Temnothorax aztecus ( Wheeler, 1931 )

Prebus, Matthew M., 2021, Taxonomic revision of the Temnothorax salvini clade (Hymenoptera: Formicidae), with a key to the clades of New World Temnothorax, PeerJ (e 11514) 9, pp. 1-462 : 368-376

Temnothorax aztecus ( Wheeler, 1931)

Distribution: Fig. 153B ; worker, gyne & male: Fig. 155 .

Macromischa azteca Wheeler, 1931: 8 . Syntype workers, gyne, and males: Mirador, Mexico. One syntype worker here designated lectotype.

Macromischa azteca maya Wheeler, 1937: 458 . Syntype workers and gynes. Mocá , Guatemala. Junior synonym of Temnothorax aztecus by Baroni Urbani, 1978: 425.

One syntype worker here designated lectotype.

Leptothorax aztecus (Wheeler) : Baroni Urbani, 1978: 425. First combination in Leptothorax .

Temnothorax aztecus (Wheeler) : Bolton, 2003: 271. First combination in Temnothorax .

Type material examined: Lectotype worker of Macromischa azteca : MEXICO: Veracruz: Mirador , 10 May 1929, E. Skwarra #Z435/ Sk, top specimen on pin (images of M.C.Z. Type 16357 examined on the MCZ Type Database website) [ MCZC].

Paralectotype workers of Macromischa azteca : same pin as lectotype (M.C.Z. Type 16357, remaining workers on pin) [ MCZC] ; same data as previous: 3 workers (LACMENT323181) [ LACM] ; same data as previous, except: E. Skwarra #Z420/ Sk., 3 workers (LACMENT181967) [ LACM] .

Lectotype worker of Macromischa azteca maya : GUATEMALA: Sololá: Mocá : 22 March 1935, W.M. Wheeler (images of M.C. Z. co-type 22801 examined on the M.C.Z. Type Database website).

Paralectotype workers of Macromischa azteca maya : 3 workers (syntypes of Macromischa azteca maya, LACMENT 181956) [ LACM].

Non-type material examined: BELIZE: Cayo: Chiquibul National Park, Doyle’ s Delight , Dry Creek Trail , 16.483333 ° N 89.050000 ° W, 950–1,100 m, 20–22 August 2007, P. Kovarik #2007-09, yellow pan trap, 1 worker (CASENT0614827) [ UCDC] .

GUATEMALA: Izabal: 16 km ESE Morales : 15.41109 ° N 88.71184 ° W ± 108 m, 440 m, 19 May 2009, LLAMA#Go-B-04-3-01, 2 ° lowland rainforest, beating vegetation, 1 worker (CASENT0613028) [ JTLC]; 15.40780 ° N 88.69698 ° W ± 210 m, 530 m, 19 May 2009, LLAMA#Go-B-04-3-04, 2 ° lowland rainforest, beating vegetation, 1 worker (CASENT0758692) [ UCDC]; 15.41109 ° N 88.71184 ° W ± 58 m, 440 m, 19 May 2009, LLAMA#Ba-B-04-3-02-07, 2 ° lowland rainforest, at bait, 1 worker (CASENT0610593) [ JTLC]; 15.41186 ° N 88.71071 ° W ± 28 m, 410 m, 19 May 2009, LLAMA#Wm-B-04-2-04, 2 ° lowland rainforest, ex sifted leaf litter, 1 worker (CASENT0611481) [ JTLC] .

