Mawsonia
Name: Mawsonia
(named after J. Mawson?).
Phonetic: Maw-so-ne-ah.
Named By: J. Mawson & A. S.
Woodward - 1907.
Classification: Chordata, Sarcopterygii,
Actinistia, Coelacanthiformes, Mawsoniidae.
Species: M. gigas (type), M.
brasiliensis, M. lavocati, M. libyca, M. soba, M.
tegamensis, M.
ubangiana.
Diet: Carnivore.
Size: Up to 4 meters long, though isolated
fossils suggest that rare individuals may have grown slightly larger
than this.
Known locations: Fossils are mostly known from
across South America and North Africa. Individual countries known to
include Algeria, Brazil and Morocco.
Time period: Early Cretaceous.
Fossil representation: Numerous specimens ranging
from partial remains to a few almost complete individuals. Fossils of
the skull bones seem to be most common.
Coelacanths
are one of the few creatures that typify animal life in the Mesozoic
that are still alive today. Modern coelacanths are represented by the
genus Latimeria
that live in the deep waters of the Indian Ocean, the
largest examples of which are known to easily attain lengths of two
meters. Back in the early Cretaceous however these fish would have
been small fry, with impressively large coelacanths of the Mawsonia
genus reaching lengths of up to four meters, double that of the
largest observed Latimeria. Because of their
large size, Mawsonia
are rarely preserved complete, and specimens which are preserved,
are usually of smaller individuals under three meters. Skull bones
are usually the most common specimens of Mawsonia
due to the greater
bone density increasing the likelihood of those parts surviving long
enough to fossilize.
Mawsonia
like other coelacanths were probably predatory fish that would cruise
over the sea floor snatching up fish and larger invertebrates that were
sheltering in crevices amongst rocks and coral. We do not know for
certain however if Mawsonia were nocturnal like the
Latimeria
coelacanths that we know today. Interestingly, Mawsonia
may have
been more inclined to stray into shallower waters than what Latimeria
are known to. This is because most of the fossil bearing formations
that Mawsonia are known from were estuarine and
mangrove habitats back
in the early Cretaceous.
When
fully grown to such a large size, Mawsonia may
have had few
predators, though larger sharks,
pliosaurs
and perhaps even
spinosaurid
dinosaurs, may have still been potential dangers for
Mawsonia.
Chinlea - Macropoma
Further reading
- On the Cretaceous formation of Bahia (Brazil), and on
vertebrate fossils collected therein. Quarterly Journal of the
Geological Society of London 63:128-139 - J. Mawson &
A.
S. Woodward - 1907.
- Un nouveau Coelacanthid� du Cr�tac� inf�rieur du Niger, remarques
sur la fusion des os dermiques [A new coelacanth from the Lower
Cretaceous of Niger, remarks on fusion of the dermal bones]. -
Colloques Internationaux du Centre National de la Recherche
Scientifique, Paris, 1973. Probl�mes actuels de Pal�ontologie
(�volution des Vert�br�s). Centre National de la Recherche
Scientifique 218:175-190. - S. Wenz - 1975.
- Coelacanths from the Lower Cretaceous of Brazil. American Museum
novitates ; no. 2866. - John G. Maisey - 1986.
- A new coelacanth from the Early Cretaceous of Brazil
(Sarcopterygii, Actinistia). - Paleontological Research 6:
343-350. - Yoshitaka Yabumoto -2002.
- New mawsoniid coelacanth (Sarcopterygii: Actinistia) remains
from the Cretaceous of the Kem Kem beds, Southern Morocco - In
Mesozoic Fishes 3 – Systematics, Paleoenvironments and
Biodiversity, G. Arratia & A. Tintori (eds.):
pp.
493-506, 7 figs. - Lionel Cavin & Peter L. Forey
-
2004.
- New materials of a Cretaceous coelacanth, Mawsonia
lavocati
Tabaste from Morocco. - Bulletin National Science Museum Tokyo C
01/2005; 31:39-49. - Yoshitaka Yabumoto & Teryua
Uyeno
- 2005.
- New occurrence of Mawsonia (Sarcopterygii:
Actinistia) from
the Early Cretaceous of the Sanfranciscana Basin, Minas Gerais,
southeastern Brazil. - Geological Society, London, Special
Publications 01/2008; 295(1):109-144. DOI:
10.1144/SP295.8. - Marise S. S. de Carvalho & John
G.
Maisley - 2008.
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