Temnothorax laticrus

Temnothorax laticrus is only known from lowland dry forests in Jaragua National Park in the Dominican Republic, where it apparently nests in rotten sticks in the leaf litter or directly in the soil. Little else is known about the biology of this species, but it is probably similar to other members of the terricolous pan-Caribbean pulchellus group.

Identification
Prebus (2021) – A member of the pulchellus group of the Temnothorax salvini clade. There is evidently some color variation between populations: the non-type specimens observed in this study are distinctly bicolored, with the dorsal surface of the head, postpetiole, and gaster dark brown, and the rest of the body testaceous (see worker images figures 143 h-j below in the caste section).

Temnothorax laticrus can be separated from all other species in the salvini clade by the following character combination: anterior margin of the clypeus medially emarginate; metanotal groove not impressed; propodeum not depressed below the level of the promesonotum; propodeum bearing standing setae dorsally; propodeal spines shorter than the propodeal declivity, and directed posterodorsally; hind femora strongly incrassate; in dorsal view, apex of petiolar node laterally compressed, and much narrower than the caudal cylinder of the petiole; petiolar node with more than four erect setae dorsally (usually 12); postpetiole very broad: greater than or equal to 2.3 times the width of the petiole; setae on head, mesosoma, waist segments and gaster erect, moderately long, abundant and blunt (never long and tapering); integument variously colored: either predominantly dark brown, or bicolored, with the antennae, mandibles, mesosoma, legs, and petiole testaceous.

Similar species: It is difficult to imagine that this species would be confused with any other in the genus. Temnothorax laticrus vaguely resembles some of the more densely sculptured members of the pastinifer group, but it is easily separated from them by the short propodeal spines and laterally compressed petiolar node.

Distribution
Low elevations of Hispaniola.

Distribution based on Regional Taxon Lists
Neotropical Region: Dominican Republic.

Nomenclature

 * . Temnothorax laticrus Prebus, 2021: 308, figs. 133I, 143 (w.aq.) DOMINICAN REPUBLIC.

Worker
(n = 7): SL = 0.625-0.690 (0.659); FRS = 0.246-0.273 (0.259); CW = 0.689-0.747 (0.721); CWb = 0.652-0.695 (0.675); PoOC = 0.300-0.319 (0.310); CL = 0.737-0.766 (0.753); EL = 0.147-0.172 (0.157); EW = 0.114-0.128 (0.122); MD = 0.180-0.201 (0.188); WL = 0.886-0.949 (0.917); SPST = 0.154-0.185 (0.171); MPST = 0.266-0.287 (0.278); PEL = 0.377-0.395 (0.386); NOL = 0.227-0.254 (0.242); NOH = 0.127-0.144 (0.133); PEH = 0.233-0.255 (0.249); PPL = 0.179-0.222 (0.206); PPH = 0.249-0.275 (0.261); PW = 0.487-0.517 (0.504); SBPA = 0.149-0.171 (0.159); SPTI = 0.142-0.176 (0.163); PEW = 0.177-0.196 (0.186); PNW = 0.136-0.174 (0.156); PPW = 0.412-0.447 (0.432); HFL = 0.576-0.649 (0.619); HFWmax = 0.217-0.237 (0.226); HFWmin = 0.055-0.060 (0.057); CS = 1.022-1.078 (1.051); ES = 0.204-0.234 (0.218); SI = 94-102 (98); OI = 19-22 (21); CI = 88-91 (90); WLI = 133-138 (136); SBI = 22-25 (23); PSI = 17-20 (19); PWI = 228-243 (233); PLI = 175-217 (188); NI = 165-194 (183); PNWI = 74-92 (84); NLI = 60-66 (63); FI = 369-420 (395).

In full-face view, head subquadrate, longer than broad (CI 88-91). Mandibles weakly striate, 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 entire and flat medially. Antennal scapes moderately long: when fully retracted, extending past the posterior margin of the head capsule by about the maximum width of the scape (SI 94-102). Antennae 12-segmented; antennal club of three 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 moderately protruding past the lateral margins of the head capsule. Lateral margin of head evenly convex, forming a continuous arc from the posterior of the head to the mandibular insertions. Posterior margin of head flat, rounding evenly into the lateral margins.

