Color usually dull yellow to dull brownish yellow. MajorHW 0.83–1.05, HL 0.90–1.11, SL 0.49–0.62, CI 88–98, SI 50–61 (n=43, Longino pers. comm.). Head uniform in color (Fig. 35); subquadrate (Fig. 7); often entirely punctate (Fig. 11), but portions of posterolateral lobes can be glossy. Posterolateral lobes never with distinct rugae. Promesonotum in profile forming a single dome (Fig. 4). Postpetiole not swollen relative to petiole (Fig. 3). Postpetiole relatively broad; distinctly more than 2× petiolar width in dorsal view (Fig. 31). First gastral tergite with anterior third to entire surface matte. MinorHW 0.38–0.50, HL 0.44–0.59, SL 0.44–0.58, CI 82–90, SI 106–120 (n=49, Longino pers. comm.). Head dull, entirely covered by reticulated network of punctures (Fig. 37). Posterior head margin relatively narrow and rounded (Fig. 58). Antennal scapes lack standing hairs (Fig. 55); scapes surpass posterior head margin by a distance equal to or greater than eye (Fig. 40). Promesonotum in profile forming a single dome (Fig. 42), lacking a distinct mound or prominence on the posterior slope. Hairs on mesosoma stout, stiff, of equal length and arranged in pairs (Fig. 53). Postpetiole narrow in dorsal view, only slightly broader than petiole. Gaster with at least anterior 1/3 of first tergite matte (Fig. 33).

Pheidole anastasii, P. bilimeki and P. punctatissima all belong to the P. punctatissima clade (Economo et al. 2015). These ants are all relatively small species characterized by densely punctate ground sculpture that gives them a dull, matte appearance. Among species treated here, the P. punctatissima clade species are most easily confused with those of the closely related P. flavens complex. Major and minor workers are most reliably diagnosed from those of the P. flavens complex by the relatively broad postpetiole (Fig. 31, major; Fig. 62, minor) and the matte anterior portion of the gaster (Fig. 33) in addition to other characters listed in the key. The minor workers can also be confused with those of Asian native P. parva, but can be distinguished by the more uniform and stout mesosomal hairs (Fig. 53), and by the antennal scapes which lack erect hairs (Fig. 55) and tend to surpass the posterior head margin by a distance equal to or greater than eye (Fig. 40). In the Neotropics, there are many native species that closely resemble P. anastasii (Wilson 2003), and identification of the minor worker subcaste is especially challenging.

Among introduced members of the clade, the major workers of P. punctatissima are immediately distinguished from those of both P. anastasii and P. bilimeki by the bicolored head (Fig. 33). The minor workers of P. punctatissima tend to have narrower posterior head margins and longer antennal scapes than those of P. anastasii and P. bilimeki. Separating P. anastasii from P. bilimeki is particularly difficult. They are most reliably distinguished by ecological characteristics, with the former preferring to nest arboreally and the latter preferring to nest under stones or in dead wood. The morphological characters separating these two species are highly variable, but the major workers of P. anastasii tend more often towards yellow (versus tending towards brown in P. bilimeki) and can have relatively wider heads (HW 0.74–1.16 mm vs. 0.71–1.07 mm). The minor workers of P. anastasii tend to have more narrow heads posteriorly then P. bilimeki (Fig. 58 vs. Fig. 57) and relatively longer scapes (SI 103–125 vs. 95–108). See Longino and Cox (2009) for additional details.

Adding to the already confusing taxonomy separating P. anastasii and P. bilimeki is the widespread application of the name P. floridana Emery to populations across the southern United States. The first record of P. floridana from Florida was the type series described by Emery from Coconut Grove (Miami area) in 1895. Smith (1930) recorded P. floridana in his original list of Florida ants, and added P. anastasii three years later (1933), stating only “This species [P. anastasii], which was originally described from Costa Rica, is recorded here for Florida on the basis of information secured from Dr. Wheeler…I have seen the same species in greenhouses in the District of Columbia, New Jersey, and Illinois.” The previous year (1932) Wheeler, who had received type material of P. floridana from Emery (Wheeler 1908c), included P. floridana and P. anastasii in his own list of Florida ants.

Naves (1985) in his study of Florida Pheidole, also recognized both species and distinguished P. anastasii from P. floridana by the matte base of the gaster in the former and the glossy gaster in the latter. Indeed, the type specimens of P. floridana from Coconut Grove are consistent with this characterization (CASENT0904424, CASENT0904425). Naves wrote that the Miami area was the only place where he was able to locate P. floridana. Pheidole anastasii, in contrast, was reported by Naves as widely distributed across the state.

Deyrup et al. (1988), lamenting the taxonomic confusion surrounding P. floridana, P. flavens and P. anastasii in Florida, stated, “Traditionally (Creighton 1950; Smith 1979) the name P. floridana has been applied to a widespread upland species that has a distinctive matte area on the base of the first gastral tergite and very evenly rugose head…This is the species we report from the Keys [Florida].” Subsequent reviews of Florida ants have thus excluded P. anastasii from their lists (Deyrup 2003; Deyrup et al. 2000; Moreau et al. 2014). Wilson (2003) followed Deyrup in treating all outdoor populations from the United States as P. floridana, but conceded that his concept of P. floridana could represent a northern geographic variant of P. bilimeki or an endemic species modified by intergradation with a P. bilimeki immigrant population.

With respect to all outdoor North American records, we follow Wheeler (1932), Smith (1933), and Naves (1985) in treating the localized glossy-gaster P. floridana as distinct from the widespread matte-gaster species referred to as P. anastasii by the aforementioned authors. However, the relatively short scapes and posteriorly broad heads of the minor workers, together with the habitat and nesting preferences of the matte-gaster species suggests the name P. bilimeki Mayr more accurately applies to this widespread taxon than does P. anastasii Emery. The issue is discussed in further detail under the P. bilimeki section.

Pheidole anastasii, named by Emery on behalf of Sig. Anastasio Alfaro, is a Neotropical species that is occasionally found indoors beyond its native range. Although at least some arboreal colonies appear to be polydomous, P. anastasii is a low-impact adventive that has thus far shown little capacity for becoming a significant invader. The biology of P. anastasii, especially across its native range in Costa Rica and in comparison to P. bilimeki was reviewed by Longino and Cox (2009). The species was noted as being among the most abundant ants in the low arboreal forest understory of La Selva Biological Station (Costa Rica). Although tolerant of disturbance, P. anastasii requires some vegetation cover and does not occur in open areas. All collections reviewed by Longino and Cox were from wet forest habitats. Most were from below 500 m elevation, but several ranged to a maximum of 1200 m. The propensity for the species to be inadvertently transported to greenhouses across the world is predicted by its arboreal foraging and nesting habits. Longino and Cox (2009) observed the species nests in almost any kind of cavity or sheltered space, including live stems, and that workers often build galleries and tunnels with carton or earthen construction. The species was reported to occur in lowland second growth, evergreen forest, coffee plantation, limestone, ravine, mixed hardwood-pine forest, wet forest, on karst, and cloud forest. It was also reported to nest in dead sticks and branches on or above the forest floor, under bark flaps on tree trunks, beneath epiphytes and under stones.

