Laxtorum obscurum 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 : 525

Laxtorum obscurum Tekin , n. sp.

( Fig. 12K, L )

urn:lsid:zoobank.org:act:C977E9D3-0777-4F5E-9E55-1DB51E89B925

Laxtorum sp. A – Tekin 2002a: 194, 196, pl. 5, fig. 15.

HOLOTYPE. — Sample Orbuk-27, HU.JMB.0162 ( Fig. 12K ).

PARATYPE. — HU.JMB.0163 ( Fig. 12L ).

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

ETYMOLOGY. — From the Latin obscurum , obscure, indistinct, due to its obscure inner structure of test.

OCCURRENCE. — Lower Jurassic, lower Sinemurian of Antalya Nappes, NE of Antalya City and Orbuklukeli section, Mersin Mélange, NW of Mersin city, southern Turkey.

DIMENSIONS (based on two specimens, in µm). — Length of horn: 65-70 (holotype: 70, average: 67.5); Maximum length of test: 150- 160 (holotype: 150, average: 155); Maximum width of test: 90-100 (holotype: 90, average: 95).

DESCRIPTION

Test long, increasing in width gradually to the distal end, conical with four to five post-abdominal segments. Cephalis hemisphaerical with stout, needle-like and pointed apical horn. Thorax and rest of segments subtrapezoidal in outline. Strictures invisible at the surface of test. Surface of the test covered with thick silica layers. Cephalis and thorax with very rare pores, abdomen and the rest of test with large, subcircular to ellipsoidal pores and very rough surface.

REMARKS

This species has been compared to Laxtorum breve Tekin , n. sp. under the latter taxon. It can be differentiated from Laxtorum hemingense Whalen & Carter in Carter et al. (1998: 80 , pl. 25, figs 6-8, 13, 14, 24, 25; pl. 27, figs 5, 6, 16, 20) by having a test with a stout horn and indistinct circumferential ridges.

Figures

FIG. 12. — Photomicrographs of the radiolarians from the Orbuklukeli section; A, B, Canoptum rhaeticum Kozur & Mostler,1981, Orbuk-15;C, Canoptum striatum (Kozur & Mostler, 1990), Orbuk-27; D-J, Laxtorum breve Tekin, n. sp.; D, Holotype, Orbuk-32; E-J, Paratypes, Orbuk-32; K-L, Laxtorum obscurum Tekin, n. sp., K, Holotype, Orbuk-27; L, Paratype, Orbuk-27; M-N, Atalantria emmela (Cordey & Carter, 1996), Orbuk-32; O, Atalantria sp. A, Orbuk-27; P-Q, Pseudoeucyrtis