Molecular Systematic Studies Of Thoracotremata Crabs Of China And Application Of Antennae In The Systematic

This study focuses on systematological relationship of Thoracotremata by morphological and molecular characters to supplement the insufficient of Thoracotremata. There are 31 species of 9 families of crabs coming from China in this study.1. The research of molecular characters of ThoracotremataIt shows that the results of NJ tree and BI tree basing on 18S rDNA are mostly the same. All the two results show that Thoracotremata is divided into Ocypodoidea and Grapsoidea, and the support and confidence rate of the two trees are 100,1.00 respectively.The systematological taxonomies of Ocypodoidea and Grapsoidea are the same with other author's, but still existting some differences. Pinnotheres sinensis was in Pinnotheroidea, and whether Pinnotheroidae is in Thoracotremata is still a topic, but the results indicate that Pinnotheres sinensis is close to Octypode ceratophthalmus of Ocypodoidea and far away from Grapsus albolineatus of Grapsoidea by studying the Pinnotheres sinensis. And the topology map of NJ tree and BI tree also shows that Pinnotheres sinensis is in Ocypodoidea So the papers suggest that Pinnotheroidae should be in Thoracotremata, and should not be Pinnotheroidea, and be better in Ocypodoidea. Hapalocarcinus marsupialis was in Cryptochiroidea, but the results of NJ tree and BI tree indicate that Hapalocarcinus marsupialis is closed to Grapsus albolineatus of Grapsoidea and far away from Octypode ceratophthalmus of Ocypodoidea. Hapalocarcinus marsupialis isn't outside of Ocypodoidea and Grapsoidea, but it is in the latter. So the paper doesn't support that Hapalocarcinidae is in Heterotremata, and suggest that Hapalocarcinus marsupialis should be in Grapsoidea of Thoracotremata. Paracleistostoma sp.and Camptandrium sexdentatum of Camptandriidae, Dotilla wichmani of Dotillinae, Macrophthalmus brevis, Macrophthalmus setosus, and Macrophthalmus japonicus of Macrophthalmidae, Mictyris longicarpus of Mictyridae were in Ocypodoidea. But this study finds that all of these are closed to Grapsu albolineatus of Grapsoidea and far away from Octypode ceratophthalmus of Ocypodoidea, and have a high rating. So this study suggests that all of the seven species and Camptandriidae and Mictyridae should be in Grapsoidea. Perisesarma bidens of Sesarmidae, Percnon planissinmum of Plagusiidae, Varuna litterata and Varuna yui of Varunidae were in Grapsoidea. But this study finds that all the four species are closed to Ocypodoidea and far away from Grapsus albolineatus of Grapsoidea, so this study suggests that they should be in Ocypodoidea. Consequently, the paper doesn't support that Camptandrium should be Camptandriidae and Gecarcinidae be Gecarcinidea, out of Grapsoidea.The results of molecular also show that 18S rDNA is fitted to the researches of Thoracotremata and other more advanced systematological relationship, but not fitted to family or subfamily. The families of Grapsoidea are very slowly by looking from NJ tree and BJ tree.2. The research of morphological characters of ThoracotremataThe results of the research of morphological characters of Thoracotremata indicate that the antennule has more characters than antenna does. The results of antennae of crabs are the same with the author's by other morphological characters. It shows that the antennae of crabs could be used for the research of more advanced systematological relationship. The study suggests that whether the antennule is segmentation is a first morphological character in Thoracotremata by studying the morphological characters of antennae. And other morphological characters such as shape of coxa and basis, segment number of exopodite and proportion of every segment, seta on top of exopodite, shape of endopodite, segment number of endopodite and proportion of every segment, seta on top of endopodite and so on. The morphological characters of antennule include shape of basis, proportion of length and width of basis, proportion of length and width of the first and second segment of expodoite, and segment number, proportion of every segment, seta on top of exopodite, and so on. All of those characters could be use for analysising family or subfamily relationships.3. Comparing the results of the morphological and molecular charactersAll of the two methods support dividing Thoracotremata into Ocypodoidea and Grapsoidea. But groups of the two superfamilies included are not the same. There are 22 species in Grapsoidea basing on molecular characters, including Macrophthalmus japonicus, Macrophthalmus setosus, Macrophthalmus brevis, Plagusia immaculate, Gaetice depressus, Metopograpsus quadridentatus, Paracleistostoma sp., Pachygrapsus crassipes, Hemigrapsus penicillatus, Cardisoma carnifex, Camptandrium sexdentatum, Hapalocarcinus marsupialis, Gecarcoidea lalandii, Grapsus albolineatus, Clistocoeloma sinensis, Pachygrapsus marmoratus, Helice tridens tientsinensis, Dotilla wichmani, Eriocheir japonica sinensis, Hemigrapsus sinensis, Mictyris longicarpus. There are 11 species in Ocypodoidea basing on molecular characters, inclucing Perisesarma bidens, Pinnotheres sinensis Tmethypocoelis ceratophora, Varuna litterata, Varuna yui, Deiratonotus cristatum, Ilyoplax deschampsi, Octypode ceratophthalmus, Scopimera globosa, Percnon planissinmum. There are 5 species in Ocypodoidea basing on morphologica charachers, and there are 28 species left in Grapsoidea. Except that there is not samples of antennae in Tmethypocoelis ceratophora and Varuna yui, the results of two methods in Perisesarma bidens, Pinnotheres sinensis, Varuna litterata, Deiratonotus cristatum, Ilyoplax deschampsi, Mictyris longicarpus, Dotilla wichmani, Percnon planissinmum have some differences. So the results of two methods are mostly the same, but still have some differences, this need us do further study.By comparing the results of the morphological and molecular characters, the papers consider that Thoracotremata should have Grapsoidea and Ocypodoidea. It supports that Pinnotheridae and Hapalocarcinidae should be in Thoracotremata, and doesn't support they should be superfamilies, but they are in Ocypodoidea and Grapsoidea. The paper also doesn't support that Gecarcoidae and Camptandriidae change from family to superfamily. The results show that the families of Ocypodoidea and Grapsoidea still need do futher researches.