Temnothorax achii, 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 : 175-180

Temnothorax achii sp. nov.

Distribution: Fig. 114A ; worker: Fig. 115 .

Temnothorax mmp04 Prebus, 2017: 8. In phylogeny.

Type material examined: Holotype worker: GUATEMALA: El Progreso: 3.7 km SW Morazán , 14.9051 ° N - 90.15362 ° W, 460 m, 7 July 2007, J. Longino #6002-s , tropical dry forest, ex sifted leaf litter ( JTLC000009876 ) [ CASC].

Paratype workers: same data as holotype, 1 worker ( JTLC000009871 ) [ MCZC] 1 worker ( JTLC000009906 ) [ USNM] 1 worker (CASENT0869159) [ LACM] 1 worker (CASENT0869160) [ UVGC]; same data as holotype, except: M.G. Branstetter #626-12, tropical dry scrub, ex sifted leaf litter, 1 worker (CASENT0600922) [ UCDC] .

Non-type material examined: GUATEMALA: Chiquimula: 15 km W Chiquimula, 14.77968 ° N 89.67686 ° W ± 50 m, 1,735 m, 27 April 2014, M. Barrios #MB1314, second growth oak cloud forest, ex sifted leaf litter, 1 worker (CASENT0758686) [ UCDC] ; Baja Verapaz: 1 km SSW La Cumbre , 15.033333 ° N 90.216667 ° W, 1,480 m, 19 November 2003, P.S. Ward #15097-14, mixed tropical/temperate mesic forest, sifted litter (leaf mold, rotten wood), 3 workers (CASENT0915976) [ UCDC] .

Geographic range: Low-to-mid elevations in central Guatemala (Baja Verapaz, Chiquimula, El Progreso) ( Fig. 114A ).

Worker diagnosis: Temnothorax achii sp. nov. 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 capsule by about the maximum width of the scape (SI 85–90); compound eyes small (OI 22–26); body moderately compact (WLI 137–143); metanotal groove absent; propodeum not strongly depressed; propodeal spines shorter than the propodeal declivity and dentate (PSI 25–28); propodeal spines broadly approximated in dorsal view (SBI 28–34); hind femora weakly to moderately incrassate (FI 180–303); petiolar node erect and dorsally rounded, not overhanging the caudal cylinder in profile view; petiolar node compact, not elongate (NI 143–170); petiolar node very slightly broader than caudal cylinder in dorsal view (PNWI <115); head sculpture areolate, with areolae arranged into columns by costulae; dorsum of postpetiole sculptured; antennal scapes with short, decumbent pilosity; setae on head, mesosoma, waist segments and gaster erect, short, sparse and blunt (never long and tapering); integument predominantly dark brown, with trochanters, meso- and metacoxae, tibiae, tarsi, and sting very light yellow.

Similar species: Temnothorax acutispinosus sp. nov., T. altinodus sp. nov., T. tuxtlanus sp. nov., T. subditivus , species of the augusti , goniops , and pulchellus groups, species of the sallei clade. Temnothorax achii sp. nov. can be distinguished from similar appearing members of the sallei clade (e.g., T. manni , T. mexicanus , T. punctithorax ) by the petiole, which lacks a transverse carina anterodorsally. Unlike the long, dorsally directed propodeal spines of T. acutispinosus sp. nov., T. achii sp. nov. has short propodeal teeth that are directed posterodorsally. Temnothorax achii sp. nov. has a moderately broad postpetiole in dorsal view, whereas T. tuxtlanus sp. nov. has a relatively narrow postpetiole (PWI <150). Temnothorax altinodus sp. nov. has comparatively strongly incrassate hind femora (FI 327). Temnothorax achii sp. nov. can be separated from T. subditivus and the augusti group by the structure of the petiolar node, which is erect, dorsally rounded, and only slightly broader than the caudal cylinder in dorsal view, as opposed to squamiform in T. subditivus , or leaning posteriorly over the caudal cylinder in the augusti group. Temnothorax achii sp. nov. can be distinguished from the pulchellus group by the combination of a relatively longer mesosoma (WLI> 135 vs. <135 in most pulchellus group members). Some members of the pulchellus group may approach these dimensions (e.g., T. agavicola sp. nov., T. albispinus , T. flavidulus , T. hippolytus sp. nov., T. laticrus sp. nov., T. terricola , T. torrei , and T. wilsoni sp. nov.), but they can be separated from T. achii sp. nov. by their very broad postpetioles (PWI> 220). Temnothorax achii sp. nov. can be distinguished from other goniops group members by the short, dentate propodeal spines (longer than the propodeal declivity and spiniform in T. goniops and T. huehuetenangoi ), the areolate-rugulose head and postpetiole (smooth and shining in T. xincai sp. nov.), and the relatively narrow, rugulose petiolar node (narrower, on average, in T. achii sp. nov. and uniformly areolate).

