Tuatara: Volume 9, Issue 1, September 1961
New Zealand Biotic Provinces
New Zealand Biotic Provinces
If all organisms were pelagic their distributional patterns would more or less correlate with the physical factors of water, temperature, ocean currents, and prevailing winds.
However, the fact that many organisms lack or have poorly-developed free-swimming larvae introduces a percedure of stenozonal species or sub-species, and the presence of these to a marked degree gives rise to the necessity of subdividing regiob or sub-regions into provinces.
A past or present topographic barrier often service as a segregating influence but such barriers are not essential, for more distance is often sufficient to outrange the distributing powers of many stenozonal page 2 organisms. This is well instanced in the case of the North American West Coast, where three somewhat overlapping provinces are apparent.
A province may be defined as an area within a faunal region that exhibits a marked percentage of endemism.
Published proposals for the subdivision of the Maorian Sub-region are as follows:
All the provinces so far nominated for New Zealand apply to the intertidal zones plus the shelf. The pelagic elements have been noted, but more or less as influences only.
When faunas from the deeper waters are better known it will almost certainly be found that provinces are fewer, more extensive, and bear little or no resemblance to the inshore ones.
We may therefore have to consider the problem as three-dimensional, i.e., (1) broad oceanic areas for pelagic faunas; (2) inshore and shelf faunas; (3) deep sea faunas (probably divisible into several levels).
|The Kermadec Province||—||Kermadec Islands|
|The Cookian Province||—||North Island of New Zealand|
|The Forsterian Province||—||South and Stewart Islands|
|The Moriorian Province||—||Chatham Islands|
|The Rossian Province||—||Subantarctic Islands, including Macquarie Island|
In 1926 (Trans. Roy. Soc.) Finlay added the proviso that the Cookian and Forsterian may not be natural as previously defined and suggested that in the event of readjustments these names apply to the southern portion respectively of each island.
|Aupourian:||Northland Peninsula and Three Kings Islands from above Ahipara on the west coast and Whangaroa on the east coast.|
|Cookian:||Rest of the North Island and the northern part of the South Island down to Westport on the west coast and Banks' Peninsula on the east coast.|
|Forsterian:||Otago and Stewart Island.|
In 1940 (Trans. Roy. Soc. N.Z.) I adhered to my previous definition of the Aupourian and stressed the strong representation of the Peronian, that is the New South Wales element, in the fauna.
Aupourian: Within the Subtropical Zone of surface water.
Cookian: Mixed waters of middle region of New Zealand.
Moriorian: Isolation and mixed waters.
Forsterian: Isolation plus predominant Subantarctic waters.
Rossian: Entirely within the Subantarctic Zone of surface waters, plus isolation.
In 1951 (Discovery Reports, Vol. 26, p. 67) I advocated dropping the name Rossian Province and substituting a prior name of Waite, 1916, the Antipodean (i.e. Antipodes District) for the Subantarctic Islands of New Zealand, including Macquarie Island, Stewart Island and Southern Otago.
In 1949 (Report of the Sixth Science Congress, Royal Society of New Zealand, Vol. 76. part 5) Miss L. B. Moore summarised the propositions of Cockayne, 1928; Powell, 1936; and Fleming, 1942; in The Marine Algal Provinces of New Zealand, Miss Moore remarked that “It is not yet clear whether the equivalent of Powell's Aupourian Province can be recognised for the marine algae, but if so it would extend at least as far as Bay of Islands and Poor Knights, and would then include some 14 species not otherwise known on the New Zealand mainland.'
In 1952 (N.Z. Geological Survey Pal. Bulletin 18, p. 16) Mr. N. de B. Hornibrook in monographing New Zealand Tertiary and Recent Marine Ostracoda quotes me (correspondence) as follows: “I have recently gathered good evidence for extending the Aupourian to as far as East Cape, but on the West Coast it does not seem to reach below Ahipara.’
Forsterian: Snares Island, Stewart Island and Otago.
Antipodean: Antipodes, Bounty, Auckland and Campbell Islands.
