An unusual occurrence of the Laurentian phyllocarid crustacean Ceratiocaris papilio Salter in the lower Ludfordian (Silurian) of Bohemia (peri-Gondwana)

Abstract

A rich assemblage (n = 223) of well-preserved phyllocarid crustacean remains is described from offshore calcareous shales of the Kopanina Formation (Silurian, Ludlow, early Ludfordian, Saetograptus linearis Biozone) exposed near the village of Všeradice, SE of Beroun. Specimens examined fall within the intraspecific variability of Ceratiocaris papilio Salter in Murchison, 1859, which is widely distributed in the Llandovery and Wenlock of Laurentia. Consequently, the Bohemian specimens represent the first occurrence of C. papilio outside of Laurentia. Additionally, the phyllocarid as-semblage from Bohemia is younger than that of Laurentia. In Bohemia, Ceratiocaris papilio occurs in finely laminated calcareous shales. Its abundance varies distinctly from bed to bed, and phyllocarids are the dominant faunal component in only a few beds. Phyllocarids are associated with common graptolites and pelagic orthocerids while other benthic or-ganisms are severely limited. Isolated or articulated furcae and telsons, and isolated mandibles are the most common components of this association, but articulated abdominal segments with caudal appendages (but without carapaces) also occur. An exceptional, slightly disarticulated specimen has articulated abdominal and partial thoracic segments, with mandibles preserved in situ. Additional possible occurrences of C. papilio and related species in Bohemia are also discussed.