In profile view, compound eyes ovular, moderately large (OI 19-22), with 12 ommatidia in longest row. Pronotal declivity indistinct, neck and anterior face of pronotum forming a ~120° angle. Pronotum evenly rounded from where it joins the neck to the dorsal margin. Mesosoma flat dorsally for most of its length, but propodeum descends to the base of the propodeal spines, beginning just dorsally to the propodeal spiracle. Promesonotal suture extending from the posterior margin of the procoxal insertion only to the mesothoracic spiracle, which is 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. Propodeal spiracle well developed, directed posterolaterally, and separated from the propodeal declivity by about three spiracle diameters. Propodeal spines poorly developed and small (PSI 17-20), about half the length of the propodeal declivity, tapering evenly from the base, straight, and blunt; represented as blunt teeth on the rounded angle where the dorsal surface of the propodeum meets the propodeal declivity. Propodeal declivity weakly concave, forming a ~110° angle with the base of the propodeal spines. Propodeal lobes weakly developed, with the dorsal margin slightly angulate. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole moderately long (PLI 175-217), without tubercles anterodorsally. Subpetiolar process in the form of a broad triangular tooth, forming a keel posteriorly which grades gradually into the ventral margin of the petiole, so that the process extends along about two thirds of the ventral margin. Petiolar peduncle short: most of the dorsal surface of the petiole composed of the node. Petiolar node robust: transition between peduncle and node evenly rounded, resulting in a slightly concave anterior node face; anterior face forming a ~110° angle with the dorsal face, which is long and weakly convex, nearly flat; dorsal face rounding evenly into the posterior margin, which forms a ~140° angle with the caudal cylinder. Postpetiole evenly rounded anteriorly, flat dorsally, and lobed ventrally.

In dorsal view, humeri moderately developed: evenly rounded and slightly 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 converging evenly to the bases of the propodeal teeth. Propodeal teeth broadly approximated basally and diverging apically, their apices separated from each other by about twice their length; negative space between them an apically truncated "U". Petiole strongly compressed laterally, without spiracles protruding past the lateral margins of the peduncle. Petiolar node roughly ovate: narrowest anteriorly and truncate, rounded posteriorly. Petiolar node slightly wider than the peduncle, and evenly grades into the caudal cylinder, which is slightly wider than the node. Postpetiole very broad (PWI 228-243) and campaniform, articulating with nearly the entire anterior margin of the gaster. Anterior margin of the postpetiole broadly concave, with the corners evenly rounding into the lateral margins, which diverge only slightly to the angulate posterior corners; posterior margin broadly concave. Metafemur strongly incrassate (FI 369-420).

Sculpture: clypeus with multiple (roughly 6) longitudinal carinae medially. Lateral lobes of clypeus with similar, weaker carinae; ground sculpture weakly areolate. Antennal scapes densely areolate, weakly shining. Cephalic dorsum areolate, with areolae arranged into parallel longitudinal rows; rugulae present near the mandibular insertions and on the ventral surface of the head. Mesosoma predominantly areolate, with costulae present on the dorsal and lateral surfaces of the pronotum, as well as the metapleuron. Femora shining through weaker areolate sculpture. Petiole smooth and shining ventrally, with areolate sculpture laterally and dorsally; the dorsal surface of the petiole with weak costulae over the areolate ground sculpture. Dorsal surface of postpetiole with weak costulae anteromedially, which grades into areolate sculpture on the posterior half. Gaster smooth and shining, with strong spectral iridescence. Surface of the first gastral sternite smooth and shining, with weaker spectral iridescence.

Setae: antennal scapes with adpressed pilosity; funiculus with subdecumbent pilosity. Dorsum of head, pronotum, waist segments and gaster with abundant, erect, blunt-tipped setae, the longest of which are about the length of the compound eye. The head bears ~40, mesosoma ~54, petiole 12, postpetiole ~18, and first gastral tergite ~68 setae. Pubescence present on the entire body but more difficult to detect on strongly sculptured surfaces.

Color: head (except for the mandibles and antennal funiculi), mesosoma, legs, and gaster are mostly dark brown. Mandibles, antennal funiculi, trochanters, and tarsi testaceous.

Queen
(n = 1): SL = 0.711; FRS = 0.302; CW = 0.865; CWb = 0.811; PoOC = 0.329; CL = 0.813; EL = 0.221; EW = 0.165; MD = 0.176; WL = 1.306; SPST = 0.276; MPST = 0.328; PEL = 0.460; NOL = 0.256; NOH = 0.174; PEH = 0.344; PPL = 0.192; PPH = 0.327; PW = 0.811; SBPA = 0.354; SPTI = 0.336; PEW = 0.222; PNW = 0.250; PPW = 0.525; HFL = 0.732; HFWmax = 0.194; HFWmin = 0.058; CS = 1.218; ES = 0.304; SI = 88; OI = 25; CI = 100; WLI = 161; SBI = 44; PSI = 21; PWI = 236; PLI = 240; NI = 147; PNWI = 113; NLI = 56; FI = 334.

