New Genera and Species of the Family Baetidae from West-Malaysia (River Gombak) (Insecta: Ephemeroptera) By Ingrid Müller-Liebenau Max-Planck-Institut für Limnologie, Plön Abt. Allgemeine Limnologie Abstract The nymphs of 15 new species of Baetidae from the River Gombak, West-Malaysia are described; characteristics are ülustrated. Thirteenof the species belongto thegenus Baetis, and two form monotypicgenera. Someof the Bae-tis species are morphologically similar to European species groups. Six of the thirteen Baetis species have a number of morphological characteristics in common vi^ith the four species of the European atrebatinus group and with the North American propinquus group. To distinguish the Malaysian species geographically from the European atre-batinus group and the North American propinquus group they are placed in the newly proposed Oriental molawi-nensis group (p. 274). The new Genus No. 1 sp. 1 appears to be related to the genus complex Proc/oeo« Bengsts-son-Centroptilum Eaton, whereas, Genus No. 2 sp. 1 appears close to the genus Centroptella Braasch & Soldän (1980). Longitudinaldistribution of the Baetidae in the River Gombak is given. The reiationships of the newly des-cribed species to known species groups are discussed and a key is given for the nymphs ot the 13 Baetis species treated in this paper. Introduction The beatid species described here were collected by Dr. J. E. Bishop during his comprehensive inve-stigation of a small Malaysian River, Sungai Gombak (Sungai = River), during 1969-1971 (Bishop 1973). Nymphs of 15 new^ species, included in three genera of Baetidae are described: 13 of the genus Baetis and one species each of two new genera. Some of the Baetis species show a close relationship to European and North American species groups of this genus. The new Genus No. 1 sp. 1 appears most closely related to the genus Centroptilum Eaton and Gen. No. 2 sp. 1 shows a number of morphologi-cal characteristics similar to the genus Centroptella Braasch & Soldän (1980). -From the same material a new genus and species, Raptobaetopus orientalis, was previously described (Müller-Liebenau 1978a, 1978b, 1980a). Two more species of known genera are also described in advance, viz. Platyhaetis hishopi (Müller-Liebenau 1980c) and Pseudocloeon verum (Müller-Liebenau 1981). According to the Catalogue of the Ephemeroptera of the Indian Subregion of the Oriental Region published by Hubbard & Peters in 1978, no species of the genera Baetis or Pseudocloeon were known from the Malayan Peninsula. According to that catalogue the distribution of Cloeon bicolor Kimmins (cT, $)and C. kimminsi Hubbard (2) in Malaysia is doubtful. Cloeon marginale Hagen (2) occursin the neighbouringislandsof Java and Sumatra and Procloeon bimaculatum Eaton (cf, $) in Java, Suma-tra and Thailand. Procloeon harveyi Kimmins (cf, 5) is known from Thailand and Malaysia. From these species either both male and female or only the female is known, no nymphs are described. 253
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