Pheidole decepticon, Fischer & Fisher, 2013

FISCHER, G. & FISHER, B. L., 2013, A revision of Pheidole Westwood (Hymenoptera: Formicidae) in the islands of the Southwest Indian Ocean and designation of a neotype for the invasive Pheidole megacephala, Zootaxa 3683 (4), pp. 301-356 : 316-319

Pheidole decepticon sp. n.

( Figs. 15A–F )

Holotype: (major worker), MAYOTTE, Mont Chongui , 12.95945 S, 45.1341 E, 380 m, rainforest , ex rotten log, collection code BLF18916, 28.xi.2007 (B.L. Fisher et al.) ( CASC: CASENT0132558 ).

Paratypes: (3 major & 10 minor workers), Mont Chongui , 12.95945 S, 45.1341 E, 380 m, rainforest, sifted leaf litter, collection code BLF18922, 28.xi.2007 (B.L. Fisher et al.) ( BMNH: CASENT0133665 , CASENT0133713 ; CASC: CASENT0133661 , CASENT0133677 , CASENT0133678 , CASENT0133705 , CASENT0133710 , CASENT0133715 ; MHNG: CASENT0133674 , CASENT0133708 ); (1 minor worker) , Mont Chongui, 12.95945 S, 45.1341 E, 380 m, rainforest, on low vegetation, collection code BLF18897, 28.xi.2007 (B.L. Fisher et al.) ( CASC: CASENT0132583 ); (1 minor worker) , Mont Chongui, 12.996 S, 45.1343 E, 550 m, rainforest, sifted leaf litter, collection code BLF18860, 28.xi.2007 (B.L. Fisher et al.) ( CASC: CASENT0125677 ) .

Diagnosis: Moderately small species (WL major 0.95–1.12 mm, WL minor 0.57–0.86 mm), minor and major workers with moderately short scapes and legs (SI major 46–57, FI major 64–78, SI minor 107–130, FI minor 102– 134); postpetiole of both worker subcastes with moderately large, often anteriorly situated, ventral process, propodeal spines often very short, promesonotal process absent or inconspicuous, standing hairs relatively fine, acute, and abundant, with many shorter hairs in between. Major head anteriorly longitudinally rugose and posterior 2/5 smooth and shiny (as in P. megacephala ), postpetiole on average about 1.7 times wider than petiole (PpWI 155–183). Minor worker face and promesonotal dorsum smooth and shiny, head about 1.1 times longer than wide (CI 87–94), postpetiole on average about 0.7 times as long as petiole (PpLI 58–79).

Description of major workers: Measurements (holotype): HW 1.29, HL 1.36, SL 0.66, MDL 0.73, EL 0.16, WL 1.02, PNH 0.43, PNW 0.61, MNH 0.67, PDH 0.35, PTL 0.38, PPL 0.24, PTH 0.23, PPH 0.25, PTW 0.17, PPW 0.28, PSL 0.14, MFL 0.87, MTL 0.65, CI 95, SI 51, MDI 57, EI 12, FI 67, PSLI 11, LPpI 96, DPpI 117, PpWI 165, PpLI 63, PpHI 109.

Measurements (n=13): HW 1.12–1.44 (1.31), HL 1.10–1.44 (1.31), SL 0.60–0.74 (0.67), MDL 0.58–0.84 (0.71), EL 0.15–0.19 (0.17), WL 0.95–1.12 (1.05), PNH 0.38–0.47 (0.43), PNW 0.58–0.69 (0.63), MNH 0.64–0.75 (0.70), PDH 0.31–0.40 (0.36), PTL 0.33–0.44 (0.39), PPL 0.23–0.28 (0.26), PTH 0.22–0.26 (0.24), PPH 0.24–0.29 (0.27), PTW 0.18–0.22 (0.20), PPW 0.28–0.37 (0.33), PSL 0.13–0.21 (0.16), MFL 0.81–0.90 (0.86), MTL 0.59– 0.78 (0.67), CI 96–103 (100), SI 46–57 (52), MDI 48–60 (54), EI 11–15 (13), FI 64–78 (70), PSLI 11–16 (12), LPpI 85–108 (97), DPpI 115–148 (127), PpWI 155–183 (166), PpLI 56–77 (67), PpHI 104–114 (110).

