Rogeria stigmatica

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Rogeria stigmatica
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Rogeria
Species: R. stigmatica
Binomial name
Rogeria stigmatica
Emery, 1897

Rogeria-stigmata-MCZ001L.jpg

Rogeria-stigmata-MCZ001D.jpg

Specimen Label

Synonyms

Most collections come from berlesate or sifting of leaf mould, rotten wood, soil, moss, or bases of fern epiphytes in rain forest. The one nest series with ecological data (Sorong, Irian Jaya) is from rotten wood. Mann (1921:451) found colonies beneath stones and logs. Twelve specimens, were collected on imported coconuts in Honolulu. If nesting occurs in coconuts, colonization of Polynesia and Melanesia from South America may have occurred by rafting on the South Equatorial Current. Mann (1921:451) observed workers producing long, worm-like stands from the anal area when the nest was disturbed. (Kugler 1994)

Identification

Kugler (1994) - stigmatica species group. WL 0.72-0.92mm. Mandibles usually subtriangular. EL usually ≥ 0.10mm. Propodeal spiracle ≤ half its diameter from edge of infradental lamella. Propodeal spines short (PSI 0.07-0.13), strongly inclined dorsad. Metapleural lobes much reduced. Inferior petiolar process absent. Abundant decumbent hair on head, mesosoma, waist and gaster; erect hairs rather sparse, not flexuous.

See Rogeria megastigmatica, Rogeria ciliosa and Rogeria gibba for similar South America species and Rogeria exsulans for a not so related species from the Pacific.

Keys including this Species

Distribution

Rogeria stigmatica is known only from the Central and West Pacific, from as far east as Tahiti to the western tip of the Island of New Guinea and from about 22°S to 7°N (Kugler 1994).

Distribution based on Regional Taxon Lists

Australasian Region: New Caledonia.
Indo-Australian Region: American Samoa, Fiji, French Polynesia, Indonesia, Micronesia (Federated States of), New Guinea (type locality), Niue, Samoa, Solomon Islands, Tokelau, Tonga, Vanuatu, Wallis and Futuna Islands.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Rogeria stigmatica for further details

Biology

The following is modified from Kugler (1994): Little is known about these cryptic ants. Collection records typically range from sea level to 1000m, but five species extend higher and two (Rogeria unguispina and Rogeria merenbergiana) can be found at 2000m. Rogeria are generally collected in moist forests (primary or secondary forests, coffee or cacao plantations), but at higher elevations can be found in pastures (Rogeria leptonana, Rogeria merenbergiana). Several species (Rogeria creightoni, Rogeria cuneola, Rogeria foreli) have been found in moist and dry climates. Rogeria foreli is the most unusual, with some members dwelling at over 1800m in the temperate mountains of southern Arizona.

Most species have only been collected as strays or by Berlese or Winkler sampling, from leaf litter and rotten wood, but occasionally among epiphytes and moss (Rogeria belti, creightoni, Rogeria exsulans). Nests of several species (belti, Rogeria blanda, merenbergiana) have been found under the loose bark of rotten logs. Nests of blanda and Rogeria tonduzi have been taken from the trunks of cacao trees. A nest of Rogeria leptonana was found at 1750m under a rock in a pasture.

Nests are rarely found. Males are known for only four species (belti, blanda, leptonana and Rogeria stigmatica) and queens associated through nest series for only nine species.

Castes

Worker

Nomenclature

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

  • stigmatica. Rogeria stigmatica Emery, 1897c: 589 (w.) NEW GUINEA. Mann, 1919: 342 (q.m.). Senior synonym of manni, sublevinodis: Kugler, C. 1994: 33.
  • sublevinodis. Rogeria stigmatica subsp. sublevinodis Emery, 1914f: 415 (w.) NEW CALEDONIA (Loyalty Is). Wheeler, G.C. & Wheeler, J. 1955b: 28 (l.). Raised to species: Wilson & Taylor, 1967: 76. Junior synonym of stigmatica: Kugler, C. 1994: 33.
  • manni. Rogeria manni Santschi, 1922b: 353 (footnote) (w.) SOLOMON IS. Combination in Lordomyrma: Brown, 1953h: 4. Junior synonym of stigmatica: Kugler, C. 1994: 33.