Pheidole anastasii is a Neotropical native that ranges from Mexico to southern Central America or northern South America. We consider many of the outdoor records of P. anastasii from the southern United States to refer instead to P. bilimeki (see discussion above). There are, however confirmed records of the species from heated indoor locations – especially greenhouses. In North America there are records from hothouses in Washington D.C. and New York (Longino and Cox 2009), and also from Massachusetts. In Europe, the Netherlands occurrences reported as P. anastasii by Boer and Vierbergen (2008) refer to P. bilimeki (Boer, pers. comm.). The records from Denmark and Norway might also refer to P. bilimeki, but until specimens can be examined we follow the authors’ use of P. anastasii (Birkemoe and Aak 2008; Lomholdt 1986).

Pheidole anastasii is a synanthropic species with a high tolerance for habitat disturbance. It is occasionally found in human habitations and in greenhouses. There is little indication that is causes significant impact to agricultural systems or native ecosystems. The species is a quarantine risk, and is thought to be transported with fresh plant material.

Color usually red brown, rarely yellow brown. MajorHW 0.75–1.04, HL 0.79–1.13, SL 0.44–0.57, CI 87–97, SI 50–65 (n=39, Longino pers. comm.). Head uniform in color (Fig. 35); subquadrate (Fig. 7); often entirely punctate (Fig. 11), but portions of posterolateral lobes can be glossy. Posterolateral lobes never with distinct rugulae. Promesonotum in profile forming a single dome (Fig. 4). Postpetiole not swollen relative to petiole (Fig. 3). Postpetiole relatively broad; distinctly more than 2× petiolar width in dorsal view (Fig. 31). First gastral tergite with anterior third to entire surface matte. MinorHW 0.42–0.52, HL 0.47–0.59, SL 0.40–0.54, CI 83–93, SI 88–108 (n=38, Longino pers. comm.). Head, including the area mesad of the frontal carinae, entirely covered by reticulated network of punctures, giving it a dull appearance (Fig. 37). Posterior head margin relatively broad and flat (Fig. 57). Antennal scapes lack standing hairs (Fig. 55); surpass posterior head margin by a distance equal to or greater than eye (Fig. 40). Promesonotum in profile forming a single dome (Fig. 42), lacking a distinct mound or prominence on the posterior slope. Hairs on mesosoma stout, stiff, of equal length and arranged in pairs (Fig. 53). Postpetiole narrow in dorsal view, only slightly broader than petiole. Gaster with at least anterior 1/3 of first tergite matte (Fig. 33).

Pheidole bilimeki is a member of the Neotropical P. punctatissima clade, together with P. anastasii and P. punctatissima (Economo et al. 2015). Among species treated here, it is easily confused with the aforementioned and members of the P. flavens complex. Minor workers can also be confused with those of P. parva. See section under P. anastasii for identification notes. In the southeastern United States, P. bilimeki is often confused with P. floridana Emery, which is discussed in more detail below. In the Neotropics, there are many native species that closely resemble P. bilimeki (Wilson 2003).

We propose the synonymy of P. lauta Wheeler to be transferred from P. floridana to P. bilimeki. In his original description Wheeler (1908c) wrote, “…the worker has the base of the gaster opaque whereas this is shining in the specimen of floridana given me by Prof. Emery.” The description and the photographs we have examined of the type specimens all agree with the concept of P. bilimeki used here and in Longino and Cox (2009).

Should P. floridana therefore be synonymized under P. bilimeki? Wilson (2003) offered that the former might represent the northernmost population of the latter, and recent phylogenetic analyses (Economo et al. 2015; Moreau 2008) show these two as sibling taxa. Based on the results of her analysis, Moreau (2008) found that her samples of P. bilimeki (Costa Rica, RA0162) and putative P. floridana (Florida, RA0331) were each other’s closest relatives, and that this pair was sister to P. anastasii (Costa Rica). The result is also supported by Economo et al. (2015), which found a shallow divergence separating P. bilimeki from putative P. floridana, especially compared to the deep divergence separating these sister taxa from P. anastasii. Moreau (2008) concluded that in order for P. anastasii to be a valid member of P. bilimeki, as proposed by Wilson (2003), P. floridana would also have to be accepted as a synonym of P. bilimeki.

We suggest that this conundrum stems from the common misapplication of the name P. floridana (a shiny gaster species) to collections of what are in fact the North American population of P. bilimeki (a matte gaster species). Naves (1985) came to a similar conclusion in his revision of the Pheidole of Florida, “P. floridana seems to be confined to southeast Florida in the Miami area. This is the only place where I was able to locate this species. Due to its close relationship to P. anastasii the latter has been misidentified as P. floridana many times, thus, mistakenly extending the supposed range of P. floridana. P. anastasii is actually the species widely distributed in Florida, while floridana is absent or at least must be rare in most of the state.”

One explanation for the confusing phylogenetic results is that RA0331 actually refers to P. bilimeki Mayr, and that true members of P. floridana Emery from the Miami area were not included in the aforementioned phylogenetic analyses. The samples of RA0331 were collected in central Florida from Polk County, well outside the Miami area from which the P. floridana Emery is known (Naves 1985). Deyrup, who collected and identified the specimens of RA0331, has previously (2003; 1988; 1989) applied the name P. floridana to matte gaster specimens that earlier authors (Naves 1985; Smith 1933; Wheeler 1932) would have considered P. anastasii Emery, and that we consider P. bilimeki Mayr.

To properly ascertain the taxonomic status of P. floridana Mayr we suggest a future phylogenetic analysis that includes specimens matching the type material of P. floridana, preferably from the Miami area. If there is evidence supporting the conspecificity of samples matching our concept of P. bilimeki, then the validity of P. floridana Emery must be revaluated. If, rather, the P. floridana samples are heterospecific with respect to P. bilimeki, then there are at least two hypotheses that could explain this result. One is that P. floridana is endemic to Florida. The second, perhaps more compelling albeit ironic explanation, would propose the Miami population of P. floridana is conspecific with a Neotropical species inadvertently introduced to Florida. Miami is a major shipping port and was the gateway for many introduced ants over the past two centuries (Deyrup et al. 2000).

