The Wagner Parsimony using morphological characters: a new method for palaeosynecological studies

Abstract

Abstract. The limits and diffi culties related to the tools currently in use for palaeosynecological comparisons of faunas or fl oras of different geological periods are discussed. The new method of the Wagner parsimony Applied to Palaeosynecology Using Morphology (WAPUM method), is defi ned and tested on morphological characters gathered from two insect groups Odonatoptera and Thripida. The diffi culties related to the monophyly of the taxonomic groups used in the more traditional approaches are no longer a problem when using the WAPUM method. In the WAPUM a character is 'presence versus absence of species bearing a morphological structure'. The results obtained from use of the WAPUM minimize the number of changes among character states. Application of the WAPUM could reveal signals to confi rm or object the currently available scenarios for the global changes in the evolution of past diversity and disparity of organisms (major changes or global crises of diversity).Résumé. La parcimonie de Wagner sur base de caractères morphologiques : une nouvelle méthode pour les études paléosynécologiques. Les limites et diffi cultés inhérentes aux outils actuellement utilisés dans les comparaisons paléosynécologiques de faunes ou de fl ores de différentes périodes géologiques sont discutées. La nouvelle méthode de la parsimonie de Wagner appliquée à la paléosynécologie sur la base de caractères morphologiques (méthode WAPUM), est défi nie et testée à partir des caractères morphologiques de deux groupes d'insectes, les Odonatoptera et les Thripida. Les diffi cultés liées à la monophylie des groupes taxonomiques utilisés dans les approches plus traditionnelles disparaissent avec la méthode WAPUM. Dans l'approche WAPUM, un caractère est 'présence/absence d'une espèce portant une structure morphologique'. Les résultats obtenus à partir de la méthode WAPUM minimisent le nombre de changements d'état de caractères. Cet outil permet de tester les scénarios actuellement disponibles pour les changements globaux dans l'évolution de la diversité et de la disparité passée des organismes (changements majeurs ou crises globales de la diversité).

Diversification of insects since the Devonian: a new approach based on morphological disparity of mouthparts

“…The insect evolutionary history remains mainly analyzed on the basis of the documented families and orders, ignoring two inherent weaknesses 2 – 15 : the extensions and definitions of the fossil and recent families vary frequently depending on the authors, and the monophyly of fossil groups of high rank is difficult to establish (e.g., the ‘Grylloblattodea’, ‘Protorthoptera’, Meganisoptera, etc.) 16 , 17 (for discussion see 18 , Supporting Information).…”

Evidence for Insect and Annelid Activity Across the Triassic-Jurassic Transition of East Greenland

“…Perhaps the optimal climate zone for the vector insects moved further north with global warming, leaving Astartekløft on the fringes with less abundant insects of this kind. Recent analysis of Odonatan morphological change from the Permian through the Miocene using the WAPUM method however shows no groupings across the ETE, indicating no change in overall Odonatan diversity or abundance (Nel et al 2010). Additional evidence from terrestrial Mesozoic fossil floral and faunal assemblages is still needed to increase understanding of fossil ecosystems, food webs and co-evolution of plants and insects.…”

“…The end-Permian event divides the insects into two major faunas: the Paleozoic evolutionary fauna and the post-Paleozoic evolutionary fauna: the two being so distinct that major Triassic insect clades are more similar to modern ones than to Late Permian clades, just a few million years apart (Labandeira 2005). Another significant insect extinction event is sometimes reported to have occurred at the K-Pg boundary, the end-Cretaceous mass extinction, also congruent with other marine and terrestrial extinctions (e.g., see summary by Schulte et al 2010), although recent research shows that this event may have been minor in comparison with extinctions occurring between the Early and Late Cretaceous (Labandeira et al 2002;Nel et al 2010). Three additional insect extinctions (Late Carboniferous, Late Jurassic, and late Early Cretaceous) are however not synchronous with major events in the marine realm, but represent detectible decreases in an otherwise general trend of exponential increase in insect diversity since the late Paleozoic (Labandeira 2005).…”

“…With knowledge of the insect body fossil record and documentation of insect feeding damage in the geological record rapidly increasing, this and similar hypotheses can be tested. For example, hypotheses can be tested with the recently published methods of Nel et al (2010), who propose a new tool-the WAPUM method (Wagner parsimony Applied to Palaeosynecology Using Morphology)-to study paleontological changes by means of comparison of characters (absence/presence), i.e., reflecting insect morphology through time.…”

New morphological data from the Jurassic of Inner Mongolia confirms the damselfly aspect of Protomyrmeleontidae (Insecta: Odonatoptera)

“…), at the boundary between the Lower and the Upper Cretaceous, during the Albian-Cenomanian-Turonian. This period is crucial for a large turnover among the odonatopteran groups, perhaps in relation with the ecological and chemical changes in the freshwater ecosystems about 100 Myr ago (Nel et al, 2010).…”