Temnothorax subditivus

Temnothorax subditivus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Temnothorax
Species group:	salvini
Species subgroup:	subditivus
Species:	T. subditivus
Binomial name
Temnothorax subditivus (Wheeler, W.M., 1903) Specimen Label
Synonyms
Macromischa flavitarsis Mann, 1920 Macromischa laevissima Wheeler, W.M., 1911 Macromischa luciliae Mann, 1935

Found in open shrub and woodland habitats.

Identification

Prebus (2021) – A member of the subditivus group of the Temnothorax salvini clade. Temnothorax subditivus can be separated from all other species in the salvini clade by the following character combination: posterior margin of head convex; antennal scape moderately long, surpassing the posterior margin of the head by about the maximum width of the antennal scape; in profile view, dorsum of mesosoma strongly convex; pronotal declivity not marked by an angle as it transitions from the anterior face of the pronotum to the dorsal face; propodeum not depressed below the level of the promesonotum; propodeal spines as long as or longer than the propodeal declivity, directed posterodorsally, and straight; hind femora moderately to strongly incrassate; petiolar node node robust and erect, squamiform, and not leaning posteriorly over the caudal cylinder of the petiole; postpetiole moderately broad: greater than 1.7 times the width of the caudal cylinder of the petiole; setae on head, mesosoma, waist segments and gaster erect, moderately long, sparse and blunt (never long and tapering).

Similar species: Temnothorax subditivus is extremely variable across its vast range, and may be confused with Temnothorax goniops, Temnothorax pilicornis, Temnothorax tenuisculptus, and members of the augusti and pastinifer groups. It can be separated from all of the above, except the pastinifer group, by the extremely squamiform petiolar node, which in dorsal view is much broader than the caudal cylinder of the petiole. When viewed dorsally, the closely approximated propodeal spines, the bases of which are united by a transverse carina, will distinguish T. subditivus from all members of the pastinifer group.

Temnothorax subditivus has the largest range of any salvini clade speciesand is highly morphologically variable. Workers can be uniformly dark brown to uniformly yellow, densely sculptured to mostly smooth and shining.

Smith (1939) - The worker of Temnothorax subditiva can be readily distinguished by the peculiarly shaped petiole, the peduncle of which is at least twice the length of the petiolar node; the rather uniform brownish color of most of the body; the obsolescent or missing thoracic sutures; the slender antennal scapes; and the sculpturing of the body.

Keys including this Species

• Key to Temnothorax salvini clade workers

Distribution

Southern North America, all of Mesoamerica, parts of northern South America, and the Cayman Islands.

Latitudinal Distribution Pattern

Latitudinal Range: 30.78714° to 1.25°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).
Neotropical Region: Cayman Islands, Colombia, Costa Rica, Guatemala, Mexico, Nicaragua, Panama, Venezuela.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Habitat

Temnothorax subditivus inhabits dry forests and disturbed habitats from sea level to high elevations; also noted as occurring in shrub and open woodland habitats.

Biology

Prebus (2021) - Inhabiting dry forests and disturbed habitats, Temnothorax subditivus is often found nesting in hollow, dead vegetation, under the bark of trees, or in epiphytes, but may also be found in rock crevices and abandoned termite burrows (this study; Achury, Chacón de Ulloa & Arcila, 2008; Creighton, 1965; Escalante-Jiménez & Vasquez-Bolaños, 2015; Gutiérrez-Martínez & Naranjo, 2016; Pérez-Sánchez, Lattke & Viloria Petit, 2012; Rojas, Fragoso & Mackay, 2014; Wheeler, 1903a). Colonies are small, with 12 to 145 workers, and monogynous (Creighton, 1965). They are apparently trophic generalists, like many Temnothorax for which food preference is known, but favour insects (Creighton, 1965). The male pupae bear bizarre appendages with unknown function (Schumann, 1992).

Regional Notes

USA - Texas

In New Braunfels workers were found walking on the leaves of bushes, in Walnut Creek on a dead limb lying on the ground. I did not succeed in finding the nest which is probably small and not very populous. Since the above was written I have succeeded in finding a single nest of T. subditiva. This was a small cell excavated in the bark of a huge willow (Salix nigra) near Austin. The cell contained about twenty workers and resembled in every way the nests of our corticolous species of Leptothorax. (Wheeler 1903)

I have taken this species nesting, like certain species of Temnothorax, in the bark of large trees (willows) at Austin, Del Valle, and New Braunfels, Texas, and have specimens taken by J. A. Mitchell at Victoria and by R. A. Vickery at Harlingen, in the same state. (Wheeler 1931)

Mexico - Nuevo Leon

In April 1991, two complete colonies of Temnothorax subditivus, including about 80 workers, numerous larvae and one single queen each, were collected in a mountainous wood region near Monterrey (Nuevo Leon, Mexico) at an elevation of ca. 1600 m in dry wood sticks at the ground. (Schumann 1992).