Kerguelenian: Macquarie Island, Kerguelen, Heard Island, Marion Island, Prince Edward Island and Crozets.
Since this was written, Fleming (1951) published a bathymetric chart of the area which is in harmony with the above independently-reached conclusions. I note that Fell also (1953) in his Echinoderms from the Subantarctic Islands of New Zealand separates the Snares fauna from that of the other southern islands, and places it in the Forsterian.
I note also that Dell in the N.Z. Oceanographic Committee's O.R. 82 reports the finding of many species of mollusca previously recorded only from off the Snares Islands, in the Chatham Islands expedition Station 34, from 130 fathoms east of the Chathams. This is relevant to my forecast that provinces may be fewer and more extensive in the deeper waters. Before treating the New Zealand page 4 provinces in some detail I should state that the Kermadec Province has been omitted, since most writers consider that this province does not truly belong to the Maorian sub-region.
Dr. Dell contributed an excellent paper on the molluscan fauna of this province to the Eighth Pacific Science Congress (not yet published) in which he considered the Kermadec fauna to be an outlying sub-region of the Indo-West Pacific of equal value to the Philippian for Lord Howe Island and the Montrouzierian for New Caledonia.
This province is characterised by a large percentage of Peronian organisms which have obviously reached here through the agency of the East Australian or Notonectian warm water current and subtropical or approaching subtropical conditions have enabled them to stay.
The molluscs include several species of the Cymatiidae, Agnewia tritoniformis, Xenogalea pyrum and labiatum, Tolema and Emozamia. The echinoids are represented by the fire-brick starfish Asterodiscus and the crustacea by the frog crab Lyreidus. Some of the exotic genera that have reached here by means of the Notomectian current have since developed as local sub-species.
After ignoring the relatively constant influx of Peronian and other wide-ranging species, some of the characteristic elements of the Aupourian are:
The carrier shell, Xenophora neozelancia, Tonna haurakiensis, Pteronotus eos, Gomphina maorum, Alcithoe depressa, Venericardia reinga, Haliotis virginea crispata, the large heart-urchin, Brissus gigas, and the brachiopod, Terebratella haurakiensis.
Evidence of the former cold phase in the Aupourian is exhibited by the presence of the Subantarctic bivalve molluscan genera Gaimardia, Kidderia and Costokidderia. The presence of the giant kelp, d'Urvillea, the Cookian limpet, Cellana denticulata, and a record of the Forsterian Cymatid mollusca, Fusitriton laudandum, may be related to prevailing south-west wind and the upwelling cold water on the west coast under present conditions.
It should be pointed out also that the configuration of the Northland west coast results in the prevailing south-west wind operating on-shore in the north but off-shore in the south.
It is worthy of note in regard to the extra limital distribution of Cellana denticulata that its northern occurrences are invariably on off-shore islands or on strongly projecting land features. It suggests that point-to-point distances may be achieved within the time factor in situations where strong tidal currents operate, but that the larval free-swimming period is not sufficiently long to enable a more thorough dispersal into the embayed sections of the coastline.page 5
A review of the evidence now suggests more positive boundaries for the Aupourian. All interests seem to be in agreement that the eastern boundary should be the East Cape. The western boundary is not so clearly indicated, due to the conflicting effects of the Notonectian warm water current, upwelling cold water and prevailing south-west winds, but a division of some elasticity is indicated as occurring between Reef Point, Ahipara and Manukau Heads.
Recent records of Zeacolpus ahiparana from Manukau Heads and Tonna haurakiensis from off Maunganui Bluff support this contention.
The Cookian as pointed out by Fleming (1944) occupies the middle region and is largely in a belt of mixed waters with both subtropical and subantarctic influences.
The northern boundaries seem reasonable in relation to those fixed for the southern boundary of the Aupourian. The southern boundaries for the Cookian can be conveniently fixed as far as the littoral is concerned by the buffer zones represented by long shingle beaches on each coast, with impoverished fauna that separate the Cookian from the Forsterian. That these boundaries do not apply so rigidly for the shelf fauna is clearly shown by occurrences of warm water genera trawled both off Timaru and off Greymouth. The species instanced are Galeodea triganceae recently described by Dr. Dell and the northern Ranella multinodosa.
