Veromessor pseudolariversi

Veromessor pseudolariversi workers are solitary, nocturnal foragers. Nests are usually polydomous and range from an entrance lacking a tumulus up to tumuli 10–15 cm in diameter (R.A. Johnson, pers. obs.). Colonies reach up to about 1,000 workers, and they are presumably monogynous. Workers are mostly monomorphic. Snelling and George (1979) collected both Veromessor lariversi and V. pseudolariversi in California, and they indicated that colonies appear to aestivate during summer months. It seems more likely that these authors observed inactive colonies given that both RAJ and MLB have observed V. pseudolariversi foraging in June.

Worker
This species is uniquely characterized by the following combination of features:
 * 1) light yellowish to yellowish-orange or yellowish-red, gaster sometimes slightly darker
 * 2) medial lobe of clypeus arugose, smooth and shining, not thick and protuberant in profile, not elevated above lateral lobes in frontal view
 * 3) mandibles with 7 teeth
 * 4) dorsal base of scape not flattened, slightly widened; maximum basal width of scape less than maximum preapical width
 * 5) MOD distinctly greater then OMD, OI > 32.0
 * 6) cephalic dorsum mostly smooth and shining with scattered piligerous punctures between few discontinuous, medial longitudinal rugae that weaken laterally and disappear posterior to eyes, posterior margin smooth and shining, rugae more coarse and well-defined in front of eyes
 * 7) psammophore well developed; consisting of J-shaped hairs arranged in a distinct row around the outer margin of ventral surface of the head capsule
 * 8) dorsum of pronotum weakly roughened and shining to lineogranulate or with few weak discontinuous irregular transverse rugae; sides of pronotum weakly to moderately punctulate-granulate, weakly shining, between few coarse longitudinal rugae; mesonotum with piligerous punctures to moderately punctulate-granulate, weakly shining to shining; mesopleura with moderately coarse, wavy to irregular, longitudinal rugae
 * 9) sides of propodeum weakly to moderately punctulate-granulate between few longitudinal or oblique rugae; propodeal spines divergent, elongate-triangular, acuminate, length similar to width at base, less than the distance between their bases, and length < 0.5× MOD; infraspinal facet weakly coriarious, weakly shining; propodeal declivity smooth and shining
 * 10) metasternal process higher than long, apex subangulate. Additionally, in profile, the anteroventral margin of postpetiole interrupted by a transverse ridge, appearing as a minute process, margin weakly concave anterior to process (Figures 29D–F, 42)

Queen
This caste is diagnosed by the following combination of features:
 * 1) mostly concolorous yellowish-brown to medium orangish-brown
 * 2) medial lobe of clypeus not thick and protuberant in profile, not elevated above lateral lobes in frontal view, medial lobe mostly smooth and arugose with numerous micropunctures to coriarious
 * 3) mandibles with 7 teeth
 * 4) dorsal base of scape weakly flattened, weakly widened; maximum basal width of scape less than maximum preapical width
 * 5) MOD distinctly greater than OMD
 * 6) cephalic dorsum with prominent longitudinal rugae adjacent to midline, above and below eyes, and on malar area; rugae lacking posterior to ocelli, posterior margin mostly smooth and shining
 * 7) psammophore well developed
 * 8) sides of pronotum moderately granulate between fine longitudinal rugae; mesoscutum smooth and shining, sometimes with faint rugae and scattered piligerous punctures; mesoscutellum smooth and strongly shining; mesospleura roughened and dull between wavy mostly longitudinal rugae, rugae faint to disappearing along posterodorsal margin of katepisternum
 * 9) propodeum moderately coriarious between longitudinal and oblique rugae; propodeal spines triangular, about as long as width at base, length shorter than the distance between their bases; infraspinal facet and propodeal declivity weakly coriarious, weakly shining to shining
 * 10) metasternal process higher than long, apex rounded. Additionally, in profile, the anteroventral margin of postpetiole interrupted by a transverse ridge, appearing as a minute process, margin weakly concave anterior to process (Figure 43)

Male
This caste is diagnosed by the following combination of features:
 * 1) dark brownish-black
 * 2) medial lobe of clypeus with several irregular longitudinal rugae with prominent medial carina that bifurcates near anterior margin
 * 3) preapical tooth small; mandibles with 1–2 minute teeth basad of preapical tooth
 * 4) in frontal view, anterior ocellus slightly above level of top of eyes
 * 5) mesopleura dull to weakly shining; anepisternum with fine longitudinal rugae, katepisternum with fine rugae that traverse ventrally from anterodorsal margin then curve posterad to posterior margin
 * 6) propodeum with moderately strong rugae, interrugae moderately coriarious; propodeal spines consist of denticles
 * 7) metasternal process elongate, digitiform
 * 8) subpetiolar process triangular, slightly longer than high. Additionally, in profile, ventral margin of postpetiole discontinuous with margin interrupted by a minute process anterad, margin weakly concave anterior to process (Figures 1H, 44)

