Reptolunulites d’ Orbigny, 1852

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 : 1696-1698

Genus Reptolunulites d’ Orbigny, 1852

( Figure 25 )

Type species

Reptolunulites angulosa d’ Orbigny, 1852 , by subsequent designation ( Bassler 1935, p. 185). Cretaceous. Senonian (Turonian fide Voigt 1981a), Sougé, Loir-et-Cher, France.

Diagnosis

Colony encrusting. Autozooids hexagonal; zooidal boundaries well raised. Cryptocyst extensive, granular. Gymnocyst lacking. Opesia terminal, occupying about half of frontal surface; bell shaped to longitudinally ovoidal, lacking opesiular indentations and constrictions. Ovicells unknown. Avicularia vicarious, symmetrical, narrower than an autozooid; opesia elongate elliptical; rostrum rounded arch shaped.

Remarks

The type species of Reptolunulites was revised by Gordon and Taylor (2005) who reviewed previous publications (e.g. Cook and Voigt 1986) discussing its apparent intermediate status between an encrusting onychocellid and a free-living lunulitid. Two North American Late Cretaceous species have been assigned recently to Reptolunulites : R. zipfi Taylor and McKinney, 2006 from the Campanian of Delaware, USA, and Reptolunulites sp. described by Taylor (2008) from the Maastrichtian of southern California, USA. Both species have opesiular indentations at the proximolateral corners of the opesia, contrasting with the type species. In R. zipfi , the ovicell has a cryptocyst-like roof ( Figure 12 (e)) and the avicularia are spatulate ( Figure 25 (f)). Neither ovicells nor avicularia are known from the Reptolunulites sp. of Taylor (2008).

Range Cretaceous (Turonian to Maastrichtian).

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.

Figure 25. (a–c) Reptolunulites angulosa d’Orbigny; lectotype, MNHN R61485; Late Cretaceous (? Turonian), Sougé, Loir-et-Cher, France; (a) encrusting colony; (b) autozooids and avicularia; (c) early astogeny with ancestrula arrowed. (d–f) Reptolunulites zipfi Taylor and McKinney; holotype, NHMUK BZ 5057; Cretaceous, Campanian, Mount Laurel Formation, Chesapeake and Delaware Canal, New Castle County, Delaware, USA; (d) autozooids, some ovicellate, and avicularia; (b) ovicellate autozooid; (c) avicularium. Scale bars: a = 1 mm; b, f = 200 µm; c, d = 500 µm; e = 100 µm.