key characters in the phylogeny and classification of

Current Research in Neuropterology. Proceedings of the Fourth International Symposium on Neuropterology . Bagn5res-de-Luchon, France, 1991. Canard, M., AspGck, H. & Mansell, M.W. (Eds). Toulouse, France, 1992. 4. 243 - 254.

Key characters in the phylogeny and classification of Palparini (Insecta : Neuroptera : Myrmeleontidae *)

Mervyn W. MANSELL Plant Protection Research Institute, Pretoria, South Africa

ABSTRACT

A revision of the antlion tribe Palparini is in progress. Potentially significant characters are assessed here as a prerequisite to a phylogenetic analysis of the tribe. Indications are that four major divisions may exist within the Palparini, although only three can presently be substan- tiated by autapomorphies. Each division comprises a number of species-groupslgenera, which are characterized by autapomorphic features. This account highlights and analyses some of the attributes leading to the delimitation of genera and species-groups : the latter will be given formal generic status in forthcoming publications.

Key words : Myrmeleontidae, Palparini, phylogeny, classification, morphology.

INTRODUCTION

The tribe Palparini comprises the largest and most attractive antlions, characterized by several distinct autapomorphies which clearly delimit the group and in- dicate that the palparines are monophyletic (MARK. 1954 ; MANSELL 1990). Des- pite their striking appearance, the systematics of Palparini is unresolved and com- plex for reasons previously outlined (MANSELL 1990), and a revision of the tribe is accordingly being undertaken. Two papers in the revisional series have already appeared (MANSELL 1990, 1992), with the former providing a detailed introduction to the palparines , including reasons for disregarding certain generic terms.

Twenty genera and 230 species and subspecies have been described during the past 234 years, but there are only about 100 valid species of Palparini (MANSELL 1990). They are distributed throughout the Afrotropical Region and along the

* see nomenclatural note p. 253.

243

M. W. Mansell

southern Palaearctic to the Oriental Region, with no vestige in Australia or the Americas. Southern Africa has been a major evolutionary centre for these remar- kable antlions, where over 40 species and at least ten genera occur. Any meaning- ful revision of the tribe must consequently focus upon this fauna.

The delimitation of genera remains the most intractable aspect of palparine systematics as existing genera are not based upon sound phylogenetic criteria, but are valid rather through serendipity - fortunate discoveries made by accident. Currently recognised groupings, as well as new genera, must hence be validated through diagnostic autapomorphies. It is crucial to base such a phylogenetic analysis upon all taxa, to include all possible character permutations, and not only on a few species as has recently been attempted (INSOM & C A W ~ 1988). A reassessment of existing genera, including a subdivision of the conglomerate genus Palpares Rambur, is thus a priority in any revision of the Palparini.

The objective of the present paper is to highlight and discuss some of the more important characters, and to illustrate how they can be interpreted to provide a working classification. This contribution stops short of defining the generic autapomorphies and naming the groups of species, except those comprising already recognised genera. The formal naming of the new genera, the synonymy of certain existing names, and consequently changed species combinations, are the subject of papers in preparation.

MATERIALS AND METHODS

The revision is based on extensive collections and data compiled over the past 15 years. During this time, all valid species and extant types have been examined, including dissections of genitalia and mouthparts. The southern African taxa have all been field-collected and several reared. Research has been carried out in the major European, British and southern African museums, particularly the National Collection of Insects in Pretoria, housing the author's collection which includes the most comprehensive assemblage of southern African Myrmeleontidae, with over 10 000 specimens.

Based on these sources, approximately 50 characters were identified as potentially significant and consolidated into a data matrix which is being analysed using two computer programmes employing the principle of parsimony. For the present discussion, the character combinations have been assessed manually and polarity assigned mainly through outgroup comparison. The relevant characters and their polarity are used here to arrange the Palparini into three classificatory levels : (1) tribe, (2) genus-gronps and (3) genera andlor species-groups.

