Zhadan A.E., Vortsepneva E.V., Tsetlin A.B. 2012. Redescription and biology of Cossura pygodactylata Jones, 1956 (Polychaeta: Cossuridae) in the White Sea // Invertebrate Zoology. Vol.9. No.2: 115–125 [in English].
White Sea Biological Station, Biological Faculty, Moscow State University, Moscow 119234, Russia; e-mail: azhadan@wsbs-msu.ru
doi: 10.15298/invertzool.09.2.04
KEY WORDS: Cossura pygodactylata, Cossura longocirrata, taxonomy, juvenile development, size population structure, geographical distribution, Arctic.
ABSTRACT: Cossurids are quite abundant on soft substrata in the White Sea. Adult and juvenile specimens were studied using light and scanning electron microscopy. Originally the White Sea species was referred to Cossura longocirrata Webster et Benedict, 1887 but the present study revealed its affiliation to the close species C. pygodactylata Jones, 1956. Lateral organs are described for the first time in cossurids. Juveniles differ from adults by the presence of a prototroch, the pygidium without appendages, and hardly detectable division of the body into regions. Population size structure was investigated in four samples taken from July to November. Size-frequency histogram showed a bimodal distribution.