Temnothorax casanovai, Prebus, 2021

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 : 142-148

Temnothorax casanovai sp. nov.

Distribution, worker & gyne: Fig. 106 .

Type material examined: Holotype worker: MEXICO: Puebla: San Rafael Coxcatlán, 1,250 m 18.350000 ° N 97.116667 ° W, April 2000, L. Rios Casanova, pitfall trap ZIII T7, ( LACMENT323462 ) [ LACM].

Paratype workers: MEXICO: Puebla: same data as holotype, 1 worker (LACMENT323463) [ LACM]; same data as previous, except: July 2000, pitfall trap UII T16, 1 worker (LACMENT323460) [ MCZC] 1 worker (LACMENT323461) [ CASC] .

Non-type material examined: MEXICO: Puebla: Zapotitlán de las Salinas, Jardín Botánico , 23 August 2003, L. Rios Casanova, LRC#2003-17, deteriorated terrace, in branch of Pitahaya, 1 alate gyne, 2 workers (LACMENT323464) [ LACM] 3 workers (LACMENT323465) [ LACM] .

Geographic range: Mid elevations of south-central Mexico (Puebla) ( Fig. 106G ).

Worker diagnosis: The following character combination separates Temnothorax casanovai sp. nov. from all other species in the salvini clade: very long antennal scapes, which surpass the posterior margin of the head by about two times the maximum width of the scape (SI 108–121); mesosoma about one and a half times as long as the width of the head (WLI 151–161); propodeal spines short, about half as long as the propodeal declivity (PSI 28–32); metapleural gland bulla small, extending from the metacoxal insertion a third way to the propodeal spiracle; petiolar peduncle long, with the peduncle comprising a little more than half the length of the petiole; petiolar node subquadrate and erect, not overhanging the caudal cylinder of the petiole; postpetiole narrow to moderately broad, about two times the width of the petiole in dorsal view (PWI 181–203); first gastral tergite strongly areolate and dull, with abundant suberect setae; erect setae on the dorsal surface of the head; bicolored integument, testaceous with brown appendages and gaster.

Similar species: Temnothorax subditivus , T. tenuisculptus , and species of the annexus and augusti groups. Temnothorax casanovai sp. nov. can be separated from T. augusti and T. aureus sp. nov. by the petiolar node, which leans posteriorly in T. augusti and T. aureus sp. nov., overhanging the caudal cylinder. Furthermore, the first gastral tergite is weakly sculptured in T. augusti and is smaller than T. casanovai sp. nov.: WL <0.9 mm. Temnothorax casanovai sp. nov. can be separated from T. leucacanthus , T. leucacanthoides sp. nov., and T. aureus sp. nov. by their longer propodeal spines, which are about the length of the propodeal declivity (PSI> 35) and their larger metapleural gland bullae, which extend from the metacoxal insertion more than halfway to the propodeal spiracle. The antennal scapes of T. leucacanthus and T. leucacanthoides sp. nov. are shorter than T. casanovai sp. nov., failing to surpass the posterior margin of the head (SI <110), and also have smooth first gastral tergites. Temnothorax casanovai sp. nov. differs from T. tenuisculptus by the propodeal spines, which are about the length of the propodeal declivity in T. tenuisculptus , and are directed upward, forming a higher angle with the propodeal declivity; additionally, T. tenuisculptus has a shorter petiolar peduncle, comprising about a third of the total petiole length, and a depressed propodeum. Temnothorax casanovai sp. nov. can be separated from T. subditivus by the petiolar node in dorsal view, which is much broader than the peduncle in T. subditivus , as well as the first gastral tergite, which is smooth and shining in T. subditivus . Temnothorax casanovai sp. nov. can be separated from species in the annexus group by the pedunculate petiole, which always comprises less than half the total petiole length in the annexus group.

