Worker.-Small or medium-sized, slender, monomorphic, opaque black ants, with pruinose surface and very poorly developed pilosity, with flat clypeus often without a posterior suture, indistinct frontal area and large, thick, expanded and widely separated frontal carinae. Mandibles large, triangular, with edentate or finely denticulate apical border. Maxillary palpi 6-jointed, labial palpi 4-jointed. Antennae stout, funiculi without a distinct club. Eyes rather large; ocelli absent. Premesonotal suture distinct, other thoracic sutures feeble or obsolete. Petiole massive, not squamiform, its posterior articulation at the middle of the anterior surface of the petiole. The constriction between the latter and the gaster moderately pronounced. Middle and hind tibiae with two spurs; claws with a single tooth.
Female winged, very similar to the worker and but little larger; eyes larger, but ocelli not always developed. Pronotum large; mesonotum depressed. Wings with two closed cubital cells, a discoidal cell and a closed radial cell as in many other Ponerinae.
Male more like the female than in most genera of the subfamily; clypeus more convex than in the worker and female; frontal carinae not dilated anteriorly. Mandibles triangular, with sharp apical border. Antennae 13-jointed; scape a little shorter than the second funicular joint. Eyes and ocelli very large. Pronotum large, not overarched by the mesonotum, the latter convex, with indistinct Mayrian furrows. Petiole much as in the worker. Pygidium rounded; cerci developed.
This genus, of which more than 35 species arc; known, ranges oven the tropics of both hemispheres (Map 7) and is represented by more species in Africa and Madagascar than in the Indoaustralian or Neotropical Regions. Our American and many of the African species seem to feed largely or exclusively on termites. I have found P. punctata (Smith) of the West Indies nesting in termitaria. Arnold gives some notes on the habits of two of the African forms. Of P. lamellosa (Roger) subsp. longinoda, Forel variety rhodesiana Forel he says:
The nest of this species is go distinctive that it cannot be mistaken for that of any other Ponerinae. The entrance is surmounted by a dome, from 6 to 8 inches high, by about 12 inches broad at the base. The dome is built up of very even-sized small pebbles, about 5 to 8 mm. in their largest diameter. The entrance is situated in the center above, and this is generally the only entrance, very exceptionally there may be a smaller and less regular opening at the base of the mound.
Map 7. Distribution of the genus Platythyrea .
He gives the following account of P. arnoldi Forel : I have met with this species on only one occasion. The nest, situated on an open piece of ground, was surmounted by a mound with the entrance at the apex, as in lamellosa variety rhodesiana , but unlike that species the mound of arnoldi contains' large pebbles, The surface of the mound was covered with the elytra and carcasses hundreds of beetles, mostly Tenebrionidae. Workers were seen carrying live [[...]] to the nest, the prey being held by its mandibles in a position above and part of the body of the ant. Since a careful examination of the rubbish-heap of [[...]] failed to show the remains of other insects, it is probable that this species feeds entirely on Coleoptera, differing in this respect from most of the other members of the genus, which in Rhodesia, at any rate, are entirely termitophagous.
(Fig. 10)
Males winged. Antennal scrobe distinct. Mandible large, stout, triangular, with many teeth on its masticatory margin, and masticatory margins completely overlap when mandibles are fully closed. Basal cavity of mandible invisible in full-face view. Notauli impressed on mesoscutum. Mesepimeron bearing distinct (epimeral) lobe posterodorsally, lobe covering mesothoracic spiracle and seeming to form isolated plate. Dorsolateral corner of petiole in anterior view lacking distinct projection. Dorsal margin of petiole, in anterior view, broadly or narrowly rounded. Apical margin of abdominal tergum VIII does not project strongly into sharp spine. Jugal lobe of hind wing may or may not be present. Middle and hind tibiae with two spurs. Claws simple, never multidentate or pectinate. Body surface sparsely punctate.
Remarks. This genus is easily separated from other Malagasy ponerine males by the following combination of characters: 1) presence of the antennal scrobe; 2) large, stout, and triangular mandible; 3) two tibial spurs on each middle and hind leg; 4) large eyes; 5) sparse punctures on body surface; 6) standing pilosity sparse or absent; and 7) pruinose appearance.
