Xiphachistrella Deflandre, 1973

Noble, Paula, Aitchison, Jonathan C., Danelian, Taniel, Dumitrica, Paulian, Maletz, Jörg, Suzuki, Noritoshi, Cuvelier, Jessie, Caridroit, Martial & O’Dogherty, Luis, 2017, Taxonomy of Paleozoic radiolarian genera, Geodiversitas 39 (3), pp. 419-502 : 427

Xiphachistrella Deflandre, 1973

Xiphachistrella Deflandre, 1973b: 499 ; 1960: pl. 1, fig. 25 (nomen nudum).

TYPE SPECIES. — Xiphachistrella acipensis Deflandre, 1973 ( Deflandre 1960: pl.I, fig. 25 [nomen nudum]), described in Deflandre (1973a: 292, pl. 4, fig. 4-7x).

AGE AND LOCATION OF TYPE MATERIAL. — Lower Carboniferous, France.

TAXON CODE. — 028.

STATUS. —Junior synonym of Ceratoikiscum Deflandre, 1953 (herein).

DIAGNOSIS. — “Squelette muni d’un gros spicule droit, tricostulé dans sa partie supérieure qui est en forme de poignard et se rétrécit brusquement en un point d’où partent des arcs régulièrement courbés, assez larges, un peu plus petits que des quarts de cercles et se terminant en donnant naissance à une forte épine perpendiculaire et dirigée vers le haut; à ces formations se joignent d’autres arcs, minces, dirigés vers la partie inférieure et pouvant la rejoindre, arcs très partiellement conservés. Partie médiane du spicule axial oblitérée et non-descriptible. Partie inférieure portant quatre cornes divergentes, droites, pointues, formant un angle d’environ 65°, reliées entre elles par de très fines trabécules transversales plus ou moins obliques.” ( Deflandre 1973b: 499).

DIAGNOSIS (English translation by Taniel Danelian). — “Skeleton bearing a large straight spicule, tricostulate in its upper part which has the form of a dagger and suddenly shrinks to a point from which regularly curved wide arches a little less than complete circles and quarters end giving rise to a strong upwards directed perpendicular spine; these join other arches, slender, directed to the bottom which may join, partially preserved arches. Mid-section of the axial spike is obliterated and not describable. Lower part with four diverging horns, straight, pointed, forming an angle of about 65°, connected by very fine, more or less oblique transverse trabeculae.”

REMARKS

Re-examination of slides BD54, R45/3 and BD 82, G37/4 of Deflandre’s collection by Martial Caridroit indicates that Xiphachistrella acipiens is a junior synonym of Ceratoikiscum because both share the characteristic initial triangle. Note also that the type species is described in Deflandre (1973a: 292) but Deflandre’s genus description appears later ( Deflandre 1973b: 499).