Melissotarsus weissi

AntWiki: The Ants --- Online
Melissotarsus weissi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Melissotarsus
Species: M. weissi
Binomial name
Melissotarsus weissi
Santschi, 1910

Melissotarsus weissi casent0178294 profile 1.jpg

Melissotarsus weissi casent0178294 dorsal 1.jpg

Specimen labels

Synonyms

These ants live in galleries under the bark of trees (as do all known members of this genus). They do not forage on the surface of trees, but tend small coccids within their galleries. Nests are large with many hundreds of workers and are probably polygynous (with multiple queens) (Delage-Darchen, 1972).

Identification

Lighter coloured workers may sometimes be difficult to separate from Melissotarsus emeryi, but in general the sharper marginations of the sides of the mesosoma in weissi are fairly distinct. The sexual forms of weissi are both easily separated from those of emeryi as the male of the former is dark brown to black (pale yellow and feebly sclerotized in the latter), and the female of weissi has the postpetiole relatively narrow in dorsal view with an arched-convex anterior margin, as opposed to a very broad and distinctly transverse postpetiole in emeryi. (Bolton 1982)

Keys including this Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 7.733333° to -0.317°.

 
North
Temperate
North
Subtropical
Tropical South
Subtropical
South
Temperate

Distribution based on Regional Taxon Lists

Afrotropical Region: Central African Republic, Congo (type locality), Democratic Republic of Congo, Ghana, Ivory Coast, Kenya.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.
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Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.
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Biology

Garcia, Wiesel and Fischer (2013) - The four species of this Afrotropical and Malagasy genus are rarely encountered. The Afrotropical species were revised by Bolton (1982) who also provided a good species identification key. These ants are special in several ways. They build their nests in healthy wood by tunnelling through the living tissue beneath the surface (Bolton, 1982; Fisher & Robertson, 1999; Belshaw & Bolton, 1994) and are rarely found outside of their nests, which could be the main reason for their relative scarcity in museum collections (Bolton, 1982). They live in close association with symbiotic coccids that are kept inside the nest. Adults are able to produce silk, which is used to close exit holes or to seal cracks (Fisher & Robertson, 1999).

Bolton (1982) - This small genus, of which only four uncommon species are presently recognized, is restricted to the Malagasy region (1 species) where it is rare, and the Afrotropical region (3 species) where it is, however, very widespread. The species nest in the healthy wood of living trees, apparently tunnelling their own galleries below the surface. For this reason most collections of Melissotarsus are made more by luck than by intent as their presence in the wood is usually not detectable on the surface. Delage-Darchen (1972) has shown that the method of walking in these ants is very strange; they progress on their front and hind legs with the middle pair projecting upwards, and presumably in contact with the gallery roof. She also noted the presence of coccids inside the galleries, also discussed by Ben-Dov (1978). It seems probable that coccid secretions form a major, if not the main, item in the diet of Melissotarsus species.

