Hylomyrma dolichops 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 : 43-46

Hylomyrma dolichops Kempf, 1973

Figures 32 , 33 , 80G , 87 (map)

Hylomyrma dolichops Kempf, 1973: 239 (W, Q). Holotype: COLOMBIA: Amaz.[Amazonas]: 7km NW Letícia , 20–25 Feb 1972, #230, forest litter, berlesate, S. & J. Peck [leg.] (1W) (MCZ35419) [MCZC] [examined]. Paratypes: same data as holotype (2W 1Q) (MCZ35419) [MCZC] [examined]; (3W 1Q) ( MZSP67325 , MZSP67326 , MZSP67327 ) [MZSP] [examined].

Diagnosis. Anterior half of head dorsum with vermicular and divergent striae; posterior half with irregular and parallel striae; large and reniform eye; striae of variable thickness on mesosoma, interspaces indistinguishable; semicircular striae on mesonotum and metanotal groove region; dorsal margin of petiole discontinuous; profemur posterior surface mostly smooth; striae on protibia extensor surface weakly marked; long striae on tergum of first gastral segment; body with branched setae with multiple branches of equal size and lobed at tip.

Redescription. WORKER (n=4) ( Fig. 32A–C ): HL (0.92–1.04); HW 0.98 (0.94–1); ML 0.62 (0.62–0.68); SL 0.68 (0.62–0.72); MOD 0.32 (0.28–0.33); PNW 0.72 (0.70–0.78); WL 1.38 (1.30–1.44); PSL 0.42 (0.36–0.46); PL 0.69 (0.66–0.78); PW 0.31 (0.27–0.31); PPL 0.42 (0.40–0.46); PPW 0.40 (0.37–0.42); GL 1.32 (1–1.32); TL 5.43 (4.90–5.43); CI 98 (98–102.17); SI 69.38 (65.95–70); OI 32.65 (29.78–33). Medium to large-sized. Subopaque to shiny integument. Brownish to light brown body, darker head and gaster. Thin, unbranched and branched setae, long to short, suberect to subdecumbent; branched setae with multiple short branches of equal size and lobed at tip ( Fig. 80G ); unbranched setae mostly on head.

Head subquadrate; posterior margin straight. Mandible masticatory margin with 6 teeth. Anterior margin of clypeus straight medially, with a pair of small teeth laterally; median area of clypeus with 6–8 regular, longitudinal and thick striae, interval between thicker striae filled with thinner striae. Frontal triangle with 1 stria subdivided towards the posterior margin. Short scape, not reaching head posterior margin; apical antennomere with equal length to previous 3 antennomeres together, or slightly shorter. Frontal carina straight. Eye reniform, large-sized, larger diameter with 17 ommatidia. Longitudinal striae on head dorsum, vermicular and divergent striae on anterior half, irregular and parallel on posterior half; interspaces between thicker striae filled with thinner striae. Striation on lateral and laterodorsal regions of the head converging to eye margin; regular striae on head lateral and lateroventral regions, irregular to vermicular on laterodorsal region; gena striate, 6–9 regular and semicircular striae circumscribe the torulus, almost reaching eye margin. Interspaces between striae on head ventral surface striation indistinguishable.

Irregular to regular striae of variable thickness on mesosoma dorsum assuming multiple directions, striae forming swollen regions, interspaces indistinguishable; pronotum mostly covered with transverse striae continuing on lateral surface; semicircular striae on dorsum of mesonotum, metanotal groove region (immediate anterior to transverse carina) and propodeum. Irregular striae on lateral of pronotum and mesepisternum continuing on propodeum lateral and reaching the propodeal spine. Promesonotal junction and metanotal groove indistinct. Transverse carina inconspicuous. Dorsal margin of mesosoma continuous, convex. Propodeal lobe bidentate, acute dorsal tooth with similar length of blunt ventral tooth; dorsal tooth length shorter than 1 / 2 of propodeal spine length. Propodeal spine long, straight (LV), divergent (DV), sculptured on base. Thin striae of uniform thickness on procoxa; irregular and transverse striae on C2 and C3. Profemur covered with irregular to regular transverse striae weakly marked. Protibia extensor surface entirely covered with regular and longitudinal striae.

Dorsal margin of petiole discontinuous. Node elongated, convex; adjacent striae of variable thickness; regular and transverse striae on anterior surface continuing on lateral surface; irregular to vermicular longitudinal striae on lateral and dorsal surfaces; transverse striae on ventral surface weakly marked. Postpetiole and subpostpetiolar process with regular and longitudinal striae, interspaces indistinguishable; subpostpetiolar process prominent, convex.

First gastral segment striation similar to postpetiole striae; long striae on tergum, shorter than postpetiole length; sternite striation covering the laterobasal region.

