Ehrhardina Martha and Taylor, 2016

Taylor, Paul D., Martha, Silviu O. & Gordon, Dennis P., 2018, Synopsis of ‘ onychocellid’ cheilostome bryozoan genera, Journal of Natural History (J. Nat. Hist.) 52 (25 - 26), pp. 1657-1721 : 1673-1674

Genus Ehrhardina Martha and Taylor, 2016

( Figure 8 )

Type species

Ehrhardina voigti Martha and Taylor, 2016 , by original designation. Cretaceous, early Cenomanian, Devon, England, United Kingdom .

Diagnosis

Colony encrusting, multilamellar; pore chambers present. Autozooids subhexagonal; zooidal boundaries raised with a medial groove ( Figure 8 (a,b)). Cryptocyst extensive, granular. Gymnocyst lacking. Opesia terminal, occupying about one-third to half of the frontal surface; semicircular with moderate to deep opesiular indentations. Ovicells hyperstomial, ooecium gymnocystal with a median suture ( Figure 8 (c)). Avicularia interzooidal, symmetrical, small ( Figure 8 (b)), less than half the size of an autozooid; opesia longitudinally elliptical; rostrum spatulate, floor smooth.

Remarks

Martha and Taylor (2016) introduced this genus for two new early Cenomanian species, the type species, E. voigti , from Devon in the United Kingdom, and E. pikeae Martha and Taylor, 2016 , from North-Rhine Westphalia in Germany. Key features of the type species are the gymnocystal ooecium which contrasts with the cryptocyst-like ooecia seen in most other onychocellid genera that have non-immersed ovicells. Having an exteriorwalled ooecium can be interpreted as a primitive condition, possibly inherited from an ancestral form resembling Wilbertopora Cheetham, 1954 (see Ostrovsky 2013). Intact ovicells have not been seen in E. pikeae but autozooidal morphology is very similar to the type species. The avicularia in E. pikeae , however, are larger and have folds of gymnocyst over their opesiae.

Range

Cretaceous (early Cenomanian).

Figures

Figure 8. Ehrhardina voigti Martha and Taylor. (a) NHMUK D37713; part of colony showing autozooids and avicularia; Cenomanian, Whitecliff, Seaton, Devon, United Kingdom. (b,c) holotype, NHMUK B1833; Cenomanian Limestone, Sidmouth, Devon; (b) autozooids and an interzooidal avicularium (arrowed); (c) ovicell with median suture in the calcified ectooecium. Scale bars: a = 500 µm; b = 200 µm; c = 100 µm.