The taxonomic confusion surrounding whether published accounts refer to our proposed concept of P. bilimeki, or instead to either P. floridana or P. anastasii, makes it difficult to ascertain the natural history of the species. The following account given by Longino and Cox (2009), however, refers definitively to P. bilimeki. They report that P. bilimeki is a common species in open, recently or frequently disturbed habitats. In Costa Rica it occurs in lowland dry forest, lowland wet forest, and montane habitats to about 1500 m elevation. It is a common ant of roadsides, nesting under stones or in dead fence posts. It is a frequent pest ant in houses and is a common ant at baits in second growth dry forest vegetation in seasonally dry Guanacaste Province. It can also be abundant and dominant in large disturbances deep within primary forest reserves. We tentatively treat the account given by Wilson (2003) for P. floridana as referring to the North American population of P. bilimeki. That account stated that winged reproductives have been found in nests during September and October, and that the species occurs in a variety of woodland habitats, nests in soil, litter, and rotten wood, and in both xeric and mesic situations. It also noted the observation of Stefan Cover that colonies are monogynous, may contain 1000 or more ants, and are sometimes polydomous. Cover observed that the species is omnivorous, but does not appear to harvest seeds (but see Naves 1985). Naves (1985) discussed the biology of P. bilimeki (as P. anastasii) in Florida. He found the species most often nesting under the bark at the base of pines or along the roots, but occasionally found it nesting in the soil. The colonies he observed supported over 600 workers with a 5:1 ratio of minors to majors. Mature colonies were monogynous, although in laboratory conditions colonies that lost their original queen would accept other conspecific queens. Several colonies were discovered with two or three founding females, but laboratory experiments found that one would kill the others before the rearing of the first brood. Naves also recorded that the species feeds on seeds, fruits, and scavenges on small dead arthropods and is predaceous on small live arthropods.

Pheidole bilimeki is a Neotropical native that ranges from northern South America to southern North America and across the Caribbean. The records included here from the southern United States have previously been treated as P. anastasii and P. floridana (see discussion). Pheidole bilimeki was not reported from Florida until 1932 (Wheeler). While it is possible that the penetration of P. bilimeki into the southern United States represents a recent dispersal event, even one that has been anthropogenically facilitated, there are several reasons for considering P. bilimeki as native to the region. Firstly, the range of North American populations appear contiguous with those of Mexico and the Caribbean, and gene flow among them is probable. Secondly, populations from Florida are known to host two parasites, a mermithid that parasitizes workers, and a hymenopteran parasite species of the genus Orasema (Naves 1985). Pheidole bilimeki has been recorded from greenhouses in Illinois and Ohio in North America. The species has also been found indoors and greenhouses across Europe, including the Netherlands (Boer and Vierbergen 2008), Germany (Forel 1908), Great Britain (Forel 1908), Ireland (Stelfox 1927), and Switzerland (Forel 1908). The only occurrence of P. bilimeki in Jamaica is reported by Wilson (2003). Although the species might occur there, it is also possible that Wilson was referring to P. jamaicensis Wheeler. The single Mauritius occurrence is of a single minor worker examined by Donisthorpe (1946), but this specimen more likely refers to the superficially similar P. parva which is widespread across the island and its neighbors in the Indian Ocean.

Pheidole bilimeki is a synanthropic species with a high tolerance for habitat disturbance. It is occasionally found indoors, especially in greenhouses. There is little indication that is causes significant impact to agricultural systems or native ecosystems.

Color yellowish brown to dark brown. MajorHW 1.13–1.44, HL 1.13–1.56, SL 0.80–0.95, CI 92–100, SI 61–71 (n=15, Eguchi 2001a; 2008; Fischer and Fisher 2013). Head square to subquadrate (Fig. 7); rugoreticulate on posterolateral lobes and laterad of frontal carinae (Fig. 13a), but frons dominated by long, well-organized and parallel longitudinal rugae (Fig. 13b). Antennal scrobes indistinct to moderately impressed, but frontal carinae always forming a border capable of accepting the antennal scape (Fig. 13c). Frontal carinae relatively longer, extend 4/5 distance of head before terminating (Fig. 14). Promesonotum in profile with two convexities (Fig. 5), the large anterior dome in addition to a distinct mound or prominence on the posterior slope. Postpetiole not swollen relative to petiole (Fig. 3). MinorHW 0.52–0.63, HL 0.66–0.73, SL 0.77–0.87, CI 79–88, SI 133–154 (n=16, Eguchi 2001a; 2008; Fischer and Fisher 2013). Head predominantly glossy (Fig. 36), lacking punctation or rugulae above eye level. Posterior head margin weakly convex to flat in full-face view (Fig. 45). Antennal scapes long (e.g. Fig. 39), but not surpassing the posterior head margin by more than 2× eye length. Promesonotum in profile with two convexities, the large anterior dome (Fig. 43a) in addition to a distinct prominence on the posterior slope (Fig. 43b). Promesonotal prominence relatively flat (Fig. 49a). Metanotal depression relatively deep (Fig. 49b). Petiole and postpetiole glossy to very weakly sculptured laterally (Fig. 48). Postpetiole not swollen relative to petiole (Fig. 3).

Pheidole fervens is a medium to large sized species with long limbs. It belongs to the P. fervens clade along with its Australasian congeners P. cariniceps, P. hospes, P. impressiceps, and P. oceanica (Economo et al. 2015). The major workers have strong cephalic rugulae that become reticulated towards the posterior of the head and the minor workers have completely glossy heads with very long antennal scapes. Majors and minors of the species can be separated from those of P. megacephala and P. noda by the postpetiole which is not swollen compared to the petiole (Fig. 3), and the promesonotum which has the large anterior dome in addition to a distinct prominence on the posterior slope (Fig. 5, major; Fig. 43, minor). The minors of P. fervens can also be separated from those of P. megacephala by their larger size and longer antennal scapes (Fig. 39). The majors are easily distinguished from P. megacephala by the very sculptured head (Fig. 13).

Among species treated here, P. fervens is most easily confused with its close relative, P. indica, and the characters used to separate these two are subtle. For both subcastes, the promesonotal prominence is flatter in P. fervens (Fig. 49a, minor; Fig. 63a, major) compared to that of P. indica (Fig. 50a, minor; Fig. 64a, major). The eyes of P. fervens minors (Fig. 65) are relatively smaller than those of P. indica minors (Fig. 66), especially in comparison to antennal segment 10. The propodeal spines of P. fervens are weaker, narrower, and more downcurved in majors of P. fervens (Fig. 63b) compared to those of P. indica (Fig. 64b). Readers are referred to Eguchi (2004b; 2008) for characters used to separate P. fervens and P. indica from their Asian congeners.

