Art. III.—New Species of Moas.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 25, 1892, Page 6

Art. III.—New Species of Moas. By Captain F. W. Hutton, F.R.S. [Read before the Philosophical Institute of Canterbury, 2nd November, 1892.] Since I wrote my paper on “The Moas of New Zealand,” which I read to the Institute last year, I have seen Mr. R. Lydekker's valuable Catalogue of the Fossil Birds in the British Museum, and I have also been able to study the whole of the magnificent collection of moa bones in the Canterbury Museum, of which I had formerly seen only a portion. This collection was commenced in 1866 by Sir J. von Haast with bones from Glenmark, and he afterwards added others, principally from Shag Point and Whangarei. Last year, when Mr. H. O. Forbes was curator, he secured the collection found at Enfield, near Oamaru, and gave the greater part of it to the Museum. Mr. A. Hamilton has also contributed a good collection from the Te Aute Swamp; and during this year a small number of bones from Hamilton and other places have been obtained by exchange. I am far from having finished my examination of this collection, but, as it has become my duty to arrange and name it, I think it will be advisable to publish at once the changes to which I have been led in my views on the classification of the moas, as well as to give descriptions of five new species which I think it necessary to make. I have also thought that it would be useful to others if I published the average dimensions of the leg-bones of the moas found at Enfield. There is in the Museum an imperfect skeleton of an individual bird the metatarsus of which is similar to the larger of the two described by Sir R. Owen as D. elephantopus; but the skull has a pointed beak, and the vertebræ are of a dif-

ferent type from those found at the sandhills at the mouth of the Shag River associated with skulls with rounded beaks. This larger species of elephantopus forms the type of Lydekker's genus Pachyornis, and the genus Euryapteryx will contain only the blunt-beaked species E. ponderosa and E. gravis. I find also from the Shag Point collection that the sternum of Euryapteryx resembles that of Mesopteryx (or Syornis), but is more robust and has no pneumatic depressions at the inner anterior corners. An examination of the collection from Enfield has shown me that rheïdes and casuarina are congeneric with didina, and will all come into the genus Mesopteryx, distinguished by its slender pointed beak and shallow temporal fossæ. This leaves crassus isolated; and, for the present, it must take Reichenbach's generic name of Emeus. The skeleton of Emeus is, however, very imperfectly known. A skull from Enfield, which I refer to it, comes near Mesopteryx, but has narrower and deeper temporal fossæ. The sternum which I refer provisionally to Emeus resembles that of Euryapteryx, but has slight pneumatic depressions. In fact, Emeus appears to be intermediate between Mesopteryx and Euryapteryx, and further information is necessary before we can say whether it should be joined to either of them. It may be thought by some that too many species of moas have already been made; but with this I cannot agree. The study of individual skeletons has shown me that bones, which I formerly regarded as being merely varieties of one species, belong really to different genera; and the more I study the moas the more I see the necessity of limiting the amount of variation allowed to each species. An important biological problem, perhaps not found elsewhere, is presented to us in the development of the moas. This is the variation of an herbivorous race of animals, well supplied with food, and without the check due to the presence of carnivorous mammals preying on them. This problem can only be attacked by studying closely the distribution of the moas both in time and in space; and to do so it is necessary that the species should be closely defined. Again, the relative ages of our Pliocene and Pleistocene terrestrial deposits can probably only be ascertained by the help of moa bones, and here, again, unless the different species and varieties are kept separate, we can never obtain the data necessary to settle these questions. It may, however, be said, Why give them all names? Why not consider them as varieties of a few species? The answer is that there is still plenty of room for varieties within the limits of these species. For example, individuals of Dinornis robustus and D. strenuus from Enfield are larger than those from Hamilton. The specimens of D. torosus from Enfield