HONDURAS: Atlántida: 10 km SSW Tela , 15.69843 ° N 87.47256 ° W ± 20 m, 550 m, 17 June 2010, LLAMA#Wm-C-08-2-03, tropical wet forest, ex sifted leaf litter, 1 worker (CASENT0618641) [ JLTC]; 15.69479 ° N 87.47707 ° W ± 20 m, 720 m, 17 June 2010, LLAMA#Wm-C-08-1-10, tropical wet forest, ex sifted leaf litter, 1 worker (CASENT0618595) [ JTLC]; 12 km SW La Ceiba, 15.69134 ° N 86.86137 ° W ± 20 m, 280 m, 19 June 2010, LLAMA#Wa-C-09-2-40, tropical rainforest, ex sifted leaf litter, 1 worker (CASENT0624888) [ JTLC] . Comayagua: Parque National Cerro Azul Meambar : 14.86991 ° N 87.89879 ° W ± 20 m, 1,120 m, 20 May 2010, LLAMA#Wa-C-04-1-46, 1 worker (CASENT0615293) [ JTLC]; 14.86979 ° N 87.89874 ° W ± 20 m, 1,120 m, 20 May 2010, LLAMA#Wa-C-04-1-49, 1 worker (CASENT0758693) [ UCDC]; same data as previous, except: 14.886993 ° N 87.90479 ° W ± 110 m, 770 m, 21 May 2010, LLAMA#Wm-C-04-2-01, montane rainforest, ex sifted leaf litter, 1 worker (CASENT0617422) [ JTLC] .

MEXICO: Chiapas: Lago Metzabok : 17.12562 ° N 91.63086 ° W ± 300 m, 570 m, 6 June 2008, LLAMA#Go-A-06-1-03, lowland wet forest, beating vegetation, 1 worker (CASENT0609815) [ JTLC] ; 17.12366 ° N 91.63716 ° W, 575 m, 5 June 2008, LLAMA Wa-A- 06-2-18, lowland wet forest, ex sifted leaf litter, 1 dealate gyne ( JTLC000014408 ) [ JTLC] ; 17.12365 ° N 91.63748 ° W, 575 m, 5 June 2008, LLAMA Wa-A-06-2-25, lowland wet forest, ex sifted leaf litter, 1 dealate gyne ( JTLC000014413 ) [ JTLC] ; 17.12380 ° N 91.63635 ° W, ± 100 m, 575 m, 8 June 2008, D.J. Cox #0142, 1 worker (CASENT0609754) [ JTLC] 1 worker (CASENT0609755) [ JTLC] 1 worker (CASENT0758793) [ JTLC] 1 worker (CASENT0758691) [ UCDC] 1 male (CASENT0609756) [ JTLC] . Oaxaca: Uluapan, 4 km NE Ayautla , 18.05906 ° N 96.64564 ° W ± 250 m, 400 m, 10 June 2016, ADMAC#Go-F- 03-1-03, lowland rainforest, beating vegetation, 1 worker (CASENT0640555) [ JTLC] ; Veracruz: Los Tuxtlas : 26 July 1974, R.L. Jeanne, forest, on understory vegetation, 1 worker (LACMENT323179) [ LACM]; 23 July 1974, R.L. Jeanne, forest, on understory vegetation, 1 worker (LACMENT323180) [ LACM] 1 worker (CASENT0759976) [ FSCA]; 1 km SW Los Tuxtlas Biological Station , 18.57863 ° N 95.08113 ° W ± 40 m, 450 m ± 10 m, 16 August 2014, M.M. Prebus #MMP01643, lowland tropical rainforest, beating vegetation, 1 worker (CASENT0733469) [ MMPC] ; 18.58090 ° N 95.08085 ° W ± 20 m, 410 m ± 5 m, 16 August 2014, M.M. Prebus #MMP01648, lowland tropical rain forest, nest in small twig, 42 workers (CASENT0732975) [ MMPC]; 0.5 km SW Los Tuxtlas Biological Station , 18.58272 ° N 95.07763 ° W ± 20 m, 280 m ± 5 m 16 August 2014, M.M. Prebus #MMP01650, lowland tropical rainforest, beating vegetation, 1 worker (CASENT0733501) [ MMPC] .