Worker measurements & indices (n = 6): SL = 0.375 –0.444 (0.418); FRS = 0.165 –0.181 (0.174); CW = 0.485 –0.561 (0.524); CWb = 0.442 –0.519 (0.479); PoOC = 0.220 –0.253 (0.235); CL = 0.541 –0.633 (0.582); EL = 0.114 –0.146 (0.136); EW = 0.090 –0.112 (0.104); MD = 0.113 –0.142 (0.121); WL = 0.611 –0.744 (0.668); SPST = 0.157 –0.201 (0.177); MPST = 0.196 –0.244 (0.220); PEL = 0.258 –0.308 (0.286); NOL = 0.142 –0.184 (0.161); NOH = 0.098 –0.109 (0.102); PEH = 0.168 –0.198 (0.185); PPL = 0.156 –0.205 (0.176); PPH = 0.176 –0.212 (0.195); PW = 0.308 –0.389 (0.340); SBPA = 0.128 –0.175 (0.145); SPTI = 0.169 –0.235 (0.194); PEW = 0.136 –0.152 (0.146); PNW = 0.148 –0.184 (0.164); PPW = 0.265 –0.309 (0.293); HFL = 0.402 –0.474 (0.443); HFWmax = 0.081 –0.129 (0.112); HFWmin = 0.040 –0.046 (0.044); CS = 0.713 –0.836 (0.77); ES = 0.159 –0.199 (0.188); SI = 85–90 (87); OI = 22–26 (24); CI = 82–85 (82); WLI = 137–143 (139); SBI = 28–34 (30); PSI = 25–28 (26); PWI = 191–208 (200); PLI = 150–170 (163); NI = 143–170 (157); PNWI = 109–121 (112); NLI = 50–60 (56); FI = 180–303 (256).

Worker description: In full-face view, head subquadrate, longer than broad (CI 82–85). Mandibles densely, 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 evenly convex medially. Antennal scapes short: when fully retracted, failing to reach the posterior margin of the head capsule by about the maximum width of the scape (SI 85–90). Antennae 12-segmented; antennal club of composed of three segments, with the apical-most segment longer than the preceding two in combination. Frontal carinae moderately long, extending past the antennal toruli by about three times the maximum width of the antennal scape. Compound eyes moderately protruding past the lateral margins of the head capsule. Lateral margin of head very weakly convex, nearly flat, forming a continuous low arc from the mandibular insertions to the posterior margin of the head. Posterior head margin weakly concave medially but rounding evenly into the lateral margins.

In profile view, compound eyes ovular, longitudinally elongate, and moderately large (OI 22–26), with 10 ommatidia in longest row. Pronotal declivity indistinct, but neck and anterior face of pronotum forming a ~120 ° angle. Mesosoma convex from where it joins the pronotal neck to the propodeal spines; propodeum slightly flatter, giving the dorsum of the mesosoma a weakly sinuate profile. Promesonotal suture extending from the posterior margin of the procoxal insertion to the mesothoracic spiracle, which is moderately well developed; continuing dorsally as a weak sulcus. 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 two and a half spiracle diameters. Propodeal spines poorly developed and short (PSI 25–28), about two thirds the length of the propodeal declivity, flared at the base, straight, and acute. Propodeal declivity with weak carinae extending between the base of the propodeal spines and the propodeal lobes; declivity straight, forming a rounded ~120 ° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed. Metapleural gland bulla small, extending from the metacoxal insertion halfway to the propodeal spiracle. Petiole moderately long (PLI 150–170), without tubercles anterodorsally. Subpetiolar process in the form of a small, triangular, acute tooth; ventral margin of petiole flat posteriorly to it. Petiolar peduncle short: comprising about a third of the petiole length. Petiolar node robust and rounded: node transitioning evenly into the petiolar peduncle, resulting in a concave anterior node face; anterior face rounding evenly into the dorsal face; dorsal face rounding evenly into the short posterior face, which forms a ~110 ° angle with the caudal cylinder. Postpetiole evenly rounded anteriorly, convex dorsally, and weakly lobed ventrally.

