Temnothorax androsanus ( Wheeler, 1905 )

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 : 205-210

Temnothorax androsanus ( Wheeler, 1905)

Distribution: Fig. 121A ; worker & variability: Fig. 122 .

Macromischa androsana Wheeler, 1905: 97 , fig. K. Syntype workers. Bahamas. One syntype here designated lectotype.

Leptothorax androsanus (Wheeler) : Baroni Urbani, 1978: 416. Gyne and male. First combination in Leptothorax .

Temnothorax androsanus (Wheeler) : Bolton, 2003: 271. First combination in Temnothorax .

Type material examined: Lectotype worker: BAHAMAS: Andros Island : May–June 1904, W.M. Wheeler Collector, M.C.Z. Type 21003, Type No. A.M.N.H. ( MCZENT00021003 , bottom specimen on pin).

Paralectotype workers: same pin as lectotype (MCZENT00021003, remaining specimens on pin) [ MCZC].

Non-type material examined: BAHAMAS: Exuma Cays: Staniel Key , May 1991, L. Morrison, leaf litter, 2 workers (CASENT0758350) [ MCZC] 2 workers (CASENT0915979) [ UCDC] .

CUBA: Camagüey: Cayo Caguama, Jardines da la Reina, 1 April 1971, L. Armas, 1 worker (images of CASENT0914182 examined on antweb.org) [ BMNH] .

Geographic range: Low elevations from the Bahamas and Cuba ( Fig. 121A ).

Worker diagnosis: Temnothorax androsanus can be separated from all other species in the salvini clade by the following character combination: antennal scape moderately long, barely surpassing the posterior margin of head; anterior margin of clypeus entire; transition between anterior and dorsal faces of pronotum marked by a distinct angle; in profile view, mesosoma strongly convex dorsally and compact (WLI 117–128); in dorsal view, mesosoma posterior to the pronotum swollen, only slightly narrower than the pronotum; dorsum of propodeum with setae; in dorsal view, propodeal spines broadly approximated basally, negative space between them “U” shaped; propodeal spines longer than the propodeal declivity, directed posteriorly, and downcurved; hind femora moderately to strongly incrassate (FI 247–443); petiolar node squamiform; dorsum of petiole with four erect setae; in dorsal view, petiolar node moderately broader than the caudal cylinder (PNWI <160); postpetiole very broad (PWI 219–262); dorsum of head uniformly areolate; dorsum of petiolar node and postpetiole shallowly areolate; setae on head, mesosoma, waist segments and gaster erect, moderately long, sparse and blunt (never long and tapering); dorsum of postpetiole with> 10 erect setae; integument bicolored: antennae, head capsule, postpetiole, and gaster medium brown; mandibles, clypeus, mesosoma, legs, and petiole testaceous yellow; tarsi and sting yellowish.

Similar species: Temnothorax misomoschus sp. nov., T. subditivus , and other members of the pastinifer group. Temnothorax androsanus can be distinguished from T. subditivus by the narrower petiolar node in dorsal view (PNWI <160 vs.> 160 in T. subditivus ), the somewhat shorter petiolar peduncle (~2/3 of the total petiole length in T. androsanus vs. ~ 3/ 4 in T. subditivus ) and the sculpture of the head dorsum (uniformly areolate in T. androsanus vs. variable in T. subditivus , but never uniformly areolate). In contrast to T. androsanus , T. misomoschus sp. nov. is devoid of erect setae on most surfaces of the body, has a depressed propodeum, and a posteriorly leaning, subquadrate petiolar node. Temnothorax androsanus can be separated from other members of the pastinifer group by the areolate head (smooth and shining in T. schwarzi ), flat to weakly convex anterior clypeus margin (strongly emarginate in T. pastinifer ), and the angulate transition between the anterior and dorsal faces of the pronotum in profile view (transition indistinct in T. nigricans ).