NICARAGUA: Matagalpa: Reserva Natural Cerro Musún : 12.96392 ° N 85.23242 ° W ± 100 m, 900 m, 3 May 2011, LLAMA#Go-D-01-1-03, montane wet forest, beating vegetation, 1 worker (CASENT0627684) [ JTLC] 1 worker (CASENT0627794) [ JTLC]; 12.95949 ° N 85.22562 ° W ± 100 m, 650 m, 3 May 2011, LLAMA#Go-D-01-2-03, tropical wet forest, beating vegetation, 1 worker (CASENT0627800) [ JTLC] 1 worker (CASENT0732561) [ UCDC] 1 worker (CASENT0627802) [ JTLC] 1 worker (CASENT0627801) [ JTLC] 1 dealate gyne (CASENT0627698) [ JTLC]; RAAN: PN Cerro Saslaya, 13.77361 ° N 84.98650 ° W ± 20 m, 510 m, 8 May 2011, LLAMA#Wm-D-02-1-05, tropical wet forest, ex sifted leaf litter, 1 worker (CASENT0628778) [ JTLC] .

Geographic range: Low-to-mid elevations of southern Mexico to Nicaragua ( Fig. 153B ).

Worker diagnosis: Temnothorax aztecus can be separated from all other species in the salvini clade by the following character combination: smaller species: WL <1.17 mm; dorsum of mesosoma weakly sinuate; metanotal groove not impressed; propodeum not strongly depressed below the level of the promesonotum; propodeal spines present and longer than the propodeal declivity; subpetiolar tooth acutely spiniform and longer than the setae that arise from the peduncle directly above; petiolar node strongly squamiform: in dorsal view, petiolar node greater than or equal to 1.6 times as broad as caudal cylinder; dorsum of head predominantly costate-rugose over areolate ground sculpture; dorsum of petiolar node, postpetiole and entire first gastral tergite smooth and shining; setae on head, mesosoma, legs, waist segments and gaster erect to suberect, long, abundant and tapering; integument predominantly yellow.

Similar species: Fellow members of the salvini group. Temnothorax aztecus can be separated from other members of the salvini group by the strongly squamiform petiolar node (petiolar node less than or equal to 1.5 times as broad as the caudal cylinder in T. longinoi sp. nov., T. quetzal sp. nov., T. fortispinosus sp. nov., T. parvidentatus sp. nov., and T. salvini ), yellow integument ( T. longinoi sp. nov., T. longicaulis stat. nov., nom. nov., T. quetzal sp. nov., T. fortispinosus sp. nov., T. parvidentatus sp. nov., and T. salvini are variously colored, but never uniformly yellow), smooth dorsum of the petiolar node, postpetiole, and gaster (lightly sculptured in T. aztecoides sp. nov.), relatively large subpetiolar tooth (shorter than the setae that arises directly above it in T. aztecoides sp. nov.), and long propodeal spines (shorter than the propodeal declivity in T. paraztecus sp. nov.).

Worker measurements & indices (n = 20): SL = 0.706 –0.798 (0.745); FRS = 0.219 –0.262 (0.247); CW = 0.741 –0.838 (0.802); CWb = 0.642 –0.738 (0.701); PoOC = 0.278 –0.328 (0.300); CL = 0.742 –0.831 (0.799); EL = 0.167 –0.225 (0.201); EW = 0.132 –0.161 (0.144); MD = 0.188 –0.220 (0.205); WL = 1.024 –1.168 (1.104); SPST = 0.359 –0.479 (0.404); MPST = 0.288 –0.352 (0.323); PEL = 0.397 –0.464 (0.439); NOL = 0.217 –0.282 (0.245); NOH = 0.138 –0.181 (0.155); PEH = 0.248 –0.293 (0.264); PPL = 0.188 –0.247 (0.210); PW = 0.492 –0.548 (0.523); SBPA = 0.189 –0.243 (0.225); SPTI = 0.255 –0.334 (0.295); PEW = 0.140 –0.172 (0.159); PNW = 0.258 –0.309 (0.281); PPW = 0.225 –0.275 (0.254); HFL = 0.756 –0.897 (0.823); HFWmax = 0.177 –0.202 (0.191); HFWmin = 0.047 –0.071 (0.061); CS = 1.013–1.15 (1.101); ES = 0.233 –0.303 (0.273); SI = 103–111 (106); OI = 23–27 (25); CI = 85–90 (88); WLI = 152–163 (157); SBI = 28–36 (32); PSI = 32–42 (37); PWI = 150–168 (159); PLI = 182–226 (209); NI = 120–177 (159); PNWI = 161–199 (177); NLI = 49–62 (56); FI = 273–379 (316).

