Hemerodromiinae (Diptera: Empididae): a tentative phylogeny and biogeographical discussion

A cladistic analysis of adult morphological characters was used to hypothesize phylogenetic and zoogeographical relationships in Hemerodromiinae (Diptera: Empididae). Afrodromia Smith, Drymodromia Becker and an undescribed Chilean genus subtended a sister‐group relationship between the tribes Chelipodini and Hemerodromiini. Chelipodozus Smith and an undescribed Australian genus were supported only weakly in Hemerodromiini, and are regarded as incertae sedis within Hemerodromiinae. In Chelipodini, Anaclastoctedon Plant and an undescribed Australian genus subtended all others that form two sister‐group clades. (i) A widespread Chelipoda‐like group comprising Achelipoda Yang, Zhang & Zhang, Ptilophyllodromia Bezzi, Chelipoda Macquarts.s. and Phyllodromia Zetterstedt s.s. has a worldwide distribution, excepting the Afrotropical, considered to date from before or during the early phase of Gondwanan fragmentation. Phyllodromia s.s. is an exclusively Palaearctic genus of doubtful validity, to which Southern Hemisphere forms have been assigned incorrectly. Ptilophyllodromia Bezzi syn.n . is regarded as a junior synonym of Chelipoda, with the included species relegated to a species group. (ii) An austral Chelipoda‐like group confined to New Zealand, New Caledonia, Lord Howe Island and Vanuatu, includes Monodromia Collin and species currently incorrectly assigned to Chelipoda and Phyllodromia. The group is hypothesized as a relictual Gondwanan element that has survived Oligocene drowning as metapopulations persisting in situ on ephemeral islands along arcs, ridges and buoyant crustal blocks overlying hot spots in New Zealand and the Southwest Pacific. In the tribe Hemerodromiini, many Southern Hemisphere species assigned currently to Hemerodromia Meigen, Cladodromia Bezzi and Neoplasta Coquillett require reassignment. The sister‐group relationship between the southern African endemic Afrodromia and other Hemerodromiinae is viewed as evidence of early divergence of Hemerodromiinae and Empidinae by the early Cretaceous, pre‐dating major Gondwanan fragmentation. An assessment of fossil forms indicated that Chelifera detestata (Meunier) from Eocene/Oligocene Baltic amber is the only genuine described fossil representative of Hemerodromiinae.     

Rhizome Growth and Clone Development in Anemone nemorosa L.

Studies of natural populations indicate that clones grow radially,soon developing a hollow centre which may be invaded by newgenotypes. In the populations studied, individual rhizomes elongate byan average of 2.5 cm per year. Growth is sympodial, the terminalbud forming an aerial shoot and further elongation occurringfrom an axillary bud. The oldest rhizome segment found was 7 years with most rhizomesbeing 3 or 4 years old. Because there is no apparent senescence,individual clones may persist for very long periods, possiblyhundreds of years. A computer model of rhizome growth was used to postulate theextent of intermixing of old clones. It indicated that old clonesbecome very fragmentary and totally inmixed with their neighbours,one ‘clump’ often representing several clones. To supplement the model, plants from a woodland with an unbrokencarpet of Anemone nemorosa were collected, 27 morphologicalcharacters measured and the data analysed using principal componentsanalysis and cluster analysis. These supported the hypothesisthat old clones are large and fragmentary with complete intermixing. The possible role of soil factors in influencing rhizome extensionis discussed and the strategy of A.nemorosa is compared withthose of its close associates in the pre-vernal woodland herblayer. Anemone nemorosa L., wood anemone, rhizome growth, clone development, computer model, vegetative reproduction     

A mangrove community in the New Hebrides, south-west Pacific

A general survey of the mangal at Port Stanley, Malekula, New Hebrides, the most extensive mangal in the archipelago, was conducted over an 11-day period in September/October 1971. Seventeen species of true mangrove tree and mangrove associates were recorded. As is characteristic of mangal, this flora was distributed in a zonal pattern, four zones being recognized. Certain anomalies in zonation were attributed to a recent episode of crustal uplift. The aquatic component of the fauna was dominated by molluscs (26 species) and Crustacea (20 species). The terrestrial vertebrate fauna consisted of 4 species of reptiles, 21 birds and 5 mammals.
The mangrove community at Port Stanley is an integral part of that of the Indo-West Pacific region. However it is much restricted in number of species, and reasons for this are suggested: distance from Malesia, lack of fresh water, and shallow soils with little silt deposition. Faunal impoverishment is clearly associated with floral impoverishment.     

Observations on “Detubulated” Muscle Fibres

GLYCEROL treatment of striated muscle^1–3 has been widely assumed to be a means of disconnecting the transverse tubular system from the surface membrane. Exposure of a sartorius muscle to Ringer plus 400 mM glycerol followed by a return to Ringer, reduces the membrane capacity of superficial fibres and the muscle is mechanically inactive even though the fibres can transmit action potentials; both these effects might be expected if the transverse tubular system was destroyed or disconnected from the extracellular fluid. We have studied this mechanical decoupling on isolated muscle fibres from the semitendinosus, examining the effects of glycerol concentration. Our results suggest that decoupling may be a complex process and in particular they show that under some circumstances both the depolarization and the loss of the twitch can be reversed by re-exposure to glycerol.