Acta Geologica Polonica, Vol. XX (202X), No. X, pp. xxx–xxx DOI: 10.24425/agp.2020.134566 Taxonomic revision of the Paradoxididae Hawle and Corda, 1847 from the Miaolingian (Cambrian) of the Holy Cross Mountains, Poland: a morphometric approach to simply deformed trilobites JAKUB NOWICKI and ANNA ŻYLIŃSKA Faculty of Geology, University of Warsaw, Żwirki i Wigury 93, PL-02-089 Warsaw, Poland. E-mails: [email protected]; [email protected]* * corresponding author ABSTRACT: Nowicki, J. and Żylińska, A. XXXX. Taxonomic revision of the Paradoxididae Hawle and Corda, 1847 from the Miaolingian (Cambrian) of the Holy Cross Mountains, Poland: a morphometric approach to simply deformed trilobites. Acta Geologica Polonica, XX (X), xxx–xxx. Warszawa. The taxonomy of simply deformed paradoxidids from the Miaolingian (Cambrian) of Słowiec Hill, Holy Cross Mountains, Poland, is revised based on morphometric analysis. The material represents two species: Acadoparadoxides slowiecensis (Czarnocki in Orłowski, 1965) and Hydrocephalus? polonicus (Czarnocki in Orłowski, 1965). A new assemblage zone based on the combined although not precisely known ranges of these two taxa is suggested replacing the previous Paradoxides polonicus Zone of Orłowski (1975, 1988, 1992a). The Acadoparadoxides slowiecensis–Hydrocephalus? polonicus Assemblage Zone corresponds to the middle and upper part of the Wuliuan Stage (lower Miaolingian). Key words: Paradoxididae; Miaolingian; Cambrian; Holy Cross Mountains; Geometric mor- phometry; Simple deformation; Słowiec Hill This paper is dedicated to the memory of Professor Stanisław Orłowski (1931–2021) INTRODUCTION the latter paper in reviewing simply deformed par- adoxidiids from the Miaolingian (Cambrian) of the Tectonic deformation often leads to problems in Holy Cross Mountains in central Poland. The endemic determining the identity of a fossil sample. Since paradoxidiid assemblage from Słowiec Hill can be this problem is widely present when working with used as a good example of the use of a newly devel- trilobite remains, the need for resolving such cases oped workflow for this type of data. Furthermore, has resulted in the developing of tools that use mor- the much needed redescription of species from this phometry to deal with such issues. The first attempts locality (the most recent study of the paradoxidiids included linear measurements (e.g., Hughes and Jell from this locality was in Orłowski 1985) is the basis 1992), but recent research has demonstrated how to of a revision of the Cambrian biostratigraphic scheme use geometric morphometrics in this type of research for the Holy Cross Mountains, and allows for a dis- (e.g., Nowicki and Żylińska 2019). This study follows cussion of the possible correlations. 2 JAKUB NOWICKI AND ANNA ŻYLIŃSKA GEOLOGICAL SETTING the sandstone blocks observed on the peak of the hill, at least in part the predominantly light grey sand- The entire material studied herein was collected stones were thick-bedded. The fossils occur as inter- over more than 50 years from loose sandstone blocks nal or external moulds or their imprints, and in some on the peak of the completely forested Słowiec Hill cases abundant accumulations of sub-parallel ori- in the central part of the Palaeozoic exposure of the ented (possibly bedding-parallel) voids after fossils Holy Cross Mountains (Text-fig. 1). At 433 m above occur at one end of a sandstone block. Accordingly, sea level, Słowiec Hill is one of the highest summits a high-energy environment is postulated for the of the Orłowińskie Range, lying to the north-east of deposition of the strata, based on the predominance Widełki village (Text-fig. 2), c. 12 km to the north- of coarse quartz grains, the presence of clay clasts, west of Raków village and c. 10 km to the east of poor sorting, the preservation state of the fossils (iso- Daleszyce town. The forest covering Słowiec Hill lated, crushed fragments), and the lack of trace fos- and nearby summits is protected as part of the Cisów- sils (e.g., Orłowski 1975; Masiak and Żylińska 1994; Orłowiny Landscape Park. Kowalczewski et al. 2006). A common feature of the The Cambrian succession of the Holy Cross material is simple tectonic deformation; contrary to Mountains is composed of siliciclastic facies, subdi- the statement of Orłowski (1965) that the fossils are vided into several lithostratigraphic units (Orłowski undeformed, the available material shows that most 1975, 1988). The material studied comes from the fossils are subject to notable distortion. Słowiec Sandstone Formation, a c. 100 m thick unit This part of the Palaeozoic of the Holy Cross characterised by the predominance of light grey, in Mountains is located within the Kielce Region, also places yellowish or greenish, glauconite-bearing, referred to as the Kielce Fold Zone (e.g., Konon 2008; coarse- to medium-grained, poorly sorted quartz Żelaźniewicz et al. 2011), which represents an ex- sandstones, with clay clasts up to several centimetres posed part of the sedimentary cover of the Małopolska in size (Orłowski 