Worker description: In full-face view, head subquadrate, longer than broad (CI 85–90). Mandibles 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 flat medially. Antennal scapes moderately long: when fully retracted, surpassing the posterior margin of the head capsule by about the maximum width of the antennal scape (SI 103–111). Antennae 12-segmented; antennal club of composed of three segments, with the apical-most segment as long as the preceding two in combination. Frontal carinae moderately long, extending past the antennal toruli by about two times the maximum width of the antennal scape. Compound eyes strongly protruding past the lateral margins of the head capsule. Lateral margin of head weakly convex, forming a continuous arc from the mandibular insertions to the posterior margin of the head. Posterior head margin flat but rounding evenly into the lateral margins.

In profile view, compound eyes ovular and moderately large (OI 23–27), with 17 ommatidia in longest row. Pronotal declivity indistinct, neck and anterior face of pronotum forming a ~120 ° angle. Anterior face of pronotum evenly rounding into dorsal face. Promesonotum very weakly convex to the faint metanotal groove. Propodeum weakly convex. Promesonotal suture extending from the posterior margin of the procoxal insertion only to the mesothoracic spiracle, which is moderately well 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 well developed, directed posterolaterally, and separated from the propodeal declivity by about four spiracle diameters. Propodeal spines well developed and very long (PSI 32–42), slightly longer than the propodeal declivity, tapering evenly from the base, straight, and acute. Propodeal declivity weakly concave, forming a rounded ~120 ° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed. Metapleural gland bulla moderately large, extending from the metacoxal insertion two thirds of the way to the propodeal spiracle. Petiole long (PLI 182–226), without tubercles anterodorsally. Subpetiolar process in the form of a moderately large, spiniform, acute tooth; ventral margin of petiole weakly concave posterior to it. Petiolar peduncle very long: comprising about two thirds of the total petiole length. Petiolar node squamiform: transition between peduncle and node marked by a rounded angle of ~120 °; anterior face forming a ~90 ° angle with the very short, strongly convex dorsal face; dorsal face rounding evenly into the posterior face, which forms a ~90 ° angle with the caudal cylinder. Postpetiole evenly rounded anterodorsally, bulging before flattening posterodorsally; concave ventrally.

In dorsal view, humeri developed and distinct: evenly rounded and about one and a half times 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. Promesonotal suture visible as a darker band and disruption in the ground sculpture. Metanotal groove moderately well impressed. Propodeal spines broadly approximated basally and diverging apically, their apices separated from each other by about their length, the negative space between them “U” shaped. Petiolar peduncle with spiracles slightly protruding past the lateral margins, but not noticeably constricted anterior to them. Petiolar node, when viewed posterodorsally, trapezoidal: broader apically than basally; apical margin flat; node broader than the peduncle and the caudal cylinder. Postpetiole narrow (PWI 150–168) and campaniform. Anterior margin of the postpetiole convex, evenly rounding into the lateral margins, which diverge to the angulate posterior corners; posterior margin flat. Metafemur moderately to strongly incrassate (FI 273–379).

Sculpture: median clypeal carina present, extending posteriorly to the frontal triangle, and flanked on either side by multiple slightly weaker carinae. Lateral clypeal lobes with additional, weaker carinae; ground sculpture weakly areolate. Antennal scapes weakly areolate. Cephalic dorsum areolate, with predominantly costate-rugose sculpture overlying the ground sculpture; fine concentric costulae surrounding the antennal insertions. Lateral surfaces of head sculptured similarly to the dorsum, but rugae forming whorls around the compound eyes and rugose sculpture coarser between the compound eye and the mandibular insertion. Ventral surface of head smooth and shining, with weak costulae. Pronotal neck areolate. Lateral surfaces of the mesosoma sculptured similarly to the head, with costulae. Propodeal declivity strigulate. Dorsal surface of mesosoma areolate, with costate-rugose sculpture on the pronotum and strigulae on the propodeum. Femora shining through weak areolate sculpture. Petiole finely areolate on all surfaces but the node, which is smooth and shining. Postpetiole smooth and shining dorsally, weakly areolate laterally. First gastral tergite and sternite smooth and shining, without spectral iridescence.

