Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 70. (Budapest 1978)

Kovalev, V. G.: Mongolian species of the Platypalpus albiseta-group (Diptera, Empididae)

ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus 70. Budapest 1978. Mongolian Species of the Platypalpus albiseta-Group (Diptera, Empididae)* by V. G. KovALEV, Moscow Abstract — Discussion of the species of albiseta-group of the genus Platypalpus McQ. from Mongolia is given. Four new species are described: Platypalpus argenticapillatus sp. n., P. bipunctatus sp. n., P. kaszabi sp. n., P. leucarista sp. n. With 17 figures. The species of the genus Platypalpus MCQ. close to P. albiseta PANZ. were placed into a separate group by COLLIN (1961). The species of this group may be separated from all the other species of Platypalpus by the combination of the two following features: ( 1 ) arista white, long, and (2) mid tibiae apically with a very small (much shorter than width of tibia) rim-like projection. The Platypalpus albiseta-group may be characterized as follows: Head small and globular. Frons and especially face unusually narrow, and eyes practically touching below antennae. One pair of convergent vti bristles (no divergent vte). Clypeus shining, bare. Antennái segment 1 fairly distinct. Arista white, long and thickened by dense white pubescence. Proboscis slender, shorter than half height of head. Palpi very small. — Thorax with only slightly developed prothorax; humeral calli small and flattened. Humeral bristle absent. Wings long and broad. Ta opposite or a little behind front angle of bp but tp long and very oblique, thus bp much larger than ba. Cu

2 very recurrent. •— Legs long. Fore femora thickened about base, apically slender. Mid femora with a posteroventral row of erect bristles or bristly hairs in addition to two rows of short black spines beneath. Mid tibiae apically with a very small (much shorter than width of tibia) projection or without any projection. — Male abdominal segments 7 and 8 completely hidden within preceding segment. Periandrial lamellae with distinct appendages. The species of the P. albiseta-group represent the very primitive forms of Platypalpus (KOVALEV 1969, 1974; CHVÁLA 1973, 1975). The large number of plesiomorphic features of this group proves that it existed already in the Cretaceous period; P. albiseta-group is like to be rich in species in the Paleogene. Most of the recent species are spread in subtropical regions. The European species may be found mainly in shaded and humid forest biotopes with predominantly broad-leaved trees. According to the data of the labels, the Mongolian species were found on intrazonal waterside shrubby and grassy vegetation. Altogether five or six species of the P. albiseta-group have been found in Mongolia. Four species are described here as new to science. It is significant, that at least four species of these thermophilous and hygrophilous insects were taken in southern and southwestern Mongolia. The species of the P. albiseta-group may be regarded in these regions as relicts of the fauna of forest oases around enormous lakes on the background of ancient savanna landscapes that were characteristic of Central Asia from the Cretaceous to Paleogene times which were gradually replaced by the deserts (EMELYANOV 1972). At least two of the Mongolian species (P. bipunctatus sp. n. and P. kaszabi sp. n.) more closely resemble some Oriental species than Palaearctic ones, therefore any later dispersal of this group from the north accompanied with a more humid climate and an expansion of forests during the Pleistocene is next to impossible. Under the present conditions of the Gobi desert this hygrophilous group can persist only in refuges, on intrazonal vegetation near springs and small lakes. •Ergebnisse der zoologischen Forschungen von DR. Z. KASZAB in der Mongolei, Nr. 423.