Canoptum rarum Tekin, 2020

Tekin, Kagan, Krystyn, Leopold, Okuyucu, Cengiz, Bedi, Yavuz & Sayit, Kaan, 2020, 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, Geodiversitas 42 (27), pp. 493-537 : 524

Canoptum rarum Tekin , n. sp.

( Fig. 11 V-X)

urn:lsid:zoobank.org:act:D8026B8E-0D55-4575-9022-E9AB66091477

HOLOTYPE. — Sample Orbuk-15, HU.JMB.0154 ( Fig. 11V ).

PARATYPES. — HU.JMB.0155 ( Fig. 11W ), HU.JMB156 ( Fig. 11X ).

TYPE LOCALITY. — Orbuklukeli section, Mersin Mélange, NW of Mersin city, southern Turkey.

ETYMOLOGY. — From the Latin rarum , rare, due to its rare occurrence.

OCCURRENCE. — Upper Triassic, Rhaetian, Orbuklukeli section, Mersin Mélange, NW of Mersin city, southern Turkey.

DIMENSIONS (based on three specimens, in µm). — Maximum length of test: 200-220 (holotype: 208, average: 209.3); Maximum width of test: 104-120 (holotype: 104, average: 111.3).

DESCRIPTION

Test spindle-shaped, multicyrtid with six post-abdominal segments. Test increasing in width gradually up to the third post-abdominal segment, then the last three segments are decreasing in width. Cephalothorax hemisphaerical, mainly poreless. Abdomen to third post-abdominal segment hooplike and strictures between these segments less-prominent, marked only by very shallow depressions. Strictures between third to sixth post-abdominal segments not visible. Because of dense silica accumulation, only small scattered pores are visible on the surface of test. When accumulation of silica is not prominent, two rows of pores can be seen around strictures. On wider part of test, corresponding to the third postabdominal segment, 16 pores are visible in one row.

REMARKS

This taxon can be differentiated from other species of the genus Canoptum Pessagno by having the spindle-shaped last three segments without superficial strictures.

Figures

FIG. 11. — Photomicrographs of the radiolarians from the Orbuklukeli section; A, B, Droltus sp. aff. D. eurasiaticus Kozur & Mostler, 1990, Orbuk-32; C, Droltus hecatensis Pessagno & Whalen, 1982, Orbuk-32; D-F, Droltus laseekensis Pessagno & Whalen, 1982, Orbuk-27; G-J, Trexus dodgensis Whalen & Carter in Carter, Whalen & Guex, 1998; G-H, Orbuk-27; I, J, Orbuk-32; K-O, Canoptum cephalobulbosum Tekin, n. sp.; K, Holotype, Orbuk-15; L-O, Paratypes, Orbuk-15; P, Canoptum columbiaense Whalen & Carter in Carter, Whalen & Guex, 1998, Orbuk-27; Q, Canoptum merum Pessagno & Whalen, 1982, Orbuk-15; R-U, Canoptum productum Tekin, n. sp.; R, Holotype, Orbuk-15; S-U, Paratypes, Orbuk-15; V-X, Canoptum rarum Tekin, n. sp.; V, Holotype, Orbuk-15; W-X, Paratypes, Orbuk-15. Scale bar: A, B, 200 µm; C, P, 120 µm; D-J, 100 µm; K-O, R-X, 80 µm.