Rela tive Million Du ration Era Per iod years of Eros Epoch ago QUATERNARY RECENT- •t>ou' 10,ooo ~ · · • PLEISTOCEN E · 1 - 2 ,..;u<ony• ••• r----------------f--------------------~1 -2 TERTIARY <JbOul G) molo.on ye a •• CRETACEOUS ot:.....,, 70 my (.) r----------- ------------lc.135 0 JURASSIC N "boul 55 mv 0 (/) UJ TRIASSIC ~ a bOul 35m v PERMIAN a boul 5 5 my r---------------------------------------lc.280 CARBONIFEROUS <lbo.. l Ei5 nov Molford 5d FIOROLANO NAT IONAl • Polmer)IOn () PARK Ounedon Portobello DEVONIAN Du•ky Sd ~l AN D llLlOut so'" y FQ\tf..q~g ·ll 1-----------------------lc.395 S•eworT h r2_ sf .. SILURIAN r;.._;J ,-All aboul 4 5 mv 3.000 1----------------------------------------l <.440 m y ORDOVICIAN about 60 m y (.) r---------------------~ <.~0 2 CAMBRIAN 0 ObOUI 70 m y UJ <(_. ~ !.J! Aud lond h . PRECAMBRIAN 4 ,COO my. Q c.ompbell h . Oldest-known earth rocks - about 3,600 m.y. more than 4.500 million years ago The isolation of New Zealand, illu strated by showing a hemisphere with the Sout h Pole situated on Wel lington (see art icle, page 358). AUSTRAliAN NATURAl HISTORY JUNE 1976 VOLUME 18 NUMBER 10 PUBLISHED QUARTERLY BY THE AUSTRALIAN MUSEUM. 6-8 COLLEGE STREET, SYDNEY PRESIDENT, MICHAEL PITMAN ACTING Dl RECTOR, DESMOND GRIFFIN GONDWANA GENESIS 346 BY C.A. FLEMING THE SHAKY ISLES 350 BY R.H. CLARK FROM HAWAIKI TO TE-IKA-A-MAUI 354 BY JANET DAVIDSON FOREST IN ISOLATION 358 BY BRUCE HAMLIN ARCHAIC ELEMENTS AND A HOST OF IMMIGRANTS 362 BY IAN G. CROOK IN THE FLIGHTLESS TRADITION 366 BY G.R. WILLIAMS AN IMPORTED FAUNA 370 BY M.J. DANIEL A HAPHAZARD INSECT ASSEMBLAGE 374 BY GEORGE W. GIBBS COVER: Ferns, mosses and lichens, softening the outlines and adding to the variety. ISLANDS. OCEANS AND MARINE LIFE PATTERNS 376 (Photo: Diane Brown) BY ALAN BAKER AND JOHN YALDWYN Annual Subscription : $4.50- Australia; $A5- Papua New Guinea; $A6-other EDITOR/ D ESI G NER countries. Single copies: $1 ($1.40 posted Australia) ; $A 1 .45-Papua New NA NCY SMITH Guinea; $A 1.70-other countries. Cheque or money order payable to The: A SSISTANT EDITOR ROBERT STEWART Australian Museum should be sent to The Secretary , The Austral ian Museum, P R O DUCTI O N ASSISTANT PO Box A285, Sydney South 2001 . Overseas subscribers please note that LEA H RYAN monies must be paid in Australian currency. C I RCULATION ROY HELM New Zealand Annual Subscription: $NZ6.25. Cheque or money order payable EDI T ORIAL COMMITTEE to the Government Printer should be sent to the New Zealand Government HAROLD COGGER Printer, Private Bag, Wellington. KINGSLEY GREGG PA TRICIA McDONALD Opinions expressed by the authors are their own and do not necessarily represent RONALD.STRAHAN the policies or views of The Australian Museum . 345 •A£ C0M'-'[ N Q[0 A[ TAll P R ICf INT E~NA T I QN..._L ST ANOAAO S£AoAL NVM~( A 000<11 911"0 fairly close until after early flowering plants such as the Southern Beech (Nothofagus) dispersed. Africa, a not­ able exception, had drifted apart too early to receive this group of trees, which botanists maintain cannot cross ocean barriers. It did, however, receive the Proteacea. Many of the plants and animals originally common to Australia, New Zealand and South America probably dispersed at this time, including many inver­ tebrates, such as those of the forest-floor litter. After New Zealand became isolated from other la nds, its geographic outline and its coastline changed considerably as the sea transgressed its outly ing parts. Sea flooded the ri ses and plateaux extending north­ westward toward Lord Howe and Norfolk Islands and eastward to the Chatham Islands and also the Campbell Blow Holes and he lofty islands of New Zealand rise from a system Plateau, which extends southeastward to the subantarc­ Pancake rocks at Punakaiki on the T of shallow submarine rises and plateaux between tic Auckland and Campbe ll Islands. Most of these west coast of the the Tasman Sea and the deep Pacific, forming part of islands, however, rose much later as volcanoes that South Island. the unstable seismic and volcanic belt which circum­ built up above sea level. The coastline of the New scribes the Pacific. Rapid geological changes in these Zealand archipelago constantly changed so that its areas have long intrigued the earth-scientist. Most geography was unstable. After the uplifting of moun­ geologists now believe that New Zealand was once a t ains during the Mesozoic e ra the land was gradually ma.rginal fragment of the vast southern continent worn down; chemical weathering was widespread and Gondwanaland, broken off by sea-floor spreading when the marine transgression reached its maximum in which developed a new ocean crust and in turn formed t he Oligocene, the islands were reduced to quite small the South Atlantic and Indian Oceans, the Tasman Sea areas of low relief w it h deeply weathered soils, flanked and finally the segment of Southern Ocean south of by sedime nts composed