Pachycondyla fuscoatra

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Pachycondyla fuscoatra
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Pachycondyla
Species: P. fuscoatra
Binomial name
Pachycondyla fuscoatra
(Roger, 1861)

Pachycondyla fuscoatra casent0281903 p 1 high.jpg

Pachycondyla fuscoatra casent0281903 d 1 high.jpg

Specimen Labels

Most specimens were collected in pitfall traps, a few from Winkler extractions. Otherwise, nothing is known of this rarely collected species (Mackay and Mackay, 2010; Marcineiro & Lattke, 2024).

Identification

Marcineiro & Lattke (2024) - The following suit of characters diagnoses this species:

  1. Frons coarsely striate.
  2. Humeral angle slightly overhanging pronotal side.
  3. Humeral carina not developed.
  4. Petiole with parallel anterior and posterior margins.
  5. Gaster matte

This species is very similar to Pachycondyla striata and Pachycondyla impressa. When compared with MacKay’s description of P. impressa and using his identification key, specimens of P. fuscoatra may also be determined as P. impressa. Examining high resolution images of the types of P. impressa available on AntWeb (FOCOL0951; FOCOL0952; FOCOL0953, photography by Christiana Klingenberg) and comparing them to specimens of P. fuscoatra it becomes clear how these two species differ one from another.

In P. impressa the clypeus is short (CD < antennal scape width) with a strong median concavity in the anterior margin, while in P. fuscoatra it is longer (CD > antennal scape width) and almost straight. The humeral angle of P. impressa is not swollen or elevated, but rounds continuous onto the lateral pronotal face, while in P. fuscoatra it is elevated and developed into a blunt longitudinal ridge but does not form a carina. Both species present a tooth-like metasternal process and costulae on the sides of the pygidium, features formerly considered to be diagnostic for P. impressa (Kempf, 1972; MacKay & MacKay, 2010).

P. fuscoatra does not present a humeral carina, while it is strongly developed and easily visible in P. striata. The petiole of P. fuscoatra is longer (PetI 114–129) than in P. striata (PetI 122–153), and the anterior margin in lateral view is not as curved. The gastral sculpturing of P. fuscoatra is longitudinally strigulate, differing from the matte or sometimes shining punctulate integument of P. striata.

  • Marcineiro & Lattke (2024), Fig. 4: A: Pachycondyla fuscoatra, anterior view of pronotum and posterior head dorsum; B: Pachycondyla impressa, anterior view of pronotum and posterior head dorsum.
  • Marcineiro & Lattke (2024), Fig. 6: A: Pachycondyla fuscoatra, lateral view; B: Pachycondyla striata, lateral view.

There is enormous confusion about this species’ identity, as in the original description Roger (1861) considered it very similar to P. impressa but provided a number of characters to distinguish between the two. Emery (Emery, 1890 apud Kempf, 1961) distinguished between them using integument brightness which “is of reduced systematic value” using Kempf’s words, which are proven true when we examined gaster brightness in P. striata, which varies from matte to shining. Kempf (1961: 195) describes P. fuscoatra as having 5–6 teeth contrasting with 8–9 teeth in P. impressa, but in the original description Roger reports 8 to 9 teeth. MacKay & MacKay (2010) comment on P. fuscoatra having 5 teeth if one ignores the 4 intercalary lesser teeth, leaving P. fuscoatra with 9 teeth. Both Emery and Kempf missed that the humeral angle in P. fuscoatra overhangs the pronotal side in dorsal view, but not in P. impressa, and the dorsum of the pronotum expands after a lateral constriction in front view (Fig. 05). This feature is mentioned in the original description as the pronotum being slightly compressed, but not cited as a differential feature from P. impressa. A compression of the pronotal sides is only observable in Pachycondyla when the humeral angle is developed and overhangs the pronotal sides. We found a specimen from Colombia, deposited in MZSP (MZSP 67240), that was determined as P. fuscoatra by Santschi and also by Borgmeier. This sample is readily identifiable as a specimen of the impressa species complex and has humeral angles developed into blunt longitudinal ridges, with pronotal constrictions as mentioned in the original description of P. fuscoatra. This feature is only observable in P. fuscoatra within this species group, so we agree with the determination of this specimen as P. fuscoatra. The specimen is distinguishable from P. impressa, but is identified and mentioned as P. impressa in Kempf´s work.

