Richterina Gürich, 1896

Olempska, Ewa, 2002, The Late Devonian Upper Kellwasser Event and entomozoacean ostracods in the Holy Cross Mountains, Poland, Acta Palaeontologica Polonica 47 (2), pp. 247-266 : 262

Genus Richterina Gürich, 1896

Subgenus Richterina (Volkina) Rabien, 1954

Richterina (Volkina) zimmermanni ( Volk, 1939) .—This species (Fig. 9C–E) occurs in the pre−event part of the section. Its lateral outline is elongate oval, and both ends are almost equally rounded. A shallow dorsal depression is present.Themusclepitisabsent.Thesurfacebears30–35narrow longitudinalribsofequalstrength.Ribsareconcentricallyarrangedaroundtheanteriormargin.Intheposteriorpartofthe carapace,twoorthreeinnerdorsalribsusuallyjointhecorrespondingventralribsatanacuteangle.Outerdorsalandventral ribs are almost parallel to the margins. In poorly preservedspecimenswithaninvisiblemusclepit,itisdifficultto distinguish between R. (V.) zimmermanni and N. pseudorichterina .

Range and occurrence.—This species is known from the middle and late Frasnian, W. cicatricosa Zone up to the E. (E.) splendens Zone, of Europe (Rhenish Slate Mts., Harz Mts., Thuringia, Spain, Montagne Noire, Ardennes, Holy Cross Mts.), N−Africa (Sahara, Algeria), N−America (Ohio) and South China. However, in China it occurs also in the early Famennian, F. (F.) sigmoidale Zone.

Richterina (Volkina) latecostata Rabien, 1954 .—This rare species ( Fig. 11 ) is restricted to the middle part of the Płucki section (sample P−69). Its lateral outline is elongately oval, the dorsal margin is gently curved, and the ventral margin is more curved. The anterior and posterior ends are rather narrowly and equally rounded. The surface bears six to seven longitudinal ribs separated by wide intercostal grooves. In thedorsalpartofthecarapace,ribsarealmoststraight,andin theventralpart,theyaremorestronglycurved.Afewintercalated ribs are present.

Range and occurrence.—Thisspeciesisknownfromthelatest Frasnian, E. (E.) splendens Zone, of Europe.

Figures

Fig. 11. Schematic drawing of Richterina (Volkina) latecostata Rabien, 1954. Sample P−69.