RESULTS
Redefinition of Parastephanellus Enderlein
The genus Parastephanellus is currently defined as having a radial cell relatively larger than the median cell (front wing). All other "diagnostic" characters found in the literature for this genus are also shared with Hemistephanus Enderlein. Since the relative size of cells M and R varies, misidentifications are frequent. In fact, Australian species of Parastephanellus have often been described3,5,7 or identified4,6 as Hemistephanus.
The following comparative table and illustrations summarize the differences between these two genera, and indicate the apomorphies supporting the genus Parastephanellus. The plus sign indicates the apomorphic state.
| Differences between Parastephanellus and Hemistephanus | |
| Parastephanellus | Hemistephanus |
| 1 Pronotal structure simpler | 1 Pronotum highly differentiated |
| 2 Mesonotum transverse | 2 Mesonotum semicircular |
| 3 Setae on M+Cu apical | 3 Setae on M+Cu subapical |
| 4 Veins 2+3Rs and Rs+M fused | 4 Vein 2+3Rs broken basally |
| 5 Pterostigma blunt | 5 Pterostigma acute |
| 6 Apical half 2+3M nebulous | 6 Vein 2+3M entirely tubular |
| 7 Ovipositor sheaths dark | 7 Sheaths pre-apically white |
Definition of Parastephanellus Species
The Australian species of Parastephanellus are usually difficult to differentiate, as most characters of taxonomic importance are not conspicuous, and show a high intra- and interspecific variation. These species share a complex general pattern of cuticular sculpturing, which must be well understood before a meaningful identification can be tried.
Recognition of species is even more difficult with males, for which strongly atypical specimens are not uncommon, and thus sometimes impossible to identify if not associated with the respective females. The collection of mating pairs is of obvious interest, but even these should be carefully studied, as intraspecific mating is not a far-fetched possibility (see Appendix).
Diversity, Distribution, and Endemism
Three genera and at least 22 species of Stephanidae occur in Australia: Megischus (2 spp); Parastephanellus (19 spp); and Schlettererius, represented by the imported S. cinctipes.
| Number of Species of Stephanidae in Australia. | |||
| Genus | Previously known | Undescribed | Endemic |
| Schlettererius | 1 | - | - |
| Megischus | 1 | 1 | 2 |
| Parastephanellus | 5 | 14 | 17 |
The stephanid fauna of Australia is almost entirely endemic. The general morphological structure of the species in the two native genera is also fairly characteristic, with subtle, but constant features which are unique for the Australian stephanids, suggesting these species evolved in strict isolation.
In Australia, stephanids seem to be distributed in two characteristic groups, one on the western side, and one on the eastern side, with no species known from the central part of the country. Only P. rufoornatus occurs on both sides. There are no records of native stephanids in Tasmania.
