Takoum takemurai, 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 : 34

Takoum takemurai n. sp. ( Fig. 19 A-F)

HOLOTYPE. — Photo No. 58132-58134; stub Mue 22/20; Musée de Géologie , Lausanne, No. 74393 ( Fig. 19 A-C).

ETYMOLOGY. — The species is named for Dr. Atsushi Takemura, to honour his contribution to the knowledge of the initial structures of many Jurassic nassellarians.

MATERIAL EXAMINED. — 15 specimens from the type horizon (sample Mue 22).

DIMENSIONS ( IN µM). — Length of cephalis 42-51 (av. 48), of apical horn 26-32 (av. 29), of dorsal spine 33-60, of primary lateral spines 35-95 (av. 60), of secondary lateral spines 35-47 (av. 39), width of cephalis 52-65 (av. 59).

DESCRIPTION

Cephalis small, hemispherical, low, with rounded pores of various arrangement and size, decreasing generally in size apically. Surface of cephalis rough due to some small thorns. Apical horn, dorsal spine, primary and secondary lateral spines long, straight, three-bladed proximally, circular in cross section medially and distally. Sometimes they are covered by very tiny thorns. Dorsal, secondary and primary lateral spines extended laterally. Ventral spine very short, hardly extended outside shell wall, directed obliquely upward. Arches Al, Dl, Ll and LV well marked, whereas arch AV seems to be missing.

REMARKS

Takoum takemurai n. sp. has the initial cephalic structure of T. hexagonum type but differs from this species in having a very short cephalis. The cephalis of T. hexagonum is very high, wider apically than basally, and the ventral spine is as long as the other spines.

Figures

FIG. 19. — A-F, Takoum takemurai n. sp.; A-C, holotype, right lateral and basal views, and details of the initial spicule and arches; D-F, paratype, partly broken but with some spines completely preserved, left lateral, dorsal and basal views; G-J, Tripedocorbis tardus n. sp.; G, H, holotype, left lateral and basal views respectively with details of the initial spicule and arches; I, J, paratype, dorsal and basal views. Scale bars: 30 µm.