Worker measurements & indices (n = 9): SL = 0.668 –0.830 (0.778); FRS = 0.199 –0.248 (0.221); CW = 0.677 –0.807 (0.737); CWb = 0.619 –0.752 (0.677); PoOC = 0.317 –0.390 (0.350); CL = 0.776 –0.933 (0.855); EL = 0.168 –0.197 (0.183); EW = 0.133 –0.150 (0.140); MD = 0.178 –0.230 (0.205); WL = 0.947 –1.199 (1.053); SPST = 0.263 –0.341 (0.311); MPST = 0.295 –0.373 (0.335); PEL = 0.337 –0.483 (0.408); NOL = 0.197 –0.264 (0.238); NOH = 0.141 –0.184 (0.158); PEH = 0.239 –0.308 (0.270); PPL = 0.143 –0.230 (0.180); PPH = 0.179 –0.274 (0.222); PW = 0.439 –0.559 (0.492); SBPA = 0.158 –0.233 (0.183); SPTI = 0.180 –0.293 (0.238); PEW = 0.138 –0.192 (0.160); PNW = 0.199 –0.281 (0.233); PPW = 0.269 –0.362 (0.306); HFL = 0.761 –0.944 (0.868); HFWmax = 0.176 –0.218 (0.204); HFWmin = 0.053 –0.065 (0.06); CS = 1.007 –1.219 (1.104); ES = 0.236 –0.270 (0.252); SI = 108–121 (115); OI = 22–24 (23); CI = 76–81 (79); WLI = 151–161 (156); SBI = 26–31 (27); PSI = 28–32 (30); PWI = 181–203 (191); PLI = 203–258 (229); NI = 132–186 (151); PNWI = 135–154 (145); NLI = 53–65 (58); FI = 317–363 (338).

Worker description: In full-face view, head subquadrate, elongate (CI 76–81). Mandibles densely, finely striate but weakly 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 emarginate medially. Antennal scapes very long: when fully retracted, surpassing the posterior margin of the head capsule by about two times the maximum width of the scape (SI 108–121). 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 short, extending past the antennal toruli by about one and a half 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 evenly convex, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and moderately large (OI 22–24), with 17 ommatidia in longest row. Pronotal declivity indistinct, but neck and anterior face of pronotum forming a ~120 ° angle; anterior face evenly rounding into the dorsal face. Mesosoma evenly, but weakly convex from where it joins the pronotal neck to the base of 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 weakly developed, directed posterolaterally, and separated from the propodeal declivity by about five spiracle diameters. Propodeal spines moderately well developed, but short (PSI 28–32), two thirds the length of the propodeal declivity, tapering evenly from the base, straight, and blunt. Propodeal declivity flat, forming a rounded ~100 ° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed. Metapleural gland bulla small, extending from the metacoxal insertion a third way to the propodeal spiracle. Petiole long (PLI 203–258), without tubercles anterodorsally. Subpetiolar process in the form of small triangular tooth, ventral margin of petiole flat. Petiolar peduncle long: comprising a little more than half the length of the petiole. Petiolar node robust and erect, subquadrate: transition between peduncle and node marked by a rounded angle of ~120 °, resulting in a concave anterior node face; anterior face meeting the dorsal face at a ~90 ° angle; dorsal face weakly convex, nearly flat, meeting the posterior face at a rounded angle of ~90 °; posterior face forming a ~90 ° angle with the caudal cylinder. Postpetiole subquadrate and antero-posteriorly compressed, anterior face flat, bulging slightly anterodorsally before transitioning into the flattened posterodorsal face; weakly lobed ventrally.

In dorsal view, dorsal margin of pronotum weakly delimited from the pronotal declivity by a very weak carina. Humeri developed: evenly rounded and wider than the rest of the mesosoma; mesothoracic spiracles very weakly protruding past the lateral margins of the mesosoma, visible as slight angles where the pronotum meets the mesonotum. Promesonotal suture barely visible as a slight disruption in the ground sculpture. 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, their bases joined by a rounded transverse welt, diverging weakly 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; peduncle weakly constricted anterior to them. Petiolar node weakly campaniform: weakly convex posteriorly, more strongly convex anteriorly; node broader than the peduncle, and about one and half times as wide as the caudal cylinder. Postpetiole subquadrate and narrow to moderately broad (PWI 181–203), articulating with most of the anterior margin of the gaster, leaving small, angulate margins on each side exposed. Anterior margin of the postpetiole flat, evenly rounding into the lateral margins, which diverge very slightly to the angulate posterior corners; posterior margin broadly concave. Metafemur strongly incrassate (FI 317–363).

