Laetmonice iocasica sp.nov.,a new polychaete species(Annelida:Aphroditidae)from seamounts in the tropical Western Pacific,with remarks on L.producta Grube,1877

Laetmonice Kinberg,1856 is a remarkable genus characterized by having harpoon notochaetae in the polychaete family Aphroditidae.We describe a new species of Laetmonice,Laetmonice iocasica sp.nov.,found from seamounts on the Caroline Ridge in the tropical Western Pacific.The new species is readily distinguished from congeners,particularly those distributed in the Indo-Pacific Ocean by possessing45 segments with 18 pairs of elytra,and the tuberculated harpoon notochaetae in the elytrigerous segments,which are replaced by tuberculated notochaetae without recurved fangs on segments 4 and 5.Laetmonice iocasica sp.nov.is closely related to L.producta Grube,1877,but differs in both morphology and the genetic distance of the mitochondrial cytochrome oxidase subunit I(COI)sequences.Laetmonice producta Grube,1877 contained five varieties reported in various marine areas,which have been raised to species level.However,the records of L.producta from the Sagami B ay and Suruga B ay in Japan and in the south-eastern Australia remain obscure and probably represent a different species.The data indicate that L.producta,which was originally described from Kerguelen Islands in the Southern Ocean and later commonly found on the Antarctic shelf,is probably distributed only at high latitudes of the Southern Hemisphere.

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.