''Martinavis'' is a genus of

enantiornithine The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cla ...

birds which existed in what is now southern France,

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

and

Salta Province Salta () is a province of Argentina, located in the northwest of the country. Neighboring provinces are from the east clockwise Formosa, Chaco, Santiago del Estero, Tucumán and Catamarca. It also surrounds Jujuy. To the north it borders Boliv ...

, Argentina during the late Cretaceous period. It was named by Cyril A. Walker, Eric Buffetaut and Gareth J. Dyke in

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, and the type species is ''Martinavis cruzyensis''.

Description

''M. cruzyensis'' is known from the holotype ACAP-M 1957, a complete uncrushed right

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

, recovered from the Massecaps locality,

Cruzy Cruzy (; Languedocien: ''Crusi'') is a commune in the Hérault department in southern France. The mezzo-soprano Simone Couderc was born in Cruzy on 3 June 1911. Population See also *Communes of the Hérault department The following is ...

, which is in a Campanian/ Maastrichtian-stage deposits in the

Grès à Reptiles Formation Grès was a French haute couture fashion house founded by Madame Grès in 1942. Parfums Grès is the associated perfume house, which still exists, and is now based in Switzerland. History Germaine Émilie Krebs (1903–1993), known as Alix Bar ...

of France. This species reached in length, in hip height and in weight. A second species, ''M. vincei'' is known from the holotype PVL 4054, a complete left humerus and from the associated paratype PVL 4059, a distal end of left humerus, recovered from the

El Brete EL, El or el may refer to: Religion * El (deity), a Semitic word for "God" People * EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer * El DeBarge, music artist * El Franco Lee (1949–2016), American po ...

locality ( Maastrichtian age),

Lecho Formation The Lecho Formation is a geological formation in the Salta Basin of the provinces Jujuy and Salta of northwestern Argentina. Its strata date back to the Early Maastrichtian, and is a unit of the Salta Group. The fine-grained bioturbated sandston ...

of Argentina. A possible third species is represented by the unnamed specimen KU-NM-37 from United States. In

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, three additional species were named from the same location as ''M. vincei'': * ''M. minor'' is known from the holotype PVL 4046, a distally imperfect right humerus; * ''M. saltariensis'' is known from the holotype PVL 4025, an incomplete left humerus, lacking the median ridge; * ''M. whetstonei'' is known from the holotype PVL 4028, a distally imperfect left humerus. ''M. vincei'' is the largest of the El Brete taxa, approaching its huge (by enantiornithine standards),

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

and coeval ''

Enantiornis ''Enantiornis'' is a genus of Enantiornithes. The type and only currently accepted species ''E. leali'' is from the Late Cretaceous Lecho Formation at El Brete, Argentina. It was described from specimen PVL-4035, a coracoid, proximal scapula ...

'' in size. PVL 4054 and PVL 4059 indicate the animals with a length of , hip height of , and weight of . ''M. saltariensis'' is the second largest species, with a length of , hip height of , and weight of . ''M. minor'' is notably smaller than the former two, while ''M. whetstonei'' was a diminutive version of ''M. vincei'', being at most half its size. In addition to size, the species differ slightly in proportions and qualitative features, making it unlikely the represent sexual or age variation.

Taxonomy

As few elements are known from El Brete ''Martinavis'', it might be the same species as one of the other enantiornithines of that locality which were described earlier based on leg bones. While the

tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) and meta ...

of ''

Yungavolucris ''Yungavolucris'' is a genus of enantiornithean birds. It contains the single species ''Yungavolucris brevipedalis'', which lived in the Late Cretaceous (Maastrichtian, c.70.6 – 66 mya). The fossil bones were found in the Lecho Formation at ' ...

'' seems too wide (and short) to match ''Martinavis'', and ''

Lectavis ''Lectavis'' is a genus of enantiornithine birds. Their fossil bones have been recovered from the Late Cretaceous (Maastrichtian, c. 70.6 – 66 mya) Lecho Formation at ''estancia'' El Brete, Argentina. The genus contains a single species, '' ...

'' was slightly larger (and its tibiotarsus differs from one tentatively assigned to ''Martinavis''), the ''

Soroavisaurus ''Soroavisaurus'' is a genus of enantiornithean birds related to '' Avisaurus''. It lived during the Late Cretaceous of Argentina. The only known species, ''S. australis'', is known from fossils collected from the Lecho Formation (Maastrichtian ...

'' tarsometatarsus is about the size expected for ''M. vincei'' and perhaps ''M. saltariensis''. These differ slightly in size but also in proportions, meaning ''M. saltariensis'', while generally smaller, might nonetheless have had thicker legs, and thus match ''Soroavisaurus''. As ''Yungavolucris'' is assumed to be a foot-propelled swimmer however the synonymity of at least some ''Martinavis'' specimens with it could explain the genus' prevalence in marine biomes.M. K. Brett-Surman, Thomas R. Holtz, James Orville Farlow, The Complete Dinosaur, Indiana University Press, 2012

References

Euenantiornitheans Late Cretaceous birds of North America Cretaceous birds of Europe Late Cretaceous animals of Europe Cretaceous France Fossils of France Cretaceous birds of South America Late Cretaceous animals of South America Cretaceous Argentina Fossils of Argentina Lecho Formation Maastrichtian life Fossil taxa described in 2007 Fossil taxa described in 2009 {{paleo-bird-stub