''Dahalokely'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of carnivorous abelisauroid

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

(

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

) of

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...

Discovery

In 2007, during an expedition by

Andrew Farke Andrew is the English form of a given name common in many countries. In the 1990s, it was among the top ten most popular names given to boys in English-speaking countries. "Andrew" is frequently shortened to "Andy" or "Drew". The word is derived ...

to the north of Madagascar, Joseph Sertich discovered near

Antsiranana Antsiranana ( mg, Antsiran̈ana ), named Diego-Suárez prior to 1975, is a city in the far north of Madagascar. Antsiranana is the capital of Diana Region. It had an estimated population of 115,015 in 2013. History The bay and city originally ...

the remains of a theropod new to science. In 2010, these were completely excavated by Sertich and Liva Ratsimbaholison. The fossils were then transported to the

United States of America The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...

to be prepared, repaired and scanned in the

Stony Brook University Stony Brook University (SBU), officially the State University of New York at Stony Brook, is a public research university in Stony Brook, New York. Along with the University at Buffalo, it is one of the State University of New York system' ...

. After casts had been made and stored in the

Raymond M. Alf Museum of Paleontology The Raymond M. Alf Museum of Paleontology is a paleontology museum in Claremont, California, that is part of The Webb Schools. It is the only nationally accredited museum on a secondary school campus in the United States. The museum has two circ ...

with inventory number RAM 16010, the original fossils were returned to Madagascar and added to the collection of the

University of Antananarivo University of Antananarivo (french: Université d'Antananarivo) is the primary public university of Madagascar, located in the capital Antananarivo. History The university traces its founding to 16 December 1955 and the formation of the Instit ...

. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''Dahalokely tokana'' was named by Farke and Sertich in 2013. The generic name ''Dahalokely'' means "small thief" in Malagasy, deriving from its estimated length of smaller than those of known abelisaurids. The specific name ''tokana'' means "lonely" in the same language in reference to the isolation of the Madagascan

subcontinent A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continents. Ordered from largest in area to smallest, these seven ...

. During the Turonian, Madagascar and India were part of the same landmass that had separated from the rest of

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

. ''Dahalokely'' is the only dinosaur known from Madagascar when the island was separate from Gondwana but still connected with India, forming Indo-Madagascar. In the

ZooBank ZooBank is an open access website intended to be the official International Commission on Zoological Nomenclature (ICZN) registry of zoological nomenclature. Any nomenclatural acts (e.g. publications that create or change a taxonomic name) need t ...

the genus has the

Life Science Identifier Life Science Identifiers are a way to name and locate pieces of information on the web. Essentially, an LSID is a unique identifier for some data, and the LSID protocol specifies a standard way to locate the data (as well as a standard way of descr ...

8147803A-D4BE-4BA9-9701-D853E 37DE411 and the species the LSID AFAE32BB-123A-45D4-B931-4FF2A ABAF41C. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

, UA 9855, was uncovered in what is informally named the

Ambolafotsy Formation The Ambolafotsy Formation is a Turonian aged geological formation in the Diego Basin of Antsiranana Province in Madagascar. It is a mostly terrestrial unit deposited during a marine regression close to the shoreline. The dinosaur ''Dahalokely'' h ...

, a

-age deposit of the Diego Basin in northern Madagascar, about 93 million years old.''Dahalokely''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org It consists of a partial skeleton lacking the skull, of a subadult individual, preserving vertebrae and ribs. These include the fifth neck vertebra, the first, second, sixth, seventh, eighth and ninth dorsal vertebrae, the left dorsal rib, the upper parts of two right ribs, the lower ends of two ribs and some rib fragments. The identification of the position of these elements is tentative. They were not found in articulation but were assumed to represent the same individual as they were discovered not a metre apart.

Description

Initial size estimates of ''Dahalokely'', at , were based on the assumption it was built like an abelisaurid. Should it have had the more elongated build of the noasaurids, it would have been long. It was estimated as being in length in 2016. The describing authors established several unique derived traits,

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

. The cervical vertebra has a

lamina Lamina may refer to: Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics * Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwee ...

, bone sheet, between the front joint process, the

prezygapophysis The articular processes or zygapophyses (Greek ζυγον = "yoke" (because it links two vertebrae) + απο = "away" + φυσις = "process") of a vertebra are projections of the vertebra that serve the purpose of fitting with an adjacent vertebr ...

, and a rear process, the epipophysis, the edge of which lamina is markedly convex, the convex part being longer than the vertebral body and separated from both the prezygapophysis and the epipophysis by conspicuous notches. With the first and second dorsal vertebrae, the prezygapophysis and the lamina between it and the vertebral body are arranged on a vertical line, the joint facet of the prezygapophysis and the front vertebral body face being positioned in the same plane. With the second dorsal vertebra, the joint facets of the rear joint processes, the

postzygapophyses The articular processes or zygapophyses (Greek ζυγον = "yoke" (because it links two vertebrae) + απο = "away" + φυσις = "process") of a vertebra are projections of the vertebra that serve the purpose of fitting with an adjacent vertebr ...

, are strongly concave. From at least the sixth dorsal vertebra onwards, the ''fossa'' or hollowed out area, below the prezygapophysis is divided into two smaller depressions.

Classification

In 2013 ''Dahalokely'' was assigned to the

Abelisauroidea Abelisauroidea is typically regarded as a Cretaceous group, though the earliest abelisauridae remains are known from the Middle Jurassic of Argentina (classified as the species Eoabelisaurus mefi) and possibly Madagascar (fragmentary remains of ...

. The phylogenetic position of ''Dahalokely'' among abelisauroids is uncertain. Its vertebrae and ribs have features of both main groups of abelisauroids, the

Noasauridae Noasauridae is an extinct family of theropod dinosaurs belonging to the group Ceratosauria. They were closely related to the short-armed abelisaurids, although most noasaurids had much more traditional body types generally similar to other ther ...

and the

Abelisauridae Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found ...

. A phylogenetic analysis published along with its first description found ''Dahalokely'' to be a basal noasaurid, but this result was only weakly supported. The incompleteness of the remains and the lack of material that overlaps with known skeletal elements of other abelisauroid species means that the relationships of ''Dahalokely'' within the Abelisauroidea are hard to determine.

References

{{Taxonbar, from=Q11514710 Abelisaurids Late Cretaceous dinosaurs Dinosaurs of India and Madagascar Turonian life Cretaceous Madagascar Fossils of Madagascar Fossil taxa described in 2013