Strumigenys inopina

Strumigenys inopina
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. inopina
Binomial name
Strumigenys inopina (Deyrup & Cover, 1998) Specimen labels

This species is only known from the queen. It is suspected to be a social parasite (Deyrup & Cover, 1998; Booher, 2021).

At a Glance

• Workerless Inquiline

Identification

Deyrup and Cover (1998) - Clypeus, antennal scapes, dorsum of mesosoma, gaster with coarse hairs rising from conspicuous punctures; no broadened or flattened hairs on head, body, or appendages; spongiform appendages absent; antennal scrobes absent.

Bolton (2000) - A member of the Strumigenys rostrata-group. This species, known only from the queen, is tentatively placed in the rostrata-group because of its dentition and the fact that there appear to be a number of hairs on the leading edge of the scape that are curved toward the scape base. It is separable from queens of all other U.S.A. species by its complete lack of antennal scrobes and lack of any trace of spongiform tissue on both petiole and postpetiole. In addition the alitrunk in profile is compact, short and high, basigastral costulae are absent and flagellate hairs are absent.

Keys including this Species

• Key to Nearctic Strumigenys (as Pyramica)
• Key to US Strumigenys species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 32.60194444° to 29.21°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).

Distribution based on AntMaps

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.

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.

Biology

Deyrup and Cover (1998) - These specimens are the result of a survey, involving thousands of Berlese funnel samples, of the ants of Florida. Since the collecting phase of this project is almost complete, there is little chance that more specimens will be found soon. All three specimens were extracted by Berlese funnel from thick pine litter. The holotype was at the base of a Pinus elliottii Engelmann in wet, open flatwoods with Myrica cerifera L. and Quercus nigra L. along a trail by the Rodman Dam parking lot. The same sample of about two liters of unsifted litter included a large colony of Strumigenys clypeata with a queen, a colony of Nylanderia faisonensis with alates, numerous workers of Pheidole dentigula and a few workers of Hypoponera opacior. The Marion County paratype was from a xeric site with thick litter under dense Pinus clausa Chapman ex Engelmann and dense scrub oaks, Quercus myrtifolia Wildeman and Quercus geminata Small. The same two-liter unsifted sample included workers of Strumigenys talpa, Solenopsis carolinensis, and Nylanderia wojciki. The Alachua County paratype was from litter taken at the base of a pine, probably Pinus elliottii. The same sample included a large colony of Strumigenys dietrichi.

There is some circumstantial evidence that S. inopina might be a workerless parasite.

1. The species appears to be very rare; parasitic ants are frequently rare (Holldobler and Wilson 1990), known from only one or a few collections. There are, however, other dacetonines that are rarely collected in Florida, for example Strumigenys cloydi, Strumigenys abdita, and Strumigenys angulata.
2. Only females are known. This is consistent with the social parasite hypothesis, but not supportive, since several other rare Florida Strumigenys, for example S. angulata and Strumigenys pilinasis, are also represented by solitary dealate females more often than one might expect. We assume that this means that the colonies of these species are not only rare, but also in microhabitats that are difficult to sample, so the species is most widely dispersed in the form of queens prospecting for a nest site, rather than as foraging workers.
3. All three females were taken in relatively small samples that also included other species of Strumigenys. If S. inopina is parasitic, its hosts are most likely to be, according to “Emery's rule,” close relatives (Holldobler and Wilson 1990), i,e. other Strumigenys sp.
4. Species of Strumigenys, as well as other dacetonines, are characterized by modifications, often elaborate, of the mandibles, pilosity, cuticular sculpture, grooves and depressions of the head and body, and spongiform appendages.

Queens share most or all of the morphological elaborations of conspecific workers. The function of these character states is not understood in any specific way, but it seems likely that they are associated with defense and prey capture, The absence of all typical dacetonine elaborations in S. inopina suggests that this species makes its living in some novel way. One of the features of many parasitic ants is the loss of cuticular sculpture (Holldobler and Wilson 1990). A sparse pilosity of curved, tapering, suberect hairs is typical of the parasitic genera Strongylognathus, Protomognathus, and Harpagoxenus; in the cases of the latter two genera, this pilosity contrasts with the short, scale-like hairs of the hosts. Strumigenys margaritae approaches S. inopina in its lack of antennal scrobes, the position of the eyes far from the ventral margins of the head, the greatly reduced spongiform appendages, and the lack of grooves at the base of the first gastral tergite. This could be a convergence based on some degree of dependence On other species, especially for defense. In Trinidad one author (MD) and Lloyd Davis observed workers of S. margaritae mingled in a foraging column of Wasmannia auropunctata moving along a piece of plastic irrigation pipe on an open hillside each morning for three consecutive days. Returning to the site two years later, Lloyd Davis (personal communication) found this mixed foraging column still occurring. We do not suggest that S. margaritae is parasitic, only that it may have an unusual relationship with other ants.

