Tamarro

Tamarro (named after a mythological creature in local culture) is a genus of troodontid theropod from the Late Cretaceous Talarn Formation (Tremp Group) of Spain. The genus contains a single species, Tamarro insperatus, known from a partial metatarsal described in 2021.^[1]

Tamarro Temporal range: Late Cretaceous, 66.1–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Holotype metatarsal MCD-7073
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Family:	†Troodontidae
Subfamily:	†Jinfengopteryginae
Genus:	†Tamarro Sellés et al., 2021
Species:	†T. insperatus
Binomial name
†Tamarro insperatus Sellés et al., 2021

Discovery and naming

The holotype of Tamarro, MCD-7073, a metatarsal, was found in 2003 at the Sant Romà d'Abella site, belonging to the Talarn Formation of the Tremp Group. In 2021, Sellés et al. described it as a new genus and species, Tamarro insperatus; the generic name is that of a small creature in the folklore of Pallars, Spain, while the specific name means "unexpected", referring to the unexpected discovery of the fossil.^[1]

Classification

Sellés et al. placed Tamarro in the Jinfengopteryginae, making it the first member of the subfamily from Europe. They also suggested that its ancestors migrated from Asia to Europe sometime between the Cenomanian and the Maastrichtian.^[1]

Troodontidae	Geminiraptor Hesperornithoides Sinovenatorinae Jinfengopteryginae Jinfengopteryx Liaoningvenator Philovenator IGM 100/1128 IGM 100/140 Tamarro IGM 100/44 Xixiasaurus Sinusonasus Tochisaurus Daliansaurus Gobivenator Troodontinae

Paleobiology

Analysis of the holotype suggests it was a subadult; its large size suggests it grew quickly early in its life.^[1]

Paleoecology

Hypothetical reconstruction of Tamarro insperatus based on related genera

Tamarro lived on the Ibero-Armorican Island, and its discovery increases knowledge about the diversity of small theropods on the Cretaceous European archipelago. It would have lived at the same time as dwarf sauropods and lambeosaurine hadrosaurs.^[1] The holotype of Calvarius, a styracosternan ornithopod, has also been named from the Talarn Formation.^[2]