Abstract:

Thermosbaenaceans (Thermosbaenacea: Halosbaenidae) are crustaceans, widespread, and occur in various habitats, including oligohaline or anchialine caves, freshwater, thermal springs, or cold waters. Currently, four families, seven genera, and 45 species are recognized worldwide. During the observation in an isolated limestone of Tham Loko (Loko Cave), Khao Chiason District, Phatthalung Province, the Theosbaena loko n. sp. were found. Theosbaena is the only genus reported in the oriental region. There are only two known species, namely Theosbaena cambodjiana Cals amp; Boutin 1985 from Kampot province, southern Cambodia, and T. kiatwongchai Rogers amp; Sanoamuang 2016 discovered in a cave of Takhli district, Nakhon Sawan province, central Thailand. Theosbaena loko n. sp. is the third species recorded in the oriental region.A new species Theosbaena loko n. sp. is described from a limestone cave in Phatthalung province, southern Thailand. The new species differs from its congener by having a telson, 1.8 longer than its breadth, maxilla 1 palp distal segment 4 times longer than the proximal palpomere, and the maxillopodal exopod twice as long as its basal width. This micro shrimp is the third described species of the genus known from Thailand and the Oriental region. A key to the species is given and suggestions for the conservation status of the new species are discussed.

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