Stygnopsidae Sørensen, 1932

Cruz-López, Jesús A. & Francke, Oscar F., 2020, Two new genera of epigean harvestmen (Opiliones, Stygnopsidae) from Oaxaca, Mexico, with an identification key for the stygnopsine genera, Zootaxa 4748 (3), pp. 431-454 : 432-433

Stygnopsidae Sørensen, 1932

Stygnopsinae Sørensen, 1932

Diagnosis. Modified from Cruz-López & Francke (2017): Ocularium on frontal margin of prosoma varying in size from slightly elevated to very large; mesotergal sulci straight and smooth; chelicera usually large, with heterogeneous dentition; pedipalpal femur and patella without mesal setiferous tubercles; penis with the base of pars distalis forming an angle of 40º or more with respect to the flimsy lamina; macrosetae in five groups (A–E), in different arrangements as the patterns Stygnopsis (five groups recognizable, with two or three macrosetae each one) and Paramitraceras (numerous macrosetae on groups C and A+B); other unrecognizable patterns are also exhibited. Mexotroglinus is an aberrant genus that has a combination of features of both subfamilies, but is allocated into Stygnopsinae based upon molecular data; it exhibits mesotergal sulci straight as the only character of Stygnopsinae ( Cruz-López & Francke, 2017).

Identification key of the Stygnopsinae genera. On the basis of a total evidence phylogeny of the Stygnopsidae, Cruz-López & Francke (2017) proposed a subfamilial arrangement of the family, recognizing Karosinae and Stygnopsinae. Regarding the Stygnopsinae, Cruz-López & Francke (2017) also clarified the taxonomic status of the conflictive Hoplobunus and Stygnopsis Sørensen, 1902 , two of the more neglected genera of the family. Despite this effort, these authors did not provide an identification key for the genera of this subfamily. Thus, in this work we provide the first identification key for all stygnopsine genera, including taxa recently described. For further details regarding morphological nomenclature and taxonomic determination for species level, see: Aguiñaga & Cruz-López (2019), Cruz-López & Francke (2017, 2018, 2019 a, 2019b) and Cruz-López et al. (2019).

1. Mid-bulge of scutum with clear lateral projections........................................................... 2

- Mid-bulge of scutum without clear lateral projections......................................................... 6

2. Dorsal and free tergites fused in a scutum completum.................................................... Philora

- Dorsal and free tergites fused in a scutum magnum........................................................... 3

3. Troglomorphic, eyes absent, femur IV longer than scutum length, males without ventral glandular tubercles.................................................................................................... Troglostygnopsis

- Non-troglomorphic, eyes present, femur IV shorter than scutum length, males with or without ventral glandular tubercles.. 4

4. Ocularium with a sharp tip, pointing forward; pedipalpal tibia and tarsus without spiniform setiferous tubercles, males with ventral glandular tubercles.............................................................................. 5

- Ocularium rounded apically, pedipalpal tibia and tarsus with spiniform setiferous tubercles, males with ( S. parvula ) or without ( S. armigera ) ventral glandular tubercles............................................................ Sbordonia

5. Stigmatic area inverse T-shaped, pedipalpal tibia with two apical apophyses........................... Paramitraceras

- Stigmatic area triangular, pedipalpal tibia without two apical apophyses................................... Panzosus

6. Mesotergal area V with a large central spine.......................................................... Minisge

- Mesotergal area V without a large central spine.............................................................. 7

7. Mesotergal area IV with a pair of large paramedian large spines............................................ Iztlina

- Mesotergal area IV without armature...................................................................... 8

8. Mesotergal area III with a pair of paramedian spines......................................................... 9

- Mesotergal area III without a pair of paramedian spines...................................................... 10

9. Cheliceral movable finger with a prominent basal tooth, pedipalpal patella without a ventral apophysis..................................................................... Stygnopsis , in part [for S. valida , S. mexicana and S. robusta ]

- Cheliceral movable finger without a prominent basal tooth, pedipalpal patella with a ventral apophysis............. Isaeus

10. Ocularium in the middle of prosoma........................................................... Mexotroglinus

- Ocularium at the frontal margin of prosoma............................................................... 11

11. Pedipalpal patella with dorso-apical apophysis..................................................... Hoplobunus

- Pedipalpal patella unarmed and without dorso-apical apophysis................................................ 12

12. Femur IV without two remarkable ventral rows of spiniform tubercles.......................................... 13

- Femur IV with two remarkable ventral rows of spiniform tubercles............................................. 14

13. Ocularium with apical spine...................................................................... Tonalteca

- Ocularium rounded apically.............. Chinquipellobunus , in part [for Ch. madlae , Ch. russelli and Ch. coahuilaensis ]

14. One ventral row of tubercles of femur IV decreasing in size distally.................................... Serrobunus

- Two ventral rows of tubercles of femur IV increasing in size distally............................................ 15

15. Tubercles of both ventral rows on femur IV with similar size.................................................. 16

- Tubercles of the retrolateral row on femur IV much larger than those on the prolateral row......... Guelaguetzia gen. nov.

16. Pedipalpal patella with dorso-apical rounded apophysis............ Stygnopsis in part [for S. apoalensis and S. oaxacensis ]

- Pedipalpal patella without dorso-apical rounded apophysis................................................... 17

17. Anal plate with long cylindrical setiferous tubercles, tubercles of femur IV tooth-shaped and short... Ampliphallus gen. nov.

- Anal plate without cylindrical setiferous tubercles, tubercles of femur IV spiniform and long........................ 18

18. Pars distalis of penis covered by more than 30 macrosetae..................................... ‘Hoplobunus’ zullinii

Pars distalis of penis covered by at most five lateral macrosetae in groups C, A and B................................................................................. Chinquipellobunus , in part [for Ch. osorioi and Ch. mexicanus ]