In full-face view, head subquadrate, roughly as long as broad (CI 100). Mandibles weakly striate, 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. Frontal carinae short, extending past the antennal toruli by one and a half times the maximum width of the antennal scape. Compound eyes moderately protruding past the lateral margins of the head capsule. Antennal scapes very long: when fully retracted, extending past the posterior margin of the head capsule by about two times the maximum scape width (SI 88). Antennae 12-segmented; antennal club of three segments, with the apical-most segment as long as the preceding two in combination. Lateral margin of head slightly convex, converging evenly to the mandibular insertions. Posterior margin of head slightly convex, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and moderately large (OI 25), with 16 ommatidia in longest row. Mesoscutum rounded evenly anteriorly, but just barely covering the dorsal surface of the pronotum, and weakly convex dorsally. Mesoscutellum on the same level as the mesoscutum, not overhanging the metanotum. Propodeal spiracle well developed, directed posterolaterally, and separated from the propodeal declivity by about four spiracle diameters. Propodeal spines poorly developed, but longer than in the worker (PSI 21), about as half as long as the propodeal declivity, tapering evenly from the base, directed posterodorsally, straight, and blunt. Propodeal declivity concave and forming a ~120° angle with the base of the propodeal spines. Propodeal lobes weakly developed, the dorsal margin with a slightly angulate flange. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiolar peduncle moderately long: comprising about half of the petiolar length. Petiolar node cuneiform: transition between peduncle and node evenly rounded, resulting in a concave anterior node face; anterior face forming a very sharp ~80° angle with the dorsal face, which is indistinguishable from the posterior face; together, they form a ~130° angle with the caudal cylinder. Postpetiole subquadrate: weakly convex anteriorly, meeting the dorsal surface at a rounded 90° angle, flattened dorsally, and with a convex ventral surface.

In dorsal view, mesoscutum barely covering pronotum anteriorly, leaving much of the humeri visible laterally. Humeri well developed: the anterior margin broadly convex, meeting the lateral margins at a ~110° angle. Propodeal spines flattened dorsally, broadly approximate basally, and slightly diverging apically, their apices separated from each other by about two and a half times their length. Petiolar peduncle with spiracles slightly protruding past the lateral margins, not noticeably constricted anterior to them. Petiolar node cuneiform, forming a convex transverse ridge anterodorsally; slightly wider than the peduncle, and evenly grading into the caudal cylinder, which is roughly the same width as the node. Postpetiole very broad (PWI 236), anteroposteriorly compressed, and campaniform, articulating with most of the anterior margin of the gaster, leaving small angulate margins on each side exposed. Anterior margin of postpetiole broadly concave, with corners evenly rounding into the lateral margins, which diverge slightly to the angulate posterior corners; posterior margin broadly concave. Metafemur strongly incrassate, but to a lesser extent than the worker (FI 334).

Sculpture: clypeus with multiple (roughly 6) longitudinal carinae medially. Lateral lobes of clypeus with similar, weaker carinae; ground sculpture weakly areolate. Antennal scapes areolate; weakly shining. Cephalic dorsum densely areolate, with costulae; rugulae around the compound eyes and on the ventral surface of the head stronger than in the worker. Lateral sclerites of the mesosoma costulate over areolate ground sculpture, but weaker on the anterior half of the katepisternum. Mesoscutum and mesoscutellum with strong costulae with weaker cross-reticulations; mesoscutum with a small patch of smooth sculpture anteromedially. Femora shining through weak areolate sculpture. Petiole smooth and shining ventrally; dorsal surface of peduncle and anterior surface of node with weak rugae over weak areolate ground sculpture; dorsal surface of node rugose. Dorsal surface of postpetiole dull with costulae anteriorly, grading into areolate sculpture posteriorly. Gaster smooth and shining, with extensive spectral iridescence on all visible sclerites.

Setae: antennal scapes with adpressed pilosity; funiculus with subdecumbent pilosity. Dorsum of head, pronotum, waist segments and gaster with abundant, erect, blunt-tipped setae, the longest of which are about two-thirds the width of the compound eye. Pubescence present on the entire body but more difficult to detect on strongly sculptured surfaces.

Color: head (except for the mandibles and antennal funiculi), mesosoma, legs, and gaster are mostly dark brown. Mandibles, antennal funiculi, wing bases, trochanters, and tarsi testaceous.

Type Material
Holotype worker: DOMINICAN REPUBLIC: Pedernales: Jaragua National Park, ± 16 m, 125 m, 26 March 2012, D. Lubertazzi #DL03387, xeric scrub on limestone, half buried branch (3.5 cm diameter) and in soil (CASENT0758263).

Paratype workers and gyne: same data as holotype, 1 worker (CASENT0733974) 1 worker (CASENT4010181)  1 worker (CASENT4010182)  1 worker (CASENT4010183)  1 alate gyne (MCZENT00510556) [MCZC]; same data as holotype, except: #DL03388, xeric scrub on limestone, sifted soil and litter under half buried branch, 1 worker (CASENT4010184)  1 worker (MCZENT00510558) [MCZC].

Etymology
Morphological, from the Latin ʻlatus' (= broad) + ʻcrus' (= leg), in reference to the notably incrassate femora in the worker of this species.