A number of workers, females and males were taken by Dr. Elisabeth Skwarra from several colonies at Mirador, Mexico. One of these was nesting in a thorn of Acacia cornigera, the others in the stems of a Melastomaceous shrub, Conostegia xalapensis. Females and workers from another colony taken at Tlacocintlo were nesting in a Tillandsia pruinosa. (Wheeler 1931)

Costa Rica

Temnothorax subditivus occurs in seasonally dry habitats. It inhabits scrubby vegetation and roadsides, nesting in small dead twigs or other dead plant cavities. Colonies are monogynous.

I have collected this species four times in Costa Rica, as follows:

• Santa Rosa National Park, ridge between Playa Naranjo and Nancite: xeric scrub on rocky ridge; nest in dead branch; branch was dry and brittle.

• Road from Pan American Highway to Monteverde, La Pita to Guacimal (below 500m elevation): three different collections from scrubby roadside vegetation, sweep samples and strays from tree trunks.

Longino [1]

Columbia - Santa Marta

I..have collected the species in the Santa Marta region of Colombia. I found a small, monogynous colony under loose bark on a 2-3cm dia dead branch. The area of the nest was no more than 1x2cm. Crematogaster carinata were nesting throughout the same dead branch. Longino [2]

Nesting Habits

Small dead twigs, on living living plants or on the ground, and in other (dead) plant cavities.

Association with Other Organisms

 Explore: Show all Associate data or Search these data. See also a list of all data tables or learn how data is managed.

This species is a xenobiont for the ant Crematogaster carinata (a xenobiont).

Morphology

Pupae of this caste have been found to bear some unusual appendages. Schumann (1992): "Two translucent lateral projections, having their origin at the basis of the third femurs, arch forward around the wing buds. Their length is about 0,4 mm. In addition, two blunt appendages, originating from the postpetiolar region, point forward, on both sides of the petiole. Below these projections, two short appendages on both sides of the petiole can be seen. Their length is about 0,15 mm (Fig. 2). The projections are translucent and filled with the pupal liquid. With higher magnification their surface appears roughly sculptured as the result of a partly thickened cuticle. Histological studies have revealed that there are no cellular structures detectable inside any of these appendages. They seem to be part of the pupal cuticle (Billen, pers. comm.)"

Castes

Worker

Images from AntWeb

Worker. Specimen code casent0619368. Photographer Matthew Prebus, uploaded by Curator Matthew Prebus.	Owned by JTLC.

Worker. Specimen code casent0758299. Photographer Matthew Prebus, uploaded by Curator Matthew Prebus.	Owned by UNAM.

Worker. Specimen code casent0868474. Photographer Matthew Prebus, uploaded by Curator Matthew Prebus.	Owned by MMPC.

Queen

Images from AntWeb

Queen (alate/dealate). Specimen code casent0104743. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.

Male

Images from AntWeb

Male (alate). Specimen code casent0104744. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• subditivus. Macromischa subditiva Wheeler, W.M. 1903b: 99, fig. 5 (w.) U.S.A. Wheeler, W.M. 1931b: 15 (q.); Smith, M.R. 1939e: 504 (m.). Combination in Leptothorax: Baroni Urbani, 1978b: 512; in Temnothorax: Bolton, 2003: 272. Senior synonym of flavitarsis, laevissima, luciliae: Baroni Urbani, 1978b: 512. See also: Creighton, 1966a: 282.
• laevissima. Macromischa laevissima Wheeler, W.M. 1911h: 205 (w.) MEXICO. Junior synonym of subditivus: Baroni Urbani, 1978b: 512.
• flavitarsis. Macromischa (Macromischa) flavitarsis Mann, 1920: 420 (w.q.) GUATEMALA. Wheeler, W.M. 1931b: 14 (m.). Junior synonym of subditivus: Baroni Urbani, 1978b: 512.
• luciliae. Macromischa luciliae Mann, 1935, 35, fig. 1 (w.) GUATEMALA. Junior synonym of subditivus: Baroni Urbani, 1978b: 512.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Prebus (2021) - The high degree of morphological variability and broad range have led taxonomists to assign a large number of names to this species, but the phylogeny of this species shows a great deal of geographical structure, with a pectinate series from the northern part of the range to the southern part (Prebus in prep.). This pattern could be attributed to either isolation by distance or to a recent radiation of closely related species. Increased sampling along with species delimitation analysis across the range of T. subditivus should elucidate whether this taxon represents a broadly distributed morphologically and ecologically variable species or a species complex.

Description

Worker

Length 2-2.5 mm.