Pachycondyla fuscoatra has lateral costulae on the pygidium, but shares this feature with all impressa complex species, reducing its taxonomic value. Nevertheless it is important to take into account for understanding the multiple synonymies and taxonomic confusion (see P. impressa discussion).

Keys including this Species

Distribution

Found from Costa Rica (J. Longino, pers com) to Brazil (latitudinal and longitudinal ranges). Within Brazil found from Pará to Acre (latitudinal range) and from Acre to Pará (longitudinal range). This species is most common in the northern states of Brazil. It inhabits Amazon Forest, northern Caatinga, northern Cerrado and northern Atlantic Forest in altitudes that range from 214m to 650m. This species was previously recorded from Brazil only in Óbidos, Pará (Forel, 1907; Kempf 1972) as mentioned by Kempf in his revision of the genus. (Marcineiro & Lattke, 2024)

  • Marcineiro & Lattke (2024), Fig. 20: Distribution map of Pachycondyla fuscoatra examined specimens.

Latitudinal Distribution Pattern

Latitudinal Range: 9.280833333° to 4.694°.

 
North
Temperate 		North
Subtropical 		Tropical South
Subtropical 		South
Temperate

Distribution based on Regional Taxon Lists

Neotropical Region: Bolivia, Brazil, Colombia (type locality), Costa Rica, Ecuador, Venezuela.

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.
pChart

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.
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Habitat

Specimens are found in mature and secondary rain forest, 1500 - 2050 meters elevation. (Mackay and Mackay 2010)

Biology

Association with Other Organisms

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Nematode

  • This species is a host for the nematode Mermithidae (unspecified "Mermix") (a parasite) in Neotropics (Wheeler, 1928; Laciny, 2021).

Castes

  • Marcineiro & Lattke (2024), Fig. 19: Pachycondyla fuscoatra (DZUP 548857) worker. A: head in full-face view; B: full body in dorsal view; C: full body in lateral view.

Nomenclature

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

  • fuscoatra. Ponera (Pachycondyla) fuscoatra Roger, 1861a: 8 (w.) COLOMBIA, VENEZUELA.
    • Type-material: syntype workers (number not stated).
    • Type-localities: Colombia (no further data), and Venezuela: Puerto Caballo (no collector’s name).
    • Type-depository: MNHU.
    • Mackay & Mackay, 2010: 339 (q.).
    • Combination in Pachycondyla (Pachycondyla): Emery, 1901a: 45;
    • combination in Pachycondyla: Mayr, 1863: 439; Roger, 1863b: 18; Schmidt, C.A. & Shattuck, 2014: 155.
    • Status as species: Roger, 1863b: 18; Mayr, 1863: 439; Emery, 1890a: 58, 71 (in key); Emery, 1890b: 42; Dalla Torre, 1893: 34; Forel, 1899c: 12; Emery, 1901a: 48; Emery, 1904b: 596; Forel, 1907e: 1; Emery, 1911d: 74; Forel, 1912c: 39; Santschi, 1913h: 34; Wheeler, W.M. 1925a: 5; Kempf, 1961c: 193; Kempf, 1972a: 174; Bolton, 1995b: 305; Mackay & Mackay, 2010: 339 (redescription); Feitosa, 2015c: 99; Fernández & Guerrero, 2019: 541.
    • Distribution: Colombia, Venezuela.
    • [Note: Mackay & Mackay, 2010: 342, point out that, “previous records of this species, ranging from Costa Rica south to Bolivia, are apparently misidentifications of P. impressa.”]

Type Material

Description

Worker

From Mackay and Mackay (2010): The worker of this species is a large (total length 13 mm) black ant with partially brown appendages. The mandibles are long with 5 or 6 well-developed teeth, as well as 4 or 5 smaller teeth or denticles. The anterior border of the clypeus is broadly rounded and slightly concave medially. The head length is 2.7 mm; the head width is 2.6 mm. The malar carina is absent and the eye is relatively small (maximum diameter 0.35 mm) located slightly more than one eye diameter from the anterior margin of the head. The scape (2.3 mm) extends slightly past the posterior lateral corner of the head. The sides of the head are nearly straight and slightly diverge anteriorly; the posterior border is strongly concave. The pronotal shoulder is rounded with little evidence of a swelling; the metanotal suture is poorly marked on the dorsum of the mesosoma and does not break the sculpture and the propodeal spiracle is slit-shaped. The anterior and posterior faces of the petiole are nearly parallel and the dorsal face is well developed, the anterior face is slightly concave, the posterior face convex. The subpetiolar process is poorly developed and consists of a swollen region, sometimes with a tiny anterior ventrally directed tooth. The anterior face of the postpetiole is slightly concave and meets the dorsal face and nearly a right angle. The stridulatory file is absent on the second pretergite, as are the arolia between the tarsal claws.

