Abstract:Abstract. Archaeochlus, a plesiomorphic genus of Podonominae (Chironomidae), is revised and two new species (biko from Namibia and brundini from southwestern Australia) described. The systematic status of the genus and the tribe Boreochlini is reassessed. Biogeographic evidence, sustained by a fossil record, dates the genus at least to the Upper Jurassic. The ecology of early Chironomidae is suggested to be eurythermic and hygropetric rather than cold stenothermic in lotic waters.
“…Until now, only the chironomid Archaeochlus, which occurs in small temporary streams on granite outcrops in south-western Australia and is also known from the Drakensberg Escarpment and Namibia in southern Africa, was recognized as a Gondwanan relic in arid parts of Western Australia (Edward, 1986;Cranston et al, 1987). The occurrence of aquatic invertebrates, hitherto known only from South America, in the southern Carnarvon Basin raises the possibility that Gondwanan relics may occur quite commonly in arid areas.…”
-Fifty-six sites, representing 53 wetlands, were surveyed in the southern Carnarvon Basin in 1994 and 1995 with the aim of documenting the waterbird and aquatic invertebrate fauna of the region. Most sites were surveyed in both winter and summer, although some contained water only one occasion. Altogether 57 waterbird species were recorded, with 29 292 waterbirds of 25 species on Lake MacLeod in October 1994. River pools were shown to be relatively important for waterbirds, while many freshwater claypans were little used.At least 492 species of aquatic invertebrate were collected. The invertebrate fauna was characterized by the low frequency with which taxa occurred: a third of the species were collected at a single site on only one occasion. Patterns of occurrence were not strongly seasonal. Many undescribed species were found and many range extensions were. recorded, reflecting lack of previous aquatic invertebrate work in the region. The level of regional endemicity could not be assessed adequately, although it is probably comparatively low. In terms of their invertebrate fauna, five types of wetlands were distinguished: river pools, rock pools and larger flowing streams; seeps, springs and smaller creeks; freshwater claypans; birridas; and Lake MacLeod. Environmental factors to which invertebrates appeared to respond were ratio of calcium/ alkalinity, total dissolved solids, turbidity, colour, flow, longitude and nutrients, although some factors were inter-correlated.Additional surveys should find extra species of waterbird and, more particularly, aquatic invertebrate using wetlands of the southern Carnarvon Basin. For many invertebrates, occurrences are too sparse for effective protection of species within a nature reserve system and other mechanisms will be required to ensure their conservation. Comparison of site classifications based on waterbird, aquatic invertebrate and plant data showed patterns among sites identified using one element of the biota did not reflect patterns shown by other elements. This suggests that, until further work has identified an element that reflects the whole wetland community, as many biotic elements as possible should be surveyed.
“…Until now, only the chironomid Archaeochlus, which occurs in small temporary streams on granite outcrops in south-western Australia and is also known from the Drakensberg Escarpment and Namibia in southern Africa, was recognized as a Gondwanan relic in arid parts of Western Australia (Edward, 1986;Cranston et al, 1987). The occurrence of aquatic invertebrates, hitherto known only from South America, in the southern Carnarvon Basin raises the possibility that Gondwanan relics may occur quite commonly in arid areas.…”
-Fifty-six sites, representing 53 wetlands, were surveyed in the southern Carnarvon Basin in 1994 and 1995 with the aim of documenting the waterbird and aquatic invertebrate fauna of the region. Most sites were surveyed in both winter and summer, although some contained water only one occasion. Altogether 57 waterbird species were recorded, with 29 292 waterbirds of 25 species on Lake MacLeod in October 1994. River pools were shown to be relatively important for waterbirds, while many freshwater claypans were little used.At least 492 species of aquatic invertebrate were collected. The invertebrate fauna was characterized by the low frequency with which taxa occurred: a third of the species were collected at a single site on only one occasion. Patterns of occurrence were not strongly seasonal. Many undescribed species were found and many range extensions were. recorded, reflecting lack of previous aquatic invertebrate work in the region. The level of regional endemicity could not be assessed adequately, although it is probably comparatively low. In terms of their invertebrate fauna, five types of wetlands were distinguished: river pools, rock pools and larger flowing streams; seeps, springs and smaller creeks; freshwater claypans; birridas; and Lake MacLeod. Environmental factors to which invertebrates appeared to respond were ratio of calcium/ alkalinity, total dissolved solids, turbidity, colour, flow, longitude and nutrients, although some factors were inter-correlated.Additional surveys should find extra species of waterbird and, more particularly, aquatic invertebrate using wetlands of the southern Carnarvon Basin. For many invertebrates, occurrences are too sparse for effective protection of species within a nature reserve system and other mechanisms will be required to ensure their conservation. Comparison of site classifications based on waterbird, aquatic invertebrate and plant data showed patterns among sites identified using one element of the biota did not reflect patterns shown by other elements. This suggests that, until further work has identified an element that reflects the whole wetland community, as many biotic elements as possible should be surveyed.
“…Several recent authors have sought to explain the relictual occurrence in southwestern Australia of invertebrates, particularly arthropods with African/Australian affinities, through geoclimatic history and plate tectonics theory, notably Cranston et al (1987) for the midge Archaeochloss and Main (1991) for the trapdoor spider Moggridgea. More recently Main (1996a) has interpreted the speciation of ancient mygalomorph (trapdoor spider) genera on the Yilgarn Plateau of southern Western Australia in relation to isolation along the ridges (watersheds) separating Mesozoic drainage lines.…”
“…Bayly (1997) and discuss the diversity and uniqueness of invertebrate assemblages occupying aquatic habitats on these outcrops. Most of these other invertebrates occupy pools rather than seepages, with the significant exception of the chironomid genus Archaeochlus, which, like the phreodrilids, appears to have a global distribution indicative of a Gondwanan origin (Cranston et al, 1987;Edward, 1989). Both these and the phreodrilids may have preferentially survived on granite outcrops as the south-west became increasingly arid from the midTertiary.…”
-Two new species of Phreodrilidae are described from habitats and regions of Western Australia from which the family has not previously been recorded. Phreodrilus peniculus sp. nov., the first phreodrilid to be described from north-western Australia, is characterised by a very short pseudopenis terminating in a small papilla at the apex of a long invagination of the body wall. This and other Phreodrilus with coiled pseudopenes are shown to have the pseudopenes and sometimes part of the atria ciliated. Astacopsidrilus edwardi sp. nov., which inhabits temporary seepages on granite outcrops of the inland south-west, has a swelling on the spermathecal ducts and often has replicated spermathecal chaetae. Additional records are provided for some previously recorded species.
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