Temnothorax mpala Prebus

Prebus, Matthew, 2015, Palearctic elements in the old world tropics: a taxonomic revision of the ant genus Temnothorax Mayr (Hymenoptera, Formicidae) for the Afrotropical biogeographical region, ZooKeys 483, pp. 23-57 : 33-39

Taxon classification Animalia Hymenoptera Formicidae

Temnothorax mpala Prebus sp. n. Figs 1, 2a and c, 3b and d, 9, 10, 11

Type material.

Holotype worker: 1 worker: KENYA, Laikipia District, Mpala Research Centre, 0.28°N, 36.87°E, 1700m, 18.III.2001 "Black Cotton" ex. pitfall trap in No. exclosure (D. Misurelli) (BMNH: LACMENT323183). Paratypes: 1 dealate queen: same data as previous (CASENT0733785). 1 worker, 1 dealate queen: same data as previous (NHMW: LACMENT323184). 1 male, 1 dealate queen: same data as previous (BMNH: LACMENT323185). 2 workers, 1 dealate queen: same data as previous (HLMD: LACMENT323186). KENYA, Laikipia District, Mpala Research Centre, 1650 m, 0.29°N, 36.90°E, Acacia woodland, ex pitfall trap near centre, collection code #01-225, 12.IV.2001 (R.R. Snelling) (BMNH: CASENT0280870). 1 worker, 1 dealate queen: same data as previous (LACM: CASENT0712602).

Diagnosis.

Temnothorax mpala is easily distinguishable from the other Afrotropical species by the following character combination:

Antennal scapes short, distinctly failing to reach the posterior margin of the head; compound eyes large; post petiole trapezoidal in dorsal view, widest at the anterior 1/5 of the segment; metanotal groove absent; head subrectangular; posterior margin of head flat; setae on the posterior margin of the first gastric tergite separated by about their own length; pilosity on antennal scape short and adpressed.

Worker measurements

(n = 6). EL 0.168-0.193 (0.185); FRS 0.175-0.19 (0.182); HL 0.598-0.67 (0.631); HW 0.445-0.488 (0.465); IOD 0.343-0.372 (0.355); IOcD N/A; MD 0.134-0.157 (0.142); PH 0.195-0.22 (0.205); PL 0.2-0.233 (0.218); PPH 0.172-0.185 (0.179); PPL 0.125-0.154 (0.142); PPW 0.216-0.239 (0.227); PTW 0.156-0.174 (0.162); PW 0.34-0.373 (0.354); SL 0.43-0.467 (0.443); SPST 0.161-0.183 (0.166); WL 0.705-0.772 (0.733).

Indices: CI 72.8-75.9 (73.6); DPeI 71.1-83 (74.5); DPpI 150.7-178.4 (160.7); LPeI 95-112 (107); LPpI 71.4-83.7 (79.2); OI 37-41.6 (39.8); PeNI 45-46.8 (45.9); PpNI 62.2-65.8 (64.1); PPI 134.9-145.1 (139.7); PSLI 25.4-27.3 (26.3); SI 68.3-72.6 (70.2).

Worker description.

Head subrectangular, longer than wide (CI 72.8-75.9); head sides parallel, but converging toward the mandibular insertions anteriorly beyond the level of the antennal insertions in full-face view; posterior head margin flat and posterior corners of head broadly rounded. Anterior clypeal margin convex and entire, with the median clypeal lobe projecting slightly beyond the lateral clypeal lobes. Frontal carinae poorly developed: extending posteriorly about one-quarter the length of the compound eye. Antennae 12-segmented; antennal scapes short, failing to reach the posterior margin of the head (SI 91.3-98.9). Eyes large (OI 37.0-41.6). with 11 ommatidia in longest row.

Mesosoma compact (WL 1.17 times HL); promesonotal suture absent. Metanotal groove not impressed, but marked by a faint narrowing of the dorsal surface of the mesosoma in dorsal view. Propodeal spines acute and relatively short (PSLI 25.4-27.3); propodeal lobes small and rounded.

