Temnothorax fortispinosus

A likely arboreal nester.

Identification
Prebus (2021) – A member of the salvini group of the Temnothorax salvini clade. Temnothorax fortispinosus can be separated from all other species in the salvini clade by the following character combination: dorsum of mesosoma sinuate and predominantly longitudinally striate; metanotal groove not impressed; propodeum not strongly depressed below the level of the promesonotum; propodeal spines shorter than the propodeal declivity; integument smooth and shining between propodeal spines; subpetiolar tooth small and triangular: 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 1.2 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 dark brown.

Similar species: Fellow members of the salvini group. Temnothorax fortispinosus 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 quetzal, 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 T. quetzal), and smooth integument between the propodeal spines (sculptured in Temnothorax parvidentatus and T. salvini).

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Biology
Prebus (2021) - Temnothorax fortispinosus is only known from several collections from mid elevation forest in the type locality of Custepec, Chiapas State, Mexico. This species, like many of its close relatives in the salvini species group, is probably arboreally nesting.

The closest relative of T. fortispinosus, Temnothorax quetzal, is also only known from its single type locality in the Central American Nucleus, but at a relatively high elevation (1,925 m; Figs. 153C & 153H). These two morphologically distinctive species shared a common ancestor around 8 Ma, and together are sister to the remainder of the salvini group (Prebus, 2021).

Nomenclature

 * . Temnothorax fortispinosus Prebus, 2021: 377, figs. 153C, 156 (w.dq.) MEXICO (Chiapas).

Worker
(n = 5): SL = 0.815-0.881 (0.861); FRS = 0.281-0.296 (0.288); CW = 0.916-0.974 (0.948); CWb = 0.819-0.877 (0.850); PoOC = 0.344-0.377 (0.363); CL = 0.921-0.971 (0.944); EL = 0.212-0.242 (0.229); EW = 0.152-0.183 (0.165); MD = 0.205-0.218 (0.211); WL = 1.204-1.271 (1.245); SPST = 0.301-0.352 (0.323); MPST = 0.346-0.382 (0.361); PEL = 0.435-0.486 (0.465); NOL = 0.247-0.284 (0.266); NOH = 0.167-0.193 (0.177); PEH = 0.300-0.316 (0.309); PPL = 0.225-0.247 (0.234); PW = 0.560-0.612 (0.588); SBPA = 0.243-0.267 (0.257); SPTI = 0.260-0.291 (0.277); PEW = 0.178-0.195 (0.185); PNW = 0.218-0.256 (0.239); PPW = 0.279-0.306 (0.297); HFL = 0.930-0.988 (0.953); HFWmax = 0.176-0.204 (0.190); HFWmin = 0.062-0.070 (0.066); CS = 1.281-1.363 (1.323); ES = 0.294-0.328 (0.312); SI = 99-107 (101); OI = 23-24 (24); CI = 89-91 (90); WLI = 143-152 (147); SBI = 28-32 (30); PSI = 24-28 (26); PWI = 156-167 (161); PLI = 182-215 (199); NI = 136-160 (151); PNWI = 119-139 (129); NLI = 53-61 (57); FI = 279-306 (288).

In full-face view, head subquadrate, longer than broad (CI 89-91). 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 99-107). 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 moderately 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 23-24), 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. Mesosoma sinuate: propodeum slightly depressed below the level of the promesonotum, but dorsal outline is continuous; metanotal groove not impressed. 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 stout and short (PSI 24-28), three quarters as long as the propodeal declivity, flared at the base, straight, and acute. Propodeal declivity flat, forming a rounded ~120° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed. Metapleural gland bulla large, extending from the metacoxal insertion three quarters of the way to the propodeal spiracle. Petiole long (PLI 182-215), without tubercles anterodorsally. Subpetiolar process in the form of a small, triangular, acute tooth, which grades evenly into the ventral margin posteriorly; ventral margin of petiole slightly bulging posterior to it. Petiolar peduncle short: comprising about a third of the total petiole length. Petiolar node rounded-cuneiform: transition between peduncle and node marked by a rounded angle of ~130°; anterior face evenly rounding into the short, strongly convex dorsal face; dorsal face rounding evenly into the posterior face, which forms a ~95° 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 not visible. Metanotal groove not visible. Propodeal spines broadly approximated basally and weakly 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, weakly trapezoidal: slightly broader apically than basally; apical margin weakly convex; node broader than the peduncle and the caudal cylinder. Postpetiole narrow (PWI 156-167) and subquadrate. Anterior margin of postpetiole weakly convex, transitioning into the lateral margins through a rounded angle; lateral margins bulging slightly anteriorly, weakly constricted medially, and weakly diverging posteriorly; posterior margin flat. Metafemur moderately to strongly incrassate (FI 279-306).