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

Kugler (1994) - According to Emery (1914) and Wilson and Taylor (1967), Rogeria sublevinodis differs from Rogeria stigmatica in having larger size, coarser sculpture on head and mesosoma, and smooth nodes with coarser punctures on other parts of the waist. When two of Emery's stigmatica syntypes and two of his sublevinodis syntypes in the Musee d'Histoire Naturelle Genève were compared side by side, the TL and WL of the Rogeria stigmatica syntypes fell within the range of the Rogeria sublevinodis syntypes. The sculptural characteristics were not distinct either, except on the dorsal face of the propodeum, which is transversely rugulose and very weakly punctate and shiny in stigmatica syntypes, but densely punctate and lacking rugulae in the sublevinodis syntypes. However, intergrades with rugulae and various degrees of punctation occur in the Solomon Islands, Irian Jaya, and Pohnpei.

Santschi (1922) claimed that Rogeria manni differed from stigmatica in a variety of ways. After examining manni types, I could confirm only one clear way they differ from the types of stigmatica and sublevinodis: the presence of rugose sculpture instead of areolate sculpture on the promesonotum. However, in non-type material, I found all intermediate states, sometimes within the same locality. Other supposedly different characters also intergrade or are due to the manni types being at the small end of the size distribution.

I have too few collections from Papua New Guinea to know if those specimens with unusually small eyes and few erect hairs on gaster T1 might be a distinct species.

Description

Worker

Kugler (1994) - TL 3.0-3.7, HL 0.66-0.83, HW 0.58-0.71, SL 0.46-0.61, EL 0.05-0.15 (7-34 facets), PW 0.44-0.52, WL 0.72-0.92, SpL 0.05-0.10, PetL 0.32-0.42, PpetL 0.19-.23mm, CI 0.84-0.92, OI 0.08- 0.22, SI 0.79-0.87, PSI 0.07-0.13. N=28

Kugler 1994 fig 7-14

Mandibles subtriangular (usually) to triangular; with 5 subequal teeth or 3 apical teeth followed by 3-4 (rarely 5) smaller teeth or denticles. Palpal formula 3,3. Little or no clypeal apron; median clypeal margin truncate, weakly convex, or weakly angular. Body of clypeus not projecting over clypeal margin. Eyes oval, large (EL 0.10-0.15mm and 17- 34 facets), except in some of the Papua New Guinea workers (EL 0.05-0.07mm; 7-9 indistinct facets). Nuchal groove distinct from behind, but not clear in side view. Promesonotum with evenly convex profile. Metanotal suture narrow, emphasized by a sharp ridge at anterior edge of propodeum. Node large, wider than long, more or less symmetrical in side view (Fig. 8). Postpetiolar node in side view rounded front to back; usually widest in anterior half, much as in Fig. 66, but sometimes widest midlength. Postpetiolar sternum short. Sting apparatus like that of ciliosa (Fig. 3), except for: 1) spiniform medial and and lateral projections from anterodorsal corner of quadrate plates, 2) smaller valve chamber, and 3) lack of anterolateral processes on sting base (Fig. 9). Gonostylus sometimes with no clear sensillar gap; sometimes lacking a companion seta. The "Rogeria (stigmatica group) spp. 1 and 2" in Kugler (1978b) are both stigmatica. The sting shown here is more accurate than the previous one, which was not in full lateral orientation when drawn.

Middorsum of head longitudinally rugose; rest of head, including venter, coarsely areolate. Dorsum of promesonotum coarsely areolate to rugose (intermediate specimens predominantly areolate, but with elongate cells or short rugae medially; rarely, rugae also occur on shoulders). Anterior and sides of mesosoma areolate, finely so on neck and ventrad on meso- and metapleura. Spaces in sculpture smooth except for piligerous punctures. Dorsal face of propodeum areolate along very anterior margin, followed by either transversely rugulose or densely punctate sculpture, or both in varying degrees of density and definition. Petiolar peduncle finely colliculate or smooth. Anterior and apex of node smooth or areolate; posterior face and sides areolate, sometimes with a few rugae. Postpetiole transversely rugose-areolate behind, becoming more effaced anteriorly, often leaving anterior face smooth and shining.

