Hylomyrma peetersi Ulysséa, 2021

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 : 86-90

Hylomyrma peetersi Ulysséa new species

Figures 57 , 80D , 89 (map)

Holotype: GUYANA: [Cuyuni-Mazaruni]: Mt. Ayanganna Falls Camp , 1134m, 59°57.563′W, 5°22.332′N, 11.x.2002, T.R. Schultz, J. LaPolla, C.J. Marshall, R. Williams, 1° forest, litter sample, JSL021011-01-LS06 (1W) (USNMENT00413223) [ USNM]. Paratypes: same data as holotype except JSL021011-01-LS13 (1W) (USNMENT00413369) [ USNM] ; JSL021011-01-LS09 (1W) (USNMENT00413299) [ MZCZ] ; JSL021011-01-LS07 (1W) (USNMENT00413243) [ DZUP] ; JSL021011-01-LS18 (1W) (USNMENT 00413433) [ MZSP 67407 ] ; JSL021011-01-LS14 (1W) (USNMENT00413373 MZHY194) [ MZSP] ; Mt. Ayanganna Base Camp , 732m, 59°55.486′W, 5°20.063′N, 9.x.2002, J.S. LaPolla, forest, litter sample, JSL021009-03-LS07 (1W) (USNMENT00441070) [ USNM] ; Mt. Ayanganna Cloud Forest, 1300m, 59°57.969′W, 5°22.483′N, 13.x.2002, T.R. Schultz, J. LaPolla, C.J. Marshall, R. Williams, litter sample, JSL021013-01-LS10 (1W) (USNMENT00413807) [USNM] ; JSL021013-01-LS18 (1W covered with gold, without postpetiole and gaster) (USNMENT 00413896) [ USNM].

Diagnosis. Regular and longitudinal striae on head dorsum diverge towards posterior margin, interspaces between striae smooth, striae crest punctuated; mesosoma covered with regular, longitudinal, parallel and thick striae; longitudinal striae on lateral of pronotum and mesepisternum continuing transversely on propodeum; dorsal margin of petiole continuous, strongly convex; subtriangular projection on mesoventral surface of petiole; node rounded with transverse striae on dorsum; subpostpetiolar process smooth, weak, convex; profemur posterior surface and protibia extensor surface mostly smooth, few striae on basal and apical regions; striation on tergum of first gastral segment restricted to base.

Description. WORKER (n=4) ( Fig. 57A–C ): HL (0.88–0.94); HW (0.84–0.90); ML (0.57–0.60); SL (0.62–0.66); MOD (0.20–0.24); PNW (0.56–0.64); WL (1.14–1.24); PSL (0.16–0.19); PL (0.52–0.59); PW (0.20–0.22); PPL (0.32–0.34); PPW (0.30–0.31); GL (0.98–1.02); TL (4.41–4.71); CI (94.44–96.62); SI (73.33–76.47); OI (23.81– 26.66). Small-sized. Shiny integument. Brownish body, darker gaster, lighter appendices. Thin and branched setae ( Fig. 80D ), long to midsized, suberect to subdecumbent; 2 short branches of unequal size from the main axis.

Head subquadrate; posterior margin straight. Mandible masticatory margin with 5 teeth. Anterior margin of clypeus straight medially, with a pair of small teeth laterally; median area of clypeus with 8–9 striae, longitudinal, regular to irregular, converging to a point on the anterior margin, interspaces distinguishable. Frontal triangle with 3 striae. Short scape, not reaching head posterior margin; apical antennomere of similar size or slightly shorter than previous 3 antennomeres together. Frontal carina straight. Eye drop-shaped, small-sized, larger diameter with 10 ommatidia. Regular and longitudinal striae on head dorsum, divergent towards posterior margin, striae with punctuated crests, interspaces smooth. Head laterodorsal sculpture converges to mandible insertion region; head lateral sculpture converges to eye margin; gena striate, 2–3 regular and semicircular striae circumscribe the torulus, not reaching eye margin. Interspaces between striae on head ventral surface distinguishable.

