Acrotheloidea Walcott, 1908

Holmer, Lars E. & Biernat, Gertruda, 2002, Urban and Peri-urban small and medium-size Enterprise Development for sustainable Vegetable Production and Marketing Systems, Acta Palaeontologica Polonica 47 (1), pp. 141-156 : 145-146

Superfamily Acrotheloidea Walcott and

Schuchert, 1908 (in Walcott 1908)

Family Acrothelidae Walcott and Schuchert, 1908

(in Walcott 1908)

Subfamily Acrothelinae Walcott and Schuchert, 1908

(in Walcott 1908)

Genus Orbithele Sdzuy, 1955

Type species: Discina contraria Barrande, 1868 ; Ordovician Leimitz Shale (Tremadoc?); Bavaria.

Orbithele ceratopygarum Brøgger, 1882 Fig. 1P–R .

Discina ( Acrotreta ?) ceratopygarum Brøgger, 1882: 47 , pl. 10: 1–1b.

Orbithele bicornis sp. nov.; Biernat 1973: 101, pl. 27: 1–3, fig. 27.

Orbithele ceratopygarum (Brøgger) ; Popov and Holmer 1994: 146, figs 113–115. [full synonymy]

Orbithele ceratopygarum (Brøgger) ; Holmer, Popov, and Bassett 2000: 372, fig. 4A–G.

Material.—Total of 3 ventral valves. Figured ventral valves: RM Br133765, RM Br133766.

Diagnosis.—See Popov and Holmer (1994: 146).

Remarks.—A full comparative discussion of this widespread species was given by Popov and Holmer (1994). Recently Holmer et al. (2000) also described O. ceratopygarum from the Early Ordovician (early Arenig) of Kirgizia. The available specimens from the Holy Cross Mountains show no differences from the Norwegian and Swedish specimens; however, the dorsal valve of the Polish form is unknown.

Figures

Fig. 1. A–L. Leptembolon cf. lingulaeformis (Mickwitz). A, E. Ventral valve RM Br133755, interior (A, × 18) and oblique lateral view of interior (E, × 32). B. Ventral valve RM Br133756, exterior; × 23. C, G, J. Ventral valve RM Br133757, interior (C, × 15), oblique lateral view (G, × 23) and detail of pseudointerarea (J, × 54). D, I. Dorsal valve RM Br133758, oblique lateral view of interior (D, × 30) and detail of pseudointerarea (I, × 46). E. Ventral valve RM Br133759, oblique lateral view of exterior; × 30. H. Dorsal valve RM Br133760, oblique lateral view of interior; × 26. K. Ventral valve RM Br133761, interior; × 37. L. Ventral valve RM Br133762, oblique lateral view of umbo; × 92. M–O. Rowellella sp. M. Dorsal valve RM Br133763, oblique lateral view of juvenile dorsal valve; × 41. N, O. Indeterminate valve RM Br133764, oblique lateral view (N, × 84) and detail of ornamentation (O, × 110). P–R. Orbithele ceratopygarum (Brøgger). P, Q. Ventral valve RM Br133765, exterior (P, × 37) and detail of larval shell (Q, × 100). R. Ventral valve RM Br133766, oblique lateral view of ventral valve exterior; × 80. All specimens from the Tremadoc chalcedonites, Wysoczki.