Abstract

For the first time, geological and palaeontological evidence is presented that makes the presence in New Zealand of a marsupial just possible and that of a platypus-like monotreme possible and likely. The latter alternative is preferable, so that the waitoreki a non-descript supposedly mammalian animal of New Zealand, could be an analogue of the Australian Duck-billed Platypus (Ornithorhynchus anatinus), perhaps even more ancient than the platypus.

Key note:Chronectes minimus, fossil monotreme, New Zealand otter, platypus, Steropodon galmani, Yapok.

Dedication

Dedicated to Dr phil.habil., Dr. med. INGO KRUMBIEGEL (Hamelin, Germany), Nestor of Cryptozoology, on the occasion of his 85th birthday, 26th February, 1988.

Observations and Discussion

It is generally understood, particularly in New Zealand, that at least some of the 19th century sightings of the mysterious otter-like waitoreki refer to the Australian Opossum or Phalanger (Trichosurus vulpecula), which was first liberated at Riverton, Southland, in 1858 “with the idea of starting a skin trade’ (McLintock, 1966). However, earlier reports, and the waitoreki's reported aquatic way of life, as well as its Maori names waitoreki and kaurehe point to the existence of a different animal, which must have reached and colonized the area of present-day New Zealand prior to its becoming islands in the course of the Cretaceous. This would rule out all mammals. Placentalia in particular are known to have diversified later in geological time. Likewise, neither monotremes nor marsupials are considered to have reached Australia when New Zealand was still part of that landmass. The limited aquatic ability of mammals in general and monotremes and marsupials in particular should have prevented trans-oceanic dispersal. As Watson (1960) aptly summarized the communis opinio, “The extreme improbability of this has caused most New Zealand biologists to dismiss all the reports [on the waitoreki] as illusory’. However, recent findings have changed the premises of this assumption, and the intriguing possibility has arisen that a monotreme or marsupial might in fact have reached early pre-New Zealand. In order to decide the question whether the waitoreki might thus actually constitute a mammal unknown to science, it is a necessary prerequisite to disentangle the palaeobiogeography of marsupials and monotremes.

Marsupials are usually considered as having originated in South America. Biogeographers at first favoured dispersal route, with the early marsupials travelling from the Americas across Asia to Australia. Recently the first fossil marsupial from Asia has been reported from central-Asiatic U.S.S.R. (Benton, 1985). A southern dispersal route, from South America to Australia via Antarctica, was preferred by others influence by Wegener's theory of continential drift. The immigration, however, presumably took place too late in geological time to involve New Zealand, which had already drifted apart from Australia. By the end of the Cretaceous period, about 70 million years ago, connections with large land masses beyond New Zealand ceased to exist. This is the “official” explanation one will page 63 encounter when asking “Why are there no mammals (bats excepted) indigenous to New Zealand?’ There is the above mentioned prerequisite for this explanation: the assumption that neither marsupials nor monotremes were able to survive or to stay alfoat on a natural vegetable raft, to say nothing of actively swimming. However, there is one recent genus of Marsupialia with one species (in Cretaceous times there should have been others) that has adopted an aquatic way of life, namely the otter-like Water Opposum or Yapok (Chronectes minimus). It ranges today from S. Mexico to Brazil and NE Argentina, and frequents fresh-water streams and lakes; in some areas it is found “at considerable altitudes’ (Walker, 1964). Head-+-body length is c. 30cm, with an additional length of tail of c. 37.5cm. The dense pelage is pearl-grey with a pattern of blackish bands on the back; chin, chest and belly are creamy white. The tail is rat-like, furred only at the base. The hind feet are webbed. Yapoks are the only aquatic marsupials and are excellent swimmers and divers. They prey on crayfish, fresh-water shrimp and fish, with probably some additional plant material (Walker, 1964). Yapoks are nocturnal, they spend the daytime in subterranean dens tunnelled into river banks, with an exit just above the water-line and a tunnel diameter of c. 15cm. These animals will certainly not hesitate to enter any kind of vegetable “raft” afloat in a jungle bayou, and become involuntarily seaborne (by this method yapoks might have reached the island of Trinidad where they are said to occur. Cf. Walker, 1964). An early precursor of Chironectes might have crossed the gap between Australia-Antarctica and pre-New Zealand by means of a natural “raft”, thus braving a shallow sea of scattered islands and tidal reefs with the help of palaeo-winds and palaeo-currents during a few days' voyage. Six years ago. a South American marsupial (a polydolopid) was found in Eocene deposits (about 40 Myr ago) of Antarctica (Woodburne & Zinsmeister, 1982), a find that suggests a similar “braving of open sea” between the southermost tip of South America and an ice-free Antarctica (situated in more northerly latitudes than today).

