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Issue: Vol. 30 No. 2: 30 July 2010
Type: Articles
Published: 2010-07-30
DOI: 10.11646/mr.30.2.7
Page range: 113–116
Abstract views: 45
PDF downloaded: 0

Karyotypes in Onchidium struma (Gastropoda: Pulmonata: Systellommatophora)

Key Laboratory of Aquatic Genetic Resources and Aquaculture Ecosystem Certificated by the Ministry of Agriculture, Shanghai Ocean University, 999 Hucheng Huan Road 201306, Shanghai, China.
Key Laboratory of Aquatic Genetic Resources and Aquaculture Ecosystem Certificated by the Ministry of Agriculture, Shanghai Ocean University, 999 Hucheng Huan Road 201306, Shanghai, China.
Key Laboratory of Aquatic Genetic Resources and Aquaculture Ecosystem Certificated by the Ministry of Agriculture, Shanghai Ocean University, 999 Hucheng Huan Road 201306, Shanghai, China.
Key Laboratory of Aquatic Genetic Resources and Aquaculture Ecosystem Certificated by the Ministry of Agriculture, Shanghai Ocean University, 999 Hucheng Huan Road 201306, Shanghai, China.
ovotestis flame-drying diploid haploid chromosome number

Abstract

Karyological analysis was performed on the ovotestis of Onchidium struma with flame-drying techniques. The ovotestis chro-mosome numbers are 18 haploid and 36 diploid without exception. The mitotic chromosome complement has 13 metacentric pairs and five submetacentric pairs with the karyotype formula n= 13M+5SM. This is the first study undertaken on chromo-somes of O. struma with fine mitotic metaphases, making an explanation the ring-shaped chromosomes. Compared with other onchidellids recorded in the literature, the haploid number (18) of O. struma is the same as Onchidium verraculaturn and Onchidella evelinae but is one bivalent more than Onchidella kurodai.