First Discovery of the Queen ant of

Leptanilla macauensis

E.Ng et S.H., 10 Oct., 2018


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 ●  The living queen ant of Leptanilla macauensis

Foreword: The subfamily Leptanillinae is belongs to formicidae and represents of the primitive branches from the evolution of ants. Although they have the quite different size for their body lengths, Leptanilla has been closely linked with the subfamily Ponerinae. Nearly 40 species of Leptanilla are found in the world (Afrcotropical, Australasia, Indomalaya and Palaearctic region), all of them are subterranean ants, whereabouts are strictly mysterious, they are generally not easy to come on the ground, so that many new species of discovery is based on a small number of worker specimens, even if the properties of the species has been established, the location of the ant's nests can not be traced, and other gender castes of the colony is ignorant. In recent years, two species of Leptanilla were  found in Southeast Asia, Leptanilla hypodracos Guénard et al., 2016 from Singapore, which was based on two worker specimens, and one of them is incomplete; Leptanilla macauensis Guénard et al., 2018 from Macau was based on 5 worker specimens, these two new species have been determined and named after Dr. Guénard's (The University of Hong Kong) identification.

Acta Scientrium Ngensis was founded on Macau, Macaology studying  is our righteousness. We volunteered for this hard and unprofitable investigation, and never have the wishful thinking. Index Pteridoflora hongkongense et macaoense was included in the updated checklist species of ferns of Hong Kong & Macau (2007), after our investigation project of pteridology of Macau. In 2011, the Geological Survey for the entire territory of Macau (geographical boundaries of the Portuguese Era) was carried out, we summarized our researching and published our special topic in geology of Macao, Aetas Geologica Macaoense.

Until recently, we heard that a new ant species is found in Colina de Ilha Verde, Macau, and decided to investigate this area and wish to have some new finding, we believe that this is undoubtedly beneficial, so we decided to do some our own small, hope can help to the scientific description of the Leptanilla macauensis can be more perfect, and this is also the authors wish!

Key words:  Leptanilla macauensis Guénard et al., 2018,  queen caste,  Leptanilla hypodracos Guénard et al., 2016,  Colina de Ilha Verde, Macau,  Dr. Benoit Guénard.

The Importance of the discovery: Leptanilla is one the most primitive groups in the formicidae, distributes widely in tropical and subtropical regions. It is generally believed to originate from the Late Jurassic period to the Early Cretaceous, equivalent of the era of Archaeopteryx in the Paleozoic world, which proved that the natural history of the formicidae was pushed forward nearly 40 million years, it's say these primitive insect that are still with us today! It is absolutely valuable to assess the natural history of Macau as such a primitive species in a tiny city with highly urbanization. No exact identified specimen of Leptanilla so far in  Hong Kong is found.

Methodology of collecting: Leptanilla is subterranean ants and rarely found due to their cryptic habitat, it seem to be specialized predators of geophilomorph centipedes (Masuko, 1990). They may be found in litter soil near ground level, In general, there are three collecting methods: (1) Wrinkle extractor - Soil samples are collected from habitat area, placing in the inner net bag then covered with outer bag which the collecting bottle with water is attached to the hole, hanging up for 7 ~ 15 days, waiting the tiny creatures drops from the soil bag into collecting bottle. (2) Subterranean traps, this method seems to be not suitable for Macau, (3) Hand Collecting, directly but depends on probability, although it's not the best way, the queen caste is collected by this way.

 ●   Leptanilla macauensis Queen ant was clinbing the slip surface

Habit of the Queen ant: The Queen ant is a female in the nest with fertility, (male and female mating and parthenogenesis form), is a member of the responsibility to reproduce offspring, also can be called the Empress of an ant colony, the status is very obvious. Nevertheless, sovereignty acceptance of new queens (queen selection) is depends on the will of the worker, we still have not well understanding of queen caste, we only know that the queens of some species are known to feed on their larvae which have special organs that exude the haemolymph[4].



Class: Insecta

  Subclass: Pterygota

      ● Superorder: Endopterygota

          ● Order: Hymenoptera

               ● Family: Formicidae

                   ● Subfamily: Leptanillinae

                        ● Tribe: Leptanillini

                           ● Leptanilla macauensis Guénard et al., 2018

Line drawing of Worker (Upper left: refer to the incomplete specimen) and (Upper right) Queen ant
● Gynetype specimen of Queen ant of Leptanilla macauensis

Worker (left): Refer to the incomplete specimen (Topotype specimen collected by us), estimated measurement of body length is about 1.2mm, more detailed descriptions of the workers are needed to be further specimen collected and updated. (This paper is focuses on queen ant only).

