In search of phylogenetic congruence between molecular and morphological data in bryozoans with extreme adult skeletal heteromorphy

Abstract

The taxonomy of cyclostome bryozoans, both recent and fossil, is founded almost entirely on characters of the mineralized skeleton. However, the adequacy of these characters is now being questioned by molecular sequence data. In this study we construct a molecular tree using ssrDNA and lsrDNA sequences and identify a clade of New Zealand cyclostomes containing species exhibiting widely different morphologies. In particular, Diaperoecia purpurascens (Hutton), a species assigned to the suborder Tubuliporina on the basis of adult skeletal morphology, is shown to be closely related to New Zealand species assigned to Heteropora, including H. neozelanica (Busk), which has a very different adult skeleton and is traditionally placed in the suborder Cerioporina. A new species resembling the Antarctic genus Hastingsia, ‘H’. whitteni sp. nov., from North Island, New Zealand, is found to belong to the same clade, despite being placed conventionally in a different family (Hastingsiidae) from both Diaperoecia (Diaperoeciidae) and Heteropora (Cerioporidae). These results challenge the utility of adult skeletal morphology in cyclostome taxonomy. In contrast to the striking dissimilarity between the adult skeletons of D. purpurascens and ‘Hastingsia’ whitteni compared with New Zealand species of Heteropora, morphological similarities in early colony development, as well as possibly the presence of a gizzard, corroborate the molecular interpretation of their close relationships. Greater attention should be paid in the future to early astogenetic characters in cyclostome taxonomy.http://zoobank.org/urn:lsid:zoobank.org:pub:CE81CE34-DE0F-43B6-A46E-E086F3F5E76D

Key words:

• Bryozoa
• Cyclostomata
• early astogeny
• molecular phylogeny
• morphology
• New Zealand
• taxonomy

Acknowledgements

PDT is grateful to Dr Lee Hsiang Liow (University of Oslo) for the opportunity to visit New Zealand for geological fieldwork in January 2014 when the specimen shown in Fig. 20 was collected. We thank Joanne Porter (Heriot-Watt University, Edinburgh) for her help with the collection of specimens, and the NHM sequencing facility for their sequencing expertise. The sequenced material of ‘Hastingsia’ whitteni sp. nov. was collected as part of a commercial project for Trans Tasman Resources (TTR) Ltd (TTR11301 Benthos and TTR11301 Deepwater); TTR is thanked for permission to use the specimen for research purposes.

Disclosure Statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

Research on cyclostome bryozoans from New Zealand was commenced during the tenure of a British Council Link Programme Grant in the mid-1990s, and continued during NERC Grant (NE/E015298/1; October 2007–October 2010). DPG's research was supported by NIWA through Coasts and Oceans Research Programme 2 (Marine Biological Resources) taxonomy project COBR1502.