Copelatus befasicus Taxonomic revision of the genus Copelatus of Madagascar (Coleoptera, Dytiscidae, Copelatinae): the non- erichsonii group species Ranarilalatiana, Tolotra Raveloson Ravaomanarivo, Lala Harivelo Bergsten, Johannes ZooKeys 2019 869 19 90 Y34D 246290f1-7f40-5991-8cab-1ef8a036b9d5 Guignot, 1956 Guignot 1956 Insecta Dytiscidae Copelatus CoL Animalia Copelatus befasicus Coleoptera 0 19 Arthropoda species befasicus   Copelatus befasicusGuignot, 1956: 79.  Type locality. Madagascar, Morondava, forest south of Befasy.  Type information from original description. based on an unknown number of female type specimens but holotype and paratypes are distinguished in introduction. Collected in January 1956 by R. Paulian.  Type material studied.  Toliara. Menabe: Morondava: -HT♀ (MNHN, "coll. IRSM"): // Data in NHRS | JLKB | 000030021 // Morondava | foretsud | de Befasy | I-56 R.P // Type [red label] // INSTITUT | SCIENTIFIQUE | MADAGASCAR // Guignot det., 1956 | Copelatus| befasicusn. sp. | Type // -2PT ♀ (MNHN, "coll. Guignot"): // Data in NHRS | JLKB | 000030300-1// Morondava | foretsud | de Befasy // I-56 R.P // Paratype [red label] // [female symbol] //  Additional material studied.  Mahajanga. Melaky: Morafenobe: -1♀ (NHRS): // NHRS-JLKB | 000010860 (JB204) // Madagascar: Mahajanga: Melaky | Btw. Morafenobe-Ambohijanahary| S18.19091; E045.19986, 290 m.a.o | 19.XII.2009 Water Net, Field# MAD09-74 | Leg: J. Bergsten, N. Joensson, T. | Ranarilalatiana, H.J. Randriamihaja //  Diagnosis. Similar to  C. insuetusand related species in habitus by being small, elongate, and subparalell, but  C. befasicusis distinguished from  C. insuetusand from all other Malagasy  Copelatusspecies by the presence of only five elytral striae, and without submarginal striae. In addition, the first stria is shortened, present only in the posterior third ( Fig. 10D).  Description. Body length 4.1-4.2 mm. Body shape elongate and subparallel, dorsal surface reddish brown with a lighter elytral base. Head and pronotum uniformly rufus brown. Head, pronotum and elytra with dense punctation. Elytra and pronotum covered with dense punctures and the whole dorsal surface with a microsculpture. Lateral sides of pronotum striolate with the widest striolate area in the posterior corners. Elytra light brown with a distinct testaceous band basally ( Fig. 10D). First elytral stria shortened and present only in posterior third. Second to fifth elytral stria starting more or less at base and all striae approaching the apex of elytron, but the second and fourth a little shorter. Submarginal striae absent. Appendages testaceous. Ventral side light brown. Metacoxa and abdominal ventrites punctate and striolate. Prosternal process rather short and medially raised, triangular in cross-section. Lateral parts of metaventrite medium broad. Metacoxal lines anteriorly diverging but rather weakly so, abbreviated well before metaventral margin. Antennae, palps and legs testaceous. Male: unknown.  Distribution. Known only from two localities in the western part of Madagascar, the deciduous forest south of Befasy, Morondava, and at one locality between Morafenobe and Beravina village ( Fig. 12D).  Habitat and ecology. Paulian collected the species in 1956 in the western dry deciduous forest south of Befasy, Morondava. We rediscovered the species in 2009, when we found one female specimen of  C. befasicusalso in the western part but a bit further north than the type locality, along the road between Morafenobe and Beravina village at an altitude of 290 m. This locality consisted of dry savannah with mixed wood and grassland ecosystem after deforestation. The habitat consisted of muddy/sandy residual pools with some dead leaves in a temporary stream after the rainy season. The dry deciduous forest ecosystem in western Madagascar has suffered immensely from deforestation and very little of this habitat remains ( Ganzhorn et al. 2001; Whitehurst et al. 2009). The species is rare and likely threatened due to the disappearance of western deciduous forests in Madagascar. That all four known specimens are females may suggest an uneven sex ratio as a test of equal sex ratio is marginally non-significant (p = 0.0625) if considered randomly picked from the population.  Comments. This is the only species in the  Copelatus longicornisgroup from Madagascar. The  longicornisspecies group currently contains 38 species distributed mainly in the Neotropical and Afrotropical regions but also with few species present in Japan, New Guinea, and Fiji Islands ( Nilsson and Hajek2018). The group as currently defined is certainly artificial from a phylogenetic perspective and the only character they have in common is the low number of elytral striae.