Simopone Forel, 1891

Borowiec, Marek L., 2016, Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae), ZooKeys 608, pp. 1-280 : 166-170

Taxon classification Animalia Hymenoptera Formicidae

Simopone Forel, 1891

Type-species.

Simopone grandidieri , by monotypy.

Simopone is a genus of arboreal predators of other ants, found in the Old World tropics.

Diagnosis.

Worker. Workers of Simopone are unique among all dorylines in the combination of 11-segmented antennae, eyes and ocelli present, no spur on mid tibia, and the lack of metatibial gland. Simopone also possess a conspicuous groove on the interior surface of hind basitarsus. Other dorylines lacking mid tibial spur include certain species of Lioponera , all Tanipone , and Vicinopone . All these genera have 12-segmented antennae.

Male. The males are easily identified by a combination of antennal sockets partially concealed by the torulo-posttorular complex in full-face view, 12-segmented antennae, presence of notauli, and lack of spurs on middle tibiae. The only other non-army ant doryline genus that lacks spurs on middle tibiae is Tanipone , although it is possible that Vicinopone males will turn out to lack them also, when discovered. All Tanipone males known thus far have fully exposed antennal sockets, 13-segmented antennae, and no notauli, in addition to characteristically long maxillary palps that reach the occipital foramen.

Description.

Worker.Head: Antennae with 11 segments. Apical antennal segment not enlarged, not broader and longer than two preceding segments combined. Clypeus without cuticular apron. Lateroclypeal teeth absent. Parafrontal ridges absent or reduced. Torulo-posttorular complex horizontal. Antennal scrobes absent or present. Labrum with median notch or concavity. Proximal face of stipes projecting beyond inner margin of sclerite, concealing prementum when mouthparts fully closed. Maxillary palps 6- or 5-segmented. Labial palps 4- or 3-segmented. Mandibles triangular, edentate. Eyes present, composed of more than 20 ommatidia. Ocelli present. Head capsule without 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 often separated from collar by distinct ridge, occasionally ridge absent. Promesonotal connection with Pronotomesopleural suture present, weakly differentiated, immobile. Pronotomesopleural suture visible, unfused up to notal surface. Mesometapleural groove weakly impressed or not impressed. Transverse groove dividing mesopleuron absent or present. Pleural endophragmal pit concavity present. Mesosoma dorsolaterally immarginate. Metanotal groove on mesosoma absent or shallowly impressed but well-defined line. Propodeal spiracle situated low on sclerite. Propodeal declivity often without distinct dorsal edge or margin but occasionally marginate, rectangular in posterior view. Metapleural gland without bulla visible through cuticle. Metapleural gland with bulla visible through cuticle. Propodeal lobes present, well developed. Metasoma: Petiole anterodorsally immarginate or marginate, dorsolaterally immarginate, and laterally above spiracle marginate. Helcium in relation to tergosternal Pronotomesopleural suture placed at posttergite and axial. Prora simple, not delimited by carina, a U-shaped margin, or U-shaped margin with median ridge. 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, not sculptured. 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 abdomi nal segments V and VI absent. Girdling constriction between pre- and poststernites of abdominal segments V and VI absent. Pygidium large, with impressed medial field, armed with modified setae, and in some species deeply notched at apex. Hypopygium unarmed. Legs: Mid tibia without spurs. 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 present. Hind pretarsal claws each armed with a tooth. Polymorphism: Monomorphic.

Male.Head: Antennae with 12 segments. Clypeus without cuticular apron. Parafrontal ridges present. Torulo-posttorular complex horizontal. Maxillary palps 6- or 5-segmented. Labial palps 4- or 3-segmented. Mandibles triangular, edentate. Ventrolateral margins of head without lamella or ridge extending towards mandibles and beyond carina surrounding occipital foramen. Carina surrounding occipital foramen ventrally absent. Mesosoma: Pronotal flange separated from collar by distinct ridge. Notauli present. Transverse groove dividing mesopleuron absent. 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 posttergite and axial. 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 shorter ventrally than dorsally. Basimere broadly fused to telomere, with no sulcus trace at junction, and ventrally with left and right arms separated. Telomere expanded at apex. Volsella variable. Penisvalva laterally compressed, rounded at apex. Legs: Mid tibia without spurs. 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 each armed with a tooth. Wings: Tegula present, broad, demiovate in shape. Vein C in fore wing absent. Pterostigma broad. Abscissa R·f3 absent. 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 or absent. Abscissae Rs·f4-5 present, fused in absence of 2rs-m. Abscissa M·f2 in fore wing present, separated from Rs+M by Rs·f2. Abscissa M·f4 in fore wing present, reaching wing margin. Cross-vein 1m-cu in fore wing present or absent. 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 unknown. Abscissa Rs·f2 in hind wing unknown. Cross-vein 1rs-m in hind wing present, about as long as M·f1, never tubular. 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 present. Vein A in hind wing with abscissae A·f1 and A·f2 present.

