Late Triassic to Early Jurassic radiolarian, conodont and ammonite assemblages from the Tavuscayiri block, Mersin Mélange, southern Turkey: Time constraints for the T / J boundary and sedimentary evolution of the southern margin of the northern Neotethys Author Tekin, Kagan Author Krystyn, Leopold Author Okuyucu, Cengiz Author Bedi, Yavuz Author Sayit, Kaan text Geodiversitas 2020 2020-11-26 42 27 493 537 journal article 10.5252/geodiversitas2020v42a27 20141273-3452-4388-b6a8-aab9193c87fe 1638-9395 4447758 urn:lsid:zoobank.org:pub:1A437774-B5BE-49F2-8DEF-D46F2790484A Stauroacanthocircus sp. A ( Fig. 10R ) OCCURRENCE. — Lower Jurassic, lower Sinemurian of Mersin Mélange, NW of Mersin city, southern Turkey . DESCRIPTION Shell not preserved, ring broad and elliptical. Thin ring contains eight, thin, needle-like spines. Inner cavity broad, elliptical with four thin polar spines. REMARKS This specimen differs from Stauroacanthocircus dickinsoni ( Yeh 1989: 50 , pl. 13, fig. 18) by having a broad elliptical ring and inner cavity, and thin, short peripheral and polar spines.