Floridinella Canu and Bassler, 1917

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 : 1679-1680

Genus Floridinella Canu and Bassler, 1917

( Figure 12 )

Type species

Floridinella vicksburgica Canu and Bassler, 1917 , by original designation. Oligocene, Vicksburgian (= Rupelian), Escambia County, Alabama, USA .

Diagnosis

Colony encrusting ( Figure 12 (a)) or tubular erect ( Figure 12 (b)). Autozooids elongate subhexagonal; zooidal boundaries grooved. Cryptocyst extensive, granular. Gymnocyst lacking or very narrow. Opesia terminal, occupying one-third to half of frontal surface; constricted just beyond mid-length ( Figure 12 (b)), proximal edge straight to slightly concave. Ovicells hyperstomial; opesia enlarged in ovicellate autozooids; ooecia?cryptocyst-like. Avicularia equivocal (see below).

Remarks

Floridinella resembles Floridina but supposedly lacks avicularia and has opesiae with less concave proximal edges. Although this genus was explicitly stated by Canu and Bassler (1917) to lack avicularia, Cook and Bock (2001) re-examined syntype specimens of the type species and found that Canu and Bassler had retouched their figures to remove the small disto-lateral avicularia present on the surfaces of the ovicells. According to Cook and Bock, these avicularia have a triangular rostrum and a calcified pivotal bar.

Winston (2016) regarded Floridinella as a junior synonym of Ammatophora Norman, 1903 . However, the type species of the latter genus – Membranipora nodulosa Hincks, 1877a – has large tubercles between the zooids and semi-elliptical opesiae unlike the trifoliate opesiae of the type species of Floridinella . Canu and Bassler (1920, p. 229) described the ovicell of Floridinella as ‘endozooecial and separated from the zooecia by a fold’. Whether the ooecium is gymnocystal or cryptocyst-like is uncertain. In the oldest species assigned to this genus – F. jeffersoni Taylor and McKinney, 2006 from the Maastrichtian of Alabama – the ovicell is hyperstomial with a cryptocyst-like ooecium ( Figure 12 (d)). This species also shows a trace of very narrow gymnocyst around the margins of the zooids ( Figure 12 (c)).

Range

Cretaceous (Maastrichtian) to Recent.

Figures

Figure 12. (a,b) Floridinella vicksburgica Canu and Bassler;Oligocene,Vicksburgian (= Rupelian),west bank of Conecuh River, Escambia County, Alabama, USA; (a) NHMUK BZ 8213, part of an encrusting colony showing autozooid and?kenozooids (left), one of which is arrowed; (b) NHMUK BZ 8214, autozooids in a tubular erect colony.(c,d) Floridinella jeffersoni Taylor and McKinney; Cretaceous, Maastrichtian,Prairie Bluff Chalk, Jefferson, Marengo County, Alabama, USA; holotype, NHMUK BZ 5043(1a); (c) non-ovicellate autozooid; (d) ovicellate autozooids. Scale bars: a = 500 µm; b, d = 200 µm; c = 100 µm.