Strumigenys ananeotes

Discovered in an urban, backyard garden in Salt Lake City by the myrmecologist Jack Longingo.

Identification
Longino and Booher (2019) - Strumigenys can be divided into 2 morphologically distinct groups: species with long linear mostly edentate mandibles, or species with short triangular mandibles with numerous teeth along most of their length. All species having ranges centrally located in the United States belong to the latter group, formerly known as the genus Smithistruma. These species are very similar in morphology and size, but have distinct pilosity and tooth patterns that separate species. Strumigenys ananeotes can be distinguished from all other North American species by tooth morphology alone. It is the only species in North America having the first 7 teeth alternating between similarly sized large and small pointed teeth. The basal-most tooth is small or missing, which gives a count of 8 or 7 for the teeth of alternating sizes. Strumigenys ananeotes is most similar to the western species Strumigenys chiricahua, eastern species Strumigenys hyalina, and Mexican species Strumigenys dispalata. In S. chiricahua, the first 3 teeth increase in size and do not completely overlap when the mandibles are closed, whereas in S. ananeotes, the large teeth overlap the opposing smaller teeth when the mandibles are closed. Strumigenys hyalina has similarly alternating large and small teeth, but the larger teeth decrease in size apically such that tooth 7 is only about half the length of tooth 1; in S. ananeotes, tooth 7 is only slightly smaller than tooth 1. In S. dispalata, teeth do not alternate in size, and tooth 2 is longer than tooth 3 and tooth 4. There are also differences in the shape of the spatulate setae on the anterior margin of the clypeus. In S. ananeotes the setae are apically truncated and have irregular margins; in S. hyalina they are also truncate but with evenly flat apical margins; in S. chiricahua, they are relatively narrower and evenly rounded along the anterior margins. Strumigenys ananeotes is also easily distinguished from other western species. In Strumigenys arizonica, the first and fourth mandibular teeth are subequal in length and shorter than the second, third, and fifth teeth. In Strumigenys californica, the first 6 teeth gradually and slightly decrease in size. Strumigenys reliquia has simple-to-subflagellate hairs on the clypeus. The only other species with similar mandibular teeth is the introduced species Strumigenys margaritae. It also has teeth that alternate in size, but the smaller teeth are blunt and not pointed as in S. ananeotes. However, in other characters, S. margaritae bears little resemblance to S. ananeotes.

Distribution
Known from an urban backyard in Salt Lake City, Utah. The city is in the Intermountain West, on the eastern edge of the Great Basin bioregion, in an area of strong continental climate. Winters are cold, and summers are hot and dry. Salt Lake City is hundreds of kilometers from the nearest record of Strumigenys, and there are certainly no previous records of the genus in Utah (e.g., Allred 1982). It is far beyond the expected range of this largely tropical and subtropical genus.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Biology
Longino and Booher (2019) - The senior author lives in a dense urban neighborhood in Salt Lake City, Salt Lake County, Utah, USA, near the University of Utah campus. It is an older neighborhood (“The Avenues”) that has been developed as housing since the late 1800s. The houses are surrounded by small yards, with the typical mix of lawns and ornamental plantings. Regular summer irrigation keeps the city green. There are many street trees, and the Salt Lake Valley is now filled with a large urban forest. This forest is about 150 years old, replacing the native sagebrush/grassland habitat that was largely treeless. The senior author has a small raised-bed garden, with potting soil about 20 cm deep. On the evening of 13 August 2018, just after dark, he was closely examining the surface of this garden, and observed 4 Strumigenys workers. Other foraging ants in the vicinity were Tetramorium immigrans, Brachymyrmex depilis, Solenopsis molesta, and Formica neoclara. The next night, several liters of soil were excavated to a depth of approximately 10 cm beneath where the foragers had been sseen. A total of 66 workers (a few with small larvae) and 6 winged queens were scattered in the soil.

This new species is likely a relict, like Strumigenys reliquia and others, that had retreated to subterranean microsites and thus escaped detection by entomologists. But human activity has created what is effectively a temperate broadleaf deciduous forest. Summer irrigation creates many square kilometers of habitat with warm, moist leaf litter and garden soil. This species may be experiencing a Renaissance, reemerging after a long retreat belowground. In this case, the creation of an urban forest was not a disruption or displacement of its native habitat, but an expansion.

Nomenclature

 *  ananeotes. Strumigenys ananeotes Longino & Booher, 2019: 498, fig. 1 (w.q.) U.S.A.

Description
The naming of this species was established description of this species was with images and a diagnosis.

Etymology
Meaning “newly emerged.”

References based on Global Ant Biodiversity Informatics

 * Longino J. T., and D. B. Booher. 2019. Expect the unexpected: a new ant from a backyard in Utah. Western North American Naturalist 79(4): 496–499.