Isotopic time-series (δ13C and δ18O) obtained from the columnar layer of Permian brachiopod shells are a reliable archive of seasonal temperature variations

Permian brachiopods from Oman are well-known as valuable tools for correlation and palaeobiogeographical and palaeoclimatic reconstructions. Here, we describe a new brachiopod fauna from the Qarari Unit of the allochthonous Batain Group in northeast Oman. Brachiopods were collected from four localities: Wadi Khawr al Jaramah (WKJ), Jebel Qarari (JQ1), Jebel X (JX3) and Shiya (SH11). The age of the fossiliferous localities is wellconstrained to the late Kungurian-early Roadian by conodonts and fusulines, in agreement with the age suggested by the brachiopod ranges.The brachiopod fauna consists of 339 specimens belonging to 68 species of 8 orders, among which five species are here identified as new. Based on the taphonomic attributes and the analysis of the brachiopod life-styles, the assemblages from the Qarari Unit are interpreted as life assemblages thriving on varied substrates, with limited post-mortem exposure on the sea floor and rapid burial at depths around the storm wave base.Based on the generally high biodiversity indices (Shannon-Wiener and Margalef indices), the Qarari brachiopod fauna can be considered a biodiversity hotspot, only comparable, in term of biodiversity, to the coeval faunas from West Texas and South China. However, palaeobiogeographical affinities of the Qarari brachiopods with these faunas are scanty, as well as the affinities with coeval faunas from the northern Gondwana margin and the Cimmerian and Cathaysian blocks, except for some similarities with the upper Kungurian brachiopods of Myanmar. This may be explained by the fact that the Qarari succession was deposited in the Madagascan arm of Neo-Tethys, and thus rather isolated from the main Gondwanan margin.

Upper cisuralian-lower guadalupian brachiopods from the qarari unit, batain plain, northeast oman: systematics, palaeoecology and correlation

The Late Permian was a time interval characterized by extreme environmental perturbations, culminating with the Siberian Traps-related gas emissions and the subsequent global warming and ocean acidification, which produced the most severe mass extinction of the Phanerozoic (Dal Corso et al., 2022). Evidence of these perturbations are recorded in fossil archives, as pristine brachiopod shells (Garbelli et al., 2017). Here, we show shell microstructural variations and stable isotopes profiles recorded by specimens of Araxilevis intermedius (Abich, 1878), a large-sized and thick-shelled brachiopod species abundant in the Upper Permian of Iran. Nine specimens of A. intermedius were selected from several Wuchiapingian beds of the Hambast Formation in the Abadeh Section and of the Julfa Formation in the Ali Bashi Mountains Main Valley section (Iran), following the correlation by Viaretti et al. (2021). Prior to the isotope analysis different screening tests were performed on the brachiopod shells from both sections: Scanning Electron Microscope microstructural analysis, cathodoluminescence (CL) and trace elements analyses. Specimens of A. intermedius are characterized by a three-layered shell, comprising a secondary layer of cross-bladed laminae and a tertiary columnar layer; the primary layer is not preserved. The specimens from the Hambast Formation of Abadeh show a partially altered shell, whereas those from the Julfa Formation of the Ali Bashi Mountains show a well-preserved microstructure, despite CL analysis indicating that all the specimens were non-luminescent, both the microstructurally well-preserved and the altered ones. After having checked the shell preservation, 12 to 29 powder samples were collected from the longitudinal shell section of each pristine specimen of A. intermedius using a sclerochronological approach. This method allowed to investigate the seasonal environmental changes recorded by the brachiopod shells of A. intermedius from Iran and to test if this species of the Class Strophomenata, abundant in this time interval also outside Iran, can be considered a good archive for paleoclimatic and paleoenvironmental reconstructions in the Late Permian.&amp;#160;Dal Corso J., Song H., Callegaro S., Chu D., Sun Y., Hilton J., Grasby S.E., Joachimski M.M. &amp; Wignall P.B. 2022. Environmental crises at the Permian&amp;#8211;Triassic mass extinction. Nat. Rev. Earth Environ, 3, 197-214.Garbelli C., Angiolini L. &amp; Shen S.Z. 2017. Biomineralization and global change: A new perspective for understanding the end-Permian extinction. Geology, 45(1), 19-22.Viaretti M., Crippa G., Posenato R., Shen, S.Z. &amp; Angiolini L. 2021. Lopingian brachiopods from the Abadeh section (Central Iran) and their biostratigraphic implications. Boll. Soc. Paleont. It., 60(3), 213-254. 

Selecting the best brachiopod biomineral archive of the Wuchiapingian climate change

A new Mesozoic scorpion from the Besano Formation (Middle Triassic, Monte San Giorgio UNESCO WHL), Italy

Corresponding autor’s contact: marco.viaretti@studenti.unimi.it How to cite: Viaretti et al. (2020). An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study. Fossilia, Volume 2020: 53-55. https://doi.org/10.32774/ FosRepPal.2020.0614 Fossilia Reports in Palaeontology An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study

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Marco Viaretti

Papers

Upper cisuralian-lower guadalupian brachiopods from the qarari unit, batain plain, northeast oman: systematics, palaeoecology and correlation

Selecting the best brachiopod biomineral archive of the Wuchiapingian climate change

A new Mesozoic scorpion from the Besano Formation (Middle Triassic, Monte San Giorgio UNESCO WHL), Italy

An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study