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.