Setae: antennal scapes and funiculi with moderately long, suberect pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, suberect, tapering, flexuous setae, the longest of which are slightly longer than the length of the compound eye and are directed toward the midline of the body. The head bears ~40, mesosoma ~42, petiole 4, postpetiole ~18, and first gastral tergite ~84 setae. Pubescence present over the entire body, which is nearly as long as the setae.

Color: predominantly yellow; masticatory margin of the mandible dark brown; tibiae and distal quarter of femora testaceous yellow.

Gyne measurements & indices (n = 2): SL = 0.756 –0.757 (0.757); FRS = 0.293 –0.311 (0.302); CW = 0.912 –0.923 (0.918); CWb = 0.803 –0.814 (0.809); PoOC = 0.332 –0.348 (0.340); CL = 0.859 –0.915 (0.887); EL = 0.247 –0.250 (0.249); EW = 0.182 –0.184 (0.183); MD = 0.205 –0.237 (0.221); WL = 1.556 –1.609 (1.583); SPST = 0.386 –0.431 (0.409); MPST = 0.419 –0.426 (0.423); PEL = 0.579 –0.589 (0.584); NOL = 0.338 –0.344 (0.341); NOH = 0.185 –0.202 (0.194); PEH = 0.349 –0.364 (0.357); PPL = 0.267 –0.269 (0.268); PW = 0.857 –0.864 (0.861); SBPA = 0.412 –0.440 (0.426); SPTI = 0.383 –0.419 (0.401); PEW = 0.225 –0.239 (0.232); PNW = 0.315 –0.388 (0.352); PPW = 0.376 –0.394 (0.385); HFL = 0.913 –0.947 (0.930); HFWmax = 0.188 –0.191 (0.190); HFWmin = 0.064 –0.071 (0.068); CS = 1.233 –1.272 (1.252); ES = 0.338 –0.342 (0.340); SI = 93–94 (94); OI = 27–28 (27); CI = 89–93 (91); WLI = 194–198 (196); SBI = 51–55 (53); PSI = 25–27 (26); PWI = 157–175 (166); PLI = 215–221 (218); NI = 167–186 (177); PNWI = 140–162 (151); NLI = 58–58 (58); FI = 265–298 (282).

Gyne description: In full-face view, head subquadrate, longer than broad (CI 89–93). Mandibles finely striate but shining and armed with five teeth: the apical-most well developed, followed by a less developed preapical tooth and three equally developed smaller teeth. Anterior clypeal margin flat medially. Antennal scapes moderately long: when fully retracted, surpassing the posterior margin of the head capsule by about the maximum width of the scape (SI 93–94). Antennae 12-segmented; antennal club composed of three segments, with the apical-most segment slightly shorter than the preceding two in combination. Frontal carinae moderately long, extending past the antennal toruli by about two times the maximum width of the antennal scape. Compound eyes strongly protruding past the lateral margins of the head capsule. Lateral margin of head evenly convex, converging from below the compound eyes to the mandibular insertions. Posterior head margin flat, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and large (OI 27–28), with 17 ommatidia in longest row. Mesoscutum rounded evenly anteriorly, not fully covering the dorsal surface of the pronotum, and weakly convex dorsally. Anterior margin of mesoscutellum on the same plane as the mesoscutum but sloping posteriorly. Posterior margin of metanotum extending past the posterior margin of the mesoscutum. Propodeal spiracle very well developed, directed posterolaterally, and separated from the propodeal declivity by about five spiracle diameters. Propodeal spines stout and well developed, but short (PSI 25–27), about two thirds as long as the propodeal declivity, tapering evenly from the base, directed posteriorly, straight, and acute. Propodeal declivity straight and flat, forming a rounded ~120 ° angle with the base of the propodeal spines. Propodeal lobes rounded and very weakly developed, but slightly angulate dorsally. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole long (PLI 215–221), without tubercles anterodorsally. Subpetiolar process in the form of moderately long, spiniform, very acute tooth, which grades evenly into the ventral margin of the petiole posteriorly. Petiolar peduncle moderately long: comprising half of the total petiole length. Petiolar node squamiform: transition between peduncle and node an evenly rounded ~120 ° angle; anterior face forming a rounded ~110 ° angle with the dorsal face, which is short; dorsal face rounding evenly into the posterior face, which forms a ~110 ° angle with the caudal cylinder. Postpetiole evenly rounded anterodorsally, bulging before flattening posterodorsally; concave ventrally.

