Key to the species of Ptilomerinae (Hemiptera: Heteroptera: Gerridae) of Thailand and review of the fauna of the Tennaserim Mountain Range Author Raruanysong, Sajeemat Author Vitheepradit, Akekawat Author Sites, Robert W. text Zootaxa 2014 3852 1 101 117 journal article 10.11646/zootaxa.3852.1.4 527bebc8-3c9d-4353-b991-c92a913ee7dd 1175-5326 230500 D0876B07-5E29-4D4F-BFB4-968CFBA5BCE1 Ptilomera tennaserim Vitheepradit & Sites Figs. 20, 21 , 34, 35 Ptilomera tennaserim Vitheepradit & Sites 2007 : Ann. Entomol. Soc. Am. 144–145. Diagnosis. Ptilomera tennaserim males can be recognized by the pygophore with a narrowly digitate apical projection ( Fig. 21 ) and females by abdominal segment VII reflexed upward from segment VI at a 75º angle ( Fig. 35 ). More specifically, males of P. tennaserim can be distinguished by the median lobe of the proctiger surpassing the posterior tips of the lateral wings of the pygophore ( Fig. 20 ), whereas the median lobe is more or less even with the posterior tips of the lateral wings in P . tigrina ( Fig. 22 ). Males of P. tennaserim can be distinguished by the pygophore with a digitate apex ( Fig. 21 ), which is broadly-rounded in P. j a r i y ae ( Fig. 17 ). Females of P. tennaserim can be distinguished by a well-developed ventrolateral lobe of abdominal segment VII ( Fig. 35 ) which is obsolescent in P. j a r i y a e ( Fig. 31 ), and by connexival spines that are strongly curved and crossing ( Fig. 34 ), whereas they are straight and convergent in P. tigrina ( Fig. 36 ). Discussion. This species was previously found in a shaded, gravel-bottomed stream which flowed from the mountains into a reservoir in the Tennaserim Range in Kanchanaburi Province ( Vitheepradit & Sites 2007 ). Although collecting during the present intensive survey was conducted repeatedly at the type locality and adjacent streams, additional specimens of this species were not collected. This may indicate the rarity of this species in the Thai fauna. Material examined. THAILAND : Kanchanaburi Province: Amphur Sangkhla Buri, Heuy Li Jia, 15º04'N 98º33'E , 169 m , 26-V-2004 , Vitheepradit and Prommi, L-718 ( 1 male , 2 females ); same locality, 12-V-2003 , AV, Prommi and Ferro, L-526 ( 1 female ).