Der Kopf ist laenglich viereckig, vorn und hinten nur sehr wenig verengt. Der Clipeus geht ohne eine Spur von Grenze in die Stirnlappen ueber. Diese sind ueber der Fuehlerwurzel dreieckig lappenfoermig ausgezogen, konvergiren nach vorn und hinten, and sind wenig aufgebogen, fast horizontal; der Raum zwischen ihnen ist sehr breit and ganz schwach ausgehoehlt. Stirnfeld and Stirnrinne fehlen gaenzlich. Fuehler 12 - gliedrig, die Geisselglieder gegen die Spitze etwas verdickt, alle eng an einander schliessend, Endglied zugespitzt Netzaugen ziemlich in der Mitte. Mandibeln dreieckig, etwa den dritten Theil des Kopfes lang.
Der Thorax ist lang, cylindrisch, oben leicht gewoelbt; das Pronotum ist seitlich schwach gerundet, vom Mesonotum durch einen Quereindruck getrennt. Meso- und Metanotum ganz verwachsen. Die abschuessige Flaeche des letztern ist senkrecht, scharf gerandet, etwas ausgehoehlt und oben (an der Grenze der Basalflaeche) mit 2 weit auseinander stehenden Zaehnchen oder scharfen Ecken versehen.
Schuppe laenger als breit, cylindrisch, dick, oben und seitlich leicht gewoelbt, die Vorderseite schwach konvex, der Hinterrand, der ein wenig breiter als der Vorderrand erscheint, hat seitlich 2 scharfe Ecken; (derselbe kann auch 2 mal ausgerandet sein, wodurch dann, ausser den Seitenecken, auch ein mittlerer Vorsprang gebildet wird).
Das Stielchen ist in der Mitte der Vorderseite des Abdomens eingefuegt.
Die Metatarsen sind viel kuerzer als die Schienen; die Klanen haben in der Mitte oder vorn einen Zahn.
Zu diesem Genus gehoeren Pachycondyla punctata Smith, Pon. sinuata Rog., Pon. lamellosa Rog. and P. cribrinodis Gerstaecker.
> Platythyrea Roger, 1863, Berlin. Entomol. Zeitschr., 7: 172, [[ worker ]]. Type: Platythyrea punctata (F. Smith) , by designation of Bingham, 1903.
> Platythyrea : Emery, 1911: 28 - 30, pl. 2, fig. 1, lb, [[ worker ]] [[ queen ]] [[ male ]] diagnoses, species list. ----- Wheeler, 1922 a: 57 - 60, diagnosis; 1922 c: 758 - 76 l, list of African spp.; 1922 d: 1007, list of Malagasy spp. ----- Wilson, 1958 b: 150 - 153, revision of Melanesian spp. ----- Kempf, 1972: 206, neotropical species list.
[[ ... ]] Ponera : F. Smith, 1858: 95. ----- Gerstaecker, 1859: 262. ----- Roger, 1860: 295.
[[ ... ]] Pachycondyla F. Smith, 1858: 95.
[[ ... ]] Pachycondyla subgenus Bothroponera : Forel, 1913 b: 176.
> Eubothroponera Clark, 1930: 8 - 9, [[ worker ]]. Type: Eubothroponera dentinodis Clark , by original designation. ----- Clark, 1934 a: 32 - 34; designation of E. tasmaniensis as type invalid. ----- Clark, 1938: 361. ----- Brown, 1952: 2 - 5, transfer to Platythyreini , discussion. New synonym.
A diagnosis is given here in side-by-side comparison with that of Probolomyrmex .
PLATYTHYREA
Worker: Size modest to large; TL 4 to about 20 mm.
Antennal insertions remote and roofed by broad horizontal frontal lobes, situated behind clypeus and away from (behind) anterior border of head. Clypeus broad, with lateral wings, nearly flat to strongly convex, with or without a depressed narrow anterior apron. Posterior margin of clypeus varying from fine but distinct, to indistinct, or even absent, so that the surfaces of the posterior clypeus, frontal triangle, and frontal lobes tend to be confluent. Frontal triangle at most weakly impressed, with or without a shallow trailing median sulcus separating the frontal lobes.
