Historical notes on various collectors of unidentified freshwater crabs (Crustacea: Decapoda: Brachyura) from the Malay Peninsula and Borneo, with descriptions of two new species of Isolapotamon Bott, 1968 Potamidae) Author Ng, Peter K. L. Author , Martyn E. Y. Low Author Clark, Author Paul F. text Raffles Bulletin of Zoology 2022 2022-12-12 70 550 571 journal article 10.26107/RBZ-2022-0031 2345-7600 13256876 633217F0-3D8F-478B-B300-5AABADEB3066 Fasciarma fasciatum ( Lanchester, 1900 ) Sesarma fasciata Lanchester, 1900: 758 , pl. 47, fig. 12. Sesarma ( Chiromantes ) siamense Rathbun, 1909: 109 . Material examined. 1 ovig. female, Siam ( NHM 2022.155), coll. Capt. S.S. Flower. ZRC material – 6 males , 7 females ( ZRC 2012.368 ), Kranji Nature Trail , northern Singapore , coll. P.K.L. Ng , 16 November 2011 ; 3 males , 4 females ( ZRC 1999.0568 ), Pandan Besar , Bako National Park , Sarawak , Malaysia , coll. P.K.L. Ng et al., 28 June 1994 ; 1 male , 1 female ( ZRC 2020.0367 ), Tanjung Delima , Bako National Park , Sarawak , Malaysia , coll. P.K.L. Ng et al., 30 June 1994 ; 4 males , 3 females ( ZRC 2000.1667 ), estuary near University of Sabah , Kota Kinabalu , Sabah , Malaysia , coll. P.K.L. Ng & C.D. Schubart , 22 June 2000 . Remarks. The NHM female agrees well with what has been redescribed by Shahdadi & Schubart (2017) . Smaller adult specimens tend to have the carapace relatively slightly wider and the lateral teeth more pronounced (e.g., ZRC 1999.0568), as is the case for the present specimen in NHM. Fasciarma fasciatum , common in back mangroves, was described from Singapore but has since been reported from Peninsular Malaysia , eastern Thailand , northern Borneo (Labuan), southern China and Hong Kong (cf., Shahdadi & Schubart, 2017: 541 ). As discussed under the remarks for Sayamia (see above), the provenance of the present specimen is uncertain and its supposed origins, Thailand , must be treated with doubt.