Strumigenys subtilis

Strumigenys subtilis is known from a single specimen collected during a survey of the ant fauna of the Mohave National Preserve. Strumigenys subtilis is likely an inquiline or social parasite as it shares several common characters with other presumed or known Strumigenys inquilines: Strumigenys inopina, Strumigenys inquilina and Strumigenys subnuda. Shared characters include reduced sculpture, small or absent spongiform appendages, and simple non-expanded setae (MacGown & Hill 2010; Deyrup & Cover 1998). However, it is not likely these expected inquiline species are closely related. The unusual and uncommon character of the peripheral groove and similar dentition as species in the clypeata group suggest S. subtilis is potentially a member of this group. However, no other members of the clypeata group have ranges that extend much further west than eastern Texas, and several other morphological differences, e.g. short basal gastral costulae, are not consistent with the clypeata group (Bolton 2000).

Identification
Strumigenys subtilis is the only western species possessing a narrow peripheral groove along the free margin of the clypeus and highly reduced spongiform appendages. All eastern USA species with a peripheral groove also have well developed lateral petiolar and post-petiolar spongiform appendages; these spongiform appendages are reduced to narrow cuticular lamellae in S. subtilis. Strumigenys subtilis superficially resembles Strumigenys inopina, a southeastern USA species only known from a few queens and suspected to be a social parasite, but is easily distinguished by the presence of short basigastral costulae in S. subtilis (in S. inopina costulae are absent) (Bolton 2000) (Booher, 2021).

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

Nomenclature

 * . Strumigenys subtilis Booher, 2021: 242, fig. 42 (q.) UNITED STATES.

Type Material

 * Holotype Queen. USA, California, San Bernardino County, 1 mile west of Pichalka Spring, Clark Mountains, blackbush scrub, pitfall trap, 35.5185 -115.64213, 4 January 2006, 4600 ft, Collector J. des Lauriers, unique specimen identifier (casent0104307) [PSWC].