Hylomyrma villemantae

Only known from the type locality, a remnant tropical mountain rainforest (Floresta Ombrófila Densa Montana) in Southwestern Bahia, Brazil (Neves & Lacau, 2018). Ulyssea & Brandao (2021) note that the biology of this species remains unknown. Type specimens were collected in leaf-litter with winkler extractors, at elevations between 951 and 1070 m in the region known as “Serra das Piabas”, a fragment of Atlantic forest in the Brazilian state of Bahia.

Identification
Neves et al. (2018) - The worker morphology of this new species exhibits all the diagnostic characters of the genus Hylomyrma sensu Kempf (1973). It differs from all other known species by a unique combination of characters:
 * 1. Head in dorsal view with a subquadrate shape (CI 90.9±2.21).
 * 2. Eyes medium-sized, their maximum diameter with about 12 ommatidia, being less than two times longer than minimum diameter, and strongly shorter than one fourth of head length.
 * 3. Eyes with anterior border broadly rounded, not drawn out into a blunt point.
 * 4. Scape sharply bent at base.
 * 5. Scape relatively short, its apex not reaching the vertexal border, and its length less than the maximum head width (SI 71.63±2.88).
 * 6. Propodeal spines well developed, needle like, much longer than width of petiolar node.
 * 7. Metafemur length shorter than maximum head length (MFI 85.61±3.33).
 * 8. Abdominal segment 2 (petiole) in lateral view with a long anterior peduncle (more than twice as long as high), followed by a well differentiated node which anterior and dorsal faces are separated by a rounded, nearly right angle.
 * 9. Abdominal sternite 2 in lateral view with outline not differentiating any tooth.
 * 10. Abdominal tergite 3 (postpetiole) in lateral view with outline of dorsal face differentiating a continuous convexity (wide and weak), not truncated posteriorly.
 * 11. Head dorsum entirely covered by longitudinal, thick and well-marked costae, smooth and shining, and regularly interspaced by narrow and deep sulci.
 * 12. Mesosoma with dorsum and lateral faces covered by longitudinal, thick and well-marked costae, smooth and shining, and regularly interspaced by narrow and deep sulci.
 * 13. Pronotum with posterior margin of neck covered by longitudinal thick and well-marked costae, smooth and shining, and regularly interspaced by narrow and deep sulci.
 * 14. Propodeum with dorsal and posterior faces covered by transversal, thick and well-marked costae, smooth and shining, and regularly interspaced by narrow and deep sulci.
 * 15. Pronotum with anterior sloping face covered by transversal, thick and well-marked costae, smooth and shining, and regularly interspaced by narrow and deep sulci.
 * 16. Outer faces of pro- and meso thoracic coxae sculptured with transversal, straight, regularly spaced, well-marked carinae.
 * 17. Pronotum with anterior margin of neck sculptured with transversal, straight, regularly spaced, well-marked carinulae.
 * 18. Abdominal tergite 2 (petiole) with nearly all surface of dorsal face smooth and shining, except the posterior part bearing superficial, transversal carinulae.
 * 19. Abdominal sternite 2 (petiole) with ventral surface of petiolar node smooth and shining.
 * 20. Abdominal tergite 3 (postpetiole) entirely smooth and shining (without any dense punctuations, nor longitudinal carinulae).
 * 21. Abdominal tergite 4 entirely smooth and shining (without any dense punctuations, nor longitudinal carinulae).
 * 22. Tibiae with extensor face smooth and shining.
 * 23. Fore femora with posterior face smooth and shining.
 * 24. All body surfaces without any plumose or multibranched setae.
 * 25. Gaster with hairs sharpened at tip.
 * 26. Gaster with hairs nearly as long as or longer than width of hind tibiae.

