Temnothorax nitens (Emery, Mayr, 1861

Ward, P. S., 2005, A synoptic review of the ants of California (Hymenoptera: Formicidae)., Zootaxa 936, pp. 1-68 : 17-18

Temnothorax nitens (Emery , 1895d)

(Figure 8)

Leptothorax nitens Emery 1895d: 322. Holotype worker, American Fork Canon , Utah [ USNM] [Examined]

Leptothorax nitens var. mariposa Wheeler 1917a: 507. Nine syntype workers, Camp Curry, Yosemite , California [ LACM, MCZC] [Examined] Syn. nov.

Leptothorax mariposa Wheeler ; Cole 1958c: 536. Raised to species.

Leptothorax melinus Mackay 2000: 368. Holotype worker, Beartrap Cyn. , Socorro Co., New Mexico, 2286 m (W. Mackay #16889 ) [ MCZC] [Examined]. Two paratype workers in LACM (same data) also examined. Syn. nov.

Temnothorax mariposa (Wheeler) ; Bolton 2003: 271. First combination in Temnothorax .

Temnothorax melinus (Mackay) ; Bolton 2003: 271. First combination in Temnothorax .

Temnothorax nitens (Emery) ; Bolton 2003: 271. First combination in Temnothorax .

Comments. T. nitens is a common western United States species characterized by a strongly cuneate (wedge-shaped) petiole, as seen in profile (Fig. 8). Body color varies from pale yellow to medium brown. Integument sculpture tends to be light; the head and mesosoma are finely reticulate-foveolate, with extensive shiny areas usually on the front of the head and occasionally on the mesosoma dorsum. The propodeal spines are variable, relatively short but better developed (on average) than in T. andrei , and usually as prominent as the anteroventral petiolar process, or more so (Figure 8). In the holotype worker of T. nitens the mesosoma dorsum is smooth and shiny centrally, but as noted by others (Wheeler 1903d; Cole 1958c) the head and mesosomal sculpture is highly variable in this species, and both shiny and more heavily sculptured workers can be found in the same nest. I have also observed this in California populations from the Sierra Nevada. The California workers with a shiny promesonotum tend to have weak longitudinal carinulae encroaching anteriorly and laterally, as in the T. nitens type.

Mackay’s (2000) treatment of T. nitens is inconsistent. On the one hand he seems to accept a broad concept of the species, showing it as having a wide distribution in western North America, accepting the previous synonymy of heathii and occidentalis under T. nitens (incorrectly, as it turns out -see under T. andrei ), and citing biological data from a diverse selection of localities. On the other hand, he describes a colony series from New Mexico as a new species ( melinus ), even though it falls well within the ambit of T. nitens (sensu lato). Restricting the use of the name T. nitens to workers with an especially shiny mesosoma is difficult to justify, given the patterns of intranidal variation described above. It seems more reasonable to treat it as a polytypic species, with variable effacement of the mesosomal sculpture.

T. mariposa was originally described as a variety of T. nitens . It was synonymized under that species by Creighton (1950a), and later resurrected by Cole (1958c) and raised to species. Cole’s argument was that both forms co-occurred in the Yosemite region without intergrading. But examination of a large series of nitens-like specimens from throughout the California Sierra Nevada challenges this thesis. It leads me to the conclusion that T. mariposa simply connotes larger individuals of T. nitens which have correspondingly broader heads and a tendency towards darker body color and coarser sculpture on the side of the mesosoma. There is no evidence of a gap in this size variation (nor in the correlated variation in shape, color and sculpture). The LACM collection has nitens-like nest series collected by Cole at Yosemite . His accessions 136, 184, 198, 201, 230, 231 and 233 are identified as “ nitens ” and 239 as “ mariposa ”. The “ nitens ” series are collectively smaller and more lightly sculptured than accession 239, but accessions 230, 231 and 233 have workers approaching those of 239 in size and sculpture. Moreover, the syntypes of T. mariposa (LACM, MCZC) agree more closely with the majority series (136 to 233) than with 239, so Cole’s attributions and conclusions are difficult to justify.