Dinornithiformes

Belongs within: Palaeognathae.

The Dinornithiformes, moas, are a group of moderately to extremely large flightless birds known from New Zealand (an historical record of a species from Australia was based on a specimen of mislabelled provenance) that became extinct following human colonisation of the region. The wings had been entirely lost with the pectoral girdle represented only by vestigial scapulocoracoid bones (Worthy & Holdaway 2002).

Leg or breast?

Published 24 September 2007

This page’s subject is one that is very familiar to me as a New Zealander, except it’s not really. I’ve heard of these creatures since I was a little lad, and representations of them have been almost everywhere I’ve gone. I’ve never actually seen one. I don’t know anyone who’s every seen one. Probably no-one has seen one for hundreds of years, in fact. The Dinornithiformes are but a memory these days, long since converted into quarter-pack meals for Polynesian settlers. Ka ngaro i te ngaro a te moa—lost as the moa is lost.

The taxonomy of moa is complicated, but at present there are eleven species recognised as valid*. The order was unique to New Zealand—the “Australian” Dinornis queenslandiae De Vis 1884 was based on a partial femur in the Queensland Museum, but this bone is now believed to have come from New Zealand and is assigned to Pachyornis elephantopus. In the past, Dinornithiformes has been divided into two families with the lightly built, more cursorial genus Dinornis in its own family and the other smaller and/or more heavily built genera in the Emeidae, but phylogenetic analysis has shown that Dinornis is nested within the Emeidae (Worthy & Holdaway 2002).

*Eleven species were recognised in Worthy & Holdaway (2002), the most recent major review of Dinornithiformes. Bunce et al. (2003) reduced the number of species of Dinornis from three to two (see below), but Baker et al. (2005) increased the number of species of Megalapteryx from one to two.

The photo at the top of this section (from Wikipedia) shows the reconstructed Dinornis in the Auckland Museum. This specimen has been around for some time—it was built in 1913 though when the Natural History section of the museum was rebuilt it lost the tussock-land diorama it had previously inhabited (if I recall correctly) and moved into a glass case. The Auckland Museum moa stands about three metres tall, and modern interpretations would, unfortunately, label this a severely inaccurate reconstruction. It has been mounted in an unnaturally elevated stance, and should have been much more low-slung. A more realistic reconstruction was shown on a recent stamp issue, shown below (from New Zealand Birds):

Such a lowered reconstruction significantly lowers the height, but we’re still looking at about two metres for the tallest Dinornis specimens. A moa of this size may have wighed over 150 kg (Worthy & Holdaway 2002). Other species were smaller—the smallest was Megalapteryx didinus at probably about 40 kg. The super-heavy Pachyornis elephantopus was considerably shorter than large Dinornis, but may have weighed about the same amount. The image below comes from Nature, and shows three moa species against a 1.8 metre tall human. From left to right, the moas are a female Dinornis novaezealandiae, Megalapteryx didinus and Pachyornis elephantopus.

Despite their extinction prior to European settlement in New Zealand, a surprising amount of molecular data has been gleaned from ancient DNA studies of moa. Among other things, said molecular analyses have demonstrated that Dinornis displayed the highest degree of size dimorphism known from any bird (Bunce et al. 2003). Previously Dinornis had been divided into three species on the basis of size. Bunce et al. tested DNA from Dinornis remains for female-specific markers (birds differ from mammals in that it is the female that possesses different sex chromosomes [ZW], while the male has identical sex chromosomes [ZZ]). They found that all specimens that had been assigned to the smaller ‘species’ Dinornis struthoides were male, while all specimens of the larger ‘species’ D. novaezealandiae and D. giganteus were female. Molecular phylogenetic analysis also showed that these specimens were intermingled, with the major divide in the genus being not by size but by geography—the North Island and South Island populations (both containing representatives from all three ‘species’) were distinct and were recognised as the separate (but morphologically indistinguishable) species Dinornis novaezealandiae (North Island) and D. robustus (South Island). While females showed a great deal of variation in size, the largest females would have been about 280% of the weight and 150% of the height of the largest males.

There is very little reliable information on the life habits of moa. By the time of European settlement, it had been long enough since the extinction of the moa that records of it in Maori oral tradition were seemingly few and far between, and those that were present had become significantly mythologised. Early researchers such as Owen and Haast interpreted moa as birds of open country, comparing them to modern ostriches and emus. However, the extensive New Zealand grasslands and fernlands these authors pointed to hadn’t existed prior to human settlement, so moa were undoubtedly forest birds, foragers rather than grazers as also shown by preserved gizzard contents. Dinornis and Pachyornis seem to have had more fibrous diets with gizzards containing twigs and fibrous plants such as Phormium (the New Zealand flax) while Emeus and Euryapteryx with less robust bills had more selective diets of fruit and leaves. Interestingly, a well-preserved specimen of Euryapteryx geranoides showed a massive intrathoracic loop in the trachea, 1.2 metres long. In other birds such loops are associated with the ability to make loud, far-carrying calls, so moa (or at least Euryapteryx) would have been quite vocal birds in life.

