Dorymyrmex grandulus

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Dorymyrmex grandulus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Dorymyrmex
Species: D. grandulus
Binomial name
Dorymyrmex grandulus
(Forel, 1922)

Dorymyrmex grandulus casent0103878 profile 1.jpg

Dorymyrmex grandulus casent0103878 dorsal 1.jpg

Specimen labels

A small Dorymyrmex species that occurs in woodland and adjacent open areas.

Identification

Trager (1988) - A small dusky yellowish brown to dark brown species. Forel (1922) described specimens of this this species as a variety of Nylanderia parvula.

Superficially, D. grandulus resembles a depauperate Dorymyrmex medeis (=Dorymyrmex smithi), but has proportionately smaller and narrower head with occipital border weakly convex and propodeal cone sharp with narrow base.

Keys including this Species

Distribution

Trager (1988) - Known from Alabama, northern Florida, and the eastern seaboard states north at least to the New Jersey Pine Barrens. The true range of this ant may be much more extensive. I have seen similar Dorymyrmex specimens collected in Michigan and New York, but have not had the opportunity to study them carefully. Buren (personal communication) felt that Michigan specimens he saw were "probably different", but sensing his caution, I prefer to leave open the question of their conspecificity with D. grandulus.

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Trager (1988) - Until I serendipitously discovered the types of D. grandulus, Buren had intended to describe this species as new with a name referring to its frequent occurrence in woodland openings. Specimens from Georgia are labeled "pine-oak on clay"; however most series have been collected in sandy soils. One series was from sand dunes, and the level of development of the vegetation was not indicated, and I made one collection of this species at the edge of a temporary pond in full sun, many meters from the nearest tree. The types were collected by Forel without a habitat notation, but he also collected Nylanderia faisonensis at the type locality; the latter is a species of mesic woodlands.

Castes

Nomenclature

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

  • grandulus. Prenolepis (Nylanderia) parvula var. grandula Forel, 1922: 98 (w.) U.S.A. Trager, 1988: 24 (q.). Combination in Paratrechina (Nylanderia): Emery, 1925b: 222; Creighton, 1950a: 409; in Conomyrma: Trager, 1984b: 64; in Dorymyrmex: Shattuck, 1992c: 85. Junior synonym of parvula: Creighton, 1950a: 409. Revived from synonymy and raised to species: Trager, 1984: 64. See also: Johnson, C. 1989b: 192 (in key).

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

Trager (1988):

Description

Worker

HL 0.63-0.90 (0.82), HW 0.53-0.75 (0.67), SL 0.63-0.91 (0.85), EL 0.16-0.23 (0.22), FL 0.55-0.80 (n.a.), WL 0.83-1.18 (1.13), HTL 1.46-2.08 (1.95), CI 80.0-87.3 (82.0), SI 110.3-130.0 (126.9), OI 22.7-28.6 (26.8), FI 80.8-93.6 (n.a.), TI 124.0-140.0 (138.0). N =21. Lectotype selected and measured by Roy R. Snelling, LACM; deposited in Forel collection Museum d'Histoire Naturelle, Geneva, Switzerland.)

General form and characters as in figures, and in key.

Head shape variable, ranging from that shown in figures to more nearly straight-sided and convergent toward occipital border (this variation may be found in any large nest series of D. grandulus and has no relationship to overall body size); head usually widest across eyes; promesonotal profile often as in figure, but often contiguous faces of pro- and mesonota higher and more arched; rarely mesonotal profile strongly arched, obliterating usual angle (one will not be able to take such specimens through key but other specimens from same series will have the normal conformation); propodeal profile reminiscent of that of Dorymyrmex medeis (=Dorymyrmex smithi), but basal face of propodeum 2 or more times as long as base of propodeal cone (only I to 2 times as long in C. medeis) and cone is generally sharper-tipped than in D. medeis; propodeal cone often appears inclined forward.

Mandibular striation similar to that of Dorymyrmex bureni in extent, but consisting of 3 or 4 coarser striae with 1-2 finer striae adjacent to each of these; tessellation coarser than in D. bureni, thus cuticle shinier, but this obscured by longer pubescence.

Color of D. grandulus varying from piceous to yellowish brown; often clypeus and thorax a little yellower, and occasionally (teneral?) both head and thorax yellowish; mandibles yellow to brown; legs about the color of gaster; D. grandulus usually has a "mousy" color due to the obscuring of the cuticle by longer than average (for the genus), grayish pubescence.

Queen

HL 1.20-1.25, HW 1.23-1.28, SL 1.09-1.15, EL 0.40-0.43, TW 1.18-1.30, WL 2.38-2.45, HTL 3.58-3.70, CI 95.4-103.7, SI 84.4-93.2, OI 32.0-34.4, TWI 93.8-107.8, TI 194.4-204.2. N =6

Head a little broader than long: sides weakly convex or faintly angular, converging slightly toward occipital border, more strongly so toward clypeus; outer margin of eyes close to or reaching sides of head; occipital border about as broad as clypeus; thorax usually notably broader than head.

Sculpture coarser and pubescence longer than in worker, thus queen notably duller; color uniform dark brown or with head and thorax a little lighter and more reddish.

Type Material

Lectotype and 1 paratype: North Carolina, Duplin Co.: Faison, A. Forel, 1921.

Etymology

The adjective grandulus is the diminutive form of Latin grandis (large). Dr. Forel (1922) noted that this species was somewhat larger than the species with which he mistakenly believed D. grandulus to be conspecific, Nylanderia parvula.

References

  • Creighton, W. S. 1950a. The ants of North America. Bull. Mus. Comp. Zool. 104: 1-585 (page 409, Combination in Paratrechina (Nylanderia))
  • Forel, A. 1922b. Glanures myrmécologiques en 1922. Rev. Suisse Zool. 30: 87-102 (page 98, worker described)
  • Johnson, C. 1989b. Taxonomy and diagnosis of Conomyrma insana (Buckley) and C. flava (McCook) (Hymenoptera: Formicidae). Insecta Mundi 3: 179-194 (page 192, see also (in key))
  • Shattuck, S. O. 1992c. Generic revision of the ant subfamily Dolichoderinae (Hymenoptera: Formicidae). Sociobiology 21: 1-181 (page 85, Combination in Dorymyrmex)
  • Trager, J. C. 1984b. A revision of the genus Paratrechina (Hymenoptera: Formicidae) of the continental United States. Sociobiology 9: 49-162 (page 64, Combination in Conomyrma, Revived from synonymy and raised to species)
  • Trager, J. C. 1988a. A revision of Conomyrma (Hymenoptera: Formicidae) from the southeastern United States, especially Florida, with keys to the species. Florida Entomologist. 71:11-29. PDF (page 24, queen described)