have the metatarsus more robust and its trochleæ more expanded than those from Glenmark. The representatives of Mesopteryx casuarina at Enfield have the tibia about 17.5in. long, while in those from Hamilton it averages 18.25in. These instances are sufficient to show that the species are not more restricted than is necessary for convenience of description. If they were made larger we must either use a cumbersome system of sub-varieties; or else, by clubbing varieties together, lose all chance of solving our problems. No one, I presume, at the present day would refuse to recognise two species because intermediate links had been found. This is a pre-Darwinian idea, which means that before a group of individuals may be allowed to form a distinct species all the steps of the ladder on which it rose must be destroyed. This would be a very hard rule for the palæontologist to obey, for he would have to examine and classify the mutations by which one species changed into another without being allowed to give distinct names to any of them. The difficulties involved in making a correct classification of the moas are due partly to the gradation of characters during the long interval between the earliest and latest forms known: partly to their extraordinary number, through which bones belonging to some three or four genera and ten or twelve species are usually found mixed together: and partly to collectors who either do not preserve intact individual skeletons or, what is much worse, add a bone or two to make a skeleton more complete. These difficulties are so great that the task of straightening things out appears almost hopeless. Nevertheless they must be faced if the problems I have mentioned are to be solved; and we can only hope that by constantly correcting our mistakes they may in time gradually disappear, and we shall then be able to write the remarkable history of the development of the moas in New Zealand in considerable detail, and with considerable confidence that we are giving a fairly-true representation of what really took place. Descriptions of New Species. Dinornis strenuus. This species contains all the birds from the South Island which have, up to now, been included in D. struthioides. I formerly thought that the differences between the birds of the two Islands were not sufficient to separate them; but I find that those from the South Island have constantly the metatarsus more robust, and with more widely diverging trochleæ than those from the North Island. In D. strenuus also the tibia is rather shorter and more robust than in D. struthioides. These differences—which will be seen in the following table—when combined with a difference in geo-

graphical distribution, are, I think, sufficient to constitute distict species. — Length. Proximal Width. Width of Shaft. Distal Width. Metatarsus. D. struthioides 11.5 3.0 1.5 3.8 D. strenuus 11.1 3.4 1.6 4.6 Tibia. D. struthioides 23.0 5.3 1.6 3.0 D. strenuus 22.0 5.3 1.7 3.1 Femur. D. struthioides 11.0 4.0 1.7 4.4 D. strenuus 10.5 3.5 1.7 4.1 At Enfield most of the metatarsi had a length of about 11.75in. (298mm.), but one pair measured only 11.0in. (289mm.), with the shaft as broad as in the larger birds. This small individual may perhaps have been of the opposite sex to the larger individuals; but intermediate sizes were found, both at Hamilton's and Glenmark. The average dimensions of the bones obtained at Enfield will be found in the table at the end of the paper. Anomalopteryx fortis. The bones on which I found this species are three mettarsi, a tibia, and three imperfect femora from Glenmark. The metatarsus has a length from 8.3in. to 7.8in. (208mm. to 198mm.: width at the proximal end, 2.7in. to 2.4in. (68mm. to 61mm.); at the middle of the shaft, 1.5in. (38mm.); and at the distal end, 3.6in. to 3.3in. (91mm. to 84mm.). It is remarkable for the shaft not tapering downwards; for the slight expansion of the proximal end; and for the existence of a considerable depression on the anterior surface of the middle trochlea near its base. The intercondylar ridge is high and the depressions nearly equal in depth; the inner margin of the entocondylar depression is flat and without a median ridge; the hypotarsal ridges (talon) are subequal. The trochleæ resemble those of A. didiformis, but the intertrochlear gorges are still more expanded at the bottom. These metatarsi are easily distinguished from those of Mesopteryx casuarina by the slightly-expanded proximal end, and by the remarkable depression on the anterior face of the middle trochlea. In both these points they resemble the metatarsi of A. didiformis; but in that species the depression is not nearly so well marked and the metatarsi are much smaller.