Easily distinguished from any other one in the genus. Hylomyrma villemantae is the sole species in the genus to have an entirely smooth and shining abdominal tergite 4 (character 21). By using the taxonomic identification key of Kempf (1973), at dichotomy 1, Hylomyrma villemantae differs from Hylomyrma immanis by its diagnostic characters 10 (differences in the shape of abdominal segment 3), as well as 11 and 21 (differences in the sculpture pattern of head and metasoma). Moreover, Hylomyrma villemantae also differs from this species by its diagnostic characters 8 (difference in the shape of abdominal segment 2) and 20 (difference in the sculpture pattern of abdominal segments 3 and 4).

Also, at dichotomy 2, Hylomyrma villemantae differs from Hylomyrma longiscapa and Hylomyrma transversa Kempf, 1973 by its diagnostic characters 24 (absence of any plumose or multibranched setae). Moreover, Hylomyrma villemantae also differs from Hylomyrma longiscapa by its diagnostic characters 5, 7 and 8 (differences in the shape of head, mesosoma and metasoma), as well as 12, 18, 19, 20 and 21 (differences in the sculpture pattern of mesosoma and metasoma). Moreover, Hylomyrma villemantae also differs from Hylomyrma transversa by its diagnostic characters 8 (differences in the shape of abdominal segment 2), as well as 12, 18, 19, 20 and 21 (differences in the sculpture pattern of mesosoma and metasoma).

Finally, Hylomyrma villemantae cannot be any one of the species keyed at dichotomy 4: Hylomyrma praepotens; Hylomyrma dolichops; Hylomyrma columbica; Hylomyrma blandiens; Hylomyrma dentiloba; Hylomyrma sagax; Hylomyrma versuta; Hylomyrma reitteri and Hylomyrma balzani because of its diagnostic character 21 (abdominal tergite 4 entirely smooth and shining). Moreover, Hylomyrma villemantae differs from Hylomyrma columbica by its diagnostic characters 1 (difference in the shape of head), as well as 11, 12, 18 and 20 (differences in the sculpture pattern of head, mesosoma and metasoma). Also, Hylomyrma villemantae also differs from Hylomyrma blandiens by its diagnostic characters 3 and 8 (differences in the shape of head and metasoma), as well as 18, 19 and 20 (differences in the sculpture pattern of metasoma). Hylomyrma villemantae also differs from Hylomyrma dentiloba, Hylomyrma versuta and Hylomyrma sagax by its diagnostic characters 8 (differences in the shape of abdominal segment 2), as well as11, 12, 18 and 20 (differences in the sculpture pattern of head, mesosoma and metasoma). Likewise, Hylomyrma villemantae also differs from Hylomyrma praepotens and from Hylomyrma dolichops by its diagnostic characters 8 (differences in the shape of abdominal segment 2), as well as 18, 19 and 20 (differences in the sculpture pattern of metasoma). Furthermore, Hylomyrma villemantae also differs from Hylomyrma reitteri and Hylomyrma balzani by its diagnostic characters 11, 12, 18 and 20 (differences in the sculpture pattern of head, mesosoma and metasoma).

Ulyssea & Brandao (2021) - Regular and longitudinal striae on head dorsum diverge towards posterior margin, interspaces between striae smooth, striae crest smooth; mesosoma covered with concentric and elliptical, regular and thick striae; longitudinal striae on lateral of pronotum and mesepisternum in part continuing transversely on propodeum and in part continuing on propodeal spine; transverse carina inconspicuous; propodeal spine midsized; dorsal margin of petiole continuous, strongly convex, mesoventral surface unarmed; petiole, postpetiole, subpostpetiolar process, profemur posterior surface, protibia extensor surface and tergum of first gastral segment smooth; subpostpetiolar process weak, convex.

