Key to the known species of Flavalona gen. nov.

1. Distal angle of postabdomen obtuse, with clearly defined tip ……………………………………… …………………………………………… F. weltneri (Keilhack, 1905) comb. nov.; West Palearctic – Distal angle of postabdomen acute or with broadly rounded apex …………………………………2

2. Lateral head pores long, length over 0.5 IP. Distal angle of postabdomen acute ………………3 – Lateral head pores short, length about less than 0.5 IP. Distal angle of postabdomen rounded…7

3. Two major head pores ……………………………………………………………………………… …………………… F. setigera (Brehm, 1931) comb. nov.; Australia and New Zealand, Neotropic – Three major head pores ……………………………………………………………………………4

4. Lateral head pore pockets deep, rounded, depth ca 1.5–2 lateral pore length …………………5 – Lateral head pore pockets shallow, semicircular, depth ca 1/2–1/3 pore length …………………6

5. Limb V strongly bilobed ……………………… F. costata (Sars, 1962) s.l. comb. nov.; Holarctic – Limb V only slightly bilobed ……………………………………………………… F. margipluma (Sousa, Santos, Güntzel, Diniz, de Melo Junior & Elmoor-Loureiro, 2015) comb. nov.; Neotropics

6. Valve sculpture composed of thin longitudinal striae or hexagons ………………………………… …………………………………………………… F. cheni (Sinev, 1999) comb. nov.; Indo-Malaya

– Valve sculpture composed of dense, broad longitudinal ridges …………………………………… ………………………………… F. natalensis (Sinev, 2008) comb. nov.; mountains of South Africa

7. Anterior margin of labrum with one or two denticles ……………………………………………… …………………………………………………… F. bicolor (Frey, 1965) comb. nov.; East Nearctic – Anterior margin of labrum without denticles ………………………………………………………8

8. Length of adult female up to 0.7 mm. Seta 6 of exopodite III about 2/3 lengths of seta 3 ……… …………… F. hudeci (Sinev, 1999) comb. nov.; Neotropics (syn. Alona rusticoides Hudec, 1998) – Length of adult female not exceeding 0.52 mm. Seta 6 of exopodite III almost as long as seta 3 …9

9. Lateral head pores dot-like with rounded pockets, widths of pockets over two lengths of pore …… ………… F. sphagnophila (Van Damme & Eggermont, 2011) comb. nov.; Mountains of East Africa – Lateral head pores transverse with semicircular pockets …………………………………………10

10. Central major head pore located closer to posterior one. Exopodite V strongly bilobed. Epipodites IV–V with finger-like processes longer than epipodite itself ……………………… ……………………………………… F. iheringula (Kotov & Sinev, 2004) comb. nov.; Neotropics

– Central major head pore located halfway between anterior and posterior pores. Exopodite V not divided into two lobes. Epipodites IV–V without processes ……………………………………… …………………………………………………… F. rustica (Scott, 1901) s.l. comb. nov.; Holarctic