DISCUSSION OF CHARACTERS

This initial evaluation indicates that the tribe Palparini can be divided into four divisions or genus-groups on the basis of two main characters : structure of the male ectoprocts and shape of the palpimacula (labial sense organ). These four divisions are each subdivisible into genera (or temporary species-groups), utilizing

Key characters of Palparini

characters such as male genitalia, form of the labial palps and palpimacula, structure of the head and eyes, and others.

Characters delimifing the tribe

At least seven apomorphic features are manifest in the tribe Palparini. 1. The recurrent vein in the hindwings (see MANSELL 1990 : fig. 43). 2. Usually large species with heavily marked wings. 3. Prothorax much wider than long. 4. Male ectoprocts elongated. 5. Gonarcus and parameres fused into a sclerotized cone-like structure. 6. Larvae with increased number of mandibular teeth. 7. Known larvae all have lancwlate fossoria on the eighth abdominal segment.

Characters (I), (2), (S), (6) and (7) are autapomorphic and delimit the tribe Palparini, the recurrent vein (1) being especially significant in demonstrating the monophyly of the palparines (MANSELL 1990). The characteristic wing markings (2), manifest in all Palparini, have probably developed relative to the increase in size of the palparine taxa. The wing patterns have evolved to camouflage these large nocturnal insects, as they are extremely cryptic when resting amongst plants with the wings closed. Even the few diurnal species are effectively camouflaged against predators when not in flight (MANSELL 1990, 1992). The fusion of the gonarcus and parameres into a rigid cone-shaped structure (5), with the development of heavily sclerotized shiny-black parameres and a prominent hump on the gonarcus (here termed the gonarcal bulla), lying medially just anterior to the parameres (Figs 14- 16), is prevalent in Palparini. Similar features occur sporadically in other Myrmelwntidae but are manifest in all palparines, enhancing their significance in the Palparini. The subsequent reduction of the parameres and gonarcal bulla (Figs 17-20) is a further advance in the more highly-evolved palparines. The reduction of the parameres and bulla is consequential to the development of the ectoprocts (Figs 3 -9 , as both structures function essentially as clasping appendages during mating. The more reduced the one, the more elaborate the other (except in Tomatares Hagen and the speciosus-group, discussed below). These are considered to be sound phylogenetic characters as they are probably more conser- vative, being little-influenced by environmental factors. Female genitalia offer few characters except for the presence or absence of the pregenitale (MANSELL 1992 : fig. 14). The absence of this sclerotized structure appears to be apomorphic, and correlates with those males in which the parameres are modified or reduced, a characteristic of the more advanced taxa. In the absence of males this female trait could be of some significance and will be used as an apomorphy (absence) or a plesiomorphy (presence) in phylogenetic analysis. An increased number of mandibular teeth in larvae (6) is considered apomorphic, as three is the prevailing condition in the majority of antlions, including the Stilbopterygini, which is possi- bly the sister-group of Palparini. Three mandibular teeth are also manifest in all known Ascalaphidae, the undisputed sister-taxon of Myrmelwntidae. Any devia- tion from this condition (three mandibular teeth) must be considered as an evolutionary development. Fossoria (7) were discussed by MANSELL (1990).

M. W. Mansell

Figs 1-3. Male ectoprocts o f : 1. Pamexis namaqua Mansell ; 2. Palpares speciosus (Linaeus) ; 3. P. libelluloides (Linnaeus) (after A s m K , H., ASPOCK, U. & HBLZEL 1980). Abbreviations : epr = ectoproct ; pa = paramere ; S8-S9 = sternites 8 and 9 ; T8-T9 = tergites 8 and 9.


Genus-group characters

Two main characters facilitate the arrangement of the tribe Palparini into four divisions. 8. Structure of the male ectoprocts. 9. Shape of the palpimacula.

Male ectoprocts are either cylindrical (forcipate) (Fig. 1) or variously modified (Figs 2-5). Cylindrical ectoprocts are considered plesiomorphic as it is the prevailing condition in most Myrmeleontidae with elongated male appendages, and also in Palparini. Ectopocts with swellings and lobes, or which are laterally compressed are apomorphic.