Mesosoma covered with regular and longitudinal striae, thicker than head striation, transverse on pronotum anterior region (DV), longitudinal in other regions (DV); longitudinal striae on lateral of pronotum and mesepisternum continuing transversely on propodeum. Promesonotal junction and metanotal groove indistinct. Transverse carina well-marked. Dorsal margin of mesosoma continuous, convex. Propodeal lobe bidentate, dorsal tooth longer and rounded tip; ventral tooth shorter and blunt; dorsal tooth length similar to propodeal spine length. Propodeal spine short, straight (LV), divergent (DV), sculptured on base. Procoxa striae of uniform thickness; irregular and transverse striae on C2 and C3. Profemur and protibia mostly smooth, few striae on basal and apical regions.

Dorsal margin of petiole continuous, strongly convex; subtriangular projection on mesoventral surface of petiole; ventral surface smooth; first third of dorsal surface smooth, transverse striae on posterodorsal surface continuing on lateral surface forming arches. Longitudinal striae on postpetiole; subpostpetiolar process smooth, weak, convex.

Tergum first gastral segment striation similar to postpetiole striae, short, restricted to base, striae length equivalent to 1 / 2 of postpetiole length; sternum smooth.

QUEEN Unknown.

MALE Unknown.

Etymology. The epithet peetersi is a Latin noun in the genitive case created by adding the singular Latin genitive case suffix -i to the last name of a male person. This species is named in honor of our friend and colleague Dr. Christian Paul Peeters (1956–2020), a Belgian born researcher that worked at the Université Pierre et Marie Curie in Paris, and who contributed enormously to Myrmecology in general and, specifically to the present work, in understanding the Hylomyrma intercastes. Peeters generously received the first author in his lab for some very profitable months in 2015.

Comments. The diagnostic characters of this species are sufficient to distinguish it from most of its congeners. Hylomyrma peetersi is, however, more similar to H. margaridae and H. villemantae . All three species display a strongly convex petiole, with indistinguishable petiolar peduncle and node, and the body mainly covered with regular and longitudinal striae. Hylomyrma peetersi and H. margaridae can be easily distinguished from H. villemantae (characteristic in parenthesis) by the striae on the head dorsum with punctuated crests (vs. with smooth crests), the mesosoma longitudinally striate (vs. with few elliptic and concentric striae), the shorter propodeal spine (vs. longer), the armed mesoventral surface of petiole (vs. unarmed), and the longitudinal striae on the dorsum of postpetiole and gaster (vs. smooth). Hylomyrma peetersi can be distinguished from H. margaridae in the striae on the laterals of mesosoma that are directed transversely to the propodeal dorsum (vs. directed to the propodeal spine), the mesoventral surface of petiole armed with a subtriangular projection (vs. a conspicuous spine), the petiolar dorsum entirely covered with transverse striae (vs. with both transverse and longitudinal striae), and the weak subpostpetiolar process (vs. prominent). All three species are allopatric; H. villemantae is recorded in Brazil (BA) ( Fig. 86 ), whereas H. peetersi and H. margaridae occur in relatively close areas in northern South America (French Guiana, Guyana, and Venezuela) ( Fig. 89 ).

Distribution. The specimens were collected in areas near the Guyana - Venezuela border ( Fig. 89 ).

Natural history. This species inhabits the leaf-litter of forested areas at elevations between 732 and 1200 m.

Additional material examined (2 workers): VZLA[ VENEZUELA]: Bolívar: km114 El Dorado to Santa Elena , 12.viii.1986, 1000m, 6°01′N, 61°24′W, P.S. Ward [leg.], #8548-16, sifted litter (leaf mold, rotten wood), rainforest (1W) [ MIZA]; same except 1200m (1W) [ MIZA] .

Hylomyrma plumosa Pierce, Branstetter & Longino, 2017

Figures 58 , 80F, 80K , 85 (map)

Hylomyrma plumosa Pierce, Branstetter & Longino, 2017: 138 (W). Holotype: COSTA RICA: Limón: Res. Biol. Hitoy-Cerere , 9.66480 -83.02346 ± 10 m, 250 m [a.s.l.], 10 June 2015, [Project] ADMAC [collection code] #Wa-E-02-2-38, tropical rainforest, ex sifted leaf litter (1W) ( CASENT0638700 ) [ CASC] [examined by image]. Paratypes: same data as holotype (1W) ( CASENT0638687 ) [ MCZC] [not examined] ; (1W) ( CASENT0638688 ) [ UCD] [not examined] ; (1W) ( CASENT0638693 ) [ UCR] [not examined] ; (1W) ( CASENT0638697 ) [ USNM] [not examined] ; (1W) ( CASENT0638703 MZSP67408 ) [ MZSP] [examined] ; (8W) ( CASENT0638720 , CASENT0638701 , CASENT0638725 , CASENT0638698 , CASENT0638700 , CASENT0638722 , CASENT0638724 , CASENT0638735 ) [ JTLC] [not examined].

