Viola Land hermit Crabs, Coenobita violascens, Phuket shores, Andaman Sea.
The land hermit crab, Coenobita violascens, gets its specific name, violescens, from the latin word viola meaning the colour violet, and the flower violets. They are quite large hermit crabs, full growth they can be over 80mm long,
Coenobita violascens, like other Coenobitidae land hermits, is pretty omnivorous in its diet, but is primarily a scavenger. It patrols the upper reaches of beaches (technically, the supralittoral) and mangrove areas. It’s known to occur from the shores of East Africa (Tanzania) through the Nicobar Islands in the Andaman Sea, Thailand, Cambodia, as far east as the Philippines and Southern Japan. DNA analysis has recently identified several new species of Coenobita, so it’s possible this wide-ranging species may be split at some point.
Like other Coenobitidae hermit crabs, mating occurs on land, the male releasing a spermatophore (sperm capsule) as the female releases eggs. The reproductive cycle of Coenobita crabs is thought to be broadly similar. The developing eggs are held by the female in their pleopods, then later carried down to the sea’s edge where she will release them. The developing larvae drift as plankton, moulting through several zoeal stages. The megalopa is the final larval stage; they then moult into a juvenile crab, which will then search the seabed for a suitable shell before emerging from the sea. Juvenile viola hermit crabs are known to prefer mangrove areas. Research in Japan (Fujikawa et al, 2018) found that settlement of megalopa on the seabed and searching for shells by new juveniles was accelerated by low salinity water. This makes sense as river outflows would likely indicate the presence of mangroves onshore.
I have a number of short clips, 30 – 60 seconds, of Coenobita violascens land hermit crabs available for licensing. Example below.
Coenobita violascens land hermit crab in a murex shell on intertidal sand flats, Thailand. Available in 4k and HD resolution.
The above 60 second clips is available as HD or 4K (4096×2160). These versions are uploads encoded using H.264 codec, 50mbps. Also available encoded w ProRes 422, 478mbps (file size 2.4GB).
These hermit crab images are new, so I’m still going through editing and uploading. In the coming days and weeks I’ll upload more Coenovita violascens images. I’ll also be uploading or linking to video footage (available as 4K). So check back again and there should be more info about these guy, plus more images.
These images are available to license by contacting me directly. For video footage please also email me directly.
You can follow me on Facebook at Colin Munro Photography and Instagram at @ColinMunroPhoto and X (twitter) at @colinmunrophoto
You can find my articles on Substack here
You can also read (and subscribe to if you like) my Blog at colinmunrophotography.com/blog .
References
Emigration behaviour, moulting and survival during the sea-to-land transition of land hermit crabs Coenobita violascens and Coenobita rugosus under laboratory conditions: Effects of salinity and riverine odours, Biogeography, 2018, Volume 20, Pages 111-121, Released on J-STAGE September 16, 2020, Online ISSN 1880-8085, Print ISSN 1345-0662, https://doi.org/10.11358/biogeo.20.111, https://www.jstage.jst.go.jp/article/biogeo/20/0/20_111/_article/-char/en