Comprehensive DescriptionRead full entry
> Phyracaces HNS Emery, 1902: 23. Type: Cerapachys mayri HNS , by original designation. ----- 1911: 10 - 11, pl. 1, fig. 3, [[ worker ]] [[ queen ]], diagnosis, species list. Synonym of Lioponera HNS , teste Brown and Taylor, 1970: 957 - 958; synonym of Cerapachys HNS , teste Brown, 1973: 181.
> Phyracaces HNS : Wheeler, 1918: 215 - 216, discussion of affinities, etc.; 220 - 223, generic characters, distribution, ethology; 239 - 263, figs. 7 - 17, descriptions, review and key to species of Australia. ----- 1922: 22.
[[ queen ]] [[ male ]] biology, 8 Australian species described. ----- 1930: 3 - 6, 3 Australian spp. described. ----- 1934: 22 - 27, 6 Australian spp. described. ----- 1941: 71, 74 - 76, 2 Australian spp. described.
> Chrysapace Crawley HNS , 1924: 380 - 383, " apterous female, " recte [[ worker ]] or ergatoid [[ queen ]]. Type: Chrysapace jacobsoni HNS , by original description, monobasic. Synonym of Cerapachys HNS , teste Brown, 1973: 179.
There has been a good deal of confusion about the gender of the name Cerapachys HNS . Actually, words in Greek for " horn " containing the stem equivalent of ker- occur in all 3 genders, masculine, feminine and neuter. Keras is the neuter form, and heros HNS is the masculine form. When Smith named the genus, he seems to have been a bit careless in using an " a " instead of an " o " for the fourth letter, but his original employment of the name as masculine is clear from the masculine ending given to the name of the type species (antennatus) in adjectival form. Thus, there seems to be little room for argument, other theories (Borgmeier 1957) notwithstanding, and we should regard Cerapachys HNS as masculine.
Worker: With characters of tribe. Postpetiolar segment (true abdominal segment III) strongly constricted from body of gaster and varying greatly from species to species in size relative to petiole and to true abdominal segment IV, which always is the largest gastric segment. In the more extreme forms of the fragosus HNS and edentatus HNS groups, the petiole and postpetiole form 2 nodes that are small in comparison to segment IV, which covers and forms most of the gaster as in most Myrmicinae HNS . (Compare figs. 91 and 95). No strong constriction between principal gastric segments.
Antennae 9 - 12 segmented, often with a swollen apical segment. Palpi segmented 4,3 to 2,2. Compound eyes varying from large and multifacetted to completely absent. Ocelli present in workers in a minority of species.
Tibial spurs on middle legs; tarsal claws simple or with a submedian tooth.
Queen: Usually winged, but sometimes wingless and ergatoid, always with compound eyes present so far as known, though they may be very small. Characters otherwise as in the worker of the same species, but body usually a little broader, segment for segment. Wings, when present, like those of male.
Male: See characterization under tribe Cerapachyini HNS (p. 15). So far as known, the male of Cerapachys HNS always has 13 - merous antennae and apical spurs on the midtibiae, and the mandibles are triangular, though often with acute apex and concave masticatory border. A sampling of genital capsules is shown in figs. 123 - 126, and subgenital plates in figs. 115, 116, 118, and 122.
In the discussion that follows, I shall show that the synonymy of Cerapachys HNS extends very widely — much more widely, in fact, than I would have believed before I began this study. Nevertheless, all but one of the generic or subgeneric names here listed as synonyms of Cerapachys HNS were based on species originally included in Cerapachys HNS , or early assigned to Cerapachys HNS s. lat. by Emery or Forel. Thus in a sense we are returning to an earlier generic concept.
The 4 subgenera of Cerapachys HNS were based primarily on the number of antennal segments, thus: Cerapachys HNS s. str., 12 segments; Parasyscia HNS , 11; Ooceraea HNS , 10; and Syscia HNS , 9. The subgenus Cysias HNS had already been synonymized under Syscia HNS by Emery (1911: 10).
