Thrypticus Gerstäcker, 1864

Pollet, Marc, Leponce, Maurice, Pascal, Olivier, Touroult, Julien & Calster, Hans Van, 2018, Dipterological survey in Mitaraka Massif (French Guiana) reveals megadiverse dolichopodid fauna with an unprecedented species richness in Paraclius Loew, 1864 (Diptera: Dolichopodidae), Zoosystema 40 (21), pp. 471-491 : 488

Genus Thrypticus Gerstäcker, 1864

( Fig. 15C )

DIVERSITY. — 9 species (1.1-2.1 mm).

MORPHOLOGY, ECOLOGY AND DISTRIBUTION

As mentioned before, larval stages of this genus of minute to rather small species live as leafminers in plants, while adult flies are most often found in dense herb vegetation. Nearly all specimens were retrieved from samples collected by SLAMs and the 6 m large Malaise traps. Thrypticus was recorded from only seven sites and the fair numbers at two of them are entirely due to the use of the Malaise trap.

NEW GENERA

Four new genera were also discovered at Mitaraka, three of which were previously known to MP from species from several Central and South American countries, and are currently in the process of description. Species GF-001 of the Achalcinae new genus ( Fig. 15D ) belongs to a megadiverse exclusively Neotropical lineage that is most speciose at higher altitudes (e.g. Costa Rica) ( Pollet 2005). In tropical lowland rainforests, only a few species seem to occur. Contrary to most other Dolichopodidae but characteristic for this genus are the pale body colour, the specific colour pattern on the mesonotal dorsum, and the postpedicel with an anterior and posterior face that feature different colours. This genus was encountered at half of the Mitaraka sampling sites, and – contrary to almost all other Dolichopodidae – was most abundant on the slopes and hill tops, and in the drier palm swamps; it was entirely lacking from the rocky outcrops. A monograph on this lineage is being prepared by MP.

The new genus in Sciapodinae with three species found at Mitaraka has been recognized for over 10 years by MP and Dan Bickel (Australian Museum Sydney, Australia) who will dedicate a separate paper on this genus and the near 20 new species thus far discovered in Central and South America. Compared to most other Sciapodinae , this genus includes rather small and extremely slender species (wing size approx. 3 mm). Males have an extremely elongated fore tarsus.

Two new Mitaraka species were assigned to a new genus and possibly a new subfamily. MP has previously detected other species of the same lineage in Ecuador, Nicaragua, Costa Rica and Colombia. One of the two Mitaraka species was represented by females only; the male of the other species ( Fig. 15E ) features distinct MSSCs in fore and mid leg. Sixteen of the 20 specimens were collected with the 6 m long Malaise trap over the Alama River. This species group will further be treated in a separate paper.

The fourth new genus ( Fig. 15F ) belongs in Peloropeodinae and represents a taxon that has not been collected before, and is, at present, only known from Mitaraka. Five different species were recorded, and over 4/5 of the 84 specimens were retrieved from FITs and the 6 m Malaise trap. Ten specimens were collected near the river Alama where they were found both on sandy banks and on low vegetation hanging over the stream. Overall, most specimens were collected near the drop zone and on the river bank, although one species was only found on ‘savane roche 2’. A separate paper will be dedicated to the description of this genus.

Figures

FIG. 15. — Photos of selected Mitaraka Dolichopodidae: A, Medetera sp. GF-005, ♂; B, Tachytrechus sp. GF-005, ♂; C, Thrypticus sp. GF-004, ♂; D, species sp. GF-001 of Achalcinae new genus,♂; E, species sp. GF-001 of incertae sedis, ♂; F, species sp. GF-002 of Peloropeodinae new genus,♂. Photos: Florence Trus, except for E, Camille Locatelli.