Ovalona

Sinev, Artem Y., 2015, Revision of the pulchella - group of Alona s. lato leads to its translocation to Ovalona Van Damme et Dumont, 2008 (Branchiopoda: Anomopoda: Chydoridae), Zootaxa 4044 (4), pp. 451-492 : 455-456

Key for world fauna of Ovalona

1 Basal spine of postabdominal claw very small............................................................... 2

- Basal spine of postabdominal claw normally developed...................................................... 3

2 Postabdomen straight, with parallel margins............... XVI. O. karelica ( Stenroos, 1897) . Central and North Europe.

- Postabdomen curved, with convex ventral and concave dorsal margin..... XIII. O. bromelicola (Smirnov, 1998) . Nicaragua.

3 Middle abdominal segment is covered by dense setulation....... II. O. nigra ( Smirnov, 1996) . Chilean and Bolivian Andes.

- Middle abdominal segment is not covered by dense setulation.................................................. 4

4 Lateral head pores with rounded cavities.......................I. O. nuragica ( Margaritora, 1971) . West Mediterranean.

- Lateral head pores minute, without cavities................................................................. 5

5 Rostrum with characteristic posterior bulge.................XII. O. capensis ( Rühe. 1914) . Cape Peninsula, South Africa.

- Rostrum of normal morphology..........................................................................6

6 Postabdomen elongated, narrow, with parallel margins (height-length ratio over 2.5)................................ 7

- Postabdomen shorter and wide, of different shape (height-length ratio 2.4 or less).................................. 11

7 Two-three distalmost denticles of postabdomen much longer and thicker than following denticles. Lateral fascicles of setulae narrow, widely spaced............................................. X. O. archeri ( Sars, 1888) . Australia, Thailand.

- All denticles of postabdomen are of same size or size of denticles evenly decreasing distally. Lateral fascicles of setulae wide, spaced close to each other............................................................................... 8

8 All postanal marginal denticles of similar size. Postero-ventral angle of valves usually with 1–2 denticles................................................... XI. O. aguascalientensis ( Sinev & Silva-Briano, 2012) . Central Plateau of Mexico.

- Size of postanal marginal denticles of postabdomen evenly decreases basally. Postero-ventral angle of valves without denticles....................................................................................................9

9 Main head pores without connection between them.................................................................................. XV. O. cambouei ( Guerne & Richard, 1893) . Africa, Mediterranean, subtropical and tropical Asia.

- Main head pores fully connected........................................................................ 10

10 Posterior margin of head shield without notches or with single notch in the middle..........................................................................................XIV. O. glabra ( Sars, 1901) . Neotropics, including Andes.

- Posterior margin of head shield with symmetrical 6–8 notches.....XVII. O. pulchella ( King, 1853) . Australia and Tasmania.

11 Distalmost seta in anterior group of setae on valves much longer than previous setae. Postabdomen evenly narrowing distally, with obtuse distal angle.......................IV. O. anamariae ( Sinev & Silva-Briano, 2012) . Central Mexican Plateau.

- Distalmost seta in anterior group of setae on valves of same length as previous setae. Postabdomen with maximum width at the middle of postanal margin.............................................................................. 12

12 All main head pores fully connected...................................................................... 13

- Connection between some pores interrupted or absent........................................................ 14

13 All postanal marginal denticles long, of similar length, their length exceed width of postabdominal claw base.............................................................. III. O. altiplana ( Kotov, Sinev & Berrios, 2010) . Chilean Andes.

- Size of postanal marginal denticles decreases basally, length of most denticles less than width of postabdominal claw base (length of longest, distal denticles can be equal to the width of postabdominal claw base)............................ 15

14 Postanal margin of postabdomen with clusters of 3–5 short elementary denticles. Length of adult female 0.5–0.65 mm. Major head pores located far from posterior margin of head shield, PP about 0.6–0.7 IP................................................................................................IX. O. weinecki ( Studer, 1878) . Subantarctic islands.

- Postanal margin of postabdomen with well-developed composite denticles. Length of adult female 0.33–0.4 mm. Major head pores located close to posterior margin of head shield, PP less than 0.2 IP.................................................................................... VII. O. kaingang (Sousa, Elmoor-Loureiro & Santos, 2015). South Brazil.

15 Connections between all main head pores interrupted. Distal part of head shield broadly rounded....................................................................................VIII. O. setulosa ( Megard, 1967) . North America.

- Connection between anterior and middle pores uninterrupted, between central and posterior pore absent. Distal part of head shield forms angle................................................................................... 16.

16 Distal part of head shield forms acute angle. Distance between medium and posterior major head pore increases with the size of specimen, varying from 1.5 to 2.5 distances between anterior and middle pore. Length up to 0.48 mm ...................................................... VI. O. azorica ( Frenzel & Alonso, 1988) Azores Islands , West Iberian peninsula.

- Distal part of head shield forms angle with rounded tip. Distance between medium and posterior major head pore equal to about 1.0–1.5 distance between anterior and middle pore. Length up to 0.6 mm .............................................. V. O. anastasia ( Sinev, Alonso, Miracle & Sahuquillo, 2012) . South-East of Iberian Peninsula, West Mediterranean.