Worker measurements & indices (n = 9): SL = 0.467 –0.528 (0.492); FRS = 0.161 –0.206 (0.186); CW = 0.510 –0.612 (0.564); CWb = 0.466 –0.565 (0.521); PoOC = 0.214 –0.253 (0.235); CL = 0.548 –0.657 (0.600); EL = 0.112 –0.151 (0.130); EW = 0.084 –0.117 (0.098); MD = 0.134 –0.160 (0.149); WL = 0.598 –0.706 (0.643); SPST = 0.205 –0.290 (0.248); MPST = 0.189 –0.230 (0.210); PEL = 0.239 –0.295 (0.259); NOL = 0.124 –0.164 (0.146); NOH = 0.115 –0.150 (0.134); PEH = 0.213 –0.249 (0.225); PPL = 0.152 –0.189 (0.166); PPH = 0.173 –0.219 (0.200); PW = 0.338 –0.404 (0.373); SBPA = 0.144 –0.185 (0.161); SPTI = 0.216 –0.262 (0.239); PEW = 0.125 –0.152 (0.141); PNW = 0.190 –0.225 (0.204); PPW = 0.309 –0.346 (0.324); HFL = 0.417 –0.511 (0.460); HFWmax = 0.125 –0.155 (0.140); HFWmin = 0.035 –0.053 (0.047); CS = 0.740 –0.894 (0.821); ES = 0.154 –0.210 (0.179); SI = 87–102 (95); OI = 20–23 (22); CI = 84–92 (87); WLI = 117–128 (124); SBI = 27–35 (31); PSI = 34–43 (38); PWI = 219–262 (231); PLI = 139–177 (157); NI = 94–140 (110); PNWI = 140–156 (145); NLI = 51–64 (57); FI = 247–443 (306).

Worker description: In full-face view, head subquadrate, longer than broad (CI 84–92). Mandibles moderately 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 flat to weakly convex medially. Antennal scapes moderately long: when fully retracted, surpassing the posterior margin of the head capsule by about the maximum width of the antennal scape (SI 87–102). Antennae 12-segmented; antennal club of three segments, with the apical-most segment slightly longer than the preceding two in combination. Frontal carinae very 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, converging evenly to the mandibular insertions. Posterior head margin flat to very slightly concave, rounding evenly into the lateral margins.

In profile view, compound eyes ovular and moderately large (OI 20–23), with 12 ommatidia in longest row. Pronotal declivity distinct: pronotal neck and anterior face of pronotum forming a rounded ~120 ° angle; anterior face and dorsal face forming a rounded ~120 ° angle. Mesosoma evenly, but weakly, convex dorsally from where it joins the anterior face of the pronotal declivity to the propodeal spines. Promesonotal suture extending from the posterior margin of the procoxal insertion only to the mesothoracic spiracle, which is barely visible against the ground sculpture. Metanotal groove nearly entirely absent: only visible as a faint disruption in the surface sculpture between meso- and metacoxal insertions to the minute metathoracic spiracle, which is nearly indistinguishable from the ground sculpture. Propodeal spiracle well developed, directed posterolaterally, and separated from the propodeal declivity by about two and a half spiracle diameters. Propodeal spines well developed and long (PSI 34–43), slightly longer than the propodeal declivity, tapering evenly from the base, evenly downcurved, and acute. Propodeal declivity weakly concave, forming a rounded ~100 ° angle with the base of the propodeal spines. Propodeal lobes rounded and weakly developed, but with a slightly angulate dorsal flange. Metapleural gland bulla large, extending from the metacoxal insertion three quarters of the way to the propodeal spiracle. Petiole moderately long (PLI 139–177), with peduncle evenly rounded anterodorsally. Subpetiolar process in the form of a weakly developed, blunt tooth, which grades evenly into the ventral margin of the petiole posteriorly. Ventral surface of petiole bulging medially. Petiolar peduncle long, comprising about two thirds of the total length of the petiole. Petiolar node squamiform: transition between peduncle and node marked by a rounded angle of ~90 °, resulting in a weakly concave anterior node face that slightly overtops the peduncle; anterior face forming a slightly rounded ~90 ° angle with the dorsal face, which rounds evenly into the very short posterior face. Postpetiole evenly rounded and bulging anterodorsally, before flattening posterodorsally; weakly lobed ventrally.