Systematics of Dinornithiformes

Characters (Worthy & Holdaway 2002): Skull with small orbits, large olfactory cavities, broad across occipital region. Basitemporal platform with prominent basipterygoid processes. Basiparasphenoidal rostrum long, with triangular expansions extending laterally beneath antorbital plate. Maxilla usually with large dorsal inflation enclosing cavity (maxillary antrum). Beak short, may be pointed or rounded, curved down at tip. 21–23 cervical, six dorsal, 18 sacral, and eleven caudal vertebrae, no pygostyle. Pelvis broad at and posterior to acetabulum. Wing entirely absent, pectoral girdle represented only by vestigial scapulocoracoid bone without glenoid facet. Sternum with well-developed lateral processes. Femur with concave articular surface for antitrochanter on pelvis, tibiotarsus with osseous bridge over tendinal groove, tarsometatarsus with two hypotarsal ridges.

<==Dinornithiformes [Anomalopterygidae, Anomalopteryginae, Dinornithes, Dinornithoidea, Emeidae, Palapterygidae]
    |--Megalapteryx Haast 1886BH05, CC10 [incl. Palaeocasuarius Rothschild 1907CC10]
    |    |--M. didinus (Owen 1883) (see below for synonymy)CC10
    |    `--M. benhami Archey 1941BH05, CC10
    `--+--Dinornis Owen 1843BH05, CC10 (see below for synonymy)
       |    |--*D. novaezealandiae Owen 1843CC10 (see below for synonymy)
       |    `--D. robustus Owen 1846 (see below for synonymy)CC10
       `--+--Pachyornis Lydekker 1891BH05, CC10 [incl. Mauiornis Oliver 1949WH02, Pounamua Oliver 1949WH02]
          |    |--P. geranoides (Owen 1848) CC10 (see below for synonymy)
          |    `--+--*P. elephantopus (Owen 1856)CC10, BH05, CC10 (see below for synonymy)
          |       `--P. australis Oliver 1949BH05, CC10
          `--+--Anomalopteryx Reichenbach 1853BH05, CC10 [=Anomalornis Hutton 1897CC10; incl. Graya Bonaparte 1856CC10]
             |    `--*A. didiformis (Owen 1843)CC10 (see below for synonymy)
             `--EmeinaeCC10
                  |--Emeus Reichenbach 1853BH05, CC10 (see below for synonymy)
                  |    `--*E. crassus (Owen 1846)CC10 (see below for synonymy)
                  `--Euryapteryx Haast 1874 (see below for synonymy)CC10
                       |--*E. gravis (Owen 1870)CC10 (see below for synonymy)
                       `--E. curtus (Owen 1846) (see below for synonymy)CC10

*Anomalopteryx didiformis (Owen 1843)^CC10 [=Dinornis didiformis^CC10, *Anomalornis didiformis^CC10, Meionornis didiformis^H79; incl. Anomalopteryx antiqua Hutton 1893^CC10, Anomalopteryx antiquus Hutton 1892^CC10, Dinornis dromaeoides Owen 1844^CC10, Anomalopteryx dromaeoides^CC10, *Graya dromaeoides^CC10, D. dromioides Owen 1846^CC10, D. (Palapteryx) dromioides^CC10, Anomalopteryx fortis Hutton 1893^CC10, Anomalornis gracilis Hutton 1897^CC10, Dinornis oweni Haast 1886^CC10, Anomalopteryx oweni^D81, Anomalornis owenii^CC10, Pachyornis owenii^CC10, Dinornis parvus Owen 1883^CC10, Anomalopteryx parva^CC10, Anomalopteryx parvus^CC10]

Dinornis Owen 1843^{BH05, CC10} [=Megalornis Owen 1843 non Gray 1841^CC10; incl. Moa Reichenbach 1853^CC10, Movia Reichenbach 1853^CC10, Owenia Gray 1855^CC10, Palapteryx Owen 1846^CC10, Tylopteryx Hutton 1891^CC10; Dinornithidae]

*Dinornis novaezealandiae Owen 1843^CC10 [=D. novaezelandiae^CC10, *Megalornis novaezealandiae^CC10; incl. D. excelsus Hutton 1891^CC10, D. firmus Hutton 1891^CC10, D. gazella Oliver 1949^CC10, D. giganteus Owen 1843^CC10, *Moa gigantea^CC10, D. gigas Owen 1846^CC10, D. gracilis Owen 1854^CC10, *Tylopteryx gracilis^CC10, D. hercules Oliver 1949^CC10, D. ingens Owen 1844^CC10, *Movia ingens^CC10, *Palapteryx ingens^CC10, D. struthioides Lydekker 1891^CC10, D. struthoides Owen 1844^CC10, *Owenia struthoides^CC10, Tylopteryx struthoides^WH02]

Dinornis robustus Owen 1846 [=D. ingens var. robustus, Palapteryx robustus; incl. D. altus Owen 1879, D. maximus Haast 1869, Palapteryx plenus Hutton 1891, D. potens Hutton 1891, D. strenuus Hutton 1893, D. torosus Hutton 1891, D. validus Hutton 1891]^CC10

