Hylomyrma, : Brown, 1953

Ulysséa, Mônica Antunes, 2021, Taxonomic revision of the Neotropical ant genus Hylomyrma Forel, 1912 (Hymenoptera: Formicidae: Myrmicinae), with the description of fourteen new species, Zootaxa 5055 (1), pp. 1-137 : 12-18

Key to species of Hylomyrma based on workers

1. Propodeal lobe bidentate ( Fig. 3B )........................................................................ 2

- Propodeal lobe unidentate, dorsal region rounded ( Fig. 3A ) ( Peru)................................ H. wachiperi n. sp.

2(1). Dorsal margin of petiole continuous, anterior surface of node not differentiated from anterior peduncle ( Fig. 4A–B )....... 3

- Dorsal margin of petiole discontinuous, anterior surface of node differentiated from anterior peduncle ( Fig. 4C )......... 12

3(2). Dorsal margin of petiole strongly convex ( Fig. 4A ).......................................................... 4

- Dorsal margin of petiole slightly convex ( Fig. 4B )........................................................... 6

4(3). Striae on dorsal surface of head with smooth crests ( Fig. 5A ); mesosoma with a few elliptic and concentric striae; postetiolar dorsum and gaster smooth ( Brazil)............................................................. H. villemantae

- Striae on dorsal surface of head with punctuated appearance ( Fig. 5B–C ); mesosoma longitudinally striate; postpetiolar dorsum and base of first gastral segment with longitudinal striae...................................................... 5

5(4). In lateral view, striae of mesosoma directed to propodeal spine ( Fig. 6A ); petiole mesoventral surface armed with conspicuous spine; petiolar dorsum with transverse and longitudinal striae; subpostpetiolar process more prominent (SPP 0.13–0.14 mm) ( Guyana, French Guiana)............................................................... H. margaridae n. sp.

- In lateral view, striae of mesosoma directed to propodeal dorsum ( Fig. 6B ); petiole mesoventral surface armed with inconspicuous subtriangular projection; petiolar dorsum entirely covered with transverse striae; subpostpetiolar process less prominent (SPP 0.11–0.12 mm) ( Guyana, Venezuela).................................................... H. peetersi n. sp.

6(3). Procoxa striae with variable thickness ( Fig. 7A ); postpetiolar dorsum predominantly smooth......................... 7

- Procoxa striae with uniform thickness ( Fig. 7B ); postpetiolar dorsum striate....................................... 8

7(6). Regular and irregular striae on mesosoma, interspaces between striae smooth; dorsal margin of mesosoma somewhat straight (mesosoma slightly flattened dorsally) ( Fig. 8A ) ( Costa Rica, Ecuador, Panama)........................... H. montana

- Mesosoma covered with irregular to vermicular striae of variable thickness, interspaces indistinguishable; dorsal margin of mesosoma notably convex ( Fig. 8B ) ( Colombia, Ecuador)...................................... H. lispectorae n. sp.

8(6). Eye reniform ( Fig. 9A ); propodeal spine relatively short (PSL 0.21–0.24 mm) ( Costa Rica, Panama)..... H. jeronimae n. sp.

- Eye drop-shaped (anterior region narrower than posterior region) ( Fig. 9B ); propodeal spine relatively long (PSL 0.25–0.58 mm)................................................................................................ 9

9(8). Subtriangular projection on mesoventral surface of petiole present (anterior to petiolar spiracle) ( Fig. 10A–B ); subpostpetiolar process very prominent ( Fig. 10A ) ( Brazil, Guyana, French Guiana, Suriname)............................. H. reginae

- Subtriangular projection on ventral surface of petiole absent; subpostpetiolar process less prominent ( Fig. 10C–D )....... 10

10(9). Integument predominantly subopaque, covered with very thin striae (microsculpture) superimposed on vermicular striae (macrosculpture), interspaces between striae indistinguishable ( Bolivia, Brazil, Colombia, Ecuador, Guyana, French Guiana, Peru, Trinidad and Tobago, Venezuela)................................................................. H. immanis

