Napora cristata, 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 : 60

Napora cristata n. sp. ( Fig. 28 I-K)

Napora sp. E – Pessagno et al. 1986: 46, pl. 10, fig. 18.

HOLOTYPE. — Photo No. 54928; stub 22/17; Musée de Géologie , Lausanne, No. 74414 ( Fig. 28I ).

PARATYPES. — MNHN, bât. de Géologie, No. Gg 2001/2092, Gg 2001/2094-2097.

ETYMOLOGY. — From the Latin cristatus: crested.

OCCURRENCE. — Early Tithonian ( Hybonotum Zone ) to late Tithonian (Zone 4 of Pessagno et al. 1984).

MATERIAL EXAMINED. — 10 specimens from the type horizon (sample Mue 22), one specimen from sample Mue 9.

DIMENSIONS ( IN µM). — Total length 215-265 (av. 245), length of apical horn 50-65 (av. 60), of cephalis 20-30 (av. 25), of thorax 50-65 (av. 55), of velum 60- 65 (av. 62), of feet 85-130 (av. 110); total width 125- 155 (av. 135), width of cephalis 40-50 (av. 45), of thorax 85-95 (av. 90).

DESCRIPTION

Cephalis small, imperforate and smooth, well distinguished from thorax. Apical horn long and very slightly curved ventrally, three-bladed, with a crown of three small spines at the distal part of blades. Blades unequal, the dorsal blade shorter than the two blades aligned with the primary lateral spines. Consequently the three small spines from the distal part of the blades arise at two levels, the spine on the dorsal blade is nearer to the cephalis than the other two. Apical horn pointed beyond the crown of spines. Ventral spine short externally, beak-shaped. Thorax pyramidal with four to five transversal rows of large pores. Feet slightly divergent, straight or slightly curved, often with one or two teeth on the distal part of blades. Distal part gently tapering and usually slightly recurved. Length of feet equal somehow with the height of cephalothorax or longer. Velum very delicate and short, connecting the proximal half of the inner blades of the feet.

REMARKS

Napora cristata n. sp. is quite probably the forerunner of the Cretaceous species Napora praespinifera Pessagno, 1977 . The apical horn of both species is almost identical but in N. cristata n. sp. it is shorter, thicker, and only some blades have two subsidiary spines. The thorax of this new species has also fewer and larger pores, and feet are usually slightly recurved distally and have at least one small spine on each blade. The velum is much more robust and longer in N. praespinifera and is preserved in even poorly preserved specimens, whereas in the well preserved specimens of N. cristata n. sp. it is delicate and short. Possibly the differences between these two species are only of subspecies level. Anyway, N. praespinifera , N. cristata n. sp., and Napora (Ultranapora) sp. A and sp. B of Pessagno (1977b) represent a rather closely related group of species.

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.