In the Pacific Island region P. fervens is often confused with the nearly identical P. oceanica, which is native to that region. The carinae between eye and mandible are branching and reticulated in the majors of P. fervens (Fig. 67), versus parallel and not reticulated in those of P. oceanica (Fig. 68). This character was erroneously reversed in the key provided in Sarnat and Economo (2012). The minors are more difficult to separate, but in P. fervens the length of propodeal spine is equal to or less than the diameter of propodeal spiracle (Fig. 69), whereas in P. oceanica it is greater (Fig. 70).

For such a ubiquitous species across its native and introduced range, very little is known about the biology of Pheidole fervens. It is a synanthropic species with a high tolerance for disturbance (Eguchi 2004b; Fischer and Fisher 2013; Martínez 1996), but can also thrive under some degree of canopy cover (Morrison 1996; Sarnat and Economo 2012). In Fiji, where it is likely a recent colonizer, it was collected most frequently in human dominated landscapes between 0–800 m, although several collections were also made from primary forest at low elevations. In Hawaii, where it is definitely an introduced species, it is more abundant locally in wet regions than P. megacephala (Gruner et al. 2003) and occurs in the hot lowlands only below 900 m (Reimer 1994). In the Philippines, P. fervens is found in irrigated lowlands (rice fields) where it is characterized as dominant species capable of displacing S. geminata in the dry season (Way et al. 1998). In Japan it occurs in open land grading to forest edge (Harada et al. 2009; Ogata 1981). Pheidole fervens recruits in large numbers to bait and forages both on the ground and on vegetation (Sarnat and Economo 2012). Baiting experiments on Pacific Islands found that P. fervens can act as a numerically and behaviorally dominant species capable of excluding other invasive ant species (including Anoplolepis gracilipes, Nylanderia bourbonica, and Tetramorium bicarinatum) from baits (Morrison 1996). Although foragers can be slow to discover food resources, once found they can recruit in large numbers and displace competing species (Morrison 1996). Experiments in China suggest that P. fervens can provide some degree of biotic resistance to the Red Imported Fire Ant (Solenopsis invicta) by acting in groups to dismember the limbs of individual fire ants (Chen et al. 2011). Martínez (1996) suggested the California population of P. fervens was polydomous, and Passera (1994) suggested the Hawaii population is unicolonial and polygynous, but detailed colony-level studies of the species are required to verify these claims. Wittenborn and Jeschke (2011) attributed their assertion that P. fervens practices dependent colony founding to Harris et al. (2005a), but we were unable to find any reference to colony foundation in that report and cannot substantiate their evidence.

We consider Pheidole fervens as native to a broad expanse of the Indo-Malay region spanning from India east to the Philippines and south to the islands west of New Guinea. This is a broad and admittedly arbitrary boundary, but a more precise circumscription of the native range requires a population-level analysis outside the scope of the present study. In particular, it is difficult to ascertain the extent of its range into the Pacific Island region prior to the Anthropocene. The only known occurrence of P. fervens from New Guinea was a single record from the westernmost part of the island (Emery 1887b). East of New Guinea, however, the species is established on nearly all islands of the Pacific, including those which were uninhabited by any ant prior to human arrival. Although it is quite possible that P. fervens reached some of these islands without human assistance – especially those between Taiwan and mainland Japan – we treat these as introduced populations. And although established on Mauritius, the species is rarely encountered there and is currently known from only two localities (Fischer and Fisher 2013). The only record of introduction in North America is a California population that established nests in cracks of roads and along the sides of buildings in a two-block area of downtown Los Angeles (Martínez 1996). Pheidole fervens has been collected from greenhouses in the Netherlands (Boer and Vierbergen 2008), and is frequently intercepted by quarantine inspections (Ward et al. 2006).

Pheidole fervens can be a dominant species where it is locally abundant. Although few studies have measured the effect of P. fervens on native ecosystems, we predict that it could negatively impact native arthropods. We were unable to find documentation on the effect of P. fervens on agricultural systems, but it can be among the most abundant ant species in irrigated lowland crop systems such as rice fields. Pheidole fervens can also be an indoor nuisance species (Wilson and Taylor 1967), but is not a risk for structural damage. According to New Zealand records, the species is among the most commonly intercepted ants in that country (Ward et al. 2006). Sixty-nine percent of the interceptions were in freight from Fiji (> 92% from the Pacific Islands). Interceptions were mostly in fresh produce (69%) and cut flowers (8%). Pheidole fervens was also intercepted multiple times in air passengers’ luggage and shipping containers. The species could become more globally widespread in the future.

See notes under P. flavens-complex. Neotype major: HW 0.72, HL 0.74, SL 0.42, CI 103, SI 58. Paraneotype minor: HW 0.34, HL 0.42, SL 0.34, CI 124. SI 100. Non-type measurements, major: HW 0.68–0.83, HL 0.74–0.88, SL 0.39–0.42, CI 87–97, SI 52–59. Non-type measurements, minor: HW 0.34–0.45, HL 0.39–0.49, SL 0.34–0.42, CI 81–93, SI 89–104.

Pheidole flavens belongs to the P. flavens-complex along with a putatively large number of other nominal taxa. However, the P. flavens group as conceived by Wilson (2003) is now known to be polyphyletic (Economo et al. 2015; Moreau 2008). Readers are referred to the P. flavens-complex for additional discussion of identification, taxonomy and systematics. The taxonomy of P. flavens and its close relatives remains in a state of confusion. It is beyond the scope of the present study to resolve this issue, but we contribute the following discussion as a step towards that goal.

Pheidole flavens was originally described by Roger from Cuba, but the type material is considered to be lost. Wilson (2003) designated a neotype from Cuba and synonymized a total of eight nominal taxa with P. flavens. Of these, P. greggi Naves (Florida) and perhaps P. flavens st. spei Santschi (Mexico) are most similar to the Cuban neotype. They, together with the types of P. moerens subsp. creola, are the only specimens examined thus far that have clearly reticulated rugulae posterior to the scrobes of major workers. Naves’ (1985: fig. 55) concept of P. flavens Roger, at least as evidenced by his figures and descriptions, more closely matches our concept P. navigans, a species that is spreading across the southeastern United States. The syntype major of Pheidole flavens var. vincentensis Forel differs substantially from the neotype in that the head is completely glossy between the rugulae, which are themselves entirely longitudinal and do not extend far beyond the maximum extent of the antennal scapes in repose. These characters make it at least superficially more similar to P. moerens and P. navigans. Pheidole flavens r. gracilior and P. navigans were both described by Forel from workers intercepted at a Hamburg quarantine facility, which is testament to the dispersive ability of this complex. The syntype major of the latter species and that of P. floridana subsp. aechmeae Wheeler, also described from Mexico, are quite similar. Pheidole exigua var. tuberculata Mayr has the strongly convex head and promesonotal dome of P. exigua Mayr, and also exhibits tuberculate angles on the mesonotal declivity. Type specimens of P. flavens var. haytiana Forel were not examined for this study.

