Pachycordyle is a genus of cnidarians (hydrozoans) belonging to the family Bougainvilliidae within the class Hydrozoa and phylum Cnidaria. The genus was established by August Weismann in 1883, with the type species being Pachycordyle napolitana.
Distribution: Species of this genus are found in Europe, Southeastern Asia, and Northern America, with some species inhabiting brackish water environments.
Description: Members of this genus are small hydrozoans that form simple or colonial hydroids. They typically have erect, unbranched stems arising from a creeping hydrorhiza, terminating in a single hydranth. The stems and hydrocauli are covered by a corrugated perisarc. The hydranths are club-shaped.
Species: The genus includes the following recognized species:
- Pachycordyle conica Kramp, 1959
- Pachycordyle degenerata (Mayer, 1904)
- Pachycordyle globulosa Kramp, 1959
- Pachycordyle kubotai Stepanjants, Timoshkin, Anokhin & Napara, 2000
- Pachycordyle lineata Kramp, 1959
- Pachycordyle mashikoi (Itô, 1952)
- Pachycordyle michaeli (Berrill, 1948)
- Pachycordyle napolitana Weismann, 1883
- Pachycordyle pusilla (Motz-Kossowska, 1905)
Taxonomic note: The systematic status of some species within this genus has undergone revision. For instance, Pachycordyle michaeli (commonly known as the brackish sea fir) was previously placed in other genera (e.g., Clavopsella) before being reassigned to Pachycordyle by Schuchert (2004, 2007).
