Ants of Africa
SUBFAMILY FORMICINAE - Genus Paratrechina and related species
|Contents - Formicinae - FORMICINAE Introduction|
In Tribe LASIINI (Ashmead, Emery emend, 1925b: 212, previously PRENOLEPIDINI.
Diagnostic Features - Dorsal surface of head, alitrunk and gaster with distinctly paired coarse hairs. Eyes well developed and set at or in front of the mid-length of the head. No ocelli. Antennae 12-segmented and inserted close to the posterior margin of the clypeus. Anterior clypeal margin entire or weakly emarginate medially. Mandibles narrow, with five or six teeth. Palpi long. Propodeum unarmed. Petiole a reduced scale inclined forwards and often overhung by the first gastral segment, always unarmed above. Acidopore borne on a conical projection of the hypopigium, and surrounded by a fringe of hairs.
Separation of African genera - following consideration of LaPolla, Brady & Shattuck (2010a) and LaPolla, Hawkes & Fisher) 2011) and the following assessment, I have compiled a fresh Paratrechina key 2012.
Africa most species were regarded as in the
subgenus Nylanderia Emery (as a
subgenus of Prenolepis, Emery, 1906b: 133; then as
a subgenus of Paratrechina,
Emery, 1925b: 217). Emery (1925b) transferred a number of species from Prenolepis
to Paratrechina, including all those known from
Africa. The definition of Nylanderia (Emery, 1906b:
was that the alitrunk is not significantly narrowed in the mesothorax
region nor swollen to the anterior or posterior of that region; also
scapes and tibiae covered with short pubescence and in many cases with
sparse erect or semierect simple hairs. That separation, however, was
as a subgenus from a group of species in the genus Prenolepis.
La Polla, Brady & Shattuck (2010a) wrote a quite dramatic revision, with good evidence from molecular phylogeny.
LaPolla, J.S., Brady, S.G., & Shattuck, S.O. 2010a. Phylogeny and taxonomy of the Prenolepis genus-group of ants (Hymenoptera: Formicidae). Systematic Entomology, 35, 118-131.
In their Taxonomic History, they state - "Motschoulsky (1863) described Paratrechina based on Pa. currens (which is now a synonym of Pa. longicornis Latreille, 1802) but the genus received little attention and was synonymized with Prenolepis by von Dalla Torre (1893). Emery (1925) removed Paratrechina from synonymy with Prenolepis as part of his world species catalogue, and it was at this time that many species were transferred to Paratrechina from Prenolepis". From that, as "Paratrechina longicornis" represents a distinct lineage and is the type species, Paratrechina is redefined as a monotypic genus.
This assessment, however, can be argued as fundamentally flawed.
Motschoulsky defined the new Genus as (my translation) : Very close to Tapinoma, but the clypeus with an arced anterior margin without any incision, antennae more linear (narrow?), with the first segment of the funiculus longer than the second, alitrunk (mesosoma) terminated posteriorly by two more or less raised tubercles, gaster triangularly acuminate behind and covered with long hairs that are sparse as on the rest of the body. Head without ocelli.
The type species described and illustrated (right), but not designated as such, by Motschoulsky was Paratrichina vagabunda (the genus name being differently spelt), from the Montagnes de Patannas (Sri Lanka).
My translation from the Latin, of his species description is : TL 2.54 mm, HW 0.53 mm, subelongate, dark erect hairs, piceous, legs femora and tarsi testaceous white; eyes black, oblong and flat, placed on top of the head; head oblong, raised between the antennae, clypeus convex, semilunate, without a carina; antennae relatively short, first segment of the funiculus longer than the second; alitrunk subelongate, medially constricted, posteriorly gibbous (dome-shaped), apex bituberculate; petiole scale oblong; gaster ovate anterior rounded apex acuminate; tarsi moderate; body overall with sparse long hairs.
This clearly is not Formica/Prenolepis/Paratrechina longicornis. From the illustration, the antennae and legs are far too short relative to the body and the alitrunk is too short and thick (Motschoulsky used the term subelongate). From the genus and species descriptions, the propodeum in P. longicornis is long and low not gibbous. Also in longicornis the propodeum is not bi-tuberculate (i.e. it lacks raised spiracles). The eyes are convex and lateral in longicornis.
