|The Ants of
SUBFAMILY FORMICINAE - Genus Lepisiota
|Contents - Formicinae - FORMICINAE Introduction|
In Tribe PLAGIOLEPIDINI.
Diagnostic Features - Antennae 11-segmented. Eyes well developed, ocelli present but may be reduced. Mandibles with the apical margin oblique and dentate, overhung by clypeus. Alitrunk constricted in the mesonotal region, the propodeum swollen and bidentate or bituberculate. Petiole a scale with the dorsal margin bispinose, bidentate or emarginate. Acidopore borne on a conical projection of the hypopygium, surrounded by a fringe of hairs.
On the generic nomenclature, Bolton (1994: 51) gave Acantholepis
as reduced to the status of a homonym of Lepisiota
but cited no authority. Acantholepis was used by all early
authors and even as late as Belshaw & Bolton
(1994b). H÷lldobler & Wilson (1990) gave the authorities as being Acantholepis
Mayr 1861: 42 and Lepisiota
Santschi 1926a: 15 (as a subgenus of Acantholepis). The name Lepisiota
had been applied to Acantholepis
species in Baroni
Urbani, Bolton & Ward (1992: 303) but without any explanation.
Bolton (1995: 33) revealed the older name was applied to a fish genus
from Denmark by Kroyer in 1846. Thus he raised, Lepisiota,
formerly a subgenus of Acantholepis, to genus status for the
ants. The need for a replacement name had been recognised by
Pagliano & Scaramozzino (1990: 4), but Bolton (1995: 22) had their Baroniurbania as an unnecessary
replacement name, preceded by the earlier Lepisiota.
It seems that the prior formal synonymy of Baroniurbania under Lepisiota was by Xu. 1994. A
taxonomic study of the ant genus Lepisiota
Southwestern China (Hymenoptera Formicidae Formicinae) Journal of Southwest Forestry College,
14(4): 232-237; in
Chinese but that was published too late for inclusion in Bolton (1995).
Reference: Pagliano, G. & Scaramozzino, P. 1990. Elenco dei generi di Hymenoptera del mundo. Memorie della Societa Entomologica Italiana, 68, 1-210]
nov. per Acantholepis Mayr, 1861 (44
Formicinae) preocc. da Kroeyer, 1846.
There is an anomaly here as Mayr (1861) defined his new genus Acantholepis with a single species, A. frauenfeldi, the species he first described as Hypoclinea Frauenfeldi (Mayr, 1855: 378). In his key to genera (Mayr 1861: 26) he separated Acantholepis n. g. and Plagiolepis n. g. by the former having ocelli and the latter not; also by the Acantholepis having a small, slender alitrunk, the propodeum with small spines; whereas, Plagiolepis had the pronotum and propodeum wider than the mesonotum, and the propodeum unarmed. A. frauenfeldi was listed as the type species by Emery (1925b: 23). Wheeler (1911f: 165) listed Hypoclinea as a subgenus of Dolichoderus, and gave as type species Formica quadripunctata Linnaeus, 1771 (second species by designation [i.e. in the Mayr, 1855, list]), presumably as it was described first. The latter, however, now is regarded as Dolichoderus quadripunctatus (Linnaeus).
Bolton (1995) in elevating Lepisiota to the genus name gave the type species as Lepisiota rothneyi. That was described as Plagiolepis rothneyi by Forel (1894c: 415) but was placed in Acantholepis (Lepisiota) by Santschi (1926a: 15). The latter clarified and restated the definition of the genera Plagiolepis and Acantholepis; adding definitions of the subgenera Acantholepis and Lepisiota. These are at . Under his definition of Plagiolepis at , Santschi (1926a) remarked "The species of Asia I have previously considered as in this subgenus [Anacantholepis] must pass to the following genus [Acantholepis] as a new section [i.e. Lepisiota].
Other than L. rothneyi, the sole Acantholepis species reported or described by Santschi from Asia was Plagiolepis (Anacantholepis) Demangei (Santschi, 1920a); a third species Plagiolepis moelleri Bingham (1903) was listed under Asian Plagiolepis (Anacantholepis) by Emery (1925b: 23).
