Leptogenys crudelis

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Leptogenys crudelis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Leptogenys
Species: L. crudelis
Binomial name
Leptogenys crudelis
(Smith, F., 1858)
Synonyms

Leptogenys crudelis P.jpg

Leptogenys crudelis D.jpg

Specimen Label

Nothing is known about the biology of Leptogenys crudelis.

Identification

A member of the crudelis species group.

Lattke (2011) - Eye flat, its length almost one-fourth length of lateral cephalic margin; scape surpasses posterior margin by more than one-third its length. Anterior margin of node in dorsal view less than one-fourth width of posterior margin; constriction between third and fourth abdominal segments well marked.

This species is sympatric with Leptogenys iheringi in Bahia, and can be easily confused with it. L. crudelis has a thicker node along the anterior part, with a convex cross-section, in contrast with the thin node of L. iheringi in dorsal view, with vertical lateral sides, and more flattened top. The anterior margin in dorsal view is less than one-fourth the width of the posterior margin. The node of L. iheringi in lateral view has a continuously curved anterodorsal margin, and the eye in L. iheringi is weakly convex, whilst it is totally flat in L. crudelis. The scape surpasses the posterior cephalic margin by less than one-third its length in L. iheringi and the internal and masticatory mandibular margins meet through a rounded angle. The Paraná specimens have very parallel mandibles and a more pronounced mandibular angle, plus darker coloration.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

The biology of Leptogenys crudelis is poorly known.

The Leptogenys genus page has more details about the general biology of ants in this genus, some of which is summarized in what follows. New World species have relatively small ranges, generally occur in humid forests and prey on isopods. Colonies may occur in high densities on a local scale, with up to 5 or 6 species present. Nest size tends to be small with just 20 or 30 individuals in a mature colony. Nests of most species may be found in rotten wood on the ground, usually within cavities in logs or large branches, and also beneath bark. Wood-soil and rock-soil interfaces are another common nesting location, as well as rock crevices, and a few species may nest directly in the soil. Reproduction is most commonly via ergatoid females and, in many species, may include egg-laying workers.

Castes

Male unknown.

Nomenclature

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

  • crudelis. Ponera crudelis Smith, F. 1858b: 97 (w.) BRAZIL. Lattke, 2011: 152 (q.). Combination in Lobopelta: Mayr, 1886c: 358; in Leptogenys: Emery, 1911d: 105. Senior synonym of rubicunda: Borgmeier, 1932b: 485.
  • rubicunda. Leptogenys (Lobopelta) rubicunda Borgmeier, 1930: 28, pl. 4, figs. 13, 14, 17, 21, 25, 26 (w.q.) BRAZIL. Junior synonym of crudelis: Borgmeier, 1932b: 485.

The following notes on F. Smith type specimens have been provided by Barry Bolton (details):

Ponera crudelis

Two worker syntypes in The Natural History Museum. Labelled “Constancia, Jan. 1857. H. Clark,” and “57/43.” Acc. Reg.: “1857 no. 43 (May 16). Brazil. Presented by the Rev. Hamlet Clark. Collected at Constancia, Petropolis and other localities in the province of Rio. The localities are attached to each specimen.”

Two further workers are present in The Natural History Museum that are identical and probably originated in the type-series, but they have passed through the Farren White collection and have lost their original labels.

There is also one worker syntype in Oxford University Museum of Natural History (with a pupa mounted on the same card). Labelled “Constancia, Jan. 1857. H. Clark.”

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

Description

Worker

Lattke (2011) - Metrics (n = 5): HL 1.21-1.34; HW 0.76-0.81; ML 0.63-0.73; EL 0.18-0.25; SL 1.19-1.39; PW 0.68-0.71; WL 1.85-2.02; PH 0.68-0.73; PL 0.68-0.73; DPW 0.43-0.48 mm. CI 0.60-0.64; MI 0.83-0.97; OI 0.23-0.31; SI 1.56-1.72; LPI 0.93-1.00; DPI 0.59-0.68.