The only material from outside Central America and the Caribbean that we were able to confirm as matching the Wilson’s neotype was from Florida. The Florida populations referred to here as P. flavens and P. navigans are almost certainly heterospecific. We suspect that Nearctic records of P. flavens outside of Florida such as those reported from Louisiana (Colby and Prowell 2006; Dash and Hooper-Bùi 2008) refer to either P. bilimeki or the species we are treating as P. navigans in the southeastern USA.

The biology of Pheidole flavens, as currently conceived, was reviewed by Wilson (2003) with contributing observations by Jack Longino. The species prefers rotting wood, but also nest beneath the bark of trees, in dead knots on tree trunks, in sod on rocks, in the soil beneath stones, and in epiphyte masses. In the Caribbean it is recorded from forests and thickets from sea level to 900 m, and in Costa Rica it occurs in both wet and dry forests below 1000 m. The nest galleries are diffuse and irregular. Mature colonies are large containing up to thousands of workers. Workers collect small arthropods and will recruit to sugar baits.

Pheidole flavens is among the most widespread and abundant species of its genus in the New World, although this range might be representative of multiple cryptic species. As currently conceived, however, we consider P. flavens native from southern Mexico east through the Caribbean and south to Uruguay and northern Argentina. It is difficult to know whether the disjunction separating the western and eastern regions of South America is accurate or a sampling artifact. The Florida population is believed to have derived from an accidental introduction by commerce (Deyrup et al. 2000; Wilson 2003).

Pheidole flavens (or at least it’s very close relatives) are easily transported long distances, and are known to hitchhike with fresh plant material (Wilson 2003). However, the species is not known to cause significant impact to agricultural systems or native ecosystems, and is not considered a house pest (Hedges 1998; Klotz et al. 1995).

Light to dark reddish brown. MajorHW 1.32–1.74, HL 1.31–1.76, SL 0.73–0.91, CI 94–117, SI 47–62 (n=22). Head subquadrate (Fig. 7); rugoreticulate on posterolateral lobes and laterad of frontal carinae (Fig. 13a), but frons dominated by long, well-organized and parallel longitudinal rugae (Fig. 13b). Frontal carinae extend 3/4 distance of head before terminating (Fig. 15). Antennal scrobes indistinct to moderately impressed, but frontal carinae always forming a border capable of accepting the antennal scape (Fig. 13c). Hypostoma with weakly produced median tooth and submedian teeth. Promesonotum in profile with two convexities (Fig. 5), the large anterior dome in addition to a distinct mound or prominence on the posterior slope. Postpetiole not swollen relative to petiole (Fig. 3). MinorHW 0.50–0.65, HL 0.60–0.74, SL 0.64–0.81, CI 72–90, SI 120–149 (n=20). Head predominantly glossy (Fig. 36), lacking punctation and or rugae above eye level. Posterior head margin weakly convex to flat in full-face view (Fig. 45). Antennal scapes long (e.g. Fig. 39), but not surpassing the posterior head margin by more than 2× eye length. Promesonotum in profile with two convexities, the large anterior dome (Fig. 43a) in addition to a distinct prominence on the posterior slope (Fig. 43b). Promesonotal prominence relatively convex (Fig. 50a). Metanotal depression relatively shallow (Fig. 50b). Petiole and postpetiole glossy to very weakly sculptured laterally (Fig. 48). Postpetiole not swollen relative to petiole (Fig. 3).

Figure 73. 

Relative morphometric measurements of P. indica paralectotypes, specimens previously determined as P. indica, and specimens previously determined as P. teneriffana. All values are in mm. A Head length vs. head width, major workers. B Head length vs. head width, minor workers. C Scape length vs. head width, major workers D Scape length vs. head width, minor workers.

Pheidole indica is a medium to large reddish brown species with relatively long limbs. It belongs to the P. fervens clade along with its Australasian congeners P. cariniceps, P. fervens, P. hospes, P. impressiceps, and P. oceanica (Economo et al. 2015, unpublished data). The major and minor workers are distinguished from those of P. megacephala by the lack of a swollen postpetiole (Fig. 3). The majors are also easily separated from those of P. megacephala by the strongly sculptured head (Fig. 13). The minors can be confused with those of P. megacephala because both have glossy heads. However, the minors of P. fervens can be separated from those of P. megacephala by the relatively longer antennal scapes (Fig. 39 vs. Fig. 40) and the presence of a promesonotal prominence (Fig. 43 vs. Fig. 42). Pheidole indica is broadly sympatric with P. noda and P. fervens. It is easily separated from the former by the lack of a swollen postpetiole (Fig. 3 vs. Fig. 2). Separation from P. fervens is quite difficult, and readers are referred to corresponding section under that species for distinguishing characters. Readers are referred to Eguchi (2004b; 2008) for characters used to separate P. indica and P. fervens from their Asian congeners.

Pheidole indica was originally described from India. Eguchi (2004b) synonymized several other Asian congeners under P. indica and discussed taxonomic differences used to distinguish it from P. fervens and other morphologically similar species. We synonymize P. teneriffana under P. indica based on morphological analysis of the type specimens and genetic analysis of previously determined specimens (unpublished data). Forel, in his original description of P. teneriffana, noted the similarity between it and P. striativentris [= indica].

The biogeographical origin of P. teneriffana has been a minor mystery of the past century, as revealed by the recent review of the species by Wetterer (2011). There appeared to be general consensus that P. teneriffana was native to at least some portion of North Africa, Arabia, the Middle East or the Mediterranean. Santschi (1918), suggested the upper Nile area (South Sudan). Wilson (2003) suggested North Africa and potentially the Canary Islands. Collingwood et al. (2004) suggested it was native throughout northern Africa and observed it to be, “spreading over a wide front in the Middle East, Arabia and the Mediterranean countries.” Wetterer (2011) found the distribution of P. teneriffana enigmatic, “Curiously, most Old World records of P. teneriffana are subtropical, but all New World records are tropical, except one from California…If P. teneriffana is truly native across North Africa, it is remarkable how few records I found from any North African country other than Egypt.”

