Napora aranea, Dumitrica & Zügel, 2003

Dumitrica, Paulian & Zügel, Peter, 2003, Lower Tithonian mono- and dicyrtid Nassellaria (Radiolaria) from the Solnhofen area (southern Germany), Geodiversitas 25 (1), pp. 5-72 : 57-58

Napora aranea n. sp. ( Fig. 28A, B )

HOLOTYPE. — Photo No. 42556; stub Mue 22/11; Musée de Géologie , Lausanne, No. 74411 ( Fig. 28A ). ETYMOLOGY. — From the Latin aranea : spider, spider’s web.

MATERIAL EXAMINED. — Eight specimens from the type horizon (sample Mue 22).

DIMENSIONS ( IN µM). — Total length 400-570 (av. 480), length of apical horn with the crown of spines 120-185 (av. 160), of cephalis 30-35 (av. 32), of thorax 100-110 (av. 105), of velum 65-90 (av. 75), of feet 150-255, width of cephalis 42-50 (av. 45), of thorax 115-165 (av. 145).

DESCRIPTION

Cephalis small, globular to hemispherical with pustulate surface. Apical horn three-bladed with two to three verticils of three branches in the planes of blades. Branches strongly ramified usually in the planes of blades, and connected in the same planes by a system of parallel or subparallel bars forming a network resembling a spider’s web. Ventral spine very short externally, bladed, pyramidal. Collar suture well marked outside by a slight constriction and the absence of pustules. Thorax bell-shaped, slightly constricted distally, approximately three times the width of the cephalis. Pores small, usually irregularly arranged on the proximal part, and larger, arranged in transverse rows on the distal part. Transverse rows separated by more or less distinct transverse ridges. Surface of thorax rough, with small thorns on pore frame vertices. Feet long, three-bladed, straight or slightly curved outward or inward. Velum thin, delicate, as long as or shorter than thorax. It is triangular in cross section, usually with quadrangular pores disposed in transverse rows between transverse ridges.

REMARKS

Napora aranea n. sp. differs from all the species of Napora so far known by its branched, spider’s web-shaped apical horn. An apical horn somehow similar has the Albian-Turonian species Napora spinifera ( Pessagno 1977b) , but this species has shorter subsidiary spines on the distal part of the horn and does not develop spider’s web branches.

Figures

FIG. 28. — A, B, Napora aranea n. sp.; A, holotype, view from Ll; B, paratype, dorsal view; C-E, Napora avirostrum n. sp.; C, holotype, view from Lr; D, E, paratypes; D, dorsal view; E, view from Lr; F, G, Napora bondoca n. sp.; F, holotype, view from Ll; G, paratype, view from Ll; H, Napora burckhardti Pessagno, Whalen & Yeh, 1986, dorsal view; I-K, Napora cristata n. sp.; I, holotype, right lateral view; J, K, paratypes; J, right lateral view; K, view from Ll; L, M, Napora divaricata n. sp., holotype, ventral and basal views. Abbreviations: Ll, left primary lateral spine; Lr, right primary lateral spine. Scale bars: A-E, H, K, 100 µm; F, G, I, J, L, M, 30 µm.