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NUI Galway Study Resolves Enigma of Oceanic Squids

5th October 2021
Flying squid (family Ommastrephidae) sitting on the deep-sea floor at the Fangorn bank (Ireland)
Flying squid (family Ommastrephidae) sitting on the deep-sea floor at the Fangorn bank (Ireland) Credit: Louise Allcock, NUI Galway

Lineages among oceanic squids which have been said to puzzle researchers for over a century have been resolved by scientists at NUI Galway (NUIG).

A team at the NUIG Ryan Institute has been able to name the different family groups and says this provides important clues as to how squid evolved.

The findings have been published in the Zoological Journal of the Linnean Society.

Lead study author Dr Fernando Angel Fernández-Álvarez at NUIG's School of Natural Sciences spent five years collecting tissue from squid during oceanic cruises and when sampling from commercial trawlers.

Oceanic squid on the bottom of the ocean floor with relatively close-up view of tentacles and suckers. Oceanic squid on the bottom of the ocean floor with relatively close-up view of tentacles and suckers. Photo: NOAA OKEANOS Explorer Progra, 2013 Northeast U. S. Canyons Expedition

“The aim was to solve the relationships among this amazing group of animals. I believe this study is an important milestone for the field and a good starting point for performing in-depth studies on the evolutionary trends that shape the huge diversity of oceanic squids,” he said.

“Our research could also be useful as we try to understand how our oceans will respond to ever-increasing pressures from human activities,” he added.

The research team used a method known as genome skimming to reveal the full sequence of DNA and identify relationships among squid.

Each of the discovered groups was named based on the rules dictated by the International Code of Zoological Nomenclature, the team says.

It suggests that scientists will have a way to accurately identify and describe the biodiversity of these marine creatures in the future.

Oceanic squids are a highly significant part of the marine food web.

They are voracious predators and provide the main meal of toothed whales and other endangered megafauna.

They include the largest group of commercially fished cephalopods, the flying squids.

The researchers also discovered what they say are "unexpected and as yet, unexplained, relationships".

"For instance, delicate deep-sea glass squids are more closely related to powerful muscular Humboldt squids and to the unusual monogamous diamondback squid, than to other oceanic squids," the NUIG team states.

“How these remarkable changes in form came about is not yet understood," Prof Louise Allcock of NUIG's School of Natural Sciences, Ryan Institute, explained.

An oceanic squid resting on the seafloor, changing colour as it sits on its elbows to breathe. Photo: NOAA OKEANOS Explorer Program, 2013 Northeast U. S. Canyons ExpeditionAn oceanic squid resting on the seafloor, changing colour as it sits on its elbows to breathe. Photo: NOAA OKEANOS Explorer Program, 2013 Northeast U. S. Canyons Expedition

“Oceanic squids are an amazingly diverse group of cephalopods – molluscs with arms and tentacles like squid, octopus and cuttlefish - with fascinating adaptations to their watery environment," she said.

" For example, glass squids use their body cavity as a fluid-filled buoyancy chamber, while chiroteuthids develop fishing lures at the end of their tentacles," she said.

“This study also highlights the importance of public scientific collections in addressing long-standing scientific issues," Prof Allcock added.

"We supplemented the material we collected ourselves with samples from various museums including the Smithsonian Institution in the USA, the Biological Reference Collection of the Marine Science Institute in Spain and the Australian Museum, allowing us to have a truly comprehensive oversight of oceanic squids globally,“ she said.

The study was funded by the Irish Research Council through the Government of Ireland Postdoctoral Fellowship Awards.

Read the full study in Zoological Journal of the Linnean Society here Team

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Marine Wildlife Around Ireland One of the greatest memories of any day spent boating around the Irish coast is an encounter with marine wildlife.  It's a thrill for young and old to witness seabirds, seals, dolphins and whales right there in their own habitat. As boaters fortunate enough to have experienced it will testify even spotting a distant dorsal fin can be the highlight of any day afloat.  Was that a porpoise? Was it a whale? No matter how brief the glimpse it's a privilege to share the seas with Irish marine wildlife.

Thanks to the location of our beautiful little island, perched in the North Atlantic Ocean there appears to be no shortage of marine life to observe.

From whales to dolphins, seals, sharks and other ocean animals this page documents the most interesting accounts of marine wildlife around our shores. We're keen to receive your observations, your photos, links and youtube clips.

Boaters have a unique perspective and all those who go afloat, from inshore kayaking to offshore yacht racing that what they encounter can be of real value to specialist organisations such as the Irish Whale and Dolphin Group (IWDG) who compile a list of sightings and strandings. The IWDG knowledge base has increased over the past 21 years thanks in part at least to the observations of sailors, anglers, kayakers and boaters.

Thanks to the IWDG work we now know we share the seas with dozens of species who also call Ireland home. Here's the current list: Atlantic white-sided dolphin, beluga whale, blue whale, bottlenose dolphin, common dolphin, Cuvier's beaked whale, false killer whale, fin whale, Gervais' beaked whale, harbour porpoise, humpback whale, killer whale, minke whale, northern bottlenose whale, northern right whale, pilot whale, pygmy sperm whale, Risso's dolphin, sei whale, Sowerby's beaked whale, sperm whale, striped dolphin, True's beaked whale and white-beaked dolphin.

But as impressive as the species list is the IWDG believe there are still gaps in our knowledge. Next time you are out on the ocean waves keep a sharp look out!