Head somewhat longer than broad, rounded at the posterior angles and convex above. Mandibles rather small, with three acute apical and three much smaller basal teeth. Clypeus short, broadly rounded in front, convex in the middle, with a prominent median carina running its full length and continued over the frontal area. Frontal area large, triangular, longer than broad. Antennae long, 12-jointed; scape extending beyond the posterior corner of the head to a distance equal to twice its breadth; first funicular joint nearly as long as the three succeeding joints together, joints 2-8 about as long as broad, two penultimate joints subequal, together as long as the terminal joint. Thorax short and thick-set, dorsum in profile convex, evenly rounded prothorax with broadly rounded angles, promesonotal suture very faintly, mesopinotal suture somewhat more distinctly indicated. Epinotum armed with two stout spines, which are very close together at their bases but diverge strongly outward, upward, and backward; epinotal declivity concave. Petiole long, with a conspicuously elongated peduncle which passes very abruptly into the transverse node; the latter is much compressed antero-posteriorly when seen in profile, the anterior and posterior surfaces being flattened and perpendicular, the summit of the node narrow and rounded when seen from behind, the edge of the node is horizontal and nearly straight. There is a small but distinct tooth on the ventral surface of the petiole near its anterior end. Postpetiole from above but little wider than the node of the petiole, fully twice as broad as long, rounded oblong; in profile it is nodiform, very convex dorsally, in both views showing a decided constriction at its insertion into the gaster. Gaster of the usual shape, with a long, powerful sting. Legs of the usual shape, with the femora conspicuously incrassated in the middle. There are no spurs on the middle and hind tibiae.

Head, including the mandibles and clypeus, subopaque, sharply longitudinally rugose; the rugae connected by subsidiary reticulate rugae on the base of the mandibles, cheeks, and sides of the head. Clypeus and frontal area more shining, the former with few rugae, especially near the middle. Thoracic dorsum shining, pleurae and epinoturn subopaque. Whole surface of thorax reticulate rugose, regularly in the opaque regions, more irregularly and more longitudinally on the shining dorsal surface. Petiole and postpetiole shining above, reticulate and subopaque on the ventral and lateral surfaces. Gaster very smooth and shining. Legs more opaque, finely but distinctly reticulate.

Head, thorax, and abdomen beset with sparse, erect, obtuse, silvery white hairs; antennae and legs with minute, appressed, pointed hairs of the same color.

Body black or, in immature specimens, very dark brown mandibles, antennae, legs and epinotal spines, tip of gaster, and sting yellow, scape and club of antennae, bases of epinotal spines, and greater portion of femora and tibiae infuscated.

Prebus (2021) - (n = 15): SL = 0.528-0.704 (0.610); FRS = 0.184-0.237 (0.209); CW = 0.569-0.712 (0.645); CWb = 0.525-0.657 (0.592); PoOC = 0.257-0.322 (0.285); CL = 0.644-0.810 (0.717); EL = 0.153-0.198 (0.172); EW = 0.117-0.146 (0.130); MD = 0.138-0.189 (0.164); WL = 0.745-1.003 (0.836); SPST = 0.247-0.368 (0.296); MPST = 0.255-0.318 (0.283); PEL = 0.301-0.417 (0.346); NOL = 0.168-0.240 (0.207); NOH = 0.100-0.174 (0.142); PEH = 0.201-0.277 (0.243); PPL = 0.120-0.166 (0.144); PPH = 0.148-0.206 (0.183); PW = 0.361-0.470 (0.419); SBPA = 0.117-0.167 (0.144); SPTI = 0.179-0.300 (0.247); PEW = 0.124-0.163 (0.143); PNW = 0.212-0.298 (0.251); PPW = 0.246-0.32 (0.285); HFL = 0.574-0.837 (0.670); HFWmax = 0.138-0.208 (0.168); HFWmin = 0.049-0.066 (0.055); CS = 0.848-1.062 (0.951); ES = 0.213-0.269 (0.237); SI = 95-109 (103); OI = 24-26 (25); CI = 79-86 (83); WLI = 134-153 (141); SBI = 21-28 (24); PSI = 30-45 (35); PWI = 179-216 (199); PLI = 218-273 (241); NI = 117-210 (148); PNWI = 160-208 (175); NLI = 53-70 (60); FI = 261-359 (304).

