Temnothorax skwarrae

The types were collected from in an epiphyte (Tillandsia streptophylla).

Identification
Prebus (2021) – A member of the fuscatus group of the Temnothorax salvini clade. Temnothorax skwarrae can be separated from all other species in the salvini clade by the following character combination: antennal scapes short: failing to reach the posterior margin of the head by about the maximum width of the antennal scape (SI 92); body elongate (WLI >150); metanotal groove not strongly impressed; propodeal spines directed posterodorsally, never directly upward; propodeal spines short, much shorter than the length of the propodeal declivity (PSI 18); hind femora strongly incrassate (FI >350); petiolar node low, elongate and rounded dorsally (NI 244); postpetiole narrow: greater than one and a half times as wide as the petiole in dorsal view, but less than 2 times as wide (PWI 198); setae on head, mesosoma, waist segments and gaster erect, moderately long, moderately dense and blunt (never long and tapering); integument bicolored: dark brown with a yellow gaster.

Similar species: Temnothorax acutispinosus, Temnothorax subditivus, Temnothorax tenuisculptus, Temnothorax tuxtlanus, species of the annexus, augusti, fuscatus, and salvini groups. Temnothorax skwarrae can be distinguished from T. tuxtlanus by the incrassate femora (FI < 280 in T. tuxtlanus). The low, elongate petiolar node (NI >180) will separate T. skwarrae from all species listed above, aside from the salvini group and most other members of the fuscatus group. The moderately long, blunt-tipped setae will separate T. skwarrae from the species of the salvini group, which have long, tapering setae. The short propodeal spines, which are much shorter than the propodeal declivity, as well as the bicolored integument, will distinguish T. skwarrae from Temnothorax fuscatus and Temnothorax nebliselva, which have longer propodeal spines and are uniformly colored. Temnothorax skwarrae can be separated from Temnothorax ocarinae by the relatively large, oval compound eye, which is about as long as the distance between the compound eye and the mandibular insertion (shorter than the distance between the compound eye and mandibular insertion in T. ocarinae). Furthermore, T. skwarrae has a bright yellow gaster, as opposed to medium brown in T. ocarinae.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Biology
The type series of Temnothorax skwarrae was collected from a Tillandsia circinnata epiphyte found near Cuernavaca in Morelos state, Mexico. Very little is known about the biology of this species, but it resembles Temnothorax ocarinae from Jalisco state, and the cloud forest species Temnothorax fuscatus, which has a range in Central America from south of the Isthmus Tehuantepec to Costa Rica. This species, like T. fuscatus, is apparently arboreally nesting. Temnothorax skwarrae has also been reported from tropical dry forest habitat in Estacion de Biologia Chamela in Jalisco state (Dáttilo et al., 2020) but the species determination needs to be confirmed.

Nomenclature

 *  skwarrae. Macromischa skwarrae Wheeler, W.M. 1931b: 10 (w.q.) MEXICO. Combination in Leptothorax: Baroni Urbani, 1978b: 503; in Temnothorax: Bolton, 2003: 272.

Worker
Length 1.4-1.7 mm.

Differing from the preceding forms of stolli in its smaller average size, less swollen femora, in having the petiole as broad as long and in lacking erect hairs on the body. The body is very smooth and shining, yellow throughout, except for a brown subapical ring on the middle and hind tibiae, a brown terminal joint to the antennal club and a spot of the same color on each side of the first to third gastric segments. The fourth segment is indistinctly brownish throughout.

Prebus (2021) - (n = 1): SL = 0.737; FRS = 0.247; CW = 0.857; CWb = 0.804; PoOC = 0.387; CL = 0.965; EL = 0.219; EW = 0.174; MD = 0.218; WL = 1.270; SPST = 0.231; MPST = 0.368; PEL = 0.388; NOL = 0.342; NOH = 0.140; PEH = 0.248; PPL = 0.264; PPH = 0.291; PW = 0.558; SBPA = 0.164; SPTI = 0.189; PEW = 0.177; PNW = 0.145; PPW = 0.350; HFL = 0.880; HFWmax = 0.255; HFWmin = 0.069; CS = 1.287; ES = 0.306; SI = 92; OI = 24; CI = 83; WLI = 158; SBI = 20; PSI = 18; PWI = 198; PLI = 147; NI = 244; PNWI = 82; NLI = 88; FI = 370.

In full-face view, head subquadrate, longer than broad (CI 83). Mandibles densely 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 weakly emarginate medially. Antennal scapes short: when fully retracted, failing to reach the posterior margin of the head capsule by about the width of the antennal scape (SI 92). 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 very weakly concave but rounding evenly into the lateral margins.

In profile view, compound eyes ovular and moderately large (OI 24), with 14 ommatidia in longest row. Pronotal declivity distinct, neck and anterior face of pronotum forming a rounded ~90° angle; transition between the anterior and dorsal faces delimited by a transverse carina. Dorsal face of pronotum evenly rounding into the rest of the mesosoma, which is flat 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 four spiracle diameters. Propodeal spines weakly developed and short (PSI 18), about a third as long as the propodeal declivity, tapering evenly from the base, weakly downcurved, and acute. Propodeal declivity weakly concave, forming a rounded ~120° angle with the base of the propodeal spines. Propodeal lobes dorsally angulate and small. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole moderately long (PLI 147), with tubercles anterodorsally. Subpetiolar process in the form of a very small, blunt tooth; ventral margin of petiole flat posterior to it. Petiolar peduncle short: comprising about a quarter of the total length of the petiole. Petiolar node low and dorsally rounded transition between peduncle and node an even grade, resulting in a weakly concave anterior node face; anterior face meeting the dorsal face at a rounded ~120° angle; dorsal face rounding evenly into the posterior face. Postpetiole long; anterior and dorsal faces forming an even convexity; lobed ventrally.

