Art. LII.—On Two Moa-skulls in the Canterbury Museum.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 29, 1896, Page 561

Art. LII.—On Two Moa-skulls in the Canterbury Museum. By Captain F. W. Hutton, F.R.S., Curator. [Read before the Philosophical Institute of Canterbury, 6th May, 1896.] The publication in the thirteenth volume of the “Transactions of the Zoological Society of London” of the valuable paper by Professor T. J. Parker, F.R.S., “On the Cranial Osteology of the Dinornithidæ,” has enabled me to offer descriptions of two rare moa-skulls in the Canterbury Museum, which differ much from any of those described in Professor Parker's paper. In. neither case is it quite certain to which species these skulls should be referred; but, as each was found in association with a very limited number of bones, the specific names attached to them are probably correct. In describing them I have followed the terminology and measurements employed by Professor Parker. Megalapteryx tenuipes. The first skull is a much-damaged cranium which was found in a limestone cave on the Lower Buller River, together with bones of Megalapteryx tenuipes and Anomalornis parvus. As the skull of the latter is well known, it follows that one under review belongs, almost certainly, to the former species, and this is borne out by an examination of the specimen, which, although fragmentary, presents characters not found in any described genus. It is the specimen mentioned by Professor Parker in a foot-note on page 378 of his memoir. The occipital foramen is very large, and its plane about vertical; the crest is large, as in Meionornis. The occipital condyle projects considerably beyond the crest, and beyond the par-occipital processes, which are short and rounded below; the supra-foraminal ridge is not continued on them. The cranial roof is much arched, but it is so worn away that an exact description cannot be given; however, the temporal fossæ appear to resemble those of Meionornis, and there is a flat area between the temporal and lambdoidal ridges. The former of these is very slightly marked. The inferior temporal ridge is well marked, and the post-temporal fossa is moderate, being broader than in Meionornis and narrower than in Anomalornis. The roof of the orbital cavity is very flat, and is not separated by any sharp ridge from the temporal fossa—a character by which this skull can be readily recognised from any other as yet described; but there is a slight indication of the groove found in Anomalornis. The lower margin of the optic foramen is a sharp, straight shelf of bone, both it and

the pre-sphenoid fossa resembling much Pachyornis elephantopus. The inter-orbital septum is better developed than in any other species of moa yet described. The basi-pterygoid processes are slender. Length of basis cranii, 28mm.; length to olfactory chambers, 47mm.; width at temporal fossæ, 38mm.; height of cranium, 33mm.; distance between optic foramina, 9mm.; height of occipital foramen, 11mm.; width of occipital foramen, 10mm. The leg-bones—a tibia and a metatarsus—which I believe Belong to this skull have the following dimensions :— —: Length. Prox. Width. Mid. Width. Distal Width. Metatarsus 173mm. 45mm. 27mm. 74mm. Tibia 362mm. 81mm. 25mm. 27mm. Anomalornis fortis. The second of these skulls is a cranium and mandible found in a small swamp at Cheviot, together with leg-bones of Dinornis torosus, Megalapteryx tenuipes, Anomalornis fortis, and Anomalornis parvus, those of A. fortis being the most numerous. If I am right in ascribing the skull from the cave on the Buller River to Megalapteryx, it follows that the present skull belongs to Anomalornis fortis, and this opinion is considerably strengthened by the fact that the mandible bears a considerable resemblance to that of A. parvus. The cranium is considerably damaged, but the following description will show that it differs from any hitherto described skull:— Cranium.—The occipital plane is at right angles to the basi-temporal platform, and the occipital crest is low and broad, as in Pachyornis. The condyle projects beyond the crest, and beyond the par-occipital processes. These latter are damaged, but they, appear to be much the same as in Meionornis, except that they are smaller and do not project downwards to the level of the mammillar tuberosities. The supra-foraminal ridge is well marked, and can be traced on each side all down the par-occipital process. The lambdoidal ridge is simple. The cranial roof is much arched in both directions, but without any swellings. The post-orbital processes are broken off, as are also the margins of the orbits. The base of the skull also is much damaged, but the mammillar tuberosities are seen to be feeble and ridge-like, as in Meionornis. The tympanic cavity (much damaged) has its dorsal margin curved. The zygomatic process is very slender. The inferior temporal ridge is well marked, and the post-temporal fossa is very

