Emeritus Professor Abby Smith
Scientists studying the seafloor around southern Aotearoa New Zealand have uncovered an unexpected diversity of ancient marine creatures, revealing that a group once thought to be little more than a surviving remnant of prehistoric life is still evolving and thriving.
Researchers have identified 11 species of hornerid bryozoans in the Horneridae family, including seven species that are newly recognized.
The discovery challenges earlier assumptions about these small and often overlooked marine animals, which have a fossil history stretching back more than 250 million years.
Rather than being evolutionary leftovers confined to a few ecological niches, the newly studied hornerids appear to represent a diverse and successful group in the southern waters of Aotearoa.
Ancient Creatures Hidden Beneath the Sea
Bryozoans are small marine invertebrates best known for producing intricate, lace-like skeletons.
Although individual animals are tiny, bryozoans can form structures that provide habitat for other marine organisms. In deep waters around Aotearoa New Zealand, they can therefore play an important ecological role as structure-forming organisms.
The group has an extremely long history.
Bryozoans have existed for more than 250 million years, while most of the ancient groups associated with their early evolutionary history are now extinct.
The new research shows that at least one lineage has remained remarkably successful.
11 Species Reveal Unexpected Diversity
Scientists previously believed that only two species of hornerid bryozoans occurred in Aotearoa New Zealand.
The new research paints a very different picture.
Researchers describe, illustrate and name 11 species across three genera. Seven of the species are newly recognized, while the study also includes one new genus and reinstates another genus.
The specimens were collected from the seafloor around southern Aotearoa, extending from Cook Strait to the subantarctic islands.
The findings demonstrate that hornerid bryozoans in the region are considerably more diverse than scientists previously understood.
Combining DNA and Morphology
The researchers used a combination of molecular and morphological approaches to distinguish the species.
Morphological analysis examines physical characteristics, while molecular research provides information about relationships between organisms.
Using both approaches allowed the researchers not only to identify different species but also to investigate their evolutionary relationships.
The work demonstrates why taxonomy is more than simply assigning names to organisms.
As lead author Emeritus Professor Abby Smith of the University of Otago explained, taxonomists can uncover relationships between species and provide greater certainty about which organism is which.
That certainty is particularly important when apparently similar organisms actually represent distinct species.
A Group Once Thought to Be an Evolutionary Remnant
The discovery surprised the research team because hornerid bryozoans belong to a group known as cyclostomes.
Smith said researchers had previously regarded this group as something of a remnant from the Paleozoic Era, which spans roughly 540 to 250 million years ago.
Many other bryozoan groups from that ancient period disappeared.
Cyclostomes, by contrast, survived in relatively small ecological niches around the world.
The new findings suggest that this interpretation may underestimate their evolutionary success.
Hornerids appear to have continued evolving, changing their life strategies and diversifying in the southern waters of Aotearoa.
In other words, they are not simply surviving relics of an ancient ecosystem.
They are an evolving and diverse group.
Seven Newly Recognized Species
Of the 11 species described in the study, seven are new species.
Three of the species were given names that commemorate people or organizations connected with research in the region.
Hornera polaris honours the research vessel RV Polaris II, while Hornera girvanae and Hornera currieae honour scientists Elizabeth Girvan and Kim Currie.
Both researchers had a major influence on understanding seafloor organisms in the area.
The names therefore preserve part of the history of marine research alongside the scientific discovery itself.
Why Taxonomy Matters for Conservation
The discovery also has important implications for conservation.
If scientists do not know that a species exists, it becomes much more difficult to study its ecology, monitor its populations or protect it from environmental threats.
Smith emphasized this point, noting that species cannot effectively be conserved, managed, studied or understood if they have not been recognized.
The discovery of previously unrecognized species therefore changes the scientific picture of the seafloor ecosystem.
What once appeared to be a relatively limited group may actually contain a much greater range of biodiversity.
Life on the Southern Seafloor
The researchers examined material from southern Aotearoa, including waters stretching from Cook Strait toward the subantarctic islands.
This broad geographic range provides an opportunity to investigate how hornerid species are distributed across different parts of the southern marine environment.
Their lace-like skeletons can also create physical structures on the seafloor, potentially providing habitat for other organisms.
The newly documented diversity suggests that these animals deserve greater attention when scientists assess the biological communities living in deeper waters around New Zealand.
More Species May Be Waiting to Be Identified
The study may not represent the end of the story.
Researchers already have specimens from northern New Zealand that have yet to be fully examined, classified, identified and named.
Those samples could contain additional species.
If so, the number of recognized hornerid species in Aotearoa could increase again.
The possibility highlights how much biological diversity can remain hidden in marine environments, particularly among organisms that are small, structurally similar and difficult to identify without detailed morphological and molecular analysis.
Research Published in Scientific Journal
The findings were published in the Zoological Journal of the Linnean Society.
Emeritus Professor Abby Smith of the University of Otago collaborated with Dr Helen Jenkins, Dr Paul Taylor and Dr Andrea Waeschenbach of the Natural History Museum in London.
Their research combines field specimens, morphological examination and molecular analysis to establish a clearer picture of hornerid diversity and evolutionary relationships.
Conclusion
The discovery of 11 hornerid bryozoan species in southern Aotearoa New Zealand is changing scientists' understanding of a group with an extraordinarily ancient history.
Once considered a relatively obscure remnant of the Paleozoic world, hornerids appear to be remarkably diverse, evolutionarily active and successful in southern New Zealand waters.
Seven of the 11 species are newly recognized, while the research also establishes changes in the classification of the group.
The discovery carries an important conservation lesson as well: biodiversity cannot be properly studied or protected if scientists do not know that individual species exist.
And researchers suspect the story may not be finished.
Specimens from northern New Zealand are still awaiting detailed examination, meaning that even more previously unrecognized species could eventually emerge from the nation's surrounding waters.
FAQ
What are bryozoans?
Bryozoans are small marine invertebrates known for their often lace-like skeletons. They can form structures that provide habitat for other organisms.
How old are bryozoans?
The supplied source states that bryozoans have existed for more than 250 million years.
How many hornerid species were discovered?
Researchers identified 11 species in the study, including seven newly recognized species.
Where were the species found?
The specimens came from the seafloor around southern Aotearoa New Zealand, between Cook Strait and the subantarctic islands.
How were the species identified?
Scientists used both molecular and morphological approaches to distinguish the species and investigate their relationships.
What are cyclostomes?
Cyclostomes are a group of bryozoans that survived from an extremely ancient period. The researchers had previously regarded them as something of a remnant group, but the new findings indicate considerable diversity among hornerids.
Why are the discoveries important for conservation?
Scientists need to know which species exist before they can properly study, manage and conserve them.
What are the newly named species?
Three species were given names honouring the research vessel RV Polaris II and scientists Elizabeth Girvan and Kim Currie: Hornera polaris, Hornera girvanae and Hornera currieae.
Could more species be discovered?
Yes. Researchers have specimens from northern New Zealand that still require examination and classification, and these could reveal additional species.