It is reasonable these days to consider the conservation status of newly described species if there is reason to believe that the species are rare, localized, or have narrow habitat requirements. Strumigenys inopina is known from the northern border of Ocala National Forest (the holotype locality) and from another site not far from the western side of the forest. Since the Ocala National Forest is a huge tract (380,000 acres), much of which is maintained in relatively natural habitats, the chances are good that there are protected populations of S. inopina that should be able to persist within the forest.

Southeastern Strumigenys are centered around the southern Appalachians, with some species having ranges extending up to southern New England, or down into Florida, or west to eastern Texas. Because of the consistency of this pattern, we suspect that this species will be found to have ranges considerably north of the localities listed above.

Nomenclature

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

• inopina. Smithistruma inopina Deyrup & Cover, 1998: 215, fig. 1 (q.) U.S.A. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 121. See also: Bolton, 2000: 129.

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

Description

Queen

Holotype. Total length (calculated as in Brown 1953): 2.40; head length: .62; head width: .36; length of mesosoma: .56.

Mandible in frontal view narrowly triangular, basal tooth an isoceles triangle, teeth of apical series small, longest about half as long as length of basal tooth, first and third longest, subequal, second and fifth subequal, about half length of first and third. fourth and sixth to eighth small, subequal: clypeus shining, with a small median submarginal tubercle and sparse conspicuous tapering hairs arising from punctures; remainder of head finely punctate, with moderately dense tapering hairs; long, flagelliform hairs absent on head; antennal scrobes absent; antennal scapes with sparse tapering hairs arising from punctures, hairs along inner edge proclinate on proximal third of scape, reclinate on distal two thirds of scape; head in frontal view wedge-shaped, as in Strumigenys clypeata.

Dealate, wing stumps present, flight structures well developed; pronotal angle rounded, sides of mesosoma not concave anteriorly; pronotum, mesonotum, metanotum, propodeal declivity smooth, shining, with sparse, curved, tapering hairs; sides of alitrunk smooth, shining; propodeal spines short. not subtended by a lamina; coxae smooth, shining, anterior surfaces with Sparse tapering hairs; femora and tibiae with sparse proclinate tapering hairs.

Petiole, postpetiole, and base of gaster Without spongiform appendages; gaster without grooves on first tergite; dorsum of petiole, postpetiole, and gaster smooth, shining, with sparse, tapering, curved hairs rising from punctures.

Color yellowish brown.

Type Material

Bolton (2000) - Holotype queen, U.S.A.: Florida, Putnam Co., Ocala National Forest, Rodman Resevoir, trail near parking lot, at base of pines, wet flatwoods habitat, 10.xii. 1 994 (M. Deyrup); paratype queen, Florida, Marion Co., 9 miles SSW of Ocala, in Ocala Waterway Development, sand pine scrub habitat, 16.x.1990 (M. Deyrup); paratype queen, Florida, Alachua Co. , Alachua Co. Fairgrounds, at base of pines, flatwoods habitat near parking lot, 23.ii.1986 (C. Johnson) (Museum of Comparative Zoology, Archbold Biological Station collection) [not seen].

Strumigenys inopina is described from three females, with no workers or males available. All three specimens were extracted by Berlese funnel from thick pine litter.

Etymology

Inopina (Latin), “unexpected,” referring to the novel suite of character states displayed by the species.

References

• Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria” 99:1-191.
• Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). Journal of Natural History. 33:1639-1689.
• Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.
• Booher, D.B. 2021. The ant genus Strumigenys Smith, 1860 (Hymenoptera: Formicidae) in western North America north of Mexico. Zootaxa 5061, 201–248 (doi:10.11646/zootaxa.5061.2.1).
• Deyrup, M. and Cover, S. 1998. Two new species of Smithistruma Brown (Hymenoptera: Formicidae) from Florida. Proc. Entomol. Soc. Wash. 100: 214-221. (page 1998, queen described)

References based on Global Ant Biodiversity Informatics

• Deyrup M., and S. Cover. 1998. Two new species of Smithistruma Brown (Hymenoptera: Formicidae) from Florida. Proceedings of the Entomological Society of Washington 100: 214-221.
• Deyrup, M. 2003. An updated list of Florida ants (Hymenoptera: Formicidae). Florida Entomologist 86(1):43-48.
• Deyrup, M. and S. Cover. 2009. Dacetine Ants in Southeastern North America (Hymenoptera: Formicidae). Southeastern Naturalist 8(2):191-212
• MacGown J. A., and J. G. Hill. 2010. A new species of Pyramica from Mississippi, U.S.A. Florida Entomologist 93: 571-576.