Should the southern dispersal route to New Zealand prove valid (at least for animals with aquatic adaptations), the waitoreki might turn out to be akin to the yapok, and it should be worthwhile to have a closer look at the yapok's natural history and ecology in order to determine those of the waitoreki.

On the other hand, new evidence suggests that the waitoreki may rather be a monotreme. Recently (1985), Australia's first fossil Mesozoic mammal, a platypus-like monotreme, was described (Archer et al., 1985). It was discovereed in early Cretaceous sediments in New South Wales and was named Steropodon galmani (n.gen. and sp.). The fossil find represents an early ornithorhynchid-like (platypus-like) monotreme of rather large size. The fact that distinctive badger-sized monotremes were present in Australia in the early Cretaceous (when New Zealand was presumably still part of that landmass) indicates not only an antiquity of this group hitherto unheard of and certainly great enough to have settled New Zealand without having to brave an open sea, but also testifies to an evolutionary trend which obviously favoured this group of Monotremata. For contemporaneous dinosaurs of the same local fauna include very small forms (hysilophodontid dinosaurs) which were probably not at all larger than the sympatric monotremes.

Should this theory hold true, the waitoreki might eventually prove to be a New Zealand analogue of the Australian platypus. Its natural history and ecology will perhaps be found to be similar to those of the Duck-billed Platypus (Ornithorhynchus anatinus). The modern platypus has a head-body length of 30-45cm, with an additional tail length of 10-15cm. The flat tail is shaped like a beaver's although completely furred. The colour of the fur is deep amber or dark brown on the back, the belly is white to yellowish chestnut. They feed on crayfish, shrimp, snails, worms, tadpoles, insect larvae and small fish, which they gather from the bottom of page 64 streams and ponds. As has been reported of the waitoreki, adult platypus males have “a musky, “almost fox-like” odor which is emitted from scent glands on the undersurface of the base of the neck' (Walker, 1964). As the modern platypus is known to hibernate for periods of a few days during the winter, a platypus-like animal might be predisposed to withstand cold. The waitoreki probably developed an even greater cold resistance as it must necessarily have survived the climatic deterioration of New Zealand associated with the latest phase of extended glaciation in South Island, which correlates with the last period of major extension of Northern Hemisphere ice sheets (Nelson et al., 1985). Of course, the waitoreki does not build dams, nor does it construct “houses like bee-hives’ (Taylor, 1855). This statement should be considered a wilful mystification on the part of a witness who admittedly had never seen a waitoreki and might therefore have tried to improve on his “meagre” knowledge. Rather, the waitoreki might live in burrows like those which the platypus is known to construct in banks along streams and ponds and which, contrary to those of the yapok, open below water level. Platypus burrows with holes opening below water-level are found in the Australian Alps, whereas on the plains, burrows are said to open mostly above water-level. Similarly, a hole below water-level was reported for the waitoreki. In c. 1918 an eye-witness saw an animal swimming in Waikiwi Creek, Grassmere (not far from Invercargill) “and later saw a hole like a rabbit-hole below the water-level not far away’ (Wall, 1926). Further, the waitoreki will possibly be found to have four webbed feet as the platypus has. Correspondingly, the waitoreki might possess a small bill (similar to that of the platypus) hidden in the fur and thus hardly discernible from some distance. An animal evolutionarily perhaps even more “old-fashioned” than the platypus, the waitoreki might feature well-developed teeth, the dental formula including three molars, the number evidently present in young Ornithorhynchus anatinus (which is the only known monotreme to retain even vestigial teeth). Lastly, the waitoreki might be found to lay eggs as the playtpus does, and nourish its young in the same way. In 1848, when Walter Mantell was travelling through coastal Canterbury and Otago on South Island, he passed on the following report: “Maopo, headman at Te Taumutu, states that the Kaurehe lays eggs as large as those of a duck!!’ (Mantell, 1851).

