Hylomyrma praepotens Kempf, 1973

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 : 90-94

Hylomyrma praepotens Kempf, 1973

Figures 59 , 60 , 61 , 90 (map)

Hylomyrma praepotens Kempf, 1973: 245 (W). Holotype: COLOMBIA: Amaz.[ Amazonas ]: 7km NW Letícia , 20-25 Feb 1972, #230, forest litter, berlesate, S. & J. Peck [leg.] (1W) (MCZ35421) [ MCZC] [examined]. Paratypes: same data as holotype (5W) (MCZ35421) [ MCZC] [examined] ; (2W 1I) ( MZSP67410 ) [ MZSP] [examined] ; Meta: Villavicencio , 1-4 Mar 1972, S. & J. Peck, 233, forest litter, berlesate (2I, one covered with gold) ( MZSP67411 ) [ MZSP] [examined] ; same data (1I) (ANTWEB-1008992 MZSP67409 ) [ MZSP] [examined].

Diagnosis. Large-sized; regular to irregular, longitudinal and thick striae on head dorsum diverge towards posterior margin, interspaces between striae smooth; propodeal spine long; a pair of large and blunt teeth laterally on anterior margin of clypeus; dorsal margin of petiole continuous, convex; subpostpetiolar process weak, convex; profemur mostly covered with irregular to regular transverse striae; protibia entirely covered with regular striae; very long striae on tergum of first gastral segment; semicircular striae on sternite of first gastral segment covering the midbasal and lateral regions.

Redescription. WORKER (n=4) ( Fig. 59A–C ): HL 1.22 (1.20–1.24); HW 1.20 (1.18–1.22); ML 0.82 (0.82); SL 0.90 (0.90–0.94); MOD 0.32 (0.30–0.34); PNW 0.82 (0.82–0.84); WL 1.54 (1.54–1.58); PSL 0.42 (0.36–0.43); PL 0.75 (0.75–0.77); PW 0.28 (0.26–0.28); PPL 0.42 (0.40–0.42); PPW 0.42 (0.40–0.42); GL 1.58 (1.36–1.59); TL 6.33 (6.10–6.40); CI 98.36 (96.72–100); SI 75 (75–78.81); OI 26.66 (25.42–27.87). Large-sized. Shiny integument. Brownish body, lighter petiole, postpetiole and leg. Thin and unbranched setae, long to midsized, erect to subdecumbent.

Head subquadrate; posterior margin slightly concave at middle. Mandible masticatory margin with 6 teeth. Anterior margin of clypeus slightly concave medially, with a pair of large and blunt teeth laterally; median area of clypeus centrally striate, with 10 regular and longitudinal striae converging to a point on the anterior margin, interspaces distinguishable. Frontal triangle with 1 sagittal stria. Short scape, not reaching head posterior margin; apical antennomere slightly shorter than previous 3 antennomeres together. Frontal carina slightly concave posterior to antennal socket. Eye drop-shaped, large-sized, larger diameter with 16 ommatidia. Head dorsum with regular to irregular, longitudinal and thick striae, divergent towards posterior margin, interspaces smooth. Longitudinal striae on head lateral and laterodorsal regions converge to mandible insertion; gena striate, around 5–7 regular and semicircular striae circumscribe the torulus, not reaching eye margin. Interspaces between striae on head ventral surface distinguishable.

Mesosoma sculpture similar to head dorsum, striae of uniform thickness assuming multiple directions; transverse striae on pronotum anterior region (DV) continuing on lateral surface, longitudinal striae on other regions of pronotum and metanotal groove region (anteriorly to transverse carina); irregular striae on mesonotum assuming more than one direction. Promesonotal junction and metanotal groove indistinct. Transverse carina inconspicuous. Dorsal margin of mesosoma continuous, convex. Propodeal lobe bidentate, dorsal tooth slightly longer and acute than the shorter and blunt ventral tooth; dorsal tooth length 1 / 2 of propodeal spine length. Propodeal spine long, straight (LV), divergent (DV), sculptured. Thin striae of uniform thickness on procoxa; irregular and transverse striae on C2 and C3. Profemur mostly covered with irregular to regular transverse striae. Protibia entirely covered with regular striae.

