A review of Silurian discinoid brachiopods from Gotland, Sweden

The eurypterid record from the Prague Basin includes occasional Ludlow faunas, but in the uppermost Silurian (Přídolí) eurypterids suddenly become common in relatively deep water facies. Pterygotids clearly dominate these late Silurian faunas, whereas carcinosomatids are represented by the single species Eusarcana acrocephala, known from only a few specimens. This species is revised and its validity is discussed herein. A new eurypterid fauna found in deep water shale facies is described from the lower and middle part of the Motol Formation, Wenlock, Sheinwoodian-Homerian, Cyrtograptus murchisoni to C. lundgreni graptolite biozones, at Praha-Lochkov. It consists of common fragments of the carcinosomatid eurypterid described here as Eusarcana? sp. A and rare possible pterygotid fragments. This is the earliest evidence of carcinosomatids outside Laurentia and one of the earliest records of the group worldwide. This early occurrence outside a hypothetical Laurentian evolutionary centre is discussed with respect to the palaeobiogeography of other faunas colonising peri-Gondwanan basins after the decline of widespread early Silurian anoxia. A previous suggestion that carcinosomatids (presumed basal members of the Carcinosomatoidea) had similar distribution patterns to pterygotoids is discussed. Eurypterids migrated into the peri-Gondwanan realm from the tropical zone, but the dispersion potential of carcinosomatids into the temperate and cool water realm was probably lower than that of pterygotids. In the Prague Basin, the carcinosomatid-dominated fauna of the Wenlock age was replaced in the late Silurian by a pterygotid-dominated fauna.•

Section: Distribution Pattern Of Eurypterids In the Silurian Rocks Ofsupporting

confidence: 67%

Silurian carcinosomatid eurypterids from the Prague Basin (Czech Republic)

Budil¹,

Manda²,

Tetlie³

2014

“…The discinoideans were generally epibenthic but as shown by Bassett et al (2009) and Mergl (2010b), clustering on floating hard substrates (e.g. drifted cephalopod shells and weed tufts) was also a common life mode from the Ordovician onwards (Bassett et al 2009, Mergl 2010a). The Kosoidea-like medium to large sized discinids, having planar ventral valves and low conical dorsal valves, have been documented from Palaeozoic cool water environments (Morris & Sharpe 1846, Sharpe 1856, Reed 1925, Mendez-Alzola & Sprechmann 1971, Boucot 1975, Boucot et al 2001, Mergl & Massa 2005.…”

Section: Discinoidean Brachiopodsmentioning

confidence: 94%

Response of organophosphatic brachiopods to the mid-Ludfordian (late Silurian) carbon isotope excursion and associated extinction events in the Prague Basin (Czech Republic)

Mergl¹,

Frýda²,

Kubajko³

2018

Self Cite

The Silurian Period represents a rather unusual period in Earth history. During the last two decades several distinct and rapid changes in the Silurian global carbon cycle have been recognized. These geochemical events were closely linked to major crises in marine ecosystems as well as to palaeoclimatic changes (see Munnecke et al. 2003, Loydell 2007, Calner 2008, for reviews). The largest magnitude perturbation in the Silurian global carbon cycle, named the mid-Ludfordian carbon isotope excursion (CIE) by Kaljo et al. (1997), has been considered also to represent the largest carbon isotope excursion throughout the whole Phanerozoic and the second largest in Earth history (Munnecke et al. 2003). On the other hand, the mid-Ludfordian CIE was preceded only by moderate faunal crises referred to as the Lau conodont Bioevent (Jeppsson 1987), Kozlowskii graptolite Bioevent (Urbanek 1993), and Pentamerid Bioevent (Talent et al. 1993). The mid-Ludfordian CIE and the associated faunal turnover have been documented from many palaeocontinents, in particular from different areas of Baltica (see Kaljo et al.

“…Four Emsian and Eifelian species of Chynithele are without doubt derived from the genus Ivanothele, which is known from limestone of Wenlock age of Gotland (Mergl 2010) and tuffaceous limestone of Ludlow age in the Barrandian (Mergl 1996(Mergl , 2001. Lochkothele is known already from the Wenlock (Mergl 2006), with the next report from the Lochkovian (Havlíček & Mergl 1988).…”

Section: Ancestors Of the Emsian-eifelian Peri-reefal Lingulatesmentioning

confidence: 99%

Lingulate brachiopods from the Suchomasty Limestone (upper Emsian) of the Barrandian, Czech Republic

Mergl¹,

Jiménez-Sánchez²

2015

Self Cite

Lingulate brachiopod fauna from Suchomasty Limestone (upper Emsian, P. serotinus Zone) are examined. Eleven species were observed, of which Kosagittella robusta, Chynithele intermedia, Lochkothele rugellata and Praeohlertella lukesi are described as new taxa. Associated Opatrilkiella kobyla, Havlicekion frydai and Opsiconidion coralinus were described previously from the Chýnice Limestone of the Barrandian area. Four taxa are left in open nomenclature including further evidence of the siphonotretid Orbaspina in the upper Emsian. The composition of the fauna shows distinct difference to other Emsian and Eifelian lingulate brachiopod faunas of the Koněprusy area of the Barrandian. •