Emeus Reichenbach 1852^{BH05, CC10} [incl. Meionornis Haast 1874^CC10, Mesopteryx Hutton 1891^CC10, Syornis Reichenbach 1853^CC10]

*Emeus crassus (Owen 1846)^CC10 [=Dinornis crassus^CC10, Euryapteryx crassa^CC10, Eu. crassus^CC10, Palapteryx crassus^H79, Syornis crassus^CC10; incl. Dinornis casuarinus Owen 1846^CC10, Anomalopteryx casuarina^CC10, Cela casuarinus^CC10, Emeus casuarinus^CC10, *Meionornis casuarinus^CC10, Mesopteryx casuarina^CC10, *Syornis casuarinus^CC10, Dinornis huttoni Owen 1879^CC10, Emeus huttonii^CC10, Megalapteryx huttoni^CC10, *Mesopteryx huttoni^CC10, Dinornis rheides Owen 1870^CC10, Cela rheides^CC10, Euryapteryx rheides^H79]

Euryapteryx Haast 1874 [incl. Cela Reichenbach 1853 non Moehring 1758, Celeus Bonaparte 1856 non Boie 1831, Zelornis Oliver 1949]^CC10

Euryapteryx curtus (Owen 1846) [=Dinornis curtus, Anomalopteryx curta, A. curtus, *Cela curtus, *Celeus curtus; incl. Euryapteryx exilis Hutton 1897, *Zelornis exilis, E. tane Oliver 1949]^CC10

*Euryapteryx gravis (Owen 1870)^CC10 [=Dinornis gravis^CC10; incl. Emeus boothi Rothschild 1907^CC10, Euryapteryx boothi^WH02, Eu. compacta Hutton 1893^CC10, Emeus gravipes Lydekker 1891^CC10, Eu. gravipes^CC10, Emeus haasti Rothschild 1907^CC10, Zelornis haasti^CC10, Euryapteryx kuranui Oliver 1930^CC10, Emeus parkeri Rothschild 1907^CC10, Euryapteryx pygmaeus Hutton 1891^CC10, Pachyornis pygmaeus^CC10]

Megalapteryx didinus (Owen 1883) [=Dinornis didinus, Anomalopteryx didina, Meionornis didinus, Mesopteryx didina, Mes. didinus; incl. Palaeocasuarius elegans Rothschild 1907, *P. haasti Rothschild 1907, Megalapteryx hamiltoni Rothschild 1907, *M. hectori Haast 1886, M. tenuipes Lydekker 1891, Palaeocasuarius velox Rothschild 1907]^CC10

*Pachyornis elephantopus (Owen 1856)^{CC10, BH05, CC10} [=Dinornis elephantopus^CC10, Euryapteryx elephantopus^CC10, Palapteryx elephantopus^H79; incl. D. elephantopus var. major Hutton 1875^CC10, Pachyornis immanis Lydekker 1891^CC10, Euryapteryx immanis^CC10, Pachyornis inhabilis Hutton 1893^CC10, Dinornis elephantopus var. major Hutton 1875^CC10, Pachyornis (Pounamua) murihiku Oliver 1949^WH02, Euryapteryx ponderosus Hutton 1891^CC10, E. ponderosa^CC10, Dinornis queenslandiae De Vis 1884^CC10, Dromiceius queenslandiae^CC10, Pachyornis queenslandiae^CC10, Pachyornis rothschildi Lydekker 1892^CC10, Pachyornis valgus Hutton 1893^CC10]

Pachyornis geranoides (Owen 1848)^CC10 [=Palapteryx geranoides^CC10, Anomalopteryx geranoides^CC10, Cela geranoides^CC10, Dinornis geranoides^CC10, Euryapteryx geranoides^CC10, Dinornis expunctus Archey 1927^CC10; incl. Pachyornis mappini Archey 1941^{BH05, CC10}, Pac. (Mauiornis) mappini^CC10, Pac. (*M.) septentrionalis Oliver 1949^CC10]

*Type species of generic name indicated

References

[BH05] Baker, A. J., L. J. Huynen, O. Haddrath, C. D. Millar & D. M. Lambert. 2005. Reconstructing the tempo and mode of evolution in an extinct clade of birds with ancient DNA: the giant moas of New Zealand. Proceedings of the National Academy of Sciences of the USA 102 (23): 8257–8262.

Bunce, M., T. H. Worthy, T. Ford, W. Hoppitt, E. Willerslev, A. Drummond & A. Cooper. 2003. Extreme reversed sexual size dimorphism in the extinct New Zealand moa Dinornis. Nature 425: 172–175.

[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4^th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.

[D81] Day, D. 1981. The Doomsday Book of Animals: A unique natural history of three hundred vanished species. Ebury Press: London.

[H79] Haast, J. von. 1879. Geology of the Provinces of Canterbury and Westland, New Zealand. A report comprising the results of official explorations. “Times” Office: Christchurch.

[WH02] Worthy, T. H., & R. N. Holdaway. 2002. The Lost World of the Moa: Prehistoric life of New Zealand. Indiana University Press: Bloomington (Indiana).