of quartz pebbles and sand. Australia. This may have bee n a critical period for many plants A trough filled with Permian and Jurassic sediments, and animals but most of the Eoce ne flora seems to lying off the Pacific coast of Gondwanaland, was have survived. If , on the other hand, New Zealand had twisted a nd ruptured in the late Mesozoic, just before been colonised by lu ngfishes and monotremes or even the Tasman Sea developed, widening t o sunder New ma rsupials before achieving full iso lation, they may Zealand from East Australia and Antarctica. The sedi­ have become extinct during this period. ments in the trough hardened to form the ~andstone If 'sweepstakes extinction' of part of New Zealand's fragments of greywackes of New Zealand's main moun­ Gondwana heritage is speculative in the absence of t ain ranges. Together with part of Gondwanaland, they fossil evid ence, there is no d oubt that New Zealand, formed a land much larger than the New Zealand of despite increasing isolation, continued to receive a t oday. 'sweepstakes colonisation' of plants and animals across New Zealand seems to have once shared with its the sea from outside her borders. The fossil record does neighbours common gro ups of plants and animals like give evide nce of the first appearance, credibly by the conifers Araucaria and Agathis and podocarps of colonisation, of plants (from their pollen grains in several generic groups, the tuatara, the sole survivor dated sediments), shallow-water marine invertebrates of a most ancient order of reptiles, primitive frogs, (from their fossi l she lls and skeletons). and marine Ratite birds (ancestors of the emus, moas and kiwis) vertebrates (whales, penguins) but there is no significant and perhaps also lungfishes and monotremes. Most fossil record of land animals. To judge by the fossils fragments of Gondwanaland seem to have remained present, sea tempe ratures and land climates varied CHARLES FLEMING, is Chief Paleontologist at the New Zealand Geological Survey, DSIR. A prominent naturalist, he has written many papers on topics such as molluscs, ecology, oceanography, cicadas, fossil crabs, penguins, barna-cles, conservation and historical biogeography. 346 AUSTRALIAN NAT URAL HISTORY GONDWANA GENESIS BY C.A. FLEMING appreciably during the Cenozoic, becoming subtropical, two groups, especially in the absence of a well docu­ or even marginally tropical, during the Upper Eocene mented fossil record. Some of the plants that achieved and in the Lower Miocene. Afterwards a cooling but a partial circumpolar distribution by reaching both fluctuating trend led to the Quaternary-a sequence sides of the Pacific may have been of Malayo-Pacific of about six cold glacial ages alternating with temper­ origin, having extended south to points of entry into ate interglacial ages from 1.8 million years ago unti I the West Wind Drift in Australia or New Zealand, the present day. leaving a diminishing trail of species as they spread Colonists can be grouped in terms of their apparent downwind to the east. Fossil pollens suggest that source area into Australian, Malayo-Pacific, Austral Coriaria (tutu) and Aristotelia entered New Zealand (or 'Antarctic') Holarctic (north temperate) elements. in the early Miocene. A steady trickle of Australian molluscs, crabs, and The rate of Malayo-Pacific immigration fell off in plants continued to establish themselves in New the late Miocene and Pliocene and many earlier colon­ Zealand, some destined to remain, like the rock oyster ists requiring subtropical climate failed to survive the (Saccostrea) and the teatree (Leptospermum); others Quaternary Ice Ages, among them the reef corals, such as the Casuarina became extinct. The Malayo­ many molluscs, coconuts, most of t he Proteacea, some Pacific region became the major source of plants and crabs, the 'brassi' group of Nothofaqus (which survive animals colonizing New Zealand during the mid-Tertiary, on the mountains of New Guinea, New Britain and when temperatures were warmest so that reef-corals, New Caledonia). and Casuarina. A recent discovery shelled protozoa ferns, mangroves, coconuts, cone shows that Acacia briefly colonised New Zealand at shells and nautiloids joined other plants and seashore the end of the Pliocene but did not survive long, animals of tropical origin. although another young Australian colonist, the pro­ After the Cretaceous, the Austral e lements that con­ teaceous Persoonia, survived in the Recent flora. tinued to arrive were probably all dispersed across the Toward the end of the Tertiary, mountain-building sea with the help of the West Wind Drift. They include movements quickened New Zealand's mobile belt. seals, seabirds, fish and shellfish, and plants that are at Volcanoes had erupted at intervals both on the sea­ least partly circumpolar, such as the Kowhai (Sophora) floor and on land throughout geological history, but and Ranunculus acaulis.