Petiole without a differentiated peduncle. In profile, the anterior face of node forming a very shallow concavity anteriorly as it joins the anterior portion of the petiole. Petiolar node in profile low (LPeI 95.0-112), with dorsal and posterior faces joined by a rounded 120° angle. Subpetiolar process is in the form of a small tooth in the anterior 1/4 of the petiole. In dorsal view petiole somewhat elongate (DPeI 71.1-83.0). Postpetiole in profile with proximal half of dorsal margin evenly rounded, and distal half forming an even declivity; slightly shorter than petiolar node and laterally compressed (LPpI 71.4-83.7). In dorsal view postpetiole trapezoidal and wider than long (DPpI 151-153), widest in the anterior 1/4, and 1.4-1.5 times wider than petiole (PPI 135-145).

Mandibular sculpture: longitudinally striate along entire length. Clypeus smooth and shiny, bearing 9 longitudinal rugae, with median ruga strongly developed and running posteriorly from the anterior clypeal margin to the level of antennal insertions before weakening. Cephalic dorsum reticulate, with transverse rugae becoming weaker posterior to the level of the compound eyes. In profile, head irregularly reticulate-punctate. Sculpture of mesosoma in dorsal view punctate, with overlying weak reticulation on pronotum. Space between propodeal spines with a single extremely fine, arcuate transverse carina, which divides the propodeal dorsum from the declivity. Propodeal declivity uniformly punctate, bordered laterally by carinae which run from the ventral margins of the propodeal spines to the propodeal lobes. In profile, mesosoma predominantly irregularly punctate; humeri weakly reticulate. Petiole and postpetiole finely punctate. Gaster smooth and shining except for small, widely spaced piligerous punctures.

Head, including mandibles, with a short, sparse, adpressed fine yellowish pubescence. Mandibles with longer setae along the distal margins. Posterior margin of clypeus with one pair of short, stout setae directly below the antennal insertions. Frontal carinae with three pairs of stout setae, located at the level of the antennal insertions, anterior margin of the compound eye, and midway up the compound eye. Region of the head posterior to the level of the compound eyes equipped with three pairs of short, blunt-tipped setae: one located medially, posterior to the level of the compound eyes and two pairs on the posterior margin of the head. Anterior clypeal margin with two pairs of long setae flanking the median carina. Scapes with abundant, short subdecumbant pilosity. Pronotal “neck” with pubescence similar to that which is found on the head. Propleurae with several short, sharp-tipped setae. Procoxae with short, adpressed and abundant pilosity. Pronotal humeri free of pubescence. Dorsal surfaces of mesosoma and waist segments with uniformly erect, short, sparse and spatulate setae; their bases spaced from each other by more than the length of the setae which arise from them. All surfaces of gaster covered in sparse, evenly spaced short pilosity. Dorsal surface of first gastral tergite largely free of setae longer than the ground pilosity, save for several irregularly spaced stout setae. Anterior margins of all gastral tergites with evenly spaced short, stout setae. Ventral surfaces of the post-petiole with several short, fine setae. Ventral surface of gaster with abundant long fine pilosity.

Queen measurements

(n = 4). EL 0.241-0.248 (0.245); FRS 0.212-0.218 (0.214); HL 0.68-0.71 (0.699); HW 0.534-0.551 (0.543); IOD 0.411-0.427 (0.421); IOcD 0.139-0.148 (0.142); MD 0.131-0.143 (0.139); PH 0.232-0.259 (0.246); PL 0.242-0.29 (0.265); PPH 0.224-0.232 (0.228); PPL 0.162-0.177 (0.169); PPW 0.277-0.295 (0.283); PTW 0.192-0.207 (0.201); PW 0.484-0.501 (0.491); SL 0.459-0.489 (0.481); SPST 0.214-0.221 (0.217); WL 1.029-1.07 (1.054).

Indices: CI 76.8-78.5 (77.7); DPeI 71.4-83.1 (76.2); DPpI 163.9-172.8 (167.7); LPeI 98-116 (108); LPpI 71.1-76.3 (74); OI 45-45.4 (45.1); PeNI 39.7-41.8 (41); PpNI 57.1-58.9 (57.7); PPI 136.6-144.3 (140.8); PSLI 30.5-31.5 (31.1); SI 67.5-69.4 (68.8).

Queen description.

