The morphology of seven specimens of Chrysaora chinensis(Scyphomedusae,Semaestomae)obtained from four sites off the coast of Peninsular Malaysia was examined.Morphological characteristics of C.chinensis that encompass...The morphology of seven specimens of Chrysaora chinensis(Scyphomedusae,Semaestomae)obtained from four sites off the coast of Peninsular Malaysia was examined.Morphological characteristics of C.chinensis that encompasses structures such as the bell,tentacles,oral arms,stomach,manubrium,radial canals and gonads were described in detail.A total of 107 specimens that represented C.chinensis populations of four coastal areas of Peninsular Malaysia(East-Central,East-North,West-Central,and West-North)were also analysed for shape variation using geometric morphometric analysis.Procrustes superimposition,Principal Component Analysis(PCA)and Canonical Variate Analysis(CVA)were applied to the images of gastrovascular pouches of C.chinensis to extract the shape information.Independent contrasts were used for comparisons between shapes.There were no significant differences in shape variation between all the specimens based on the PCA results.However,CVA results showed shape variations between specimens taken from the four areas of Peninsular Malaysia,especially with higher magnitudes of Mahalanobis distances between the east and west coast areas,including between East-Central and East-North,but lower magnitudes were detected between the West-Central and West-North.展开更多
Quadrapyrgites is a microfossil reported with embryonic and post-embryonic stages from the lower Cambrian small shelly fauna of South China,and is closely related to Olivooides.Their development mode and systematic po...Quadrapyrgites is a microfossil reported with embryonic and post-embryonic stages from the lower Cambrian small shelly fauna of South China,and is closely related to Olivooides.Their development mode and systematic positions are hot topics in palaeoembryology and evolutionary biology in recent years,but are still under debate.Here,we present a description on the growth pattern and post-embryonic development of Quadrapyrgites quadratacris recovered from the lower Cambrian of South China.The growth zone of Q.quadratacris is situated at the oral end,and new terminal lobes are generated within the oral aperture.The terminal lobes are first in control of the opening and closure of the tubes,and later transferred to be crests,thus elongating the tubes.The post-embryonic development is characterized by a one-by-one addition of crests on the post-embryonic tissue,and an ontogenetic sequence with crest number from 1 to 17 is reconstructed.During the ontogeny,the embryonic tissue remains stable in size and morphology.The oral aperture is the only opening of the tubes,while a possible anus on the apical end does not occur.Quadrapyrgites was proposed to be the sister group of Olivooides,and now this is strengthened by the identical growth pattern and post-embryonic development.The comprehensive data from anatomy,growth pattern and post-embryonic development reject the stemlineage cycloneuralian affinity for Quadrapyrgites and Olivooides,and instead support a coronate scyphozoan hypothesis.展开更多
基金The University of Malaya,Kuala Lumpur,Malaysia through UMRG Grant under contract No.RG104-11SUSUMRP Grant under contract No.RU006E-2014the postgraduate sponsorship from the Ministry of Higher Education(MyBrain scholarship programme)
文摘The morphology of seven specimens of Chrysaora chinensis(Scyphomedusae,Semaestomae)obtained from four sites off the coast of Peninsular Malaysia was examined.Morphological characteristics of C.chinensis that encompasses structures such as the bell,tentacles,oral arms,stomach,manubrium,radial canals and gonads were described in detail.A total of 107 specimens that represented C.chinensis populations of four coastal areas of Peninsular Malaysia(East-Central,East-North,West-Central,and West-North)were also analysed for shape variation using geometric morphometric analysis.Procrustes superimposition,Principal Component Analysis(PCA)and Canonical Variate Analysis(CVA)were applied to the images of gastrovascular pouches of C.chinensis to extract the shape information.Independent contrasts were used for comparisons between shapes.There were no significant differences in shape variation between all the specimens based on the PCA results.However,CVA results showed shape variations between specimens taken from the four areas of Peninsular Malaysia,especially with higher magnitudes of Mahalanobis distances between the east and west coast areas,including between East-Central and East-North,but lower magnitudes were detected between the West-Central and West-North.
基金supported by the National Natural Science Foundation of China(41072012 and 41102003)the State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences(113115and 20132107)+1 种基金the Key Project of Central University Fund(CHD2012ZD017)The Ninth‘‘Challenge Cup’’Competition of College Students’Extracurricular Academic and Technological Achievements,Chang’an University,College students’ innovative entrepreneurial training program(201410710144 and 201410710105)
文摘Quadrapyrgites is a microfossil reported with embryonic and post-embryonic stages from the lower Cambrian small shelly fauna of South China,and is closely related to Olivooides.Their development mode and systematic positions are hot topics in palaeoembryology and evolutionary biology in recent years,but are still under debate.Here,we present a description on the growth pattern and post-embryonic development of Quadrapyrgites quadratacris recovered from the lower Cambrian of South China.The growth zone of Q.quadratacris is situated at the oral end,and new terminal lobes are generated within the oral aperture.The terminal lobes are first in control of the opening and closure of the tubes,and later transferred to be crests,thus elongating the tubes.The post-embryonic development is characterized by a one-by-one addition of crests on the post-embryonic tissue,and an ontogenetic sequence with crest number from 1 to 17 is reconstructed.During the ontogeny,the embryonic tissue remains stable in size and morphology.The oral aperture is the only opening of the tubes,while a possible anus on the apical end does not occur.Quadrapyrgites was proposed to be the sister group of Olivooides,and now this is strengthened by the identical growth pattern and post-embryonic development.The comprehensive data from anatomy,growth pattern and post-embryonic development reject the stemlineage cycloneuralian affinity for Quadrapyrgites and Olivooides,and instead support a coronate scyphozoan hypothesis.