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 costate-rugose sculpture overlying the ground sculpture. Lateral surfaces of head sculptured similarly to the dorsum, but sculpture becoming rugose and coarse between the compound eye and the mandibular insertion. Ventral surface of head smooth and shining anteriorly, with areolate-rugulose sculpture posterolaterally. Pronotal neck transversely areolate-costulate. Lateral surfaces of the mesosoma with costae over ground sculpture that is much more weakly areolate than the head; region between the propodeal spiracle and the base of the propodeal spine smooth and shining. Propodeal declivity predominantly smooth and shining, with traces of weak areolae. Dorsal surface of mesosoma sculptured similarly to the lateral surfaces. 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 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 about the length of the compound eye and are directed toward the midline of the body. The head bears ~60, mesosoma ~80, petiole ~14, postpetiole ~22, and first gastral tergite ~84 setae. Pubescence present over the entire body, which is nearly as long as the setae.

Color: predominantly dark brown; mandibles, antennal club, pronotal neck, and tarsi testaceous brown.

Queen
(n = 1): SL = 0.901; FRS = 0.355; CW = 1.121; CWb = 1.037; PoOC = 0.440; CL = 1.077; EL = 0.298; EW = 0.219; MD = 0.205; WL = 1.804; SPST = 0.479; MPST = 0.471; PEL = 0.610; NOL = 0.326; NOH = 0.265; PEH = 0.461; PPL = 0.286; PW = 0.984; SBPA = 0.504; SPTI = 0.487; PEW = 0.261; PNW = 0.357; PPW = 0.442; HFL = 1.057; HFWmax = 0.211; HFWmin = 0.080; CS = 1.576; ES = 0.408; SI = 87; OI = 26; CI = 96; WLI = 174; SBI = 49; PSI = 27; PWI = 169; PLI = 213; NI = 123; PNWI = 137; NLI = 53; FI = 264.

In full-face view, head subquadrate, slightly longer than broad (CI 96). 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 very weakly emarginate medially. Antennal scapes moderately long: when fully retracted, surpassing the posterior margin of the head capsule by about half the maximum width of the scape (SI 87). Antennae 12-segmented; antennal club composed of three segments, with the apical-most segment as long as the preceding two in combination. Frontal carinae short, extending past the antennal toruli by about one and a half 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 20 ommatidia in longest row. Mesoscutum rounded evenly anteriorly, not fully covering the dorsal surface of the pronotum, and weakly convex dorsally. Mesoscutellum convex; anterior margin 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 four spiracle diameters. Propodeal spines well developed, but short (PSI 27), about three quarters as long as the propodeal declivity, flared at the base, directed posteriorly, straight, and acute. Propodeal declivity straight and flat, forming a rounded ~110° 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 213), without tubercles anterodorsally. Subpetiolar process in the form of a tiny, blunt 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 cuneiform-squamiform: transition between peduncle and node an evenly rounded ~120° angle; anterior face forming a rounded ~60° angle with posterior face, which forms a ~110° angle with the caudal cylinder. Postpetiole weakly convex anteriorly, 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 converging slightly apically, their apices separated from each other by about one and a half times their length. Petiolar peduncle with spiracles protruding past the lateral margins. Petiolar node, when viewed posterodorsally, weakly trapezoidal: slightly broader apically than basally; apical margin convex; node broader than the peduncle and the caudal cylinder. Postpetiole narrow (PWI 169) and subquadrate. Anterior margin of postpetiole flat, with corners marked by rounded ~90° angles as it transitions to the lateral margins; lateral margins parallel to each other; posterior margin flat. Metafemur moderately incrassate (FI 264).

Sculpture: median clypeal carina present, extending from the anterior margin to frontal triangle, and flanked by multiple equally strong 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 sculpture becoming rugose near the compound eye, and between the compound eye and mandibular insertion. Ventral surface of sculptured similarly to the dorsum, but weaker. Pronotal neck areolate-strigulate. Lateral surfaces of the mesosoma sculptured similarly to the head, but areolate sculpture much weaker; katepisternum and anepisternum with costae becoming weaker anteriorly. Propodeal declivity strigulate. Mesoscutum and mesoscutellum areolate, with costulate sculpture. Metanotum finely costulate. Propodeum with coarse concentric costae. Femora predominantly smooth and shining, with traces of weak areolate sculpture. Petiole predominantly finely areolate, with fine costulae at the base of the node; sculpture on node is weaker. Anterior face of postpetiole smooth and shining, otherwise finely areolate. First gastral tergite with weak, fine costulae on the basal quarter; otherwise smooth and shining with weak spectral iridescence. 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 about the width of the compound eye. Pubescence present over the entire body, which is nearly as long as the setae.

Color: predominantly dark brown; mandibles, antennal club, pronotal neck, and tarsi testaceous brown.

Type Material
Holotype worker: MEXICO: Chiapas: 2.6 km SE Custepec,, 1,740 m, 18 July 2007, J. Longino #6078, Liquidambar 2nd growth forest, nest in dead stick (JTLC000010282, top specimen on pin).

Paratype gyne and worker: same pin as holotype, 1 dealate gyne (bottom specimen on pin) [CASC]; same data as holotype, 1 worker (JTLC000010283).

Etymology
Morphological, from the Latin ʻfortis' (= robust) + ʻspinosus' (= thorned), in reference to the stout propodeal spines.