In dorsal view, humeri developed and distinct: evenly 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 weakly diverging apically, their apices separated from each other by about their length, the negative space between them broadly "U" shaped. Petiolar peduncle with spiracles not protruding past the lateral margins. Petiolar node ovular, slightly longitudinally elongate, and narrowed anteriorly; node the same width as the peduncle and the caudal cylinder. Postpetiole narrow (PWI 198) and campaniform. Anterior margin of the postpetiole convex and evenly rounds into the lateral margins, which are parallel to each other; posterior corners angulate; posterior margin weakly emarginate medially. Metafemur strongly incrassate (FI 370).

Sculpture: median clypeal carina present, extending posteriorly nearly to the frontal triangle, and flanked on either side by two equally strong carinae. Lateral clypeal lobes with additional, weaker carinae; ground sculpture areolate. Antennal scapes areolate. Cephalic dorsum densely areolate, with overlying reticulate sculpture; cross-reticulations weaker between the frontal carinae. Lateral surfaces of head densely areolate, with dense reticulate sculpture overlying the ground sculpture. Ventral surface of head longitudinally coarsely areolate-costulate. Pronotal neck areolate. Lateral surface of the mesosoma densely, finely areolate, with coarse longitudinal striae overlying the ground sculpture. Propodeal declivity weakly transversely areolate-costulate. Dorsal surface of mesosoma densely areolate, with coarse rugose sculpture overlying the ground sculpture on the pronotum and propodeum; mesonotal area without overlying sculpture. Femora areolate. Petiole densely areolate, with a coarse longitudinal carina extending from the anterodorsal flange to the caudal cylinder; reticulate sculpture overlying the areolate ground sculpture dorsal to the carina. Postpetiole densely areolate, with reticulate sculpture overlying the ground sculpture. First gastral sternite uniformly weakly areolate, with weak spectral iridescence. First gastral sternite 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 sparse, erect, blunt-tipped setae, the longest of which are about the length of the compound eye. The head bears ~34, mesosoma ~30, petiole 8, postpetiole ~16, and first gastral tergite ~30 setae. Short, sparse pubescence present over the entire body, but difficult to detect against the densely sculptured integument.

Color: bicolored. Predominantly dark brown, with a testaceous yellow gaster. Mandibles and legs testaceous brown.

Queen
Length 3.5-3.7 mm.

Decidedly smaller than the females of floridanus and rufescens, with less swollen and more compressed femora, shorter petiole and much less abundant pilosity. Yellow like the worker, with the ocellar triangle, mandibular teeth, wing-insertions and metanotum blackish, the brown spots on the sides of the first to third segments large and conspicuous and the fourth with a broad transverse brown band. The spots on the second and third segments are really the lateral portions of medially interrupted bands. Terminal joint of antennal club fuscous; femora scarcely infuscated. Wings colorless, with yellow veins and pterostigma.

Male
Length 1.3-1.5 mm.

Head distinctly broader than long, somewhat broader behind than in front, with nearly straight posterior border, rounded sides and dorsal surface. Anteriorly placed eyes convex, nearly half as long as the sides of the head. Clypeus convex, with bidenticulate anterior border. Mandibles small, narrow, quadridenticulate. Antennal scape as long as the first and second funicular joints together, first funicular small and globular; joints 2 to 6 slightly longer than broad, the last four decidedly longer, the terminal joint somewhat thicker than the penultimate and twice as long.

Thorax stout anteriorly, narrowed posteriorly to the small epinotum, which is convex and rounded, without distinct base and declivity; mesosterna very convex. Petiole slightly longer than broad, with a low, rounded node above. Postpetiole and gaster shaped much as in the worker.

Shining; head more subopaque, finely striate-punctate. Pilosity sparse, delicate, whitish, short and suberect, as abundant on the legs as on the dorsum of the body. Black or deep piceous brown; appendages and mandibles pale whitish yellow; femora infuscated; wings colorless as in the female, with pale brownish pterostigma.

Type Material
Described from two males, three mature female pupae and several workers taken by Dr. Elisabeth Swarra in an epiphyte, Tillandsia streptophylla Scheidw., at Mirador, in the State of Veracruz, Mexico.

Prebus (2021) - Syntype workers and gyne. Cuernavaca, Mexico. One syntype worker here designated lectotype.

Lectotype worker: MEXICO: Morelos: Cuernavaca, 26 June 1929, E. Skwarra #Z857a/ Sk. 1 worker (M.C.Z. co-type 10 16358, MCZENT00016358).

Paralectotype workers and gyne: same data as previous, except: E. Skwarra #Z879/ Sk., ex Tillandsia circinnata, 1 dealate gyne (M.C.Z. co-type 916358, MCZENT00577117) [MCZC]; same data as previous, except: E. Skwarra #Z877, ex Tillandsia circinnata, 1 worker (images of FoCol 0411 examined on antweb.org) 1 teneral worker (images of FoCol 0412 examined on antweb.org) [SMNG]; same data as previous, except: E. Skwarra #Z807a/ Sk., ex Tillandsia circinnata (images of M.C.Z. cotype 4-5 16358, S.N.M.G. type no. co 59607, USNMENT00532047 examined on the Smithsonian National Museum of Natural History Department of Entomology Collections website).

Etymology
Prebus (2021) - Matronym, named for Elizabeth Skwarra, who collected the type series.

References based on Global Ant Biodiversity Informatics

 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133