Strumigenys rudinodis

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Strumigenys rudinodis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. rudinodis
Binomial name
Strumigenys rudinodis
Stärcke, 1941

Strumigenys rudinodis casent0280703 p 1 high.jpg

Strumigenys rudinodis casent0280703 d 1 high.jpg

Specimen Labels

The type material was found in peat and a non-type specimen is noted as being found in a forest.

Identification

Bolton (2000) - A member of the Strumigenys leptothrix-group. S. rudinodis shares its dentition (see under introduction to group) and characteristic propodeal organisation with Strumigenys megaera, Strumigenys scolopax, Strumigenys scylla and Strumigenys medusa within the leptothrix-group. The propodeum in all these species is armed with a pair of narrow acute spines that are subtended by sharp but narrow carinae. These carinae run down the declivity on each side to an acutely triangular propodeal lobe that is directed upward and backward. The declivity does not have broad lamellae subtending the spines.

Of the five species, scylla and medusa have numerous long fine hairs that project out from the dorsal (outer) surfaces of the middle and hind tibiae. These hairs are conspicuously longer than the maximum width of the segment on which they arise, and similar hairs also occur elsewhere on the legs. These two species also have abundant long, fine, apically acute, curved standing hairs on the promesonotal dorsum. In rudinodis, scolopax and megaera the middle and hind tibiae bear short, apically-directed decumbent hairs and the dorsal alitrunk has relatively sparse hairs that are short and tend to be more or less straight and blunted apically.

With the head in profile megaera and scolopax have only a single transverse row of standing short hairs, located close to the occipital margin, whilst rudinodis has a dense series of standing hairs between the highest point of the vertex and the occipital margin, distinctly more than a single transverse row. In megaera the dorsal outline of its clypeus in profile rises almost vertically from the mandibles before curving posteriorly, giving the anterior part of the clypeus a broadly convex and somewhat bulging appearance. The dorsal outline of the clypeus in rudinodis and scolopax, in the same view, is evenly shallowly convex from anterior to posterior margin, with the highest point of the convexity at the midlength.

Keys including this Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -6.587° to -6.699°.

 
North
Temperate 		North
Subtropical 		Tropical South
Subtropical 		South
Temperate

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (type locality), Malaysia.

Distribution based on AntMaps

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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.
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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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Biology

Castes

Nomenclature

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

  • rudinodis. Strumigenys (Cephaloxys) inezae var. rudinodis Stärcke, 1941: ii (w.) INDONESIA (Java). Combination in Weberistruma: Brown, 1953g: 26; in Pyramica: Bolton, 1999: 1673. Raised to species: Brown, 1953g: 26; in Strumigenys: Baroni Urbani & De Andrade, 2007: 127. See also: Bolton, 2000: 438.

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

Description

Worker

Brown (1953) - TL 3.04-3.12, HL 0.72-0.74, WL 0.81-0.84, CI 68-70, MI 17-18). (Measurements and description based on four para types sent by Dr. Starcke.)

This species is large, slender and quite long legged for a smithistrumiform ant. Head form much as in other Weberistruma species. Antennal scape as normally exposed about 0.4 1 mm. long in an "average" specimen, slightly thickened in apical half, faintly sigmoidal. Funiculus in same specimen about 0.63 mm. long; apical segment slightly shorter than I-IV taken together; IV slightly longer than I; I subequal in length to II + III; II and III both slightly longer than broad (cf. original description).

Promesonotum markedly depressed, only weakly convex, but not greatly broadened and with only the finest of dorsolateral carinulae forming distinct but feeble margins on each side posteriorly at the level of the mesonotum. Pronotum narrowly rounded anteriorly, without humeral angles; no margin separating pronotal dorsum from dorsum of "neck." Posterior mesonotum forming a laterally marginate concavity ending at the very feeble metanotal groove, the later distinct at all only because the propodeal dorsum rises very slightly but rather abruptly from it posteriorly. Propodeal dorsum flat, its sides submarginate, diverging posteriorly and continued as the long, sharp, somewhat depressed propodeal teeth. These teeth are as long or slightly longer than the distance between the centers of their bases and are slightly elevated and diverging posteriorly. Infradental lamellae reduced to low, even carinae, each of which has developed at its ventral extremity a prominent, acute tooth, inclined dorsad and about half as long as the dorsal tooth. Lateral aperture of transsternal groove (above and behind anterior coxa ) rather conspicuous, the fine hairs evident; suture running dorsad from it rather fine.

