James M. Carpenter and John W. Wenzel.
Synonymy of the genera Protopolybia and Pseudochartergus (Hymenoptera: Vespidae: Polistinae).
Psyche 96:177-186, 1989.

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SYNONYMY OF THE GENERA
PROTOPOLYBZA AND PSEUDOCHARTERGUS
(HYMENOPTERA: VESPIDAE; POLISTINAE)*
BY JAMES M. CARPENTER AND JOHN W, WENZEL Museum of Comparative Zoology,
Harvard University,
Cambridge, MA 021 38
Protopolybia and Pseudochartergus are two genera of small paper wasps, both described by Ducke (1905a). They are clearly closely related, having the synapomorphy of a medial posterior pro- cess on the metanotum (Carpenter, 1990). Bequaert (1938) ques- tioned the validity of these taxa, but later (1944a) accepted Weyrauch's view that there are "fundamental differences" in nest architecture. The recognition of these genera as distinct has pre- vailed since, and published keys appear to allow their separation with ease (Bequaert, 1944b and slightly modified in Snelling, 1981; Richards, 1978). This appearance is an illusion; the characters pur- ported to distinguish the taxa simply do not. While engaged in phylogenetic studies on Polistinae (see Carpenter, 1990; Wenzel, 1990), we have independently come to the conclusion that neither morphology nor nest architecture support the recognition of two genera. It is our aim in this paper to establish the synonymy of these genera.
Ducke (1905a) established Protopolybia for five species: Charter- gus nitida Ducke, Polybia bella Ihering, Chartergus rufiventris Ducke (=emortualis (Saussure)fide Ducke, 1907), Polistes minutis- sirna Spinola and Polybia holoxantha Ducke. He stated that Pol- ybia pumila Saussure (=sedula (Saussure) fide Richards, 1978), picteti Saussure, nana Saussure (a Leipomeles; Ducke, 1907, and Richards, 1978) and laboriosa Saussure (unidentified; Richards, *Manuscript received by the editor October 11, 1989.



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178 Psyche [VOL 96
1978) also probably belonged in this genus, although he had not seen specimens. Bequaert (1944a) selected bella as the type species, and Bequaert (1944a) and Richards (1978) revised the genus. Richards (1978) recognized 23 species and two additional subspecies in Protopolybia.
Pseudochartergus was described for Charterginus cinctellus Fox (=chartergoides (Gribodo) jide Ducke, 1905 b, 1907) and C. fuscatus Fox. Bequaert (1938) selected cinctellus as the type species. Bequaert (1938) and Richards (1978) subsequently revised Pseudo- chartergus. In Richards' monograph five species and two additional subspecies are recognized.
These genera have been shown as closely related in the phyloge- netic diagrams of Ducke (19 10,lg l4), Richards (1978) and Carpen- ter (1990), and in the latter two they are each other's closest relatives. The strongest evidence for this is the medial posterior process on the metatnotum, a feature unique within Polistinae (Carpenter, 1990).
These genera were separated in Ducke's (1905a) morphological key by a couplet giving as alternatives: the clypeus much longer than wide and apically truncate, and the tempora extremely narrow (leading to Pseudochartergus) versus the clypeus not longer than wide and apically pointed, and the tempora variable but not extremely narrow (leading to Protopolybia). Ducke's later key (1910) separated these genera at the same couplet, adding the char- acters of the metanotum with a narrow dorsal surface and then vertically abrupt, and the metasoma always sessile (Pseudocharter- gus) versus metanotum uniformly oblique (Protopolybia). This con- stituted the first recognition that the two genera were closely related. Richards' (1 978) key added the distinguishing features of the scrobal sulcus very weak (Pseudochartergus) versus distinct (Protopolybia), but otherwise the published keys have used Ducke's characters. Richards' discussion of Pseudochartergus (1 978: 154) also men- tioned a "short, stout body" and short wide metanotal process as characteristic of the genus. In what follows each of these characters is discussed in turn. Specimens of all species except Protopolybia alvarengai, cameranii, iheringi, nitida, rotundata and rugulosa have



