Temnothorax parvidentatus

A likely arboreal nester.

Identification
Prebus (2021) - Temnothorax parvidentatus can be separated from all other species in the salvini clade by the following character combination: smaller species: WL less than 1.18 mm; dorsum of mesosoma weakly convex and irregularly rugose; metanotal groove not impressed; propodeum not strongly depressed below the level of the promesonotum; propodeal spines about as long as the propodeal declivity; integument sculptured between propodeal spines; subpetiolar tooth small and spiniform: shorter than the setae that arise from the peduncle directly above; petiolar node weakly squamiform: in dorsal view, petiolar node more than or equal to 1.4 times as broad as caudal cylinder, but less than or equal to 1.5 times as broad; setae on head, mesosoma, legs, waist segments and gaster erect to suberect, moderately long, abundant and tapering; integument bicolored: antennae, base of mandibles, head capsule (excluding clypeus), propodeal spine tips, legs (excluding tarsi beyond first tarsomere), waist segments, first gastral tergite and sternite, and the distal half of the remaining gastral sclerites testaceous brown; clypeus, mesosoma, tarsi (excluding first tarsomere), and basal halves of the gastral sclerites (excluding the first gastral tergite and sternite) testaceous yellow.

Similar species: Fellow members of the salvini group. Temnothorax parvidentatus can be separated from other members of the salvini group by the weakly squamiform petiolar node (petiolar node more than or equal to 1.6 times as broad as the caudal cylinder in Temnothorax aztecus, Temnothorax aztecoides, Temnothorax longicaulis and Temnothorax paraztecus, but less than 1.3 times in Temnothorax salvini), relatively small subpetiolar tooth (longer than the setae that arises directly above it in Temnothorax longinoi), short propodeal spines (longer than the propodeal declivity in Temnothorax quetzal), and sculptured integument between the propodeal spines (smooth and shining in Temnothorax fortispinosus).

Distribution based on Regional Taxon Lists
Neotropical Region: Guatemala.

Biology
Temnothorax parvidentatus is known from a few collections in mid elevation cloud forests in Guatemala; additional specimens were collected from the orchid Odontoglossum grande in quarantine. Apparently restricted to the Central American Nucleus, this species is sister to the geographically widespread group consisting of Temnothorax aztecus, Temnothorax longicaulis, Temnothorax longinoi, Temnothorax paraztecus, and Temnothorax salvini, with which it shared a common ancestor a little more than 9 Ma (Prebus, 2020). Temnothorax parvidentatus has been found in dead twigs, live hollow stems, and by beating vegetation. Like many of its close relatives in the salvini species group, this species apparently nests and forages arboreally.

Nomenclature

 * . Temnothorax parvidentatus Prebus, 2021: 401, figs. 153G, 161 (w.q.) GUATEMALA.

Worker
(n = 6): SL = 0.730-0.821 (0.794); FRS = 0.225-0.282 (0.259); CW = 0.756-0.906 (0.858); CWb = 0.672-0.807 (0.760); PoOC = 0.311-0.341 (0.330); CL = 0.779-0.892 (0.860); EL = 0.179-0.230 (0.211); EW = 0.131-0.167 (0.153); MD = 0.205-0.256 (0.225); WL = 1.001-1.18 (1.132); SPST = 0.269-0.363 (0.327); MPST = 0.300-0.365 (0.334); PEL = 0.368-0.499 (0.433); NOL = 0.213-0.252 (0.232); NOH = 0.120-0.167 (0.153); PEH = 0.230-0.295 (0.268); PPL = 0.199-0.251 (0.228); PW = 0.466-0.572 (0.538); SBPA = 0.200-0.263 (0.238); SPTI = 0.225-0.303 (0.269); PEW = 0.142-0.186 (0.166); PNW = 0.210-0.280 (0.243); PPW = 0.229-0.308 (0.279); HFL = 0.804-0.931 (0.889); HFWmax = 0.151-0.180 (0.170); HFWmin = 0.060-0.076 (0.066); CS = 1.062-1.253 (1.19); ES = 0.245-0.313 (0.287); SI = 97-109 (105); OI = 23-26 (24); CI = 86-90 (88); WLI = 146-151 (149); SBI = 30-33 (31); PSI = 27-31 (29); PWI = 161-178 (168); PLI = 177-221 (190); NI = 138-178 (153); PNWI = 141-151 (146); NLI = 47-58 (54); FI = 237-283 (260).