In dorsal view, mesoscutum not fully covering pronotum anteriorly; humeri visible laterally as rounded sclerites. Mesoscutum evenly rounded anteriorly; anterior margin rounding evenly into the lateral margins; lateral margins diverging to the wing bases, then converging through a curve to the convex posterior margin. Propodeal spines strongly diverging basally, but parallel to each other apically, their apices separated from each other by about one and a half times their length. Petiolar peduncle with spiracles weakly protruding past the lateral margins. Petiolar node, when viewed posterodorsally, roughly trapezoidal: broader apically than basally; apical margin convex; node broader than the peduncle and the caudal cylinder. Postpetiole narrow (PWI 157–175) and subquadrate. Anterior margin of postpetiole flat, with corners marked by rounded angles as it transitions to the lateral margins; lateral margins parallel to each other; posterior margin flat. Metafemur moderately incrassate (FI 265–298).

Sculpture: median clypeal carina present, extending from the anterior margin to frontal triangle, and flanked by multiple slightly weaker carinae. Lateral clypeal lobes with additional weaker carinae; ground sculpture weakly areolate. Antennal scapes weakly areolate. Cephalic dorsum areolate, with costate-rugose sculpture overlying the ground sculpture; fine concentric costulae surrounding the antennal insertions. Lateral surfaces of head sculptured similarly to the dorsum, but rugae forming whorls posterior to the compound eyes. Ventral surface of head smooth and shining, with weak costulae. Pronotal neck areolate. Lateral surfaces of the mesosoma sculptured similarly to the head, with costae over areolate sculpture; anepisternum with a small patch of smooth and shining sculpture anteriorly. Propodeal declivity strigulate. Mesoscutum and mesoscutellum areolate, with costulae and weak strigulae on the propodeum. Dorsum of propodeum coarsely rugose. Femora predominantly smooth and shining; basal quarter weakly areolate. Petiole finely longitudinally areolate-costulate on all surfaces, but sculpture on node is weaker. Postpetiole predominantly smooth and shining, with weak areolate sculpture laterally and on the posterior quarter. First gastral tergite with weak, fine costulae on the basal quarter; otherwise smooth and shining with weak spectral iridescence. First gastral sternite smooth and shining, without spectral iridescence.

Setae: antennal scapes and funiculi with moderately long, suberect pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, suberect, tapering, flexuous setae, the longest of which are slightly longer than the width of the compound eye. Pubescence present over the entire body, which is nearly as long as the setae.

Color: predominantly yellow; masticatory margin of the mandible, wing bases, and distal quarters of the gastral sclerites dark brown; tibiae and distal quarter of femora testaceous yellow. Tips of the propodeal spines and dorsum of waist segments testaceous.

