Background Thermosbaenaceans are subterranean crustaceans, widespread and occur in freshwater, oligohaline or anchialine caves or thermal springs. Currently, four families, seven genera,and 45 species are recognised worldwide. During our studies of the isolated karst, Tham Loko (Loko Cave) in Khao Chiason District, Phatthalung Province, we found an undescribed thermosbanacean species in the genus Theosbaena. Theosbaena is the only genus reported from freshwater in the Oriental Region. Previously, there were only two known species, Theosbaena cambodjiana Cals & Boutin, 1985 from Kampot Province, southern Cambodia and Khon Kaen, Thailand and T. kiatwongchai Rogers & Sanoamuang, 2016 discovered in a cave of Takhli District, Nakhon Sawan, central Thailand. Our new species is the third species recorded in the Oriental Region. New information Theosbaena loko sp. n. differs from its congeners by having a telson 1.8x longer than its breadth, maxilla 1 palp distal segment 4x longer than the proximal palpomere and the maxillopodal exopod twice as long as its basal width. This microshrimp is the third described species of the genus. A key to the species is given and suggestions for the conservation status of the new species are discussed.

中文翻译：

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Theosbaena loko sp。n. 来自泰国南部的一种新的stygobiotic微虾（Thermosbaenacea：Halosbaenidae）

背景 Thermosbaenaceans 是地下甲壳类动物，分布广泛并出现在淡水、寡盐或锚链洞穴或温泉中。目前，全世界公认有4科7属45种。在我们对博他仑府考恰松县孤立的喀斯特地貌 Tham Loko (Loko Cave) 进行研究期间，我们在 Theosbaena 属中发现了一种未描述的thermosbanacean 物种。Theosbaena 是东方地区淡水中唯一报道的属。此前，只有两种已知物种，1985 年来自柬埔寨南部贡布省和泰国孔敬的 Theosbaena cambodjiana Cals & Boutin 和 2016 年在泰国中部那空沙旺 Takhli 区的一个洞穴中发现的 T. kiatwongchai Rogers & Sanoamuang。我们的新物种是东方地区记录的第三个物种。新信息 Theosbaena loko sp。n. 与同类的不同之处在于它的尾节比其宽度长 1.8 倍，上颌骨 1 触须远端节段比近端掌节长 4 倍，上颌足外足节长是其基部宽度的两倍。这种微型虾是该属的第三个被描述的物种。给出了该物种的关键，并讨论了对新物种保护状况的建议。