Round or oval palpimaculae (Figs 6-8) are also plesiomorphic by outgroup comparison as it is the usual simple condition in most other antlions. The development of the palpimacula into a slit (Figs 9-13) is apomorphic, and the degree of development of the slit is a significant character at the generic level. If these two features are considered together, four assemblages - here termed divisions - can be distinguished : division A in which both characters are manifest in the plesiomorphic state, division B in which (8) is apomorphic and (9) is plesiomorphic, division C in which (8) is plesiomorphic and (9) is apomorphic, and division D in which both are apomorphic.

Divisions B, C and D can be regarded as monophyletic groupings, whilst the genera comprising division A almost certainly represent a paraphyletic assemblage of monophyletic groups. These divisions will be further elucidated in forthcoming studies.

Genus and species-group characters

The four divisions of Palparini and their constituent genera, or species- groups, are listed in Table I. It includes all but a few of the species, whose status and systematic position remain uncertain.

Division A is enigmatic, as it is based on the plesiomorphic states of characters (8) and (9), although most of the genera and species-groups are clearly defined by autapomorphic features. No single autapomorphy has been found to asso- ciate them, unlike other three divisions. Tomatares is problematic as it is the only palparine taxon which has plesiomorphic ectoprocts (character 8) but completely reduced (apomorphic) parameres and gonarcal bulla (Fig. 19) complicating its taxonomic interpretation. Small eyes are apomorphic relative to all other antlions and separates the two endemic southern African genera Pamexis Hagen and Pa- mares Mansell from other palparines. These two are undoubtedly sister taxa (MANSELL 1990, 1992). The annulatus-group is difficult to define on the basis of adult characters, but the known larvae have five mandibular teeth, a useful character for delimiting the group. The monotypic Golapus Nav& manifests a number of autapomorphies, such as a six-toothed larva and a long-legged adult, which separate it from all other Palparini, but obscure the relationships of this southern

M. W. Mansell

African endemic. The tristis and sparsus-groups appear to be closely related, although the former is well defined by modified parameres. Members of the sparsus-group have a sensory bulla between the parameres, a character used by INSOM & CAW] (1988) to define the genus Pseudopalpares Insom & Cad but this is an insignificant character at generic level as it is manifest in only two species, being

Figs 4 & 5. Male ectoprocts of : 4. Stenares irroratus Navis ; 5 . Nosa tigris (Dalman).

248


absent from closely related taxa. Lachlathetes Navk is a clearly defined genus, based on genitalic and other features. The nyussanus-group is problematic in that it seems to be quite distinct on the basis of general appearance, but no definitive autapomorphy has yet been found to characterize the taxon which apparently comprises some of the most primitive palparines.

Figs 6-13. Labial palps of : 6. Pabares pukhellus Esben-Petersen ; 7 . P. caffer (Bunneister) ; 8 . Lachlathetes moestus (Hagen) ; 9 . P. karooanus P6ringuey ; 10. P. eleganrulus P6rin- guey ; 11. P. latipennis Rambur ; 12. P. immensus McLachlan ; 13. P. waken McLa- chlan.

M. W. Mansell

Division B is clearly demarcated by ectoprocts with an internal lobe. Nosa tigris (Dalman) has uniquely elongated ectoprocts with internal lobes, and a consequently reduced gonarcal bulla and parameres (Figs 5 & 17) and is quite distinct. The speciosus-group on the other hand has retained the plesiomorphic gonarcus and parameres despite the modified ectoprocts, illustrating yet another paradox in the Palparini .

Figs 14-20. Gonarcus and parameres of : 14. Pamexis namaqua Mansell ; 15. Palpares cata- ractae PLringuey; 16. Golafrus oneili (Wringuey) ; 17. Nosa tigris (Dalrnan) ; 18. Stena- res irroratus Naviis ; 19. Tomatares citrinus (Hagen) ; 20. Pabares walkeri McLachlan.

