Pleuroctenium


Pleuroctenium is an agnostid trilobite belonging to the family Condylopygidae Raymond. The genus occurs in Middle Cambrian strata of Canada, the Czech Republic, England and Wales, France, and Sweden.

Type species

By subsequent designation by Vogdes
Battus granulatus Barrande, 1846, p. 15., from the Middle Cambrian of Bohemia.
Lectotype: By subsequent designation by Snajdr, National Museum of Prague, coll. Barrande, cc 250, No.1008; figured Barrande ; Šnadjr ; and Horny & Bastl, 1970, p1. 1, fig. 6. From the Skryje Beds, Eccaparadoxides pusillus Zone, Týřovice, Bohemia.

Distribution

  • P. granulatum granulatum Barrande has been collected from the early Middle Cambrian of Canada, the Czech Republic, the "Paradoxides aurora" Zone to upper part of the Mawddachites hicksi Zone in the Abbey Shale Formation, Nuneaton, central England and from lower part of the Tomagnostus fissus Biozone within the Porth-y-rhaw Group, lower Menevia Formation of Dwrhyd, Nine Wells, near St David's, SW Wales. The Whitesands Bay Formation of Rees et al,. is conventionally referred to the biozone of "Paradoxides aurora" Salter, following Hicks. However, that species is a probable junior subjective synonym of Mawddachites hicksii, and so no independent aurora Biozone can be recognized.
  • P. granulatum scanense Westergard, 1946. The holotype cephalon was figured by Westergard. The subspecies is also recorded from the Menevia Formation of Porth-y-rhaw, St David's Peninsula, SW Wales, Locs. OE-1 and PR-4 of Rees et al.,.
  • P. granulatum tuberculatum. The lectotype, SM A53055, is the specimen shown in Illing's fig. 7 of pl.33; selected and re-illustrated by Rushton ; from the Abbey Shale Formation, Hartshill Hayes, Nuneaton, T. fissus Biozone. Also recorded from the H. parvifrons Biozone, Menevia Formation in SW Wales, Loc PR-4 of Rees et al., and from the Mawddachites hicksii Zone and lower part of the P. davidis Zone in the Manuels River Formation of southeastern Newfoundland.
  • P. granulatum pileatum, from the Purley Shale, Accadoparadoxides? pinus Zone, of Camp Hill, Stockingford, Nuneaton, Warwickshire, England. .
  • P. bifurcatum. Lectotype is SM A456, Illing's fig.2 of pl.33; selected and re-illustrated by Rushton and from the Ptychagnostus punctuosus Biozone, Abbey Shale Formation, Hartshill Hayes. The species occurs also in the Manuels River Formation of SE Newfoundland, uppermost part of the Paradoxides davidis Zone. P. cf. bifurcatum is recorded from the Menevia Formation of Porth-y-rhaw, SW Wales, Pt. punctuosus Biozone, and differs from bifurcatum in lacking the double row of three tubercles on the pygidium. Rushton also mentioned a doubtful pygidium from Illing's Abbey Shales horizon G1, lowest horizon of the Pt. punctuosus Biozone at Nuneaton, which lacks the double row of tubercles on the axis, but which otherwise agrees with that of P. bifurcatum.
  • P. magnificum Howell is from the Middle Cambrian of Hérault, Southern France.