Re: The Hills Have New Papers

[Fabio Dalla Vecchia <fabdalla@tin.it>]

As Jerry mentioned our paper on PALAIOS, I send you my rough translation of 
the press release that the Friulian Natural History Museum of Udine sent to 
the Italian mass media.


220 MILLION YEARS OLD "CROC" NESTS DISCOVERED IN THE JULIAN ALPS  OF 
NORTHEASTERN ITALY



During summer 2003 some researchers of the Padua University discovered a 
dozen of odd, circular depressions preserved on the surface of a limestone 
bed along the Dogna valley, in the Italian Julian Alps (Udine Province).

They are dated to the interval of the geological time known as Late Carnian 
(Triassic period), about 220 million years ago, have a diameter of about 
three to five feet (100-160 cm), are two to eight inches (5-20 cm) deep and 
surrounded by a rim of petrified mud.

Although no eggs remains were found inside the depressions, the comparison 
with similar structures occurring in North and South America suggests that 
they are nests of extinct reptiles.



More than ten years before, some trackways were found in the same place but 
on a limestone bed surface occurring only four feet (1.3 m) higher in the 
rock wall. They belong to reptiles about 6-7 feet (2 meters) long and 
walking on four limbs, probably etosaurs, animals vaguely similar to a croc.



According to the paleontologists and geologists of the Padua University 
(Paolo Mietto, Daniele Piubelli, Nereo Preto and Manuel Rigo), the CNR 
(Comitato Nazionale per la Ricerca Scientifica) of Padua (Guido Roghi), the 
Museo Tridentino di Scienze Naturali (Marco Avanzini) and the Museo Friulano 
di Storia Naturale (Fabio M. Dalla Vecchia), who studied the specimens and 
the geology of the site, the nest maker was probably the same kind of 
reptile as the trackmaker.

Supporting this hypothesis is - in addition to the space/time coincidence - 
a nests size well corresponding with the size of the trackmakers.



This is the first time that a nesting site of those extinct animals is 
discovered.



The most extraordinary aspect is that the way of nest building is much more 
sophisticated and complex than that observed in living crocodiles and 
alligators.



The reptiles of the Dogna valley produced a bowl-like depression, open and 
rimmed as that built by some living birds (ostriches and flamingos, for 
example). This behaviour, complex and related to the parental care, was 
previously considered a characteristic of dinosaurs (birds and some 
non-avian dinosaurs), observed in the North American Troodon, a theropod 
lived 70 million years ago, over 150 million years after the Italian nests. 
To lay eggs, the living crocs dig a simple hole in the sand that they cover 
after laying; gators build mounds of dirt and plant fragments containing the 
eggs inside.

Surprisingly, the reproductive behaviour of some crurotarsal Triassic 
reptiles was more advanced (sophisticated) than that of their living 
relatives.



The study of the Italian fossil nests was worth of the cover of the 
September issue of the international journal PALAIOS.



HOW THE TRIASSIC NESTS ARE?

They are wide, round depressions, about three to five feet across. They are 
surrounded by a raised mud rim up to 8 inches high, made by the animal 
pushing outward the sediment, probably by its feet. Because of this, the rim 
is not regular but made of distinct mud layers pushed in different times.

The central part of the depressions preserves traces of organic matter of 
vegetal origin. Probably they are the remains of plants or algae that 
females brought to the nest to warm the eggs with the heat developed by 
decaying.

The nests are close each other and roughly equidistant (around three-four 
feet) a fact indicative of social behaviour. Therefore it not the case of 
single, isolated nests but a nesting site.



WHO DID THE NESTS?

Crocs and birds are the only living members of a group of Mesozoic 
reptiles - the Archosaurs - that had an extraordinary evolutionary success 
during the Mesozoic era, between 250 and 65 million years ago. The two main 
Archosaur lineages are those that led to the living species. The 
Ornithodirans lineage saw the great diversification of the dinosaurs, whose 
only living members are the birds.