Dorsal margin of petiole continuous, convex; sculpture similar to mesosoma; mostly covered with transverse striae; ventral surface smooth. Regular and longitudinal striae on postpetiole; subpostpetiolar process striae restricted to lateral region, midbasal region smooth; subpostpetiolar process weak, convex.

First gastral segment striation similar to postpetiole striae; length of long striae on tergum similar to postpetiole length; semicircular striae on sternite covering the midbasal and lateral regions.

QUEEN (first description) (n=1) ( Fig. 60A–C ): HL 1.20; HW 1.24; ML 0.84; SL 0.90; MOD 0.34; PNW 1; WL 1.78; PSL 0.38; PL 0.83; PW 0.32; PPL 0.44; PPW 0.47; GL 1.66; TL 6.75; CI 103.33; SI 72.58; OI 27.41. Largesized. Color, pilosity, and some sculpture characters shared with conspecific workers, only slightly larger. Larger diameter of eye with 18 ommatidia. Longitudinal, regular to irregular striae on scutum going from an anterior central point towards transcutal suture, interspaces distinguishable. Longitudinal and mostly regular striae on anepisternum and katepisternum, interspaces distinguishable. Axilla and scutellum with same sculpture of scutum. Scutoscutellar sulcus inconspicuous. Transverse striae on propodeum (DV). Lateral of mesosoma with mostly irregular striae directed to propodeal spine, interspaces distinguishable. Wings unknown.

MALE Unknown.

Etymology. The specific epithet praepotens (Latin, prae = pre-, before, very and potens = powerful) is possibly a reference to the head sculpture or to the long clipeal teeth of this species.

Comments. Hylomyrma praepotens , the largest species of the genus, is similar to H. immanis , both have a long propodeal spine, and an elongated and continuous dorsal margin of petiole, but H. praepotens is easily distinguished by the shiny integument (subopaque in H. immanis ), and the body covered by thick striae with distinguishable interspaces (thin striae with indistinguishable interspaces in H. immanis ). Hylomyrma immanis is more easily sampled than H. praepotens , the former has a broad distribution in the center-north of South America ( Fig. 88 ), whereas the latter is only known from two localities in Colombia, two in Ecuador, and one in Brazil ( Fig. 90 ). Both species cooccur in a locality 7 km NW of Letícia, Amazonas, Colombia.

Four type specimens, identified as workers by Kempf (1973), have an inconspicuous central ocellus, and a darker area on the head dorsum coincident with the ocelli location in winged queens ( Fig. 61 ). They also have the mesosoma larger and more convex than in workers. Due to these characters, we rcognized these specimens as intercastes.

Distribution. The few known specimens were collected in Brazil, Colombia, and Ecuador ( Fig. 90 ).

Natural history. The type specimens were collected with Berlese-Tüllgren funnels in Colombia, and the unique specimen from Brazil was collected with winkler extractors, suggesting that colonies are located in leaf-litter or in superficial soil layers. Except for the presence of intercastes (4 paratypes), there is no further information available regarding H. praepotens biology.

Additional material examined (12 workers, 1 queen): BRAZIL: MA[Maranhão]: São Francisco do Brejão , 05°17′19″S, 47°15′01.7″W, 01-09.vi.2005, Silva R.R. & Feitosa R.M. cols., Winkler 10 (1W) (MZHY202) [ MZSP] . ECUADOR: Napo: Limoncocha , 250m, 25.vi.1976, B-355, S. & J. Peck (11W) [ MCZC]; same except 18.vi.1976, B-348 (1Q) (MCZENT00524675) [ MCZC] .

Figures

FIGURE 59. Paratype worker of Hylomyrma praepotens (MZSP67409). A) frontal view; B) dorsal view; C) lateral view. Photos by Ricardo Kawada.

FIGURE 60. Queen of Hylomyrma praepotens (MCZENT00524675). A) frontal view; B) dorsal view; C) lateral view. Photos by M.A. Ulysséa.

FIGURE 61. Paratype intercaste of Hylomyrma praepotens (MZSP67410) in frontal view. Photo by Guilherme Ide.

FIGURE 88. Distribution records of Hylomyrma immanis, H. mariae, H. primavesi, and H. versuta.

FIGURE 90. Distribution records of Hylomyrma praepotens.