Research Article |
Corresponding author: Eskandar Rastegar Pouyani ( rastegarpouyani45@gmail.com ) Academic editor: Robert Jadin
© 2023 Seyyed Saeed Hosseinian Yousefkhani, Amaal Yasser, Murtada Naser, Mohsen Rezaie-Atagholipour, Majid Askari Hesni, Fariba Yousefabadi, Eskandar Rastegar Pouyani.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hosseinian Yousefkhani SS, Yasser A, Naser M, Rezaie-Atagholipour M, Askari Hesni M, Yousefabadi F, Rastegar Pouyani E (2023) Genetic diversity among sea snakes of the genus Hydrophis (Elapidae, Reptilia) in the Persian Gulf and Gulf of Oman. ZooKeys 1158: 121-131. https://doi.org/10.3897/zookeys.1158.101347
|
Sea snakes of the genus Hydrophis are important components of animal diversity in Iranian waters of the Persian Gulf and Gulf of Oman. Ten species of Hydrophis have been identified from the these waters and, in this study, genetic structure of seven species was compared with other populations in the eastern Indian Ocean and the West Pacific. We found that six species (H. platurus, H. cyanocinctus, H. spiralis, H. schistosus, H. gracilis, and H. lapemiodes) show high genetic similarity with conspecific populations in the Indian Ocean and Australia. However, H. curtus from southern Iran shows a high level of genetic differentiation from conspecific populations in Sri Lanka and Indonesia (0.6% and 6% genetic distance from Sri Lankan samples for 16S and COI gene fragments, respectively). Variation between Iranian and Southeast Asian populations may reflect new genetic lineages and suggest the need of further morphological evaluations to re-evaluate their taxonomic position.
Dispersal, Indian Ocean, microhabitat adaptation, true sea snakes, variation
Sea snakes are a well-known part of marine ecosystems and play an irreplaceable role in the food chain as both predators of small marine fauna and prey for larger predators within their geographical distribution range, which comprises the tropical Indo-Pacific (
Iranian coastal waters of the Persian Gulf and Gulf of Oman are known for their high biological diversity (
In this study, available genetic markers (16S rRNA, COI, and G1888) of species of sea snakes of the genus Hydrophis from the Persian Gulf and the Gulf of Oman were compared to populations in other areas of the Indian Ocean, Southeast Asia, and Indonesia. Examining the genetic structure of the species in the Persian Gulf and comparing them with other populations can illustrate the degree of genetic connection between these populations.
Tissue samples were obtained from the specimens collected in the southern coastal regions of Iran (Persian Gulf and Gulf of Oman) during fieldwork in 2013 (
Two mitochondrial sequences, 16S rRNA (16S) (
The one mitochondrial and the nuclear fragment were concatenated (total length: 1015 bp; 16S: 523 bp; G1888: 492 bp) and COI gene fragment (708 bp) separately were considered to reconstruction phylogenetic trees using Bayesian inference (BI) and maximum-likelihood (ML) methods. The best substitution models for each alignment were: TrNef+I, F81+I, TIM+G, GTR+I+G and TVM+I+G for the first, second, and third codon positions of COI and 16S and G1888, respectively. RaxML v. 7.4.2 (
The relationships among lineages and subclades of Hydrophis were assessed with the mitochondrial 16S rRNA gene, because the number of sequences of 16S covered all species. Aligned sequences were entered in DNAsp v. 5.0. (
Our dataset includes 59 samples containing two mitochondrial gene fragments 16S (495 bp; 77 V; 40 Pi) and COI (661 bp; 158 V; 112 Pi) and one nuclear anonymous fragment G1888 (375 bp; 265 V; 250 Pi) totaling 1531 bp. Both the ML and BI trees show similar topology and therefore we present only the BI tree (Fig.
Tree topology was used to group the sequences and calculate the uncorrected genetic distance (p-distance) among the lineages (Table
P-distances among lineages of sea snakes in 16S gene fragment: 1 = H. spiralis; 2 = H. curtus Iran; 3 = H. cyanocinctus; 4 = H. gracilis; 5 = H. ornatus_Iran; 6 = H. platurus; 7 = H. schistosus; 8 = H. curtus; 9 = H. ornatus; 10 = H. viperinus; 11 = H. obscurus; 12 = H. lapemiodes; 13 = H. brooki.