- Integument shinier, covered with thick striae, interspaces distinguishable........................................ 11

11(9). Regular to irregular striae on mesosoma; transverse striae on petiolar dorsum; sternite of the first gastral segment with semicircular striae covering the midbasal and lateral regions ( Brazil, Colombia, Ecuador)........................ H. praepotens

- Vermicular striae on mesosoma; petiolar dorsum mostly covered with irregular to vermicular striae; sternite of the first gastral segment with striation restricted to laterobasal region ( Colombia)......................................... H. sagax

12(2). Antennal scape relatively long, surpassing the posterior margin of head in full-face view (SI 88.37–100 mm); vermicular striae on mesonotum ( Fig. 11A ).............................................................................. 13

- Antennal scape relatively short, never surpassing the posterior margin of head in full-face view (SI 65.16–81.81 mm); mesonotum striae variously shaped, but never vermicular........................................................... 14

13(12). Thick, dark and unbranched setae ( Fig. 11B ) ( Bolivia, Brazil, Ecuador, French Guiana, Peru).......... H. marielleae n. sp.

- Thin, light and branched setae ( Fig. 11C ) ( Brazil, Ecuador, Peru, Suriname, Venezuela).................... H. longiscapa

14(12). Interspaces between striae on mesosomal dorsum indistinguishable ( Fig. 12A ).................................... 15

- Interspaces between striae on mesosomal dorsum smooth ( Fig. 12B )............................................ 21

15(14). Mesonotal striae predominantly longitudinal ( Fig. 12A–B )................................................... 16

- Mesonotal striae predominantly transverse ( Fig. 13A–C )..................................................... 19

16(15). Body covered with conspicuous and branched setae, trifid ( Costa Rica).................................. H. plumosa

- Body mostly covered with thin and unbranched setae; if branched setae present, they are inconspicuous................ 17

17(16). Eye oval; metanotal groove distinguished by a slight depression; propodeal spine long (PSL 0.28–0.34 mm); postpetiolar dorsum with longitudinal, discontinuous and slightly curved striae ( Fig. 14A ) ( Colombia, Ecuador).......................................................................... H. macielae n. sp. (in part; specimens from Leticia, Colombia)

- Eye reniform or drop-shaped; metanotal groove indistinct; propodeal spine short (PSL shorter than 0.27 mm); postpetiolar dorsum with longitudinal, continuous and regular striae ( Fig. 14B–C )........................................... 18

18(17). Dorsal margin of mesonotum convex dorsally; propodeal spine slightly longer than the dorsal tooth of propodeal lobe (PSL 0.20–0.27 mm); striae length on first gastral segment similar to postpetiolar length ( Fig. 14B ) ( Bolivia, Brazil, Colombia, Ecuador, Guyana, French Guiana, Peru, Suriname, Trinidad and Tobago, Venezuela)......................... H. blandiens

- Dorsal margin of mesonotum straight (mesonotum flattened dorsally); propodeal spine very short (PSL 0.15–0.16 mm), shorter than the dorsal tooth of propodeal lobe; striae length on first gastral segment shorter than postpetiolar length, restricted to basal region ( Fig. 14C ) ( Panama).................................................................... H. dentiloba

19(15). Striae on mesonotum predominantly straigh ( Fig. 13A ) ( Bolivia, Brazil, Colombia, Peru).................. H. transversa

- Striae on mesonotum semicircular ( Fig. 13B–C )............................................................ 20

20(19). Eye midsize (MOD 0.21–0.24 mm), 13 facets at maximum diameter, drop-shaped; propodeal spine short (shorter than 2× the dorsal tooth of propodeal lobe); first half of petiolar node dorsum with semicircular striae, and second half with longitudinal striae; unbranched setae with sharp tip ( Colombia, Venezuela)........................................ H. columbica

- Eye large (MOD 0.26–0.30 mm), 16–18 facets at maximum diameter, reniform; propodeal spine long (2× or longer than the dorsal tooth of propodeal lobe); dorsum of petiolar node with longitudinal striae; branched setae with lobed ends ( Colombia, Ecuador, Venezuela).......................................................................... H. dolichops