In dorsal view, humeri very weakly developed: rounded and only slightly wider than the rest of the mesosoma; mesothoracic spiracles protruding past the lateral margins of the mesosoma, noticeable as slight angles where the pronotum joins the rest of the mesosoma. Metanotal groove absent: mesonotum and propodeum completely fused and converging evenly to the bases of the propodeal spines. Propodeal spines broadly approximated basally and diverging apically, their apices separated from each other by their length; negative space between them a “U”. Petiolar peduncle with spiracles protruding past the lateral margins, the peduncle broadened where they arise. Petiolar node squamiform: rounded anteriorly, with an indistinct posterior face, much wider than the peduncle, and narrowing into the caudal cylinder, which is narrower than the node. Postpetiole very broad (PWI 219–262) and campaniform, articulating with nearly the entire anterior margin of the gaster, but leaving angulate corners of the gaster exposed on each side. Anterior margin of the postpetiole broadly convex, meeting the lateral margins at rounded angles; lateral margins diverge evenly anteriorly, but flare laterally as they approach the gaster; posterior margin broadly concave. Metafemur moderately to strongly incrassate (FI 247–443).

Sculpture: median clypeal carina present, flanked by two equally strong carinae over weakly areolate-costulate ground sculpture. Antennal scapes weakly areolate and appearing dull. Cephalic dorsum and lateral surfaces of head densely areolate; ventral surface of head shining through weaker areolate sculpture. Mesosoma areolate-costulate, with cross-reticulations on the dorsal face of the pronotum; pronotal declivity lacks costulae; area between the propodeal spiracle and base of the propodeal spines, as well as the propodeal declivity, shining through weak areolae. Femora weakly shining through areolate sculpture. Petiolar peduncle, venter, and anterior face of the petiolar node shining through shallow areolate sculpture; dorsal face of the petiolar node more densely areolate. Dorsal surface of postpetiole dull with areolate sculpture. Gaster smooth and shining, without spectral iridescence on the first tergite. Surface of the first gastral sternite smooth and shining.

Setae: antennal scapes and funiculi with short, adpressed pilosity. Dorsum of head, mesosoma, waist segments and gaster with short, erect, blunt-tipped setae, the longest of which are roughly the width of the compound eye. The head bears ~38, mesosoma ~36, petiole 4, postpetiole ~14, and first gastral tergite ~46 setae. Sparse, adpressed pubescence present on the entire body, but may be difficult to discern from the dense ground sculpture on most of the body.

Color: antennae, head capsule, postpetiole, and gaster medium brown. Mandibles, clypeus, mesosoma, legs, and petiole testaceous yellow. Tarsi and sting are yellowish.

Gyne: see Baroni Urbani, 1978.

Male: see Baroni Urbani, 1978.

Etymology: Geographical, in reference to the type locality of Andros Island.

Comments: Similar to other members of the pastinifer and pulchellus groups (e.g., T. pastinifer , T. rutabulafer sp. nov., T. torrei ), T. androsanus appears to have a Bahamian-Cuban distribution. This species, like other members of the pastinifer group, is only known from littoral habitats. Wheeler notes that the syntype workers were found under dead palmetto leaves near Crawl Creek in present day Southern Andros, but that the nests were not located. This species, like other members of the pastinifer and pulchellus groups, most likely nests in dead twigs in the leaf litter. A dark form of T. androsanus is present on the Exuma Cays: other than being uniformly dark brown, it differs from the type series by having relatively weakly incrassate femora, relatively narrow petiolar node, and having a smooth and shining dorsum of petiole and postpetiole ( Figs. 122D–122F ). If these two forms represent different species, they are surely close relatives. However, despite these morphological differences I unite the two forms as one species here, as I have not yet seen evidence of the two forms existing in sympatry.

Figures

Figure 121 Geographical and elevational distribution of the pastinifer group. (A) Temnothorax androsanus (B) T. nigricans (C) T. pastinifer (D) T. rutabulafer sp. nov. (E) T. schwarzi. 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; if present, types of synonyms are named; non-type localities are represented by circles. Bounding box in inset map shows location of main map. Full-size DOI: 10.7717/peerj.11514/fig-121

Figure 122 Temnothorax androsanus. (A–C) Lectotype worker (MCZENT00021003). (A) Full-face. (B) Profile view. (C) Dorsal view. (D–F) Dark form of Temnothorax androsanus (CASENT0758350). (D) Full-face. (E) Profile view. (F) Dorsal view. Scale bars 0.2 mm. Full-size DOI: 10.7717/peerj.11514/fig-122