Male measurements & indices (n = 1): SL = 0.186; FRS = 0.109; CW = 0.600; CWb = 0.473; PoOC = 0.206; CL = 0.514; EL = 0.246; EW = 0.179; MD = 0.056; WL = 0.951; SPST = n/a; MPST = 0.255; PEL = 0.334; NOL = 0.205; NOH = 0.06; PEH = 0.15; PPL = 0.157; PW = 0.587; SBPA = n/a; SPTI = n/a; PEW = 0.144; PNW = 0.138; PPW = 0.224; HFL = 0.858; HFWmax = 0.095; HFWmin = 0.048; CS = 0.73; ES = 0.336; SI = 39; OI = 46; CI = 92; WLI = 201; SBI = n/a; PSI = n/a; PWI = 156; PLI = 213; NI = 342; PNWI = 96; NLI = 61; FI = 198.

Male description: In full-face view, head subovate, slightly longer than broad (CI 92). Mandibles very weakly striate, shining, and armed with five teeth: the apical-most well developed, followed by a smaller preapical tooth and three roughly equally developed smaller teeth. Anterior clypeal margin entire and weakly convex. Antennal scapes short: when fully retracted, failing to reach the posterior margin of the head capsule by about five times the maximum width of the antennal scape (SI 39). Antennae 13-segmented; antennal club composed of four segments, with the apical-most segment slightly longer than the preceding two in combination. Frontal carinae short, extending past the antennal toruli by about the maximum width of the antennal scape. Compound eyes strongly protruding past the lateral margins of the head capsule. Lateral margin of head convex, margin between the anterior margin of the compound eye and the mandibular insertions straight. Posterior head margin evenly convex, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and large (OI 46), with 24 ommatidia in the longest row. Mesoscutum bulging anteriorly, but not fully covering the dorsal surface of the pronotum, convex dorsally. Mesoscutellum depressed slightly below the level of the mesoscutum, convex dorsally. Posterior margin of metanotum extending beyond the posterior margin of the mesoscutellum. Propodeum strongly depressed; flat dorsally and meeting the propodeal declivity at a distinct ~100 ° angle. Propodeal spiracle moderately well developed, directed posterolaterally, and separated from the propodeal declivity by about three spiracle diameters. Propodeal spines absent. Propodeal lobes rounded and weakly developed. Metapleural gland bulla small, extending a quarter of the way between the insertion of the metacoxa and the propodeal spiracle. Petiole moderately long (PLI 218), without tubercles anterodorsally. Subpetiolar process a small, acute, triangular tooth; ventral margin of petiole bulging slightly posterior to it. Petiolar peduncle moderately long: comprising about half of the total petiole length. Petiolar node low and rounded, nearly cuneiform; the convergence of the anterior and dorsal faces marked by a rounded ~100 ° angle. Postpetiole evenly rounded anterodorsally, flattened dorsally, and concave ventrally.

In dorsal view, mesoscutum not fully covering pronotum anteriorly; humeri visible laterally as slivers of rounded sclerites. Petiolar peduncle with spiracles slightly protruding past the lateral margins. Petiolar node slightly wider than the peduncle and the caudal cylinder; trapezoidal when view at a posterodorsal aspect, the apex flat and broader than the base. Postpetiole narrow (PWI 156) and campaniform. Anterior margin of postpetiole flat, with the anterior corners evenly rounding into the lateral margins, which evenly diverge to the angulate posterior corners; posterior margin of postpetiole flat. Metafemur not incrassate (FI 198).

Sculpture: median clypeal lobe with three equally strong carinae. Antennal scapes shining, with traces of weak areolate sculpture. Dorsum of head areolate, with rugulae between the compound eye and antennal insertion. Lateral surface of head areolate, with rugulae surrounding the compound eye. Ventral surface of head shining, with weak costulae. Pronotal neck areolate. Anterior face of pronotum smooth and shining. Lateral surface of pronotum predominantly smooth and shining, with a posteromedial patch of finely areolate and costulate sculpture, and weak areolate sculpture near the dorsal and ventral margins. Katepisternum weakly areolate, with smooth and shining patches near the dorsal and ventral margins. Anepisternum smooth and shining. Metapleuron predominantly smooth and shining, with a small patch of weak areolate sculpture over the metapleural gland bulla. Lateral face of the propodeum weakly rugulose. Propodeal declivity weakly areolate. Dorsally, mesoscutum weakly areolate, with smooth and shining patches abutting the Mayrian furrows laterally. Mesoscutellum predominantly smooth and shining, with traces of weak costulate sculpture. Femora smooth and shining, with traces weak areolate sculpture. Petiole predominantly weakly areolate, but node smooth and shining. Dorsal surface of postpetiole shining, with traces of weak areolate sculpture laterally and on the posterior quarter. First gastral tergite and sternite smooth and shining, without spectral iridescence.

