University of Isfahan Journal of Stratigraphy and Sedimentology Researches 2008-7888 41 4 2025 12 22 Decapod crustacean from the Qom Formation (Lower Miocene) of the Isfahan area, Central Iran Decapod crustacean from the Qom Formation (Lower Miocene) of the Isfahan area, Central Iran 17 26 29582 10.22108/jssr.2025.145216.1313 FA Ali Bahrami Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Álex Ossó Ateneu de Natura, Llorenç de Villalonga, 17B, 1-1, 43007 Tarragona, Catalonia Mehdi Yazdi Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Hossein Vaziri-Moghaddam Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Azizollah Taheri Department of Geology, Faculty of Earth Science, Shahrood University of Technology, Shahrood, Iran Amir-Hossein Alibeigi Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Journal Article 2025 05 10 The discovery of a new specimen of Portunus withersi (Glaessner 1933) from the Lower Miocene Qom Formation in the Vartun section, north of Isfahan (Central Iran), contributes to our knowledge of this portunid species, to which most fossil portunids found in the Miocene of Iran have been attributed. New images of the holotype are also presented herein. The Miocene decapod fauna of Iran, exhibiting a clear Indo-Pacific affinity, reflects an emerging loss of faunal homogeneity between the decapod communities on either side of the Tethys Realm. This differentiation is related to the progressive closure of the Tethys Seaway, which interrupted the connection between the proto-Mediterranean and Paratethys seas and the Indian Ocean. This stands in contrast to the relative faunal homogeneity observed during the Paleogene, as evidenced by the presence—on both sides of the Tethys Realm—of genera such as Zanthopsis M’Coy 1849, Palaeocarpilius A. Milne-Edwards 1862, or Lophoranina Fabiani 1910, among others, and even species such as Retrocypoda almelai Vía Boada 1959. The discovery of a new specimen of Portunus withersi (Glaessner 1933) from the Lower Miocene Qom Formation in the Vartun section, north of Isfahan (Central Iran), contributes to our knowledge of this portunid species, to which most fossil portunids found in the Miocene of Iran have been attributed. New images of the holotype are also presented herein. The Miocene decapod fauna of Iran, exhibiting a clear Indo-Pacific affinity, reflects an emerging loss of faunal homogeneity between the decapod communities on either side of the Tethys Realm. This differentiation is related to the progressive closure of the Tethys Seaway, which interrupted the connection between the proto-Mediterranean and Paratethys seas and the Indian Ocean. This stands in contrast to the relative faunal homogeneity observed during the Paleogene, as evidenced by the presence—on both sides of the Tethys Realm—of genera such as Zanthopsis M’Coy 1849, Palaeocarpilius A. Milne-Edwards 1862, or Lophoranina Fabiani 1910, among others, and even species such as Retrocypoda almelai Vía Boada 1959.

https://jssr.ui.ac.ir/article_29582_2596e90aaa4baeef3f4414793f868c43.pdf