An Anomalous Hatchery-Reared Biwa Rock Catfish, Silurus lithophilus (Teleostei: Siluridae), with an Adipose Fin-Like Projection

作者：Kitagawa Tetsuro^*; Hosoya Kazumi

来源：Zoological Science, 2015, 32(5): 435-437.

DOI：10.2108/zs140296

• dysplasia
• evolution
• artificial breeding
• fin-ray
• endemic species

An anomalous individual with an adipose fin-like projection was discovered during seedling production of Biwa rock catfish, Silurus lithophilus (Teleostei: Siluridae). The external shape of the projection resembled an adipose fin, but soft rays were clearly observed within it. The projection was proximally supported by a series of pterygiophores and by 14 soft rays. The projection can be explained as: I, homologous with a primitive adipose fin, which occurred as a result of localized ontogenetic reversion; II, an extra fin that occurred as a result of abnormal expression of a regeneration mechanism; III, a remnant of a dorsal fin and/or a second dorsal fin; and IV, an inversion phenomenon of the polarity in the formation process of the anal fin.

• 出版日期2015-10