A specimen of little bush moa Anomalopteryx didiformis (Owen, 1844), Emeidae Bonaparte, 1854 from the National Museum of Natural History, Sofia

A complete right tarsometatarsus from an unknown site of New Zealand was identified as little bush moa (Anomalopteryx didiformis (Owen, 1844)), possibly an adult male individual.


Introduction
The specimen, described here, is the only representative of the order Dinornithiformes Bonaparte, 1852 in the collections of the National Museum of Natural History in Sofia (NMNHS). In a previous paper (Boev, 2005), it was reported as "Dinornithidae gen. indet." of "(Holocene) from an unknown locality in New Zealand". The specimen is a complete right tarsometatarsus (tmt) of very good preservation. The whole bone was burnt, an indication the species had been used as prey of local people. It was given as a gift by Dr Cyril Alexander Walker  from the Natural History Museum, London during the author's short visit in May 1986.

Material and methods
Material: tarsometatarsus dex. ad. The date, collector's name and the site are unknown.
For the species identification of this subfossil find, we used the special key for identification of the long bones of moas (Worthy, 1988). The measurements of this specimen are given in Table 1.

Results and discussion
According Worthy (1988), if the ratio TL : WD is less than 2.5, the tmt belongs to a species of Anomalopterygidae. If this ratio is 2.1-2.5, the key leads Other features that helped to identify the species as Anomalopteryx didiformis (Worthy, 1988): lateral hypotarsal ridge longer than medial (Plate 1 -b); medial nutrition foramen not in distinct hollow, bounded proximally by a ridge (Plate 1 -b); length typically 2.2 times distal width (in the specimen NMNHS 3852 it is 2.17, i. e. approx. 2.2).
The species used to be "the more common and occurred on both the North and South islands (Cracraft, 1976). According Day (1981), A. didiformis belongs to the group of the so-called "Pygmy Moas", which used to be between 90 cm and 120 cm in height.". The same is stated by Cracraft (1980). The last moas survived until 600 to 800 B.P., although "a small species of Anomalopteryx… may have survived in the remote wilderness of the Southern Alps until the eighteenth or nineteenth centuries." (Cracraft, 1980). The little bush moa used to be abundant at "slightly lower altitudes" (Worthy & Scofield, 2012).
Anomalopteryx didiformis is known from the Fern Flat, Marton, near the Waimutu Stream, the Kaimatira Pumice Sand (dated 700 000 to 800 000 years ago), Scinde Island, Hawke's Bay, Near Napier, Hawke's Bay, Gleniti Valley, Timaru, Cook Strait (New Zealand). The finds of "Timaru Basalt, would be about 2.5 m. y. old and would, therefore, be the oldest known fossil record of moa." (Worthy et al., 1991). Another locality where it has been recorded is the Takaka Fos- sil Cave on the Takaka Hill, South Island (Worthy & Roscoe, 2003). Worthy (1997) summarises that (1) A. didiformis preferred unmodified habitats, (2) it disappeared in the prehistoric time and (3) it is known from a total of 22 sites (9 on the Northern Island and 13 on the South Island).
Thus, the little bush moa is the moa species of both the oldest and the latest fossil/subfossil record of all nine species of Dinornithiformes.

Conclusions
Although relatively numerous at the paleontological and archaeological sites in the New Zealand, the little bush moa is a rarity among the avian museum collections. The examined tarsometatarsus NMNHS 3852 is one of the most valued specimens in the avian collection of fossil and subfossil birds of the NMNHS.