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | |||||||||||||
2 | 1.8 | ||||||||||||
3 | 1.8 | 1.9 | |||||||||||
4 | 3.6 | 2.5 | 3.7 | ||||||||||
5 | 1.7 | 1.6 | 1.6 | 3.4 | |||||||||
6 | 1.4 | 1.3 | 1.3 | 3.1 | 0.9 | ||||||||
7 | 2.3 | 1.6 | 2.2 | 3.4 | 1.9 | 1.6 | |||||||
8 | 1.2 | 0.6 | 1.3 | 2.5 | 0.9 | 0.6 | 1.6 | ||||||
9 | 1.9 | 1.8 | 1.8 | 3.6 | 0.6 | 1.2 | 1.9 | 1.2 | |||||
10 | 1.4 | 1.3 | 1.3 | 3.1 | 0.9 | 0.6 | 1.6 | 0.6 | 1.2 | ||||
11 | 2.6 | 1.9 | 2.5 | 3.1 | 2.2 | 1.9 | 2.2 | 1.9 | 2.4 | 1.9 | |||
12 | 1.7 | 1.6 | 1.6 | 3.4 | 0.6 | 0.9 | 1.9 | 0.9 | 0.8 | 0.9 | 2.2 | ||
13 | 3.6 | 2.8 | 3.5 | 4.6 | 3.1 | 2.8 | 1.9 | 2.8 | 3.4 | 2.8 | 3.5 | 3.1 |
P-distances among lineages of sea snakes in COI gene fragment: 1 = H. curtus Iran; 2 = H. yanocinctus Iran; 3 = H. gracilis Iran; 4 = H. lapemiodes Iran; 5 = H. ornatus Iran; 6 = H. platurus Iran; 7 = H. schistosus Iran; 8 = H. viperinus Iran; 9 = H. brooki; 10 = H. lapemiodes; 11 = H. schistosus; 12 = H. cyanocinctus; 13 = H. obscurus; 14 = H. curtus; 15 = H. ornatus.
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | |||||||||||||||
2 | 6.7 | ||||||||||||||
3 | 11.2 | 9.1 | |||||||||||||
4 | 7.2 | 4.7 | 9.4 | ||||||||||||
5 | 5 | 4.9 | 10.1 | 4.7 | |||||||||||
6 | 5.3 | 6.3 | 9.8 | 6 | 4.3 | ||||||||||
7 | 5.5 | 5.4 | 10.4 | 5.6 | 4.9 | 5.8 | |||||||||
8 | 6.2 | 5.4 | 10.4 | 5.4 | 3.7 | 5.5 | 5.1 | ||||||||
9 | 8.4 | 8.3 | 11.3 | 7.6 | 6.9 | 6.7 | 8.3 | 6.9 | |||||||
10 | 7 | 2 | 9.4 | 4.9 | 5.1 | 6.5 | 5.6 | 5.6 | 8.1 | ||||||
11 | 6.1 | 5.8 | 11 | 6.5 | 5.8 | 6.1 | 1.6 | 5.8 | 9.2 | 6 | |||||
12 | 6.2 | 1.4 | 9.5 | 5.1 | 4.3 | 5.7 | 5.8 | 5.1 | 8.3 | 1.6 | 6.1 | ||||
13 | 5.5 | 5.4 | 9.1 | 5.6 | 5.1 | 5.5 | 5.4 | 5.4 | 7.1 | 5.6 | 6.3 | 5.1 | |||
14 | 6 | 5.9 | 10.9 | 6.4 | 4.9 | 5.3 | 5.4 | 6.1 | 7.4 | 6.1 | 6.3 | 5.8 | 5.6 | ||
15 | 4.8 | 4.7 | 9.9 | 4.4 | 0.7 | 4 | 4.7 | 3.4 | 6.6 | 4.9 | 5.5 | 4.1 | 4.9 | 4.7 |
Sea snakes are one of the most interesting reptiles in biogeographic and phylogeographic studies (
A recent study on the genetic structure of H. curtus in the Indo-West Pacific revealed the presence of high variation among its populations. The phylogeny indicated that this species was affected by climatic fluctuations in late Pliocene and early Pleistocene (
Other species of the genus, H. platurus, H. cyanocinctus, H. spiralis, H. ornatus, H. schistosus and H. gracilis, included in the analyses, clearly placed within their conspecific Southeast Asian clades, and this may indicate high gene flow and recent (i.e. 10,000 years) dispersal from their source populations (Fig.
The total diversity of the true sea snakes of the genus Hydrophis in the Persian Gulf and Gulf of Oman is 10 species (
We thank L. Lee Grismer, Ann Paterson, Aaron Bauer, and Kamelia Algiers who edited the early draft of the manuscript. This study was partially supported by Iran National Science Foundation (INSF) with project number of 99025967. Tissue samples were collected during field surveys financially supported by the Iranian UNDP/GEF/SGP (grant number: IRA/SGP/OP5/Y3/STAR/BD/13/12-188).
Information of sequences used in this study and those obtained from GenBank
Data type: occurences, accession numbers
Explanation note: Information of sequences used in this study and those obtained from GenBank (sequences with an asterisk, *). Accession numbers for the sequences added to the table. Accession numbers in red related to the new sequences of this study.
Bayesian tree of COI gene fragment that clearly shows variation in Hydrophis curtus clade
Data type: figure