The series Cerapachys HNS s. str. — Syscia HNS formed a rough morphocline, not only in the decline of antennal segment number from 12 to 9, but also in the loss of eyes in the worker, and in the reduction of the postpetiolar segment and relative increase in dominance of the succeeding (first gastric) segment. The most extreme result of these trends is seen in such Syscia HNS species as edentatus HNS and biroi HNS , in which the petiole and postpetiole are similar in size, and the succeeding segment, true abdominal tergum IV, is enlarged to cover most of the gastric dorsum (fig. 95). This arrangement is formally like that of the subfamily Myrmicinae HNS , and clearly represents a convergence to the myrmicine condition. It also renders very difficult the use of " waist " characters for the separation of formicid subfamilies in classifications and keys, especially when one has to distinguish certain army ants with 2 - segmented waists from cerapachyines and myrmicines.
While the general morphocline in species-groups of Cerapachys HNS involves reductions in both eye size (ommatidial count) and antennomere number, the reductions do not occur with complete concordance. Undescribed species with 12 antennomeres and dot-like eyes in the worker have been found in Africa and Asia, and in these same two continents we have large-eyed species (e. g., nitidulus HNS ) with 11 antennomeres. C. kodecorum HNS new species from southeastern Kalimantan (Borneo) usually has 11 segments in the worker, but one worker from the same series has 7 or even only 6 abnormally thick segments in the funiculus. Who is to say really what is normal and abnormal in antennal segmentation in this genus?
In some 11 - segmented species, the basalmost ring segments are often exceedingly short and indistinct, especially the first segment after the pedicel. This segment may even be largely hidden inside the pedicel, and may be partly fused with the succeeding segment (funiculus III). I believe that subgenus Ooceraea HNS , based on 2 supposedly decamerous species, is actually cryptically 11 - merous. At least, the type and other specimens of 0. fragosus HNS  seem to me to be obscurely 11 - merous, but when the ambiguities of counting and of determining which segments are fused or partly fused become this great, antennal segment number has weakened taxonomic value. Borgmeier (1957: 107), and after him Kempf (1972: 7), apparently hold the same opinion. C. fragosus HNS and relatives from Asia, described and undescribed, are so much like the 9 - segmented C. typhlus HNS group (" subgenus Syscia HNS ") in body form, sculpture, and postpetiolar-gastric proportions that it seems absurd to recognize Syscia HNS merely on the flimsy antennal segment character.
The main characters supposed to separate Phyracaces HNS and Lioponera HNS from Cerapachys HNS are the proportions of the segments near the end of the antenna, and the shape of the petiolar node. In Cerapachys HNS , the apical antennomere is usually very long and thick, even egg-shaped, and can be said to form a club of a single segment. While there can be no denying that many species fit the Cerapachys HNS antennal pattern, others do so less well. The antennatus group (including antennatus, type species of Cerapachys HNS ), for example, shows wide variation in this character, tending to bridge the gap between the Cerapachys HNS condition, with a very thick apical segment, and the Phyracaces HNS condition, in which the apical segment is little or not at all thicker than the penultimate segment.
The 5 - merous club cited as a character of Lioponera HNS seems to me completely ambiguous, as already discussed above. We also have such " bridging " species as C. crawleyi HNS  and C. lividus HNS . Figures 87 - 90 illustrate the CerapachysLioponera-Phyracaces morphocline for antennal clubbing.
The character involving the petiolar node really boils down to whether the node is margined on the sides above. Phyracaces HNS species usually have strong dorsolateral margins on petiole and trunk, and the margination often extends to the postpetiole and even, in a few Australian species, to the head behind the eyes. Thus one finds a morphocline for strength and extent of margination along the body axis within Phyracaces HNS , and this morphocline stretches of course into Lioponera HNS (C longitarsus group), which has only the petiolar node laterally marginate. Here again the antennatus complex of forms provides a bridge between Cerapachys HNS and Phyracaces HNS , because in this complex, the petiole can be more or less Phyracaces-like or Cerapachyslike in different-sized individuals of the same nest series. I have pointed out in the discussion of this group  that one species was originally described as " Phyracaces vandermeermohri HNS " which illustrates the ambiguity of the generic lines here. In addition to the antennatus group, we have the annectant forms crawleyi HNS , pruinosus HNS , and lividus HNS . Had the last-named species been earlier described from Australia instead of Madagascar, I believe it would have been put into Phyracaces HNS rather than Cerapachys HNS .