In full-face view, head subquadrate, slightly longer than broad (CI 79-86). Mandibles densely, finely striate but shining and armed with five teeth: the apical-most well developed and acute, followed by a less developed preapical tooth and three equally developed smaller teeth. Anterior clypeal margin evenly convex medially. Antennal scapes moderately long: when fully retracted, surpassing the posterior margin of the head capsule by slightly more than the maximum width of the scape (SI 95-109). Antennae 12-segmented; antennal club of composed of three segments, with the apical-most segment longer than the preceding two in combination. Frontal carinae long, extending past the antennal toruli by about three and a half times the maximum width of the antennal scape. Compound eyes moderately protruding past the lateral margins of the head capsule. Lateral margin of head moderately convex, forming a continuous arc from the mandibular insertions to the posterior margin of the head. Posterior head margin convex, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and moderately large (OI 24-26), with 14 ommatidia in longest row. Pronotal declivity indistinct, but neck and anterior face of pronotum forming a ~120° angle. Mesosoma predominantly evenly convex from where it joins the pronotal neck to the propodeal spines; propodeum very weakly depressed, so that the dorsal margin dips slightly anterior to the base of the propodeal spines. Promesonotal suture extending from the posterior margin of the procoxal insertion only to the mesothoracic spiracle, which is weakly developed. Metanotal groove visible as a disruption of the sculpture laterally from where it arises between the mid- and hind coxae to where it ends in the poorly developed metathoracic spiracle, which is nearly indistinguishable against the ground sculpture. Propodeal spiracle poorly developed, directed posterolaterally, and separated from the propodeal declivity by about five spiracle diameters. Propodeal spines well developed and moderately long (PSI 30-45), about as long as the propodeal declivity, flared at the base, straight, directed posterodorsally, and acute. Propodeal declivity flat, forming a rounded ~110° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole long (PLI 218-273), without tubercles anterodorsally. Subpetiolar process in the form of a small, acute tooth, the ventral face of the petiole weakly bulging below the petiolar node. Petiolar peduncle very long: comprising about three quarters of the petiole. Petiolar node squamiform: node arising abruptly from the petiolar peduncle, forming a rounded ~100° angle with it; anterior face rounding evenly into the very short dorsal face, which is strongly convex; dorsal face rounding evenly into the posterior face, which forms a ~90° angle with the caudal cylinder. Postpetiole evenly rounded anteriorly, flattened dorsally, and lobed ventrally. Sting extremely well developed: longer than the first gastral sternite.

In dorsal view, humeri well developed and distinct: rounded and wider than the rest of the mesosoma; mesothoracic spiracles weakly protruding past the lateral margins of the mesosoma, visible as slight angles where the pronotum meets the mesonotum. Metanotal groove absent: mesonotum and propodeum completely fused and lateral margins converging evenly to the bases of the propodeal spines. Propodeal spines narrowly approximated basally and joined by a transverse welt; diverging apically, their apices separated from each other by about their length, the negative space between them V shaped. Petiolar peduncle with spiracles slightly protruding past the lateral margins. Petiolar node squamiform: transversely ovular when viewed dorsally; node much wider than the peduncle, and a little less than twice as broad as the caudal cylinder. Postpetiole narrow to moderately broad (PWI 179-216) and campaniform, articulating with most of the anterior margin of the gaster, but leaving angulate corners of the gaster exposed on each side. Anterior margin of the postpetiole weakly convex, nearly flat, and evenly rounding into the lateral margins, which diverge slightly to the angulate posterior corners; posterior margin broadly concave. Metafemur moderately to strongly incrassate (FI 261-359).

Sculpture: median clypeal carina present, extending posteriorly to the level of the antennal toruli, and flanked on either side by two equally strong carinae. Lateral clypeal lobes with additional, weaker carinae; ground sculpture shining through weak costulae. Antennal scapes dully shining through weak areolate ground sculpture. Cephalic dorsum predominantly with weak costae, but with indications of weak areolae laterally; median strip and posterior half of the head smooth and shining. Lateral surfaces shallowly areolate, but with stronger rugae surrounding the compound eye, and between the eye and the mandibular insertion. Ventral surface of head smooth and shining, with weak costulae. Mesosoma with areolate sculpture on the pronotal neck. Lateral faces of mesosoma with weak areolae and costulae, which become stronger on the lateral face of the propodeum and meso- and metapleuron. Propodeal declivity shining through shallow areolae. Dorsal surface of pronotum with very weak costulae and areolae, which becomes stronger laterally; the border between the pronotum and mesonotum indicated by a transverse strip of stronger sculpture. Remainder of the mesosoma smooth and shining medially, but with areolate sculpture laterally and with a transverse strip of areolate sculpture directly anterior to the base of the propodeal spines. Femora weakly shining through shallow areolate sculpture. Petiole and postpetiole predominantly smooth and shining; dorsum of the postpetiole with a strip of shallow areolate sculpture along the posterior border. Gaster smooth and shining, without spectral iridescence.

Setae: antennal scapes and funiculi with short, decumbent pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, erect, blunt-tipped setae, the longest of which are about the width of the compound eye. The head dorsum bears ~44, mesosoma ~34, petiole 10, postpetiole ~18, and first gastral tergite ~82 setae. Finer, blunt setae are present on the ventral surface of the head, propleuron, procoxae, and ventral surface of the gaster. Short, sparse pubescence present over the entire body, but is difficult to detect against the dense sculpture.

Color: Predominantly testaceous brown; tarsi and sting yellow.