Gyne. Alate or extremely ergatoid/ replaced by fertile workers. Alate and dealated queen specimens are known in all three Simopone species-groups recognized by Bolton and Fisher (2012), e.g. in Simopone annettae of the schoutedeni group, Simopone latiscapa of the emeryi group, and Simopone bakeri of the grandidieri group. Members of all three species-groups occur also on Madagascar. However, no morphologically distinct gynes have ever been collected among the 16 species occurring on the island, despite multiple nest samples available. It is possible that queens have been replaced there by reproductively active workers, the so-called gamergates ( Bolton and Fisher 2012).

Larva. Not described. Cocoons absent.

Distribution.

Simopone is limited to the Old World and currently contains 39 named species. Most occur in Madagascar and in the Afrotropics but five rare species have been recorded from the Indomalayan Region (China, Thailand, Vietnam, Singapore, Philippines) and New Guinea.

Taxonomy and phylogeny.

Bolton and Fisher (2012) revised and keyed all species in the Afrotropical and Malagasy regions. They also classified Simopone species into three groups based on morphology, but it is unknown whether these are monophyletic. The phylogenetic position of Simopone is not well understood ( Brady et al. 2014, Borowiec, in prep.).

Biology.

Despite relatively high species diversity very little is known about the biology of Simopone , although several species have been recorded nesting arboreally ( Brown 1975, Bolton and Fisher 2012). One species, the Madagascan Simopone sicaria , was observed during a raid. The ants took the brood of arboreal Terataner alluaudi as prey ( Bolton and Fisher 2012).

Brood production appears not to be synchronized ( author’s observations).

Species of Simopone

Simopone amana Bolton and Fisher, 2012: Gabon

Simopone annettae Kutter, 1976: Cameroon

Simopone bakeri Menozzi, 1926: Singapore

Simopone brunnea Bolton and Fisher, 2012: Gabon

Simopone chapmani Taylor, 1966: Philippines

Simopone conradti Emery, 1899b: Cameroon

Simopone consimilis Bolton and Fisher, 2012: Madagascar

Simopone dignita Bolton and Fisher, 2012: Madagascar

Simopone dryas Bolton and Fisher, 2012: Kenya

Simopone dux Bolton and Fisher, 2012: Madagascar

Simopone elegans Bolton and Fisher, 2012: Madagascar

Simopone emeryi Forel, 1892b: Madagascar

Simopone fera Bolton and Fisher, 2012: Madagascar

Simopone fulvinodis Santschi, 1923b: Democratic Republic of the Congo

Simopone grandidieri Forel, 1891: Madagascar

Simopone grandis Santschi, 1923b: Democratic Republic of the Congo

Simopone gressitti Taylor, 1965: Indonesia (Papua)

Simopone inculta Bolton and Fisher, 2012: Madagascar

Simopone laevissima Arnold, 1954: Uganda

Simopone latiscapa Bolton and Fisher, 2012: Ghana

Simopone marleyi Arnold, 1915: South Africa

Simopone matthiasi Kutter, 1977: Cameroon

Simopone mayri Emery, 1911: Madagascar

Simopone merita Bolton and Fisher, 2012: Madagascar

Simopone miniflava Bolton and Fisher, 2012: Gabon

Simopone nonnihil Bolton and Fisher, 2012: Madagascar

Simopone occulta Bolton and Fisher, 2012: Gabon

Simopone oculata Radchenko, 1993: Vietnam

Simopone persculpta Bolton and Fisher, 2012: Kenya

Simopone rabula Bolton and Fisher, 2012: Tanzania

Simopone rex Bolton and Fisher, 2012: Madagascar

Simopone schoutedeni Santschi, 1923b: Democratic Republic of the Congo

Simopone sicaria Bolton and Fisher, 2012: Madagascar

Simopone silens Bolton and Fisher, 2012: Madagascar

Simopone trita Bolton and Fisher, 2012: Madagascar

Simopone vepres Bolton and Fisher, 2012: Ghana

Simopone victrix Bolton and Fisher, 2012: Madagascar

Simopone wilburi Weber, 1949a: Democratic Republic of the Congo

Simopone yunnanensis Chen, Zhou and Liang, 2015: China