Petiolar node extremely poorly defined, its dorsal surface continuous with and a little longer than its peduncular dorsum. Node seen from above subovate, narrowed anteriorly, not more than 3/4 as broad behind as long (cf. original description). Posterior spongiform collar only weakly developed, narrow; midventral strip well developed, areolate, the anterior part forming a deep rounded hanging lobe. Postpetiole depressed-subglobose, but distinctly broader than long; shorter, and about 1/3 broader than the petiolar node; a feeble longitudinal costula traversing the length of the dorsal face on each side, other costulae feebly suggested. Spongiform appendages only moderately well developed except ventrally, where much-areolated hanging lobes are fairly heavy. Gaster long-oval, pointed at apex, feebly depressed dorsally, very slightly wider than the head: transverse anterodorsal border and anteroventral pad of spongiform tissue moderately developed; basal costulae subvestigial, very short and few, no more than 10 in my specimens; gastric surface smooth and shining.

Entire head, including clypeus, entire alitrunk, legs and both nodes densely punctulategranulose and opaque.

Ground pilosity on Ihe anterior 3/4 of cephalic dorsum composed of short, fine, inconspicuous appressed hairs, directed anteromedially for the most part. Clypeus and mandibles with similar hairs, narrowly spatulale, more densely arranged and a little more conspicucus, but not longer; closely appressed; Those in the center of the clypeus anteriorly most densely packed, oblique, and forming a sort of blunt anteromedian peak to the anterior free clypeal border; however, this illusion disappears under benzine, when the actual clypeal border at this limited median point appears truncate or feebly subemarginate. Hairs on scapes short, fine, subappressed, directed apicad. Hairs of underside of head, tibiae and tarsi also fine, reclinate, directed distally.

Erect pilosity consisting of long whitish hairs, stiff but weak, not apically enlarged, but more or less distinctly truncate apically, averaging 0.12-0.15 mm. in length, a bit shorter on the head than on alitrunk, distributed as follows: 25-30 on the posterior third of the cephalic dorsum, weakly curved anteriorly; 20 or so on the dorsum of the alitrunk, mostly restricted to origins near or on the lateral margins; a few on each of the nodes; a sparse growth of perhaps 30 on the gastric dorsum, tending toward arrangement in transverse rows of four. Venter of gaster and surfaces of femora with similar, but slightly shorter hairs, both perpendicularly and obliquely erect.

Color in my specimens bright ferruginous yellow, but these are evidently teneral, for Starcke notes in his description that some of his workers are more deeply colored: "De volkomen uitgekleurde werksters zijn roestbruin, met de middelelste 5/6 van het gaster donkerbruin, doch de meeste individuen zijn niet uitgekleurd, van stroogeel tot bruingeel."

Bolton (2000) - Type-material of this species was redescribed in some detail by Brown (1953a: 26). A more recently collected series from West Malaysia is smaller: HL 0.64-0.68, HW 0.43-0.45, CI 65-67, ML 0.09-0.10, MI 15-17, SL 0.32-0.34, SI 71-77 (10 measured). These specimens otherwise match the type-series.

Type Material

Syntype workers, INDONESIA: Java, Bogor ( = Buitenzorg), G. Poentjak, 1400 m., iii.1936 (E. Jacobson) (Leiden Nationaal Natuurhistorische Museum, National Museum of Natural History, Museum of Comparative Zoology) [examined].

References

References based on Global Ant Biodiversity Informatics

  • Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
  • Brown W. L., Jr. 1953. Revisionary studies in the ant tribe Dacetini. Am. Midl. Nat. 50: 1-137.
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