Queen

Prebus (2021) - (n = 3): SL = 0.603-0.703 (0.644); FRS = 0.242-0.265 (0.253); CW = 0.732-0.812 (0.782); CWb = 0.673-0.752 (0.722); PoOC = 0.292-0.33 (0.305); CL = 0.765-0.838 (0.795); EL = 0.225-0.254 (0.244); EW = 0.166-0.196 (0.182); MD = 0.165-0.176 (0.170); WL = 1.187-1.320 (1.251); SPST = 0.307-0.402 (0.345); MPST = 0.345-0.379 (0.367); PEL = 0.390-0.440 (0.420); NOL = 0.209-0.288 (0.243); NOH = 0.181-0.195 (0.188); PEH = 0.323-0.342 (0.331); PPL = 0.180-0.224 (0.206); PPH = 0.269-0.305 (0.290); PW = 0.671-0.820 (0.741); SBPA = 0.339-0.408 (0.369); SPTI = 0.349-0.406 (0.370); PEW = 0.185-0.243 (0.212); PNW = 0.297-0.323 (0.307); PPW = 0.403-0.441 (0.416); HFL = 0.706-0.800 (0.740); HFWmax = 0.146-0.168 (0.157); HFWmin = 0.051-0.059 (0.055); CS = 1.056-1.160 (1.120); ES = 0.308-0.352 (0.335); SI = 83-95 (89); OI = 29-30 (30); CI = 88-96 (91); WLI = 166-178 (173); SBI = 48-55 (51); PSI = 25-30 (28); PWI = 166-218 (199); PLI = 192-217 (204); NI = 115-148 (129); PNWI = 133-163 (146); NLI = 53-67 (58); FI = 264-300 (284).

In full-face view, head subquadrate, slightly longer than broad (CI 88-96). Mandibles densely striate, dull, and armed with five teeth: the apical-most well developed, followed by a four roughly equally developed smaller teeth. Anterior clypeal margin very slightly emarginate medially. Antennal scapes moderately long: when fully retracted, just reaching the posterior margin of the head capsule (SI 83-95). Antennae 12-segmented; antennal club of composed of three segments, with the apical-most segment as long as than the preceding two in combination. Frontal carinae long, extending past the antennal toruli by about four times the maximum width of the antennal scape. Compound eyes moderately protruding past the lateral margins of the head capsule. Lateral margin of head evenly convex, converging evenly to the mandibular insertions. Posterior margin of head weakly convex, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and large (OI 29-30), with 18 ommatidia in longest row. Mesoscutum rounded evenly anteriorly, covering the dorsal surface of the pronotum, and flat dorsally. Mesoscutellum on the same level as the mesoscutum; posterior margin of metanotum extending past the posterior margin of the mesoscutellum. Propodeal spiracle weakly developed, directed posterolaterally, and separated from the propodeal declivity by about five spiracle diameters. Propodeal spines stout and well developed, but short (PSI 25-30), about half as long as the propodeal declivity, flared at the base, weakly downcurved, directed posteriorly, and acute. Propodeal declivity straight and flat, forming a rounded ~100° angle with the base of the propodeal spines. Propodeal lobes rounded and very weakly developed. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole long (PLI 192-217), without tubercles anterodorsally. Subpetiolar process in the form of a weakly developed, acute tooth, which grades evenly into the ventral margin of the petiole posteriorly. Petiolar peduncle very long: comprising about two thirds of the total length of the petiole. Petiolar node squamiform: node arising abruptly from the petiolar peduncle, forming a rounded ~120° angle with it; anterior face rounding evenly into the very short dorsal face, which is strongly convex; dorsal face rounding evenly into the posterior face, which forms a ~90° angle with the caudal cylinder. Postpetiole evenly rounded anteriorly, dorsal face bulging anterodorsally before flattening posteriorly; ventral surface lobed.

In dorsal view, mesoscutum covering pronotum anteriorly, but humeri visible laterally as rounded sclerites. Propodeal spines diverging basally, but parallel distally, their apices separated from each other by about two and a half times their length. Petiolar peduncle with spiracles protruding past the lateral margins, the peduncle broadened where they arise. Petiolar node squamiform: transversely oval when viewed dorsally; node much wider than the peduncle, and a about one and a half times as broad as the caudal cylinder. Postpetiole narrow to moderately broad (PWI 166-218), anteroposteriorly compressed, and subquadrate, articulating with most of the anterior margin of the gaster, leaving small, angulate margins on each side of the gaster exposed. Anterior margin of postpetiole very weakly convex, nearly flat, with corners evenly rounding into the lateral margins, which evenly diverge to the angulate posterior corners; posterior margin weakly concave.

Metafemur moderately incrassate (FI 264-300).