In full-face view, head subquadrate, longer than broad (CI 86-90). 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 weakly emarginate medially. Antennal scapes very long: when fully retracted, surpassing the posterior margin of the head capsule by about three times the maximum width of the antennal scape (SI 97-109). Antennae 12-segmented; antennal club of composed of three segments, with the apical-most segment slightly longer 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 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 23-26), with 17 ommatidia in longest row. Pronotal declivity indistinct, neck and anterior face of pronotum forming a ~100° angle. Anterior face of pronotum evenly rounding into dorsal face. Dorsum of mesosoma very weakly convex, nearly flat from where it joins the anterior face of the pronotum to the propodeal spines. 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 moderately well developed, directed posterolaterally, and separated from the propodeal declivity by about five spiracle diameters. Propodeal spines moderately well developed and moderately long (PSI 27-31), as long as the propodeal declivity, tapering evenly from the base, acute, straight, and directed posterodorsally. Propodeal declivity weakly concave, forming a rounded ~120° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed, but dorsal margin slightly angulate. Metapleural gland bulla moderately large, extending from the metacoxal insertion two thirds of the way to the propodeal spiracle. Petiole moderately long (PLI 177-221), without tubercles anterodorsally. Subpetiolar process in the form of a small, spiniform, acute, anteriorly curved tooth; ventral margin of petiole weakly concave posterior to it but bulging slightly medially. Petiolar peduncle moderately long: comprising about half the total petiole length. Petiolar node rounded-squamiform: transition between peduncle and node marked by a rounded angle of ~130°; anterior face rounding evenly into the posterior face, the dorsal margin evenly convex; posterior face forms a ~110° 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 slightly wider than the rest of the mesosoma; mesothoracic spiracles protruding past the lateral margins of the mesosoma, visible as angles where the pronotum meets the mesonotum. Promesonotal suture visible as a slight disruption in the ground sculpture and a dark transverse band. Metanotal groove absent. Propodeal spines broadly approximated basally and slightly 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 weakly convex; node broader than the peduncle and the caudal cylinder. Postpetiole narrow (PWI 161-178) and subquadrate. Anterior margin of the postpetiole weakly convex, evenly rounding into the lateral margins, which bulge slightly anteriorly, and weakly converge posteriorly; posterior margin flat. Metafemur weakly to moderately incrassate (FI 237-283).

Sculpture: median clypeal carina present, extending posteriorly to the frontal triangle, and flanked on either side by two equally strong carinae. Lateral clypeal lobes with additional, weaker carinae; ground sculpture shining but very weakly areolate. Antennal scapes areolate-costulate. Cephalic dorsum densely rugose over areolate sculpture, becoming costate between the frontal carinae; fine concentric costulae surrounding the antennal insertions. Lateral surfaces of head sculptured similarly to the dorsum. Ventral surface of head shining through weak areolate sculpture over the gular region, otherwise with weak costulae over weak areolate ground sculpture. Pronotal neck areolate. Lateral surfaces of the mesosoma sculptured similarly to the head, but propodeum with costulae over smooth ground sculpture, and weak areolate sculpture between the propodeal spiracle and the base of the propodeal spine. Propodeal declivity weakly strigulate. Dorsal surface of mesosoma sculptured similarly to the cephalic dorsum and the lateral mesosoma surface. Femora shining through weak areolate sculpture. Petiole shining and weakly areolate on all surfaces but the ventral surface of the peduncle, which is smooth and shining; areolae becoming even weaker on the node. Postpetiole smooth and shining dorsally, but with weak areolate sculpture on the posterior quarter and on the lateral faces. First gastral tergite smooth and shining, with weak spectral iridescence. First gastral sternite smooth and shining, with very weak spectral iridescence.

Setae: antennal scapes and funiculi with long, suberect pilosity. Dorsum of the head, pronotum, waist segments, and gaster with abundant, erect, tapering, flexuous setae, the longest of which are about one and a quarter times the length of the compound eye and are directed toward the midline of the body. The head bears&gt;80, mesosoma ~68, petiole ~18, postpetiole ~24, and first gastral tergite&gt;80 setae. Pubescence present over the entire body, which is nearly as long as the setae.

Color: bicolored. antennae, base of mandibles, head capsule (excluding clypeus), propodeal spine tips, legs (excluding tarsi beyond first tarsomere), waist segments, first gastral tergite and sternite, and the distal half of the remaining gastral sclerites testaceous brown. Clypeus, mesosoma, tarsi (excluding first tarsomere), and basal halves of the gastral sclerites (excluding the first gastral tergite and sternite) testaceous yellow.

Queen
(n = 1): SL = 0.828; FRS = 0.307; CW = 0.976; CWb = 0.873; PoOC = 0.348; CL = 0.923; EL = 0.258; EW = 0.175; MD = 0.231; WL = 1.652; SPST = 0.407; MPST = 0.408; PEL = 0.595; NOL = 0.283; NOH = 0.201; PEH = 0.374; PPL = 0.270; PW = 0.950; SBPA = 0.442; SPTI = 0.412; PEW = 0.248; PNW = 0.363; PPW = 0.394; HFL = 1.033; HFWmax = 0.177; HFWmin = 0.069; CS = 1.335; ES = 0.346; SI = 95; OI = 26; CI = 95; WLI = 189; SBI = 51; PSI = 25; PWI = 159; PLI = 220; NI = 141; PNWI = 146; NLI = 48; FI = 257.

