Chotecops

Abstract: Three new phacopid trilobites from the lower horizons of the Yeringberg Formation at Seville, Victoria are described. Paciphacops edgecombei sp. nov. occurs in a mudstone facies, and Reedops albertii sp. nov. and Chotecops chlupaci sp. nov. occur together in a calcareous siltstone facies. The latter are the only known representatives of their genera in Australia. A review of Reedops and Paciphacops (including the revision of Phacops mansfieldensis Etheridge & Mitchell, 1896 from Loyola, Victoria) establishes late Lochkovian to early Emsian, and Ludlow to Pragian stratigraphic ranges for these genera respectively. The occurrences of these phacopid genera at Seville indicate placement of the Pragian-Emsian boundary low in the Yeringberg Formation, but above the trilobites. A facies succession including the trilobite-bearing beds at Seville is considered to reflect a widely documented late Pragian regression, and further supports a late Pragian age for the fauna.

Abstract: The trilobite assemblage of Calceola-bearing beds in the upper part of Acanthopyge Limestone (Chotec Formation, Eifelian) in the Koněprusy area, the Czech Republic, is described. Together with occurrence of Calceola, it indicates absence of significant palaeogeographic barriers restricting the distribution of the Rhenish-Type faunas in the Middle Devonian. The generic composition of the gathered trilobite assemblage somewhat differs from typical Acanthopyge-Phaetonellus assemblage characteristic for the Acanthopyge Limestone facies in possible absence and/or very rare occurrence of Phaetonellus, and only infrequent occurrence of Acanthopyge. Phacopid Chotecops cf. hoseri (Hawle et Corda, 1847) distinctly dominates; all other taxa are rather rare. Important is an occurrence of scutelluids of the Scutellum sensu lato group (preservation of remains does not enable more precise determination) and Longiproetus(?). Trilobite remnants are generally poorly preserved and very fragmented (only minute shields are not affected), which support a high-dynamic, shallow-water original environment.

Abstract: Trilobites are important elements of the Devonian macrobenthos; some of them were collected in the Chefar el Ahmar Formation, from two sections located near Beni Abbes in the Saoura Valley (Ougarta Basin, Saharan Algeria). This formation is characterized by alternations of claystones and limestones, and it is considered to be late Emsian to early Frasnian in age. Only the lower part of this formation has yielded trilobites so far; their presence has been known for a long time. Phacopines clearly dominate the trilobite assemblages, with Austerops, Barrandeops, Chotecops and Phacops s.l. as the main genera. Two new species are described (Austerops salamandaroides sp. nov. and Phacops ouarouroutensis sp. nov.), while some other taxa are presented in open nomenclature. Comparisons are made with closely allied species. These new trilobite occurrences have been analysed in terms of their intra- and interspecific variability and biodiversity. The occurrence of Struveaspis maroccanica, previously known from the Saoura Valley, provides an early Eifelian age, which is also confirmed by the presence of trilobites Thysanopeltis and Koneprusites, and ostracods Bairdiocypris devonica and Bufina ?subovalis.