Canoptum cephalobulbosum 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 : 522

Canoptum cephalobulbosum Tekin , n. sp. ( Fig. 11 K-O)

urn:lsid:zoobank.org:act:E28BC50B-39C6-4959-B646-EB90ABB2B414

HOLOTYPE. — Sample Orbuk-15, HU.JMB.0145 ( Fig. 11K ).

PARATYPES. — HU.JMB.0146 ( Fig. 11L ), HU.JMB.0147 ( Fig.11M ), HU.JMB.0148 ( Fig. 11N ), HU.JMB.0149 ( Fig. 11O ).

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

ETYMOLOGY. — Due to its very bulbose cephalis.

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

DIMENSIONS (based on five specimens, in µm). — Maximum length of test: 144-160 (holotype: 144, average: 151.4); Maximum width of test: 80-96 (holotype: 96, average: 90.4).

DESCRIPTION

Test mainly conical with three to four post-abdominal segments, increasing in width until second post-abdominal segment, then last two post-abdominal segments decreasing in width. Cephalis knob-like, bulbous, poreless without horn. Collar stricture mainly poreless and marked by a shallow depression. Test increasing in width slowly until the second post-abdominal segment and subtrapezoidal to hoop-shaped in outline while last two segments decreasing in width, and inverse subtrapezoidal to hoop-shaped in outline. Thorax mainly covered by veneer of microgranular silica but sometimes including some subcircular scattered pores. In some specimens ( Fig. 11K, O ), small nodes are also visible at the surface of thorax. Abdomen and post-abdominal segments with small, numerous, circular to subcircular pores. In some specimens ( Fig. 11K, M ), where veneer of microgranular silica is not prominent, two rows of pores are visible just below and above the circumferential strictures.

REMARKS

This species differs from Canoptum rhaeticum ( Kozur & Mostler 1981: 103-104, pl. 20, figs 1-4) by having a very bulbous cephalis, shorter and slimmer test composed of less segments.

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.