The lineage leading to the living crocs includes an array of animals that 
spread during the Triassic period, between 240 and 200 million years ago, 
and are all extinct. They are the phytosaurs, predators at first sight very 
similar to crocs; the etosaurs, vegetarians with an armoured body; and the 
rauisuchians, ferocious and swift terrestrial predators. With the 
crocodylomorphs all those animals form the Crurotarsi group. The first 
species of the evolutionary lineage leading to living crocs (that is, the 
first crocodylomorphs) were found in rocks about 200 million years old.

Etosaurs, the probable authors of the Dogna valley nests, moved on four legs 
as the living crocs, but unlike these they used to keep their feet nearly 
vertical below the body, thus their gait was less sprawling. They were 
pacific plant-eaters that lived together with the first dinosaurs.



The study of the trackways revealed that the reptiles of the Dogna valley 
were about 6-7 feet (two meters) long, with a low and broad body. They did 
not crawl the belly and the tail on the ground as other more primitive 
reptiles did and still do. They progressed in a rather efficient way keeping 
their feet oriented forward instead of pointing them laterally (as, for 
examples, crocs as well iguanas do). The hind feet were elongated, with five 
toes (crocs have only four) and impressed a footprint about 8 inches (20 
centimeters) long, decidedly larger than the subcircular print of the 
forefoot.



To lay eggs those animals gathered in a sheltered place, at the margins of a 
wide lagoon with shores covered by  tropical vegetation, not very far from 
the open sea.



The Dogna region is already famous among vertebrate paleontologists for 
yielding skeletal remains - slightly older than the nests and also unique - 
of other large, extinct reptiles. Among them are the  placodont 
Protenodontosaurus italicus (a sea reptile vaguely similar to a turtle) and 
Bobosaurus forojuliensis, a marine predator about 10 feet long and possible 
ancestor of the Jurassic plesiosaurs.



Original press release translated by F.M. Dalla Vecchia



For more information and materials please contact the Museo Friulano di 
Storia Naturale (Udine, Italy)

Via Marangoni 39, I-33100 Udine, Italy

0039-0432/584711

mfsn@comune.udine.it



Or

the Curator of the Museum

giuseppe.muscio@comune.udine.it



For more info on the PALAIOS issue:

http://palaios.geoscienceworld.org/



----- Original Message ----- 
From: "Jerry D. Harris" <jharris@dixie.edu>
To: "DINOSAUR Mailing List" <dinosaur@usc.edu>
Sent: Wednesday, September 05, 2007 10:46 PM
Subject: The Hills Have New Papers


> OK, no they don't...but they _do_ have fossils in 'em...!
>
> > .........................................

> Avanzini, M., Dalla Vecchia, F.M., Mietto, P., Piubelli, D., Preto, N., 
> Rigo, M., and Roghi, G. 2007. A vertebrate nesting site in northeastern 
> Italy reveals unesxpectedly complex beahvior for late Carnian reptiles. 
> Palaios 22(5):465-475. doi: 10.2110/palo.2005.p05-137r.
>
> ABSTRACT: We interpret 13 large subcircular or horseshoe-shaped 
> depressions discovered in Late Triassic peritidal carbonate rocks of the 
> Dogna Valley in Udine Province, northeastern Italy, to be reptile nests. 
> These trace fossils show truncation of strata, elevated ridges of massive 
> sediment, and sediment infill within the depression differing in shape and 
> sedimentary structures from the host sediment. The palynological 
> assemblage of a shaly interbed close to the nest layer indicates a 
> Tuvalian age (late Carnian). Archosaurian footprints, produced possibly by 
> aetosaurs, are on a surface 130 cm above the nest-bearing layer. The 
> trackmakers are considered the most probable nest makers.
>
> ...................................................
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Jerry D. Harris
> Director of Paleontology
> Dixie State College
> Science Building
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