Albertonicus: a genus of small dinosaurs from the Upper Cretaceous

Albertonic (lat.: Albertonykus) is a genus of small theropod dinosaurs of the Upper Cretaceous period (early Maastrichtian), which lived in the territory of modern North America.

Assigned to the Alvarezsauridae family, a group of supposedly insectivorous dinosaurs, it is known only from fossils so far found only in the Canadian province of Alberta. The only described species (type species) Albertonykus borealis was approximately the size of a domestic chicken, and its length with the tail was about 75 cm. Thus, this species of Albertonica is the smallest of all dinosaur species so far discovered in North America.

The generic name “Albertonykus” is formed from the name Alberta and the Greek word “onyk”, meaning “claws”, and translates as “clawed lizard from Alberta”. The specific name “borealis” comes from the Greek word “borealis”, which means “northern”.

Alvarezsaurids are known from only a few fossil finds. The only Albertonic find so far has been made in southwestern Canada near the city of Red Deer in the sedimentary rocks of the Horseshoe Canyon Formation, known for its abundance of fossils.

It is mainly about the front and hind limbs of at least two individuals from the so-called “accumulation of albertosaur bones” (this is an accumulation of fossils in which the bones of more than 20 individuals of the typical type of albertosaurus-Albertosaurus sarcophag) in the provincial Park of Dry-Island- Buffalo-Jamp, Albert’s province; Other finds (bones of the fingers) were discovered nearby.

These fossils were already found during excavations conducted from 2000 to 2003 under the direction of Philip John Currie, and have since been kept in the Royal Tyrrell Museum of Palaeontology. In 2006 they were identified by Nicholas R. Longrich (Nicholas R. longrich).

Phylogenetic analysis of the fossil material indicates a close (“sister”) relationship of Albertonica with Asian mononikins. This conclusion is consistent with the hypothesis that Alvarezsaurs originated in South America and then spread through North America to Asia.

Like other alvaressaurids, the short but strong forelimbs of the Albertonica were adapted for digging. However, they were too small to build anything out of the ground, so it is highly likely that the dinosaur used them to tear insect nests. An analysis of the paleontological information regarding the “house-building” social insects on which Albertonics could feed indicates that neither ants nor termites could have been a source of food for them.

The fact is that ants were hardly represented in the ecological systems of the Cretaceous period, and termites, constructing termite mounds in the form of hills, had not yet developed by that time they appeared no earlier than the Eocene. Therefore, only arboreal termites can be considered as insects that these dinosaurs could eat.

Corresponding fossils of this termite species, found in silicified petrified wood from the Horseshoe Canyon Formation, support this hypothesis: tree fossils often show tunnel systems that are similar to structures built by representatives of the primitive modern termite family, Termopsidae.

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