Hylomyrma villemantae

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Hylomyrma villemantae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Pogonomyrmecini
Genus: Hylomyrma
Species: H. villemantae
Binomial name
Hylomyrma villemantae
Neves & Lacau, 2018

Hylomyrma villemantae F1.jpg

Hylomyrma villemantae F5.jpg

Only known from the type locality, a remnant tropical mountain rainforest (Floresta Ombrófila Densa Montana) in Southwestern Bahia, Brazil.

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).

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil.


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

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.).

Castes

Worker

Neves et al. (2018). Plate 1. Hylomyrma villemantae. Figure 3. Detail of the left eye, head in lateral view (holotype worker, [LBSA_ SA_14015869]).
Neves et al. (2018). Plate 2. Hylomyrma villemantae. Figure 4. Mesosoma, left lateral view (holotype worker, [LBSA_SA_14015869]).
Neves et al. (2018). Plate 3. Hylomyrma villemantae. Figure 6. Third and fourth abdominal segments, dorsal view (holotype worker, [LBSA_SA_14015869]). Figure 7. Second and third abdominal segments, lateral view (holotype worker, [LBSA_SA_14015869]). Figure 8. Anterior margin of clypeus and mandibles, dorsal view (paratype worker, [LBSA_SA_14011273]).

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • villemantae. Hylomyrma villemantae Neves & Lacau, in Neves et al., 2018: 203, figs. 1-3 (w.) BRAZIL.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

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 Centro de Pesquisas do Cacau 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 Museu de Zoologia da Universidade de Sao Paulo ([LBSA_ SA_14016100], [LBSA_SA_14016101], [LBSA_SA_14 016102]) and Museu Paraense Emilio Goeldi ([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] Museu de Zoologia da Universidade de Sao Paulo ([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.

References