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been examined by JMC; they are deposited primarily in the collec- tion of the Museum of Comparative Zoology, and the US. National Museum of Natural History.
Clypeal apex
The clypeal apex is truncate in Pseudochartergus, with the trun- cation being wider than an ocellar diameter. This a derived state from the primitive one of a bluntly pointed apex, found in most Protopolybia and other related genera (Carpenter, 1990). This indi- cates monophyly of Pseudochartergus, but its strength as a distin- guishing feature is vitiated by the fact that it is approached in species of Protopolybia, including minutissima and scutellaris. The trunca- tion is somewhat narrower in these species than in Pseudocharter- gus, being aproximately an ocellar diameter. Furthermore, the clypeal apex is quite broadly rounded, almost truncate, in other species of Protopolybia, including chanchamayensis, exigua, holox- antha and rubrithorax. This indicates the continuous nature of the variation in this trait. Those Protopolybia with intermediate condi- tions may be more closely related to Pseudochartergus, but cladistic inferences based on continuously varying traits are often proble- matic (see Pimentel and Riggins, 1987). Whatever the case, this character is a poor diagnostic feature.
Clypeal proportions
The female clypeus longer than wide is supposed to characterize Pseudochartergus, but in duckeianus it is wider than long, and its length is really barely greater than its maximum width in the other species. Some of the species of Protopolybia have the clypeus much wider than long (emortualis, the picteti group), but most have it almost as long as wide, and in scutellaris it is actually longer than wide. The variation in the relative width of the clypeus played an important role in Bequaert's (1944a) key to species of Protopolybia, maintained to some extent in Richards' (1978) key, so not only is this character not diagnostic for either genus, it also varies continuously.
Tempora
The upper part of the female gena (tempora) "very narrow" is supposed to distinguish Pseudochartergus from Protopolybia, which has it "very broad" (Richards, 1978). This character has never been precisely described, but in Pseudochartergus the tempora is



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180 Psyche [vo~. 96
narrower than the eye in lateral view. Richards (1978: 154), while characterizing his new species duckeianus as "rather intermediate", stated that "but the gena is narrower than in Protopolybia". How- ever, while the gena is wider than the eye in lateral view in Protopo- lybia emortualis and the picteti group, other species have it narrower than the eye, and in scutellaris, sedula and weyrauchi it is no wider than in duckeianus. Not only is this feature variable within Proto- polybia, it varies within Pseudochartergus: fuscatus and pallidibal- teatus have it clearly narrower than the other three species. As with the clypeal proportions, not only is this character not really diagnos- tic for either genus, it also varies continuously. Metanotal process
Richards7 (1978) key characterized the metanotal process as short and broad in Pseudochartergus, versus long and tongue-like in Pro- topolybia. However, on p. 154, he stated that emortualis has the same condition. This is not actually correct; emortualis has it more rounded apically than any Pseudochartergus. On the other hand, in Pseudochartergus fuscatus the process is longer and narrower than in the other species, and in pallidibalteatus it is also quite narrow, although shorter. In Protopolybia holoxantha and minutissima the process is no longer or narrower than these two species of Pseudo- chartergus, and in scutellaris it is shorter and broader. The shape of the process varies considerably among the other species of Proto- polybia, and thus this character too is not diagnostic for either genus.
Metanotal dorsum
The metanotum is compressed in most of the species of Pseudo- chartergus, so that it slopes almost vertically into the propodeal concavity, and has a very short horizontal surface. This is derived in comparison to the state of a single oblique surface, as in most Pro- topolybia and other related genera (see Carpenter, 1990). However, Pseudochartergus duckeianus has the plesiomorphic condition, while Protopolybia emortualis has the derived state. This character thus diagnoses neither genus.
Scrobal sulcus
As mentioned in Richards' (1978) key, the scrobal furrow is very weak in Pseudochartergus. But it is not distinct in all Protopolybia: emortualis has it no stronger than Pseudochartergus. An evanescent



