Floridina 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 : 1678-1679

Genus Floridina Jullien, 1882

( Figure 11 )

Type species

Mollia antiqua Smitt, 1873 , by original designation. Recent, Atlantic Ocean off Florida, USA .

Diagnosis

Colony encrusting. Autozooids subhexagonal ( Figure 11 (a)), rounded distally; zooidal boundaries raised with a median groove. Cryptocyst extensive, granular. Gymnocyst lacking. Opesia terminal, occupying one-third to half of frontal surface; trifoliate, with deep opesiular indentations and lateral constrictions, the proximal edge forming a tongue. Ovicells immersed, the distal edge of the opesiae of fertile zooids formed by the distal zooid ( Figure 11 (d)). Avicularia vicarious, symmetrical ( Figure 11 (a,b)), about half the width of an autozooid but of similar length; opesia round, with broad median indentation; condyles lacking; rostrum acutely triangular, floor pustulose.

Remarks

In addition to the extant type species, which was recently redescribed by Winston (2016), Jullien (1882) referred three Cretaceous species to his new genus: Semieschara bimarginata d’ Orbigny, 1851a (pl. 654, figs 10–12), S. ringens d’ Orbigny, 1852a (pl. 709, figs 5–8) and Vincularia gothica d’ Orbigny, 1851a (pl. 654, figs 13–16). Canu (1900) added a further five Cretaceous species to the genus, plus three Cenozoic species and two more Recent species. Some 52 species of Floridina are currently listed by Bock (2017), ranging from Coniacian to Recent ( Voigt 1981a, p. 457 specified Coniacian as the stage of first appearance). The defining character used by most taxonomists in assigning species to Floridina has been the trifoliate form of the opesia (e.g. Voigt 1923, 1987; Knowles 2008) ( Figure 11 (a,c)). However, in the Cretaceous species F. impressipora ( Marsson, 1887) , the proximolateral opesiular identations may be separated from the opesia to form opesiules ( Voigt 1979). The shape of the avicularium shows some variability, with either a pointed or rounded rostrum, and varies in size relative to the autozooids. While most species of Floridina are encrusters, some are erect and have either vincularian (e.g. F. gothica ( d’ Orbigny, 1851a)) or bifoliate (e.g. F. granulosa Canu and Bassler, 1920 ) colonies. Oral spine bases are present in an early Eocene species provisionally assigned to Floridina by Gordon and Taylor (2015), whereas rounded tubercles occur at the corners of some zooids in an interstitial species attributed by Winston and Håkansson (1986) to F. parvicella Canu and Bassler, 1923 .

Range

Cretaceous (Coniacian) to Recent. Note that Schager (1968) considered all of the Cretaceous and non-American species assigned to this genus to be distinct, differing in the morphology and details of the avicularia from the American type and other species.

Figures

Figure 11. (a,b) Floridina antiqua (Smitt); NHMUK 1964.7.2.56pt; Recent, Ghana; (a) bleached fragment showing autozooids and two avicularia; all of the autozooids in view are ovicellate apart from the one in the upper left; (b) unbleached fragment with two avicularia. (c,d) Floridina regularis Canu and Bassler; NHMUK D34391; Miocene, Duplin Formation, Cape Fear River, North Carolina, USA; (c) non-ovicellate autozooids; (d) ovicellate autozooids. Scale bars = 100 µm.