Comprehensive Description

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Neivamyrmex microps Borgmeier HNS , 1955

Figures 8, 39, 54, 68, 81, 102, 103, 129, 140

Neivamyrmex microps Borgmeier HNS , 1955: 635 (m). U. S. A. , Arizona , Phoenix ( USNM ). Watkins, 1972: 352. Watkins, 1976: 25 .

The worker caste has not been previously described.


Worker. Eye absent; antennal scape not extending to midlength of head; head with numerous suberect hairs, but no erect hairs; propodeal dorsum smooth and shiny, distinctly longer than declivitous face, latter smooth and shiny; petiole node longer than broad in dorsal view, sides slightly convex; postpetiole slightly wider than long, disc smooth and shiny, sides weakly sculptured.


Worker, measurements (mm) (n = 12): HW 0.59; HL 0.73; SL 0.34; SW 0.11; PW 0.22; ML 0.36; PL 0.27; PpW 0.29; PpL 0.22; HFL 0.50; HFW 0.15. Indices: CI 70 - 85 FI 28 - 39; SI 39 - 51

Head distinctly longer than broad; smooth and shiny with only scattered small punctures. Eye absent. Dorsolateral corners slightly angulate, preoccipital carina weak. Scape not reaching middle of head length, 3 x as long as greatest breadth, broad distad, abruptly narrowed at base. Subantennal lamella well developed. Head without erect hairs, but with numerous suberect hairs. Mandible triangular, upper margin straight and distinctly angulate at juncture with masticatory margin; upper margin with distinct small distal tooth (Fig. 7).

Mesosomal dorsum smooth and shiny; promesonotal suture indistinct; metanotal groove distinct. Propodeal dorsum smooth and shiny, distinctly longer than declivitous face, latter smooth and shiny. Metafemur stout.

Petiole node longer than broad in dorsal view with sides slightly convex and narrowing anteriorly; evenly convex in lateral view; sides slightly granulate; subpetiolar tooth minute. Postpetiole slightly wider than long, dorsum smooth and shiny, sides lightly granulopunctate.

Gaster smooth and shiny on first tergum, second segment weakly sculptured and less shiny.


UNITED STATES: Known only from Arizona, but almost certainly extends into adjacent eastern California and south into MEXICO.


UNITED STATES , ARIZONA , Maricopa Co. : Phoenix ( USNM ) (m) ; Scottsdale ( GCSC , LAAG , LACM ) (m) ; 4 Peaks Rd. ( Mazatzal Mts. ), 5 mi E Hwy. 87 ( RAJC , GCSC , LACM ) (w) . Pinal Co. : Red Rock ( 34.30 ° N110.19 ° W ( ARSU ) (m) . Pima Co. : Tucson , in house ( UNAR ) (m) . Santa Cruz Co. : Madera Canyon , 4000 ', Santa Rita Mts. ( LACM ) (m) . Yuma Co. : Hoodoo Well , Kofa Mts. ( GCSC ) (m) .


Neivamyrmex microps HNS is one of a number of species, the males of which all have a distally bifurcate volsella, that possess minute tubercles on the outer face of the volsella (much as in Fig. 140). The number and distribution of these tubercles may be consistent and characteristic from species to species, but we have not investigated this matter in detail, nor have we examined all species with bifurcate volsellae. At this stage we can only stipulate that they are not present in all species with bifurcate volsellae. Among the United States species we can affirm their presence in males of N. microps HNS , N. minor HNS , N. ndeh HNS and N. swainsonii HNS . They are absent in males of N. andrei HNS and N. fuscipennis HNS . In the case of N. microps HNS these tubercles are sufficiently numerous that three or four are visible within the apical crotch as minute teeth.

In the original description of this species Borgmeier incorrectly cited the collector of the type specimen as “ R. H. Randall ”; the correct name is R. H. Crandall. For many years known only from the type specimen, this species has recently been collected again in a number of Arizona localities. Although we now know that N. microps HNS has a fairly extensive range within Arizona, it will likely continue to be a rarely collected species. Current records indicate that this species inhabits a wide range of habitats, having been found in areas ranging from Creosote scrub to Oak woodland, with an elevational range between 1000 and 4000 feet.

Based on circumstantial evidence, we have associated the above described workers with this species. They were collected in Maricopa County, along 4 Peaks Road by R. A. Johnson, 27 March 1993. These workers belong to the correct species group and and the known distribution makes this association probable. Workers may be confused with those of N. leonardi HNS , but may be differentiated by the less well developed mandibular teeth, the longer, narrower postpetiole, and the less convex mesosomal profile.

Nothing is known of the biology of this species. However, label data indicate that the activity period for this species closely coincides with the summer / fall monsoon season in Arizona.


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