QUEEN (n=2, paratypes) ( Fig. 33A–C ): HL 1.02–1.06; HW 1.02; ML 0.56–0.66; SL 0.72; MOD 0.34; PNW 0.86–0.88; WL 1.50–1.62; PSL 0.40; PL 0.72–0.74; PW 0.34; PPL 0.43–0.48; PPW 0.44–0.46; GL 1.36–1.42; TL 5.59–5.98; CI 96.22–100; SI 70.58; OI 33.33. Large-sized. Color, pilosity, and some sculpture characters shared with conspecific workers, only slightly larger. Larger diameter of eye with 18–20 ommatidia. Longitudinal, regular to irregular striae on scutum going from an anterior central point towards transcutal suture, interspaces indistinguishable. Longitudinal striae of uniform thickness on anepisternum and katepisternum, mostly regular on anepisternum and irregular on katepisternum, interspaces indistinguishable. Axilla and scutellum with same sculpture of scutum. Scutoscutellar sulcus inconspicuous. Transverse and regular striae on propodeum (DV), interspaces indistinguishable. Lateral surface of mesosoma with mostly irregular striae directed to propodeal spine, interspaces indistinguishable. Wings unknown.

MALE Unknown.

Etymology. Dolichops (Greek, dolichos = kidney-bean) is certainly a reference to the reniform eye of this species.

Comments. Hylomyrma dolichops is similar to H. columbica regarding the sculpture of the mesosomal dorsum, but the former is easily distinguished from the latter by the branched setae, whose branches are lobed at the tip ( Fig. 80G ). Hylomyrma columbica has unbranched setae. Also, Hylomyrma dolichops differs from H. columbica (characteristic in parentheses) in the presence of vermicular and divergent striae on anterior two-third of mesial area on head dorsum, irregular and parallel on the upper third (vs. regular striae on the mesial region in part directed towards posterior margin and in part anteriorly divergent and posteriorly convergent/parallel), and the reniform eye (vs. drop-shaped). The two species are allopatric; Hylomyrma dolichops shows a broader distribution ( Brazil, Colombia, Ecuador, and Venezuela) ( Fig. 87 ), whereas H. columbica occurs in Colombia and in western Venezuela ( Fig. 85 ).

Regarding morphological variation, three specimens from Orito , Colombia, are considerably larger than those described in the type series, although all other diagnostic characteristics are invariant .

Distribution. This species is known from Brazil, Colombia, Ecuador, and Venezuela ( Fig. 87 ).

Natural history. All specimens examined were collected in leaf-litter of tropical rainforest, at elevations ranging from 260 to 700 m, which suggests that nests are located between leaves, in fallen logs, rotten wood, or inside natural cavities of the superficial soil layers.

Additional material examined (7 workers): BR[ BRAZIL]: AC[Acre]: Mâncio Lima, P.N. da Serra do Divisor, 260m, 7°27′9.22″S, 73°39′58.24″W, 15–18.xi.2016, R.M. Feitosa, T.S. Silva & A.C. Ferreira cols. (2W) [ DZUP]. COLOMBIA: Nariño: Orito, Territorio Kofan, 700m, 00°30′N, 77°13′W, 28.ix.1998, E.L. González leg., Bosque, Winkler 7 (1W) [ IHVL] ; same data (1W) (MZHY197) [ MZSP] ; same except 29.ix.1998, caída, T2T6 (1W covered with gold) [ IHVL]. ECUADOR: Orellana: Tiputini Biodiversity Station , Jan2004 – Jan2006, A.L. Mertl col., dissertation 2009, litter nest, tropical rainforest, terra firme (1W) [ MCZC]. VEN[ VENEZUELA]: Amazonas: San Carlos de R. Negro, 11.oct.1981, L. Carling col., SCRN HR/JV (1W) [ MCZC] .

Figures

FIGURE 32. Worker of Hylomyrma dolichops (COLOMBIA: Nariño: Orito, Territorio Kofan, 00°30’N, 77°13’W, 700m, Bosque Winkler 7, 28.ix.1998 [IHVL]). A) frontal view; B) dorsal view; C) lateral view. Photos by Ricardo Kawada.

FIGURE 33. Paratype queen of Hylomyrma dolichops (MCZ35419). A) frontal view; B) dorsal view; C) lateral view. Photos by M.A. Ulysséa.

FIGURE 80. Types of setae found in the species of Hylomyrma. Unbranched setae: A) Hylomyrma adelae, H. blandiens, H. macielae; B) H. immanis; C) H. marielleae. Branched setae: D) H. dentiloba, H. lispectorae, H. mitiae, H. peetersi, H. virginiae; E) H. balzani, H. lopesi; F) H. blandiens, H. jeronimae, H. versuta; G) H. dolichops; H) H. transversa; I) H. longiscapa; J) H. balzani, H. lopesi, H. primavesi, H. reitteri, H. versuta; K) H. plumosa.

FIGURE 85. Distribution records of Hylomyrma columbica, H. marielleae, H. plumosa, and H. reitteri.

FIGURE 87. Distribution records of Hylomyrma dolichops, and H. mitiae.