Head about as long as wide (CI 95–103), usually heart shaped, with convex sides and posterior emargination relatively deep (as in P. megacephala ). Mandibles smooth and shiny and of moderate length (MDI 48–60), clypeus smooth with weak to superficial median and lateral carinae. Frons and sides of head anteriorly longitudinally rugose, interspaces superficially to weakly punctate. Posterior 2/5 of face, behind level where scapes end when laid back, smooth and shiny, but sometimes medially with irregular weak rugulae extending to posterior margin. Frontal carinae short to moderately short, antennal scrobe absent to inconspicuous. Scapes of medium length (SI 46–57) with decumbent to subdecumbent pilosity and few longer suberect to erect hairs along outer edge. Submedian hypostomal teeth very small to inconspicuous, median process absent. Promesonotum convex in profile, without prominent promesonotal process, posterior declivity often weakly marginate anteriorly (at posterior end of pronotum), oblique and angulate at its lower portion, humeri not laterally produced in dorsal view. Dorsum of promesonotum smooth or superficially punctate and usually with weak to superficial irregular transverse rugulae, lateropronotum weakly to superficially punctate, anteriorly weakly rugulose and medially smooth, remainder of mesosoma densely and finely punctate. Metanotal groove barely or not impressed, cross-ribs superficially developed. Spines moderately short and acute (PSI 11–16), shorter than the distance between their bases. Metafemur relatively short (FI 64–78), metatibia on inner edge with decumbent pilosity, on outer edge with decumbent to suberect pilosity. Postpetiole on average almost as high as long (LPpI 85–108), in profile with a weakly rounded to subacute, anteriorly directed, ventral process, in dorsal view trapezoidal, about 1.7 times wider than petiole (PpWI 155–183). Dorsum of petiole and postpetiole smooth to superficially punctate, remainder punctate. Gaster smooth. Standing hairs on dorsal surfaces abundant, relatively long, acute, with abundant, decumbent to suberect, shorter pilosity in between. Color orange to reddish brown, gaster often darker.

Description of minor workers: Measurements (n=21): HW 0.44–0.67 (0.56), HL 0.49–0.73 (0.62), SL 0.49– 0.74 (0.66), MDL 0.24–0.41 (0.36), EL 0.10–0.13 (0.12), WL 0.57–0.86 (0.74), PNH 0.20–0.31 (0.26), PNW 0.28–0.43 (0.36), MNH 0.37–0.54 (0.47), PDH 0.18–0.29 (0.24), PTL 0.20–0.35 (0.26), PPL 0.14–0.21 (0.18), PTH 0.12–0.17 (0.15), PPH 0.13–0.21 (0.17), PTW 0.08–0.12 (0.10), PPW 0.12–0.22 (0.18), PSL 0.05–0.09 (0.08), MFL 0.49–0.80 (0.67), MTL 0.36–0.60 (0.51), CI 87–94 (91), SI 107–130 (117), MDI 52–70 (64), EI 19– 23 (21), FI 102–134 (119), PSLI 11–16 (13), LPpI 90–133 (108), DPpI 88–117 (100), PpWI 155–191 (173), PpLI 58–79 (71), PpHI 100–133 (116).

Head shape ovoid, slightly longer than wide (CI 87–94), posteriorly slightly compressed with head margin almost straight, sides convex, posterior head margin moderately to relatively wide with rounded lateral corners, medially concave, occipital carina very narrow, almost invisible in full-face view. Mandibles relatively short (MDI 52–70) and smooth, except for faint rugulation laterobasally. Clypeus and rest of face mostly smooth, clypeal carinae absent. Few concentric rugulae around antennal insertion present, with few additional longitudinal rugulae toward posterior margin of eyes. Scapes moderately long (SI 107–130), when laid back surpassing posterior head margin at least by length of tenth funicular segment, with relatively coarse, suberect to erect pilosity. Promesonotal outline in lateral view roundly convex, declining evenly from highest point toward very shallowly impressed metanotal groove, posterior process absent. Propodeum in profile about as long as high, with dorsum slightly convex. Propodeal spines often very short and reduced, much shorter than distance between their bases, subtriangular and acute (PSLI 11–16, mean 13). Pronotum smooth dorsally and laterally except superficial punctures anteriorly near the neck, mesonotum smooth dorsally, mesopleuron and propodeum punctate, sometimes superficially punctate around propodeal spiracle. Metafemur short (FI 102–134), metatibia with coarse subdecumbent to suberect pilosity and some longer suberect hairs on outer edge. Postpetiole in profile with moderately large ventral process anteriorly, on average 1.1 times longer than high (LPpI 90–133), and 0.7 times as long as petiole (PpLI 58–79). Petiole and postpetiole dorsally smooth, remainder weakly to superficially punctate. Gaster smooth and shiny. Standing hairs abundant to sometimes very abundant, slender, whitish, acute, with several longer and many shorter hairs dorsally on head, pronotum, postpetiole, and gaster. Color orange to completely brown with gaster often slightly darker.

Discussion: Pheidole decepticon is a relatively widespread megacephala group species on the islands neighboring Madagascar. It occurs on the Comoros (Anjouan Island), Mayotte, Juan de Nova Island, and on the Cosmoledo Atoll of the Seychelles, which is located about 415 km northeast of Mayotte. Morphologically very similar to P. megacephala and P. megatron , the three are the only megacephala group species currently encountered on the smaller islands. Other species, such as the previously reported P. punctulata , were not collected recently on any of the islands. On Anjouan Island P. decepticon occurs together with P. megacephala and P. megatron . The latter was collected in lowland dry forest, coastal scrub land, and in a coconut plantation, while P. decepticon was found in rainforest, lowland coastal forest, Casuarina forest, old settlements, coral karst scrubland, and along roadsides. Pheidole megacephala was not found in forested habitats on Anjouan, but was collected once from within a coastal village. Whether the other two species occur in direct sympatry, or if they are spatially or ecologically separated is not known. The minor and major workers of P. decepticon are best separated from those of the other two species by their standing hairs, which are more abundant, fine and acute compared to the more sparsely distributed standing hairs that often end in blunt or bifurcate apices in P. megacephala and P. megatron . In addition, the postpetiolar ventral process of the major workers is less roundly convex and slightly smaller in the P. decepticon specimens (see also under discussion of P. megatron & P. megacephala ).

