Indonesian species of Dilatognathus Kluge 2012 (Ephemeroptera, Leptophlebiidae, Choroterpes s. l.) and species-specific sexual dimorphism in development of maxilla Author Kluge, Nikita J. text Zootaxa 2014 3786 1 journal volume 46025 10.11646/zootaxa.3786.1.2 ef8a0c66-3103-4a40-8302-0a1a4055811a 1175-5326 231537 09DC7D2C-B15B-4DC8-9D89-FDC0E97D2776 Choroterpes ( Dilatognathus ) nigella (Kang & Yang 1994) = Choroterpides nigella Kang & Yang 1994 = Dilatognathus/g(1) sp.3: Kluge 2012 Material. THAILAND : province Mae Hong Son, river Namlang near Lot Cave, 12.I.1998 , coll. V. Ivanov: 17 larvae ; province Muang Pai, river Pai, 11.I.1998 , coll. V. Ivanov: 7 larvae ; SW Chiang Mai, Doi-Ithanon, river Klang, 17.I.1998 , coll. Grigorenko: 1 larva; national park Kaeng Krachan, river Pchetchabun, 26.II.2006 , coll. M. Chertoprud: 4 larvae . CHINA , HAINAN, Miao-Li, 19.XII.1957 , coll. N. Andrianova: 2 larvae (one of them with developing cuticle of next instar). Additional characteristics. Larva. Described by Kang & Yang (1994). Differs from all other species of Dilatognathus by shape of labrum, whose median incision is deep, semicircular and bordered by sharp semicircular impression on dorsal surface (Kang & Yang 1994: Fig. 3A). Structure of maxillary apex in penultimolarva is the same as in ultimolarva: with long tusk bearing 3 vestiges of ventral pectinate setae, without ventro-apical flange and without dentiseta. Imago. Unknown. Egg. Described by Kang & Yang (1994). Dimension. Length of ultimolarva 6–10 mm . Distribution . Indochina Peninsula ( Thailand ), Hainan and Taiwan Islands. Discussion. Kang & Yang (1994) described Choroterpides nigella based on larvae and eggs. They did not compare Ch. nigella with Ch. minor . As characters distinguishing Ch. nigella from Ch. major , only two ones are named: (1) transversal curved row of long setae on labrum and (2) tooth-like maxillary tusk with three comb-like setae at its base. Actually, both characters are present in all Dilatognathus , including Ch . ( D .) major (Ulmer 1939: Figs 262, 265).