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Bertorsonidra n. gen. (Bryozoa, Cheilostomata) a new genus for Tremopora prenanti Gautier, 1955

AB

C DE

                            F
                                                               G

FIG. 3. — Bertorsonidra prenanti (Gautier, 1955) n. comb., fossil specimens from Sicily: A-D, early Pleistocene from the Pianometa section,
central-eastern Sicily (PMC. R.I.Ps. B 9b); E-G, late Pliocene or early Pleistocene from Contrada Inferno, East of Furnari, NE Sicily (PMC.
R.I. B 9c); A, sterile zooids, some with avicularia; B, detail of A; C, ovicellate zooids; D, well-preserved primary orifice with condyles and
two oral spines; E, a few zooids, the sculpture of the frontal surface locally masked by dissolution at contact with overgrowing algae;
F, a proximally broken zooid with intact orifice; G, close-up of an avicularium. Scale bars: A-C, E, F, 500 μm; D, G, 100 μm.

ate orifices, which are dimorphic in ovicellate and      a strikingly similar morphological appearance and
non-ovicellate zooids, both with a shallow sinus,       several characters are actually shared with species
and, noticeably, the absence of oral spines.            of the genus Robertsonidra Osburn, 1952, except
                                                        for the pseudoporous lepraliomorph frontal wall,
  The attribution of B. prenanti n. comb. to the genus  that is not the case for Robertsonidra. Consequently,
Ramphostomella, as suggested by Gautier (1962) and      as none of the already established genera seems to
dubitatively by d’Hondt & Ben Ismail (2008) after       share all the morphological features observed in
examination of the unique known specimen from           the examined material Bertorsonidra n. gen. is here
Algeria, is precluded. The genus Ramphostomella, in     proposed to accommodate the species described
fact, possesses a centrally imperforate, umbonulo-      by Gautier. Particularly, the presence of pores in
morph frontal shield and pronounced ridges between      the frontal wall has been considered enough for
marginal areolae, markedly different orifice and ovi-     erecting the new genus, somewhat paralleling the
cell (see Gordon & Grischenko 1994). In contrast,

ZOOSYSTEMA • 2010 • 32 (3)                                        463
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