Monomorium marjoriae

Known only from the type material. Nothing is known about the biology of .

Identification
DuBois (1986) - A member of the Monomorium minimum species group. Queen Winged; scutum and scutellum not depressed; metanotum (in lateral view) projecting to level of propodeum and scutellum; propodeum angular (basal face 2 X length of declivitous face). Worker Propodeum angular (basal face 2 X length of declivitous face); mesopleuron not punctuate.

Monomorium marjoriae is most likely to be confused with Monomorium cyaneum or Monomorium compressum which may occur in similar habitats. Additionally, M. marjoriae closely resembles Monomorium ebeninum in habitus; however, these species do not appear to overlap. Queens of M. marjoriae may be separated from those of M. compressum and M. ebeninum since in the latter two species the scutum and scutellum are concave or flat. Queens of M. marjoriae may be separated from those of M. cyaneum since the latter are wingless and the former have a propodeum with the length of the basal face 2 X the length of the declivitous face. Workers of M. marjoriae may be separated from workers of these other species since they possess a propodeum with the basal face length 2 X the declivitous face length.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Nomenclature

 *  marjoriae. Monomorium marjoriae DuBois, 1986: 111, figs. 149-154 (w.q.) MEXICO.

Worker
Head. (representing type locality; N=2) HL 0.55-0.61 (0.58), HW 0.45-0.46 (0.46), SL 0.41-0.45 (0.43), EL 0.08-0.09 (0.08), MOD 0.05-0.06 (0.06). Structure—CI 75-82 (78), SIL 74-75 (74), SIW 89-98 (94). Scape reaching or surpassing occiput by an amount less than length of pedicel. Pilosity—Setae erect to subdecumbent on clypeus, frons, gular region, mandible, and occiput, decumbent to appressed elsewhere. Alitrunk. PW 0.26-0.28 (0.27), PL 0.24-0.25 (0.24), WL 0.65-0.68 (0.66). Structure—Propedeum angular, basal face 2X length of declivitous face. PI 35-38 (36). Postpetiole. Moderately dense, non-piliferous punctures on posterior surface of node. Color. Head brown to dark brown, mandible and antenna brown to yellow brown. Alitrunk brown, legs yellow brown to yellow. Petiole, postpetiole, and gaster brown to dark brown. All setae white.

Queen
As described for Monomorium minimum except as follows. Head: (representing type locality; N=3) HL 0.75-0.81 (0.78) {0.81}, HW 064-0.68 (0.67) {0.68}, SL 0.52-0.61 (0.56) {0.61}, IOD 0.16-0.18 (0.17) {0.17}, OD 0.04-0.05 (0.05) {0.05}, EL 0.16-0.22 (0.19) {0.22}, MOD 0.12-0.17 (0.14) {0.17}. Structure—CI 84-87 (85) {84}, SIL 67-75 (72) {75}, SIW 76-90 (84) {90}. Side of head straight. Scape reaching or surpassing occiput by less than length of pedicel. Pilosity—Setae erect to subdecumbent on clypeus, frons, gular region, mandible, and occiput, decumbent to appressed elsewhere. Sculpture—Small, parallel, longitudinal rugae beginning all along lateral margin of clypeus, extending past antennal insertion, and converging with frontal carina. Several small, parallel, longitudinal rugae beginning between clypeal teeth, extending to level of antennal insertion. Several small, parallel, longitudinal rugae beginning between frontal carinae (near posterior edge of carinae) and extending towards (but not reaching) anterior ocellus. Alitrunk. PW 0.40-0.48 (0.43) {0.48}, PL 0.26-0.40 (0.34) {0.26}, WL 1.30-1.40 (1.35) {1.30}. Structure—Mesopleural suture deflected dorsally at each end (resulting in U-shaped suture), with pits lacking on both ends. Propodeum angular, basal face 2 X length of declivitous face. PI 20-30 (26) {20}. Pilosity—Fewer than 30 erect to suberect setae projecting above dorsal outline of alitrunk. PETIOLE. Setae appressed on anterior surface of node, suberect to erect (a few decumbent) on side, dorsum, and posterior surface of node, absent elsewhere. Postpetiole: Setae appressed on anterior surface of node, suberect to erect elsewhere (including venter). Anterior surface and dorsum of node smooth and shining with small piliferous punctures; remainder covered with, moderately dense, non-piliferous punctures. Gaster: Setae of first gastral tergite not reaching level of dorsum of postpetiolar node. Color: Head (including mandible and antenna) brown to dark brown. Alitrunk brown to dark brown, legs brown to yellow brown. Petiole, postpetiole, and gaster brown to dark brown. All setae white.

Type Material
Holotype Queen: Mexico. Nayarit; Punga, May 26, 1923, H. C. Millender. Holotype bears red, handwritten label: Monomorium marjoriae Holotype M. DuBois 1983. Two paratype queens and 9 paratype workers collected with holotype. All paratypes bear blue, handwritten labels: Monomorium marjoriae Paratype M. DuBois 1983.

Etymology
This species is named in honor of my mother, Marjorie A. (Black) DuBois.

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * DuBois M. B. 1986. A revision of the native New World species of the ant genus Monomorium (minimum group) (Hymenoptera: Formicidae). Univ. Kans. Sci. Bull. 53: 65-119
 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Flores-Maldonado K. Y., S. A. Phillips, and G. Sanchez-Ramos. 1999. The myrmecofauna (Hymenoptera: Formicidae) along an altitudinal gradient in the Sierra Madre Oriental of Northeastern Mexico. The Southwestern Naturalist 44(4): 457-461.
 * Flores-Maldonado, K. Y., S. A. Phillips-Jr, and G. Sanchez-Ramos. 1999. The myrmecofauna (Hymenoptera: Formicidae) along an altitudinal gradient in the Sierra Madre Oriental of Northeastern Mexico. The Southwestern Naturalist 44: 457-461.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133