Pelecanimimus

*Pelecanimimus polydon*

***Pelecanimimus*** (meaning "pelican mimic") is a genus of basal ("primitive") ornithomimosaurian theropod dinosaur from the Early Cretaceous of Spain. It is notable for possessing more teeth than any other member of the Ornithomimosauria (or any other theropod), most of which were toothless.

## Discovery and naming

In July 1993 Armando Díaz Romeral discovered a theropod skeleton at the *Las Hoyas Unit 3* site. In 1994 this was named and described by Bernardino Pérez Pérez-Moreno, José Luis Sanz, Angela Buscalioni, José Moratalla, Francisco Ortega and Diego Rasskin-Gutman as a new species: *Pelecanimimus polyodon*. The generic name is derived from Latin *pelecanus*, "pelican", and *mimus*, "mimic", in reference to the long snout and throat pouch. The specific name is a reference to the large number of teeth possessed by this theropod and is derived from Greek πολύς (*polys*), "many" and ὀδούς (*odous*) "tooth".

The holotype specimen, **LH7777**, part of the Las Hoyas Collection presently housed at the Museo de Cuenca, Cuenca, Spain, of *Pelecanimimus* was recovered at the La Hoyas locality in Cuenca Province, Spain, from lagerstätte beds within the Calizas de La Huérguina Formation dating to the Lower Barremian.
The only known specimen consists of the articulated front half of a skeleton and includes the skull, lower jaws, all the neck vertebrae and most of the back vertebrae, ribs, sternum, the pectoral girdle, a complete right forelimb and most of the left forelimb. Remains of the soft parts are visible at the back of the skull, around the neck and around the front limbs.

## Description

*Pelecanimimus* was a small ornithomimosaur, at about 2–2.5 m (6.6–8.2 ft). Its skull was unusually long and narrow, with a maximum length of about 4.5 times its maximum height. It was highly unusual among ornithomimosaurs in its large number of teeth: it had about 220 very small teeth in total, with seven premaxillary teeth, about 30 maxillary, and 75 in the dentary. The teeth were heterodont, showing two different basic forms. The teeth in the front of the upper jaw were broad and D-shaped in cross-section, while those further back were blade-like, and on the whole the teeth in the upper jaw were larger than those in the lower. All of its teeth were unserrated, and had a constricted "waist" between the crown and the root. Interdental plates were lacking.

Only one other ornithomimosaur is known to possess teeth, *Harpymimus*, which had far fewer (eleven total, and only in the lower jaw). The presence of such a large number of teeth in *Pelecanimimus*, coupled with a lack of interdental space, was interpreted by Pérez-Moreno *et al.* as an adaptation for cutting and ripping, a "functional counterpart of the cutting edge of a beak," as well as an exaptation leading to the toothless cutting edge found in later ornithomimosaurs.

The arms and hands of *Pelecanimimus* were more typical of ornithomimosaurs, with the ulna and radius bones in the lower arm tightly adhered to each other. The hand was hook-like and had fingers of equal length equipped with rather straight claws.

Soft-tissue remains preserved by the exceptional preservational environment of the La Hoyas lagerstätte revealed the presence of a small skin or keratin crest on the back of the head, and a gular pouch similar to the much larger pouches found in modern pelicans, from which *Pelecanimimus* took its name. *Pelecanimimus* might have been much like a modern day crane, wading out in lakes or ponds using its claws and teeth to capture fish and then storing them in its skin flap. Some parts of the impressions revealed wrinkled skin, interpreted as lacking scales or feathers. Filament-like structures were also preserved; first interpreted as an integument, some of these were later seen as representing preserved muscle fibers. *Pelecanimimus* was also the first ornithomimosaur discovered with a preserved hyoid apparatus (specialized tongue bones in the neck).

## Phylogeny and evolution

*Pelecanimimus* was by the describers assigned to the Ornithomimosauria, in the basalmost position. A later cladistic analysis by Makovicky *et al.* (2005) confirmed that *Pelecanimimus* is the most basal member of the Ornithomimosauria, less derived even than *Harpymimus*. A study by Kobayashi and Lü in 2003 indicated that these two species formed a basal arrangement of steps leading towards the more advanced ornithomimids (see cladogram below). The discovery of *Pelecanimimus* has played an important and surprising role in understanding the evolution of the Ornithomimosauria. To quote Pérez-Moreno *et al.*, "The phylogenetic hypothesis...supports an unexpected approach, involving exaptation, which might explain the evolutionary process towards the toothless condition in Ornithomimosauria. Until now, a progressive reduction in the number of teeth has been considered as the most likely explanation: the primitive tetanurine theropods have up to 80 teeth with tall blade-like crowns, and the primitive ornithomimosaurs have only a few small teeth. The phylogenetic hypothesis suggests an alternative evolutionary process based on a functional analysis of increasing numbers of teeth. A high number of teeth with enough interdental space and properly placed denticles (as in troodontids) would be an adaptation for cutting and ripping. On the other hand, an excessive number of teeth with no interdental space (as in *Pelecanimimus*) would be a functional counterpart of the cutting edge of a beak. Thus, increasing the number of teeth would be an adaptation for cutting and ripping, as long as the space between adjacent teeth was preserved...while it would have the effect of working as a beak if spaces were filled with more teeth. The adaption to a cut-and-rip function therefore becomes an exaptation with a slicing effect, eventually leading to the cutting edge seen in most ornithomimosaurs."

