Hello all sorry for the massive break in between posts I have been really busy with work and volunteering and time has rather evaded me ! I hope you have all had a good summer especially with the weather continuing to surpass expectations. I recently read about a fascinating new fossil discovery which makes up the content of this post. I hope you enjoy the blog.
First insect fossils
recorded in Late Kimmeridgian marine limestones.
Field studies taking place
between 2012 and 2013 led by French researchers and aided by two teams of
amateur scientists the Société des Naturalistes et Archéologues de l'Ain and
the Group 'Sympetrum Recherche et Protection des Libellules' in Orbagnoux,
France on the Late Kimmeridgian marine limestone’s have recorded a historical
first recent publications have revealed. The marine limestones are well known
for their abundance of fish and terrestrial fauna. There had however only been
one previous terrestrial based discovery before the findings of this latest
research came to light, when plant remains had been found to of been
transported in lagoons. As a result, this is the first occasion where insects and
evidence of insect activity have been recorded in the area.
The discovery of a 6mm specimen
of the species now known as Gallomesovelia
grioti of the basal mesoveliidae family
comprising of water treaders make it the oldest record to date of gerromorpha bugs . Modern water treaders
have a predatory nature, living in humid locations with either a terrestrial or
freshwater lifestyle. It has been theorised that Gallomesovelia grioti potentially could have lived in the near proximity
of sea margins or as some modern species of mesoveliidae can in brackish parts
of lagoons. Characteristics of gerromorpha species include large compound eyes
and a rounded head not conversed transversely.
Also discovered was evidence of
damage to zamite leaves as a result of insect feeding behaviour. Evidence of
this activity in the fossil record in the late Jurassic is rare in comparison
to records from the Triassic and Lower Cretaceous period and as such every
recording is particularly welcomed. Signs of insect activity on zamite leaves
illustrate there would have been a significant level of insect diversity and insect
fauna it would appear was not restricted to aquatic or subaquatic bugs. Fossil
evidence found in the limestone provides evidence of terrestrial insects
utilising emerged lands with Jurassic lagoons in close proximity. The majority
of the fieldworks findings however consisted of ammonites, bivalvia, shrimps,
isopods and fish. These recent studies it would suggest show evidence of close
terrestrial biota.
As a result of the excellent
preservation of the recovered fossils, it appears likely the Kimmeridgian
limestones are going to prove invaluable in increasing knowledge of the insect
diversity of the Upper Jurassic, due to the superior quality of fossil
preservation in comparison to those from the Bavarian lithographic limestone.
This period proved to be an important time for the transition of evolution in
terrestrial environments as the diversifying of flowering plants in the Lower
Cretaceous period approached.
Source
Nel A, Nel P, Krieg-Jacquier R, Pouillon J, Garrouste R.
(2014) Exceptionally preserved insect fossils in the Late Jurassic lagoon of
Orbagnoux (Rhône Valley, France) PeerJ 2:e510 http://dx.doi.org/10.7717/peerj.510
That is all for this time I plan to get back into the habit of posting on a weekly basis so keep an eye out for it !
Thanks for reading George.