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scrobal furrow is a derived condition within Polistinae (Carpenter, 1990), and so this feature supports the monophyly of Pseudochar- tergus, but then also indicates paraphyly of Protopolybia, with emortualis evidently more closely related to Pseudochartergus. Mesosomal proportions
Most species of Pseudochartergus have a relatively robust meso- soma in comparison to Protopolybia, which may well be derived, but as noted by Richards (1978: 154) Protopolybia emortualis has the same condition. Furthermore, the mesosomal proportions in Pseudochartergus duckeianus are similar to the other species of Protopolybia. Again, this character diagnoses neither genus. Mesosomal segment I
In Pseudochartergus the first metasomal segment is said to be sessile, since it is broader than long and not petiolate. The polarity of this character at this level is unclear, since the sister-group of these genera is as yet unresolved, and the shape varies in the likely candidate genera (see Carpenter, 1990). In any event, the shape varies within Protopolybia, with exigua showing the same condition as Pseudochartergus. Most other species have the segment sessile, but narrower than in Pseudochartergus. As before, this character diagnoses neither genus.
As with most taxa, the nests are less well known than the animals. Reports in the literature are often too brief to be of value and critical elements are left undescri bed. Reliably determined nests of the following species have been examined by JWW (the collections containing critical specimens are identified below): Pseudocharter- gus chartergoides, fuscatus, pallidibalteatus, panamensis, Protopo- lybia acutiscutis, chanchamayensis, exigua, holoxantha, minutissima, picteti, sedula, scutellaris and weyrauchi. Considering that nests of only about half the species have been studied carefully by the same observer, we will no doubt need to revise our impressions of the distribution of given characters or the direction of character trans- formations when our knowledge is more complete. To date, Pseudochartergus has been characterized as building naked combs sheltered by curled or adjacent leaves, the natural cavity being closed by a clear, hard sheet of salivary secretion with-



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out vegetable fiber (Jeanne, 1970). Unlike most other neotropical genera, no paper envelope conceals the combs. In contrast, Proto- polybia bears a simple, domed, paper envelope from the margin of the comb, some species later expanding the nest by building new cells upon this envelope and covering them with another. In his discussion of the distinction between Pseudochartergus and Proto- polybia, Bequaert (1944) wrote, quoting a letter from Weyrauch: "There is, however, one fundamental difference between the two genera. Pseudochartergus builds no envelope whatsoever of plant fibers around the comb. Protopolybia on the other hand covers with a fibrous envelope all parts of the combs not otherwise protected. The ability to build a paper envelope or its lack mark among all social wasps such a fundamental bio- logical departure that in my opinion Protopolybia could not be regarded as a subgenus of Pseudochartergus." Thus, as has been traditional in polistine taxonomy, Bequaert relied in large part on architectural differences for generic separa- tion. Unfortunately, each of Weyrauch's declarations about the state of the envelope in these genera and about the importance of envelopes in social wasps is now known to be compromised. Firstly, Richards (1978) reports that Pseudochartergus pallidibalteatus builds a paper envelope quite like that of Protopolybia, and JWW has confirmed the observation for nests of this species (Rijksmu- seum, Leiden) as well as for another, unidentified one (Museum National, Paris). In addition to the sheet of clear secretion between leaves, Schremmer's (1984) photographs of two Pseudochartergus chartergoides nests show several important features. This species will build a paper envelope from the comb margin and cells upon it, both traits considered typical of Protopolybia (see Ducke's 1905a key). Also evident are the multiple entrance holes corresponding to successively built sections, a trait long believed unique to Protopo- lybia (Ducke, 1910; Richards, 1978). Consequently, at least two of the five currently recognized species of Pseudochartergus violate the architectural boundaries other authors believed to be valid. Secondly, Protopolybia scutellaris, in Colombia (Richards 1978) and Panama (Snow Entomological Museum, Lawrence, Kansas) do not build envelopes at all, but rather have a comb completely exposed beneath the broad leaves of Heliconia. Further contradict- ing the stereotype of a fibrous envelope in Protopolybia, acutiscutis,



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sedula, weyrauchi, and likely others, often fix leaves together with clear salivary secretion, or use copious amounts of it in regions where the fibrous envelope is fastened to leaves. Thirdly, recent studies have shown that an envelope or protective sheet has arisen or been lost independently in many lineages (Wen- zel, 1990). For the genera in question we can infer that presence of the envelope is the primitive state: only one of 23 swarm-founding, neotropical genera contains no species known to produce envelopes (Apoica). From this perspective, then, the fiber-free veil of Pseudo- chartergus can be interpreted as a loss or reduction of the more ordinary, fibrous, ancestral envelope. Such reduction is known to have occurred in other taxa that nest in cavities, including species in the widely separated genera Agelaia, Metapolybia, Polybioides, Vespa, and Vespula (Wenzel, 1990, and unpublished data). More strikingly, the Indomalayan Ropalidia opifex builds nests in natural cavities between leaves, just as the neotropical Pseudochartergus does, and joins leaves together with a transparent sheet of oral secretion devoid of vegetable fiber, just like Pseudochartergus (van der Vecht, 1962). Thus, it now appears that the traits in which Weyrauch had so much faith are neither as clearly segregated as he thought nor as deeply significant as indicators of phylogeny. The nests of Protopolybia and Pseudochartergus display a mosaic of ancestral and derived traits. Various presumably plesiomorphic characters appear in some Pseudochartergus and no Protopolybia. At least some nests of Pseudochartergus chartergoides (those with- out comb-borne envelopes), panamensis and fuscatus expand by gradually adding cells to the margin and elongating the cell walls as the larvae within grow larger, while Pseudochartergus nests bearing envelopes from the combs and nests of Protopolybia are expanded suddenly in large blocks of cells which are built to full height, the outermost wall becoming the envelope. Clearly, the first scheme is the primitive one displayed by most social wasps while the latter is derived.
Furthermore, Pseudochartergus appears to have no architectural autapomorphy since each trait is shared with at least some Proto- polybia. For example, using pure secretion to close gaps between leaves is derived within the clade of South American swarming wasps and conspicuous in Pseudochartergus (Jeanne, 1970). Yet, this trait is also seen in what seems to be a highly derived design in



