Cerapachys

Once believed to be a diverse genus with a pantropical distribution, the Dorylinae revision of Borowiec (2016) shows this name applies to a relatively species-poor lineage that is apparently restricted to forest habitats of Southeast Asia.

Identification
Borowiec (2016) - Worker Cerapachys belongs to non-army ant dorylines with spiracle positioned below midheight of the propodeum and pygidium well-developed, armed with modified setae. It has a well-developed carina on the pronotal collar and a distinct pronotomesopleural suture, a single pectinate spur on each mid and hind tibia, and helcium positioned supraaxially, above midheight of abdominal segment III. Some species have pretarsal claws armed with a tooth. Cerapachys is a genus of medium-sized, universally dark-colored ants that could be confused Lividopone. Distributions of the two genera do not overlap, however, with Lividopone being so far known only from Madagascar. Lividopone is further distinguished by almost complete fusion of pronotomesopleural suture, which is unfused in Cerapachys. Lioponera overlaps in range with Cerapachys and certain species can be superficially similar but a more narrow and axially positioned helcium, dorsolaterally carinate petiole, and a flange on the posterior face of the coxae will distinguish Lioponera.

Male The male of Cerapachys has 12-segmented antennae, a transverse groove running diagonally across the mesopleuron, vein C in fore wing present, one submarginal cell closed by Rs·f2–3, 2rs-m absent, and marginal cell closed by R·f3 and Rs·f4–5. Neocerapachys males have similar wing venation but in Cerapachys the antennal segment III is similar in length to segment IV, while in Neocerapachys the segment III is conspicuously the shortest antennal segment. Furthermore, Neocerapachys is only found in the New World.

Distribution
Cerapachys is distributed from northwestern India and Tibet, through southern China to Java, Borneo and the Philippines. (Borowiec 2016)

Fossils
Fossils are known from: (an unidentified species, Wang et al., 2021).

Biology
Borowiec (2016) - Almost nothing is known about the biology of this group. Most records seem to come from forest habitats. Brood development may be synchronized, based on the author’s observation of brood of uniform size in the single examined nest collection of Cerapachys antennatus.

Worker Morphology
Borowiec (2009) used the following terms in his revision of the Cerapachys sexspinus species group;

The term ‘parafrontal ridges’ is derived from Wilson’s (1964) work on Aenictus, and is used for low lines running from lateral portions of clypeus laterad to antennal sockets, thus separating them from the genae. Such ridges are present in most Cerapachyini, but absent in many Sphinctomyrmex, all Acanthostichus and Cylindromyrmex.

‘Lateroclypeal tooth’ is here introduced for the modification of the lateral corners of the clypeus, which in cerapachyines can be variably developed, from being bluntly pointed to drawn into conspicuous teeth that project over the mandibles.

Nomenclature

 *  CERAPACHYS [Cerapachyinae: Cerapachyini]
 * Cerapachys Smith, F. 1857a: 74. Type-species: Cerapachys antennatus, by subsequent designation of Bingham, 1903: 28.
 * Cerapachys senior synonym of Ceratopachys: Wheeler, W.M. 1922a: 755.
 * Cerapachys senior synonym of Parasyscia, Syscia (and its junior synonym Cysias): Kempf, 1972a: 76; Brown, 1975: 18.
 * Cerapachys senior synonym of Chrysapace, Lioponera, Neophyracaces, Ooceraea, Phyracaces, †Procerapachys: Brown, 1975: 18.
 * Cerapachys senior synonym of Yunodorylus: Bolton, 2003: 141, 268.
 *  ORAPACHYS [unavailable name]
 * Orapachys Forel, 1893a: 162, incorrect subsequent spelling of Cerapachys.
 * CERATOPACHYS [junior synonym of Cerapachys]
 * Ceratopachys Schulz, W.A. 1906: 155, unjustified emendation of Cerapachys.
 * Ceratopachys junior synonym of Cerapachys: Wheeler, W.M. 1922a: 755.

Borowiec (2016) - This is the lineage where the type species of Cerapachys, Cerapachys antennatus, belongs. The type series was collected by A. R. Wallace in Sarawak and described by F. Smith in 1857.

Taxonomic Notes
Cerapachys is a member of a predominantly South East Asian clade that also includes Chrysapace and Yunodorylus (Borowiec, 2019).

