The identity of Coenobita longitarsis, described in
1902, remained a mystery for over 120 years until its confirmation.
Morphologically, this species has a slender and elongated body and
appendages, making it easily distinguishable from other species. It
primarily resides deep within island forests, often located 3-10
kilometers from the coast, and inhabits land snail shells, which may
explain its infrequent discovery. Its distribution includes Indonesia,
Papua New Guinea, the Philippines, and Guam.
Another species, C. pseudorugosus,
described in 1988 with a type locality in Cebu, Philippines, also faced
uncertainty regarding its accuracy after its publication. After
examining specimens from Cebu and Indonesia, molecular evidence
supported the confirmation of its status and distribution in this
study. It closely resembles C.
rugosus morphologically but can still be differentiated by male
reproductive organs and the characters of the left third pereiopod.
However, there is no direct phylogenetic relationship between the two
species. Its distribution is in the Philippines and Indonesia. Due to
the lack of specimens, this study could not confirm reported records
from the Indian Ocean.