Worker ( Fig. 58 A-C) Diagnosis. Mesosoma and petiole covered with thin striae (microsculpture) superimposed on irregular and thick striae (macrosculpture), interspaces between thinner striae indistinguishable; conspicuous and trifid setae.

QUEEN Unknown.

MALE Unknown.

Etymology. The specific epithet is a reference to the distinctive branched setae of this species.

Comments. Hylomyrma plumosa is identified based on the conspicuous and trifid setae ( Fig. 80K ). This species resembles H. versuta , described by Kempf (1973) as “long hairs, pointed at tip, gently curved on petiole and postpetiole”. However, the types of H. versuta and additional examined material comprise specimens with unbranched and branched setae. The branched setae of H. versuta , mostly present on the petiole, postpetiole, and gaster, are composed of a variable number of short branches with similar size ( Fig. 80F ). These branched setae are not conspicuous as in H. longiscapa , H. plumosa , and H. transversa , being better observed in SEM images.

Hylomyrma plumosa and H. versuta are locally sympatric ( Figs. 85 , 88 ), having been collected in the same sample (ALAS #03/WF/02/) near La Virgen (300 m), and in different samples ( H. plumosa #AMI-1-W-006-01, and H. versuta #AMI-1-W-006-05) from the La Selva Biological Station (50 m); both locations in Heredia Province, Costa Rica. The two species have very similar body sculpture. The difference between them is very subtle: the propodeum is laterally covered by thin striae (microsculpture) with indistinguishable interspaces superimposed on irregular and thick striae (macrosculpture) in Hylomyrma plumosa , whereas H. versuta presents thin striae (microsculpture) with indistinguishable interspaces between irregular and thick striae (macrosculpture). Initially, we understood that H. plumosa and H. versuta belonged to a continuum of variation due to their body sculpture similarity, variable setae, and co-occurrence. But molecular data show H. plumosa as sister to the H. cf. dentiloba sp.2 (the true H. dentiloba )– H. versuta clade ( Pierce et al. 2017). In this scenario, we have decided to maintain all three species as valid until additional evidence is gathered. Further investigative approaches using UCEs should include representatives of all the variation found in these taxa (or nominal species).

Distribution. Hylomyrma plumosa occurs in Costa Rica ( Fig. 85 ).

Natural history. This species occurs in wet forests at elevations between 50 and 300 m. Seventeen specimens were collected in the leaf-litter, which suggests that this species nests in fallen logs, rotten wood, between leaves, or inside natural cavities of the superficial soil layers.

Additional material examined (4 workers): COSTA RICA: Heredia : 11km ESE La Virgem, 10.35, -84.05 + 2km, 300m, 10.iv.2004, ALAS #03/WF/02/all montane wet forest, ex sifted leaf litter (1W) [ MZSP]; La Selva, E. O Wilson col., 19.iii.85 (1W) [ MCZC]; La Selva Biological Station , 10.41639, -84.02 + 500m, 50m, 16.iii.2004, TEAM #AMI-1-W-006-01, mature wet forest, ex sifted leaf litter (2W) ( MZSP67470 , MZHY84) [ MZSP] .

Hylomyrma plumosa Pierce, Branstetter & Longino, 2017

Figures 58 , 80F, 80K , 85 (map)

Hylomyrma plumosa Pierce, Branstetter & Longino, 2017: 138 (W). Holotype: COSTA RICA: Limón: Res. Biol. Hitoy-Cerere , 9.66480 -83.02346 ± 10 m, 250 m [a.s.l.], 10 June 2015, [Project] ADMAC [collection code] #Wa-E-02-2-38, tropical rainforest, ex sifted leaf litter (1W) ( CASENT0638700 ) [ CASC] [examined by image]. Paratypes: same data as holotype (1W) ( CASENT0638687 ) [ MCZC] [not examined] ; (1W) ( CASENT0638688 ) [ UCD] [not examined] ; (1W) ( CASENT0638693 ) [ UCR] [not examined] ; (1W) ( CASENT0638697 ) [ USNM] [not examined] ; (1W) ( CASENT0638703 MZSP67408 ) [ MZSP] [examined] ; (8W) ( CASENT0638720 , CASENT0638701 , CASENT0638725 , CASENT0638698 , CASENT0638700 , CASENT0638722 , CASENT0638724 , CASENT0638735 ) [ JTLC] [not examined].

