Main names in profile metadata
Capture surname using a metaDescribes with predicate="mainName"
metaDescribes[@predicate="mainName"]
Main name
<metaItem about="name">
<metaDescribes predicate="type">personal</metaDescribes>
<metaDescribes predicate="mainName">Lyttelton</metaDescribes>
<metaDescribes predicate="foreNames">Humphrey Richard Adeane</metaDescribes>
<metaItem about="alternative_name"><metaDescribes predicate="alt_type">variant</metaDescribes><metaDescribes predicate="foreNames">Humph</metaDescribes>
</metaItem>
</metaItem>