What is a Global Stratotype Section and Point (GSSP) benchmark, and what role does it play in delineating geological boundaries?

A relatively rich assemblage of starfish is recognised from the talus facies of an Upper Jurassic (lower Kimmeridgian) biohermal, sponge-cyanobacterial build-up from the Wapienno/Bielawy succession exposed in a salt-dome anticline in Kuyavia region, north-central Poland. The paper presents 8 taxa belonging to 4 genera (one new to science): Boxaster gen. nov., Noviaster Valette, 1929, Tylasteria Valette, 1929, Valettaster Lambert, 1914, and 4 families: Astropectinidae Gray, 1840, Goniasteridae Forbes, 1841, Sphaerasteridae Schöndorf, 1906 and Stauranderasteridae Spencer, 1913. Only a very few representatives of some of these taxa have formerly been reported from the Jurassic of Poland. Two species are new: Valettaster planus sp. nov. and Boxaster wapienensis gen. et sp. nov. The Jurassic starfish assemblage recognised from the Wapienno/Bielawy succession is interpreted as an offshore starfish fauna with the admixture of allochtonous shallow-water taxa. The lithology of the source deposits indicates their transport by storm agitation and/or mass movements. This fact strongly influenced the preservation state, all collected plates being disarticulated and most of them abraded.

The shallow-marine carbonate deposits of the Reuchenette Formation (Kimmeridgian, Upper Jurassic) in

northwestern Switzerland and adjacent France yield highly diverse bivalve associations, but only rarely contain

remains of pinnid bivalves. The three occurring taxa Pinna (Cyrtopinna) socialis d’Orbigny, 1850, Stegoconcha

granulata (J. Sowerby, 1822) and Stegoconcha obliquata (Deshayes, 1839) have been revised. A lectotype for

Pinna (C.) socialis was designated and the taxon is assigned herein to P. (Cyrtopinna) Mörch, 1853, the first record

of the subgenus from the Jurassic. A brief review of Stegoconcha Böhm, 1907 revealed two species groups

within the genus. Species close to the type species S. granulata are characterized by a nearly smooth anterior

shell, followed posteriorly by deep radial furrows and rows of pustules covering the dorsal flank. Another group

comprises radially ribbed species related to S. neptuni (Goldfuss, 1837). It includes among others the Paleogene

species S. faxensis (Ravn, 1902), extending the known range of Stegoconcha from the Middle Jurassic into the

Paleogene. The paper suggests a relationship between Stegoconcha and the Cretaceous Plesiopinna Amano,

1956, with S. obliquata as a possible intermediate species leading to Plesiopinna during the Early Cretaceous.

Furthermore, a possible relationship between Stegoconcha and Atrina Gray, 1842 is discussed.

Ophiuroids from the Upper Jurassic marine deposits (upper Oxfordian–lower Kimmeridgian) of southern and north-western Poland have been studied in two sections: Zalas quarry in the Kraków-Częstochowa Upland in southern Poland and Wapienno/Bielawy quarries in the Kuyavia region of north-western Poland. Described herein are nine taxa belonging to five genera (one new to science): Alternacantha Thuy and Meyer, 2013; Dermocoma Hess, 1964; Ophiobartia Loba gen. nov.; Ophioderma Müller and Troschel, 1840; Ophiotreta Verrill, 1899, and three families: Ophiacanthidae and Ophiodermatidae (both of Ljungman, 1867), and Ophiotomidae Paterson, 1985. Only a few representatives of some of these taxa have previously been reported from the Jurassic of Poland. One species, Ophiobartia radwanskii Loba, is established as new. The ophiuroid material recognized from both Polish localities is close to those described from Western Europe at family or even genus level. Both studied ophiuroid assemblages from Zalas and Wapienno/Bielawy show similarities, being dominated by the cosmopolitan species Ophioderma spectabile Hess, 1966, and by different species of Dermocoma. The recognized ophiuroid assemblages represent a rather shallow-water environment.