1975; Masiak and Żylińska 1994). Block, a crustal element within the Trans-European Coarser grains occur often as distinct intercalations Suture Zone (Berthelsen 1992). Among the dif- between the finer quartz grains. The rocks do not ferent views on the nature of this crustal block are contain any trace fossils, as opposed to the common those suggesting its proximal nature as part of the occurrence of ichnofossil assemblages in the under- Baltica palaeocontinent (e.g., Nawrocki et al. 2007; lying Ociesęki Sandstone Formation (e.g., Orłowski Żelaźniewicz et al. 2009) or its exotic provenance as a 1989, 1992b). As can be estimated from the sizes of terrane rifted from Gondwana and accreted to Baltica Text-fig. 1. Geological sketch-map of the Holy Cross Mountains (HCM) showing the distribution of Cambrian deposits, modified from Orłowski (1975, 1992a), with location of Słowiec Hill. EEC – East European Craton, TTL – Teisseyre-Tornquist Line. PARADOXIDIDS (TRILOBITA) FROM THE CAMBRIAN OF SŁOWIEC HILL 3 evaluation of their stratigraphic significance, coupled with biostratigraphic analysis of other fossils present in this locality, are the topic of this contribution. HISTORY OF RESEARCH ON THE PARADOXIDIDS FROM SŁOWIEC HILL Paradoxidids from Słowiec Hill were mentioned more than a century ago in the classical monograph on the geology of the area (Czarnocki 1919), and the attribution of this part of the Cambrian succession to the traditional Middle Cambrian was based on the presence of Paradoxides tessini Brongniart, 1822 and Paradoxides sp. Later, Czarnocki (1927a, p. 196, 1927b, p. 87, 1933, p. 81) supplied more extensive Text-fig. 2. Sketch-map of the Słowiec Hill area. faunal lists, where for the first time the endemic spe- cies ‘Paradoxides polonicus sp. n.’ and ‘Paradoxides slowiecensis sp. n.’ were mentioned, which were later formally named in Orłowski (1965). However, as is typical in Jan Czarnocki’s publications on the fos- during the Cambrian (e.g., Belka et al. 2002). Recent sils from the Holy Cross Mountains, photographs interpretations postulate that the Małopolska Massif or drawings of the specimens, or their descriptions, was not an individual terrane but part of the mar- were never published; only faunal lists and similari- gin of Baltica, despite the Amazonian provenance of ties of the fossils to those known from other regions clastic material (Walczak and Belka 2017) that could were presented in the publications mentioned above. have been supplied to lower Cambrian clastic sedi- Not much is left of Jan Czarnocki’s fossil collections, ments through the newly opening Tornquist Ocean which were decimated, burnt, and deprived of mu- (Aleksandrowski and Mazur 2017). seum labels following the Warsaw Uprising in 1944 The biostratigraphic scheme of the Cambrian in during the Second World War; their scanty remains the Holy Cross Mountains is based mainly on trilo- are presently housed in the Museum of the Polish bites, supported in some intervals by acritarch assem- Geological Institute – National Research Institute in blages (e.g., Szczepanik and Żylińska 2016; Nowicki Warsaw. A few specimens of the Cambrian trilobites and Żylińska 2019 and references therein). Members from the Holy Cross Mountains (including those of the Paradoxididae have so far been recognised in from Słowiec Hill) were offered by Jan Czarnocki the Kielce Region in the Cambrian Series 2–Miao- to the U.S. Geological Survey in the early 1930’s; lingian boundary interval of the Jugoszów-Usa rzów latex casts of these specimens with copies of museum succession and Brzechów (see Nowicki and Żylińska labels were made available to Orłowski (1965, p. 135) 2019 for a most recent taxonomic account) and in an by Allison R. (Pete) Palmer; presently these latex apparently younger interval on Słowiec Hill (Orłow- casts are in our possession. ski 1965, 1985). A few poorly preserved specimens The first person to illustrate the paradoxidids from of Paradoxides sp. as well as Ptychagnostus gibbus Słowiec Hill was Orłowski (1957). He presented pho- (Lin narsson, 1869), Peronospis fallax ( L i n n a r s s o n , tographs of three newly collected cranidia which he 1869), Solenopleura munsteri Strand, 1929, and Para- designated as ‘Paradoxides forms of the ölandicus solenopleura linnarssoni (Brøgger, 1878) have been group’; furthermore, the succession on Słowiec Hill reported from the upper Wuliuan strata of Pieprzowe was postulated to encompass strata older than consid- Mts.1 near Sandomierz town in the easternmost part ered by Czarnocki (1927a, b, 1933). In a revision of the of the Łysogóry Region (Orłowski 1964; Text-fig. 1). Słowiec Hill fauna, Orłowski (1965) provided the first Revision of the paradoxidids from Słowiec Hill and formal descriptions and illustrations of Paradoxides polonicus and Paradoxides slowiecensis, the two 1 Gürich (1892, p. 70) noted the presence of Paradoxides tessini Brongniart, 1822 from Pieprzowe Mts., but the speci- forms mentioned earlier by Czarnocki (1927a, b, men has not been recovered in museum collections so that 1933).