250


The taxa comprising division C have all retained the plesiomorphic ectoprocts and internal genitalia, although there have been some bizarre developments to the gonarcal bulla (e.g. Fig. 15). In this division, it is the labial palp and palpimacula which have undergone substantial change.

Two genera, Palpares and Stenares Hagen constitute division D, which probably includes the most highly evolved palparines. It is here that both the terrninalia and palpimaculae have undergone the most radical development, with massively developed ectoprocts, reduced parameres and gonarcus, and long labial palps with slits running to the tip or even over the apex of the palpomere.

Table I. The genera and species-groups comprising the four divisions of the tribe Palparini, the number of species in each in brackets, and their distribution.

DIVISION A

Tomatares Hagen Pamexis Hagen Pamares Mansell

annulatus-group Golafus NavPs

tristis-group sparsus-group Lachlathetes NavPs nyassanus-group

DIVISION B

speciosus-group Nosa NavPs

Afrotropical (excluding Madagascar), Oriental Endemic to South Africa (Cape Province only) Endemic to Namibia and South Africa (Namaqualand) Endemic to Namibia and South Africa Endemic to Namibia, Bostwana and South Africa Afrotropical Afrotropical Afrotropical Afrotropical (including Madagascar), Oriental

(6) Afrotropical (1) Afrotropical

DIVISION C

Tomatarella Kimmins (2) Afrotropical, Palaearctic Crambomorphus McLachlan (5) South Africa (Cape Province), Namibia ;

Botswana ; Madagascar imntemus-group (7) Afrotropical ; Palaearctic inclemens-group (6) Afrotropical (including Madagascar) ;

Palaearctic elegantulus-group (9) Afrotropical ; Palaearctic

DIVISION D

Palpares Rambur (3) Afrotropical ; Palaearctic Stenares Hagen (8) Afrotropical ; Palaearctic

DISCUSSION

A number of significant observations on the morphology, biogeography and phylogeny can be made from the above analysis. The two most important characters both show a persuasive evolutionary sequence : the palpimacula progresses from being a tiny round aperture in species in divisions A and B to a great slit extending around the apex in D, with all intermediate conditions manifest between these two extremes in division C. In the case of the terminalia, there is a progres- sion from simple short cylindrical ectoprocts to very long elaborate structures with lobes or swellings. Corresponding with this development of the ectoprocts has been a consequent reduction in the size of the parameres and gonarcal bulla, and apparently also to the female pregenitale. The utilization and correct interpretation of these character states are an important key in the resolution of palparine systematics.

Division A contains all the southern African endemic genera and many of the species unique to this region. It includes some Afrotropical species and a few from the Oriental Region. No Palaearctic taxa are present in this conglomerate. Division B contains only Afrotropical species, whereas division C comprises predominantly southern African and Afrotropical taxa, with a few from the Palaearc- tic Region. Division D, on the other hand, contains predominantly Palaearctic taxa, with a few from the Afrotropical Region and none from southern Africa. From this it is evident that the southern African palparine fauna is more closely related to those from India and Madagascar. Those of Palaearctic provenance include the most highly evolved members of the group, culminating in the genera Stenares and Palpares. This suggests a typical late gondwanian radiation for Pal- parini, where the southern African, Madagascan and Oriental taxa have largely retained characters (8) and (9) in the plesiomorphic state, but have developed other autapomorphic features. On the other hand, the northern Afrotropical and Palaearctic taxa have generally evolved these two characters whilst being conser- vative as regards others. It is possible to speculate that the common stem of Stil- bopterygini and Palparini originated in Gondwanaland and that the former tribe was separated with Australia and South America before the radiation of Palparini. This took place on the remnants of Gondwanaland, comprising Africa, Madagas- car and India, and that palparines subsequently spread from the Oriental and Afrotropical Regions into the Palaearctic.