Erect hairs are present on the mandibles, clypeus, dorsal and ventral surfaces of the head, scape, dorsum of the mesosoma, petiole and all surfaces of the gaster; most hairs on the legs are suberect. Appressed pubescence is sparse, but present on the head, the mesosoma and the gaster.

The entire dorsum of the head is covered with coarse striae or rugae, which extend on the sides well past the eyes. The anterior ½ of the pronotum has transverse striate and is partially smooth and glossy, the posterior ⅔ has longitudinal striae; most of the striae on the dorsum of the mesonotum and propodeum are longitudinal, those on the posterior face of the propodeum are transverse, with much of the surface shining, the sides of the mesosoma have mostly longitudinal striae. The side of the petiole has poorly defined horizontal striae, which partially cover the posterior face of the petiole, at least near the apex, the top of the petiole has transverse striae and the gaster is smooth and glossy with scattered punctures.

Queen

From Mackay and Mackay (2010): The female (undescribed) is larger than the worker (total length 15 mm) black with partially brown appendages. The mandible has five well-developed teeth with four smaller teeth spaced between them. The clypeus is broadly rounded, the sides of the head converge anteriorly and the posterior border is strongly concave. The head length is 3.3 mm; the head width is 3.4 mm. The eye is moderately large (maximum diameter 0.9 mm) located less then one diameter from the anterior margin of the head (seen from the side). The scape is relatively short (2.8 mm) and does not reach the posterior lateral corner of the head. The pronotal shoulder is slightly swollen but does not form a carina. The propodeal spiracle is slit-shaped; the petiole and gaster are similar to those of the worker.

The pilosity and sculpture are similar to those of the worker.

Male

Males are not known for this species.

Type Material

Mackay and Mackay (2010) - Colombia (without locality) and Venezuela, Puerto Cabello (apparently misspelled as Caballo).

Etymology

The name of this species is based on two Latin words, fuscus, meaning dark and atra, meaning black, referring to the color. (Mackay and Mackay 2010)

References

References based on Global Ant Biodiversity Informatics

  • Emery C. 1890. Voyage de M. E. Simon au Venezuela (Décembre 1887 - Avril 1888). Formicides. Annales de la Société Entomologique de France (6)10: 55-76.
  • Emery C. 1904. Zur Kenntniss des Polymorphismus der Ameisen. Zoologische Jahrbücher. Supplement 7: 587-610.
  • Fernández F., and T. M. Arias-Penna. 2008. Las hormigas cazadoras en la región Neotropical. Pp. 3-39 in: Jiménez, E.; Fernández, F.; Arias, T.M.; Lozano-Zambrano, F. H. (eds.) 2008. Sistemática, biogeografía y conservación de las hormigas cazadoras de Colombia. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xiv + 609 pp.
  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • Kempf W. W. 1961. As formigas do gênero Pachycondyla Fr. Smith no Brasil (Hymenoptera: Formicidae). Revista Brasileira de Entomologia 10: 189-204.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kusnezov N. 1953. La fauna mirmecológica de Bolivia. Folia Universitaria. Cochabamba 6: 211-229.
  • Salinas P. J. 2010. Catalogue of the ants of the Táchira State, Venezuela, with notes on their biodiversity, biogeography and ecology (Hymenoptera: Formicidae: Amblyioponinae, Ponerinae, Proceratiinae, Myrmicinae, Ecitoninae, Formicinae, Pseudomyrmecinae, Dolichoderinae). Boletín de la SEA 47: 315-328.
  • Wheeler W. M. 1925. Neotropical ants in the collections of the Royal Museum of Stockholm. Arkiv för Zoologi 17A(8): 1-55.
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