Below the vagabunda description, Motschoulsky wrote of: A second smaller species, more slender and of a lighter colour on the alitrunk and legs is not rare (uncommon) on the plants in our hot houses [he lived in St Petersburg] and I have named this Paratr. currens.
native French speaker, Dr Philippe Annoyer, feels that Motschoulsky
used "je l'ai nommée" because he had observed the second species many
times before and had thought of the name currens
well before writing the paper. Philippe suggests the name currens
spring from the species running quickly = "currens traduction".
Arguably, Motschoulsky, whose paper was on the ants of Ceylon (Sri
Lanka), included the species as an aside because it fitted his new
The main problem with placing any reliance on Dalla Torre was that he produced a catalogue with no indication of any analysis or even examination of the species he listed. From some of the references, it seems Emery played a part in the synonymization.
This was confirmed by Emery (1892b: 8), who stated he had no doubt the Motschoulsky genus was identical to Prenolepis Mayr and the species Pr. vagabunda was a form close to Pr. vividula Nylander.
I show (right) a specimen of P. vividula from Egypt. as can be seen, apart from the paler colour, the overall form and dimensions is similar to Pr. vagabunda.
P. vagabunda seems never to have been recorded since Motschoulsky. Forel (1894c: 406 ff) describing ants from India cited P. currens as a junior synonym of P. longicornis, presumably following Emery's synonymy, but made no reference to P. vagabunda and neither did Bingham (1903). I surmise that neither had read Motschoulsky's paper.
Forel (1894c) did key out two dark brown to black species, Prenolepis bourbonica (Forel) r. bengalensis, n. st. , and Prenolepis yerburyi n. sp.. He separated the two species principally from the male genitalia, commenting the workers were very similar, both had wholly brown to dark brown legs and antennae. The bengalensis he gave as having a more oval and elongated head than the type form and with the anterior margin of the clypeus less deeply impressed (see bourbonica). LaPolla et al (2010a) list bourbonica, without giving bengalensis, and yerburyi under Nylanderia, presumably following Emery (1925b: 220)..
Bingham (1903), however, gave P. yerburyi as light brown. Another generally black species is Prenolepis birmana Forel, 1902d: 201(now in LaPolla et al's list of Nylanderia). That Forel gave as fairly similar to longicornis but more robust and larger, with a more rectangular head (without the mandibles), with the eyes smaller and set further forward; scapes surpassing the occiput by about half their length; a stouter alitrunk, with a more convex propodeum; joints, tarsi and mandibles yellowish [colouration like in vagabunda]. The similarity of the descriptions suggests P. birmana could well be synonymous with P. vagabunda.
A dark brown specimen of P. bourbonica from Hawaii is shown on http://www.discoverlife.org/mp/20q?search=Paratrechina+bourbonica
Emery (1892b) added that the Pr. currens Motschoulsky observed from the hothouses of Europe seemed to match Pr. longicornis Latr. [Prenolepis longicornis, as in Emery 1887a]. Emery also synonymized Formica vagans Jerdon, 1851, with Prenolepis longicornis.
I show (right) a specimen of P. longicornis from Egypt (from among specimens I have from ten countries). From Motschoulsky's note, currens was perhaps only 2 mm long (smaller than vagabunda) more slender and lighter and found on plants. Paratrechina longicornis specimens wherever they are found are 2.5-3 mm long, the same as if not longer than vagabunda. Their colour is variable but commonly they are dark brown, sometimes near black, and often with a distinct blue irridescence.
Emery, in fact, noted the P. currens observed by that author (Motschoulsky) in the hot houses of Europe seemed to = P. longicornis Latr. Note Emery wrote “mi pare” and not as he did for Formica vagans Jerdon, 1851, "mi pare indubbiamente" or of other species, “senza alcun dubbbio, identica” (without any doubt). The paler smaller species found in northern hothouses was most likely to have been Paratrechina vividula, described by Nylander (1846a) from hothouses in Helsinki and in Russia. At that time Finland was part of Imperial Russia.
Motschoulsky compares his new genus to Tapinoma. The only species then described and with which Motschoulsky is likely to have been familiar is Tapinoma erraticum Latr. It is the sole species listed by André (1881: 323) in his Catalogue of the ants of Europe and Algeria.
