Napora Pessagno, 1977

Dumitrica, Paulian & Zügel, Peter, 2003, Lower Tithonian mono- and dicyrtid Nassellaria (Radiolaria) from the Solnhofen area (southern Germany), Geodiversitas 25 (1), pp. 5-72 : 57

Genus Napora Pessagno, 1977

Napora Pessagno, 1977a: 94 .

Jacus De Wever, 1982: 204 ; type species: Jacus coronatus De Wever, 1982 .

TYPE SPECIES. — Napora bukryi Pessagno, 1977 ; original designation.

RANGE. — Lower Jurassic to Upper Cretaceous.

REMARKS

The study of the initial spicule of the species Napora modesta n. sp. in transmitted light showed that the cephalic initial skeleton consists of MB, V, A, two L, two l, D, and the arches VL, Ll, lD, Al. The arch AV is absent, but an arch AD seems to exist because one of the three blades of the apical horn has a dorsal direction.

Genus Jacus De Wever, 1982 is herein considered a junior synonym of Napora . The differences between these two genera concern only the superficial structure of thorax, a character that can be considered of specific level. The absence of the cephalocone, considered by De Wever (1982) an additional distinctive character from Napora , has no value because in both genera it is nothing else than the short ventral spine. Moreover, both genera have the apical horn with a verticil of three spines or spinules as extensions of the three blades; exceptions are very rare. This is also a character that differentiates Napora and Jacus from Anaticapitula n. gen.

Members of the genus Napora are among the most frequent dicyrtid nassellarians in the lower Tithonian radiolarian assemblage studied in the present article, although some species are very rare.