Head elongate, rectangular in full-face view, widest anterad than posterad, lateral margin broadly curved, curvature sharpest posterad; posterior cephalic margin straight with well-defined vertexal carina. Anterior clypeal process triangular, gradually tapering to blunt point; eye length almost one-fourth of lateral cephalic margin; eye flat, ocular mid-point closer to mid-length of cephalic lateral margin than to mandibular insertion. Mandibular dorsal surface smooth and shining, basal and external margins subparallel, masticatory margin edentate; basal angle blunt; PF: 4,3. Cephalic dorsum mostly smooth and shining; scape smooth and shining with abundant inclined pilosity; scape surpasses cephalic posterior margin by more than one-third its length; third antennal segment longer than either second or fourth segment, fourth antennal segment more than half as long as third segment; funicular segments subcylindrical, without sharp constriction between each.

Promesonotal dorsal margin forms more or less single convexity in lateral view, metanotal groove deep and broad, propodeal dorsal margin broadly convex, declivity sharply convex, propodeal lobes at spiracle height, bluntly triangular; mesosoma mostly smooth and shining; mesopleuron with carina along anterior margin and sparse low rugulae posteriorly; metapleural rugulose towards bulla; mesopleural suture impressed at level of metathoracic spiracle; mesometapleural suture well impressed, scrobiculate. Mesonotum wider than long in dorsal view, anterior margin convex, posterior margin straight to weakly concave. Propodeal spiracle elongate and oval, vertical; declivity with parallel transverse striae. Body smooth and shining with no appressed pubescence, with scattered subdecumbent to suberect fine golden hairs, scape with abundant decumbent pilosity.

Petiole roughly subquadrate in lateral view, with semi-vertical anterior and posterior margins, both tending to converge dorsad; dorsal margin convex, higher posterad than anterad, anteroventral process quadrate, with anterior and posterior angles. Posterior face of node smooth and shining, sides curving on to posterior face. Node in dorsal view triangular, slightly longer than wide; anterior margin convex, less than half as wide as posterior margin; lateral and posterior margins straight, joined by curves; node smooth and shining. Gaster with anterior margin almost vertical in lateral view, very broadly convex, curving strongly at a level 3/4 height of node, smooth and shining throughout; constriction between third and fourth abdominal segments well marked. Body dark brown; legs, mandible, and clypeus slightly lighter colored.

Queen

Lattke (2011) - Metrics: HL 1.47; HW 0.96; ML 0.78; EL 0.35; SL 1.47; PW 0.83; WL 2.07; PH 0.91; PL 0.71; DPW 0.68 mm. CI 0.66; MI 0.82; OI 0.37; SI 1.53; LPI 1.29; DPI 0.96. Queen with usual differences from workers; three well-developed ocelli present.

Type Material

Lattke (2011):

Syntype workers: Brazil, Constancia, i.1857 (H. Clark) (Oxford University Museum of Natural History, The Natural History Museum) [examined].

Leptogenys (Lobopelta) rubicunda. Syntype workers: Brazil, Rio de Janeiro, Petropolis, ix.1928 (A. Wiltuschnig) (Museu de Zoologia da Universidade de Sao Paulo) [examined].

The worker syntype in the Hope Museum is on a card mount, along with a cocoon. The scape is partially glued to the card, thus the distance it surpasses the posterior cephalic border can not be totally gauged. The data label states: Constancia, Jan 1857, H. Clark. Type Hym 933. Ponera crudelis. The two syntype workers in BMNH bear the same locality and collector data as the OXUM worker but carry a data disk that is absent from the Oxford specimen, “57/43”. The BMNH Accessions Register for 1857, no. 43 states, “May 16. Brazil. Presented by the Rev. Hamlet Clark. Collected at Constancia, Petropolis and other localities in the province of Rio. The localities are attached to each specimen”. A worker in the MZSP is glued to a similar card as the type, and is also similar in the way the legs and antennae are spread. It bears a label stating Brazil, Col Smith, plus an additional label stating “compared with Leptogenys crudelis type, H. Donisthorpe det. 25.vii.1932”. It also has another determination label by Borgmeier. Examination of the L. rubicunda types revealed no significant differences from L. crudelis, as Borgmeier (1932) realised when he studied the L. crudelis type, confirming what he suspected upon describing L. rubicunda.

References