He, however, followed the Paratrechina descriptions with "Tapinoma albitarse" also from Ceylon. Bolton (2007: 68) cites the synonymy of that with Technomyrmex albipes (F. Smith) by Emery (1893: 249) and notes "(Type-depository not known; no types known to exist)". A syntype specimen can be seen at http://www.antweb.org/specimen.do?name=casent0103002
Curiously, Motschoulsky mentions Tapinoma as having a median notch to the anterior margin of the clypeus whereas Technomyrmex albipes and the Genus Paratrechina have no such notch.
The listing on page 95 of Motschoulsky V D, (1868). Genres et Especes d'Insectes publies dans differents ouvrages., Horae Societatis Entomologicae Rossicae. Supplement au vi Vol. St. Petersburg, is as follows:
B. 1863, III, p. 13.
vagabunda. Ceylan. 1863, III, p.13.
currens. Ind. or. B. 1863, III, p.14.
This shows a) the priority of the species names and b) that there was no earlier publication of the name currens.
Emery (1906b) considered Prenolepis vividula Nyl. and the classification of species of the genus Prenolepis. This confuses the situation as Emery opened by saying the ant which is the object of this note was described by Nylander after examples captured in the hot houses of the botanic garden in Helsinki (Helsingfors). Emery examined the Nylander type specimens and gave a clear illustrated description of Pr. vividula. He also had examined specimens from hot houses in Munich, Germany, that appeared identical to the Nylander type. From that he erected the new subgenus Nylanderia. The genus Prenolepis s. str. had the type species Pr. imparis Say (from the USA). He also defined subgenus Euprenolepis, type species Pr. procera Emery (from New Guinea). He made no mention of Paratrechina or Motschoulsky's paper (presumably because he considered it to be a junior synonym of Prenolepis, as in Emery, 1892b).
Wheeler (1911f) compiled an unqualified list of type forms including p 170) - Paratrechina Motschoulsky, 1863 (= Prenolepis). Type: Paratrechina currens Motschoulsky = Formica longicornis Latreille (monobasic). In the same list (p 168) he also gave "Nylanderia Emery (Subgenus of Prenolepis)". In his preamble, Wheeler noted he firmly believed "the subgenus as well as the subspecies and variety is, at least heuristically, a useful and valid category". He noted also that for a few obscure and antiquated sources he relied on Dalla Torre's catalogue.
In his catalogue of African and Malagasy ants (compiled up to January 1st 1920, published 25 October 1922) Wheeler used Prenolepis (Nylanderia) for almost all the species, including longicornis. The exception was Prenolepis (Prenolepis) kohlii Forel, 1916. His key (p 698) had the genus Prenolepis with three subgenera, Prenolepis, Nylanderia and Euprenolepis. A comment one has to make about Wheeler's lists is that, as he himself stated, "except in a very few instances the references have been checked up with the original papers by Dr. Bequaert". Bequaert appears to have had a primary interest in ant-plant relations and was not a taxonomist.
Wetterer (2008) made a historic study of Paratrechina longicornis and this reveals the earliest reports. For instance Santschi (1920h) on the ants of Indo-China listed Prenolepis longicornis Latr. Arnold (1922) also used Prenolepis for the two species from southern Africa.
The defining separation appears to be that of Emery (1925b: 212 ff). In his own Catalogue, the Tribe LASIINI (Ashmead) was emended to contain five genera - Pseudolasius Emery, Paratrechina Mostchoulsky, Myrmecocystus Wesmael, Prenolepis Mayr and Lasius Fabricius. Emery gave an illustration of the "Paratrechina longicornis" worker. In his introduction to the Genus Paratrechina Motschoulsky, the type species was given as "P. currens, Motschoulsky = Formica longicornis, Latreille". He then separated 1. Subgenus Paratrechina Motschoulsky, with a single member species P. longicornis; and 2. Subgenus Nylanderia Emery, type P. vividula Nylander. Emery included P. vagabunda Motschoulski in this subgenus.
Emery gave a key to separate the LASIINI genera: [additions from Emery's genus characters]
Note: Palaearctic Myrmecocystus now are separated as Cataglyphis.