Decumbent to subdecumbent pilosity covers most of body. Sparser erect to suberect hair also on dorsa of scapes, head, mesosoma, nodes, and gaster. Erect hair moderately abundant on gaster T1 of most specimens (Fig. 8), but sparse on specimens from Papua New Guinea. Body of clypeus with strong median seta.

Color of mandibles, frontoclypeal region, antennae, and legs light brownish-yellow to brown. Rest of body light brown to blackish-brown.

Queen

Kugler (1994) - TL 3.6-4.5, HL 0.73-0.85, HW 0.66-0.75, SL 0.53-0.62, EL 0. 19-0.24, PW 0.60-0.71, WL 1.00-1 .17, SpL 0.10, PetL 0.41-0.48, PpetL 0.21-0.26mm, CI 0.87-0.90, SI 0.80-0.84, PSI 0.09-0.10. N=6

As in worker except for the usual caste differences. Mesosoma habitus as in Fig. 10. Queen from McAdam Park, Papua New Guinea with median bulge on pronotum. Pronotum areolate on sides; finer and transversely rugose-areolate mesad. Mesoscutum longitudinally rugose; mesoscutellum areolate-rugose. Metanotum smooth. Mesosoma sides confused areolate, except for smooth area on mesokatepisterna and costulate metapleural gland bullae. Wing venation as in lirata (Fig. 30), except for Rs vein as in belti (Fig. 37).

Male

Kugler (1994) - TL 2.6-3.1, HL 0.45-0.54, HW 0.56-0.66 SL 0.27-0.35, EL 0.20-0.26, PW 0.50-0.62, WL 0.84-1.04, PetL 0.22-0.30, PpetL 0.14-0.19mm, CI 1 .22-1.27, SI 0.48-0.53. N=3

Mandibles with a large apical tooth and 4 others decreasing in size basad. Posterior lobe of clypeus projects more broadly between antennae than in worker; anterior clypeal margin weakly convex. Frontal lobes absent. No distinctly impressed frontal area. Funicular segment 6 curved and longer than 4 and 7; more extremely curved and elongate on one side of the head than the other. Posterior outline of head medially concave; sharp crests run from ocelli to posteroventral corners of head, which project slightly and fit around prothoracic sternum when head is retracted. Mesosoma and waist as shown in Fig. 11. Genitalia as shown in Fig. 12. Head integument vaguely roughened. Mesosoma and waist smooth, except along furrows and on sides of propodeum, metepimera, and petiolar peduncle. Gaster smooth and shining. Pilosity all erect to suberect, except around eyes. Propodeum nude. Color variation as in worker.

Type Material

Kugler (1994) :

Syntype workers, NEW GUINEA: Friedrich-Wilhelmshafen [=Madang] (Biró) Musee d'Histoire Naturelle Genève [Both syntypes examined].

Rogeria stigmatica subsp. sublevinodis Emery 1914:415. Syntype workers, LOYALTY ISLANDS: Maré, Raoua MHNG [Both syntypes examined].

Rogeria manni Santschi 1922:353. Syntypeworkers, SOLOMON ISLANDS: Fulakora, Ysabel Is. (Mann) Museum of Comparative Zoology, Naturhistorisches Museum Basel [12 syntypes examined].

References

  • Kugler, C. 1994. A revision of the ant genus Rogeria with description of the sting apparatus (Hymenoptera: Formicidae). J. Hym. Res. 3: 17-89 (page 33, Senior synonym of sublevinodis and manni)
  • Mann, W. M. 1919. The ants of the British Solomon Islands. Bull. Mus. Comp. Zool. 63: 273-391 (page 342, queen, male described)