Pheidole, Westwood

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 : 307-313

Synopsis of Pheidole species in the Southwest Indian Ocean islands

braueri Forel, 1897

decepticon Fischer & Fisher sp. n.

dodo Fischer & Fisher sp. n.

fervens Smith, F., 1858 = pungens Smith, 1861 = javana Mayr, 1867 = cavannae Emery, 1887 = javana var. dharmsalana Forel, 1902 = amia Forel, 1912 = javana var. dolenda Forel, 1912 = oceanica subsp. nigriscapa Santschi, 1928 = oceanic subsp. nigriscapa var. tahitiana Cheesman & Crawley, 1928 = javana var. desucta Wheeler, 1929 = javana var. soror Santschi, 1937b = nodus st. azumai Santschi, 1941

jonas Forel, 1907

komori Fischer & Fisher sp. n.

loki Fischer & Fisher sp. n.

megacephala (Fabricius), 1973 = edax Forskål, 1775 = trinodis Losana, 1834 = pusilla Heer, 1852 = janus Smith, 1858 = laevigata Smith, 1855 = laevigata Mayr, 1862 = agilis Smith, F., 1857 = testacea Smith, F. 1858 = perniciosa Gerstäcker, 1859 = suspiciosa Smith, F., 1859 = megacephala r. scabrior Forel, 1891 syn. n. = picata Forel, 1891 syn. n. = punctulata r. gietleni Forel, 1905 syn. n. = picata var. bernhardae Emery, 1915 syn. n.

megatron Fischer & Fisher sp. n.

parva Mayr, 1865 = parva var. decanica Forel, 1902 = flavens var. farquharensis Forel, 1907 syn. n. = sauteri Wheeler, 1909 = rinae var. mala Forel, 1911 = rinae r. tipuna Forel, 1912 = bugi Wheeler, 1919 = tardus Donisthorpe, 1947 syn. n.

ragnax Fischer & Fisher sp. n.

teneriffana Forel, 1893 = voeltzkowii Forel, 1894 syn. n. = teneriffana subsp. taina Aguayo, 1932

vulcan Fischer & Fisher sp. n.

Key to Pheidole species in the islands of the Southwest Indian Ocean (minor and major workers)

1a. Minors & majors: Relatively large species (WL minors 0.76–1.07, WL majors 1.06–1.65), with scapes and legs moderately long to very long (SI minors 120–209, FI minors 134–226, FL majors 1.01–168) and promesonotal process well-developed, angulate to subangulate, with a relatively deep angular groove in lateral view ( Fig. 2A,B )............................ 2

1b. Minors & majors: Mostly smaller species (WL minors 0.51–0.84, WL majors 0.70–1.22), with scapes and legs usually shorter (SI minors 85–130, FI minors 91–135, FL majors 0.55–1.06) and promesonotal process absent ( Fig. 2C ), or if present in major workers then the transverse groove in profile view at most shallowly concave ( Fig. 2D )....................... 5

2a. Minors: Postpetiole with convex ventral process ( Fig. 3A ). Majors: Head significantly longer than wide (CI 82–88). Posterior half of face lacking longitudinal rugae ( Fig. 3B ). Submedian hypostomal teeth moderately large. Postpetiole with small acute ventral process. Comoros Is., Mozambique.......................................................... P.komori

2b. Minors: Postpetiole without ventral process ( Fig. 3C ). Majors: Head about as wide as long (CI 93–101). Face with longitudinal to posteriorly oblique rugae reaching toward posterolateral corners ( Fig. 3D ). Submedian hypostomal teeth small or inconspicuous. Postpetiole without ventral process................................................................ 3

3a. Minors: Head almost 50% longer than wide (CI 67–72) with raised occipital carina ( Fig. 4A ), metafemur very long, more than twice as long as head width (FI 209–226). Majors: Frontal carinae and antennal scrobe absent or inconspicuous ( Fig. 4B ), legs comparatively long (FI 99). Mayotte............................................................... P. ragnax