Sculpture: median clypeal carina present, extending nearly to the frontal triangle, and flanked by additional weaker carinae over weakly areolate ground sculpture. Antennal scapes areolate and weakly shining. Cephalic dorsum densely costate, over weak areolate sculpture. Lateral surface of head with denser rugae forming whorls around the compound eye and forming transverse reticulations between the compound eye and the mandibular insertions. Ventral surface of head weakly costulate. Pronotal neck areolate. Pronotum, propodeum, and posterior two thirds of the anepisternum and katepisternum sculptured like the cephalic dorsum; anterior thirds of anepisternum and katepisternum smooth and shining. Propodeal declivity shallowly areolate. Mesoscutum costulate. Mesoscutellum costulate, with a patch of smooth and shining sculpture posteromedially. Femora shining through weak areolate sculpture. Petiole weakly areolate, with the anterior face of the node smooth and shining, and the dorsum transversely striate. Dorsal surface of postpetiole shallowly areolate. Gaster smooth and shining, only faint traces of spectral iridescence on the first gastral tergite and sternite.

Setae: antennal scapes and funiculi with short, decumbent pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, erect, blunt-tipped setae, the longest of which are about a third of the width of the compound eye. Finer, blunt setae are present on the ventral surface of the head, propleuron, procoxae, and ventral surface of the gaster. Short, sparse pubescence present over the entire body, but is difficult to detect against the dense sculpture. Color: predominantly testaceous brown; tarsi yellow.

Wheeler (1931) - 3.5 mm. Head subrectangular, as broad as long, broader behind than in front, with convex posterior border. Thorax less than twice as long as broad, mesonotum nearly as broad as long, flattened above; scutellum nearly as long as the epinotum, which is short, with sloping base and vertical declivity; spines acute, stout at base, shorter than their distance apart. Postpetiole nearly 2 1/2 times as broad as long; gaster large, elliptical, with concave anterior border. Pilosity and coloration as in the worker, head and thorax more opaque, evenly longitudinally rugulose.

Male

Prebus (2021) - Male measurements & indices (n = 3): SL = 0.368–0.421 (0.402); FRS = 0.107–0.142 (0.126); CW = 0.505–0.537 (0.519); CWb = 0.439–0.473 (0.455); PoOC = 0.219–0.234 (0.225); CL = 0.503–0.529 (0.514); EL = 0.217–0.228 (0.222); EW = 0.175–0.191 (0.184); MD = 0.033–0.051 (0.040); WL = 0.810–0.877 (0.841); SPST = n/a; MPST = 0.268–0.295 (0.280); PEL = 0.273–0.289 (0.282); NOL = 0.151–0.186 (0.167); NOH = 0.039–0.072 (0.056); PEH = 0.134–0.161 (0.145); PPL = 0.123–0.154 (0.140); PPH = 0.170–0.181 (0.174); PW = 0.511–0.558 (0.537); SBPA = n/a; SPTI = n/a; PEW = 0.131–0.184 (0.149); PNW = 0.157–0.219 (0.182); PPW = 0.248–0.276 (0.261); HFL = 0.596–0.679 (0.634); HFWmax = 0.076–0.090 (0.083); HFWmin = 0.044–0.053 (0.048); CS = 0.694–0.738 (0.712); ES = 0.310–0.321 (0.314); SI = 81–96 (89); OI = 42–46 (44); CI = 86–90 (88); WLI = 179–190 (185); SBI = n/a; PSI = n/a; PWI = 150–195 (178); PLI = 188–222 (203); NI = 258–387 (313); PNWI = 119–127 (122); NLI = 55–64 (59); FI = 158–205 (175).

In full-face view, head subglobular, slightly longer than broad (CI 86–90). Mandibles smooth and shining and armed with five teeth: the apical-most well developed and acute, followed by a less developed preapical tooth and three equally developed smaller crenulae. Anterior clypeal margin evenly rounded medially. Antennal scapes moderately long: when fully retracted, just reaching the posterior margin of the head capsule (SI 81–96). Antennae 13-segmented; antennal club of composed of three segments, with the apical-most segment as long as than the preceding three in combination. Frontal carinae long, extending past the antennal toruli by about four times the maximum width of the antennal scape. Compound eyes strongly protruding past the lateral margins of the head capsule. Posterior margin of head strongly convex, not differentiated from lateral margins.

In profile view, compound eyes ovular and very large (OI 42–46), with 22 ommatidia in longest row. Mesoscutum rounded evenly anteriorly, covering the dorsal surface of the pronotum, and flat dorsally. Mesoscutellum inflated and much higher than the mesoscutum; posterior margin of mesoscutellum overhanging the posterior margin of the metanotum. Propodeal spiracle weakly developed, directed posterolaterally, and separated from the propodeal declivity by about four spiracle diameters. Propodeal spines absent. Propodeum evenly rounded. Propodeal lobes rounded and very weakly developed. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole long (PLI 188–222), without tubercles anterodorsally. Subpetiolar process absent; ventral margin of petiole weakly bulging medially. Petiolar peduncle very long: comprising about two thirds of the total length of the petiole. Petiolar node low and cuneiform: node evenly grading into the petiolar peduncle anteriorly; anterior face meeting the posterior face at a ~90 angle. Postpetiole evenly rounded anteriorly, flattened dorsally; ventral surface concave.