As a genus type L.
rothneyi is anomalous; with a low rounded petiole and the
propodeum profile smoothly rounded without sign of spines or even
angular protuberances. With the exception of its two Asian relatives,
all other species presently included in Lepisiota
have a raised petiole scale and at least a pronounced angle between the
propodeum dorsum and declivity; commonly teeth or spines are present
on the propodeum, the petiole, or both. Ocelli are inconsistent
in their development, ranging from easily seen to apparently absent. As
with its two relatives, rothneyi has
short antennal scapes that surpass the occiput by no more than
one-sixth their length. With few exceptions, e.g. L. mota from Angola, that
otherwise have the "Acantholepis"
characters, the other species have scapes that surpass the occiput but
at least one-quarter of their length.
Emery (1925b: 23) had it in Plagiolepis. Forel's (1894c) description is at . Bingham (1903: 320) had it in his key to Indian Plagiolepis and a description; these are . The confused status of the "Plagiolepis" species is shown by the first couplet of the key separating off the now Anoplolepis gracilipes (listed as Plagiolepis longipes); Plagiolepis moelleri remains in that genus but Plagiolepis wroughtoni (originally described as Plagiolepis Rothney race Wroughtoni new stirps, Forel, 1902d: 293) now is under Lepisiota.
It seems possible, perhaps highly likely, that a modern review of the type specimens of Lepisiota rothneyi, the subspecies listed by Bolton (1995: 228) and its two relatives, would lead to their being reverted to quite ordinary Plagiolepis, or a separate genus Lepisiota, with three member species, rothneyi, demangei and moelleri. In the latter context the only obvious difference is the presence of poorly developed ocelli. If L. rothneyi is placed in Plagiolepis or Lepisiota the latter is invalid as the replacement genus name for Acantholepis.
From the original descriptions, illustrations and specimens that I have drawn or illustrated, I have attempted to draw up keys to the species. These are not intended to be truly authorative but at least a guide to the apparent main groups. It is apparent that a modern review of the type specimens and fresh material would lead to synonymization and, especially, in the case of "capensis", separation into several more species. Having decided (2004) to expand the coverage to all species from sub-Saharan Africa, it has become clear that the dimorphism I found in the specimens I tentatively identify as Lepisiota cacozela is not unique, or an aberrant occurrence, as Weber (1943c) described L. megacephala from a single apparent soldier. I have been unable to find any reference to dimorphism from outside Africa, although there is a range of sizes in L. rothneyi from India.
An early key which included Acantholepis species from Africa was compiled by Forel (1892a). This is at and (Indian species) . Forel referred to capensis as having whitish erect pilosity on the body but not on the tibiae or scapes. The colour of the pilosity in the type capensis, i.e. from South Africa, however, is clearly blackish.
Notes on sub-Saharan Africa species
Strickland (1951a) described Acantholepis as small black ants, more likely to be found on seedling cocoa than on mature trees and essentially soil nesting. He regarded them as of little economic importance as far as cocoa was concerned.
Bernard (1952) described genus members (as Acantholepis) as more common than their relatives Plagiolepis and Anoplolepis in the Guinea, Mt. Nimba surveys; adding that the nests often are very resistant to inundation, which leads to their being abundant among the ants known from close to the River Niger (according to Monod). Under one of the species, he added that the Acantholepis are individually very variable, and refrained from describing new species as it would be better to await more examples. Bernard also referred to species in the subgenus Pseudacantholepis Santschi, being very small and poorly collected forms; and, other than A. laevis [see below as a subspecies of capensis], previously unknown from French West Africa. Bolton (1995) noting that he found no record of type species for the subgenus and (apparently) no Santschi reference, regarded the subgenus name as "unavailable".
Lepisiota capensis (Mayr) - listing as in Bolton
(1995: 227) with links to species as I have separated them
ę 2007, 2008, 2009, 2010, 2011, 2013 - Brian
Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.