Flabellopora, d'Orbigny, 1851

Martino, Emanuela Di & Taylor, Paul D., 2018, Early Pleistocene and Holocene bryozoans from Indonesia, Zootaxa 4419 (1), pp. 1-70 : 63

Flabellopora sp.

( Figs 193, 194 ; Table 41)

Figured material. RGM.1350601, early Pleistocene, Java.

Description. Colony rooted, lanceolate, bilaminar, small, about 2.1 mm long by 1.8 mm wide, the adapical angle (ca 68˚) similar to the antapical angle (ca 65˚). Zooidal boundaries not clearly defined, however both colony surfaces are characterized by irregularly polygonal depressions between mamillate ridges, which may correspond to autozooidal outline; calcification smooth. Orifices arranged radially from the colony axis, and placed subdistally within the depressions, subcircular, surrounded by a narrow, slightly raised peristomial rim; a small U-shaped sinus is visible in some of the apertures. One or two marginal areolar pores, variable in size (25–45 µm in diameter), included within each depression. Circular polymorphs, 60–75 µm in diameter, scattered among autozooids. Oval rootlet pores, about 70–85 µm long by 50–60 µm wide, visible on the adapical edge, surrounded by a thick, granular calcification.

Remarks. Only two small colonies of Flabellopora sp. were found in our samples. Flabellopora is an Indo- Pacific genus recorded from Japan to Australia, with numerous species (10 spp.) described from the Philippines by Canu & Bassler (1929) that await revision as highlighted by Bock & Cook (2004). Flabellopora sp. is similar in the general appearance to F. tuberosa Canu & Bassler (1929 , p. 501, pl. 74, figs 4–6). However, these authors mention in their description the presence of a distal, elliptical avicularium with pivotal bar and a proximal avicularium, both lacking in our specimens. Scattered, small, circular polymorphs were observed in our material which may be interpreted either as avicularia or kenozooids, although the revised diagnosis of the genus given by Bock & Cook (2004) mentions small and rounded avicularia with bars among the orifices but no kenozooids.

N, Number of colonies and number of zooids measured; SD, standard deviation.

Figures

FIGURES 193, 194. Flabellopora sp., RGM.1350601, early Pleistocene, Java. 193. General view of a colony. The following abbreviations were used to distinguish examples of: orifices (Or), polymorphs (Pm), and rootlet pores (Rp). 194. Close-up of the colony surface with autozooidal apertures and polymorphs. Scale bars: Fig. 193 = 400 µm; Fig. 194 = 200 µm.