In dorsal view, mesoscutum covering pronotum anteriorly; humeri barely visible laterally. Propodeal spines absent. Petiolar peduncle with spiracles protruding past the lateral margins, the peduncle broadened where they arise. Petiolar node cuneiform: dorsum flat when viewed posterodorsally, and narrower than the caudal cylinder. Postpetiole narrow (PWI 150–195) and campaniform, articulating with most of the anterior margin of the gaster, leaving angulate margins on each side of the gaster exposed. Anterior margin of postpetiole weakly concave, nearly flat, with corners evenly rounding into the lateral margins, which evenly diverge to the angulate posterior corners; posterior margin weakly concave. Metafemur not incrassate (FI 158–205).

Sculpture: median clypeal carina present, extending nearly the level of the antennal toruli, and flanked by additional weaker carinae over smooth ground sculpture. Antennal scapes weakly areolate and shining. Cephalic dorsum densely areolate, with costulae radiating from the frontal triangle. Lateral surface of head with denser rugae forming whorls around the compound eye. Ventral surface of head weakly areolate. Pronotal neck weakly areolate. Pronotum smooth and shining. Anterior half of the katepisternum and lateral portions of the anepisternum smooth and shining, otherwise areolate. Metapleuron areolate. Lateral face of propodeum areolate; propodeal declivity smooth and shining. Median strip of mesoscutum costulate over weak areolate sculpture; smooth and shining laterally. Mesoscutellum smooth and shining medially; lateral faces costulate over weak areolate sculpture. Femora shining through weak areolate sculpture, which becomes stronger distally. Petiole weakly areolate, with the anterior face of the node smooth and shining. Dorsal surface of postpetiole smooth and shining, with posterior quarter shallowly areolate. Gaster smooth and shining, without spectral iridescence.

Setae: antennal scapes and funiculi with short, decumbent pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, erect, blunt-tipped setae, the longest of which are about a third of the width of the compound eye. Finer, blunt setae are present on the ventral surface of the gaster. Short, sparse pubescence present over the entire body, but is difficult to detect against the sculpture.

Color: predominantly testaceous brown; mandibles, antennae, coxae, tarsi, and genitalia yellow.

Smith (1939) - Length 2.2 mm.

Head, exclusive of mandibles, approximately as broad as long, with strongly convex posterior border, and moderately convex sides. Eye extremely large, convex, occupying at least half length of side of head, its anterior border almost touching base of mandible. Clypeus convex. Mandible small, toothed. Postocellar line longer than lateral ocellar line. Antenna slender, 13-segmented, the last 3 segments considerable enlarged. Thorax without Mayrian furrows, but with faint parapsidal furrows. Scutellum strongly gibbous. Epinotum without spines or tubercles. Wings pale, translucent, with very faint veins; discoidal, cubital, and radial cells lacking, but stigma well developed. Legs rather long and slender, femora not incrassate. In profile, peduncle of petiole noticeably short, its dorsal surface forming a gradually ascending slope, which meets the somewhat flattened posterior surface of the node to form a bluntly angular, but low node. Postpetiole from above transversely elliptical, wider than long, but not much wider than petiole. Gaster with basal angles.

Hairs grayish, short, erect, sparse; more abundant on gaster, especially toward apex. Pilosity sparse, appressed; most easily discernible on appendages.

Brown; appendages lighter; apices of coxae, trochanters, bases of femora, and tarsi even lighter.

Type Material

Prebus (2021) - Syntype workers. Texas, U.S.A. One syntype worker here designated lectotype.

Lectotype: U.S.A.: Texas: Travis County: Austin, 15 May 1903, on bark of Salix nigra, Type No. A.M.N.H., M.C.Z. Type 2-1 16371 (MCZENT00016371, middle specimen on pin) Museum of Comparative Zoology.

Paralectotype workers: same pin as lectotype, 2 workers (top and bottom specimens on pin) [MCZC]; same data as lectotype, 3 workers (MCZENT00578574) [MCZC]; [no locality data], [no collection date], W.M. Wheeler, Type No. A.M.N.H., Type 16371, 1 worker (MCZENT00578573) [MCZC].

Etymology

Prebus (2021) - Systematic, from the Latin ‘subditivus’ (= spurious, counterfeit). W.M. Wheeler originally assigned this species to Macromischa with reservations; the species epithet is likely a reflection of his doubts.