The diagnostic characters of this species are sufficient to easily distinguish it from most of its congeners. Still, H. villemantae is very similar to Hylomyrma peetersi and Hylomyrma margaridae. All three species have a strongly convex petiole, with indistinguishable petiolar peduncle and node, and the body mainly covered with regular and longitudinal striae. Even so, H. villemantae can be easily distinguished from both (characteristic in parenthesis) in the striae on the head dorsum with smooth crests (vs. with punctuated crests), the mesosoma with few elliptical and concentric striae (vs. longitudinally striate), the longer propodeal spine (vs. shorter), the unarmed mesoventral surface of petiole (vs. armed), and the smooth dorsum of postpetiole and gaster (vs. with longitudinal striae).

All three species are allopatric; H. villemantae is recorded from 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 based on Regional Taxon Lists
Neotropical Region: Brazil.

Biology
Neves et al. (2018) - Hylomyrma villemantae is only known from the type locality. The area is a relatively large (~400 ha) isolated remnant of tropical mountain rainforest on the top of the mountain “Serra das Piabas” (1070m alt. max.) in Ibicuí municipality, southwest Bahia state, Brazil. This mountain is part of the geographical relief unit known as “Colinas e Cristas pré-litorâneas” (Instituto Brasileiro de Geografia e Estatística [IBGE], 2006). In this region, remnant blocks of native vegetation (ombrophilous forests) are found at higher elevations along with larger pastures and cocoa plantations.

The specimens were found in 24 of 62 leaf-litter samples (1 m²), using Winkler traps. The samples in which they occurred also contained from 5 to 15 other ant species (Neves et al., unpub.). This suggests that the species is relatively abundant in the type locality and that colonies may nest in the leaf-litter. In the type locality, 71 ants species were collected with Hylomyrma villemantae in the 50 Winkler traps during a 2008 expedition (Neves et al., unpub.).

Nomenclature

 * . Hylomyrma villemantae Neves & Lacau, in Neves, Jahyny, et al. 2018: 203, pl. 1, figs. 1-3, pl. 2, figs. 4, 5, pl. 3, figs. 6-8 (w.) BRAZIL (Bahia).
 * Type-material: holotype worker, 44 paratype workers.
 * Type-locality: holotype Brazil: Bahia, Ibicuí, Serra das Piabas, 14°51’57.93’’S, 40°2’34.54’’W, 1070 m., 12.v.2017 (Lacau, Neves, Rocha, Oliveira, Silveira & Rodrigues); paratypes: 10 workers with same data, 6 workers with same data but 2.v.2017, 20 workers with same data but (da Silva, Godinho, Lacau, Prado & Ramos Lacau), 6 workers with same data as last but 29.vi.2008, 2 workers Bahia, Itati, Serra das Piabas, 14°54’50.06’’S, 40°2’9.49’’W, 951 m., 19.xi.2004 (Jahyny, Lacau & Ramos Lacau).
 * Type-depositories: CPDC (holotype); CPDC, LBSA, MPEG, MZSP (paratypes).
 * Status as species: Ulysséa & Brandão, 2021: 121 (redescription)
 * Distribution: Brazil.

Worker
Hereafter, we provide a complement of descriptive elements of the worker morphology of this new species through the presentation of high resolution microphotographs (see figures 1-8 in the taxabox and caste section) and the following morphometric information (data for holotype given in brackets; means with standard deviations for holotype and paratype (n=10) together, given in parenthesis; maximum range for holotype and paratype (n=10) together, given in braces). EL [0,19] (0,20±0,01) {0,17-0,21}, GL [0,9] (0,95±0,10) {0,87-1,17}, HL [0,91] (0,91±0,03) {0,87-0,96}, HW [0,85] (0,83±0,03) {0,79-0,9}, MDL [0,57] (0,56±0,06) {0,51-0,68}, MFL [0,81] (0,78±0,04) {0,7-0,84}, PPH [0,28] (0,26±0,01) {0,25-0,27}, PPL [0,29] (0,29±0,02) {0,27-0,32}, PPW [0,29] (0,27±0,03) {0,2-0,3}, PSL [0,29] (0,28±0,02) {0,25-0,31}, PTH [0,23] (0,22±0,01) {0,21-0,24}, PTL [0,55] (0,55±0,05) {0,48-0,66}, PTW [0,2] (0,20±0,01) {0,18-0,22}, PW [0,59] (0,58±0,04) {0,51-0,63}, SL [0,6] (0,59±0,03) {0,55-0,65}, WL [1,11] (1,12±0,05) {1,05-1,17}. Indices: CI [93,41] (90,62±2,15) {86,0-93,75}, MFI [89,0] (85,23±3,29) {79,6-89,9}, SI [70,6] (71,74±3,03) {68,08-77,5}.