3b. Minors: Head relatively shorter (CI 72–88) and without raised occipital carina ( Fig. 4C ), metafemur shorter (FI 134–170). Majors: Frontal carinae and antennal scrobe present and conspicuous ( Fig. 4D ), legs shorter (FI 73–91)................. 4

4a. Minors: Scape and metatibia pilosity mostly subdecumbent to suberect ( Fig. 5A ), metanotal groove in profile well-impressed ( Fig. 5B ), eyes moderately large (mean EI 22), and propodeal spines relatively short (mean PSLI: 12). Majors: Frontal carinae reaching at least 4/5 of the distance to posterior head margin, scrobe area and sides of head punctate to weakly punctate, in fullface view with coarse suberect hairs laterally ( Fig. 5C ). ( Mauritius) widespread, introduced species..... P. fervens Smith, F.

4b. Minors: Scape and metatibia pilosity decumbent to subdecumbent, plus longer suberect hairs along outer edge ( Fig. 5D ), metanotal groove not or barely impressed in profile ( Fig. 5E ), eyes slightly larger (mean EI 28), and spines relatively longer (mean PSLI: 16). Majors: Frontal carinae reaching ¾ of the distance to posterior head margin, scrobe area and sides of head superficially punctate, in full-face view with decumbent to subdecumbent hairs laterally ( Fig. 5F ). ( Comoros Is., Madagascar, Mauritius, Mayotte, Seychelles) widespread, introduced species.................................. P. teneriffana Forel

5a. Minors & majors: Postpetiole in profile with large to moderately large, usually convex, ventral process ( Fig. 6A ), in some major workers widely subtriangular, but never acute ( Fig. 6B ), and postpetiole almost always higher than petiole (PpHI minors 100–146, PpHI majors 104–123). Minors: Face entirely smooth and shiny and scapes moderately short (SI 107–130), head shape oval, posterior head margin in full-face view rounded to medially straight ( Fig. 6C ), promesonotum in profile roundly convex: Majors: Submedian hypostomal teeth always small to inconspicuous and median process absent................ 6

5b. Minors & majors: Postpetiolar ventral process absent ( Fig. 6D ), or if present in major workers, then small and acute ( Fig. 6E ), never convex or broadly triangular in profile, and postpetiole usually lower than petiole, only very rarely higher in major workers (PpHI minors 73–97, PpHI majors 79–106). Minors: Face usually punctate, if face entirely smooth and shiny then head shape posteriorly more broadly transverse and scapes shorter (SI 91–98) ( Fig. 6F ), promesonotum in profile flatly convex and elongate. Majors: Submedian hypostomal teeth never small to inconspicuous, but relatively large, median process present or absent............................................................................................... 8

6a. Minors: Standing hairs relatively fine and acute, abundant, and with several shorter hairs between longer pilosity ( Fig. 7A ). Majors: Postpetiolar ventral process slightly angulate to subtriangular in profile and small to moderately large, not convex, standing hairs relatively fine and acute ( Fig. 7B ). Comoros Is., Juan de Nova Is., Mayotte, Seychelles......... P. decepticon

6b. Minors: Standing hairs relatively thicker, often blunt or bifurcate apically, and usually less abundant, with few or almost no shorter hairs between longer pilosity ( Fig. 7C ). Majors: Postpetiolar ventral process larger and convex, standing hairs thicker ( Fig. 7D ), often blunt or apically bifurcate................................................................. 7

7a. Minors: Head about 0.9 times as wide as long (CI 86–92) and postpetiole about 0.8 times the length of petiole (PpLI 70–91) ( Fig. 8A ). Majors: Head usually heart shaped with posterior emargination moderately deep, sides of head strongly convex, posterior 1/3 to 1/4 of face, behind level where scapes end, smooth and shiny except for weak median rugae ( Fig. 8B ), posterolateral corners of head in profile ventrally smooth and shiny, at most with microsculpture present ( Fig. 8C ). ( Comoros, Juan de Nova Is., Madagascar, Mauritius, Mayotte, Réunion, Seychelles) globally introduced species.. P. megacephala (Fabricius)