The tibia has a length of 17.5in. (445mm.); the proximal width is 4.6in. (117mm.); width of the shaft, 1.4in. (36mm.); and distal width, 2.1in. (53mm.). The antero-external surface is slightly rounded. The distal end of the specimen is unfortunately partly destroyed, but it shows the extremity to be less expanded than in M. casuarina. From the tibia of Megalapteryx the present tibia differs in being more expanded at the proximal end. The femur has an average length of 9.8in. (249mm.); the proximal width is 3.3in. (84mm.); the width of the shaft is 1.4in. (35mm.); and the distal width, 3.5in. (89mm.). The popliteal area is but slightly depressed and not well marked off, by which character it can be distinguished from the femur of Palapteryx plena. The head rises slowly; the linea aspera is fairly well marked, but there is a smooth space between the rough tubercle below the nutrient canal and that on the inner side of the popliteal area. This character distinguishes it from the femora of Mesopteryx, Palapteryx, and Megalapteryx; the popliteal area is also shorter than in Megalapteryx. The shaft is more curved anteriorly than in A. didiformis, but less so than in Megalapteryx tenuipes (Lydekker). From the femur of M. casuarina it can also be distinguished by being slighter, by having a shorter head, and by not being so expanded distally. I append a table of measurements in which are included the leg-bones of an individual skeleton of A. parva, from a cave at Highfield, near Waiau. It will be seen that this specimen has a longer and more slender femur than A. didiformis, the dimensions of which are taken entirely from North Island birds. This, however, seems hardly sufficient to entitle it to rank as a separate species. — Length. Proximal Width. Width of Shaft. Distal Width. Metatarsus. A. fortis 8.0 2.5 1.5 3.5 A. didiformis 6.3 2.1 1.2 2.8 A. parva 6.3 2.0 1.2 2.6 Tibia. A. fortis 17.5 4.6 1.4 2.1 A. didiformis 13.3 3.3 1.1 1.8 A. parva 13.7 3.5 1.2 1.8 Femur. A. fortis 9.8 3.3 1.4 3.5 A. didiformis 8.0 3.0 1.3 3.2 A. parva 8.5 2.8 1.1 3.0

Euryapteryx compacta. This species is founded on a tibia from Enfield which closely resembles that of E. gravis, but is much smaller. From the tibia of M. didina it is distinguished by its greater robustness, and its greater width at the distal extremity. The distal extremity is, however, not expanded inwards as in Pachyornis, which at once distinguishes this tibia from that of P. pygmœus. Length, 15.2in. (386mm.); proximal width, 4.6in. (117mm.); width at middle of shaft, 1.6in. (39mm.); at distal end, 2.4in. (61mm.). The metatarsus which I place with this tibia much resembles that of P. pygmœus, but has the trochleæ considerably more expanded. Its length is 7.2in. (183mm.); the proximal width, 2.8in. (71mm.); middle of shaft, 1.6in. (41mm.); and distal width, 3.4in. (86mm.). The femur, which I have added with great hesitation, resembles that of M. didina, but has a larger head. Length, 9.1in. (231mm.); proximal width, 3.5in. (89mm.); width at middle, 1.4in. (36mm.); distal width, 3.6in. (91mm.). The association of these bones with the tibia is provisional only until further information is obtained; but the tibia cannot be placed in any previously-described species. Pachyornis inhabilis. This species is founded on an incomplete individual skeleton in the Canterbury Museum, the exact locality of which is not known, but probably it was found somewhere in Canterbury. It consists of the leg-bones, fifteen phalanges, a fragment of the pelvis, and six vertebræ. The metatarsus has a length of 8.5in. (216mm.); the proximal width is 3.8in. (96mm.); width of the shaft, 2.0in. (51mm.); and distal width, 4.5in. (114mm.). The inner margin of the entocondylar depression has no median ridge, and the hypotarsal ridges (talon) are equal. The bone much resembles the metatarsus of Euryapteryx ponderosa, but is not so robust; also the posterior surface of the middle trochlea rises abruptly from the shaft, and nearly at right angles with it, while in E. ponderosa it is very oblique, and merges more or less gradually into the shaft. From the metatarsus of E. gravis the present species can be recognised by being more expanded proximally. The tibia has a length of about 19.5in. (495mm.); the width of the shaft is 1.8in. (46mm.); and the distal width, 3.3in. (84mm.). It has the great inward expansion at the distal end, which is one of the characters of Pachyornis, and which distinguishes that genus from Euryapteryx. The femur has a length of about 11.5in. (292mm.); the proximal width is 4.5in. (114mm.); the width of the shaft, 2.0in. (51mm.); and the distal width is 5.0in. (127mm.). The