21(14). Head dorsum with vermicular to vermiculated-areolated striae ( Fig. 15A–B ); postpetiolar dorsum and base of first gastral segment with anastomosed longitudinal striae................................................................ 22

- Head dorsum with longitudinal striae that are regular ( Fig. 15C ), irregular ( Fig. 15D ), or rugose ( Fig. 15E ); postpetiolar dorsum and base of first gastral segment with longitudinal striae not anastomosed........................................ 23

22(21). Gena and laterodorsal region of head covered with very thin striae (microsculpture) superimposed on vermicular to vermiculated-areolated striae (macrosculpture); dorsal margin of mesosoma continuous (LV), metanotal groove indistinct; subpostpetiolar process weak and slightly convex ( Colombia, Ecuador)...................................... H. virginiae n. sp.

- Gena and laterodorsal region of head covered with very thin striae (microsculpture) between the vermicular to vermiculatedareolated striae; dorsal margin of mesosoma discontinuous (LV), metanotal groove distinguished by a slight depression (LV) and altered sculpture (DV); subpostpetiolar process prominent and subtriangular ( French Guiana).......... H. mitiae n. sp.

23(21). Striae on mesosoma rugose ( Fig. 16A )................................................................... 24

- Striae on mesosoma regular ( Fig. 12B ) or irregular ( Fig. 16B )................................................. 29

24(23). Small to midsized ant (TL 4.28–5.23 mm, WL 1.08–1.40 mm); brownish body; propodeal spine longer than the dorsal tooth of propodeal lobe...................................................................................... 25

- Large-sized ant (TL 5.32–5.78 mm, WL 1.34–1.48 mm); black body; propodeal spine with length similar to the dorsal tooth of propodeal lobe ( Brazil)................................................................... H. primavesi n. sp.

25(24). Posterior surface of profemur mostly smooth; base of first gastral segment with short striae, shorter than postpetiole length 26

- Posterior surface of profemur with transverse striae; first gastral segment with long striae, similar to or longer than postpetiole length............................................................................................. 28

26(25). Dorsal margin of mesosoma continuous, without differentiated metanotal groove ( Fig. 16A ) ( Argentina, Brazil, Paraguay).............................................................................................. H. balzani

- Dorsal margin of mesosoma discontinuous, metanotal groove distinguishable by altered sculpture ( Fig. 17A–B ) or a slight depression ( Fig. 17C )................................................................................. 27

27(26). On side of head, thinner striae (microsculpture) occur between the thicker striae (macrosculpture); striae on petiolar node mostly transverse; striae on postpetiolar tergite regular and longitudinal, striae weakly marked on lateral and posterior regions ( Colombia)............................................................................ H. dandarae n. sp.

- On side of head, thinner striae are superimposed on thicker striae; striae on petiolar node mostly longitudinal; striae on postpetiolar tergite regular and longitudinal, striae well-marked ( Colombia, Ecuador)........................ H. macielae n. sp.

28(25). Metanotal groove distinguished by a depression; propodeal spine very long (PSL 0.32–0.37 mm), longer than 2× the dorsal tooth of propodeal lobe; dorsum of petiolar node with rugose striae ( Colombia)........................ H. mariae n. sp.

- Metanotal groove indistinct; propodeal spine short (PSL 0.22–0.26 mm), shorter than 2× the dorsal tooth of propodeal lobe; dorsum of petiolar node with irregular and transverse striae ( Bolivia)................................ H. adelae n. sp.

29(23) Longitudinal striae on head dorsum irregular and with variable thickness; striae on mesosomal dorsum irregular, interspaces in part smooth and in part with thin striation; longitudinal striae on first gastral tergite slightly shorter than postpetiolar length ( Fig. 18A ) ( Belize, Colombia, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, Panama)..................... H. versuta

- Longitudinal striae on head dorsum regular ( Fig. 15C ); striae on mesosomal dorsum regular to irregular, interspaces smooth ( Fig. 12B ); longitudinal striae on first gastral tergite slightly shorter than 1 / 3 of postpetiolar length ( Fig. 18B )............ 30

30(29). Striae between frontal carina (posterior to torulus) and eye margin irregular; in lateral view, mesosomal striae directed to propodeal dorsum; ventral surface of petiole smooth ( Brazil, Paraguay)...................................... H. reitteri

- Striae between frontal carina and eye margin rugose; in lateral view, mesosomal striae directed to propodeal spine; ventral surface of petiole striate ( Brazil).............................................................. H. lopesi n. sp.