7b. Minors: Head slightly narrower (CI 82–87) and postpetiole shorter, about 0.7 times the length of petiole (PpLI 63–71) ( Fig. 8D ). Majors: Head less heart shaped, with posterior emargination relatively shallow ( Fig. 8E ), posterior 1/3 to 1/4 of head not completely smooth and shiny, some specimens superficially punctate, and some specimens with few to several, short, irregular, longitudinal rugulae, posterolateral corners of head in profile ventrally with punctate to weakly punctate sculpture ( Fig. 8F ). Comoros Is................................................................................. P. megatron

8a. Minors: Face smooth ( Fig. 9A ) to medially superficially punctate and laterally punctate to weakly punctate, with scape pilosity mostly suberect ( Fig. 9B ), and eyes relatively large (EI 22–24, mean 24). Majors: Frontal carinae strongly developed and laterally extended, obscuring part of antennal scrobe ( Fig. 9C ). Seychelles............................ P. braueri Forel

8b. Minors: Either face mostly punctate to strongly punctate, sometimes overlain with faint rugulae ( Fig. 9D ), or face sculpture more reduced, then scape pilosity decumbent to subdecumbent ( Fig. 9E ) and eyes slightly smaller ( P. dodo: EI 18–22, mean 21). Majors: Frontal carinae absent or short and inconspicuous, never laterally extended and obscuring part of antennal scrobe ( Fig. 9F )............................................................................................. 9

9a. Minors: Postpetiole usually about as long as high (LPpI 91–115, mean 102) and pronotum laterally mostly smooth and shiny ( Fig. 10A ). Majors: Posterior portion of face and of posterolateral lobes smooth and shiny, without rugae or punctures ( Fig. 10B ). Mauritius.................................................................................. P. dodo

9b. Minors: Either postpetiole longer than high (LPpI 114–163) ( Fig. 10C ) or pronotum laterally not mostly smooth and shiny ( Fig. 10D ). Majors: Face and posterolateral lobes never partly smooth and shiny, but rugoreticulate and punctate to superficially punctate ( Fig. 10E ).............................................................................. 10

10a. Minors: Postpetiole distinctly higher than long (LPpI 83–95) ( Fig. 11A ) and on average 1.4 times wider than long (DpPI 125– 150) ( Fig. 11B ). Majors: Head distinctly longer than wide (CI 88–93) ( Fig. 11C ). ( Mauritius, Seychelles, Saudi Arabia, United Arab Emirates) widespread, probably introduced species........................................... P. parva Mayr

10b. Minors: Postpetiole at least as long as high or longer (LPpI 114–163) ( Fig. 11D ) and on average about as wide as long (DpPI 86–109) ( Fig. 11E ). Majors: Head about as long as wide (CI 95–102) ( Fig. 11F ).................................. 11

11a. Minors (major unknown): Head posteriorly superficially punctate to smooth, mesosoma sculpture reduced, mostly very faintly punctate ( Fig. 12B ), sometimes overlain with superficial rugulae, scapes longer, on average 1.2 times longer than width of head (SI 117–122) and postpetiole significantly longer than wide (DPpI 86) ( Fig. 12B ). Mayotte................... P. loki

11b. Minors: Head and majority of mesosoma both uniformly punctate to weakly punctate, promesonotum sometimes overlain with transverse rugulae ( Fig. 12A ), scapes on average 1.0 to 1.1 times longer than width of head (SI 96–122), and postpetiole on average as long as wide (DPpI 88–109) ( Fig. 12A ). Majors: Promesonotum dorsally with transverse rugulae, posterior process in profile weakly defined with inconspicuous to shallowly concave transverse groove, postpetiole in dorsal view with large lateral process.................................................................................. 12

12a. Minors: Mandibles and scapes relatively short (MDI 54–63, SI 96–106), postpetiole about 1.2 times longer than high (LPpI 114–120), standing hairs on mesosoma abundant ( Fig. 13A ). Majors: Promesonotal process high in profile view, with weakly impressed transverse groove, propodeal spines relatively long and spinose (PSLI 14–17), postpetiole higher than long (LPpI 83–95), and standing hairs on mesosoma abundant, relatively flexuous ( Fig. 13B ). Comoros Is.................. P. vulcan