In Asia P. indica is known to nest in soil or under stones in open and dry habitats (Eguchi 2004b). It is among the most widespread Pheidole species in Asia. In the Caribbean Wetterer (2011) found P. indica [as P. teneriffana] almost exclusively on beaches and at highly disturbed urban sites, particularly in waterfront areas. In northern Africa, Santschi (1908) noted the tramp-like distribution of what he treated as P. teneriffana, “This species, described by Forel on samples from the Canary Islands, was sent to me from Cairo. I discovered it most recently in Sousse [Tunisia], in the park, near the port. As it does not exist in the interior, I think it is one species cosmopolitan tendencies. It nests in the ground and under stones.” Santschi (1934) later reported the species from Alexandria, Egypt, and noted that P. teneriffana was rarely reported far from seaports. Collingwood et al. (1997) reported that in the United Arab Emirates, P. indica [as P. teneriffana] was populous in irrigated gardens and along the coast where it appeared to be spreading rapidly, possibly to the detriment of local species. The species has also been reported from urban areas of the Balearic Islands where it is common in the gardens and trees and on sidewalks near the harbor (Gómez and Espadaler 2006). Fischer and Fisher (2013) reported P. indica [as P. teneriffana] from the Malagasy region. It was collected on the Comoros, Mauritius, the Seychelles, and from coastal towns in Madagascar, usually from under stones, ground nests, or foraging on the ground or lower vegetation in urban or garden habitats at elevations below 300 m. It was also found on Mayotte in native littoral and secondary forest below 10 m.

Perhaps the most detailed study of P. indica in the New World comes from the account of Martínez (1992) who reported a vigorous population, represented by a putatively single polydomous colony spanning several hectares, that was discovered in Long Beach, California in 1989. Martínez (1992) reportedly observed 23 inseminated queens from a single colony that was changing nest sites (although no details are given for how he knew the queens were inseminated). He described the colony nests as low mounds on the soil, along curbs or sidewalks, at the edges of lawns, in cracks in pavement, and at the bases of trees. New colonies were started by budding. Workers foraged night and day unless temperature exceeded 26 °C, taking seeds and scavenging dead or dying insects. They were observed feeding on sweet or greasy foods, but were not seen tending aphids. Martínez (1992) observed the species attacking native ants, including Pogonomyrmex californicus (Buckley). More remarkably, he reportedly observed P. indica destroying colonies and taking over nest sites of Linepithema humile. Despite the purported success of these battles, P. indica must have lost the larger war against L. humile, as the eventual extirpation of the Californian population was attributed to the Argentine ant (Gulmahamad 1999).

We treat all occurrence records from the regions of Indomalaya west of the Korean Peninsula as native. The Korean and Japanese populations are considered introduced (Choi and Bang 1993; Choi et al. 1993a; Choi et al. 1993b; Terayama 1992), and additional portions of the range in Asia might also have resulted from anthropogenic transport. Pheidole indica has been introduced to scattered localities across the globe, although the vast majority of these records were attributed to its junior synonym, P. teneriffana. Introduced populations have been reported from the Mediterranean, northern Africa, the Malagasy region, Western Australia, Peru, the Caribbean, and southern California.

Pheidole indica is not considered to be a major pest to either agriculture or native ecosystems. Although the species is tolerant of disturbed and urban areas, we found no reports of it infesting structures. Few studies have measured the effect of P. indica on ecosystem health, but we predict that it could negatively impact native arthropods. The species is continuing to spread across the globe and further studies are required to test its ecological and agricultural impact outside its native range.

Light brown to dark brown. MajorHW 1.10–1.54, HL 1.04–1.59, SL 0.59–0.76, CI 97–106, SI 47–58 (n=19, Fischer and Fisher 2013). Head heart-shaped (Fig. 6); posterior 1/3 of dorsal surface smooth, glossy and entirely lacking rugoreticulate sculpture. Hypostoma lacking distinct median and submedian teeth. Promesonotum in profile forming a single dome (Fig. 4), lacking a distinct mound or prominence on the posterior slope. Postpetiole with a posterodorsal (Fig. 1a) and anteroventral (Fig. 1b) bulge. MinorHW 0.50–0.61, HL 0.57–0.68, SL 0.61–0.72, CI 86–92, SI 114–122 (n=20, Fischer and Fisher 2013). Head predominantly glossy (Fig. 36), lacking punctation and or rugae above eye level. Antennal scapes surpass posterior head margin by approximately same length as eye (Fig. 40). Promesonotum in profile forming a single dome (Fig. 42), lacking a distinct mound or prominence on the posterior slope. Postpetiole with a posterodorsal (Fig. 1a) and anteroventral (Fig. 1b) bulge.

Pheidole megacephala is a medium sized species of variable color that is most easily recognized outside of its native range by the heart-shaped head and bulging postpetiole. It belongs to a diverse and taxonomically confusing clade of morphologically similar taxa centered in the Afrotropical and Malagasy regions. Both major and minor workers are distinguished from all other introduced Pheidole by the swollen shape of the postpetiole (Fig. 1). Pheidole noda also has a swollen postpetiole, but whereas the postpetiole of P. megacephala is characterized by a posterodorsal and anteroventral bulge, that of P. noda is formed as a high dorsally bulging dome that is tallest at its midpoint.

Pheidole megacephala has often been confused for P. pallidula Nylander in Europe, especially in the Mediterranean region. The introduced populations of P. megacephala can be distinguished from P. pallidula by the following characters. For both major and minor workers the postpetiole of P. megacephala has a posterodorsal (Fig. 1a) and anteroventral (Fig. 1b) bulge, while that of Pallidula is not swollen relative to petiole (Fig. 3). The propodeal spines of both subcastes are distinct in P. megacephala but are strongly reduced in P. pallidula. Additionally, the major worker of P. megacephala has a heart shaped head that broadens significantly posterior to eye-level (Fig. 6) while the head of Pallidula is more rectangular (more approximate to Fig. 7).

Accurate identification within the Afrotropics is more problematic. While for Madagascar previously described subspecies have been synonymized with P. megacephala (Fischer and Fisher 2013), the taxonomy of the megacephala group in Africa remains rather chaotic with a number of unrevised subspecies, most of which remain insufficiently characterized. In a taxonomic overview of the group, Emery (1915) studied type and non-type material of P. megacephala-related species, yet for several subspecies he was not able to define clear species limits from the multitude of different, yet highly similar, phenotypes. We suspect that some of those names are probably due to intraspecific variation within P. megacephala and P. punctulata Mayr. Other, morphologically unique taxa like P. megacephala nkomoana Forel are clearly valid biological species. However, without a comprehensive taxonomic treatment supported by a robust phylogeny, the following species characterizations may be subject to future taxonomic changes.

