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 Pantanellium giganteum Tekin , n. sp. ( Fig. 6 K-O) urn:lsid:zoobank.org:act: 5BAC0A8A-3218-48FA-8EB3-E2EEF99333A4 HOLOTYPE . — Sample Orbuk-26, HU.JMB.0106 ( Fig. 6K ). PARATYPES . — HU.JMB.0107 ( Fig. 6L ), HU.JMB.0108 ( Fig. 6M ). HU.JMB.0109 ( Fig. 6N ), HU.JMB.0110 ( Fig. 6O ). TYPE LOCALITY . — Orbuklukeli section, Mersin Mélange, NW of Mersin city, southern Turkey . ETYMOLOGY. — From the Latin giganteum , giant, due to its big size. OCCURRENCE. — Lower Jurassic, upper Hettangian-lower Pliensbachian of the Orbuklukeli section, Mersin Mélange, NW of Mersin city, southern Turkey . DIMENSIONS (basedonfivespecimens,inµm). — Diameterofthecortical shell along spines: 83-120 ( holotype : 120, average: 110.5); Diameter of the cortical shell perpendicular to spines: 110-133 ( holotype : 110, average:117.1); Length of shorter spine: 50-90 ( holotype :80, average: 74.6); Length of longer spine: 120-166 ( holotype : 140, average: 147). DESCRIPTION Cortical shell large, sphaerical to subsphaerical with large pentagonal and hexagonal pore frames. Pore frames with rounded to subrounded nodes at pore frame vertices. Six to seven pore frames visible both along primary spines and perpendicular to primary spines. Polar spines unequal, three-bladed with rounded, longitudinal ridges and relatively narrow grooves. One polar spine about twice longer than the other polar spine and longer polar spine slightly dextrally twisted. REMARKS This species differs from P. freboldi ( Carter et al. 1998: 48 , pl. 1, figs 17, 21, 27) by having unequal and slightly dextrally twisted polar spines. It differs also from P. sixi Whalen & Carter in Carter, Whalen & Guex, 1998 ( Carter et al. 1998: 48 ) by possessing a larger cortical shell and longer, slightly dextrally twisted polar spines in many cases.