Annelid from the Neoproterozoic Doushantuo Formation in Northeastern Guizhou,China

Wenghuiia jiangkouensis gen. et sp. nov., characterized by modern annelid taxonomy in morphology and functional biology, is found in black carbonaceous shale from the Neoproterozoic Ediacaran Doushantuo Formation （about 555 Ma） near Wenghui, Jiangkou, northeastern Guizhou Province. The elongate, cylindrical body is composed of many homologous metameres with a true coelom and coelomic pouches. The mouth is at the front of the first segment and the anus at the end of body. A long 11th or 12th segment is probably functionally for procreation, being a clitellum. There are parapodia on the venter of the segments from the rear of the second segment to the front of the clitellum. The setae on all metameres, on the parapodia, and around the anus, differ. In the centre of body, a line probably represents the alimentary canal passing through the body from mouth to anus. A closed vascular system consists of a dorsal vessel at least. W. jiankouensis might represent the oldest discovered ＇modern＇ annelid but it is not a primitive type. It lived on the depositional surface of a shallow sea with an environment of calm-water and abundant light.

Taxonomy and regeneration of a newly recorded Polychaete Capitella teleta(Annelida,Capitellidae)in the coastal water of Shandong,China

The polychaete species of Capitella are widely distributed in the China seas,however little is known about Capitella taxonomy,and specimens collected from China have been identifi ed as Capitella capitata(Fabricius,1780)for more than 50 years.C.capitata was considered to be Arctic and subarctic in distribution,therefore the records of C.capitata in the China seas probably represent other species.A taxonomic study based on the samples collected from the northeast coastal water of Shandong Province reveals a diff erent species,Capitella teleta Blake et al.,2009,which is recorded in the China seas for the fi rst time.Morphologically,C.teleta can be easily distinguished from C.capitata by the absence of neuropodial capillaries on chaetigers 8 and 9.The identity of C.teleta is further supported by genetic distance and phylogenetic analyses assessed from mitochondrial cytochrome c oxidase subunit I(COI)gene.In addition,the regeneration feature of C.teleta was studied through whole mount immunohistochemistry and chemical staining.After amputation,the wound of C.teleta was healed within 24 h,forming a signifi cant regeneration blastema by 3 days post amputation(dpa).By 5 dpa,muscle tissues regenerated,nerve fi bers also extended.By 7 dpa,neurites and muscle tissues are both signifi cantly regenerated.Notably,there are more than ten segments regenerated until 16 dpa.As a highly opportunistic species,Capitella teleta is distributed in China,Japan,Korea,North America,and the Mediterranean.It is expected to be an excellent model for studying developmental genetics and evolution of regeneration.