Juravenator
Name:
Juravenator
(Jura hunter).
Phonetic: Jooh-ah-ven-ah-tor.
Named By: G�hlich & Chiappe - 2006.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Coelurosauria, Compsognathidae.
Species: J. starki (type).
Diet: Carnivore/Insectivore.
Size: 70 centimetres long.
Known locations: Germany, Jura Mountains.
Time period: Kimmeridgian of the Jurassic.
Fossil representation: Single specimen of a
juvenile, and a skin impression.
Juravenator
was a small predatory dinosaur active in the late Jurassic of
Europe. It appears to have been a fleet footed hunter that
specialised in either invertebrates or small vertebrates like lizards.
The scleral rings of Juravenator show similarities
with nocturnal
birds strongly suggesting that Juravenator was most
active at night.
The
holotype specimen of Juravenator was assumed to
have a covering of
primitive protofeathers, something that gave rise to the nickname
Borsti (after bristle haired dogs). However when skin impressions
belonging to Juravenator were initially described
they were found to
have no clear indication of protofeathers just scales. This is
markedly different from other members of the Compsognathidae such as
Sinosauropteryx
which are known to have had them. Other longer known
members of the group such as Compsognathus
neither confirm or deny the
presence of feathers, but Compsognathus itself is
morphologically
similar to the ‘dino-bird’ Archaeopteryx
in its
skeletal make up.
This means that the Compsognathidae group may either end up being
re-shuffled into feathered and non-feathered, or it should be
accepted that small dinosaurs being feathered is not a hard and fast
rule that can be applied to all genera.
Of
course further fossil discoveries may yet reveal a completely different
realisation, and a follow up study in 2010 by Xu Xing reported
that when viewed under Ultraviolet light a light covering of
protofeathers are visible. It’s possible that as a juvenile its
covering of feathers was not fully developed. However it is also
possible that Juravenator had protofeathers upon
hatching which then
disappeared when it grew older. Alternatively the type specimen may
have been in a moult when it died resulting in the appearance of
reduced feathers for the living animal.
Further reading
- A new carnivorous dinosaur from the Late Jurassic Solnhofen
archipelago. - Nature 440:329-332. - U. B. G�hlich & L. M.
Chiappe - 2006.
- Juravenator starki (Reptilia, Theropoda) ein
neuer Raubdinosaurier
aus dem Oberjura der Suedlichen Frankenalb (Sueddeutschland):
Skelettanatomie und Weichteilbefunde. - Archaeopteryx 24: 1–26. - U. B.
Goehlich, H. Tischlinger & L. M. Chiappe - 2006.
- Anatomy of Juravenator starki (Theropoda:
Coelurosauria) from the
Late Jurassic of Germany. - Neues Jahrbuch f�r Geologie und
Pal�ontologie - Abhandlungen 258 (3): 257–296. - L. M. Chiappe
& U. B. G�hlich - 2010.
- Re-evaluating Moodie's Opisthotonic-Posture Hypothesis in fossil
vertebrates. Part I: Reptiles - The taphonomy of the bipedal dinosaurs
Compsognathus longipes and Juravenator
starki from the Solnhofen
Archipelago (Jurassic, Germany). - Palaeobiodiversity and
Palaeoenvironments 92 (1): 119–168. - A. G. Reisdorf & M.
Wuttke - 2012.
- Two of a feather: a comparison of the preserved integument in the
juvenile theropod dinosaurs Sciurumimus and Juravenator
from the
Kimmeridgian Torleite Formation of southern Germany. - Christian Foth,
Carolin Haug, Joachim T. Haug, Helmut Tischlinger & Oliver W.
M. Rauhut - 2020.
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