Arctic species of the cheilostome bryozoan Microporella, with a redescription of the type species

Abstract

This investigation focuses on the diversity and taxonomy of species of Microporella found north of the Arctic Circle. Firstly, however, a neotype is chosen for the Mediterranean type species M. ciliata (Pallas) in order to stabilize the taxonomy of this “pseudocosmopolitan” species, which has been recorded in the past from the Arctic. Study of type and other material using scanning electron microscopy shows that only two Arctic species of Microporella can be recognized, M. arctica Norman and M. klugei sp. nov. The first of these is characterized by a large ascopore divided by thin radial septa and situated close to the proximal rim of the orifice. Microporella klugei sp. nov. differs in having a smaller, undivided ascopore situated in a more proximal position on the frontal shield. Both Arctic species are notable among Microporella species for having a high proportion of autozooids without associated avicularia.

Keywords:

• Arctic
• Bryozoa
• Microporella
• taxonomy
• new species

Acknowledgements

Mary Spencer Jones (Department of Zoology, NHM), Jean‐Marc Gagnon (CMN) and Nina Denisenko (ZI) are thanked for their assistance with literature and collections. This study was commenced during an EU Marie Curie fellowship (BRYOARC) and completed thanks to the financial support to one of us (PK) from the EU programme DYNARC and ArcOD mini grant. PDT acknowledges funding from the JSPS for research on Microporella hosted in the laboratory of Professor S.F. Mawatari (University of Hokkaido). Francesco Toscano kindly supplied specimens of M. ciliata from the Bay of Naples. The comments of two anonymous referees led to improvements.