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| Terrapotamon thungwa
Promdam, Yeesin & Ng. 2017
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Abstract
A new species of potamid crab of the genus Terrapotamon Ng, 1986, is described from karst forests in
Satun, Peninsular Thailand. Terrapotamon thungwa n. sp. has very long ambulatory legs and superficially resembles T. longitarsus, the only other long-legged species in the genus. They can easily be distinguished by life colouration,
carapace features, as well as structures of the epistome, male thoracic sternum, cheliped and male first gonopod.
Key words: Freshwater crab, new species, Potamidae, Peninsular Thailand, karst, caves, taxonomy
TAXONOMY
Family Potamidae Ortmann, 1896
Subfamily Potamiscinae Bott, 1970, sensu Yeo & Ng, 2004
Genus Terrapotamon Ng, 1986
Terrapotamon thungwa n. sp.
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| Terrapotamon thungwa n. sp., colour in life from Satun, Thailand. A–C, holotype male (44.6 × 35.0 mm) (ZRC 2016.0595). |
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| Terrapotamon thungwa n. sp., observed in the cave at Ban Namtok Than Plio, Amphoe Thung Wa, Satun, Thailand. A, paratype male (41.1 × 33.3 mm) (PSUZC-CRU-0072). |
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| Terrapotamon thungwa n. sp., observed in the cave at Ban Namtok Than Plio, Amphoe Thung Wa, Satun, Thailand. B, C, paratype female (29.4 × 23.8 mm) (PSUZC-CRU-0073). |
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| Terrapotamon thungwa n. sp., specimen observed in cave in Ban Namtok Than Plio, Amphoe Thung Wa, Satun, Thailand. |
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| Terrapotamon longitarsus Lheknim & Ng, 2016 paratype male (40.8 × 32.5 mm) (PSUZC 20150726-01.01), Satun, Thailand. |
Etymology. The name is derived from the type locality at
Amphoe Thung Wa. The name is used as a noun in apposition.
Remarks. The long ambulatory legs of T. thungwa n. sp. is a
character shared only by one other species of Terrapotamon,
T. longitarsus Lheknim & Ng, 2016, also from the Satun
area in Peninsular Thailand. It is surprising to find two
similar species occurring in the same area, but the differences
between the two species are very marked and leave no doubt
they are separate taxa. Terrapotamon thungwa can most
easily be separated in its bright red overall coloration in life
(Figs. 1, 8A) (purple in T. longitarsus; Fig. 6); ....
Habitat. All the specimens of Terrapotamon thungwa
were obtained from the karst landscape of Satun. From the
material collected, it would appear that the area and habitat
where T. thungwa occurs overlaps with T. longitarsus. Both
species were found inside and outside the caves as well as
in the karst forest. In the dark zone inside the cave, adults
of T. thungwa were observed climbing on the cave walls
(Fig. 8B, C), with a small specimen observed in a pool
on the cave floor (Fig. 9A, B). Up to five specimens have
been observed on the cave floor. Adult males of both two
species were observed in rock pools at the bottom of deep
crevices in the karst forest, while a small specimen of T.
longitarsus were seen at a sheltered rock pool near the cave
entrance (Fig. 9C, D). The crabs use these collected pools
to replenish their gill chambers.
Rueangrit Promdam, Pun Yeesin and Peter K. L. Ng. 2017. A Second New Species of Terrestrial Long-legged Terrapotamon Ng, 1986 (Crustacea: Brachyura: Potamidae) from Karst Forests in Peninsular Thailand. RAFFLES BULLETIN OF ZOOLOGY. 65; 404–415.
Vachira Lheknim and Peter K.L. Ng. 2016. A New Species of Long-legged Terrestrial Terrapotamon Ng, 1986 (Crustacea: Brachyura: Potamidae) from Limestone Formations in Satun, southern Thailand. Zootaxa. 4200(1); 143–152. DOI: 10.11646/zootaxa.4200.1.6 ResearchGate.net/publication/311004094_A_new_species_of_Terrapotamon_from_Satun_southern_Thailand