Mandibles prominent, exposed, triangular, with distinct masticatory and basal borders, the blades extended but more or less downcurved; masticatory border serially dentate or denticulate, or edentate and cultrate; basidorsal surface with or without an oblique groove running laterapicad to the outer margin. Palpal formula 6, 4 to 3, 2.
Compound eyes always present and multifacetted, modest to large in size, situated near or in front of middle of sides of the head.
Antennal scapes reaching very nearly to or (usually) beyond posterior border of head in full-face view.
Trunk with a complete and apparently flexible promesonotal suture.
Middle and hind tibiae each with 2 (large mesal, smaller lateral) pectinate spurs; tarsal claws usually each with a distinct or indistinct median tooth.
Full adult color ranging from deep yellowish brown to black, the appendages often a contrasting lighter hue.
Queen: Much like corresponding worker in size and form, but winged as virgin and with moderately welldeveloped pterothoracic sclerites. Notauli absent or weak and incomplete. Ocelli present, weak, or even entirely absent; the last a condition otherwise unknown among winged queen ants. Venation complete for ants in both fore and hind wings; anal lobe present in hind wing.
Male: Size nearly that of corresponding workers and queens.
Head broader than long, including large compound eyes (fig. 32). Mandibles triangular, exposed, opposable. Antennal insertions remote and positioned behind a broad, convex clypeus.
Notauli present, usually strong and complete; parapsidal furrows present, fine. Metanotum variable, sometimes with a blunt point. Wings as in queen. Middle and hind legs with bicalcarate tibial apices, tarsal claws each with a median tooth so far as known.
Petiolar node more or less like that of corresponding worker and queen, though posterodorsal margination, teeth, etc. generally less distinct in the males so far known.
Genital capsule retractile, with all primitive parts present and well developed (figs. 131 - 136). Pygidium distinctive, usually tapered toward apex and sometimes produced as a downcurved aculeus. Cerci present and normally exposed (fig. 135).
Afrique orientale anglaise: Voi (600 m., st. no 60, mars 1912), 1 [[male]]; - Landjoro, dans le Pori (900 m., st. n° 64. mars 1912), 2 [[male]].
Ces [[male]], captures sans les [[worker]], sont indeterminables specifique- ment, dans l'etat actuel de nos connaissances. Il en est de meme pour beaucoup d'especes, c'est pourquoi il faut autant que possible capturer les Formicides dans leur nid, ou l'on a la chance de trouver tous les sexues reunis.
Platythyrea is a genus of predaceous ants in the subfamily Ponerinae and the sole member of the tribe Platythyreini.[2]
The genus has a worldwide distribution, and is found in the tropics and subtropics of the world.[3]
Workers are small to very large in size (4–20 mm). Gamergates (reproductive female workers) are known from all studied species except one, P. conradti, which have ergatoid queens (wingless reproductive ants, intermediate in form between workers and winged queens). Some species with gamergates also have alate queens, which are similar to the workers but winged.[3]
Parthenogenesis is a natural form of reproduction in which growth and development of embryos occur without fertilisation. Thelytoky is a particular form of parthenogenesis in which the development of a female individual occurs from an unfertilized egg. Automixis is a form of thelytoky, but there are different kinds of automixis. The kind of automixis relevant here is one in which two haploid products from the same meiosis combine to form a diploid zygote (see diagram).
Colonies of Platythyrea punctata from Florida and the Caribbean Islands produce offspring almost exclusively by automictic thelytoky.[4] Automixis appears to involve central fusion of two of the haploid products of meiosis (see diagram). This form of automixis tends to maintain heterozygosity in transmission of the genome from mother to offspring, and to minimize inbreeding depression. Furthermore, crossover recombination occurs at a greatly reduced rate during meiosis,[4] which likely restrains the transition from heterozygosity to homozygosity.
Platythyrea is a genus of predaceous ants in the subfamily Ponerinae and the sole member of the tribe Platythyreini.
