Taxonomy, phylogeny, and zoogeography of the weevil genus Euops (Insecta: Coleoptera: Curculionoidea) in the Papuan Region

The attelabid genus Euops SCHOENHERR is demonstrated to constitute a monophyletic group based on the following synapomorphies: 1) mycetangia of the female for storage of fungus spores consisting of three different reservoirs and associated setose structures, 2) a patch of modified setae of the female venter, usually associated with exocrinous glands, 3) enlarged eyes. Systematics, evolutionary history and biology of Curculionoidea and Attelabidae are summarized. The "Papuan region" is treated herein as comprising the provinces of Maluku and Irian Jaya of Indonesia, Papua New Guinea, and the Solomon Islands. A summary of the natural history of this region is given. Approximately two years were spent in the field to supplement the sparse material available from museum collections for this study. Selected, monophyletic species groups of Euops are treated in a monographic way: the spinosus-group (ten species described as new), the pygmaeus-group (one species redescribed, 13 species described as new), the quadrifasciculatus-group (four species redescribed, six species described as new), the simulans-group (three species redescribed, 19 species described as new), and the subgenus Neosynaptops (two species redescribed, seven species described as new). These monographs are attached to the present summary as appendices. New standards are proposed for taxonomic descriptions of Euops species: the transfer apparatus of the male genitalia proved to be of critical importance for the diagnosis of species. Other characters of male and female genitalia, of the mouthparts, the metanotum, and the proventriculus are useful in phylogenetic reconstruction and in the diagnosis of species groups. These and other characters are described for the first time. Methods for their appropriate preparation and examination by SEM and light microscopy are proposed. The literature published on Euops is reviewed and a bibliography is given. At the commencement of this study (1998), 134 species and 10 subspecies of Euops were recognized as valid worldwide. A synopsis of Papuan Euops is given. Before the commencement of this study 24 valid species of Papuan Euops, based on inadequate descriptions, were known to science. These are redescribed to meet the new standards. Where necessary, lectotypes are designated. One species (E. picipes VOSS) is placed into synonymy. One subspecific name (Euops femoralis f. ruficornis Voss) is elevated to species level. 52 species are added by formal descriptions. At present (2002), 76 described species are reported for the Papuan region, constituting 40 % of the world fauna (189 described species). Another 108 undescribed species from the Papuan region are listed. These could not be described herein but they will be so in later publications. Thus, at present 184 Euops species are known from the Papuan region constituting 58 % of the world fauna (320 ascertained species). Cladistic analyses are performed for each of the monographed species groups. An overall analysis is done using selected species. Five other genera of Attelabidae were included as outgroup representatives. The monophyly of the recognized species groups of Euops was confirmed except for the simulans-group which is difficult to define at its base. A clade comprising Apoderus, Lamprolabus and Euscelophilus is supported mainly by derived characters of the prementum, plesiomorphic in Attelabus and in Euops. It is predicted that the rank of the "Apoderinae" will have to be downgraded after a phylogenetic analysis of the Attelabidae. The worldwide distribution of Euops is a paleotropical one. This could reflect an ancient Gondwanic pattern or a more recent one through rapid dispersal. Evidence for and against each hypothesis is discussed. Within the Papuan region most species groups of Euops are strictly confined to the area of the Sahul shelf. Off-shore islands, such as Maluku or the Solomons, have a depauperate fauna. The areas of endemism observed are usually not compatible with geological terrains. Rapid dispersal overland is postulated. The Philippines and Sulawesi adjoining to the West have a speciose but uniform fauna, belonging exclusively to the subgenus Suniops. The fauna of Maluku consists of equal parts of Suniops species arrived from the west and of other species of Papuan Euops groups from the east. There is little overlap between the Papuan fauna of Euops and a moderately rich Australian one. The origins of the highly secluded Papuan fauna of Euops remain obscure. Although Euops occupies an altitudinal range from sea level to 3535 m, there is a maximum of diversity between 700 m and 800 m altitude. Diversity remains at a high level to an altitude of 1600 m or further, with an increase in the endemism of species. This pattern is different from groups such as birds and ants, whose diversity decreases evenly along an altitudinal gradient. It is suggested that this fact should be considered in priority assessments for conservation measures. A table of the association with host plants is given. Species of the pygmaeus-group are reported to feed exclusively on the fresh leaf flush of Nothofagus. Species of its presumed adelphotaxon, the quadrifasciculatus-group, are recorded from Myrtaceae. Such a pattern is unusual among phytophagous insects and different scenarios for a host switch are discussed. Preliminary data on the association with fungi are provided. Fungi isolated from the mycetangia of different Euops species exhibit different mycological characters (e.g. coloration) and presumably belong to different species. They all belong to the genus Penicillium. It was found that spores obtained from the mycetangia can be stored for extended periods in sterilized water. Future studies should make use of this fact to export fungus samples and to cultivate them under more favourable laboratory conditions than usually available in tropical countries. A trend curve of the discovery of Euops species in the Papuan region is discussed. It reveals that the saturation phase is not yet reached. It is estimated that the area studied harbours at least 300 species of Euops, making it the most diverse region for this genus in the world.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Ludwig-Maximilians-Universität

Year

2002

Author dc:creator

• Riedel, Alexander

Repository record source_url

https://edoc.ub.uni-muenchen.de/62/

OAI identifier oai:identifier

oai:edoc.ub.uni-muenchen.de:62