Here's why it's complicated:
* Species vs. Subspecies: There are around 1,500 species of hermit crabs in the world, but only about 15 are considered true land hermit crabs. Within these species, there are often many subspecies, making the total number of distinct types even more difficult to pin down.
* Variable Morphology: Hermit crabs, particularly land-dwelling ones, show a lot of variability within species. This means there's a lot of overlap in their appearances, making it hard to tell them apart.
* Continuous Variation: Land hermit crabs are constantly evolving and changing. This means that over time, new types emerge, and existing ones may become extinct.
Therefore, while we can't provide a definitive number, there are roughly 15 species of land hermit crabs, and likely many more subspecies and variations within those species.