Emery gave no argument to support his sudden use of Paratrechina but, from his citation of the genus history, one can deduce he followed the use of "Paratrechina longicornis Fabr." and "Paratrechina (Nylanderia) yerburyi Forel" by Wheeler (1921e: 112, published August 1921) in a simple listing of ants found in Canton, China. This itself was an unexplained change from the, at that time unpublished, catalogue and keys in the "Ants of the American Museum Congo expedition". It is particularly peculiar that Emery, who earlier had commented on Motschoulsky's definition and descriptions (Emery, 1892b), did not comment on, let alone correct, Wheeler's clearly erroneous designation of the type species.
Santschi (1929e) used the name Paratrechina longicornis in a listing of species from Morocco.
Wheeler (1936b: 210) is attributed with raising Nylanderia to genus rank but he gave no justification, simply using the name in listing three species of ant from the Haiti and the Dominican Republic, together with Paratrechina longicornis. One was a new species, Nylanderia darlingtoni, which Wheeler noted as "more like a Prenolepis than a Nylanderia". As noted above, however, Wheeler regarded the subgenus as a useful category and possibly, as in his 1911 list, he used Nylanderia in that sense rather than as a genus.
Creighton (1950a: 402ff), in his "Ants of North America", used the nomenclature Paratrechina (Paratrechina) longicornis for that species and Paratechina (Nylanderia) for several species. His key to the species separated P. longicornis as "Antennal scapes at least as twice as long as the head; body with distinct blue or violaceous reflections". The American P. (Nylanderia) had scapes less than twice as long as the head and body without violaceous reflections.
Trager (1984: 53) stated "The name Paratrechina was first used in the combination P. currens Motschoulsky (1863). The species name was not used for over sixty years, until Emery (1925) published his treatise on the formicine genera". Agosti & Bolton (1990a) cited the designation by Wheeler (1911: 170) of Paratrechina currens Motschoulsky as the type species. They also used or introduced the concept of "the vividula-group of Paratrechina. which is here taken as including all of Paratrechina except the longicornis-group".
The International Code of Zoological Nomenclature is quite clear on the designation of type species. It can be argued that the designation of P. longicornis as the type species by Wheeler (1911) meets the criterion in “Article 69. Type species not fixed in the original publication” but the key requirement is that the designation has to be valid in all other respects (69.1.2). Recommendation 69A states: “In designating a type species for a nominal genus or subgenus, an author should give preference to a species that is adequately described or illustrated, or of which type material still exists, or of which material is easily obtained”. Appendix B of the Code, General Recommendations, states: “An author, when drawing up the description of a new nominal taxon, should include comparisons with appropriate related taxa in order to assist later identification of the taxon. Name-bearing type material should be illustrated (or a reference given to such illustration)”. Even if one could be certain P. currens and P. longicornis are the same, the description of P. currens surely is neither adequate nor illustrated. P. vagabunda in contrast, was quite well described and illustrated, albeit poorly. Further, 69A.5. “If more than one group of species is recognized in a nominal genus-group taxon, preference should be given to a nominal species that belongs to as large a group as possible”. Given the validity of P. longicornis as representative of a monotypic genus-group, as suggested by LaPolla et al., that rules it out as the type-species. Lastly and perhaps very significantly, 69A.10. “All other things being equal, preference should be given to the nominal species cited first in the work, page or line ("position precedence")”.
Wheeler (1911) perhaps could be defined as a "First Reviser", as defined by the Code (Article 24.2), but that states "When the precedence between names or nomenclatural acts cannot be objectively determined, the precedence is fixed by the action of the first author citing in a published work those names or acts and selecting from them". Wheeler gave no reasons for his selection from Motschoulsky 's (1863) paper and (as shown above) the precedence can be objectively determined from the descriptions given by Motschoulsky and in his 1868 list.
There are provisions in the Code for older names to be used if synonymy can be shown or there is a long-standing accepted name [in this instance the two Motschoulsky species were both regarded as Prenolepis by Dalla Torre]. Wheeler (1911) perhaps could be defined as as a "First Reviser", as defined by the Code (Article 24.2), but that states "When the precedence between names or nomenclatural acts cannot be objectively determined, the precedence is fixed by the action of the first author citing in a published work those names or acts and selecting from them". Wheeler gave no reasons for his selection from Motschoulsky's paper and (as shown above) the precedence can be objectively determined from the descriptions given by Motschoulsky.