Head subrectangular, longer than wide (CI 76.8-78.5); head sides parallel, but converging toward the mandibular insertions anteriorly beyond the level of the antennal insertions in full-face view; posterior head margin flat; posterior corners of head more broadly rounded than in the worker. Anterior clypeal margin convex and entire, with the median clypeal lobe projecting slightly beyond the lateral clypeal lobes. Frontal carinae developed: extending posteriorly to about one-half the length of the compound eye. Antennae 12-segmented;antennal scapes short, failing to reach the posterior margin of the head (SI 86.0-89.9). Eyes large (OI 45.0-45.5). with 14-16 ommatidia in longest row. Three ocelli present.

Mesosoma more massive and elongate than in the worker (WL 1.51 times HL).Scutum and scutellum forming an even, flat surface in profile, broken only by the suture between the two tergites. Propodeal declivity steep. Propodeal spines acute and slightly longer than in the worker (PSLI 30.5-31.5); propodeal lobes small and rounded.

Petiole without a differentiated peduncle. In profile, the anterior face of node not forming a shallow concavity anteriorly as it joins the anterior portion of the petiole. Petiolar node in profile relatively low and truncate (LPeI 98.0-116), junction of anterior and dorsal faces forming a rounded 120° angle; dorsal and posterior faces differen tiated by a rounded 135° angle. Subpetiolar process is in the form of a small tooth at the anterior 1/4 of the petiole. In dorsal view petiole elongate (DPeI 71.4-83.1). Postpetiole in profile with proximal half of dorsal margin evenly rounded, and distal half forming an even declivity; slightly shorter than petiolar node and laterally compressed (LPpI 71.1-76.3). In dorsal view postpetiole trapezoidal and wider than long (DPpI 164-173); widest in the anterior 1/4, and 1.4 times wider than petiole (PPI137-144).

Mandibular sculpture: longitudinally irregularly striate along entire length. Clypeus smooth and shiny, bearing 5 longitudinal rugae and a few irregular rugae on posteriorly; median ruga strongly developed and running posteriorly from the anterior clypeal margin to the level of antennal insertions before weakening. Cephalic dorsum with closely spaced longitudinal rugae, extending the entire length of the head. In profile, gena anterior to the compound eye strongly reticulate. Scutum and scutellum with light longitudinal rugae and shallow foveae, becoming smooth and polished on the anterior of the scutum in some specimens; propodeum reticulate. Space between propodeal spines with a single arcuate transverse carina, which divides the propodeal dorsum from the declivity. Propodeal declivity weakly reticulate. In profile, mesosoma predominantly longitudinally rugose; anterior of pronotum reticulate; sculpture weakening slightly on mesopleuron. Petiole and postpetiole finely punctate; dorsum of postpetiole reticulate. Gaster smooth and shining except for small, widely spaced piligerous punctures.

Head, including mandibles, with a short, sparse, adpressed fine yellowish pubescence. Mandibles with longer setae along the distal margins. Posterior margin of clypeus with one pair of short, stout setae directly below the antennal insertions. Frontal carinae with three pairs of stout setae, located at the level of the antennal insertions, anterior margin of the compound eye, and midway up the compound eye. Posterior of head equipped with three pairs of short, blunt-tipped setae; one flanking the anterior ocellus, and two pairs on posterior margin of the head. Anterior clypeal margin with two pairs of long setae flanking the median carina. Scapes with abundant, short, subdecumbant pilosity. Pronotal “neck” with pubescence similar to that which is found on the head. Propleurae with several short, fine setae.Coxae with short, thin and sparse setae. Dorsal surfaces of mesosoma, waist segments and gaster with uniformly erect, sparse and blunt-tipped bristle-like setae. Dorsum of mesosoma with fine, short, sparse yellowish setae. Ventral surface of the petiole free of pilosity, but post-petiole has a pair of hairs latero-ventrally. All surfaces of gaster with short, fine, yellowish pilosity which becomes longer ventrally.

Male measurements

(n = 1). EL 0.222; FRS 0.123; HL 0.498; HW 0.419; IOD 0.271; IOcD 0.131; MD 0.044; PH 0.151; PL 0.22; PPH 0.151; PPL 0.142; PPW 0.196; PTW 0.14; PW 0.487; SL 0.262; SPST N/A; WL 0.957.