ACKNOWLEDGEMENTS

My esteemed colleagues Prof. H. AsPiiC~c (Universitiit Wien), Dr U. A S ~ K (Naturhistorisches Museum, Wien) and Mr H. H ~ L Z E L (Briickl, bsterreich) have critically read the manuscript and their input is gratefully acknowledged.

REFERENCES

ASP-, H., AsP~CK, U. & H~LZEL, H. (unter Mitarbeit von H. RAUSCH) 1980. Die Neuro- pteren Europas. Eine zusmenfassende Darstellung der Systernatik, Okologie und Cho-


rologie der Neuropteroidea (Megaloptera, Raphidioptera, Planipennia) Europas. 2 vols, 495 & 355 pp. Goecke & Evers, Krefeld.

INSOM, E. & C M , S. 1988. Taxonomic studies on Palparini (sensu Markl, 1954). I : The genus Palpares Rambur, 1842 partim (Neuroptera : Myrmeleontidae) with the proposal of its division and description of new genera. Neuroptera International 5 : 57-78.

MANSELL. M.W. 1990. The Mvrmelwntidae of southern Africa : tribe Pal~arini. Introduction and' description of ~ama>es gen. nov., with four new species (~nskcta : Neuroptera). Journal of the Entomological Society of Southern Africa 53 : 165-189.

MANSELL, M.W. 1992. The ant-lions of southern Africa : genus Pamexis Hagen (Neuroptera : Myrmeleontidae : Palparinae : Palparini). Systematic Entomology 17 : 65-78.

MARKL, W. 1954. Vergleichend-morphologische Studien zur Systematik und Klassifikation der Myrmeleoniden (Insects, Neuroptera). Verhandlungen der Natur$orschenden Gesells- chaji in Basel 65 : 178-263.

Address of author :

Dr Mervyn W. Mansell Biosystematics Division Plant Protection Research Institute Private Bag X134 Pretoria 000 1 Republic of South Africa

APPENDIX

Nomenclatural note : Myrmeleontidae vs Myrmeleonidae

During the editing of these Proceedings a number of fundamental questions have arisen with regard to the derivation and correct implementation of established names. The most perplexing was the uncertainty surrounding the terms Myrme- leontidae and Myrmeleonidae, as both frequently appear in the literature. The ambiguity arose from the similarity of the Greek word A&wv and the derived Latin leo. The word M y m l e o n is derived from Greek. The Greek Mwv is in the third declension and becomes Mvr-os in the genitive case, consequently resulting in Myrmeleontidae. This also applies to other names within the family-group, e.g. Myrmeleontidae, Myrmeleontini, Dendroleontini, Nesoleontini, Nemoleontini etc.

The term Myrmeleoninae is derived from an incorrectly formed stem, and although previous editions of the International Code of Zoological Nomenclature have permitted this, if the name was in general use, the latest version (1985) makes no provision for acceptance of such incorrectly derived terms. The term Myrmeleontidae is henceforth the only permissible name for the family, as used throughout these Proceedings.

M. CANARD, H. A S W K & M. W. MANSELL (Editors)

Bibliography of the Neuropterida Bibliography of the Neuropterida Reference number (r#): 7298 Reference Citation: Mansell, M. W. 1992 [1992.06.??]. Key characters in the phylogeny and classification of Palparini (Insecta: Neuroptera: Myrmeleontidae). Pp. 243-254 in Canard, M.; Aspöck, H.; Mansell, M. W. (eds.). Current Research in Neuropterology. Proceedings of the Fourth International Symposium on Neuropterology (24-27 June 1991, Bagnères-de-Luchon, Haute-Garonne, France). Privately printed, Toulouse, France. 414 pp. Copyrights: Any/all applicable copyrights reside with, and are reserved by, the publisher(s), the author(s) and/or other entities as allowed by law. No copyrights belong to the Bibliography of the Neuropterida. Notes: File: File produced for the Bibliography of the Neuropterida (BotN) component of the Lacewing Digital Library (LDL) Project, 2011.

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