From Mexico down to Chile, the coastline stretches for thousands of miles, and somewhere along it is supposed to be the Pacific guitarfish ( Pseudobatos planiceps ). At least, that is what historical records have told us. But maps are only as good as the information behind them and when researchers went back through the records for this poorly understood ray, they found that many of the historical reports were tangled up in what can only be described as taxonomic confusion, making it difficult to know whether the animals identified as Pacific guitarfish were actually P. planiceps .

After compiling verified records and using a species distribution model to estimate where the species can occur, researchers found a much narrower range for this species ; rather than ranging from Mexico to Chile, the Pacific guitarfish appears to be restricted to southern Ecuador, the Galápagos, Peru and northern Chile with no convincing evidence supporting its presence in Central America or northern South America. This sounds like a technical correction to a map, but for a marine species, the size of its geographic range can fundamentally change how we think about its conservation status. A species spread across thousands of miles of coastline may have many opportunities to find suitable habitat and reproduce, but a species confined to a much smaller region has fewer options when things go wrong.

And things can go wrong quite easily for guitarfishes.

Despite their name, guitarfishes are not guitars and they are not sharks. They are rays, belonging to the same broader group of cartilaginous fishes as sharks and skates. Their bodies combine features that make them look almost like a shark with a flattened ray-like front end. They spend much of their lives close to the seafloor, where their shape and coloration can help them blend into their surroundings. And that lifestyle puts them in an unfortunate position when fishing activity overlaps with their habitat. The problem is that a fishing net does not care whether a species is the intended catch — bottom-associated rays can be caught incidentally in fisheries targeting other species, particularly where trawling or other forms of intensive fishing occur. A guitarfish may not be the animal a fisher intended to catch, but it can (and does) still end up on deck.

For a species with a genuinely broad distribution, populations in one region might potentially be buffered by animals elsewhere. But if P. planiceps is actually restricted to southern Ecuador, the Galápagos, Peru and northern Chile, the situation looks very different. The researchers point to significant fishing pressure and a lack of species-specific management as reasons for major concern. If the Pacific guitarfish is being caught across much of its actual range without targeted protection, its populations could be declining without us fully appreciating the scale of the problem.

Which is why correctly identifying a species is foundational to conservation; if several similar-looking animals have historically been grouped together under one name, records can make a species appear more widespread and abundant than it really is. This (skewed) distribution map can then give managers a false sense of security, with is being easy to assume that the animal has plenty of room to move, reproduce and recover from local declines. Distribution modelling can combine verified occurrence records with environmental conditions to estimate where suitable habitat is likely to exist. While it does not replace field observations, it can help reveal patterns that would otherwise be difficult to see. And in this case, the model supports the idea that the Pacific guitarfish has a much more restricted distribution than historical accounts suggested. So what does that mean for the species’ future? At minimum, it means its conservation status deserves another look. A risk assessment based on an inflated geographic range could underestimate how vulnerable the species actually is.

The ocean is often described as vast, and it is. But vastness does not automatically make marine animals safe. So how much time do we have to protect this animal?