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184 Psyche [vo~. 96
Protopolybia, such as that of acutiscutis (above), comprised of tens of thousands of cells, often with separate envelopes dissociated from the actual comb walls and expanding helically downward (Wenzel, 1990).
As shown by the foregoing, the recognition of two genera in this clade is untenable. Pseudochartergus sensu Richards may be a monophyletic group, as shown by the diagnostic apomorphy of an apically truncate clypeus, and supported by the non-unique evanes- cent scrobal sulcus. If these characters are accepted as synapomor- phies, Protopolybia is apparently paraphyletic; there are no apomorphies defining the genus, the truncate clypeus is approached in several species, and the evanescent scrobal sulcus found in another species (emortualis) which shares other derived features with some species of Pseudochartergus. The classification must then be adjusted to remove the paraphyletic taxon (Hennig, 1966). Yet some of the apomorphies shared by Protopolybia emortualis with species of Pseudochartergus conflict with the clypeal apex apo- morphy; Pseudochartergus duckeianus does not have the com- pressed metanotum or robust mesosoma. Thus, it may be that Pseudochartergus as presently constituted is not monophyletic, with duckeianus possibly misplaced (cf. Richards, 1978: 155). And if our inferences about nest architecture polarity are correct, this suggests Pseudochartergus may be paraphyletic but Protopolybia is mono- phyletic-the reverse of the morphological characters. In any event, most of the morphological characters show essentially continuous variation or are not diagnostic, while within a species of either of these groups, nests generally show far more variability than that found within species of virtually all the other neotropical swarming genera. Hence the diagnosis of two genera is dubious solely for these reasons. We are therefore synonymizing them. Protopolybia and Pseudochartergus were described in the same paper. The Principle of the First Reviser (Article 24 of the Interna- tional Code of Zoological Nomenclature) therefore applies in determining the relative precedence of these names. Bequaert (1938: 104) stated that he was "inclined to regard it [Protopolybia] as a subgenus only" of Pseudochartergus, but he did not take any explicit action. Accordingly, we are acting as first reviser, and select



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19891 Carpenter & Wenzel - Vespidae 185
Protopolybia as the name of this genus. The name appeared first in Ducke (1905a), on p. 7, with Pseudochartergus first mentioned on p. 8.
It should be noted that, as pointed out by Bequaert (1938), Polis- tella Ashmead (1904: 133), monotypic for Polistes manillensis Saus- sure, was based on misidentified specimens of Protopolybia exigua (see Richards, 1978, for species synonymy). Polistella is now treated as a subgenus of Polistes (e.g. van der Vecht, 1971; Richards, 1973). Under Article 70b of the Code it is to be referred to the Commission to designate as type species of Polistella whichever nominal species will in its judgement best serve stability of nomenclature. That clearly would be Polistes manillensis, despite the misidentification in the original designation. We will continue the established usage, rejecting Polistella as an available name for Protopolybia. The syn- onymy of this genus follows.
Protopolybia Ducke (1905a: 7,9, 17)
Type species Polybia bella von Ihering, 1904, by subsequent desig- nation of Bequaert (1944a: 97).
Pseudochartergus Ducke (1 905a: 8, 9, 15). Type species Chartergi- nus cinctellus Fox, 1898 (=Nectarha chartergoides Gribodo, 1891), by subsequent designation of Bequaert (1938: 103). NEW SYNONYMY.
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