<p>The phylogeographical evolution and the consequent changing distribution and diversity of rhynchonelliform brachiopods through
the Ordovician are linked to the dynamic palaeogeography of the period. The Early Ordovician (Tremadocian and Floian) is characterized
by globally low-diversity faunas with local biodiversity epicentres, notably on the South China Palaeoplate; low-latitude
porambonitoid-dominated faunas with early plectambonitoid and clitambonitoid representatives, as well as high-latitude assemblages
mostly dominated by orthoids, can be recognized, but many taxa are rooted in Late Cambrian stocks. The Early Ordovician displays
a steady increase in rhynchonelliformean biodiversity, which was mostly driven by the increasing success of the Porambonitoidea
and Orthoidea, but the billingsellids and early plectambonitoids also contributed to this expansion. During the Early to Mid
Ordovician (Dapingian–Darriwilian), marine life experienced an unprecedented hike in diversity at the species, genus and family
levels that firmly installed the suspension-feeding benthos as the main component of the Palaeozoic fauna. However, this may
have occurred in response to an early Darriwilian annihilation of existing clades, some of which had been most successful
during the Early Ordovician. New clades rapidly expanded. The continents were widely dispersed together with a large number
of microcontinents and volcanic arcs related to intense magmatic and tectonic activity. Climates were warm and sea-levels
were high. Pivotal to the entire diversification is the role of gamma (inter-provincial) diversity and by implication the
spread of the continents and frequency of island arcs and microcontinents. The phylogeographical analysis demonstrates that
this new palaeogeographical configuration was particularly well explored and utilized by the strophomenides, especially the
Plectambonitoidea, which radiated rapidly during this interval. The porambonitoids, on the other hand, were still in recovery
following the early Darriwilian extinctions. Orthides remained dominant, particularly at high latitudes. Biodiversity epicentres
were located on most of the larger palaeoplates, as well as within the Iapetus Ocean. Provincial patterns were disrupted during
the Sandbian and early Katian with the migration of many elements of the benthos into deeper-water regimes, enjoying a more
cosmopolitan distribution. Later Katian faunas exhibit a partition between carbonate and clastic environments. During the
latest Katian, biogeographical patterns were disrupted by polewards migrations of warm-water taxa in response to the changing
climate; possibly as a consequence of low-latitude cradles being developed in, for instance, carbonate reef settings. Many
clades were well established with especially the strophomenides beginning to outnumber the previously successful orthides,
although this process had already begun, regionally, in the mid to late Darriwilian. At the same time, atrypoid and pentameroid
clades also began to radiate in low-latitude faunas, anticipating their dominance in Silurian faunas. The Hirnantian was marked
by severe extinctions particularly across orthide-strophomenide clades within the context of few, but well-defined, climatically
controlled provincial belts.
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