Odontomachus floresensis

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Odontomachus floresensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Odontomachus
Species: O. floresensis
Binomial name
Odontomachus floresensis
Brown, 1976

Odontomachus floresensis casent0270619 p 1 high.jpg

Odontomachus floresensis casent0270619 d 1 high.jpg

Specimen Labels

Both type localities are in the lowlands along the main road along the north shore of Flores Island, Indonesia. At Nangagete, the ants were taken foraging near midday in scrubby second growth forest, and nesting under a log in the shade. At Wodeng, the ants were foraging by day on the floor of a shady remnant of tropical evergreen forest growing on a hillside seepage area. (Brown 1978)

Identification

Brown (1976) - In life, the red head and yellow legs are bright and contrast with the blackish color of the rest of the body; the pattern is probably aposematic. The color pattern is the best means of distinguishing Odontomachus animosus, a similar form of the infandus group. Odontomachus sumbensis is similar, but has the vertex and pronotal disc smooth, and the petiolar node and spine lower. All of these forms could possibly be geographical representatives of animosus or another species in the infandus group, but I am following the hypothesis that the insular forms, at least, are member species of a superspecies.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Nomenclature

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

  • floresensis. Odontomachus floresensis Brown, 1976a: 146 (w.) INDONESIA (Flores I.)

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

Description

Worker

Holotype: TL 12.7, HL 3.00, HW (across vertex) 1 .90, HW (across ocular prominences) 2.25, ML 1.56, scape L 2.84, eye L 0.50, WL 3.96 mm; CI 63, MI 52, SI 149.

Paratypes, 12 workers from type locality (Nangagete) and 3 from Wodeng, Flores; only 3 were measured in detail, including the largest and smallest specimens, and the metrics are given combined with those of the holotype in Table II.

A relatively broad-headed member of the infandus group with cephalic dorsum and pronotum distinctly striate completely or nearly completely ; head and mandibles deep red; trunk, petiole and gaster piceous to black (pronotum and gastric apex more or less suffused with reddish); legs and antennal funiculi yellow; antennal scapes castaneous. Petiolar node with a very short, inconspicuous peduncle; rising from this, the anterior face of the node is gently convex in outline for a variable distance, and above that, weakly concave to the root of the spine, and sometimes all the way to the tip of the spine. The spine itself is back-tilted, long and very slender, taking up about 1 /3 the height of the node as measured from the lateral suture of the petiole, and is straight or gently curved caudad. Posterior face of node steeply sloping, side-view outline sinuate, concave at root of spine, convex at upper part of node, and feebly concave beneath the convexity. The convex upper face is obscurely sulcate on the midline. Similarly shaped nodes are seen in occasional specimens of O. papuanus, but in papuanus and infandus, the concavity of the upper anterior face of the node is usually much more profound. In O. floresensis, the spine is more abruptly narrowed at its base than in related forms, except sumbensis; in sumbensis, the node is thicker anteroposteriorly, and the spine is shorter than in floresensis. In view of the great variability of nodal shape in the infandus group, the value of these characters is debatable.

The striation of the head in O. floresensis is moderately coarse (about 5 striae in a square of 0.1 mm in the middle of the left side dorsal surface of the vertex) and extends back to a narrow smooth strip just before the nuchal carina, and down the sides of the head to a level below the eyes; also the cheeks are striate between eye and mandibular insertion. Some specimens, including the holotype, show a tendency to have the striation effaced in a narrow strip along each side of the median furrow on the upper vertex, and the surface here may be nearly or quite smooth, with a few scattered punctures.

Pronotal striation fine, transverse, often forming a flattened transverse whorl on the front part of the disc. Mesonotum low, its anterior edge not so sharply projecting above pronotal posterior margin as in O. sumbensis, and the mesonotal surface more convex from front to rear. Metanotum usually not markedly impressed, often convex, though separated from the propodeum by a distinct suture. Propodeal dorsum distinctly but very shallowly concave near midlength. Mesonotum and metanotum finely, propodeum more coarsely, transversely striate. Coxae, node and gaster smooth and shining. Legs shining, but minutely and densely punctulate and finely pubescent. Mandibles minutely roughened and punctate above, subopaque. Antennal scapes minutely and densely punctulate, pubescent, only weakly shining. Mesopleura finely vertically striate anteriorly and near upper margin; smooth with blue opalescent reflections and scattered punctures over posteromedian part. Pubescence on head, mandibles and gaster appressed, very sparse and fine, visible only in certain lights; better developed (but still not conspicuous) and decumbent on underside of head, on trunk and front and sides of petiolar node. Erect hairs on body very sparse: the usual middorsal cranial pair; 2-3 pairs of short hairs on the underside of the head near the mouth, plus the usual coarse sense hairs on the mandibles; usually 1-6 long, curved erect hairs on pronotal disc; zero to a few fine hairs on anterior coxal surfaces; zero to 3-4 fine erect hairs on posterior of first gastric tergum, and scattered, long fine hairs on underside and apical segments of gaster and on undersides of coxae, bases of femora, etc.

The first gastric tergum is strongly convex in both directions, not at all flattened, and the second tergum has the usual shallow transverse impression. Labial palpi 4-merous, but rather short and stout. Antennal scapes surpassing posterior border of head by more than the length of the pedicel (funicular segment I); proportions of funicular segments as described for Odontomachus sumbensis.

Type Material

Holotype (Museum of Comparative Zoology) and 12 paratypes (MCZ, The Natural History Museum-London, and elsewhere) from Nangagete, about 60 km east of Maumere on the north coast of Flores Island, Indonesia, July 1972 (W. L. Brown), and 3 workers from Wodeng, about 31 km east of Maumere, also near the north coast of Flores, on another day in July 1972 (Brown).

References