Ogiva Jullien, 1882

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 : 1690-1691

Genus Ogiva Jullien, 1882

( Figure 20 )

Type species

Eschara actaea d’ Orbigny, 1851 , by original designation. Cretaceous, Senonian [?Coniacian], Fécamp, Seine-Maritime, Normandy, France . Canu (1900, p. 393) inexplicably gave two type

species for Ogiva , one Recent ( Vincularia elegans d’ Orbigny, 1851 ) and the other fossil (Eschara santonensis d’ Orbigny, 1850), neither of which is valid as the type species of the genus.

Diagnosis

Colony erect bifoliate, narrowly palmate ( Figure 20 (a)). Autozooids subhexagonal, rounded distally; zooidal boundaries sharply raised. Cryptocyst extensive, depressed. Gymnocyst lacking. Opesia terminal, occupying about half of frontal surface; subcircular to longitudinally elliptical, lacking opesiular indentations and lateral constrictions. Ovicells unknown. Avicularia vicarious, symmetrical ( Figure 20 (b,c)), about the same size as an autozooid; opesia central, longitudinally elliptical; rostrum long, triangular, end rounded, floor smooth.

Remarks

The elliptical shape of the opesia in both the autozooids and avicularia was highlighted by Jullien (1882) as an important diagnostic character of Ogiva . The genus name is misleading as it is derived from an ogival arch, which is a pointed Gothic arch, unlike the shape of the opesia in this bryozoan. In addition to the type species, Jullien listed in his new genus 11 Cretaceous species described originally by d’ Orbigny (1851–1854) and two Tertiary species, one questionably. Canu (1900) added numerous additional species to Ogiva , which he treated as a subgenus of Onychocella . By 1929, however, he considered Ogiva to be ‘an inexact Cretaceous genus’ ( Canu and Bassler 1929, p. 48).

Among species more recently described or attributed to this genus are Ogiva incompta Gordon and Taylor, 1999 , from the Paleocene (Thanetian) to Eocene (Ypresian), Red Bluff Tuff, Chatham Islands, New Zealand, and O . promonturiorum Voigt, 1924 and O. ellinorvoigtae Martha et al., 2015 , both from the Santonian of Germany. As in the type species, ovicells have not been recognised with certainty in any of these three species.

Range

Cretaceous [?Coniacian] to Late Miocene (Tortonian). The youngest species of Ogiva appears to be O. elongata ( Canu and Bassler, 1935) from Muddy Creek in Victoria, Australia.

Figures

Figure 20. Ogiva actaea (d’Orbigny); lectotype, MNHN R61509; Cretaceous, Senonian (?Coniacian), Fécamp, Normandy, Seine Maritime, France; (a) palmate colony; (b) avicularium and autozooids; (c) two avicularia. Scale bars: a = 500 µm; b, c = 200 µm.