Etymology: This new species is named after the nefarious alien robot warriors called Decepticons, who are the antagonists of the Autobots in the famous Transformers universe. The name is a noun in apposition and thus invariable.

Additional material examined: COMOROS: Anjouan: 12.1877 S, 44.3593 E, 65 m, coastal roadside, 26.i.2009 (B.L. Fisher et al.); 12.2576 S, 44.3891 E, 20 m, along roadside, 27.i.2009 (B.L. Fisher et al.); JUAN DE NOVA ISLAND: 17.0487 S, 42.7101 E, 10 m, littoral vegetation, 11.iv.2011 (B.L. Fisher et al.); 17.0527 S, 42.7163 E, 12 m, sandy trail in Casuarina forest, 11.iv.2011 (B.L. Fisher et al.); 17.0618 S, 42.7251 E, 5 m, scrub on coastal karst, 12.iv.2011 (B.L. Fisher et al.); 17.0605 S, 42.7243 E, 12 m, Casuarina forest, 12.iv.2011 (B.L. Fisher et al.); 17.0518 S, 42.7265 E, 10m, old settlement, 13.iv.2011 (B.L. Fisher et al.); Trail to Trou bleu, 17.0531 S, 42.7341 E, Bord de sentier, 30.vii.2007 (G. Cazanove); MAYOTTE: Mont Combani , 12.8063 S, 45.1531 E, 370 m, rainforest, 25.xi.2007 (B.L. Fisher et al.); Tanaraki , 12.7575 S, 45.0678 E, 10 m, coastal scrub, 26.xi.2007 (B.L. Fisher et al.); Dapani , 12.9749 S, 45.1618 E, 1 m, mangrove, coastal scrub, 27.xi.2007 (B.L. Fisher et al.); Mont Chongui summit, 12.9957 S, 45.1343 E, 550 m, rainforest, 28.xi.2007 (B.L. Fisher et al.); Rèserve Forestière Sohoa , 12.8059 S, 45.1005 E, coastal scrub, rainforest, 29.xi.2007 (B.L. Fisher et al.); Mont Benara , 12.8758 S, 45.1567 E, 425 m, rainforest, 30.xi.2007 (B.L. Fisher et al.); Rèserve Forestière Sohoa, 12.8124 S, 45.1048 E, 10 m, coastal dry forest, 01.xii.2007 (B.L. Fisher et al.); Dapani, 12.9628 S, 45.1504 E, 135 m, rainforest, 02.xii.2007 (B.L. Fisher et al.); Rèserve Forestière Majimbini , 12.7689 S, 45.1902 E, 350 m, rainforest, 03.xii.2007 (B.L. Fisher et al.); Petite Terre , 12.7912S, 45.294 E, 125 m, coastal scrub, 04.xii.2007 (B.L. Fisher et al.); Mlima Choungi , near crossroad GRMT1 & CCT11, forest, 19.vii.1998 (R. Jocque); Petite Terre, Dziani Dzaha , 12.7833 S, 45.1167 E, 19.ii.1999 (R. Jocque & G. DeSmet); Mt. Benara , track to reserve gate, 12.8667 S, 45.1833 E, 250 m / 270 m, 23.ii.1999 (R. Jocque & G. DeSmet); Mt. Benara , 12.8667 S, 45.1833 E, 630 m, forest litter, 23.ii.1999 (R. Jocque & G. DeSmet); Sazile , 12.9667 S, 45.1667 E, dry forest litter, 26.ii.1999 (R. Jocque & G. DeSmet); Coconi, SDA ( Service du Développement Agricole ), 12.8333 S, 45.1333 E, wet area with giant bamboo, 18.ii.1999 (R. Jocque & G. DeSmet); Mt. Chongui , 12.8 S, 45.1 E, 360 m, forest near fallen tree, 15.ii.1999 (R. Jocque & G. DeSmet); Dziani Karihani , 12.7833 S, 45.1167 E, forest, 14.ii.1999 (R. Jocque & G. DeSmet); Sada , 12.7786 S, 45.1403 E, in house, 3.iii.1999 (M. Charleux); Tsingoni , 12.7833 S, 45.1 E, litter of shrubs on mangrove edge, 27.ii.1999 (R. Jocque & G. DeSmet); SEYCHELLES: Cosmoledo Atoll ( Wizard Island ): on dune, grass, 9.75611 S, 47.6467 E, 10 m, lowland coastal, coralline island, 21.xi.2011 (G. Galman).

Figures

FIGURE 15 Pheidole decepticon sp. n., full-face view (A), profile (B), and dorsal view (C) of paratype minor worker (CASENT0133677) and full-face view (D), profile (E), and dorsal view (F) of holotype major worker (CASENT0132558).