Identification, classification, and growth of moa chicks (Aves: Dinornithiformes) from the genus Euryapteryx.

Leon Huynen,Brian J Gill,Anthony Doyle,David M Lambert,Craig D Millar,Tom Gilbert

doi:10.1371/journal.pone.0099929

Leon Huynen, Brian J Gill + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0099929

Copy DOI

Abstract

BackgroundThe analysis of growth in extinct organisms is difficult. The general lack of skeletal material from a range of developmental states precludes determination of growth characteristics. For New Zealand's extinct moa we have available to us a selection of rare femora at different developmental stages that have allowed a preliminary determination of the early growth of this giant flightless bird. We use a combination of femora morphometrics, ancient DNA, and isotope analysis to provide information on the identification, classification, and growth of extinct moa from the genus Euryapteryx.ResultsUsing ancient DNA, we identify a number of moa chick bones for the species Euryapteryx curtus, Dinornis novaezealandiae, and Anomalopteryx didiformis, and the first chick bone for Pachyornis geranoides. Isotope analysis shows that ∂15N levels vary between the two known size classes of Euryapteryx, with the larger size class having reduced levels of ∂15N. A growth series for femora of the two size classes of Euryapteryx shows that early femora growth characteristics for both classes are almost identical. Morphometric, isotopic, and radiographic analysis of the smallest Euryapteryx bones suggests that one of these femora is from a freshly hatched moa at a very early stage of development.ConclusionUsing morphometric, isotopic, and ancient DNA analyses have allowed the determination of a number of characteristics of rare moa chick femora. For Euryapteryx the analyses suggest that the smaller sized class II Euryapteryx is identical in size and growth to the extant Darwin's rhea.

Highlights

The analysis of growth in extinct organisms is difficult
Adult moa ranged in size from less than 20 kg for the small coastal moa Euryapteryx curtus curtus to over 200 kg for the South Island giant moa Dinornis robustus [2]
How moa grew is largely unknown with most published work comparing moa to the growth characteristics of their extant relatives [2,3]

Summary

Introduction

The general lack of skeletal material from a range of developmental states precludes determination of growth characteristics. For New Zealand’s extinct moa we have available to us a selection of rare femora at different developmental stages that have allowed a preliminary determination of the early growth of this giant flightless bird. We use a combination of femora morphometrics, ancient DNA, and isotope analysis to provide information on the identification, classification, and growth of extinct moa from the genus Euryapteryx. In depth analysis of growth in ancient animals is often limited due to the scarcity and degraded nature of skeletal material or tissues of different ages. The rare occurrence of different aged bones for New Zealand’s extinct ratite moa (Aves: Dinornithiformes) has made any analysis of moa growth difficult [1,2,3]. Recent work analysing cortical growth marks in moa limb bones suggest that, unlike their modern relatives, moa had a long pre-adult growth period [5]

Methods

Results

Conclusion