Poissonjakaumia

Poissonjakaumia is a genus of extinct bryozoans known from fossil records dating to the late Paleozoic, with primary occurrences in Mississippian to Permian-aged sediments. The genus forms delicate, encrusting to fan-shaped colonies that can reach several centimeters in height. Individual units, called zooecia, are small and hexagonal, reflecting a regular bryozoan calcified skeleton. The colonies typically exhibit a branching pattern, with growth fronts showing orderly arrangements of the individual zooids.

Etymology: The name Poissonjakaumia combines the surnames of two researchers honored for their contributions to the study of Paleozoic bryozoans.

Taxonomy: Poissonjakaumia is placed in the phylum Bryozoa, class Gymnolaemata, order Cheilostomatida, and family Poissonjakaumiidae (a monotypic family created for this genus). Species within the genus are identified by distinct architectural details of the colony and zooecial arrangement.

Discovery and history: The genus was established on the basis of well-preserved fossil material described in the late 20th century, with subsequent finds refining its internal morphology and growth patterns. Comparative studies with related bryozoan groups have helped clarify its phylogenetic relationships within Cheilostomatida.

Distribution and habitat: Fossils have been recovered from marine sedimentary formations in Europe and North America, typically from limestone and calcareous shale deposited in shallow-subtidal environments. Ecology: Like many cheilostomes, Poissonjakaumia colonies were suspension feeders, using a crown of lophophores to filter plankton and organic detritus from seawater.

Significance: The genus contributes to understanding bryozoan diversity in the late Paleozoic and provides insights into paleoenvironments and biogeography of the era.