As there is now fossil evidence for a flourishing platypus-like group in Australia which pre-dates the separation of New Zealand, the second alternative, i.e. the waitoreki a platypus-like monotreme, seems at present to have the highest degree of probability, should the waitoreki actually constitute a mammal unknown to science. Therefore the mysterious animal might, as Charles Darwin (1888) put it, “turn out something like the solenhofen bird’, i.e. the Archaeopteryx from Jurassic limestone quarries near Solenhofen, Bavaria, Germany. As Alfred Wallace wrote on the waitoreki, “it is to be hoped that this creature will not be allowed to become extinct without a determined effort being made to secure specimens in order to study its structure and its relationship to other animals’ Wallace, 1888). Due to the indifference of most New Zealand scientists, past and present, it could well be too late now.

Acknowledgements

The author thanks Mrs Josie Laing, Canterbury Museum, Christchurch, New Zealand, and Ms. Christine Tuitubou, National Library of New Zealand, Wellington, for their kind help in providing reference material.

References

Archer, M., Flannery, T.F., Ritchie, A., and Molnar, R.E. 1985. First Mesozoic mammal from Australia - an early Cretaceous monotreme. Nature 318: 363-366 (+ cover).

Benton, M.J. 1985. First marsupial from Asia. Nature 318: 313 (quoting the original Russian description: Gabunia, L.K. & Shevyreva, N.S., Doklady Akad. Nauk. S.S.S.R. 281 (1985): 684).

Darwin, F. 1888. The Life and Letters of Charles Darwin. London, 3 vols.

McLintock, A.H. (Ed.) 1966. An Encyclopaedia of New Zealand. Wellington: NZ Government Printer, 3 vols.

Mantell, G.A. 1851. Petrifactions and their Teachings; or a Handbook to the Gallery of Organic Remains of the British Museum (spine-title Mantell's Fossils of the British Museum). London: British Museum (National History).

Nelson, C.S., Hendy, C.H., Jarrett, G.R., and Cuthberton, A.M. 1985. Near-sychroneity of New Zealand alpine glaciations and Northern Hemnisphere continental glaciations during the past 750 kyr. Nature 318: 361-363.

Taylor, R. 1855. TE IKA A MAUI, or, New Zealand and its inhabitants, illustrating the origin, manners, customs, mythology, religion, rites, songs, proverbs, fables, and language of the natives. Together with the geology, natural history, productions, and climate of the country; its state as regards Christianity; sketches of the Principal Chiefs, and their present position; with a map, and numerous illustrations. London: Wertheim & MacIntosh.

Walker, E.P. (Ed.) 1964. Mammals of the World. Baltimore: The John Hopkins Press, 3 vols.

Wall, A. 1926. The Mythic Otter of New Zealand. The Press (Christchurch, N.Z. 8th Sept., 1926).

Wallace, A.R. (Ed.) 1888. Australasia. 5th ed. London: Stanford.

Watson. J.S. 1960. The New Zealand “Otter’. Records of the Canterbury Museum 7: 175-183.

Woodburne. M.O., and Zinsmeister, W.J. 1982. Fossil land mammal from Antarctic. Science 218: 284-287.

Additional references from the publications of ISC Honorary Member Dr. phil. habil, Dr. med. Ingo Krumbiegel, to whom this article is dedicated.

Krumbiegel on the yapok: 1940. Die Saugetiere der Sudamerika-Expedition Prof. Dr. Kriegs, 5. Schwimmbeutler. Zoologischer Anzeiger, 132, 3/4: 63-72.

1949. Unerfullte Wunsche aller Zoobesucher. Arche Noah, 1, 3: 44-45.

1949 Anon. Auch Brehm hatte keine Ahnung. Wir wissen nicht viel vom seltenen Wasseroppossum. Jetzt wieder im Zoologischen Garten in New York. Arche Noah, 1, 5: 102.

Krumbiegel on the waitoreki: 1949. Wunderinsel Neuseeland. Arche Noah, 1, 8: 170.

1950. Von neuen and unentdeckten Tierarten. Kosmos. Stuttgart (pp. 70-75).

1952. Das “Waitoreki”, ein angeblich neues Saugetier von Neuseeland. Zeitschrift fur Saugetierkunde (Berlin). 18: 110-115.