TRILOBITE BIOGEOGRAPHY OF GONDWANA 65
Neseuretus during the Early Ordovician.
Asaphids are a common component of the
Neseuretus Association across the entire Gond-
wanan region; however, the relationships within
the family are currently poorly understood, and
thorough taxonomic revision is required before
they can be used to test the hypothesis of area
relationships generated with the Reedocaly-
meninae.
Early Ordovician trilobite taxa potentially
able to provide a test for this hypothesis include
the dikelokephalinid Hungioides, which ranges
from western Europe to South America (Fortey
& Peel 1983), and two different groups of
trinucleids which occur in slightly deeper shelf
conditions. The closely related hanchun-
golithine trinucleid genera Hanchungolithus and
Ningkianolithus, regarded by Li (1994) as occur-
ring only in South China, have in fact also been
recorded in Avalonia, France, the Middle East,
Indo-China and possibly Spain (Dean 1966; El-
Khayal & Romano 1985; Beckly 1989; Rabano
1990), although South American material
originally assigned to Hanchungolithus (Hughes
et al. 1975, as Ichangolithus} has recently been
transferred to the Trinucleinae (Baldis & Pothe
de Baldis 1995). A second trinucleid group
comprises the genera Lordshillia, Anebolithus,
Famatinolithus and Incaia, which appear to be
closely related to each other within the Trinu-
cleinae, and occur in Avalonia, South China,
New Zealand and South America (Hughes et al.
1975). Future cladistic research on some of these
groups can hopefully provide further infor-
mation on Early Ordovician area relationships
across Gondwana and peri-Gondwana.
This project was greatly helped by the encouragement
and assistance of D.J. Siveter, who engaged the author
with considerable discussion on the evolution of the
Calymenidae, and provided access to his substantial
reference collection. Discussion with T.G. Waters
generated further ideas on appropriate methods of
biogeographic analysis. P. Janvier and Tong-Dzuy
Thanh provided useful information on Vietnamia dou-
villei, and casts of most of Mansuy's type material of
this species were provided by P. Racheboeuf. The
Early Ordovician map used in Figure 1 was generated
by D. Lees, and M.D. Sutton provided welcome tech-
nical assistance. W.T. Dean, A.W. Owen and M.
Romano reviewed the manuscript and made several
useful suggestions for its improvement. Funding for
the project was provided by a Natural Environment
Research Council D.Phil studentship.
References
BALDIS, B. & POTHE DE BALDIS, E. D. 1995. Trilobites
Ordovicicos de la Formacion Las Aguaditas (San
Juan, Argentina) y consideraciones estratigrafi-
cas. Boletin de la Academia National de Ciencas,
Corboda, 60,409-435.
BANKS, M. R. 1988. The base of the Silurian System in
Tasmania. In: COCKS, L. R. M. & RICKARDS, R. B.
(eds) A global analysis of the Ordovician-Silurian
boundary. Bulletin of the British Museum
(Natural History), Geology, 43, 191-194.
BARRANDE, J. 1868. Silurische Fauna aus der Umge-
bung von Hof in Bayern. Neues Jahrbuchfur Min-
eralogie, 6/7, 641-696.
BECKLY, A. J. 1989. A new Arenig trilobite fauna from
the Bangor area. North Wales. Bulletin of the
British Museum (Natural History), Geology, 45,
1-20.
BERGERON, J. 1890. Sur une forme nouvelle de trilo-
bite de la famille des Calymenidae [genre Caly-
menella]. Bulletin de la Societe Geologique de
France, 18,365-371.
BORN, A. 1918. Die Calymene Tristani-Stufe (mittleres
Unter-silur) bei Almaden, ihre Fauna,
Gliederung und Verbreitung. Abhandlungen der
senckenbergischen naturforschenden Gesellschafi,
36, 309-358.
CHEN Xu & QIU JUNYU. 1986. Ordovician palaeo-
environmental reconstruction of Yichang area,
W. Hubei. Journal of Stratigraphy, 10, 1-15.
CHEN XU, RONG JIAYU, WANG XIAOFENG, WANG
ZHIHAO, ZHANG YUANDONG & ZHANG RENBIN.
- Correlation of the Ordovician rocks of
China. International Union of Geological
Sciences, Publication 31.
COCKS, L. R. M. 2001. Ordovician and Silurian global
geography. Journal of the Geological Society,
London, 158,197-210.
COCKS, L. R. M. & FORTEY, R. A. 1988. Lower Palaeo-
zoic facies and faunas around Gondwana. In:
AlJDLEY-CHA]'RLES, M. G. & HALLAM, A. (eds)
Gondwana and Tethys. Geological Society,
London, Special Publications, 37,183-200.
COCKS, L. R. M. & FORTEY, R. A. 1990. Biogeography
of Ordovician and Silurian faunas. In: Mc-
KERROW, W. S. & SCOTESE, C. R. (eds) Palaeozoic
Palaeogeography and Biogeography. Geological
Society, London, Memoirs, 12, 97-104.
CORBETT, K. D. & BANKS, M. R. 1974. Ordovician
stratigraphy of the Florentine Synelinorium,
south-west Tasmania. Papers and Proceedings of
the Royal Society of Tasmania, 55, 1-55.
COURTESSOLE, R., PlLLET, J. & VIZCAINO, D. 1981.
Nouvelles donnees sur la biostratigraphie de
l'Ordovicien inferieur de la Montagne Noire.
Revision des Taihungshaniidae, de Megistaspis
(Ekeraspis) et d'Asaphopsoides (Trilobites).
Memoire de la Societe des Etudes Scientifiques de
l'Aude. Carcassonne, France.
DEAN, W. T. 1966. The Lower Ordovician stratigra-
phy and trilobites of the Landeyran valley and
the neighbouring district of the Montagne Noire,
south-western France. Bulletin of the British
Museum (Natural History), Geology, 12,
247-353.
DEAN, W. T. 1 967a. The correlation and trilobite fauna
of the Bedinan Formation (Ordovician) in south-
eastern Turkey. Bulletin of the British Museum
(Natural History), Geology, 15, 83-123.