Type Material
Holotype: one worker deposited in deposited in and labeled (data in brackets): [LBSA_ SA_14015869] [Brazil, Bahia, Ibicuí, Serra das Piabas, 14°51’57.93”S, 40° 2’34.54”W, elev. 1070 m] and [Col.: Lacau S., Neves M.S., Rocha I.N., Oliveira M.L., Silveira B.A., Rodrigues F.S., 12.v.2017]. Paratypes (n=44): 10 workers with the same data as holotype, in CPDC ([LBSA_SA_14016086], [ L B S A _ S A _ 1 4 0 1 6 0 8 7 ], [ L B S A _ S A _ 1 4 0 1 6 0 8 8 ] , [LBSA_SA_14016089], [LBSA_SA_14016091], [LBSA_ SA_14016093], [LBSA_SA_14016094], [LBSA_SA_14016095], [LBSA_SA_14016096], [LBSA_SA_14016097]); six workers with the same locality data as holotype and [col.: Lacau S., Neves M.S., Oliveira M.L., Rocha I.N., Silveira B.A., Rodrigues F.S., 02.v.2017] deposited in ([LBSA_ SA_14016100], [LBSA_SA_14016101], [LBSA_SA_14 016102]) and  ([LBSA_SA_14016092], [LBSA_ SA_14016099], [LBSA_SA_14016103]); 20 workers with the same locality data as holotype and [col.: da Silva Jr M.R., Godinho L.B., Lacau S., Prado J.V., Ramos Lacau L.S.,29.vi.2008] in CPDC ([LBSA_SA_14011273], [LBSA_SA_14016104], [LBSA_SA_14016105], [LBSA_ SA_14016109], [LBSA_SA_14016110], [LBSA_SA_ 1401 6111], [LBSA_SA_14016115], [LBSA_SA_14016116], [LBSA_SA_ 14016117], [LBSA_SA_14016118], [LBSA_ SA_14016119], [LBSA_SA_14016120], [LBSA_SA_140 16123], [LBSA_SA_14016124], [LBSA_SA_14016125], [LBSA_SA_14016126], [LBSA_SA_14016128], [LBSA_ SA_14016129], [LBSA_SA_14016162], [LBSA_SA_140 14791]); six workers [Brazil, Bahia, Ibicuí, Serra das Piabas] and [col.: da Silva Jr M.R., Godinho L.B., Lacau S., Prado J.V. e Ramos Lacau L.S., 29.vi.2008]  ([LBSA_SA_14 016106]; [LBSA_SA_14016107]; [LBSA_SA_ 14016108]) and MPEG ([LBSA_SA_14016112]; LBSA_SA_14016113]; [LBSA_SA_14016114]); two workers [Brazil, Bahia, Itati, Serra das Piabas, 14°54’50.06’’S, 40°2’9.49’’W, 951 m alt.] [col. Jahyny B.J., Lacau S., Ramos Lacau L.S., 19.xi.2004] in CPDC ([LBSA_SA_14011396], [LBSA_SA_ 14011397]).

Etymology
This species is named in honor to Dr. Claire Villemant, a French entomologist, curator of the Hymenoptera Collection at Muséum National d’Histoire Naturelle de Paris (MNHN). Insect lover, she devoted her life studying the diversity and taxonomy of hymenopters in many parts of the world, while passing on all her passion to the numerous generations of students she trained. The specific name villemantae is the feminine genitive of her patronymic name.