Myodocope ostracods from the Silurian of Australia

Abstract

The Silurian of Australia contains at least three genera (one new, Canalarta gen. nov.) and three species (two new, Canalarta papata sp. nov. and Bolbozoe beccata sp. nov.) of myodocope ostracods. These fossils were recovered from clastic sedimentary deposits in the lower Silurian (probably Homerian) Walker Volcanics unit of New South Wales that may represent mudflow deposits. In having the youngest occurrence of Entomozoe aff. tuberosa and the oldest known Bolbozoe species, the Australian myodocopes represent a chronologically intermediate assemblage between previously known early and late Silurian myodocope faunas. Several fossil groups from the Silurian of Australia, such as ostracods, trilobites, brachiopods and corals, apparently have a cosmopolitan distribution at generic level. The presence of many continental and micro-continental landmasses that existed along and within the tropical pan-Tethyan seaway, together with the prevailing ocean circulation, could explain this distributional pattern. The depositional setting, sedimentary deposits and faunal associates do not provide conclusive evidence concerning the lifestyle of the Australian myodocopes. They could represent nektobenthic species, as has been suggested for other early to mid Silurian myodocopes, or hyperbenthic/pelagic species, as was proposed for known late Silurian forms

A high-precision global biostratigraphy of myodocope ostracods for the Silurian upper Wenlock Series and Ludlow Series

“…Additionally, they are present, but poorly constrained stratigraphically, in the Talmakent region of Morocco (Wenlock or Ludlow Series; Vannier ) and in eastern Gondwana they are recorded from Australia in the probable Homerian Walker Volcanics of the Canberra District (Perrier et al . 2014a).…”

“…tuberosa ; Perrier et al . 2014a), the Gorstian ( scanicus graptolite biozone) of Denbighshire and in the upper Ludfordian of the Long Mountain ( E . aff.…”

“…; Perrier et al . , , ,b,c, , ,b) and that there is the prospect of establishing a myodocope ostracod biostratigraphy of comparable resolution to coeval graptolite/chitinozoan/conodont biozones, especially for the upper Wenlock Series and Ludlow Series.…”

Cosmopolitan myodocope ostracods from the Silurian of Uzbekistan, Central Asia

“…-Bolbozoe anomala Barrande, 1872; subsequent designation by Bassler and Kellett, 1934 Stratigraphic and geographic range. -Upper part of the Wenlock Series, Silurian, to Emsian Stage, Devonian; Czech Republic (Perrier et al, 2011), France (Perrier et al, 2011), Sardinia (Gnoli et al, 2009), China (Wang, 2009), Australia (Perrier et al, 2014c), Wales (Perrier et al, 2019a) and Poland (Perrier et al, 2019b). (Kříž, 1992).…”

“…Though the Uzbek material is poorly preserved its features are diagnostic of B. anomala. It differs from other smooth species of Bolbozoe by its rounded shape (B. pisttaca is elongated;Perrier et al, 2019a), its tiny rostrum (B. beccata has a prominent beak-like rostrum;Perrier et al, 2014c) and the lack of a well-developed caudal process (present in B. acuta;Perrier et al, 2011Perrier et al, , 2019a.Stratigraphic and geographic range. -Ludlow Series, North Nuratau Ridge, Uzbekistan.…”