Assuming a reasonable degree of accuracy, the Motschoulsky description and drawing, of what has to be taken as his intended type species, clearly is not of Formica/Prenolepis/Paratrechina longicornis. The antennae and legs are far too short relative to the body and the alitrunk is too short and thick (Motschoulsky used the term subelongate). Add to that the Emery (1892b) comment on P. vagabunda being close to vividula and the logical conclusion is that the Motschoulsky genus in fact is what LaPolla et al. denote as Nylanderia, with the genus name pre-dating the latter by over 60 years. The error clearly stems from the Wheeler (1911f) choice of Paratrechina currens Motschoulsky as the type species. P. currens, however, was included as an aside by Motschoulsky in a paper otherwise almost exclusively describing insect species from Ceylon (Sri Lanka). As Wheeler seems never to have given justification for his taxonomic decisions, it is impossible to judge why he made that choice. My suspicion is that he simply relied on Dalla Torre's catalogue and did not study the original Motschoulsky paper. Emery (1892b) certainly had doubts, merely suggesting P. currens and P. longicornis were synonymous. What genus name one should use for Formica longicornis Latreille, 1802, is unresolved. The type species of Prenolepis was originally named Tapinoma nitens Mayr (1853a: 144) and was designated as the Prenolepis type by Mayr (1861: 52).
The following provisions of the Code apply: Article 70.3.
Misidentified type species. If an author discovers that a type species
was misidentified, the author may select, and thereby fix as type
species, the species that will, in his or her judgment, best serve
stability and universality, either
Paratrechina genus definition
In agreement with LaPolla et
al. (2010a) for “Nylanderia”
plus additions. Mandible with 6 to 7 teeth; maxillary palps
6-segmented; labial palps 4-segmented; erect setae on dorsum of head
randomly placed; typically with abundant erect setae on head, scapes,
legs and dorsum of alitrunk (mesosoma), although a few species lack
erect setae on head, scapes and legs. Eyes typically well developed and
placed midlength and laterally on head. Dorsal alitrunk setae arranged
loosely in pairs. Propodeum lacking erect setae (with one exception),
with a low- to high-domed dorsal face and with distinctly raised
spiracle set almost at the border of the declivity. Overall alitrunk
shape generally compact.
Pseudoparatrechina genus definition
In agreement with LaPolla et
al. (2010a) for “Paratrechina”
plus additions. Mandible with 5 teeth; maxillary palps 6-segmented;
labial palps 4-segmented; erect setae on dorsum of head randomly
placed; scapes lacking erect hairs; abundant erect setae on legs and
dorsum of alitrunk. Eyes well developed and convex, surpassing outline
of head in full frontal view, placed midlength and laterally on head.
Ocelli small but distinct (addition). Dorsal alitrunk setae arranged
loosely in pairs. Propodeum with a low-domed dorsal face, lacking erect
setae and without raised spiracles. Overall alitrunk shape long and
Note: An anonymous reviewer has put it that Paratrechina
longicornis has been accepted as for almost one hundred years as
the type species. Also, that the synonymy of P. currens with P. longicornis has never been
questioned. In fact, Emery (1892b) was not definitive,
using the worrds mi pare,
translating as it
seems. The simple truth is that, prior to LaPolla et al. (2010a), nobody
has published a global evidence-based review of the genus.
Wheeler (1911) gave a list of names and Emery (1925) was a catalogue.
The genus name Acantholepis
Mayr, 1861, was in universal myrmecological
use until Pagliano & Scaramozzino (1990: 4) came across prior use
of the name for a genus of plants. Bolton (1995: 33) designated the
genus name Lepisiota as the
first available replacement name. The longevity of use of Acantholepis was no hindrance.
After reading LaPolla et al (2010a), I wrote to Dr LaPolla: “As a leading question, you are adamant about the type species of Paratrechina but have you sighted the original Motschoulsky specimens? It seems quite clear to me, from his description and (albeit poor) drawing, that his type species was “Paratrichina vagabunda”. That Emery (1892b:8) said was a form close to Prenolepis vividula. The unqualified designation by Wheeler (1911f) of the type as being Para. currens = Formica longicornis appears to me to be completely wrong” (Taylor email January 20th, 2010).
