Cupitheca Duan, 1984

Malinky, John M. & Skovsted, Christian B., 2004, Hyoliths and small shelly fossils from the Lower Cambrian of North-East Greenland, Acta Palaeontologica Polonica 49 (4), pp. 551-578 : 568-569

Genus Cupitheca Duan in Xing et al., 1984

Type species: Paragloborilus mirus He in Qian, 1977, Lower Cambrian , South China .

Diagnosis.—Conch straight or curved, with circular to oval cross−section, low angle of divergence. Older parts of conch successively aborted during ontogeny in connection with formation of secondary transverse wall sealing off apical end. Operculum, if present, a simple disc (from Bengtson 1990b).

Remarks.— Demidenko (2001: 97) pointed out that the generic name Actinotheca Xiao and Zhou, 1984 used earlier ( Bengtson 1990b) for decollating, hyolith−like tubular fossils from the Lower Cambrian is occupied by a genus of tabulate corals ( Actinotheca Frech, 1884 ), and should be replaced by the next valid junior synonym, Cupitheca Duan in Xing et al., 1984 ( Cupittheca of Demidenko 2001: 96). The generic name was spelled “ Cupittheca ” by Duan (in Xing et al. 1984: 152) but this appears to be a printing error (see Wrona 2003: 200). Specimens from North−East Greenland are assigned to this genus based on the tubular conch with an apical termination created by a septum and the transverse sculpture on the shell. Bengtson (1990b) pointed out that species of this genus may be difficult to distinguish from one another, including the type species, because the type and several other species are founded upon internal moulds in which surface sculpture is lacking. Surface ornamentation, however, is considered to be a distinguishing feature of some species, including C. hemicyclata and C. holocyclata herein.

The biology of this organism, particularly as related to the development of septae and decollation of the conch was discussed by Bengtson (1990b). Owing to the separation of the apical region from the remainder of the conch as the animal grew, fragments of this taxon are common but complete specimens are rare. Affinity between North−East Greenland and Australian Lower Cambrian assemblages of shelly fossils is strongly supported by the occurrence of Cupitheca in both regions, although a third Australian species of this genus, C. clathrata ( Bengtson, 1990b) has yet to be identified from Greenland. Cupitheca is very widespread in the Early Cambrian, and ranges into the lower Middle Cambrian of Morocco and possibly England as well ( Cephalopyge notabilis Zone of Morocco and “ Protolenus limestone” of Comley, Shropshire; Gerd Geyer, personal communication 2004).

Stratigraphic range and distribution.—Lower Cambrian, South China, Australia, Antarctica, and North−East Greenland, possibly Kazakhstan. Lower Middle Cambrian of southern Morocco and possibly England.