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Phycologia (2011) Volume 50 (2), 144–155 Published 3 March 2011

A re-description of Lithothamnion crispatum and the status of
Lithothamnion superpositum (Rhodophyta, Corallinales)

DANIELA BASSO1*, GRAZIELLA RODONDI2 AND GUIDO BRESSAN3

1Universita` degli Studi di Milano – Bicocca, Dip.to di Sc. Geologiche e Geotecnologie, Piazza della Scienza 4,
20126 Milano, Italy

2Universita` degli Studi di Milano, Dip.to di Biologia, Sezione di Botanica Sistematica, Via Celoria 26, 20133 Milano, Italy
3Universita` degli Studi di Trieste, Dip.to di Scienze della Vita (DSV) Via Giorgieri 1, 34127 Trieste, Italy

BASSO D., RODONDI G. AND BRESSAN G. 2011. A re-description of Lithothamnion crispatum and the status of
Lithothamnion superpositum (Rhodophyta, Corallinales). Phycologia 50: 144–155. DOI: 10.2216/10-20.1

After re-examination of the original Hauck’s collection, a buried, empty multiporate tetrasporangial conceptacle was
detected in the lectotype material of Lithothamnion crispatum. The morphology and anatomy of the type material were
compared to freshly collected representative plants from the Mediterranean. In L. crispatum, the five to seven rosette
cells surrounding each pore of the tetra/bisporangial conceptacle roof are larger than the normal epithallial cells and
undergo degeneration. As a consequence of the disintegration of the outermost cells in filaments surrounding the pore
canals, the tetra/bisporangial conceptacle roofs appear pitted with depressions, each one hosting a pore and the
surrounding rosette cells. A previous revision of the type material of Lithothamnion superpositum from South Africa
showed this same tetra/bisporangial conceptacle roof structure and development, and corresponding vegetative and
reproductive characters. These taxa are thus conspecific; therefore, L. superpositum is a younger heterotypic synonym of
L. crispatum, the latter having nomenclatural priority. While the type specimen lacked gametangial plants, these are
described for representative freshly collected material and found to be dioecious.

KEY WORDS: Coralline algae, Rhodoliths, Lithothamnion crispatum, Lithothamnion superpositum, Mediterranean,
Taxonomy, Hauck

INTRODUCTION (1998) also compared this material with the lectotype of
Lithothamnion philippii Foslie from the Foslie Herbarium in
Lithothamnion crispatum Hauck is a poorly known, Trondheim (TRH) and with the lectotype of Lithothamnion
uncommon Mediterranean species of nongeniculate coral- philippii Foslie f. crispata (Hauck) Foslie, also from TRH.
line algae (Bressan & Babbini 2003). The plant was They concluded that L. crispatum Hauck was conspecific
originally described from material collected in the northern with Lithothamnion philippii Foslie f. crispata (Hauck)
Adriatic Sea (Rovigno, presently spelt Rovinj) at 25 m Foslie, and that Lithothamnion philippii Foslie belonged to
depth (Hauck 1878). The species underwent substantial a different species.
nomenclatural changes. Originally described as Lithotham-
nion crispatum Hauck (1878: 289), it was later transferred to The aim of this paper is to provide a complete description
Lithophyllum crispatum (Hauck) Hauck (1885: 270). Then of L. crispatum, based on the discovery of empty tetra/
Foslie established the new combination Archaeolithotham- bisporangial conceptacles in the lectotype material as well
nion crispatum (Hauck) Foslie (1898: 3) but finally reduced as on additional material collected from the Mediterranean
it to the rank of forma, as Lithothamnion philippii Foslie f. Sea.
crispata (Hauck) Foslie (1904a: 13), on the basis of other
sterile material collected in Rovinj by Liechtenstern (Hauck MATERIAL AND METHODS
1878) and additional fertile specimens obtained by Anna
Vickers in 1900 (Foslie 1904a; see also Woelkerling et al. Plants were collected at the Egads Archipelago (Marettimo
2005: 332–333). Lemoine (1911) resurrected Lithothamnion Island, Italy), Elba Island (Tyrrhenian Sea, western
crispatum Hauck (1878) as a distinct and valid species and Mediterranean, Italy), Rovinj (type locality in the northern
her choice was followed until present. However, Hauck Adriatic Sea, Croatia), Moscenicka Draga (Rijeka Bay,
(1878) did not designate a type specimen and the lectotype Adriatic Sea, Croatia) and Aegean Sea and deposited in MI
material was selected among Hauck’s original material and TSB (abbreviations after Holmgren et al. 1990). Type
conserved in the Rijksherbarium, Leiden (L) by Woelker- material of L. crispatum Hauck deposited in L, and of L.
ling & Verheij (1995: 44). philippii Foslie and L. indicum Foslie, currently housed in
TRH, were also examined.
A modern revision of the lectotype of L. crispatum
Hauck in L was undertaken by Cabioch & Mendoza (1998), Specimens for scanning electron microscopy (SEM) were
who concluded that it was sterile. Cabioch & Mendoza first air-dried, then fractured and mounted on aluminium
stubs with Leit-C conductive carbon cement-306. The
* Corresponding author (daniela.basso@unimib.it). samples were gold-coated and examined in a SEM Cam-

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