Dr LaPolla did not reply and I submitted a first manuscript version of this page to a leading specialist journal on February 5th, 2010. The editors declined to publish the paper (by email 11th March, 2010). The key premise of the reviewers was that the designation by Wheeler (1911) was correct in accordance with ICZN Article 69 and that it was accepted for almost one hundred years. After the publication of LaPolla et al. (2010c), I wrote again to Dr LaPolla and also sent him a revised manuscript (emails 11th May, 2010). He responded with a copy of LaPolla et al. (2010b) and the remark: “I have rectified this potential problem. Please see the paper attached which was published [last] month. This will hopefully clarify any problems with the nomenclature”.
Referring to “some confusion regarding the type species for the genus Paratrechina”, LaPolla et al. (2010b) selected a worker ant specimen from Bangkok, Thailand, and designated that as a neotype of P. currens. Presumably they chose a South Asian specimen in reliance on Bolton (1995: 313), where the type location of P. currens was given wrongly as Sri Lanka. Motschoulsky stated P. currens was from “nos serres chaudes”, that is hothouses in Moscow where he lived. LaPolla et al. continued “it matches P. longicornis” and so we consider it a junior synonym of that species. Apart from a monochrome photograph of an obvious specimen of P. longicornis (e.g. the lateral view is an exact match of P. longicornis for the drawing in Smith, 1947), they gave no description and no comparison with the single sentence by Motschoulsky. Their specimen exactly matches that in my illustraion above and has a total length ca 2.5 mm, i.e. contrary to Motschoulsky, who gave it as smaller than P. vagabunda. The specimen differs from the Motschoulsky genus description on almost all key characters. Ocelli are prominent on the head whereas Motschoulsky expressly stated head without ocelli. The first and second segments of the funiculus are of equal length but Motschoulsky gave the first segment as longer than the second. The gaster is sub-globular (the Latreille,1802, definition of longicornis gave the gaster as globular) but Motschoulsky gave the gaster as triangularly acuminate posteriorly. LaPolla et al. (2010b) state that Emery (1892) synonymized P. currens under P. longicornis but that is not the case. Emery simply thought the two species were similar, writing “mi pare” (it seems to me). LaPolla et al. (2010b) also remarked that since that time no author has questioned the validity of this synonymy. Only one prior author (Trager, 1984) had made a comparative study of Paratrechina and that was limited to continental USA. Trager perpetuated the error of Wheeler (1911), writing “The name Paratrechina was first used in the combination P. currens Motschoulsky (1863)” whereas the real first use was in the combination P. vagabunda, confirmed by Motschoulsky (1868). An extensive search of the literature gives no indication of anyone, apart perhaps from Emery (1892), ever having read Motschoulsky (1863).
To conclude, LaPolla et al. (2010b) have chosen a specimen of one well-known species, designated it as a neotype of a cursorily defined second species, and then synonymized the two. They stated this action was under Article 75.1 of the ICZN Code. Perhaps so but they failed to comply with Article 75.3.5 and did not provide “evidence that the neotype is consistent with what is known of the former name-bearing type from the original description and from other sources”. I believe this neotype should be set aside in compliance with Article 75.2 “Circumstances excluded. A neotype is not to be designated as an end in itself, or as a matter of curatorial routine, and any such neotype designation is invalid”. From my personal position, they also did not follow “Recommendation 75B. Consultation with specialists. Before designating a neotype, an author should be satisfied that the proposed designation does not arouse serious objection from other specialists in the group in question”.
Posted 24 May 2010.
Now, October 2014, the situation remains unresolved. Some three years ago, I learnt the type specimens of P. currens (5 specimens) and P. vagabunda (1 specimen) had been located in the Zoological Museum of Moscow State University, by the Curator, Dr Elena Fedoseeva, and sent to Dr LaPolla, in 2010 and acknowledged by J S Lapolla in September 2012.
I asked through a Russian friend because I had been sent
specimens from Sri Lanka (Ceylon) and collected in the same general
area as P. vagabunda that appeared to meet the Motschoulsky description. My species page is at Paratrechina vagabunda.
2007, 2009, 2010, 2011, 2012, 2014 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.