In 1981, the American Museum of Natural History invited a group of Horse specialists at a "New York International Hipparion Conference" with many purposes. One of them was to bring together for the duration of the conference original interesting specimens, in particular skulls, dispersed through various collections, and make casts of them.
Another was to initiate an international cooperation on a subject much too vast to be dealt by any isolated specialist. This implied that the specialists would agree to use the same methodology for observations and measurements of Hipparion fossils, in order to share their data. Since I have been observing and measuring Equus and Hipparion for ca. 10 years, my methodology (elaborated from Gromova’s after discussions with C. De Giuli and P. Sondaar) was proposed as a basis for discussion. Naturally enough, the final recommended methodology turned out to be quite different of my basis: it had now to include new characters such as the observation and measures of the Pre-Orbital Fossa (POF), the measures of the lateral digits, and other features. But a number of my measures were also suppressed, or slightly modified, and the whole numerotation was changed.
[For me it was a disaster. After ten years of practice, I had to shift to an altogether different system, which, moreover, I did not find really satisfying. After the conference, I worked some months with the new system but eventually I had to compromise with my ancient way. The result was an awful mess...]