The Cookian as at present constituted is complicated by the assumed comparatively recent formation of Cook Strait and the evidence of a middle Pliocene division between the islands, approximately between Wanganui and Napier.
Some of the characteristic Cookian stenozonals are Verconella ormesi, Cellana denticulata, Thoristella chathamensis cookiana and Buccinulum colensoi. which ranges from the Wellington east coast to East Cape.
The Forsterian is a well defined province including the whole of Otago and Stewart Island. I have in my report on the Cape Expedition extended the province to take in the Snares Islands, which are situated on the South Island shelf. The molluscan fauna of the Snares is clearly Forsterian rather than Antipodean (= Rossian).
It is worthy of note that Dr. Fell in his latest paper (1953). Echinoderms from the Subantarctic Islands of New Zealand, also considers the Snares fauna to be essentially Forsterian.
The most characteristic species of the Forsterian is the limpet Cellana redimiculum. The subantarctic influence is, as would be expected, more marked than in the Cookian. The genera involved are Gaimardia, Kidderia, Costokidderia, Margarella and Kerguelenella.page 6
The occurrence in the estuarine waters of the Manukau Harbour of a mollusc simulating if not identical with the common Forsterian coast Maurea punctulata stewartiana is puzzling. Since the stations are different one explanation is that the Manukau occurrence merely represents an ecological variation of the common northern typical species.
However, another possibility occurs to me after hearing a paper by Drs. Habe, Kuroda and Miyadi at the Eighth Pacific Science Congress, entitled Some Problems on Marine Biogeographical Micro-Provinces surrounding Japan. These authors point out that in southern Japan cold water continental coastal fauna elements often survive in harbours, whereas the adjacent open coast may have a warm water fauna belonging to a different marine province.
The Manukau Maurea may therefore be a relic from a past colder climatic phase when the Forsterian elements would presumably have extended much further north.
We have such evidence in the Nukumaruan North Island occurrences of the scallop Chlamys delicatulus, which at present does not seem to occur alive north of Otago Peninsula.
A recent finding of two examples of the brachiopod Neothyris lenticularis in 80 fathoms off East Cape may represent another survival of an at present otherwise restricted Forsterian element.
The percentage of species or sub-species restricted to the Forsterian is quite considerable.
This is the name which I contend should replace Finlay's Rossian from which I exclude the Snares as already mentioned, and also Macquarie Island, which I place in the Kerguelenian.
This province lies entirely within the Subantarctic Zone of surface waters. The fauna is an impoverished one, including only the most tolerant of the mainland genera with a liberal sprinkling of the characteristic subantarctic genera: Patinigera, Pareuthria, Margarella, Kerguelenella and Plaxiphora
Endemism is high with both elements in the fauna.
In my report on the Cape Mollusca I advocate segregating Macquarie Island from the Antipodean on the evidence of the inclusion in the fauna of a number of stenozonal truly subantarctic genera that do not occur in the other New Zealand subantarctic islands, i.e. Falsilunatia, Puncturella typical, Trophon typical, Prosipho, Admete, and Lima pygmaea.
That Macquarie Island was formerly more closely linked with the New Zealand shelf is indicated by the presence of Tawera, Chlamys page 7 delicatulus, a Maurea of the spectabile group, Plumbelenchus, and the limpets Notoacmea pileopsis sturnus, and Actinoleuca
The presence of the genus Cymatona, known elsewhere only from the East Australian Continental shelf is a surprise element in the Macquarie fauna.
The Moriorian was nominated for the Chatham Islands fauna, which has a considerable percentage of endemic sub-species and shows strong northern and southern influences in almost equal amounts, as one would expect from the situation of the group.
|1 — Aupourian||665||4 — Moriorian||260|
|2 — Cookian||602||5 — Antipodean||225|
|3 — Forsterian||444||6 — Kerguelenian|
(Macquarie Id. only)
Since the above was written Dr. Dell (1960, Biological Results of the Chatham Islands 1954 Expedition. Part 4, D.S.I.R. Bull. 139 (4) has evaluated the Moriorian Fauna in the light of the very considerable recent additions he has made to the fauna (see also Dell, 1956. The Archibenthal Mollusea of New Zealand, Domin. Mus. Bull. No. 18).
