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Bertorsonidra n. gen. (Bryozoa, Cheilostomata) a new genus for Tremopora prenanti Gautier, 1955
The Egadi specimens were found detached from A
their substrata or attached to corallinacean and
peyssonneliacean algae, except for a single colony B
fragment encrusting a sponge. Material invari-
ably originated from (pre)coralligenous bottoms, FIG. 4. — Attaching structures: A, broken colony of Bertorsonidra
ranging from 17 to 19 m in depth. This environ- prenanti (Gautier, 1955) n. comb. showing pillar-like structures
ment is characterized by the abundance of algae, emanating from the zooid basal walls; B, margin of a Mollia patellaria
mostly encrusting corallinales, peyssonneliaceans, (Moll, 1803) colony adhering to the surface of a corallinacean alga
the chlorophyceans Halimeda tuna (J.Ellis & Sol.) through long pillar-like structures. Scale bars: 500 μm.
J.V.Lamour. and Flabellia petiolata (Turra) Nizam.,
the scleractinians Leptosammia prouvoti Lacaze- Detritic Biocoenosis (sensu Pérès & Picard 1964)
Duthiers, 1897 and Astroides calycularis (Pallas, developed at about 40 m depth. Bryozoans include
1766) and gorgonaceans, among which Eunicella dominant Cellaria spp. internodes, together with
cavolini (van Koch, 1887). Bryozoans are abundant Reteporella couchii (Hincks, 1878), Smittina cervi-
and diversified including ubiquitous and typical cornis (Pallas, 1766), Pentapora fascialis (Pallas, 1766),
coralligenous species such as Scrupocellaria delilii Entalophoroecia deflexa (Couch, 1844), Platonea
(Audouin, 1826), Beania spp., Pentapora ottomuel- stoechas Harmelin, 1976 and Buskea nitida (Heller,
leriana (Moll, 1803), Margaretta cereoides (Ellis & 1867). Some other species, such as lichenoporids,
Solander, 1786), Rhynchozoon neapolitanum Gau- Copidozoum planum (Hincks, 1880), C. tenuirostre
tier, 1962, and locally, Adeonella calveti Canù & (Hincks, 1880) and Micropora coriacea (Johnston,
Bassler, 1930, Myriapora truncata (Pallas, 1766) 1847) were found, also encrusting corallinaceans
and Reteporella grimaldi (Jullien, 1903). Colonies (Di Geronimo et al. 1994).
of B. prenanti n. comb. from Algeria, sampled from
between 30 and 40 m, encrusted nodular calcareous From the above reported data, it follows that
algae (Gautier 1955, 1962). B. prenanti n. comb. seems to have a restricted geo-
graphic range and that it is extremely rare both in
Noteworthy, the same kind of substratum was uti- the geological past and nowadays. Interestingly, the
lised by the three specimens of B. prenanti n. comb. species has maintained sensibly unaltered its ecologi-
found in fossil assemblages, which can be inter- cal requirements through time, being selective of
preted as living in a depth range deeper than 10- the Coralligenous Biocoenosis sensu Pérès & Picard
15 m and shallower than about 40 m. Particularly, (1964), although seemingly not excluded from other
the Pianometa colony was one of the extremely bioconcretions. Such a feature makes this species an
rare bryozoans from bioclastic cobblestones rich useful tool for palaeoecological inferences.
in centimetre- to decimetre-sized rhodoliths, and
encrusted a corallinacean alga. Rhodoliths, whose The stratigraphic range of B. prenanti n. comb.
nuclei consist of large fragments of the scleractinian includes at least the middle part of the Early Pleis-
Cladocora caespitosa (Linnaeus, 1767), were deposited tocene, as the Pianometa and the Belice layers were
in pyroclastite layers in very shallow waters (Pedley et presumably deposited during the Emilian (Pedley et
al. 2001; AR pers. obs.). Similarly, the colony from al. 2001) and the Sicilian (see Sprovieri & Cusenza
Contrada Inferno along the Mazzarrà stream from 1972; Di Geronimo et al. 1994), respectively.
NE Sicily, was found on a sub-spherical rhodolith
sampled in a polymictic conglomerate layer, includ-
ing pebbles and cobbles, sometimes coated by algae
and rarely colonised by bryozoans (AR pers. obs.).
Finally, the colony from the Belice section comes
from silty-sandy layers, relatively rich in bioclasts,
small rhodoliths and algal coatings on large mol-
lusc shells, interpreted as derived from a Coastal
ZOOSYSTEMA • 2010 • 32 (3) 465