Worker
Borowiec (2016) - Head: Antennae with 12 segments. Apical antennal segment conspicuously enlarged, much broader than and longer than two preceding segments combined. Clypeus with or without cuticular apron. Lateroclypeal teeth absent. Parafrontal ridges reduced. Torulo-posttorular complex vertical. Antennal scrobes absent. Labrum with median notch or concavity. Proximal face of stipes projecting beyond inner margin of sclerite, concealing prementum when mouthparts fully closed. Maxillary palps 3-segmented. Labial palps 2-segmented. Mandibles triangular, with teeth. Eyes present, composed of more than 20 ommatidia. Ocelli absent. Head capsule with differentiated vertical posterior surface above occipital foramen. Ventrolateral margins of head without lamella or ridge extending towards mandibles and beyond carina surrounding occipital foramen. Posterior head corners dorsolaterally immarginate. Carina surrounding occipital foramen ventrally absent. Mesosoma: Pronotal flange separated from collar by distinct ridge. Promesonotal connection with suture completely fused. Pronotomesopleural suture visible, unfused partway to notal surface. Mesometapleural groove deeply impressed, conspicuous. Transverse groove dividing mesopleuron absent. Transverse groove dividing mesopleuron present. Pleural endophragmal pit concavity present. Mesosoma dorsolaterally immarginate. Metanotal depression or groove on mesosoma present. Propodeal spiracle situated low on sclerite. Propodeal declivity with distinct dorsal edge or margin and rectangular in posterior view. Metapleural gland without bulla visible through cuticle. Propodeal lobes present, well developed. Metasoma: Petiole anterodorsally marginate, dorsolaterally immarginate, and laterally above spiracle marginate. Helcium in relation to tergosternal suture placed at posttergite and supraaxial. Prora forming a V-shaped protrusion. Spiracle openings of abdominal segments IV–VI circular. Abdominal segment III anterodorsally marginate, dorsolaterally immarginate. Abdominal segment III more than half size of succeeding segment IV, which is weakly constricted at presegmental portion (uninodal waist). Girdling constriction of segment IV present, i.e. pre- and postsclerites distinct. Cinctus of abdominal segment IV gutter-like and cross-ribbed. Abdominal segment IV not conspicuously largest segment. Abdominal tergite IV not folding over sternite, and anterior portions of sternite and tergite equally well visible in lateral view. Girdling constriction between pre- and posttergites of abdominal segments V and VI absent. Girdling constriction between pre- and poststernites of abdominal segments V and VI absent. Pygidium large, with impressed medial field, and armed with modified setae. Hypopygium unarmed. Legs: Mid tibia with single pectinate spur. Hind tibia with single pectinate spur. Hind basitarsus not widening distally, circular in cross-section. Posterior flange of hind coxa not produced as raised lamella. Metatibial gland present as oval patch of whitish cuticle. Metabasitarsal gland absent. Hind pretarsal claws simple or each claw armed with a tooth. Polymorphism: Monomorphic to moderately polymorphic.

Queen
Borowiec (2016) - Alate, fully winged with large eyes and three ocelli, or also possibly ergatoid (Brown 1975), larger than worker, with large eyes and three ocelli but no wings.

Male
Head: Antennae with 13 segments. Clypeus with cuticular apron. Parafrontal ridges present. Torulo-posttorular complex vertical. Maxillary palps 5-segmented. Labial palps likely 3-segmented (uncertain in-situ count). Mandibles triangular, edentate or crenulate. Ventrolateral margins of head with cuticular ridge extending towards mandibles and beyond carina surrounding occipital foramen. Carina surrounding occipital foramen ventrally present. Mesosoma: Pronotal flange separated from collar by distinct ridge or not separated. Notauli present. Transverse groove dividing mesopleuron present. Propodeal declivity reduced, with or without distinct dorsal edge or margin. Metapleural gland opening absent. Propodeal lobes present. Metasoma: Petiole anterodorsally immarginate, dorsolaterally immarginate or marginate, and laterally above spiracle marginate. Helcium in relation to tergosternal suture placed at posttergite and supraaxial. Prora forming a V-shaped protrusion. Spiracle openings of abdominal segments IV–VI circular. Abdominal segment III more than half size of succeeding segment IV, occasionally slightly smaller; latter weakly constricted at presegmental portion (uninodal waist). Girdling constriction of segment IV present, i.e. pre- and postsclerites distinct. Cinctus of abdominal segment IV gutter-like, not sculptured or cross-ribbed. Girdling constriction between pre- and postsclerites of abdominal segments V and VI absent. Abdominal segment IV not conspicuously largest segment. Abdominal sternite VII simple. Abdominal sternite IX distally armed with two spines. with lateral apodemes about as long as medial apodeme, directed anteriorly (towards head). Genitalia: Cupula long relative to rest of genital capsule and shorter ventrally than dorsally. Basimere broadly fused to telomere, with sulcus discernable at junction, and ventrally with left and right arms abutting. Telomere gradually tapering toward apex. Volsella gradually tapering toward apex. Penisvalva laterally compressed, rounded at apex. Legs: Mid tibia with single pectinate spur. Hind tibia with single pectinate spur. Posterior flange of hind coxa not produced as raised lamella. Metatibial gland present as oval patch of whitish cuticle. Metabasitarsal glands absent. Hind pretarsal claws each armed with a tooth; simple claws not observed but presumably absent from certain species as in worker. Wings: Tegula present, broad, demiovate in shape. Vein C in fore wing present. Pterostigma broad. Abscissa R·f3 present, running toward distal wing margin and enclosing cell with Rs·f5. Abscissae Rs·f2–3 present, connecting with Rs+M&M·f2. Cross-vein 2r-rs present, differentiated from Rs·f4 by presence of Rs·f2–3. Abscissae Rs·f4–5 present, fused in absence of 2rs-m. Abscissa M·f2 in fore wing contiguous with Rs+M or separated from Rs+M by Rs·f2. Abscissa M·f4 in fore wing present, not reaching wing margin to almost reaching wing margin. Cross-vein 1m-cu in fore wing present. Cross-vein cu-a in fore wing present, arising from M+Cu and proximal to M·f1. Vein Cu in fore wing present, with both branches Cu1 and Cu2. Vein A in fore wing with abscissae A·f1 and A·f2 present. Vein C in hind wing absent. Vein R in hind wing absent. Vein Sc+R in hind wing present. Abscissa Rs·f1 in hind wing present, shorter than 1rs-m. Abscissa Rs·f2 in hind wing present, not reaching wing margin. Cross-vein 1rs-m in hind wing fused with M·f1. Vein M+Cu in hind wing present. Abscissa M·f1 in hind wing present. Abscissa M·f2 in hind wing present. Cross-vein cu-a in hind wing present. Vein Cu in hind wing absent. Vein A in hind wing with abscissae A·f1 and A·f2 present.

Larva
Not described. Cocoons absent.