popliteal area is very broad, as in Pachyornis elephantopus and E. ponderosa, but it differs from both in not having the rough line along the inner side of the popliteal area broken by a smooth groove; the head also does not rise so rapidly as in either of those species. The vertebræ show considerable differences from those of P. elephantopus, especially in the centra of the cervicals being more compressed. These differences may be, perhaps, of generic value; but, until the skull is known with certainty, it is better to keep it, as well as the next species, in Pachyornis. This species also occurred at Glenmark and at Hamilton's; but the typical form was not found at Enfield. There were, however, a few specimens of a larger bird which, for the present, I refer to this species, although it may probably be distinct. The metatarsus is 9.5in. and the tibia 20.5in. in length. The other dimensions will be found in the table at the end of the paper. Pachyornis valgus. This-species is founded on a pair of tibiæ from Enfield, so different from any others in the extraordinary internal expansion of the distal end that I feel compelled to distinguish them under a separate name. The dimensions are as follow: Length, 18.0in. (457mm.); Proximal width, 5.7in. (143mm.); width of shaft, 1.7in. (43mm.); distal width, 3.3in. (84mm.). This distal expansion of the tibia, nearly twice that of the shaft, is not really greater than in the smaller species of Dinornis, but it takes place so much more rapidly that it is much more conspicuous. The metatarsus which I associate with these tibiæ has a length of 8.5in. (216mm.); the proximal width is 3.5in. (89mm.); the width of the shaft, 1.9in. (48mm.); and the distal width is 4.2in. (107mm.). It closely resembles the same bone in E. crassus, and can only be distinguished from it by the greater proximal width, necessary to articulate with the expanded distal end of the tibia. A similar metatarsus is in the collection from Glenmark, and there were one or two in the Hamilton swamp, but I never before saw a tibia like the present one. I have also temporarily placed here a pair of femora from Enfield, very different from any others, and for which I can find no other place. The length is 11in. (279mm.); proximal width, 4.0in. (101mm.); width of shaft, 2in. (51mm.); distal width, 5.0in. (127mm.). They are specially remarkable for the short head combined with a very stout shaft.

Dimensions of Enfield Moa-Bones. Met. Tib. Fem. Met. Tib. Fem. Met. Tib. Fem. Met. Tib. Fem. Met. Tib. Fem. D.validus. D.robustus. D.potens. D.torosus. D.strenuus. Length 19.0 33.3 16.0 16.7 13.2 15.0 14.7 29.0 13.7 12.6 24.5 12.5 11.3 22.1 Width (prox.) 4.7 7.2 6.0 4.7 7.5 5.4 4.3 6.6 5.2 3.7 5.7 4.3 3.4 5.5    "   of shaft 2.1 2.5 2.3 2.1 2.5 2.4 1.9 2.3 2.3 1.6 1.7 1.9 1.6 1.7    "   distal 6.2 4.7 6.5 6.2 4.3 6.0 5.4 4.1 6.0 5.2 3.4 5.4 4.5 3.3 M.rheides. M.casuarina. M.didina. E.crassus. P.inhabilis. Length 9.1 19.2 11.3 8.1 17.4 9.7 7.1 15.0 9.1 8.7 19.7 11.3 9.5 20.5 11.9    "   (prox.) 3.0 5.4 4.3 3.1 4.8 3.7 2.5 4.2 4.7 3.2 6.0 4.3 3.9 6.4 4.5    "   of shaft 1.6 1.7 1.8 1.6 1.6 1.5 1.4 1.5 1.4 1.9 1.8 1.7 2.1 1.9 1.8    "   distal 4.0 2.8 4.7 3.8 2.5 4.0 3.2 2.2 3.7 4.2 3.0 4.9 4.8 3.4 5.3 P.valgus. P.pygmæus. P.elephantopus. E.ponderosa. E.gravis. Length 8.5 18.0 11.0 6.8 16.7 9.5 9.7 23.0 13.0 8.5 19.5 11.4 7.5 18.0 10.8    "   (prox.) 3.5 5.7 4.0 2.8 4.9 3.9 4.3 9.0 5.6 3.8 6.1 4.7 3.0 5.4 3.8    "   of shaft 1.9 1.7 2.0 1.6 1.5 1.6 2.7 2.3 2.3 2.3 2.1 2.1 1.9 1.8 1.9    "   distal 4.2 3.3 5.0 3.4 2.6 4.1 6.0 4.1 6.2 4.9 3.2 5.2 4.1 2.7 4.5