Setae: antennal scapes and funiculi with moderately long, suberect pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, suberect, tapering, flexuous setae, the longest of which are as long as the width of the compound eye. Pubescence present over the entire body, which is nearly as long as the setae.

Color: Predominantly testaceous brown, with yellow antennae, mouthparts, legs, and genitalia.

Etymology: Geographical, in reference to the type series locality in the former Aztec empire.

Comments: Temnothorax aztecus nests arboreally in hollow twigs and vines in the mid to low elevation tropical wet forests of Mesoamerica, from the Isthmus of Tehuantepec to the Nicaraguan depression. This species has also been collected in Winkler leaf litter extractions, suggesting that there may be some flexibility in nesting preference. Foragers are frequently collected on low vegetation. Temnothorax aztecus is not particularly closely related to T. aztecoides sp. nov. (having shared a common ancestor approximately 10 Ma ( Prebus, 2021)), but the two species are very similar in appearance and have overlapping geographical ranges, especially in the Los Tuxtlas mountain complex (and probably the southern Sierra Madre) in Mexico ( Figs. 153A & 153B ). Temnothorax aztecus appears to inhabit lower elevations (<1,200 m), while T. aztecoides sp. nov. inhabits higher elevations (> 1,000 m) ( Figs. 153A & 153B ). The closest relative of T. aztecus is the morphologically similar T. paraztecus sp. nov., with which it shared a common ancestor a little more than 7 Ma ( Prebus, 2021). Temnothorax aztecus and T. paraztecus sp. nov. also overlap geographically in the Central American Nucleus, but T. paraztecus sp. nov., similar to T. aztecoides sp. nov. inhabits a generally higher elevational range (> 950 m) than T. aztecus ( Figs. 153B & 153F ) Inhabiting a large present-day geographical range, T. aztecus is the only member of the salvini species group that is found below 900 m ( Fig. 153B ). Following speciation from the lineage leading to T. paraztecus , the T. aztecus lineage was inferred to have expanded into lower elevation habitats during the Miocene-Pliocene transition around 7.5 Ma ( Prebus, 2021).

Figures

Figure 153 Geographical and elevational distribution of the salvini group. (A) Temnothorax aztecoides sp. nov. (B) T. aztecus (C) T. fortispinosus sp. nov. (D) T. longicaulis stat. nov., nom. nov. (E) T. longinoi sp. nov. (F) T. paraztecus sp. nov. (G) T. parvidentatus sp. nov. (H) T. quetzal sp. nov. (I) T. salvini (J) T. terraztecus sp. nov. Colored scale to the left of each map represents elevation in meters. Points in black represent the species named in each subfigure, while points in red represent other members of the species group. Type localities are represented by triangles; if present, types of synonyms are named; non-type localities are represented by circles. Bounding box in inset map shows location of main map. Full-size DOI: 10.7717/peerj.11514/fig-153

Figure 155 Temnothorax aztecus. (A–C) Worker (CASENT0758793). (A) Full-face view. (B) Profile view. (C) Dorsal view. (D–F) Gyne (JTLC000014408). (D) Full-face view. (E) Profile view. (F) Dorsal view. (G–J) Male (CASENT0609756). (G) Full-face view. (H) Profile view. (I) Dorsal view. (J) Wings. Scale bars 0.2 mm. Full-size DOI: 10.7717/peerj.11514/fig-155