Sculpture: clypeus with eight parallel longitudinal carinae. Lateral clypeal lobes with additional, weaker carinae; ground sculpture areolate. Antennal scapes areolate. Cephalic dorsum areolate, but with very fine costulae overlying the ground sculpture; fine concentric costulae surrounding the antennal insertions. Lateral surfaces of head sculptured similarly to the dorsum of the head, but with rugulae becoming stronger and forming cross reticulations between the compound eye and mandibular insertions. Ventral surface of head shining through weak areolate-costulate sculpture. Mesosoma with areolate sculpture on the pronotal neck. Lateral surface of the mesosoma strongly areolate, with costulate sculpture on the pronotum the border of the meso- and metapleurae. Propodeal declivity weakly areolate. Dorsal surface of mesosoma areolate, with costulae overlying the ground sculpture. Femora areolate. Petiole and postpetiole predominantly weakly areolate, but sculpture is weaker on the ventral surface of the petiolar peduncle. First gastral tergite strongly areolate and dull, with spectral iridescence. First gastral sternite smooth and shining, with spectral iridescence.

Setae: antennal scapes and funiculi with short, decumbent pilosity. Dorsum of the head, pronotum, waist segments, and gaster with moderately abundant, erect, blunt-tipped, nearly clavate setae, the longest of which are about half the width of the compound eye. The head bears ~32, mesosoma ~48, petiole 10, postpetiole ~20, and first gastral tergite ~94 setae. Short, sparse pubescence present over the entire body, but difficult to detect against the ground sculpture and light integument.

Color: predominantly testaceous, with antennae, protibiae and protarsi, mid legs, hind legs, and gaster medium brown.

Gyne measurements & indices (n = 1): SL = 0.806; FRS = 0.263; CW = 0.869; CWb = 0.788; PoOC = 0.355; CL = 0.897; EL = 0.244; EW = 0.187; MD = 0.200; WL = 1.406; SPST = 0.324; MPST = 0.391; PEL = 0.464; NOL = 0.274; NOH = 0.209; PEH = 0.375; PPL = 0.212; PPH = 0.312; PW = 0.939; SBPA = 0.382; SPTI = 0.414; PEW = 0.221; PNW = 0.297; PPW = 0.422; HFL = 0.939; HFWmax = 0.204; HFWmin = 0.064; CS = 1.237; ES = 0.338; SI = 102; OI = 27; CI = 88; WLI = 178; SBI = 48; PSI = 23; PWI = 191; PLI = 219; NI = 131; PNWI = 134; NLI = 59; FI = 319.

Gyne description: In full-face view, head subquadrate, longer than broad (CI 88). Mandibles densely, finely striate but weakly 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 emarginate medially. Antennal scapes very long: when fully retracted, surpassing the posterior margin of the head capsule by about one and a half times the maximum width of the antennal scape (SI 102). Antennae 12-segmented; antennal club 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 moderately protruding past the lateral margins of the head capsule. Lateral margin of head weakly convex, diverging from the mandibular insertions to below the compound eyes. Posterior margin of head convex, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and large (OI 27), with 20 ommatidia in longest row. Mesoscutum rounded evenly anteriorly, covering the dorsal surface of the pronotum, and flat dorsally. Mesoscutellum on the same level as the mesoscutum. Posterior margin of metanotum extending slightly past the posterior margin of the mesoscutum. Propodeal spiracle moderately well developed, directed posterolaterally, and separated from the propodeal declivity by about five spiracle diameters. Propodeal spines stout and moderately well developed, but short (PSI 23), about half as long as the propodeal declivity, tapering evenly from the base, directed posteriorly, straight, and blunt. Propodeal declivity straight and flat, forming a rounded ~100 ° 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 219), without tubercles anterodorsally. Subpetiolar process in the form of a very small, triangular, blunt tooth, which grades evenly into the ventral margin of the petiole posteriorly; ventral margin of petiole weakly bulging medially. Petiolar peduncle long: comprising slightly more than half the length of the petiole. Petiolar node robust and erect, nearly squamiform: transition between peduncle and node marked by a rounded angle of ~120 °, resulting in a concave anterior node face; anterior face rounding evenly into the dorsal face, which is convex; dorsal face rounding evenly into posterior face, which forms a ~90 ° angle with the caudal cylinder. Postpetiole flat anteriorly, bulging anterodorsally before flattening posterodorsally; ventral surface weakly lobed.

