Diversity of sessile rotifers (Gnesiotrocha, Monogononta, Rotifera) in Thale Noi Lake, Thailand Author Meksuwan, Phuripong Author Pholpunthin, Pornsilp Author Segers, Hendrik text Zootaxa 2011 2997 1 18 journal article 10.5281/zenodo.207999 b2e49ad5-de16-41c0-ad9d-1fa53dc0addf 1175-5326 207999 Ptygura thalenoiensis new species ( Figs 6–7 ) Synonym: Ptygura sp. near linguata Edmondson, 1939 after Segers et al ., 2011 ( Figs 9 –12) Type material. Holotype female (PSUZC-PK5PM001-01) was deposited in Princess Maha Chakri Sirindhorn Natural History Museum, Prince of Songkla University, Songkhla, Thailand ; two paratype females deposited in RBINS , BRUSSELS , GI 31863 RIR 202-203. Type locality. Thale Noi Lake, Phatthalung province, Thailand : 7o 45’ 44’’ N to 7o 48’ 26’’ N and longitude 100o 7’ 31’’ E to 100o 11’ 12’’ E , June 2009 through April 2010 . Differential diagnosis. The new species belongs to a group of congeners that are diagnosed by having elongate lateral antenna. Amongst those, P. thalenoiensis n. sp. is distinguished by the presence of a pair of apical hooks in addition to a tongue-shaped projection in between those, and of an autapomorphic ciliated projection in its mouth region. Description. Body well separated from the elongate, retractible foot, terminating in a medium to long peduncle. Corona elliptic, twice as wide as trunk; dorsal gap minute; corona supported by relatively strong rods. Buccal area with distinct short and cylindrical projection bearing a group of elongate cilia terminally. Neck region distinct, with two sharp dorsal hooks lateral to a tongue-shaped projection, this projection protruding beyond, but less rigid than the hooks. Lateral antenna long and slender. Tube gelatinous, containing fine perpendicular lines of material radiating from the inside of the tube. Fine layers radiated from inner sheath; light to medium brown; inner sheath obvious, quite parallel along tube to. Male unkown. Trophi nearly symmetrical, malleoramate. Unci left and right 17 teeth, these weakly differentiated into a proximal group containing 3 slightly stronger teeth and a distal group of weaker teeth (3–4 teeth); second tooth in the left group of proximal teeth small. Teeth in the distal group interdigitating with rami scleropilli (visible most in the left group). Fulcrum short, with a weakly developed basal plate. Measurements. Females total length ca. 700 µm. Trunk length ca. 150–230 µm, width ca. 40–50 µm. Foot length ca. 200–450 µm. Foot stalk length ca. 15–60 µm. Corona height ca. 90 µm, width ca. 140 µm, width/height ratio ca. 1.6. Lateral antenna length ca. 80 µm. Etymology. The species name thalenoiensis is an adjective, derived from the type locality of the species. Distribution. In addition to the type locality, the new species is known from Cambodia (sub. Ptygura cf. linguata, Segers et al., 2011 ). Apparently, it is endemic to Southeast Asia.