The ambiguity of the margination as a generic character is also demonstrated in the descriptions of such species as Phyracaces pygmaeus HNS and P. aberrans HNS [33, 47] (Clark, 1934: 25 - 27) and P. braytoni HNS (Weber, 1949: 3). I have examined the type of P. braytoni HNS , and find it to be a member of the same species-group as Lioponera longitarsus HNS , type species of that genus, and P. pygmaeus HNS is actually a synonym of longitarsus HNS . R. W. Taylor recognized independently (personal communication) that Lioponera HNS was nothing more than an indistinct species-group within Phyracaces HNS , and we accordingly tacitly synonymized the latter in our contribution to " The Insects of Australia " (Brown and Taylor, 1970). The name Lioponera HNS , being older, or course then took priority over Phyracaces HNS . The members of the longitarsus HNS group are, so far as we know, arboreal or subarboreal dwellers in hollow twigs and perhaps other tubular cavities in wood or bark, a microhabitat in consonance with the workers' slender, cylindrical body build and large compound eyes. I assume that they prey on ants of other species occupying similar habitats, but there is no real information available on their feeding habits. Both Lioponera HNS and Phyracaces HNS axe treated as synonyms of Cerapachys HNS in Brown (1973: 181).
Clark (1941) raised a genus Neophyracaces HNS for a group of Australian species in which the workers normally possess ocelli. Most of these species are relatively large in size and prevailingly bright orange or reddish ferruginous in color, and they seem especially well adapted to xeric conditions. Otherwise, they conform to the " typical " Phyracaces HNS pattern, with strongly developed margination of the trunk, petiole, and even the postpetiole. A number of Phyracaces HNS species in Australia are like them, except that the workers lack ocelli. Elsewhere in the collective genus Cerapachys HNS — as in the complexes of C. antennatus HNS  and C. fragosus HNS  — the appearance of ocelli is an allometric character within as well as between colony series. Some of the large, ocellate individuals may in fact be functional reproductives (ergatoids), even in species known to possess dealate queens, but at present we have no direct information on this matter. In view of our scanty and largely ambiguous knowledge of ocellar occurrence and function in Cerapachys HNS s. lat., it does not seem to me that Clark's Neophyracaces HNS is worthy of recognition as more than a species-group within Cerapachys HNS . It would be interesting to know whether and to what extent the ocellate workers of this group also function as reproductives.
C. crawleyi HNS illustrates one method of dealing with annectant species: make it the type of a new genus. This species was originally described by Crawley as Chrysapace jacobsoni HNS ( Chrysapace HNS , like Phyracaces HNS , is an anagram of Cerapachys HNS ). While the species  is aberrant in its own right, it fits fairly comfortably in either Cerapachys HNS or Phyracaces HNS as they have been constituted in recent years, and Wheeler (1924) doubted that it was outside of Cerapachys HNS . However, C crawleyi HNS has one very primitive character in addition to its striking sculpture: the middle and hind tibiae each have a large and a small apical spur. The evidently related species C. sauteri HNS has not been examined for the spur character, but if the tibiae in this poorly known Taiwanese species also have 2 spurs each, it may be necessary to resurrect Chrysapace HNS as a genus.
We still have to account for the genus Simopone HNS . Although described by Forel in 1891 as a genus, Simopone HNS was placed as a subgenus of Cerapachys HNS by its author in the following year, but Emery's 1911 treatment of it as a genus set apart in a special tribe with Cylindromyrmex HNS tended to obscure the early relationship. Most of the species subsequently described in Simopone HNS tended to strengthen the concept of a separate genus; the 11 - merous antennae, large, flat eyes, presence of ocelli, and above all, the separated frontal carinae, often framing demiscrobes for the antennae, tended to mark off a presumably arboreal group of species with its own distinctive habitus. However, the central African species grandis HNS  is not so typical, and the fact that it combines traits of Cerapachys HNS and Phyracaces HNS with those of more characteristic Simopone HNS species was obscured by a mediocre original description and by the paucity and isolation of material available for study in collections. The discovery and analysis of another specimen of grandis HNS  permits us now to say that it is such a strong link between Simopone HNS and Cerapachys HNS s. lat. that the generic distinction comes into doubt.
