Distinguishing features

Female apterous; antennae 8-segmented, sensorium on III small, circular and lens-shaped but on IV often transversely oval; Head smaller than pronotum, vertex with pair of long ocellar setae; compound eyes with 10–12 facets. Pronotum trapezoidal, paired longitudinal sutures laterally, one pair of long posteroangular setae. Mesonotum, metanotum and tergites with no lines of sculpture. Tergite IX median setae shorter than sub-median pair; tergite X trichobothria smaller than spiracle on tergite VIII with axial seta short or even absent. Sternite VII posterior margin with pair of lobes each bearing two small setae near the base.
Male similar, but vertex developed as extensive pore plate; fore legs enlarged with pointed tubercle at inner apex of tibia; mesonotum, metanotum and tergites with several transverse lines of sculpture. 

Related species

The genus Merothrips currently comprises 20 species - 16 extant and four known only from fossils (ThripsWiki, 2023). Most of the species are from the Neotropics (Cavalleri et al., 2019), with two known only from India, and two found widely around the world. Of these two, females of M. brunneus are generally darker than those of M. floridensis, with more protuberant eyes each comprising 10–12 facets, and the sensorium on antennal segment III is small and circular. In M. brunneus the trichobothria on tergite X are unusually small, whereas they are absent in M. meridionalis from southern Brazil, a species previously misidentified as M. mirus that has been considered similar to M. brunneus (Cavalleri et al., 2019).

Biological data

Breeding on dead leaves and dead branches, and presumably fungus-feeding.

Distribution data

Newly discovered in Europe, with recent findings from East Sussex, in and around Hastings, and from Guernsey in the Channel Islands, this species has most likely been introduced accidentally by trade (Ulitzka et al. 2024). Originally described from New Zealand, it has been seen from eastern Australia, New Caledonia, and Costa Rica, and has been recorded from the Amsterdam and St Paul Islands in the southern Indian Ocean. However, the species possibly originated in South America (Cavalleri et al., 2019; Mound & Marullo, 1996).

Family name

MEROTHRIPIDAE

Species name

Merothrips brunneus Ward

Original name and synonyms

Merothrips brunneus Ward, 1969: 362

References

Cavalleri A, Lindner MF & O’Donnell CA (2019) Merothrips meridionalis sp.n. (Thysanoptera: Merothripidae), a new fungivorous species from subtropical South America. Zootaxa 4668 (2): 277–282.

Mound LA & Marullo R (1996) The Thrips of Central and South America: An Introduction. Memoirs on Entomology, International 6: 1–488.

Mound LA & O'Neill K (1974) Taxonomy of the Merothripidae, with ecological and phylogenetic considerations (Thysanoptera). Journal of Natural History 8: 481–509.

ThripsWiki (2023). ThripsWiki - providing information on the World's thrips. <http://thrips.info/wiki/Main_Page>

Ulitzka MR, Marquis AS & Binns D (2024) Topsy-turvy world – southern hemisphere thrips at home in the north (Insecta: Thysanoptera). Entomologist’s Monthly Magazine 160: 204–212.