The result of Dr. Dell's survey emphasises the distinctive character of the Moriorian but arrives at more precise conclusions regarding the relationship of the fauna in respect to mainland provinces. He gives a total of 320 species, of which 204 occur also in the Cook Strait area, 6 are pelagic and 49 are endemic. Only 13 are confined elsewhere in the north while 38 occur in the south with 5 in the subantarctic islands.
The Moriorian remains well defined not only by the high percentage of endemic species (15.3%) but also by the number of common widespread mainland species that are not represented — i.e. Mytilus canaliculus, Mactra discors, Spisula aequilateralis, Dosinia anus, lambata and subrosea, Dosinula, Notocallista, Myadora striata, Scutus, Lunella smaragda, Struthiolaria, Baryspira, Alcithoe, Benhamina and a number of others.
Those interested in antarctic marine faunas are referred to a recently published paper (Powell, 1960, Antarctic and Subantarctic Mollusca, Rec. Auck. Inst. Mus., Vol. 5 (3-4), pp. 117-93).
The faunal characteristics of the antarctic and subantarctic areas, as well as the physical factors involved, of ocean currents, antarctic and subtropical convergences, effects of upwelling cold water, submarine ridges and deep-water basins are all discussed.page 8
That faunal divisions based upon shallow-water faunas do not necessarily apply to the Archibenthal and deeper waters is evidenced by some previously considered anomalous distributional patterns.
For instance it is shown in the case of Pontiothauma, a genus of Turrids known from Bay of Bengal, off Java and Enderby Land, Antarctica, in deep water, that they follow the northward flowing antarctic cold heavy water along the bed of the deep ocean basins and the same applies regarding the arctic-antarctic continuity of another Turrid genus, Aforia, which goes deep over the tropical zone and is otherwise assisted in its temperature requirements by upwelling along its west American distributional route.
During a recent (May, 1961) dredging expedition (Govt. Research Trawler “Ikatere’) along the shelf of the Northland east coast several molluscs were obtained at 150-240 fathoms that were previously known only from the Archibenthal of eastern Otago. i.e. Parvamussium maoria Dell. 1956.
Dell, R. K., 1960. Biological Results of the Chatham Islands 1954 Expedition, 4. D.S.I.R. Bull. 139 (4).
Fell, H. B., 1953. Echinoderms from the Subantarctic Islands of New Zealand. Rec. Dom. Mus., 2: 73-111.
Fleming, C. A., 1944. Molluscan Evidence of Pliocene Climatic Change in New Zealand Environments. Trans. Roy. Soc. N.Z. 74: 207.
—— 1951. Some post-Miocene Changes in New Zealand Environments. N.Z. Science Review, 9; 166-71.
Finlay, H. J., 1925. Some Modern Conceptions applied to the Study of The Cainozoic Mollusca of New Zealand. Verbeek Mem. Birthday Vol.; 161-72.
—— 1926. A further Commentary on New Zealand Molluscan Systematics. Trans. N.Z. Inst. 57: 320-485.
Hornibrook, N. de B., 1952. Tertiary and Marine Ostrocoda of New Zealand. N.Z. Geol. Surv. Pal. Bull. 18.
Moore, L. B., 1949. The Marine Algal Provinces of New Zealand. Trans. Roy. Soc. N.Z 77: 187-9
Powell, A. W. B., 1937. New Species of Marine Mollusca from N.Z. Discovery Reports 15; 153-222.
—— 1940. The Marine Mollusca of the Aupourian Province, New Zealand. Trans. Roy. Soc. N.Z., 70; 205.
—— 1951. Antarctic and Subantarctic Mollusca. Discovery Reports 26; 49-196.
Waite, E. R., 1916. The Fishes. Sci. Rep. Aust. Antarct. Exped., 1911-1914, 3; 8.