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Re: The Hills Have New Papers



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
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and     dinogami@gmail.com
http://cactus.dixie.edu/jharris/

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