Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 75, 1945-46
Previous Article | Table of Contents | Next Article
This text is also available in PDF
(918 KB) Opens in new window
– 319 –

A Note Concerning the Occurrence and Life-History of Leiopelma Fitzinger.

By N. G. Stephenson and Elsie M. Thomas, University, Auckland.

[Read before Auckland Institute, April 18, 1945; received by Editor, April 19, 1945; issued separately, December, 1945.]

The occurrence of two species, Leiopelma archeyi and Leiopelma hochstetteri, was first postulated by Turbott (1942). His conclusions were based mainly on considerations of size, colour, presence or absence of a web, and differences of habitat.

Concerning the habitat of Leiopelma hochstelteri, Turbott states: “…. One finds it, throughout its range, living in water at the edge of streams or in swampy areas. The adult is normally found sitting immersed in water except for the eyes and nostrils…. It has been found only in streams surrounded by forest, or in swampy ground with plenty of protecting swamp plants…. The half-webbing in the toes of the adult may be regarded as being related to this close dependence on surface water.” Again, “…. At Tokatea, in December, 1938, I found L. archeyi restricted to the topmost zone, where it was breeding. At a lower altitude, on the eastern side of the range, but still only several hundred yards from the ridge-top, L. hochstetteri was common in wet, gold-mining drives and stream-beds. Thus, here, although L. archeyi and L. hochstetteri live near each other, the narrow barren zone between the two species must be regarded as a material barrier, if only during the dry period of the breeding season in November and December.”

While it is true, generally, that the partially webbed frog, described by Turbott as L. hochstetteri, has been commonly observed to be confined to stream-beds (although it is by no means always actually immersed in water), our recent field observations dispose of the idea that the habitat of this frog is necessarily limited to such situations. It has become apparent, too, that there is no “material” or physiographic barrier separating L. hochstetteri from L. archeyi and that these two species, if true species they should prove to be, actually overlap in their range.

Observations made on Mt. Moehau, in November, 1944, indicated that the two types existed in closer proximity than had been formerly supposed. On the eastern face of Mt. Moehau, about half a mile from the summit, a specimen of the L. hochstetteri type was found in a small waterhole in the course of a partly dried-up stream-bed. Slightly higher up, some five yards from the bank of the stream and less than 10 yards from the spot where the webbed specimen was found, a small, reddish specimen of the L. archeyi type was discovered beneath a log.

By far the most significant discovery, however, was made at Tokatea, on December 10, 1944. In a patch of bush on the eastern face of the ridge, about three miles north of the saddle, and at a height of approximately 1,500 feet, a gravid female, indistinguishable

– 320 –

from the typical stream type of L. hochstetteri, was found under a moss-covered stone. Beneath the same stone, a green and brown mottled frog conforming in all details to the description of L. archeyi was discovered. This frog was also a female, but with eggs less well-developed than those of the larger specimen. (Vide photographs of specimens A and B.)

During December, 1944, and January, 1945, six more specimens of the hochstetteri type, which proved to be females, were found at Tokatea, mainly fairly close to the original locality and all within two or three yards of specimens of the archeyi type. The nearest stream was about half a mile away down the slope, but because of the impenetrable character of the bush, the distance was not accurately measured.

The examination of the ovaries of the females found at Tokatea, taken in conjunction with evidence derived from the condition of certain gravid females from Huia, suggests very strongly that the embryos of the hochstetteri type also undergo an intracapsular development on land and that an aquatic tadpole stage which has been suggested for this frog does not, in fact, exist.

Measurements of the body length of 14 specimens of the archeyi type, from the neighbourhood of Tokatea, are given in the following table:—

Tip of Snout to Vent.
(Measurements in millimetres.)
28 32 34 35
31 33 35 36
31.5 33 35 41
32 33

Although Turbott gives the maximum length from tip of snout to vent as 32 mm., it will be seen that most of the individuals examined exceeded that length. In fact, the largest of them is comparable in size with L. hamiltoni, the measurement of McCulloch's holotype (1919) of the latter species being 42 mm. It seems then that the significance of body length as a specific character must be revised. Similarly, colour and pattern do not seem to be specifically characteristic.

Although these and several other matters in connection with the genus still leave room for difference of opinion, we hope that a series of studies now in progress on the structure, ecology, and development of Leiopelma will settle conclusively the points at issue.

Acknowledgment.

The writers gratefully record their thanks to Mr. W. R. McGregor for valuable suggestions and criticism.

References.

Archey, Gilbert, 1922. The Habitat and Life History of Liopelma hochstetteri. Rec. Canterbury Mus., vol. 2, no. 2, pp. 59–71.

— 1935. Frogs in New Zealand. Bull. Auckland Zool. Soc., no. 2, pp. 5–8.

McCulloch, A. R., 1919. A New Discoglossoid Frog from New Zealand. Trans. N.Z. Inst., vol. 51, pp. 447–449. (Supplementary Note, pp. 448–449 by Charles Hedley.)

Furbott, E. G., 1942. The Distribution of the Genus Leiopelma in New Zealand, with a Description of a New Species. Trans. Royal Soc. N.Z., vol. 71, part 4, pp. 247–253.

Picture icon

LeiopelmaFig. 1.—Specimen A. gravid female, hochstetteri type. Ventral view. Fig. 2.—Specimen B, female, archeyi type. Ventral view.Specimens A and B found together on the Tokatea Ridge, Coromandel.

Picture icon

Leiopelma.
Fig. 3.—Specimen A, partially dissected to show ovaries.
Fig. 4.—Specimen B, ovaries and oviducts displayed.

Previous Article | Table of Contents | Next Article