Sericomyrmex parvulus

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Sericomyrmex parvulus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Sericomyrmex
Species: S. parvulus
Binomial name
Sericomyrmex parvulus
Forel, 1912

Sericomyrmex parvulus usnment01124296 p 1 high.jpg

Sericomyrmex parvulus usnment01124296 d 1 high.jpg

Specimen Labels

Synonyms

Most collections of this species have been from forested areas. The biology of Sericomyrmex parvulus has not been studied, general details about the biology of the genus are given here.

Identification

Ješovnik & Schultz (2017) - Small species; posterior cephalic corner smoothly rounded; frontal lobe triangular, small, narrow; frontal carina faint, incomplete; mesosomal tubercles small, low, first gastral tergite with lateral carinae weakly developed, dorsal carinae absent.

The aptly named S. parvulus is the smallest Sericomyrmex species. In the regions where their distributions overlap, parvulus is most easily mistaken for Sericomyrmex opacus. In general opacus is larger, with wider, rectangular frontal lobes. Similarly, the S. opacus queen can be separated from the parvulus queen by its slightly larger size and by the presence of supraocular eye carinae in some specimens (absent in parvulus). The queen of Sericomyrmex saramama is similar in size but can be recognized by its striate mandibles (smooth in parvulus).

Within-species morphological variation in S. parvulus includes the frontal carinae (typically incomplete and faint, but complete and stronger in some populations), eyes (sometimes covered with a white layer, but sometimes not), and the general robustness of denticles and tubercles on the mesosoma and metasoma.

Keys including this Species

Distribution

Ješovnik & Schultz (2017) - Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname.

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality), Guyana, Suriname (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castano-Meneses et al (2017) - The springtail species Cyphoderus agnotus Börner (Cyphoderidae: Cyphoderus) and Cyphoderus similis Börner (Cyphoderidae: Cyphoderus) are known from nests of this ant.

Castes

Figure 48.
Figure 49.

Jesovnik and Schultz 2017. Figure 48. S. parvulus worker and queen; head, lateral profile, and dorsal view. Worker (USN-MENT00446157) (a, c, e). Queen (USNMENT01125594) (b, d, f). Figure 49. S. parvulus worker (USNMENT01125593), SEM images. a Head, full-face view b mandibles c mesosoma and metasoma, lateral view d eye.

Figure 50.

Jesovnik and Schultz 2017. Figure 50. S. parvulus larva (USNMENT01125592), SEM images. a Lateral view b ventral view c head, frontodorsal view d head, lateral view e mouthparts f anal setae.

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • parvulus. Sericomyrmex parvulus Forel, 1912e: 193 (w.) BRAZIL.
    • Ješovnik & Schultz, 2017a: 82 (q.l.).
    • Status as species: Wheeler, W.M. 1916c: 11 (in key); Emery, 1924d: 339; Borgmeier, 1927c: 128; Kempf, 1972a: 229; Bolton, 1995b: 382; Ješovnik & Schultz, 2017a: 80 (redescription).
    • Senior synonym of myersi: Ješovnik & Schultz, 2017a: 80.
  • myersi. Sericomyrmex myersi Weber, 1937: 400 (w.) SURINAM.
    • Status as species: Weber, 1946b: 143; Kempf, 1972a: 229; Bolton, 1995b: 382.
    • Junior synonym of parvulus: Ješovnik & Schultz, 2017a: 80.

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

Ješovnik & Schultz (2017) - In populations of S. opacus from southern Colombia and northwestern Brazil, some of the workers have small, triangular frontal lobes, making them easy to mistake for parvulus. They are usually larger than the typical parvulus worker, but given the overlap in size between the two species, they could be mistaken for larger parvulus workers. It is possible that these intermediate individuals are hybrids and that the molecular and morphological differences between the Colombian and Brazilian populations of opacus are a consequence of hybridization and introgression with parvulus.

Description

Ješovnik & Schultz (2017):

Worker

(lectotype): HWe 0.66–0.9 (0.9) HW 0.66–0.93 (0.93) HW1 0.6–0.93 (0.84) HW2 0.68–1.03 (0.93) HW3 0.48–0.8 (0.6) IFW1 0.42–0.65 (0.62) IFW2 0.15–0.28 (0.26) HL1 0.62–0.9 (0.88) HL2 0.58–0.82 (0.8) SL 0.48–0.72 (0.64) EL 0.11–0.15 (0.15) Om 6–9 WL 0.74–1.23 (1.23) PL 0.16–0.34 (0.25) PPL 0.13–0.24 (0.16) GL 0.6–0.9 (0.83) HFL 0.65–0.99 (0.92) PW 0.46–0.64 (0.62) CI 94–106 (103) FLI 60–75 (69) SI 64–78 (71) OI 13–19 (17) CEI 5–12 (8) [N=55]

Pilosity. Pubescence dense, lighter than integument, appressed to decumbent. Hairs moderately thick, relatively sparse, often curved, yellow to gray, appressed to suberect.

