Lividopone Fisher & Bolton, 2016

Borowiec, Marek L., 2016, Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae), ZooKeys 608, pp. 1-280 : 136-138

Taxon classification Animalia Hymenoptera Formicidae

Lividopone Fisher & Bolton, 2016

Type-species.

Cerapachys lividus , by subsequent designation.

This relatively speciose lineage includes species nesting in a variety of substrates, from soil to twigs. It is known that they prey on brood of other ants.

Diagnosis.

Worker. The workers of Lividopone are recognized by a combination of 12-segmented antennae, pronotomesopleural Pronotomesopleural suture fused, propodeal spiracle positioned low and presence of propodeal lobes, pygidium large and armed with modified setae, helcium broad and positioned supraaxially on the sclerite, middle tibiae with a single pectinate spur, and pretarsal claws simple. Cerapachys is similar in general habitus but it is easily differentiated because of its unfused pronotomesopleural Pronotomesopleural suture. Parasyscia , certain Lioponera and Simopone may have a similar habitus but those genera never have a broad, highly positioned helcium.

Male. The male of Lividopone shares the broad supraaxial helcium with the worker caste, which makes it easy to distinguish from any other doryline when combined with well-developed propodeal lobes, antennal toruli exposed in full-face view, one spur on each mid and hind tibia, and no C or R·f3 veins in the fore wing. Males of Lividopone can potentially be confused with Lioponera and Parasyscia which also lack veins C and R·f3 and with which it co-occurs, but the highly broad positioned helcium alone can distinguish it from those two lineages.

Description.

Worker.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 or edentate. 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. Ventrolateral margins of head with cuticular ridge extending towards mandibles and beyond carina surrounding occipital foramen. Posterior head corners dorsolaterally immarginate. Carina surrounding occipital foramen ventrally absent or present. Mesosoma: Pronotal flange separated or not from collar by distinct ridge. Promesonotal connection with Pronotomesopleural suture completely fused. Pronotomesopleural suture completely fused. Mesometapleural groove deeply impressed, conspicuous. Transverse groove dividing mesopleuron present. Pleural endophragmal pit concavity present. Mesosoma dorsolaterally immarginate. Metanotal depression or groove on mesosoma absent. Propodeal spiracle situated low on sclerite. Propodeal declivity with or without 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 immarginate, dorsolaterally immarginate, and laterally above spiracle marginate. Helcium in relation to tergosternal Pronotomesopleural suture placed at posttergite and supraaxial. Prora forming a simple U-shaped margin or V-shaped protrusion. Spiracle openings of abdominal segments IV–VI circular. Abdominal segment III anterodorsally immarginate and 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, and in some species deeply notched at apex. 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 absent. Metabasitarsal gland absent. Hind pretarsal claws simple. Polymorphism: Monomorphic.

Male.Head: Antennae with 13 segments. Clypeus with cuticular apron. Parafrontal ridges present. Torulo-posttorular complex vertical. Maxillary palps unknown. Labial palps unknown. Mandibles triangular, edentate. Ventrolateral margins of head with cuticular ridge extending towards mandibles and beyond carina surrounding occipital foramen. Carina surrounding occipital foramen unknown. Mesosoma: Pronotal flange separated from collar by distinct ridge. Notauli present. Transverse groove dividing mesopleuron present. Propodeal declivity with distinct dorsal edge or margin. Metapleural gland opening absent. Propodeal lobes present. Metasoma: Petiole anterodorsally marginate, dorsolaterally immarginate, and laterally above spiracle marginate. Helcium in relation to tergosternal Pronotomesopleural suture placed at Pronotomesopleural suture and supraaxial. Prora forming a U-shaped protrusion. Spiracle openings of abdominal segments IV–VI circular. Abdominal segment III more than half size of succeeding segment IV; 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 and 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 of approximately equal length on both dorsal and ventral surfaces. 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 constricted basally, distally a widening to narrow triangle, serrated ventrally. 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 absent. Metabasitarsal glands absent. Hind pretarsal claws simple. Wings: Tegula present, broad, demiovate in shape. Vein C in fore wing absent. Pterostigma broad. Abscissa R·f3 ab sent. Abscissae Rs·f2-3 present, connecting with Rs+M&M·f2 or more rarely absent. Cross-vein 2r-rs absent or present, forming base of 'free stigmal vein’ (2r-rs&Rs·f4-5) in absence of Rs·f3 and 2rs-m, or (most commonly) present, differentiated from Rs·f4 by presence of Rs·f2-3. Abscissae Rs·f4-5 absent or more often present, fused in absence of 2rs-m. Abscissa M·f2 in fore wing absent or present, separated from Rs+M by Rs·f2. Abscissa M·f4 in fore wing absent or a stub. Cross-vein 1m-cu in fore wing absent or present. Cross-vein cu-a in fore wing absent or fore wing present, arising from M+Cu and proximal to M·f1. Vein Cu in fore wing present, with only Cu1 branch prominent. Vein A in fore wing absent or 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 absent. Abscissa Rs·f1 in hind wing absent or present, longer than 1rs-m. Abscissa Rs·f2 in hind wing absent or stub present. Cross-vein 1rs-m in hind wing absent or present, about as long as M·f1. Vein M+Cu in hind wing absent or present. Abscissa M·f1 in hind wing absent or present. Abscissa M·f2 in hind wing absent or present. Cross-vein cu-a in hind wing absent. Vein Cu in hind wing absent or present. Vein A in hind wing absent.

Gyne. Alate with large eyes and ocelli or ergatoid. The latter variously developed, from forms possessing flight-associated mesosomal sutures but no wings to extremely worker-like, without ocelli and of similar size, with only erect pubescence distinguishing the gyne from worker. In some species intercastes occur in addition to alate gynes (Barry Bolton pers. comm.).

Larva. Not described. Cocoons are present.

Distribution.

This group is relatively species-rich with only one named species but some 30 more species awaiting description. The genus appears to be restricted to Madagascar.

Taxonomy and phylogeny.

Brown (1975) described Cerapachys lividus from Madagascar, for which the name Lividopone was recently proposed ( Fisher and Bolton 2016).

Lividopone is sister to the Zasphinctus plus Parasyscia clade ( Brady et al. 2014, Borowiec, in prep.).

Biology.

Brown (1975) observed about 20 workers of Lividopone livida raiding a Pheidole nest in a rainforest habitat. I discovered a nest of Lividopone in a dead log in mid-elevation forest, containing only about 15 workers, one dealate gyne and no brood. Similarly small colonies were recorded for an undescribed arboreal Lividopone . All four nests of that species I collected were in hollow twigs situated above forest floor. These colonies each contained multiple apparent gynes, which were extremely worker-like and differed from other individuals only in conspicuously erect pilosity. One of the colonies contained brood of Monomorium termitobium as prey. This arboreal species also apparently synchronizes brood production and nest samples containing brood of the same stage of development are known for Lividopone livida and other undescribed species ( author’s observations)

Species of Lividopone

Lividopone livida (Brown, 1975): Madagascar