. dancena . This lineage is recovered as the sister group to the remaining species in the javanicus group. The second lineage represents a species that is widespread across the island's coastal lowlands. It is recovered as the sister group of O. javanicus and is identified as O . cf. carnaticus . Ancestral‐range estimates suggest two independent colonizations of Indian subcontinent and Sri Lanka by widespread ancestral species of Oryzias during two discrete temporal windows: late Miocene and Plio‐Pleistocene. No phylogeographic structure is apparent in Sri Lankan Oryzias , suggesting that there are no strong barriers to gene flow and dispersal along the coastal floodplains, as is the case also for other generalist freshwater fishes in the island.

Phylogenetic and phylogeographic insights into Sri Lankan killifishes (Teleostei: Aplocheilidae)

“…Its populations lack clear phylogeographic structure, which is unsurprising given its ability to disperse via the brackish waters of the lowland coastal zone, as is the case with Oryzias cf. carnaticus , with which it is commonly syntopic (Sudasinghe et al, 2022). Both haplotype and nucleotide diversities were greater in the southwestern endemics of the Dayi‐Werneri group compared with the widespread generalist A. parvus .…”

Revisi Peta Distribusi Ikan Padi (Adrianichthyidae: Oryzias spp.) Berdasarkan Identifikasi Morfologi di Paparan Sunda Indonesia

“…Collected data were then processed using PAST 4.03 application to construct dendrogram trees and QGIS v.3.26.1 application to make the map. The identification data of the genus Oryzias were interpreted using geographical and evolutionary approaches based on literature studies such as in (Sudasinghe et al, 2022). Unweighted Pair Group Method with Arithmatic Mean (UPGMA) classical analysis is capable of grouping morphological characteristics into a dendrogram, although it will be slightly different from phylogenetics in its interpretation methods.…”

“…Members of the javanicus and celebensis groups can be spotted throughout the Indonesian Archipelago. The javanicus group inhabits Sundaland region, which includes at least three major islands of Borneo, Sumatra and Java, while the celebensis group inhabits Wallacea region, especially Sulawesi (Sudasinghe et al, 2022). Distributional records of the Adrianichthyidae family in Sundaland Indonesia are finite to only two species, Oryzias javanicus and Oryzias hubbsi.…”

Genetic and morphological analysis of complex Giuris group species from Limboto Lake, Gorontalo Province, Indonesia

“…Many endemic fish species in Sulawesi, from families Adrianichthyidae, Zenarchopteridae, Telmatherinidae, and Gobiidae, but potentially including Eleotridae, especially Giuris from their complex G. margaritaceus. There are at least 22 endemic species of Adranichthyidae in Sulawesi from Celebensis group (Sudasinghe et al 2022), and Adrianichthyidae new species in recent years are Oryzias kalimpaaensis (Gani et al 2022) and Oryzias loxolepis (Kobayashi et al 2023). Furthermore, there are at least 14 endemic species from Zenarchopteridae (Kobayashi et al 2020), four species from Telmatherinidae (Chadijah et al 2020), and two species from Gobiidae, and one from Anguillidae (Bandjolu et al 2021).…”