Within the megacephala group, minor workers are difficult to separate morphologically and thus have only limited use for species identification, but the majors tend to be more distinct in their morphologies and can be separated by differences in head and body shape and sculpture, and in size and pilosity, although the limits are often unclear and characters are sometimes distributed along a continuum rather than being separated into distinct, clear-cut states.

Major workers of P. megacephala melancholica Santschi are characterized by presence of weak punctures on the majority of the head, including the sides in lateral view, promesonotum with punctures and irregular transverse rugulae, and moderately abundant short and stout standing hairs on head and body, whereas major workers of P. megacephala entirely lack punctures on the posterior 1/3 of the head, have a mostly smooth and glossy promesonotum, and often possess longer, more flexuous standing hairs, which often branch at the tips. Pheidole megacephala nkomoana majors are characterized by a weakly defined antennal scrobe and relatively long frontal carinae that reach about ¾ towards the posterior head margin, two well-defined submedian hypostomal teeth, a weak prominence on the promesonotal dome, and very long, flexuous standing hairs on the dorsal promesonotum. Also the spines tend to be shorter than in P. megacephala, in length almost equal to the diameter of the propodeal spiracle. Both subspecies have been described from and collected in western African forests. Another closely related species to P. megacephala is P. punctulata. It is very widespread in sub-Saharan Africa and usually found in dry forests and grassland habitats. Morphologically close to P. megacephala, its major workers can be distinguished by their often enlarged and strongly heart-shaped heads, the presence of a softly or superficially punctuated sculpture on parts of the head dorsum, promesonotum, postpetiole and gaster, and relatively uniform, short and stout, erect hairs covering the body. Minor workers tend to be slightly larger and more robust than in megacephala, often with a few oblique carinae present between the eyes and the mandibles and reaching the posterior eye level, the hairs similar as in major workers and usually more abundant than in P. megacephala.

Morphologically very similar to P. punctulata are P. megacephala ilgi Forel, megacephala impressifrons Wasmann, and megacephala rotundata Forel. Like P. punctulata, they are usually found in drier forest and grassland habitats and their workers seem to be highly polymorphic, which means that in addition to normal major workers, colonies are capable of producing so-called supermajors. These supermajors possess a very strongly heart-shaped head, which can be disproportionately big compared to the size of the mandibles and the rest of their bodies. As Emery (1915) stated for P. megacephala rotundata, on first glace they look quite distinct from P. punctulata, but at closer examination of series with different major worker sizes it seems impossible to define species limits. From our own observations it seems likely that these subspecies are a result of sampling bias and phenotypic variation within P. punctulata, rather than historic speciation events (Fischer et al., in preparation). Incomplete sampling can also be a problem when only smaller major and minor workers are collected, which are often very similar to those of P. megacephala, with very similar head sculpture and general morphology.

In the Malagasy region, P. megacephala can be confused with three other species: Pheidole punctulata spinosa Forel, which, on average, has longer spines, a slightly higher propodeum and a more extensively smooth and glossy posterior portion of the head in the larger major workers. Pheidole megatron, which was described from the Comoros and is possibly present in the Northwest of Madagascar as well, is characterized by major workers with a less heart-shaped, and slightly more rectangular head shape, and sometimes sculpture and rugulae present on the posterior head portion (see Fischer and Fisher 2013). Finally, P. decepticon, described from Mayotte and distributed over several of the smaller Southwest Indian ocean islands, is characterized by possessing a denser, more prominent and longer pilosity as well as slightly smaller, less rounded ventral bulges on the postpetiole in both minor and major workers (see Fischer and Fisher 2013). It is however possible that P. decepticon is a geographic variation of and conspecific with P. punctulata spinosa.

Pheidole megacephala is listed among the top five invasive ants (Lowe et al. 2000). Although this species prefers humid and disturbed habitats where it is usually found in very high abundances (Burwell et al. 2012; Hoffmann et al. 1999; Wilson 2003), it can generally be found in a large variety of landscapes, from coastal habitats to human settlements and plantations in lower elevations, degraded dry forest, to mid-elevation rainforest or even montane forest – in Papua New Guinea up to 2150 meters altitude (Fischer and Fisher 2013). The distribution range and activity of P. megacephala appears to be somewhat limited by susceptibility to desiccation and higher temperatures. Thus, colonies are often found in more humid microhabitats, and workers tend to forage inside the leaf-litter and at night, or even build covered trails (Greenslade 1972, personal observations). However, some studies reported that on smaller islands or after successful introduction in a new area, P. megacephala expanded its range and invaded into the forest interiors where it attacked and displaced other introduced and natively occurring ant species (Burwell et al. 2012; Hoffmann 1998). In a citrus orchard in Tanzania for example, P. megacephala was able to partly displace highly territorial and competitive Oecophylla weaver ants (Seguni et al. 2011). Pheidole megacephala is an especially common and abundant nuisance and pest on islands, which are generally more strongly impacted by invasions of alien species.

Part of the success of P. megacephala as a pantropic pest species is its generalist behavior. Like many other Pheidole species its diet is broadly omnivorous with a large proportion of its food probably acquired by scavenging on the ground. Pheidole megacephala is also a good predator with an efficient nest mate recruitment that enables the species to dominate baits and to retrieve prey too large for single workers to carry (Dejean et al. 2008; Dejean et al. 2007). Devastating effects on the abundance and diversity of native invertebrates, in northern Australia for example, are well documented (Hoffmann 1998; Hoffmann et al. 1999; Hoffmann and Parr 2008). Pheidole megacephala has also been documented to negatively impact agricultural systems. Workers tend plant and crop-damaging scale insects for honeydew (Campbell 1994; Gaigher et al. 2011; González Hernández et al. 1999; Greenslade 1972; Petty and Tustin 1993; Reimer et al. 1993), protect plants with extrafloral nectaries from phytophagous insects and possibly collect seeds (Hoffmann 1998). A recent study experimentally evaluating the performance in interference competition found that P. megacephala ranked lowest among seven of the world’s worst most destructive invasive ant species (Bertelsmeier et al. 2015). The authors, citing Dejean et al. (2008) suggested that P. megacephala does not dominate invaded ant communities through direct physical interactions (interference competition) but by raiding their colonies.

Nesting sites are variable and can occur in any crack and crevice that is large enough for them to enter, including soil, inside rotting logs, under rocks, in houses or in tree bark. As in several other invasive ant species, colonies are polygynous, and dependently founded via budding, with nests in large areas often forming supercolonies (Hoffmann 1998) that aggressively fight other ants or outcompete them by depleting their prey and other resources (Dejean et al. 2008; Fournier et al. 2009; Hoffmann et al. 1999; Vanderwoude et al. 2000).