12b. Minors: Mandibles and scapes slightly longer (MDI 60–73, SI 102–122), postpetiole about 1.4 times longer than high (LPpI 122–163), standing hairs on mesosoma comparatively scarce ( Fig. 13C ). Majors: Promesonotal process lower, with a more concavely impressed groove, propodeal spines shorter and subtriangular (PSLI 10–14), postpetiole usually longer than high (LPpI 90–126), and standing hairs less abundant and less flexuous ( Fig. 13D ). Comoros Is., Mayotte......... P. jonas Forel

Figures

FIGURE 2 Pheidole teneriffana, profile of minor (CASENT0280996) (A) and major worker (CASENT0189743) (B); P. decepticon, profile of minor worker (CASENT0133677) (C); P.vulcan, profile of major worker (CASENT0137234) (D).

FIGURE 3 Pheidole komori, profile of minor (CASENT0149121) (A) and full-face view of major worker (CASENT0147188) (B); P. teneriffana, profile of minor worker (CASENT0280996) (C); P. ragnax, full-face view of major worker (CASENT0132467) (D).

FIGURE 4 Pheidole ragnax, full-face views of minor (CASENT0132467) (A) and major worker (CASENT0136791) (B); P. teneriffana, full-face view of minor worker (CASENT0280996) (C); P. fervens, full-face view of major worker (CASENT0060250) (D).

FIGURE 5 Pheidole fervens, dorsal view of scape (A) and profile (B) of minor (CASENT006581), and full-face view of major worker (CASENT0060250) (C); P. teneriffana, dorsal view of scape (D) and profile (E) of minor worker (CASENT0280996) and full-face view of major worker (CASENT0189743) (F).

FIGURE 6 Pheidole megacephala, full-face view (A) and profile (B) of minor (CASENT0056016) and full-face view of major worker (CASENT0104990) (C); P. braueri, full-face view of minor worker (CASENT0101571) (D); P. dodo, profile of minor worker (CASENT0060619) (E); P.vulcan, full-face view (F) and profile (G) of major worker (CASENT0060617).

FIGURE 7 Pheidole decepticon, profile of minor (CASENT0133677) (A) and major worker (CASENT0132558) (B); P. megacephala, profile of minor (CASENT0056016) (C) and major worker (CASENT0104990) (D).

FIGURE 8 Pheidole megacephala, profile of minor (CASENT0056016) (A), full-face view (B) and profile (C) of major worker (CASENT0104990); P. megatron, profile of minor (CASENT0281179) (D), full-face view (E) and profile (F) of major worker (CASENT0147194).

FIGURE 9 Pheidole braueri, full-face view of syntype minor (CASENT0101571) (A), non-type minor (CASENT0159919) (B), and of major worker (CASENT0217235) (C); P.parva, full-face view of minor worker (CASENT0160528) (D); P. dodo, full-face view of minor worker (CASENT0060619) (E); P.vulcan, full-face view of major worker (CASENT0137234) (F).

FIGURE 10 Pheidole dodo, profile of minor (CASENT0060619) (A) and full-face view of major worker (CASENT0060617) (B); P.vulcan, profile of minor worker (CASENT0137429) (C); P.parva, profile of minor worker (CASENT0160279) (D); P. vulcan, full-face view of major worker (CASENT0137234) (E).

FIGURE 11 Pheidole parva, profile (A) and dorsal view (B) of minor (CASENT0160279) and full-face view of major worker (CASENT0160280) (C); P. vulcan, profile (D) and dorsal view (E) of minor (CASENT0137429) and full-face view of major worker (CASENT0137234) (F).

FIGURE 12 Pheidole vulcan, dorsal view of minor worker (CASENT0137429) (A); P. loki, dorsal view of minor worker (CASENT0059150) (B).

FIGURE 13 Pheidole vulcan, profile of minor (CASENT0137429) (A) and major worker (CASENT0137234) (B); P. jonas, profile of minor (CASENT0137429) (C) and major worker (CASENT0146984) (D).