Cladogram after Kobayashi and Lü, 2003:

## Paleobiology

The Las Hoyas lagerstätte has produced numerous other exquisitely preserved species, including the enantiornithine birds *Iberomesornis*, *Concornis*, and *Eoalulavis*, along with non-avian theropod teeth and a few fragmentary sauropod bones. Coarse sediments of the La Hoyas lagerstätte have produced bones of the ornithopod dinosaur *Iguanodon*. The lagerstätte beds have also yielded remains of lizards and salamanders.

## JPInstitute.com Description

This little dinosaur had the most teeth of any known meat-eater - 220 teeth! It is from the same dinosaur family that includes the Jurassic Park star Gallimimus. The strange thing is that almost no members of that family had any teeth at all, they had sharp beaks! This little hunter lived in Cretaceous Europe and may have had one other feature that was somewhat unique feathers.

Pelicanimimus is considered a basal member of the ornithomimosaur family. Its large number of teeth did not have serrations and were very closely packed. It is thought that this feature may have been an evolutionary step in the development of the sharp cutting edge of a beak. This contradicts a theory that the formation of a beak came about through a reduction of teeth as opposed to an increase. Although considered a primitive form of ornithomimid, it had arms similar to later genera.

## Dinosaur Field Guide Description

Pelecanimimus (pelican mimic") is the earliest known ornithomimosaur, or "bird mimic" often called an ostrich dinosaur. It lived during the early part of the Cretaceous Period, whereas most ostrich dinosaurs lived millions of years later, during the Late Cretaceous Period. Like other ornithomimosaurs, Pelecanimimus has a small, pointed head at the end of a long neck. Its arms end in typical ostrich dinosaur hands- three fingers of the same length, all curving in the same direction. But unlike the Late Cretaceous ostrich dinosaurs, which have toothless beaks, Pelecanimimus has jaws filled with over 220 tiny teeth, It is also the smallest known ostrich dinosaur, being only 6.6 feet (2 m) long. Pelecanimimus is known only from a single skeleton from Spain. On that skeleton, an impression of skin was found around some of the bones. The impression indicated that there was a pouch underneath the lower jaw. like that of a pelican. However, when scientists examined these impressions more closely, they realized that these were not the outside surface of the skin but the inside tissue! This was one of the first times that a dinosaur's muscle tissue had been preserved. Unfortunately, because the fossiliza-ton process turned this tissue into rock.

### Fun Facts

Pelecanimimus was preserved in mud at the bottom of an ancient lagoon. The same rock contains the remains of many plants, insects, fish, lizards, crocodiles, and at least three bird species.

### Trivia

Pelecanimimus has more teeth than any other dinosaur known.

## Appearance in other media

### *Jurassic Park*

* *Pelecanimus* is a dinosaur the appears in *Jurassic Park III: Park Builder*.
* *Pelecanimimus* is a dinosaur who appears in *Jurassic World: The Game*. It is classified as a herbivore in-game, although in reality it would have likely eaten fish. The game model also lacks a throat pouch in any evolution. In its' final evolution, it is accurately portrayed with a coat of feathers.

## Links

http://web.archive.org/web/20040214162437fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_pelecanimimus.html
https://web.archive.org/web/20080705163939/http://kids.yahoo.com/dinosaurs/402--Pelecanimimus

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Perez-Moreno, B. P., Sanz, J. L., Buscalioni, A. D., Moratalla, J. J., Ortega, F., and Raskin-Gutman, D. (1994). "A unique multitoothed ornithomimosaur from the Lower Cretaceous of Spain." *Nature*, **370**: 363-367.
2. ↑ Kobayashi, Y., and Barsbold, R. (2005). "Anatomy of *Harpymimus okladnikovi* Barsbold and Perle 1984 (Dinosauria; Theropoda) of Mongolia." in *The Carnivorous Dinosaurs* ed. Carpenter, K. 2005. Indiana University Press:97-126.
3. ↑ D. E. G. Briggs, P. R. Wilby, B. Pérez Pérez-Moreno, J. L. Sanz, M. Fregenal-Martinez, (1997). "The mineralization of dinosaur soft tissue in the Lower Cretaceous of Las Hoyas, Spain." *Journal of the Geological Society London*, **154**: 587-588.
4. ↑ Makovicky, P., Kobayashi, Y. and Currie, P. J. (2004). "Ornithomimosauria." pp. 137-150 in D. B. Weishampel, P. Dodson, et H. Osmólska (eds.), *The Dinosauria*. 2nd ed. University of California Press, Berkeley.
5. ↑ 5.0 5.1 Kobayashi, Y., and Lü, J.-C. (2003). "A new ornithomimid dinosaur with gregarious habits from the Late Cretaceous of China." *Acta Palaeontologica Polonica* 48:235-259.