Indices: CI 84.1; DPeI 63.6; DPpI 138; LPeI 146; LPpI 94; OI 53; PeNI 28.7; PpNI 40.2; PPI 140; PSLI N/A; SI 52.6.

Male description.

Head globular, small and somewhat longer than wide (CI 84.1); head sides rounding broadly into the posterior of the head. Anterior clypeal margin convex and entire, with the median clypeal lobe projecting strongly beyond the lateral clypeal lobes. Frontal carinae developed: extending posteriorly to the posterior margin of the compound eye. Antennae 13-segmented, with a four-segmented club;antennal scapes very short, failing to reach the posterior margin of the head (SI 62.5). Eyesvery large (OI 53) and close to the mandibular insertions (MD 0.044). 20 ommatidia in longest row. Three ocelli present.

Mesosoma more massive and elongate than in the worker (WL 1.92 times HL).Scutum and scutellum forming an even, flat surface in profile, broken only by the suture between the two tergites. Dorsal surface of propodeum rounding evenly into the propodeal declivity. Propodeal spines absent.

Petiole without a differentiated peduncle. In profile, petiolar node indistinct, forming a low mass (LPeI 146). Subpetiolar process reduced to a small bump in the anterior 1/4 of the petiole in profile. In dorsal view petiole elongate (DPeI 63.6). Postpetiole in profile with proximal half of dorsal margin evenly rounded, and distal half forming an even declivity; slightly shorter than petiolar node (LPpI 94). In dorsal view postpetiole weakly trapezoidal and slightly wider than long (DPpI 138);slightly wider in the anterior half, and 1.4 times wider than petiole (PPI140).

Mandibular sculpture: smooth and shiny along their entire length. Clypeus smooth and shiny, bearing several irregular rugae. Cephalic dorsum with closely spaced longitudinal rugae with slightly weaker reticulations and punctuations between them. Scutum and scutellum with light longitudinal rugae, becoming smooth and polished on the anterior half of the scutum; propodeum weakly reticulate over a punctate ground sculpture. Propodeal declivity weakly punctate. In profile, mesosoma predominantly smooth and shiny; anterior of pronotum, dorsal margin of the anepisternum and propodeum weakly punctate. Petiole and postpetiole finely punctate; dorsum of postpetiole smooth and weakly punctate. Gaster smooth and shining except for small, widely spaced piligerous punctures.

Head, including mandibles, with a short, sparse, adpressed fine yellowish pubescence. Mandibles with longer setae along the distal margins. Posterior margin of clypeus with one pair of short, stout setae directly below the antennal insertions. One pair of short, blunt-tipped setae flank the anterior ocellus. Scapes with abundant, short, subdecumbant pilosity. Pronotal “neck” with pubescence similar to that which is found on the head. Propleurae with several short, fine setae.Coxae with short, thin and sparse setae. Dorsal surfaces of mesosoma and waist segments with uniformly erect, sparse and blunt-tipped bristle-like setae. Dorsum of mesosoma with fine, short, and very sparse setae. Ventral surface of the petiole free of pilosity, but post-petiole has a pair of hairs latero-ventrally. All surfaces of gaster with fine, yellowish, sparse pilosity which becomes longer ventrally.

Color.

Worker: Overall light brownish-yellow, with slightly darker head and gaster and lighter legs (including coxae).

Queen: Same as worker, but with dorsum of mesosoma same color as head and mesosoma.

Male: Overall dark reddish brown, with ventral surfaces of waist segements slightly lighter. Extemities, including antennae, mouthparts, legs and coxae cream-colored.

Distribution and ecology.

Temnothorax mpala is only known from the leaf litter of acacia woodland at the type locality, Mpala Research Centre. Curiously, workers, dealate gynes as well as one male were recovered from pitfall traps, suggesting that these collection events captured a nest migration.

Taxonomic notes.

The word “mpala” comes from a Bantu name for a type of antelope that was kept by chiefs of the Bunganda kingom. Temnothorax mpala is not expected to be particularly swift in its movements; the only known specimens were collected at the above mentioned Mpala Research Centre in Laikipia, Kenya.