Figures

FIGURE 3. Lateral view of propodeum; propodeal lobe outlined. A) H. wachiperi (MZSP67468); B) H. mariae paratype (MZSP67393).

FIGURE 4. Lateral view of petiole; dorsal margin of petiole outlined. A) H. margaridae paratype (USNMENT00688844); B) H. reginae (USNMENT00688778); C) H. columbica (COLOMBIA: on fiber plant from Colombia at Quarantine [USNM]).

FIGURE 5. Frontal view. A) H. villemantae (MZHY199 [MZSP]), photo by M.A. Ulysséa; B) H. peetersi paratype (USN- MENT00413896); C) H. margaridae paratype (USNMENT00688844), photos by Ricardo Kawada.

FIGURE 6. Lateral view of mesosoma. A) H. margaridae paratype (USNMENT00688844); B) H. peetersi paratype (USN- MENT00413896).

FIGURE 7. Lateral view of procoxa. A) H. lispectorae paratype (MZSP67347); B) H. columbica (COLOMBIA: on fiber plant from Colombia at Quarantine [USNM]).

FIGURE 8. Lateral view of mesosoma. A) H. montana (MZSP67433); B) H. lispectorae paratype (MZSP67347).

FIGURE 9. Lateral view of head; eye format outlined. A) H. jeronimae paratype (MZSP67341); B) H. blandiens (MZSP67435).

FIGURE 10. Lateral view of petiole and postpetiole; projection on mesoventral surface of petiole (black) and subpostpetiolar process (white) pointed. A) H. reginae (USNMENT00688778); B) drawing of H. reginae holotype from Kutter, 1977; C) H. immanis (MZSP67335); D) H. praepotens (MZSP67411).

FIGURE 11. Dorsal view of mesosoma. A-B) H. marielleae paratype (MZSP67399); C) H. longiscapa (MZSP67436).

FIGURE 12. Dorsal view of mesosoma; striae type (regular) outlined. A) H. blandiens (MZSP67435); B) H. reitteri (MZSP67443).

FIGURE 13. Dorsal view of pronotum and mesonotum; striae direction outlined. A) H. transversa (MZSP67452); B) H. columbica (COLOMBIA: on fiber plant from Colombia at Quarantine [USNM]); C) H. dolichops (COLOMBIA: Nariño: Orito, Territorio Kofan, 00°30’N, 77°13’W, 700m, Bosque caída, T2T6 [IHVL]).

FIGURE 14. Dorsal view of petiole and postpetiole. A) H. macielae paratype (MZSP67389); B) H. blandiens (MZSP67435); C) H. dentiloba (MZSP67320).

FIGURE 15. Frontal view.A) H. virginiae paratype (ECUADOR: Pichincha, 584 [IHVL]); B) H. mitiae holotype (MZSP67401), photo by Gabriel Biffi; C) H. reitteri (MZSP67443); D) H. dandarae paratype (COLOMBIA: Caquetá [IHVL]); E) H. adelae paratype (MZSP67312).

FIGURE 16. Dorsal view of mesosoma; striae type (A: rugose, B: irregular) outlined. A) H. balzani (MZSP67434); B) H. versuta (MZSP67461).

FIGURE 17. Dorsal (A-B) and lateral (C) view of mesosoma; promesonotal junction and metanotal groove outlined. A) H. dandarae paratype (COLOMBIA: Caquetá [IHVL]); B) H. primavesi paratype (MZSP67418); C) H. primavesi paratype (MZSP67418).

FIGURE 18. Dorsal view of postpetiole and gaster. A) H. versuta (MZSP67461); B) H. lopesi paratype (MZSP67385).