Further trouble for this distinction comes in the form of a new species, Simopone conciliatrix HNS , Simopone-like in habitus, but with 12 antennomeres and other details that put it in the category of annectants between Simopone HNS and Cerapachys HNS . Of course, there exist species of Cerapachys HNS with 11 antennomeres (subgenus Parasyscia HNS ), but, as already discussed, they mostly have the eyes reduced or absent, rather than enlarged as in Simopone HNS . Thus the 11 - merous condition in Simopone HNS and Parasyscia HNS has apparently been considered (by anyone who may have thought about it at all) as convergent. The new 12 - merous species now ties Simopone HNS back to the more primitive line of Cerapachys HNS , which (according to Williston's Rule) must have had 12 antennal segments. Williston's Rule may also be invoked in the matter of the maxillary and labial palpi, which in C. grandis HNS have 6 and 4 segments respectively, but in C. conciliatrix HNS only 3 and 2. We see here the expression of an interesting tendency in ants as a family to maintain high palpal counts among some epigaeic, and especially arboreal, foragers. In these same lines, however, antennal segments may either be reduced in number, or stay at the primitive number 12.
In the circumstances, my instincts have been to place Simopone HNS in the synonymy of Cerapachys HNS as a primitive arboreal group of the latter genus, and this is the way the situation may well be viewed by future revisers. There does, however, remain one character by which the two groups can still be unequivocally separated in at least the workerqueen castes, and that is the tibial spur of the middle leg — present in all Cerapachys HNS I have examined, and absent in Simopone HNS . Since the middle-leg spur character is concordant in a rough way with the traditional characters of Simopone HNS , it seems best to continue to recognize the generic separation, a course that also avoids some awkward specieslevel homonymy that would result if the Simopone HNS species were thrown into Cerapachys HNS .
bionomics: Discussed previously under the tribe.
distribution: Cerapachys HNS as here constituted is by far the largest genus in the tribe, and its geographical range is virtually coextensive with that of tribe Cerapachyini HNS . The genus is much better represented in the Old World than the New, and the majority of species, both described and undescribed, are in the Indo-Australian region. Forms with laterally marginate petiole (formerly Phyracaces HNS , Neophyracaces HNS , and Lioponera HNS ) are restricted to the Old World, and have radiated especially extensively in Australia, where they occur in semidesert as well as wet and dry forest habitats. The 9 - segmented group ( Syscia HNS ) is widespread in northern and eastern Australia as one or two species , and also has endemic species in New Guinea, the Solomons and Fiji; s. biroi HNS of this group has become established in Hawaii and even in the West Indies, following probable overseas transport by human commerce. The 9 - segmented species are good colonizers.
It is interesting to note that the " more typical " Cerapachys HNS — the species with rounded petiole and 12 or 11 antennal segments related to C. dohertyi HNS and C. cribrinodis HNS — have not penetrated continental Australia, though they have spread through Melanesia as far eastward as Fiji. This absence may be related to the extraordinary radiation in Australia of Sphinctomyrmex HNS in the adaptive zones that elsewhere are mainly occupied by Cerapachys HNS .
In the New World, where Sphinctomyrmex HNS is known only from a single rare, localized species, Cerapachys HNS is represented sparsely by a few 11 - segmented species ranging from Sonoran North America southward to Panama; one 11 - segmented species apparently isolated in southeastern Brasil; and one 12 - segmented, minute-eyed species from Trinidad that possibly could be a historic immigrant like C. biroi HNS , known from the same island. The 11 - merous species from North and Central America appear to be endemic, and number perhaps as many as 5 or 6, counting undescribed samples; these form a tightly knit group of blind or minute-eyed forms related to C. augustae HNS . It seems likely that Cerapachys HNS is limited in the New World by competition with myrmecotherous ecitonines such as Neivamyrmex HNS .
In Africa, Cerapachys HNS is widely and fairly well represented by a diversity of groups of species with 11 or 12 antennal segments (mainly 12) in habitats ranging from rain forest to arid karroo veld, montane grassland, and Saharan oases and wadis. Although at least one species ( C. piochardi HNS ) occurs in the Middle East, no cerapachyine is known to reach Europe.
Cerapachys HNS ranges to the southern shores of Australia and South Africa, and is well represented on Madagascar, but is still unknown from south of Brasil in South America. In Asia, the genus reaches north to the Himalayan wall, central China, and southern Japan.