Worker ( Fig. 58 A-C) Diagnosis. Mesosoma and petiole covered with thin striae (microsculpture) superimposed on irregular and thick striae (macrosculpture), interspaces between thinner striae indistinguishable; conspicuous and trifid setae.

QUEEN Unknown.

MALE Unknown.

Etymology. The specific epithet is a reference to the distinctive branched setae of this species.

Comments. Hylomyrma plumosa is identified based on the conspicuous and trifid setae ( Fig. 80K ). This species resembles H. versuta , described by Kempf (1973) as “long hairs, pointed at tip, gently curved on petiole and postpetiole”. However, the types of H. versuta and additional examined material comprise specimens with unbranched and branched setae. The branched setae of H. versuta , mostly present on the petiole, postpetiole, and gaster, are composed of a variable number of short branches with similar size ( Fig. 80F ). These branched setae are not conspicuous as in H. longiscapa , H. plumosa , and H. transversa , being better observed in SEM images.

Hylomyrma plumosa and H. versuta are locally sympatric ( Figs. 85 , 88 ), having been collected in the same sample (ALAS #03/WF/02/) near La Virgen (300 m), and in different samples ( H. plumosa #AMI-1-W-006-01, and H. versuta #AMI-1-W-006-05) from the La Selva Biological Station (50 m); both locations in Heredia Province, Costa Rica. The two species have very similar body sculpture. The difference between them is very subtle: the propodeum is laterally covered by thin striae (microsculpture) with indistinguishable interspaces superimposed on irregular and thick striae (macrosculpture) in Hylomyrma plumosa , whereas H. versuta presents thin striae (microsculpture) with indistinguishable interspaces between irregular and thick striae (macrosculpture). Initially, we understood that H. plumosa and H. versuta belonged to a continuum of variation due to their body sculpture similarity, variable setae, and co-occurrence. But molecular data show H. plumosa as sister to the H. cf. dentiloba sp.2 (the true H. dentiloba )– H. versuta clade ( Pierce et al. 2017). In this scenario, we have decided to maintain all three species as valid until additional evidence is gathered. Further investigative approaches using UCEs should include representatives of all the variation found in these taxa (or nominal species).

Distribution. Hylomyrma plumosa occurs in Costa Rica ( Fig. 85 ).

Natural history. This species occurs in wet forests at elevations between 50 and 300 m. Seventeen specimens were collected in the leaf-litter, which suggests that this species nests in fallen logs, rotten wood, between leaves, or inside natural cavities of the superficial soil layers.

Additional material examined (4 workers): COSTA RICA: Heredia : 11km ESE La Virgem, 10.35, -84.05 + 2km, 300m, 10.iv.2004, ALAS #03/WF/02/all montane wet forest, ex sifted leaf litter (1W) [ MZSP]; La Selva, E. O Wilson col., 19.iii.85 (1W) [ MCZC]; La Selva Biological Station , 10.41639, -84.02 + 500m, 50m, 16.iii.2004, TEAM #AMI-1-W-006-01, mature wet forest, ex sifted leaf litter (2W) ( MZSP67470 , MZHY84) [ MZSP] .

Figures

FIGURE 57. Holotype worker of Hylomyrma peetersi (USNMENT00413223). A) frontal view; B) dorsal view; C) lateral view. Photos by Ricardo Kawada.

FIGURE 58. Holotype worker of Hylomyrma plumosa (CASENT0638700). A) frontal view; B) dorsal view; C) lateral view. Photos by Michele Esposito, available from www.antweb.org.

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 86. Distribution records of Hylomyrma dentiloba, H. macielae, H. reginae, H. villemantae, and H. wachiperi.

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

FIGURE 89. Distribution records of Hylomyrma lopesi, H. margaridae, H. peetersi, H. transversa, and H. virginiae.