Genus Pseudolasius Emery (1887a: 244)

In Tribe LASIINI, previously PRENOLEPIDINI.

Diagnostic Features - Polymorphic. Antennae 12-segmented; with their insertions virtually confluent with the posterior clypeal margin. Mandibles with five-six teeth, some with 7-8 teeth, set upon an oblique border. Palpi short. Major workers with small eyes, on the dorsum of the head, at or near the midlength. Minors without eyes. Petiole a scale which may be inclined forwards. Dorsal surfaces without distinct paired hairs.

Bolton (1973a) describes them as small depigmented to yellowish ants, nesting in or under very rotten wood, or in the soil at the base of trees. Normally avoid light but can be found on the soil surface at night. Bernard (1952) stated that 6 species were known from Africa and thought that they might well be common in the subsoil; adding that they raise Homoptera on roots in the same way as Lasius ants in Europe.

Emery's (1887a) genus definition is at .

Emery gave four species, the former Lasius familiaris Sm. and the former Prenolepis sumatrensis Mayr; plus descriptions of Pseudolasius pheidolinus, from Java, and Pseudolasius breviceps, from Amboina.  All were eyeless.

Forel (1913k) on South Asian species gave a number of new descriptions and comments; this at . Wheeler's (1922) descriptions of the Congo Basin species is at . Menozzi's (1924b) key is on .

Note - the following paper appeared to alter the situation
LaPolla, John S. (2004) Taxonomic review of the ant genus Pseudolasius (Formicidae: Formicinae) in the Afrotropical region. Journal of the New York Entomological Society, 112, (2-3) 2004. 97-105.
The ant genus Pseudolasius in the Afrotropical region is reviewed. Two species are considered valid, P. bufonus and P. weissi, and diagnostic morphological characters are provided for each. Scanning electron micrographs are provided for each species, and the male genitalia of P. bufonus are illustrated for the first time. Four species are synomized with P. weissi: P. bayonii new synonym, P. bucculentus new synonym, P. gowdeyi new synonym, and P. weissi sordidus new synonym.
Dept Entomol, Smithsonian Inst, MRC 188, POB 37012, Washington, DC, 20013, USA.

LaPolla, Brady & Shattuck (2010: 123) considered that the African Pseudolasius were anomalous and should be separated from the essentially South Asian genus.

On what seem to be very tenuous grounds they placed the African species, weissi and bufonus, in their new genus Paraparatrechina.

They commented "One difference between the two is that Ps. bufonus has several erect setae on the mesosoma [alitrunk]", a characteristic that differs from the 2.1.1 pattern of most Paraparatechina. This suggests weissi does not have such hairs, which is wrong, although the erect hairs are smaller and semi-decumbent.

It has to be said that their SEM images show Pseudolasius that are almost indistinguishable from the two African species. The Pseudolasius they show, by deduction P. australis, has small but much larger eyes than the original members of Emery's eyeless genus.

The two African species have highly reduced or no eyes, whereas all known Paraparatrechina have well developed eyes. Whilst the data provided to accompany their paper shows they studied P. weissi but that was the sole African species, other than the tramp P. longicornis.

Their reference to P. weissi as BLF2139 does not gel with the Antweb list where the sole specimens imaged are a queen and a male from Gabon, with unimaged workers from Kenya (accessed 7.iii.2011; unchanged 18.iii.2012).  Antweb, however, shows a major worker, BLF4000 (CASENT0406725), from the Central African Republic, as "Pseudolasius undet.".  Whilst the queen was described by Santschi (1910c) the male has never been reported.  Santschi gave the queen as TL 6.5-7 m, whereas the Antweb queen has TL ca 8.5 mm.

In a further paper from the Prenolepis-group study, LaPolla, Kalla & Brady (2012) provided a revised key to the genera.  The opening couplets have:

1. Maxillary palps with five or fewer segments; species often strongly polymorphic, with as major and minor caste expressed  ..... 2

2. Polymorphic Afrotropical species  .......  Paraparatechina (weissi species-group).

The specimen they included in their list of species from genomic DNA analysis as studied is given as USNM00756224.  The list included no other species endemic to Africa.  The Zatania male shown in their paper is quite different from  P. weissi male shown on Antweb (see above), with a different shaped head and genitalia, with dense pilosity.

Note - References:
LaPolla, J. S. (2004) Taxonomic review of the ant genus Pseudolasius (Formicidae: Formicinae) in the Afrotropical region. Journal of the New York Entomological Society, 112, (2-3) 2004. 97-105.
The ant genus Pseudolasius in the Afrotropical region is reviewed. Two species are considered valid, P. bufonus and P. weissi, and diagnostic morphological characters are provided for each. Scanning electron micrographs are provided for each species, and the male genitalia of P. bufonus are illustrated for the first time. Four species are synomized with P. weissi: P. bayonii new synonym, P. bucculentus new synonym, P. gowdeyi new synonym, and P. weissi sordidus new synonym.

LaPolla, J. S., Kalla, R.J. & Brady, S.G. (2012) A new ant genus from the Greater Antilles and Central America, Zatania (Hymenoptera: Formicidae), exemplifies the utility of male and molecular character systems. Systematic Entomology, 37, 200-214.

With a range of fresh specimens from Cameroun and the availability of type images from the MCZ and Antweb, now (2011), I have reviewed the situation and agree with LaPolla's synonymy into two distinct species. However. it is clear gowdeyi is a junior synonym of bufonus and not of weissi. It appears also that the bufonus and gowdeyi types were media and minor workers. Note: the majors of bufonus I have from Cameroun do not have erect hairs on the legs or scapes; as stated by Wheeler, 1922: 1922: 223, for gowdeyi

Key to workers

Major head cordate; major with distinct eyes (or markings in the eye position) with very short suberect setae on the alitrunk, TL major ca 3 mm, minor ca 2.5 mm junior synonyms bucculentus, bayonii and myersi	weissi
Major head with occiput only shallowly impressed and with sides subparallel; with numerous quite long erect setae on the alitrunk dorsum; alitrunk slender, only shallowly concave between mesonotum and propodeum; petiole scale low more or less overhung by the gaster; TL major 2.8-3.0 mm (Cameroun majors TL ca 4.0 mm), minor 2.5-3.0 mm junior synonym gowdeyi	bufonus

Unassignable forms

Pseudolasius species (indet.) Bernard form

Bernard (1952) noted from Mt. Nimba, Guinea, a single small eyeless worker (labelled Nimba, Lamotte), with a squarer head and more claviform antenna than the known species, but declined to define a new species on the basis of a sole minor worker.

Pseudolasius species (indet.)

Many workers were found in Ghana, in leaf litter (270) and soil samples (4) under primary forest at Bobiri, a logged area at Atewa Forest Reserve, primary and secondary forest at Bunso, and under cocoa at Ofinso, by Belshaw & Bolton (1994).