Head. In full-face view evenly broad and long (CI=102 ± 3), posterior corner smoothly rounded, posterior cephalic emargination shallow (CEI=9 ± 2), gradually impressed. Vertexal impression faint, frontal tumuli barely visible. Mandible with 7–8 teeth, dorsally smooth and glossy, finely transversely striate only along masticatory margin. Eye medium-sized (OI =16 ± 1), flat to slightly convex, 6–9 ommatidia across largest diameter, in some specimens eyes partially covered with white layer (Figure 6l), in others eyes without white layer. Frontal lobe triangular, relatively small and narrow (FLI=70 ± 3), posterior margin shorter than medial. Frontal carina straight to slightly curved laterally, incomplete, weak, fading before reaching posterior cephalic corner. Antennal scape relatively short, not reaching posterior cephalic corner (SI=71 ± 3).

Mesosoma. Mesosomal tubercles low and obtuse. Propodeal carinae low and weak, with small posterodorsal denticles.

Metasoma. Petiole with two low, reduced dorsal denticles; postpetiole with two faint, short dorsal carina; both best seen in dorsolateral view. First gastral tergite with lateral carinae weakly developed, dorsal carinae faint or absent.

Queen

HWe 0.98–1.05 HW 1–1.08 HW1 1–1.13 HW2 1.08–1.22 HW3 0.74–0.8 IFW1 0.7–0.78 IFW2 0.24–0.28 HL1 0.95–1.08 HL2 0.88–0.95 SL 0.64–0.7 EL 0.21–0.24 Om 14–15 EW 0.08–0.08 WL 1.56–1.65 PL 0.34–0.48 PPL 0.2–0.25 GL 1.4–1.58 HFL 1–1.18 PW 0.82–0.92 CI 95–103 FLI 72–76 SI 66–70 OI 21–23 [N=4]

Head. Mandible with 7–8 teeth, dorsally glossy and smooth, finely transversely striate only along masticatory margin. Preocular carina fading posterior to eye. Eye large (OI=22 ± 1), mildly convex, 14–15 ommatidia across largest diameter. Frontal lobe more robust than in worker, antennal scape not reaching posterior cephalic corner.

Mesosoma. Lateral pronotal tubercles very low. Scutum in dorsal view with notauli and median mesoscutal line absent or very faint. Parapsidal lines faint, slightly curved. Axillae small, groove separating axillae from scutellum smooth. Scutellum short in dorsal view, narrowing posteriorly, posterior margin with V-shaped notch, notch sometimes continuing into median impression that divides scutellum in two lateral parts. Propodeal denticle low, obtuse, laterally flattened, diverging posteriorly in dorsal view.

Metasoma. First tergite of gaster with lateral carinae well developed, dorsal carinae absent or weak, anteromedian groove shallow.

Larva

Lateral and dorsal surfaces without any setae. Supra-antennal setae absent. Four genal setae on each side. Mandibular apical tooth undivided. Labial denticles either absent or small number of denticles present anterior to sericteries. Thoracic segment 1 (T1) ventrally with multidentate spinules. Number of ventral setae: T1, T2, and T3 with two setae each, abdomen without setae (not including anal setae). Single pair of sensilliform setae anterior to anal opening.

Type Material

Lectotype worker (here designated): Brazil, Pará, [-4, -53] C. Emery (Musee d'Histoire Naturelle Genève: 1w, USNM00445579, bottom specimen). Paralectotype: same data as lectotype (MHNG: 1w, USNM00445579, top specimen).

References

  • Castano-Meneses, G., J. G. Palacios-Vargas, J. H. C. Delabie, D. Zeppelini, and C. S. F. Mariano. 2017. Springtails (Collembola) associated with nests of fungus-growing ants (Formicidae: Myrmicinae: Attini) in southern Bahia, Brazil. Florida Entomologist. 100:740-742. doi:10.1653/024.100.0421
  • Forel, A. 1912f. Formicides néotropiques. Part II. 3me sous-famille Myrmicinae Lep. (Attini, Dacetii, Cryptocerini). Mém. Soc. Entomol. Belg. 19: 179-209 (page 193, worker described)
  • Ješovnik, A., Schultz, T.R. 2017. Revision of the fungus-farming ant genus Sericomyrmex Mayr (Hymenoptera, Formicidae, Myrmicinae). ZooKeys, 670, 1–109 (DOI 10.3897/zookeys.670.11839).