In full-face view, head subquadrate, longer than broad (CI 95). 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 emarginated medially. Antennal scapes very long: when fully retracted, surpassing the posterior margin of the head capsule by about two and a half times the maximum width of the scape (SI 95). Antennae 12-segmented; antennal club composed of three segments, with the apical-most segment about as long as the preceding two in combination. Frontal carinae long, extending past the antennal toruli by about three 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 26), with 21 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 level as the mesoscutum; dorsum sloping downward posteriorly. Posterior margin of metanotum extending past the posterior margin of the mesoscutellum. Propodeal spiracle moderately well developed, directed posterolaterally, and separated from the propodeal declivity by about four spiracle diameters. Propodeal spines stout, well developed, and moderately long (PSI 25), about as long as the propodeal declivity, tapering evenly from the base, directed posterodorsally, straight, and acute. Propodeal declivity weakly concave, 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 moderately large, extending from the metacoxal insertion two thirds of the way to the propodeal spiracle. Petiole long (PLI 220), without tubercles anterodorsally. Subpetiolar process in the form of an acute, spiniform tooth, which grades evenly into the ventral margin of the petiole posteriorly. Petiolar peduncle moderately long: comprising about half of the total petiole length. Petiolar node rounded-squamiform: transition between peduncle and node a rounded ~150° angle; anterior face rounding evenly into the posterior face, which forms a ~120° 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 two times their length. Petiolar peduncle with spiracles weakly protruding past the lateral margins. Petiolar node, when viewed posterodorsally, roughly trapezoidal: slightly broader apically than basally; apical margin convex; node broader than the peduncle and the caudal cylinder. Postpetiole narrow (PWI 159) and subquadrate. Anterior margin of postpetiole weakly convex, with corners rounding evenly into the lateral margins; lateral margins parallel to each other; posterior margin flat. Metafemur moderately incrassate (FI 257).

Sculpture: median clypeal carina present, extending from the anterior margin to frontal triangle, and flanked on either side by two slightly weaker carinae. Lateral clypeal lobes with additional weaker carinae; ground sculpture weakly areolate. Antennal scapes weakly areolate-costulate. Cephalic dorsum densely rugose over areolate ground sculpture, becoming costate between the frontal carinae. Lateral surfaces of head sculptured similarly to the dorsum, but with rugae stronger between the compound eye and the mandibular insertion. Ventral surface of head weakly costulate, becoming strigulate posteriorly. Pronotal neck areolate. Anterior face of pronotum shining and weakly sculptured; humeri rugose; lateral faces coarsely costate over weak areolate ground sculpture. Katepisternum predominantly shining, with weak costulae on the posterior third. Anepisternum finely, weakly costulate over areolate ground sculpture. Metapleuron and lateral surface of propodeum costate. Propodeal declivity strigulate. Mesoscutum and mesoscutellum areolate, with costulate sculpture; mesoscutum with a small patch of weak areolate sculpture anteromedially. Metanotum finely areolate. Propodeum coarsely rugose. Femora predominantly smooth and shining. Petiole finely longitudinally areolate-costulate on nearly all surfaces, but smooth and shining on the ventral surface of the petiole; sculpture weaker on the dorsum of the node. Postpetiole predominantly shining through weak areolate sculpture; areolae becoming stronger on the posterior quarter and on the lateral faces. First gastral tergite smooth and shining, with weak spectral iridescence. First gastral sternite weakly areolate basally, otherwise smooth and shining, with weak spectral iridescence.

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

Color: bicolored. Antennae, base of mandibles, head capsule (excluding median lobe of clypeus), wing bases, propodeal spine tips, legs (excluding tarsi beyond first tarsomere), waist segments, first gastral tergite and sternite, and the distal half of the remaining gastral sclerites testaceous brown. Median lobe of clypeus, mesosoma, tarsi (excluding first tarsomere), and basal halves of the gastral sclerites (excluding the first gastral tergite and sternite) testaceous yellow.

Type Material
Holotype worker: GUATEMALA: Suchitepéquez: 4 km S Volcán Atitlán, ± 20 m, 1,570 m, 16 June 2009, J. Longino #JTL6717, cloud forest, ex dead twig (CASENT0756087).

Paratype workers and gynes: same data as holotype, 1 alate gyne (CASENT0612665) [CASC] 1 worker (CASENT0612667) ; same data as holotype, except: ± 300 m, 1,580 m, 15 June 2009, J. Longino #JTL6715, cloud forest, ex live stem, 1 worker (CASENT0758698)  1 worker (CASENT0758786)  1 dealate gyne (CASENT0612659) [USNM] 1 worker (CASENT0612660)  1 worker (CASENT0612661)  1 worker (CASENT0612662)  1 worker (CASENT0612663) [MCZC] 1 worker (CASENT0612664).

Etymology
Morphological, from the Latin ʻparvus' (= small) + ʻdentatus' (= toothed), in reference to the relatively small subpetiolar tooth.