Key to the species of the genus Haasea

(based on the number of body segments and anterior gonopod structures)

1. Body with 28 body segments, including telson.............................................................. 2 - Body with 30 body segments, including telson............................................................. 11 2. Anterior lateral process (alp) present...................................................................... 3 - Anterior lateral process (alp) absent...................................................................... 8 3. Anterior lateral process (alp) poorly developed; mesal process (mp) knife-like, straight and pointing distad.... H. vidinensis

- Anterior lateral process (alp) strongly developed; mesal process (mp) slender and strongly curved porteriad............. 4

4. Anterior lateral process (alp) apically bifurcated..................................................... H. plasana

- Anterior lateral process (alp) simple...................................................................... 5

5. Mesal process (mp) with denticles........................................................ H. makarovi sp. nov.

- Mesal process (mp) without denticles..................................................................... 6

6. Posterior lamella (pl) vestigial; anterior lateral process (alp) laid, sabre-like, posterior half strongly bent distad..................................................................................................... H. lacusnigri

- Posterior lamella (pl) well-developed; anterior lateral process (alp) erect and straight............................... 7

7. Posterior lamella (pl) short, bent down into an extension........................................... H. microcorna

- Posterior lamella (pl) long, parallel with distal half of angiocoxite..................................... H. intermedia

8. Posterior lamella (pl) with distal notch.................................................................... 9

- Posterior lamella (pl) without distal notch................................................................. 10

9. Mesal process (mp) distal margin densely denticulated with an isolated posterior branch with or without small tooth............................................................................................... .. H. flavescens

- Mesal process (mp) distal margin with several teeth and with fork-like end.............................. H. hungarica

10. Posterior lamella (pl) ear-shaped, with distolateral thickening, bent down into an extension................. H. germanica

- Posterior lamella (pl) rounded, without distolateral thickening, not bent down into an extension............... H. pretneri

11. Mesal process (mp) denticulated........................................................................ 12

- Mesal process (mp) without denticles.................................................................... 17

12. Posterior lamella (pl) bilobed........................................................................... 13

- Posterior lamella (pl) simple........................................................................... 15

13. Mesal process (mp) hand-like, only with distal teeth.................................................. H. inflata

- Mesal process (mp) saw-like, strongly denticulated......................................................... 14

14. Posterior lamellae superposed, upper (pl1) one smaller, bent down into an extension........................ H. faucium

- Posterior lamellae (pl1, pl2) parallel to each other, almost of the same size and simply rounded................. H. filicis

15. Posterior lamella (pl) with distal notch.......................................................... H. flavescens

- Posterior lamella (pl) without distal notch................................................................. 16

16. Mesal process (mp) denticulated only at the anterodistal lobe...................................... H. fonticulorum

- Mesal process (mp) saw-like, strongly denticulated............................................. H. musimontium

17. Anterior lateral process (alp) present; mesal process (mp) elongated, sword-like; posterior lamella (pl) simple, robust and rounded................................................................................... H. cyanopida

- Anterior lateral process (alp) absent; mesal process (mp) short, columnar in shape; posterior lamella (pl) bilobed............................................................................................... H. gruberi sp. nov.