Castes

Images from AntWeb

Melissotarsus weissi casent0401869 head 1.jpgMelissotarsus weissi casent0401869 profile 1.jpgMelissotarsus weissi casent0401869 dorsal 1.jpgMelissotarsus weissi casent0401869 label 1.jpg
Worker. Specimen code casent0401869. Photographer April Nobile, uploaded by California Academy of Sciences. Owned by CAS, San Francisco, CA, USA.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • weissi. Melissotarsus weissi Santschi, 1910c: 356, fig. 3 (q.) CONGO.
    • Type-material: holotype queen.
    • [Note: Bolton, 1982: 337, comments that only the gaster and one forewing of the holotype remain on the mount.]
    • Type-locality: Congo (“Congo français”): Brazzaville, ii.1907 (A. Weiss).
    • Type-depository: NHMB.
    • Bolton, 1982: 335 (m.).
    • Status as species: Emery, 1922e: 119; Wheeler, W.M. 1922a: 823; Bolton, 1982: 337 (redescription); Bolton, 1995b: 250; Hita Garcia, et al. 2013: 212.
    • Senior synonym of major: Bolton, 1982: 337; Bolton, 1995b: 250.
    • Senior synonym of titubans: Bolton, 1995b: 250.
    • Distribution: Congo, Democratic Republic of Congo, Ghana, Ivory Coast.
  • major. Melissotarsus major Santschi, 1919h: 85 (w.) DEMOCRATIC REPUBLIC OF CONGO.
    • Type-material: syntype workers (number not stated).
    • Type-locality: Democratic Republic of Congo (“Congo belge”): Penghe, 13.ii., no. 125 (Bequaert).
    • Type-depositories: MRAC, NHMB.
    • Santschi, 1923e: 277 (q.m.).
    • Status as species: Wheeler, W.M. 1922a: 823; Santschi, 1923e: 277.
    • Junior synonym of weissi: Bolton, 1982: 337; Bolton, 1995b: 250.
  • titubans. Melissotarsus titubans Delage-Darchen, 1972a: 216, figs. 1-10 (w.q.m.l.) IVORY COAST.
    • Type-material: syntype workers, syntype queens, syntype males (numbers not stated).
    • Type-locality: Ivory Coast: Lamto, 200 km. NE Abidjan (Delage-Darchen).
    • Type-depository: unknown (not stated, perhaps in Delage-Darchen personal collection).
    • [Note: in xi.1983 Mme Delage-Darchen sent a series identified as M. titubans (workers and a queen) to BMNH. It is not known if this was part of the type-series, nor is it certain that an official type-series exists.]
    • Wheeler, G.C. & Wheeler, J. 1980: 531 (l.).
    • Junior synonym of beccarii: Bolton, 1982: 336.
    • Junior synonym of weissi: Bolton, 1995b: 250.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Bolton (1982) - So little material of Melissotarsus is available at present that this survey must be regarded as strictly preliminary. Three species are now recognized in the Afrotropical region but it is possible that each may be compounded of more than one different sibling-species. Conversely it is by no means impossible that further collections will bridge what appear here as species for the differences between them, though consistent in the few samples to hand, are relatively minor and may well be anulled by further collecting.

The three presently recognised species are basically so similar that to present a full description for each would be redundant so, for the purposes of identification, a description of the type-species beccarii is given and the other two are compared to it.

The shape of the mesosoma in dorsal view shows subtle but perhaps significant differences between separate series of workers presently grouped as single species, but discovering whether these differences are meaningful, or even consistent, will have to await the amassing of considerably more samples than are presently available.

For the present I define weissi as having a dark brown to black strongly sclerotized male, and a similarly coloured female in which the postpetiole in dorsal view is quite narrow (1.20-1.40 x broader than long) and has a rounded or even hemispherical anterior margin. The worker of weissi has the mesosoma medium to dark reddish brown, the anterior margin of the pronotum in dorsal view sharply defined and angular where it meets the anterior declivity, and the sides of the mesosoma meeting the dorsum in a fairly well-defined angle.

Description

Worker

Bolton (1982) - TL 2.3-3.0, HL 0.58-0.74, HW 0.60-0.78, CI 98-104, SL 0.27-0.34, SI 41-47, PW 0.36-0.50, AL 0.56-0.84 (14 measured).

Answering to the description of Melissotarsus beccarii but darker in colour, the mesosoma medium to dark reddish brown; with the anterior pronotal margin meeting the anterior declivity in a well-defined angle or edge, and with the sides of the mesosoma meeting the dorsum in a fairly well-marked angle.

References

References based on Global Ant Biodiversity Informatics

  • Bolton B. 1982. Afrotropical species of the myrmicine ant genera Cardiocondyla, Leptothorax, Melissotarsus, Messor and Cataulacus (Formicidae). Bulletin of the British Museum (Natural History). Entomology 45: 307-370.
  • Garcia F.H., Wiesel E. and Fischer G. 2013.The Ants of Kenya (Hymenoptera: Formicidae)—Faunal Overview, First Species Checklist, Bibliography, Accounts for All Genera, and Discussion on Taxonomy and Zoogeography. Journal of East African Natural History, 101(2): 127-222
  • Hita Garcia, F., G. Fischer, M.K. Peters, R.R. Snelling and H.W. Wagele. 2009. A preliminary checklist of the ants (Hymenoptera: Formicidae) of Kakamega Forest (Kenya). Journal of East African Natural HIstory 98(2): 147-165.
  • Santschi F. 1910. Formicides nouveaux ou peu connus du Congo français. Annales de la Société Entomologique de France 78: 349-400.
  • Santschi F. 1923. Descriptions de nouveaux Formicides éthiopiens et notes diverses. I. Revue Zoologique Africaine (Brussels) 11: 259-295.
  • Weber N. A. 1952. Studies on African Myrmicinae, I (Hymenoptera, Formicidae). American Museum Novitates 1548: 1-32.
  • Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004