broad, as in Anomalornis and Pachyornis, and very different from Meionornis and Euryapteryx. The temporal fossa is much the same as in Meionornis, the temporal ridge not extending much over the cranial roof, and leaving a flat area between it and the lambdoidal ridge. There is no mid-temporal ridge. The roof of the orbital cavity, from the optic foramen towards the middle of the upper margin of the orbit, is remarkably flat, and is separated from the sharp ridge which forms the anterior margin of the temporal fossa by a deep groove, as in Anomalornis. The optic foramina are damaged, but, apparently they resemble those of Anomalornis parvus. Mandible.—This is stronger and straighter than in Meionornis, but not so robust as in Anomalornis parvus, nor so pointed or so deflected as in Pachyornis elephantopus. The articular cup is much expanded, the outer border reflexed, the inner border quite low and with a pneumatic foramen on the inner surface near the end of the internal angular process. In these points it resembles the mandible of Anomalornis and Pachyornis, and differs from that of Meionornis and Euryapteryx. The symphysis is longer than in M. casuarinus, but not so long as in A. parvus, which it otherwise resembles. The ventral-ridge is fairly well marked. The following measurements are all that can be given; they are taken in the same way as those in Professor Parker's paper:— Length of basis cranii, 28mm.; length to olfactory chambers,* Measured from the centre of the occipital condyle to the anterior border of the upper portion of the septum separating the olfactory chambers from the brain-cavity. 50mm.; width at temporal fossæ, 42mm.; distance between temporal ridges, 36mm.; height of cranium, 37.5mm.; distance between optic foramina, 10mm.; length of mandibular ramus, 118mm.; greatest height, 17.5mm.; least height, 10.5mm; length of symphysis, 17mm.; width of symphysis, 22.5mm Both the cranium and the mandible closely resemble those figured by Sir R. Owen under the name of Palapteryx in “Extinct Birds of New Zealand,” pl. 45, figs. 1–7; but in our specimen the cranium is more arched, the temporal ridges do not extend so far over it, and the occipital condyle is more rounded in section. However, I believe the two to be congeneric. The cranium agrees with that of Anomalornis parvus in the broad post-temporal fossæ, the groove on the roof of the orbital cavities, and probably in the structure of the optic foramina and pre-sphenoidal fossæ. It agrees with that of Meionornis casuarinus in the shape of the temporal fossæ and

in the flat areas between the temporal and lambdoidal ridges. In the curved dorsal margin of the tympanic cavity it differs from both, but this part is much damaged. The mandible more closely resembles that of A. parvus than that of M. casuarinus; but it is slighter and more curved than in A. parvus. The pelvis and sternum, described in my paper on the moabones from Kapua,* Trans. N.Z. Inst., xxviii., p. 639, 640. are also intermediate between Meionornis and Anomalornis, but, as the pelvis, the leg-bones, and the mandible approach more nearly to the latter genus, I think the species has been rightly named. Too much importance appears to have been attached to the spread of the temporal ridges over the cranial roof, which is of specific value at most. If, however, it is thought to be generically distinct from both, it may take the name of Palapteryx. The dimensions of the leg-bones which I believe to belong to this skull are as follow :— — Length. Prox. Width. Mid. Width. Distal Width. Metatarsus 180mm. 58mm. 35mm. 81mm. Tibia 406mm. 96mm. 33mm. 48mm. Femur 245mm. 83mm. 34mm. 86mm. These measurements are much the same as those of the large form of A. parvus found in caves, and, indeed, I cannot distinguish the metatarsi of the two species, but the femur in A. fortis has the popliteal depression deeper, and the tibia is easily recognised by its not having the distal inward dilatation in the neighbourhood of the flexor bridge which makes the tibia of A. parvus look something like that of Pachyornis.