The Pedigree Geography Study Of Mantis Shrimp Populations And The Molecular Phylogeny Of Breast Holes In The Coastal Estuary Of China

Stomatopoda is an important group of marine benthic fauna and most species of Stomatopoda live in tropical,subtropical or temperate coastal waters,in which China Sea is the important region of their geographical distribution.Mantis shrimp Oratosquilla oratoria,as an important economic fishery species of Stomatopoda,is a widely distributed species throughout the whole China Sea.This provides the fundamental condition for research on the phylogeography of neritic Stomatopoda.In the study,four genetic markers(nuclear H3 and mitochondrial COI,ND5,COB)and ten morphometric characteristics were used to infer the population genetic diversity and genetic divergence of 15 geographic populations of O.oratoria living in the Chinese coast,and then explore the historical demography due to extreme climate fluctuation in Pleistocene and structural changes of marginal sea for Himalayan orogeny.The results showed that level of genetic diversity in Bohai Sea was the lowest across the whole Chinese coast,while the highest level was in South China Sea relatively.And the results also showed that significant genetic divergence had happened between north and south sea area of China,which showed the typical phylogeographical structure in China Sea.However,genetic homogeneity was revealed among Bohai Sea,Yellow Sea and East China Sea of three north Chinese seas.Results of molecular divergence dating with fossil calibration inferred that the formation of Taiwan Island accelerated the divergence between north and south area,and the opening of the Sea of Japan also contributed to the geographical speciation of marine species.In addition,the opposite ocean currents driving the planktonic larvae of marine species in opposite directions during the reproductive season,further accelerated the genetic divergence of the north and south seas of China,but homogenized the genetic germplasm in the three north sea.But the freshwater flow of the Yangtze River,Yellow River and Zhujiang River was not the major factor of genetic divergence between south and north populations of Stomatopoda.The program S-DIVA on the earliest origin suggested that the ancestral origins of O.oratoria in China were probably in two different areas combination(i.e.,presence in Yellow Sea and South China Sea).Furthermore,the assessment of dispersal-vicariance analysis at the ancestral nodes supported that dispersal event was the dominant factor at the northern ancestral node.However,no sign of dispersal and vicariance was found in the node of the south ancestral node.And rapid population expansion was estimated to have happened approximately 0.05—0.1 Myr during the deglacial period,which was consistent with the time of glacial-interglacial in the end of the Quaternary.Therefore,we hypothesized that rise of sea-level in inter-glacial might be an important factor for rapid population expansion of marine benthic fauna.And difference of phylogeographical structure of sympatric species was for their different swimming ability.Stomatopoda and Thoracotremata are sympatric crustacean taxa in Chinese coast and have experienced the common historical change process of China Sea.In order to choose the right species to make the comparative phylogeography of Stomatopoda and Thoracotremata in China Sea to validate the conclusions in Stomatopoda,we firstly analyzed the problems on higher order of Thoracotremata by molecular systematics and the first antennule morphology.In the recent decades,debate about the taxonomy of marine crabs has been the controversial topic of scientists.In the 1980s,Thoracotremata was divided into 7 superfamilies:Gecarcinoidea,Grapsoidea,Mictyroidea,Pinnotheroidea,Hexapodoidea,ocypodoidea and Hymenosomatoidea.Until 1990s,superfamilies Pinnotheroidea,Hymenosomatoidea and Hexapodoidea were revised as the Heterotremata.And then family Gecarcinidae was moved in superfamily Grapsoidea,Mictyroidea was moved in Ocypodoidea,and family Camptandriidae was promoted to superfamily Camptandriidea.Therefore,the taxonomic problem of Thoracotremata is still a controversial topic.In the study,phylogenetic relationship of Thoracotremata with Portunidae as outgroup was reconstructed using 24 species of 10 families by nuclear molecular marker.Our results supported the validity of four superfamilies(Cryptochiroidea,Pinnotheroidea,Grapsoidea,and Ocypodoidea)of Thoracotremata.But family Macrophthalmidae might be promoted to superfamily Macrophthalmidea,and Gecarcinoidae should be in Ocypodoidea,genus Tmethypocoelis should be in Grapsoidea.The above conclusions were corroborated by morphological characteristics of the first antenna of Thoracotremata in ESEM.