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 8503 10.5252/geodiversitas2020v42a27 20141273-3452-4388-b6a8-aab9193c87fe 1638-9395 4447758 urn:lsid:zoobank.org:pub:1A437774-B5BE-49F2-8DEF-D46F2790484A Atalantria sp. A ( Fig. 12O ) OCCURRENCE. — Lower Jurassic, lower Sinemurian of Mersin Mélange, NW of Mersin city, southern Turkey . DESCRIPTION Test multicyrtid, increasing in width distally except the last segment. Last segment decreasing in width. Cephalis hemisphaerical, poreless with small, rudimentary, needle-like horn. Thorax to rest of segments, except the last one, subtrapezoidal. Last segment inverse subtrapezoidal in outline. Segments have two transverse rows of pores with hexagonal pore frames. REMARKS This specimen differs from Atalantria emmela ( Cordey & Carter 1996: 67 , pl. 24, fig. 13) by having a distally constricted test. It can be differentiated also from Atalantria epaphrodita ( Cordey & Carter 1996: 446 , pl. 1, figs 6, 7, 10, 11) by having a shorter test and cephalis with unbranched, needle-like horn.