Franklinella Stewart and Hendrix, 1945

Genus Franklinella Stewart and Hendrix, 1945 View in CoL

Franklinella ( Franklinella) sigmoidale Müller−Steffen, 1964 . —This species ( Fig. 12A–E View Fig ) is abundant in the post−event partofthePłuckisection(samplesP−138toP−166).Itslateral outline is subquadrate, and the dorsal margin is long and straight.Theposteriorendismorenarrowlyroundedthanthe anterior end, and the ventral margin is gently curved. The sulcusisnarrowandextendsfromthedorsalmargintobelow the mid−height. In the posterodorsal part of the carapace, a small,conicalspine,directedslightlyoutwardsandupwards, occurs. Asimilar but larger spine occurs in the anteroventral partofthecarapace.Thesurfacebearseighttotenlongitudinal narrow ribs with wide intercostal spaces, which run at a slight angle to the dorsal margin and tend to converge towards the spines. Some intercalated ribs are also present. Threeribsareconcentricandparalleltotheposteriormargin and two are parallel to the anterior margin.

Range and occurrence.—This species occurs in the early Famennian, F. ( F.) sigmoidale Zone , of Europe (Rhenish Slate Mts., Harz Mts., Holy Cross Mts.) and South China. However in South China it is also noted from the Early R. serratostriata – N. nehdensis Zone.

Franklinella ( Franklinella) cf. calcarata ( Richter, 1856) .— This rare and small (up to 1 mm long) species (Fig. 9G) has beenfoundinsamplesP−13andP−17.Thesurfacebearsfive longitudinal ribs with wide intercostal spaces. Small spines arepresentintheposterodorsalandtheanteroventralpartsof thecarapace,theanteroventralspinesarebrokeninallspecimens. The sulcus is very poorly developed.

Range and occurrence.—This species is known from the middle and late Frasnian, W. cicatricosa Zone up to E. ( E.) splendens Zone , of Europe and South China. However it is also noted from the early Famennian, F. ( F.) sigmoidale Zone.