Lobe variation in Sinularia nanolobata Verseveldt, 1977 (Cnidaria: Alcyonacea)

Colonies of Sinularia were collected on the reef flat off south Patong, Phuket, Thailand. The lobes in some of the colonies occur in two forms: (1) those composed of relatively large, spherical or flattened lobules, here termed normal lobes, and (2) those highly divided into many small, rough surfaced lobules, here termed aberrant lobes. The survey revealed that colonies at least 40 cm across were formed of lobes of both morphologies, while smaller colonies were formed only from normal lobes. Regardless of lobe morphology, all specimens collected have similar sclerite characteristics, and were identified as S. nanolobata Verseveldt, 1977, family Alcyoniidae. This species appears to be characterized by intra-specific lobe variation, and such observed intra-colony lobe variation is presented for an octocoral species for the first time. It is speculated that the aberrant lobes might be a result of abnormal regeneration of damaged areas of the colonies as a response either to predation, or some adverse environmental conditions encountered by large colonies in the course of their life span. The aberrant lobes reflect part of the variation of the operational species and emphasize the need to consider total colony morphology during taxonomic practice, and also to assess the ranges of intra-specific variation among alcyoniid octocorals.