In dorsal view, humeri poorly developed: evenly rounded and only slightly wider than the rest of the mesosoma; mesothoracic spiracles not protruding past the lateral margins of the mesosoma. Promesonotal suture visible as a weak sulcus. Metanotal groove absent: mesonotum and propodeum completely fused and lateral margins converging evenly to the bases of the propodeal spines. Propodeal spines broadly approximated basally and diverging apically, their apices separated from each other by about their length, the negative space between them “U” shaped. Petiolar peduncle with spiracles very weakly protruding past the lateral margins, not noticeably constricted anterior to them. Petiolar node campaniform: evenly convex anteriorly, flattened posteriorly; node slightly wider than the peduncle, but narrower than the caudal cylinder. Postpetiole moderately broad (PWI 191–208) and campaniform, articulating with most of the anterior margin of the gaster, leaving small, angulate margins on each side exposed. Anterior margin of the postpetiole flat and evenly rounds into the lateral margins, which diverge slightly to the angulate posterior corners; posterior margin flat. Metafemur weakly to moderately incrassate (FI 180–303).

Sculpture: median clypeal carina present, extending posteriorly nearly to the frontal triangle, and flanked on either side by a slightly weaker carinae. Lateral clypeal lobes with additional, weaker carinae; ground sculpture very weakly areolate. Antennal scapes weakly areolate. Cephalic dorsum finely areolate, but areolae arranged into longitudinal columns by costulae which flank the frontal carinae medially and extend to the posterior margin of the head; concentric costulae surrounding the antennal insertions. Lateral surfaces of head uniformly weakly areolate-costulate, with dense rugose sculpture between the compound eye and the mandibular insertion. Ventral surface of head smooth and shining anteriorly, weakly areolate posteriorly. Mesosoma uniformly areolate-rugulose, but sculpture surrounding the propodeal spiracle costulate; propodeal declivity shining through very weak areolate sculpture. Femora shining through traces of shallow areolate sculpture, which becomes stronger distally. First gastral tergite and sternite smooth and shining, with weak 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 setae, the longest of which are about the width of the compound eye. The head bears ~28, mesosoma ~20, petiole 6, postpetiole ~12, and first gastral tergite ~46 setae. Longer, flexuous setae on the gular region, and the ventrites of the gaster. Short, sparse pubescence present over the entire body, but difficult to detect against the densely sculptured integument.

Color: predominantly dark brown, with mandibles and antennae testaceous yellow. Femora medium brown. Trochanters, Meso- and metacoxae, tibiae, tarsi, and sting very light yellow, nearly white.

Gyne: Unknown.

Male: Unknown.

Etymology: Geographical, from ‘achi’, one of the many Mayan dialects spoken by the indigenous people of Guatemala.

Comments: Temnothorax achii sp. nov. has been collected from Winkler leaf litter extractions in several localities in Central Guatemala, spanning low-to-mid elevation tropical and mesic forests. This species is closely related to T. ixili , which is also known from low to mid elevation leaf litter extractions and nests in Oncidium orchids. They have not been collected at the same locality, but collections of T. ixili and T. achii sp. nov. were taken about 15 km apart from each other. I consider them sympatric species.

Figures

Figure 114 Geographical and elevational distribution of the goniops group. (A) Temnothorax achii sp. nov. (B) T. goniops (C) T. ixili (D) T. xincai sp. nov. Colored scale to the left of each map represents elevation in meters. Points in black represent the species named in each subfigure, while points in red represent other members of the species group. Type localities are represented by triangles, non-type localities are represented by circles. Bounding box in inset map shows location of main map. Map for T. huehuetenangoi not included due to the uncertainty of the collection locality. Full-size DOI: 10.7717/peerj.11514/fig-114

Figure 115 Temnothorax achii sp. nov. holotype worker (JTLC000009876). (A) Profile view. (B) Full-face view. (C) Dorsal view. Scale bars 0.2 mm. Full-size DOI: 10.7717/peerj.11514/fig-115