References

• Alatorre-Bracamontes, C.E., Vásquez-Bolaños, M. 2010. Lista comentada de las hormigas (Hymenoptera: Formicidae) del norte de México. Dugesiana 17(1):9-36.
• Baroni Urbani, C. 1978b. Materiali per una revisione dei Leptothorax neotropicali appartenenti al sottogenere Macromischa Roger, n. comb. (Hymenoptera: Formicidae). Entomol. Basil. 3:395-618. (page 512, Combination in Leptothorax, and senior synonym of flavitarsis, laevissima and lucilae)
• Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 272, Combination in Temnothorax)
• Creighton, W. S. 1966a ("1965"). The habits and distribution of Macromischa subditiva Wheeler (Hymenoptera: Formicidae). Psyche. 72:282-286. [1966-05-10] (page 282, see also)
• Prebus, M.M. 2021. Taxonomic revision of the Temnothorax salvini clade (Hymenoptera: Formicidae), with a key to the clades of New World Temnothorax. PeerJ. 9:e11514 462p. doi:10.7717/peerj.11514.
• Schumann, R. D. 1993 [1992]. Peculiar appendages in male pupae of Leptothorax subditivus (Wheeler) (Hymenoptera: Formicidae). Psyche. 99:185-188. (page 185, see also)
• Smith, M. R. 1939e. Ants of the genus Macromischa Roger in the United States (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am. 32: 502-509. (page 504, male described)
• Varela-Hernández, F., Medel-Zosayas, B., Martínez-Luque, E.O., Jones, R.W., De la Mora, A. 2020. Biodiversity in central Mexico: Assessment of ants in a convergent region. Southwestern Entomologist 454:673-686.
• Wheeler, W. M. 1903. A revision of the North American ants of the genus Leptothorax Mayr. Proceedings of the Academy of Natural Sciences of Philadelphia. 55:215-260.
• Wheeler, W. M. 1903c. A decade of Texan Formicidae. Psyche. 10:93-111. (page 99, fig. 5 worker described)
• Wheeler, W. M. 1911k. Three new ants from Mexico and Central America. Psyche. 18:203-208.
• Wheeler, W. M. 1931b. New and little-known ants of the genera Macromischa, Creosomyrmex and Antillaemyrmex. Bulletin of the Museum of Comparative Zoology 72:1-34. (page 15, queen described)

References based on Global Ant Biodiversity Informatics

• Baroni Urbani C. 1978. Materiali per una revisione dei Leptothorax neotropicali appartenenti al sottogenere Macromischa Roger, n. comb. (Hymenoptera: Formicidae). Entomol. Basil. 3: 395-618.
• Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
• Castano-Meneses, G., M. Vasquez-Bolanos, J. L. Navarrete-Heredia, G. A. Quiroz-Rocha, and I. Alcala-Martinez. 2015. Avances de Formicidae de Mexico. Universidad Nacional Autonoma de Mexico.
• Creighton W. S. 1966. The habits and distribution of Macromischa subditiva Wheeler (Hymenoptera: Formicidae). Psyche (Cambridge) 72:282-286.
• Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
• Fernández F., E. E. Palacio, W. P. MacKay, and E. S. MacKay. 1996. Introducción al estudio de las hormigas (Hymenoptera: Formicidae) de Colombia. Pp. 349-412 in: Andrade M. G., G. Amat García, and F. Fernández. (eds.) 1996. Insectos de Colombia. Estudios escogidos. Bogotá: Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 541 pp
• Fernández F., and E. E. Palacio. 1995. Hormigas de Colombia IV: nuevos registros de géneros y especies. Caldasia 17: 587-596.
• Gove A. D., J. D. Majer, and V. Rico-Gray. 2005. Methods for conservation outside of formal reserve systems: The case of ants in the seasonally dry tropics of Veracruz, Mexico. Biological Conservation 126: 328-338.
• Gove, A. D., J. D. Majer, and V. Rico-Gray. 2009. Ant assemblages in isolated trees are more sensitive to species loss and replacement than their woodland counterparts. Basic and Applied Ecology 10: 187-195.
• Hess C. G. 1958. The ants of Dallas County, Texas, and their nesting sites; with particular reference to soil texture as an ecological factor. Field and Laboratory 26: 3-72. 
• Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
• LeBrun E. G., R. M. Plowes, and L. E. Gilbert. 2015. Imported fire ants near the edge of their range: disturbance and moisture determine prevalence and impact of an invasive social insect. Journal of Animal Ecology,81: 884–895.
• Maes, J.-M. and W.P. MacKay. 1993. Catalogo de las hormigas (Hymenoptera: Formicidae) de Nicaragua. Revista Nicaraguense de Entomologia 23.
• O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
• Rojas Fernandez P. 2010. Capítulo 24. Hormigas (Insecta: Hymenoptera: Formicidae). In: Diversidad Biológica de Veracruz. Volumen Invertebrados. CONABIO-Gobierno del Estado de Veracruz.
• Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
• Wheeler W. M. 1931. New and little-known ants of the genera Macromischa, Creosomyrmex and Antillaemyrmex. Bulletin of the Museum of Comparative Zoology 72: 1-34.
• Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.