How Coenobita lila is discovered and accepted as new species
2006
A land hermit crab enthusiast, Félix J. Wáng found Coenobita purpureus inhabit in Indonesia and named Indonesia/Kelomang Blueberry. Adult are in purple, burgundy, brown or greyish purple. There is black band on the lower surfaces of the eyestalks, no series of ridge (////) on upper outer surface of palm of left cheliped (Especially on the adult).
2010
Overseas land hermit crab enthusiast also think that they are Coenobita purpureus. I pointed out that Coenobita purpureus of Japan is different with Indonesia/Kelomang Blueberry in a forum (HCA , Hermit Crab Association). But Félix J. Wáng(Mokulele_Hawai’i) still believe that they are Coenobita purpureus, full content please see HCA.
I wrote an article (In Chinese) (Comment respond to Morphological and Molecular Evidence for a Stepwise Terrestrial Evolution and Species Delimitation on the Coenobita Phylogeny) and analyze that they may be a new species(Page 35-42) and concluded below points for comparison. ⇒ https://www.tonycoenobita.com/commentonspeciesdelimitationbytony_trad2020.pdf
From my study, this species may also inhabit in Singapore and Malaysia. Juvenile in very small size are in light orange.
I do not agree with Félix that they are Coenobita purpureus. Morphology is one of a marker in species delimitation. Besides above characteristics, I found a important evidence, the male coxae of 5th legs of this species is not same as Coenobita purpureus, right coxa is no produced into an elongate tube. So in my opinion, this may be a new species different from Coenobita purpureus. They are not real Coenobita purpureus. I think this species needs further investigation to proof if it is new species.
2015
In Singapore, information show that they are Coenobita violascens or Coenobita cavipes. But according to a seminar in Singapore at 29 Oct 2015, Dr Dwi Listyo Rahayu is now studying about this and got already the proof it is new species. The report will be published later.
2016
According to the report < new species of land hermit crab in the genus Coenobita Latreille, 1829 from Singapore, Malaysia and Indonesia, previously confused with C. cavipes Stimpson, 1858 (Crustacea: Decapoda: Anomura: Coenobitidae) > published on 29 June 2016, a new species Coenobita lila is described from Singapore and adjacent countries.
*Thank you this article credit me → Thanks are also due to (Tony Choi) for providing useful information
Common name
Indonesia/Kelomang Blueberry.
Size
Shield length can reach 19mm.
Distribution
Singapore, Indonesia, Malaysia.
Habitat
Upper intertidal to 100m inland from the beach, under grass beds or under stones during the day. Also found in reef, at the edge of mangroves and estuarine habitats.
Larval stages
Unknown.
Characteristics
Adult In general is violet, dark purple, purplish blue or brownish purple. Adult female is pale or light purple.
Shield transversely convex. Surface of shield with patch of dark purple or light brown anteriorly. Lateral surface slightly punctate, doral surface scattered with small and large tubercles.
Eyestalks Eyestalks are compressed in shape, with dark brown band on the lower surfaces of the eyestalks.
Antenna Antennal acicles are fused with the second segment of peduncle.
Flagellum of antennule (1st antennal) and antenna are brown.
Cheliped Left cheliped is bigger than right cheliped. No series of ridges (////) on upper outer surface of palm of left cheliped.
Upper margins of both cheliped with brush of setae.
Lower proximal part of palm of left cheliped angled, forming slightly oblique lobe-like projection, continued to slightly upright lower margin of fixed finger. Lower outer surface of palm covered with tubercles.
Walking legs Lateral surface of propodus of left 3rd walking leg slightly flattened.
Carpus and Merus with longitudinal light brown streak on surface of walking legs.
Both 2nd & 3rd walking legs covered dark brown granules.
Outer surface of propodus of left 3rd walking leg not separated from dorsal surface by a well-marked longitudinal crest(A).
Abdomen The abdomen is a little big long.
Male coxae of 5th legs Coxae of 5th legs thick, forming moderately long, calcified sexual tube, subtriangular, left tube slightly broader than right.
Juvenile Young male is pale or light purple. Small females in light purple, greenish white or yellowish green.
Remark
1. Adult Coenobita lila has been misidentified as Coenobita purpureus because of purple body colour.
According to < new species of land hermit crab in the genus Coenobita Latreille, 1829 from Singapore, Malaysia and Indonesia, previously confused with C. cavipes Stimpson, 1858 (Crustacea: Decapoda: Anomura: Coenobitidae) >, Coenobita purpureus is easily separated from Coenobita lila by the presence of ridges (////) on upper outer surface of palm of left cheliped and an asymmetrical sexual tube.
2. According to < new species of land hermit crab in the genus Coenobita Latreille, 1829 from Singapore, Malaysia and Indonesia, previously confused with C. cavipes Stimpson, 1858 (Crustacea: Decapoda: Anomura: Coenobitidae) >, Coenobita lila differs from Coenobita violascens in the absence of prominent longitudinal ridge separated the dorsal and lateral surfce of propodus of 3rd walking legs and in the slightly elongated, subtriangular shape of the male sexual tube.
The other different is to see the joint (red circle) between propodus and dactylus of 3rd walking leg.
Coenobita lila – with a concave ‘reverse L’
Coenobita violascens – WITHOUT a concave ‘reverse L’.
Dwi Listyo Rahayu, Hsi-Te Shih, Peter K. L. Ng, 2016. A new species of land hermit crab in the genus Coenobita Latreille, 1829 from Singapore, Malaysia and Indonesia, previously confused with C. cavipes Stimpson, 1858 (Crustacea: Decapoda: Anomura: Coenobitidae)