Tolkien was a taxonomist.

At least, he had thoughts like that of a taxonomist. A taxonomist is someone who thinks about taxa, about how to make sensible groups out of individuals, especially about what constitutes a species. Without taxonomy the world is just a place full of individuals and biology struggles to deal with understanding this sheer diversity. If we lump things together we can start to talk about hedgehogs and holly, beetles and bananas. We can ask questions about how things work. We can measure things. We can make sense of the world. Taxonomy is the necessary first step to understanding the living world around us.
Tolkien was a splitter. In the taxonomy world you tend to get people who are lumpers, who create big groups that have a lot of variation of traits within the group and that differ a lot from other closely related groups, and splitters, who tend to create small groups that possess similar traits and differ a little from other closely related groups. Tolkien couldn’t help himself. It wasn’t enough for him to create different species like dwarves, ents and orcs but he had to further divide them into subspecies.
“Before the crossing of the mountains the Hobbits had already become divided into three somewhat different breeds: Harfoots, Stoors, and Fallohides. The Harfoots were browner of skin, smaller, and shorter, and they were beardless and bootless; their hands and feet we’re neat and nimble; and they preferred highlands and hillsides. The Stoors were broader, heavier in build; their feet and hands were larger, and they preferred flat lands and riversides. The Fallohides were fairer of skin and also of hair, and they were taller and slimmer than the others, they were lovers of trees and woodlands.” (The Prologue, The Fellowship of the Ring)

Tolkien goes on to list other differences but he has already captured the essence of Hobbit taxonomy. He has noted physical (phenotype) differences. Identified behavioural differences. Listed habitat preferences and goes on to discuss their species distribution range. These are all of the sorts of things that taxonomists look for in their own species or, in this case, subspecies descriptions.
Tolkien has similar detail for elves (where we have races/subspecies of Eldar and Avan, the Noldor and Sindar and several more) as well as for the non-human races. Dragons were divided in to main species the cold-drakes (who used fangs and claw) and the Uruloki or fire-drakes (who had breath of flame). And on and on. In Tolkien’s mind, this taxonomy of Middle-earth helped to sort his creation out, from Muddle-earth to Middle-earth as it were. Taxonomy in the real world does exactly the same thing.
In the ‘real’ Middle-earth there are many taxonomic questions to be answered. New Zealand has a large biota and few scientists. Typically only half of most species groups are currently known and named. One such group is the damselflies. Damselflies are relatives of dragonflies and, like the Stoors, prefer flatlands and riversides.
One genus of damselflies in New Zealand is Xanthocnemis. Early research suggested, based on trait measurements, that there were several species of this genus in New Zealand, Xanthocnemis zealandica, Xanthocnemis sobrina, Xanthocnemis tuanuii and Xanthocnemis sinclari. Recent research has suggested that X. zealandica and X. sinclari are actually the same species. Milen Marinov and colleagues from around New Zealand looked at the situation for X. zealandica (found around most of New Zealand), X. sobrina (found along water courses in northern Kauri forests) and X. tuanuii (found on the Chatham Islands). The team collected specimens from throughout the species ranges and measured their body parts as well as examining their genetic similarity.

Milen and the team have published their results in the journal Zootaxa. They found that X. tuanui was different to the mainland species and was confirmed to be an endemic species (found nowhere else) of the Chatham Islands. Xanthocnemis sobrina was found to differ in a number of physical traits compared to X. zealandica. This appeared to support that the northern damselflies are a different species. However, the genes told a different story. The genes from individuals of X. zealandica and X. sobrina were found to be indistinguishable. This implied that the populations were able to interbreed freely, that they had not been separated in the past, and that any physical difference must be a result of influences of the local environment.
A closer examination of the physical traits suggested that they might be a result of scale. X. sobrina individuals are larger and the traits are all relatively larger. Milen and the team were left to conclude that X. sobrina is not actually a different species but rather is just a bunch of populations of X. zealandica at the northern end of this species’s range. The damselfly genus Xanthocnemis appears to only have two species in New Zealand.

Does it really matter? Tolkien taught me the value of naming groups. Once something has a name it can have a history, it can be cared about, it matters. From a conservation point of view losing a ‘false’ species is helpful. Previously we had an endangered and range restricted species of damselfly that needed resources spent on it to help its survival. This research suggests that we actually have a widespread species that requires far less active management. Those resources can be used productively elsewhere.
As I have said before, Tolkien prepared me to be an evolutionary biologist. He showed me the value of naming species, subspecies and groups. He also showed me that species naturally contain a lot of variation and that the history of these species drives a lot of these differences. All in all, Tolkien is essential reading for developing a young biologist.