In dorsal view, mesoscutum leaving a small sliver of the anterior face of the pronotum exposed; humeri visible laterally as rounded sclerites. Propodeal spines strongly diverging apically, their apices separated from each other by about two and a half times their length. Petiolar peduncle with spiracles protruding past the lateral margins, the peduncle slightly narrowed anterior to them. Petiolar node campaniform: anterior face strongly convex; posterior face very weakly convex, nearly flat. Petiolar node wider than the peduncle, about one and a quarter times the width of the caudal cylinder. Postpetiole subquadrate and narrow (PWI 191), articulating with most of the anterior margin of the gaster, leaving small, angulate margins on each side exposed. Anterior margin of postpetiole flat, with corners marked by rounded angles as it transitions to the lateral margins, which weakly diverge to the angulate posterior corners; posterior margin flat. Metafemur strongly incrassate (FI 319).

Sculpture: median clypeal carina present but indistinct, flanked by three slightly weaker carinae on each side. Lateral clypeal lobes with additional weaker carinae; ground sculpture weakly areolate. Antennal scapes areolate. Cephalic dorsum areolate, but with fine costae overlying the ground sculpture; fine concentric costulae surrounding the antennal insertions. Lateral surfaces of head sculptured similarly to the dorsum of the head. Ventral surface of head weakly areolate-costulate. Mesosoma with areolate sculpture on the pronotal neck. Lateral surface of the mesosoma strongly areolate, with rugulose-costulate sculpture on the pronotum the border of the meso- and metapleurae. Propodeal declivity weakly areolate, with fine costulae. Mesoscutum and mesoscutellum with costulae over areolate ground sculpture. Femora areolate. Petiole and postpetiole weakly areolate, becoming weaker on the dorsum of the peduncle. First gastral tergite strongly areolate, with spectral iridescence. First gastral sternite smooth and shining, with spectral iridescence.

Setae: antennal scapes and funiculi with short, decumbent pilosity. Dorsum of the head, pronotum, waist segments, and gaster with moderately abundant, erect, blunt-tipped, nearly clavate setae, the longest of which are about a third of the width of the compound eye. Short, sparse pubescence present over the entire body, but difficult to detect against the ground sculpture and light integument.

Color: predominantly testaceous, with antennae, metanotum, protibiae and protarsi, mid legs, hind legs, and gaster medium brown.

Male: unknown.

Etymology: Matronym, for the collector of the type series, Dr. Leticia Ríos Casanova.

Comments: Temnothorax casanovai sp. nov. is known from a couple of mid elevation collections in Puebla state, Mexico. Workers were taken from pitfall traps, and a nest was collected from the branch of a pitahaya cactus, Hylocereus undatus , a hemiepiphytic species commonly cultivated for its fruit.

Figures

Figure 106 Temnothorax casanovai sp. nov. (A–C) Holotype worker (LACMENT323462). (A) Full-face view. (B) Profile view. (C) Dorsal view. (D–F) Paratype gyne (LACMENT323464). (D) Full-face view. (E) Profile view. (F) Dorsal view. (G) Geographical and elevational distribution of specimens examined. Type localities are represented by triangles, non-type localities are represented by circles. Bounding box in inset map shows location of main map. Scale bars 0.2 mm. Full-size DOI: 10.7717/peerj.11514/fig-106