Key to species of the T. opinatus subgroup

1 Spatulate lobe (sl) distally drawn out into one (rarely two) sharp dark brown spine(s).............................................. 2

1* Spatulate lobe (sl) distally expanded and/or rounded, spoonlike, without a spine ...................................................... 6

2 Spatulate lobe (sl) terminating in two sharp brown spines, the outer spine slightly smaller and shorter than the inner one; lateral process of anterior coxal fold (alp) slender, slightly curving mesad; mesal process of anterior coxal fold (amp) almost as long as alp, flattened ........................................................................ Thyropygus bispinispatula n. sp.

2* Spatulate lobe (sl) terminating in a single sharp dark brown spine .............................................................................. 3

3 Telopodite distally to fe with a large, round lobe (lo) projecting distolaterally............................................................ 4

3* Telopodite without a lobe distal to fe; lateral process of anterior coxal fold (alp) long, slender, regularly curved, tip

close to tip of opposite alp, the two together forming a circle; mesal process of anterior coxal fold (amp) straight, shorter than alp; femoral spine (fe) directed distad, pointed .................................................. Thyropygus erectus n. sp. 4 Lateral process of anterior coxal fold (alp) very slender, regularly curved, simple, tip close to tip of the opposite side, the two together forming a circle; mesal process of posterior coxal fold (pmp): strongly developed along anterior-posterior axis ................................................................................ Thyropygus floweri (Demange, 1961) n. comb.

4* Lateral process of anterior coxal fold (alp) different, broader and/or with several apical denticles ........................... 5

5 Lateral process of anterior coxal fold (alp) broad, apically gradually narrowed; mesal process of anterior coxal fold (amp) almost as long as lateral process (alp), slender, straight, terminally slightly curved, pointed ............................. .............................................................................................................. Thyropygus opinatus (Karsch, 1881) n. comb.

5* Lateral process of anterior coxal fold (alp) apically bent abruptly mesad, tip with serrate margins; mesal process of anterior coxal fold (amp) much shorter than lateral process (alp), directed meso-distad, simple, pointed; mesal process of posterior coxal fold (pmp): strongly developed along anterior-posterior axis.................................................... ....................................................................................................... Thyropygus implicatus (Demange, 1961) n. comb.

6 Lateral process of anterior coxal fold (alp) broad, mesal margin concave, tip with serrate margins, cockscomb-like; mesal process of anterior coxal fold (amp) much shorter than lateral process (alp), directed meso-distad, simple, pointed; an additional spine-like process (aip) between alp and amp ............................. Thyropygus cristagalli n. sp.

6* Lateral process of anterior coxal fold (alp) slender, regularly curved, no additional process between lateral (alp) and mesal (amp) ones ......................................................................................................................................................... 7

7 Lateral process of anterior coxal fold (alp) apically abruptly truncate .................................... Thyropygus bearti n. sp.

7* Lateral process of anterior coxal fold (alp) apically pointed........................................................................................ 8

8 Mesal process of anterior coxal fold (amp) very small, telopodite distally to fe with a small round lobe (lo) projecting distolaterally ........................................................................................................................ Thyropygus loxia n. sp.

8* Mesal process of anterior coxal fold (amp) relatively long.......................................................................................... 9

9 Mesal process of anterior coxal fold (amp) much shorter than lateral process (alp), directed obliquely disto-mesad, slender, straight. ................................................................................................................... Thyropygus chelatus n. sp.

9* Mesal process of anterior coxal fold (amp) directed distad, thicker, straight or slightly sigmoid ............................. 10

10 Mesal process of anterior coxal fold (amp) almost as long as lateral process (alp), slightly sigmoid, pointed; mesal process of posterior coxal fold (pmp) directed distolaterad ..................................... Thyropygus brachyacanthus n. sp.

10* Mesal process of anterior coxal fold (amp) longer than lateral process (alp), directed distad, parallel with opposite process......................................................................................................................................................................... 11

11 Lateral process of anterior coxal fold (alp) apically with a crest extending caudad and ending in a small spine; mesal process of anterior coxal fold (amp) apically irregularly tuberculate; telopodite distally without a rounded lobe (lo); femoral spine (fe) short; spatulate lobe (sl) distally rounded, with smooth edges.......................................................... ........................................................................................................... Thyropygus inflexus (Demange, 1989) n. comb.

11* Lateral process of anterior coxal fold (alp) apically without a crest; mesal process of anterior coxal fold (amp) apically sharp; telopodite distally with a rounded lobe (lo); femoral spine (fe) long; margins of spatulate lobe (sl) terminally meeting in a distinct angle .......................................................................................... Thyropygus bispinus n. sp.