Pheidole megacephala is a cosmopolitan species that has established across the globe as a household and agricultural pest throughout the tropics. Wetterer (2012) provided a detailed review of the worldwide spread of P. megacephala, and cites Wheeler’s statement (Wheeler 1922a) that it is most likely of Afrotropical or Malagasy origin, the only two regions with a diversity of related species (“subspecies and varieties”). Theoretically it is possible that a common ancestor of P. megacephala and the Malagasy endemics P. punctulata spinosa, P. megatron and P. decepticon arrived on the islands in prehistoric times, diversified there, and that P. megacephala was later transported to all other regions including Africa only after the arrival of humans. But the distribution of P. megacephala on Madagascar strongly resembles the distributions of other invasive species on the island – e.g. those of Monomorium floricola, M. pharaonis, Tapinoma melanocephalum, Technomyrmex albipes, Trichomyrmex destructor. While P. punctulata spinosa has established a broad distribution range across the island’s variable habitats and elevations, P. megacephala, like the other invasives, is found mostly along the coast, in low elevation and disturbed habitats or near human settlements.

Similar to Wheeler’s observation, our argument for the “out-of-Africa” hypothesis is an overall much higher complexity in different morphotypes and species-level diversity in African megacephala group taxa and the presence of both, very closely, but also more distantly related taxa (e.g Pheidole aurivillii Mayr). For these reasons and for the purposes of this study, we consider all records from Africa to represent the native range of Pheidole megacephala. However, a further resolution will require a comprehensive phylogeographic study of the species and its allied taxa, especially from the poorly studied and sampled African region.

Populations of P. megacephala recorded from the southwestern extent of the Arabian Peninsula are treated as native as this region is commonly considered as belonging to the Afrotropics. However, recent studies on generic distributions of global ant diversity that find little support for including any portion of the Arabian Peninsula in the Afrotropics (unpublished data). Until robust phylogeographic data is available for P. megacephala, this decision must be considered tentative and open to future revision.

We do agree with Wetterer’s (2012) conclusions that records of P. megacephala from Mediterranean Europe northward are either temporary indoor records or misidentifications of P. pallidula. Outside of Africa, the Malagasy region and the range of P. pallidula (western Palearctic), P. megacephala is easily recognized as it does not co-occur with species of similar morphology. We therefore consider all records reviewed from outside the aforementioned regions as confirmed unless otherwise stated.

The following records are considered dubious mostly because there is reason to believe they represent misidentifications of P. pallidula. However, it is possible that some of the following literature records were based on accurate identifications, but that P. megacephala was since extirpated from the referenced localities. This latter possibility is plausible especially for the Mediterranean region where L. humile has established a stronghold. For example, (Heer 1852) described Oecophthora pusilla (=P. megacephala) as ubiquitous on the island of Madeira, “In the town of Funchal there is probably not a single house that does not harbor millions of the tiny creatures…” Less than a century later Wheeler (Wheeler 1927b) reported, “Now it is an interesting fact that the Argentine ant, soon after its arrival in Madeira, completely replaced the Pheidole as a house ant.” Similar instances of well-established populations of introduced ant species becoming locally extirpated have been documented (Moreau et al. 2014; Wetterer 2006).

Algeria: The material referred to by André (1883) P. megacephala is distinguished by that author from P. pallidula only by the difference in size of the propodeal spine, and was otherwise observed to be identical. Considering the other characters separating these two species discussed earlier, we tentatively consider this record to be a misidentification of P. pallidula. Croatia: The material listed from this country (Petrov and Collingwood 1992; Petrov and Legakis 1996) is considered to refer to P. pallidula according to Bračko (2006). Egypt: Egypt is the type locality of the nomen oblitumFormica edax Forskål. Emery (1892) wrote that edax is undoubtedly a small Pheidole, and possibly refers to P. megacephala. Dalla Torre (1892) was also uncertain as to which species (or even genus) the name edax referred to. Given the uncertainty of these two authors, the occurrence of P. pallidula in Egypt and the unconfirmed single literature record of Bakr et al. (2007), it is difficult to know when P. megacephala was first reported from Egypt. France: Bignell (1901) reported the ant species listed in his study of Corsica were identified by Saunders, who is known to have confused P. pallidula for P. megacephala. As P. pallidula was not listed in the publication, we consider the record to either be a misidentification of that species or from an extirpated population. Greece: The only primary references to an outdoor occurrence we could confirm are Collingwood (1993) and Borowiec and Salata (2012). The former authors reported P. megacephala was found only once during their study of five Greek islands on the threshold of a small hotel in Pigadhia on Karpathos. The second study reported finding the species on a road in Crete. The record from Macedonia in (Karaman 2011) is from material identified by Petrov. We tentatively follow (Bračko 2006) as treating this as a misidentification of P. pallidula. Italy: Piedmont is the type locality for Myrmica trinodis Losana which was synonymized with megacephala by Roger in 1863. Losana also lists a M. megacephala Latrielle in the same publication. Latrielle never described any species by the name megacephala, however. Losana might have instead been referring to Messor megacephala Leech (= Messor barbarous Mayr). Regardless, the original description of M. trinodis states that the species was collected from outdoor gardens. There is some reason to suspect this name might refer instead to P. pallidula, as the only verifiable occurrences of megacephala in Italy since are for specimens collected from plant nurseries, greenhouses and cargo hangars used for holding imported plants, fruits and vegetables (Jucker et al. 2008; Limonta and Colombo 2003). Morocco: Saunders (1888) appears to be the only primary reference for P. megacephala occurring in Morocco, but it is likely that the author was referring to misidentified material of P. pallidula (Wetterer 2012). This view is further evidenced by Cagniant and Espadaler (1993) who were unable to find the species in their survey. Spain: We consider the following records from the Balearic Islands and Gibraltar to refer to P. pallidula (Saunders 1888; Saunders 1904; Walker 1889). USA: The specimens reported in Fischer and Fisher (2013) from Arizona were from a quarantine collection intercepted from Florida, and there is no reason to believe the species has ever established in Arizona. Wetterer (2012) cited a specimen record of P. megacephala from Catalina Island (California). If the identification proves accurate, it is the only known record from that island and the population has since been extirpated (perhaps by L. humile). However, a population (CASENT0248690) has been discovered recently in southern California (Orange Co.). Although P. megacephala is listed in the Missouri Ants web page (2015), we cannot verify the entry with any specimen or literature record.