Sigilina

Sigilina is a genus of parasitic flatworms in the class Trematoda. The precise familial placement of Sigilina has varied among authorities, with some sources placing it in Haploporidae within Plagiorchiida and others treating its relationships as unsettled pending molecular revision.

Species within Sigilina are described as small, leaf-shaped adults with the typical digenean body plan, including an oral sucker and a ventral sucker. Like many trematodes, members are hermaphroditic and possess complex reproductive systems.

Life cycles of most Sigilina species are inferred from related trematodes; they are expected to involve one or more molluscan intermediate hosts and a vertebrate definitive host, though detailed life cycles are known for only a subset of species.

Occurrences have been reported in marine and, less commonly, freshwater settings in various regions, often in association with fish hosts. Taxonomic work continues as molecular data accumulate.

Etymology: The genus name Sigilina derives from the Latin sigillum or related roots, a naming choice by the original describer; exact motivation is not consistently documented.

References: Taxonomic listings such as the World Register of Marine Species (WoRMS) and integrated taxonomic databases recognize Sigilina as a trematode genus, though placement and species composition vary across sources.