Depository: The University of Hong Kong (Holotype)


Queen (right): Specimen ID: NGIN-731154, Gynetyprus / Gynetype, New queen, Location: Colina de Ilha Verde, Macau, ca.22°12'43"N, ca.113°32'17"E, Climate condition: 27°C, Sunny / Clear, Date of collected: 06 X 2018, Preservation State: Natural death in the feeding ant tube, persevered by 80% ethanol-glycerol buffered mixture solution, Method of Collecting: Hand selection.

Depository: Acta Scientrium Ngensis (Gynetype)

Overall diagrams:

Diagrammatic description of Leptanilla macauensis Guénard et al., 2018, Queen caste

Ac: Antennal club, Ap: Acidopore, Cly: Clypeus,Co: Coxa, Es: Eyespot, Fe: Femur, Fl: Flagellum, Ga: Gaster, Ma: Mandible, Oc: Occiput, Pet: Petiole, Pro: Pronotum, Prop: Propodeum, Py: Pygidium, Sc: Scape, Scut: Scutellum, Se: Stemite, T: Tibia, Tc: Tarsal claw, Te: Tergite, Ts: Tarsus

I. Dorsal view; II. Side view;  III. Ventral view

Description of various parts of Leptanilla macauensis Guénard et al., 2018, Queen caste


Measurings: (Values or "l=" are indicate in length, TL: Total length "w=" width, "h=" hight, "d=" diameter)

I. Head

Antennae: Sc:0.15mm, Fl: 0.36mm, Ac:0.15mm,  Head:(l=0.51mm, w=0.28mm, h=0.21mm),  Ma: (l=0.18mm,w=0.05mm); Es: d=0.02(0.017)mm, Neck(w=0.09mm)

II. Mesosoma & Petiole

Frontal leg: Co: 0.13mm, Fe:0.18mm, Ts: 0.22mm, Ts: ca.0.08mm, Mesosoma: TL=0.78mm: Pro: (L=0.22mm, h=0.25mm), Scut: (l=0.25mm, h=0.24mm) Prop: (l=0.20mm; h=0.19mm), Pet: (l=0.07mm, w= ca. 0.04mm)

III. Gaster

 TL=1.1mm, h (max.)=0.40mm, Se IV: h=0.38, Se V: (h=0.35mm), Se VI: (h=0.31mm),  Se VII:( h=0.25mm) Ap: (w=0.06mm)


Total Length: 2.1mm, antennal club to scape: 0.6mm, 12 flagella segments, Length of head: 0.4mm, wide: 0.2mm, mesosoma (D): 0.6mm, gaster (G): 1.1mm, redish brown color (living specimen), the naked eye is clearly recognize, with eyespots (Es) (worker: eyesless), queen ant is 2 times larger than the worker, and the shape of the clypeus (Cly) is wider and the abdomen from the bottom of the mesosoma is very different from the worker, especially in the lower part, The worker has two petioles, but the queen has only one section (no postpetiole), gaster enlargement, only for the length of a fairly long worker ant, the speed of movement in the soil is slow, was found alone in the underground about 10 cm under the soil.

Queen, other species:


 ● Upper left: Left: new queen of Leptanilla revelierii. Emery, 1870 [3]
● Upper right: Queen ant of Leptanilla japonica Baroni Urbani, 1977 feed on hemolymph from her larval [4]


[1] Leong CM, S Yamane, & B Guénard. Lost in the city: discovery of the rare ant genus Leptanilla (Hymenoptera: Formicidae) in Macau with description of Leptanilla macauensis sp. nov., Asian Myrmecology 10: e010001. PDF.

[2] Wong M, & B Guénard. Leptanilla hypodracos, a new species of the cryptic ant genus Leptanilla (Hymenoptera: Formicidae) from Singapore, with new distribution data and an updated key to Oriental Leptanilla species. Zookeys 551: 129–144. PDF

[3] López, F.; Martínez, M. D.; Barandica, J. M. 1994. Four new species of the genus Leptanilla (Hymenoptera: Formicidae) from Spain - relationships to other species and ecological issues. Sociobiology 24: 179-212 PDF

[4] K. Masuko, Larval Hemolymph Feeding in the Ant Leptanilla japonica by Use of a Specialized Duct Organ, the "Larval Hemolymph Tap" (Hymenoptera: Formicidae), Behavioral Ecology and Sociobiology, Vol. 24, No. 2 (1989), pp. 127-132


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