Setosinella perfluxa, Martino, Emanuela Di & Taylor, Paul D, 2012

Martino, Emanuela Di & Taylor, Paul D, 2012, Pyrisinellidae, a new family of anascan cheilostome bryozoans, Zootaxa 3534, pp. 1-20 : 13-14

Setosinella perfluxa n. sp.

( Figs 31−38 ; Table 5)

Material examined. Holotype: NHML BZ 5849, Langhian (Middle Miocene), Indominco Mine, Bontang, East Kalimantan, Indonesia; Paratype: BZ 5850, details as for holotype.

Etymology. From the Latin per, through, and fluxus, flow, in reference to the name of the Marie Curie Project ‘Throughflow’ funding this research.

Description. Colony encrusting, multiserial, unilaminar, usually irregular in outline shape. Growing edge stepped implying intrazooidal budding. Oval pore windows (mean 38 µm by 16 µm) exposed along distal, distolateral and proximolateral vertical walls at the colony growing edge. Ancestrula resembling a very small autozooid (mean L = 140 µm, mean W = 120 µm), with up to ten spine bases visible around the entire mural rim, possibly with additional spine bases hidden by surrounding autozooids ( Fig. 33 ); budding a single periancestrular zooid distally. Autozooids small, rounded hexagonal, longer than broad (mean L/W = 1.24), separated by deep furrows. Gymnocyst narrow, more developed proximally and laterally of the orifice, separated from the extensive cryptocyst by a thin, salient mural rim which together with distal rim of opesia forms a pear-shaped wall around cryptocyst and opesia. Cryptocyst shelf-like, deep, flat and finely granular, perforated by two small reniform opesiules. Opesia semicircular, limited distally by the mural rim and proximally by a transverse salient trabeculum attached to the mural rim. Nine oral spine bases in non-ovicellate zooids, six in ovicellate autozooids, forming an arch around but somewhat distant (mean D = 28 µm) from the distal edge of the opesia ( Fig. 38 ); spine diameters ranging from 10 to 20 µm independently of their position. Ovicell hyperstomial, globular, prominent, slightly broader than long, smooth, the ectooecium completely calcified, resting on proximal gymnocyst of distal zooid and indenting its mural rim ( Fig. 34 ). Avicularia lacking.

Remarks. Compared with the Paleocene type species of Setosinella, this new Miocene species has slightly more oral spines (9 vs 7–8) which are placed significantly more distantly from the distal rim of the opesia and larger autozooids. Furthermore, it lacks avicularia, which also differentiates S. perfluxa from S. orbiculata . Distribution. Langhian (Middle Miocene) of East Kalimantan, Indonesian Borneo.

N (colonies, zooids) Mean SD Range Zooid length 3, 40 374 39 330–451 Zooid width 3, 40 300 45 223–382 Orifice length 3, 40 57 8 45–69 Orifice width 3, 40 84 10 57–132 Ovicell length 3, 9 159 12 145–187 Ovicell width 3, 9 172 15 147–189 Cryptocyst length 3, 40 199 20 125–167 Cryptocyst width 3, 40 222 30 131–219

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

Figures

FIGURES 31 − 38. Setosinella perfluxa n. sp., Miocene, Langhian, Indominco Mine, Bontang, East Kalimantan, Indonesia. 31. view of colony NHML BZ 5849, holotype, scale bar = 500 µm; 32. same, several autozooids, scale bar = 200 µm; 33. same, close-up of ancestrula, scale bar = 100 µm; 34. same, close-up of an ovicellate autozooid, scale bar = 100 µm; 35. view of colony NHML BZ 5850, paratype, scale bar = 500 µm; 36. same, early astogeny, scale bar = 200 µm; 37. same, close-up of a zooid showing two small reniform opesiules, scale bar = 100 µm; 38. same, close-up of a zooid at the colony growing edge, showing oral spine bases and distal pore window, scale bar = 100 µm.