Discussion
Veromessor pseudolariversi is broadly sympatric with several congeners including Veromessor smithi, Veromessor lariversi and Veromessor lobognathus. Veromessor pseudolariversi workers are separated from V. lobognathus and V. smithi by:
 * 1) smaller size (HW = 0.93–1.37 mm)
 * 2) body concolorous light yellowish to yellowish-orange or yellowish red, gaster often slightly darker
 * 3) maximum basal width of scape less than maximum preapical width
 * 4) mandibles with 7 teeth

For V. lobognathus and V. smithi:
 * 1) larger in size (HW = 1.28–1.82 mm)
 * 2) concolorous orangish-brown to rust colored
 * 3) maximum basal width of scape greater than maximum preapical width
 * 4) mandibles with 8 teeth

Veromessor pseudolariversi is most similar to the closely related V. lariversi, as reflected by the fact that numerous series of V. pseudolariversi were misidentified as V. lariversi. However, these two species display consistent differences in morphology. Morphological differences that separate the two species include that workers of V. pseudolariversi:
 * 1) in profile, anteroventral margin of postpetiole discontinuous with margin interrupted by a minute process, margin concave anterior to process (Figure 29D)
 * 2) in dorsal view and in profile, the pronotum with discontinuous to continuous, irregular, transverse rugae; dorsum of mesonotum with one to few weak, irregular, usually discontinuous, longitudinal rugae (Figure 29E–F)
 * 3) a relatively larger eye with more facets (Figure 30)

For workers of V. lariversi:
 * 1) in profile, ventral margin of postpetiole continuous, lacking a minute process (Figure 29A)
 * 2) in dorsal view and in profile, the pronotum and mesonotum arugose, weakly to strongly coriarious to punctulate-granulate (Figure 29B–C)
 * 3) a relatively smaller eye with fewer facets (Figure 30)

Queens and males of the two species also differ in size. Worker allometry is similar for both species, but queens of V. lariversi are distinctly larger than those of V. pseudolariversi, but their males are smaller (Figure 33). A molecular phylogeny that used UCEs shows that specimens that can be identified as V. lariversi and V. pseudolariversi using the above characters form sister but divergent, reciprocally monophyletic lineages, including specimens occurring in sympatry at Fort Churchill State Historic Park in Lyon County, Nevada (M.L. Borowiec, unpub. data).

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

Biology
The biology of V. lariversi and V. pseudolariversi are probably similar, but it is difficult to ascribe published information to one species or the other because series were not referenced in papers, voucher series were not collected, or series were absent from loans that were examined. The following information on biology includes only that which could be verified from examined series of V. pseudolariversi or field observations.

Gland chemistry has not been examined in V. pseudolariversi. Like other small-colony congeners, workers of V. pseudolariversi have a small pygidial gland reservoir and lack a textured tergal cuticle (Hölldobler et al., 2013).

Mating flights have not been observed, but males were collected on June 11 and dealate queens were found on the ground at night and early morning on 29 June–3 July, indicating that mating flights occur during summer, probably during pre-dawn hours. Cole (1963) found two dealate queens in one excavated nest, but it is unclear if this record was for V. lariversi or V. pseudolariversi.

Veromessor pseudolariversi is a mid-elevation species of the Great Basin Desert that occurs at elevations from 1,145–1,305 m. This species occurs in the Great Basin shrub steppe, Mohave desert, and Western short grasslands ecoregions, as defined by by Olson et al. (2001) (Figure 41B).

Nomenclature

 * . Veromessor pseudolariversi Johnson, Borowiec, Snelling & Cole, 2022: 80, figs 1H, 29D–F, 41B, 42–44 (w.q.m.) UNITED STATES (Nevada).

Type Material

 * Holotype worker [USNM: CASENT0923119]: UNITED STATES, Nevada: Nye County, 7 mi SSE Beatty, 36o49’N 116o44’W, 3000’ (909 m), 5 April 1970 (G.C. & J. Wheeler NEV#782A).
 * Paratypes, same data as holotype: CASC (10 workers), LACM (19 worker), MCZC (12 workers), MLBC (6 workers), NHMW (2 workers), RAJC (40 workers), UAIC (6 workers), UCDC (6 workers), USNM (16 workers).