''Lectavis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 c ...

avialan Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds, and their closest relatives. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative defi ...

. Their

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

bones have been recovered from the Late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

(

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

, c. 70.6 – 66 mya)

Lecho Formation The Lecho Formation is a geological Formation (geology), formation in the Salta Basin of the provinces Jujuy Province, Jujuy and Salta Province, Salta of northwestern Argentina. Its strata date back to the Maastrichtian, Early Maastrichtian, and i ...

at ''

estancia An estancia or estância is a large, private plot of land used for farming or raising cattle or sheep. Estancias are located in the southern South American grasslands of Chilean and Argentine Patagonia, while the ''pampas'' have historically bee ...

'' El Brete,

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. The genus contains a single species, ''Lectavis bretincola''.

Etymology

It's naming means "Lecho Formation bird living at El Brete". ''Lectavis'', after

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''lectus'' ("bed") =

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many countries in the Americas **Spanish cuisine **Spanish history **Spanish culture ...

''lecho'' + Latin ''avis'', "bird". ''bretincola'', after the type locality ''estancia'' El Brete + Latin ''incola'', "inhabitant".

Description

The presently only known fossil bones ( PVL-4021-1) are mostly of the left

tibiotarsus The tibiotarsus is the large bone between the femur and the tarsometatarsus in the leg of a bird. It is the fusion of the proximal part of the tarsus with the tibia. A similar structure also occurred in the Mesozoic Heterodontosauridae. These ...

(lower leg) and

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 bird bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) a ...

(upper foot) of a single individual. ''L. bretincola'' was a sizeable bird, with a tibiotarsus and a tarsometatarsus which if complete must have been nearly long (Chiappe 1993). This remains indicate an animal with a length of , hip height of , and weight of . It possesses a hypotarsus, which it evolved autapomorphically from modern birds, as it covers the upper end of the second, not the third, toe's bones. This structure serves to attach and arrest the

posterior cruciate ligament The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the Medial condyl ...

, which in turn prevents the lower and upper leg from shifting out of position during walking.

Classification

It was a rather advanced species of enantiornithine and possibly quite closely related to ''

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 an ...

'' and ''

Avisaurus ''Avisaurus'' (meaning "bird lizard") is a genus of enantiornithine avialan from the Late Cretaceous of North America. Discovery ''Avisaurus archibaldi'' was discovered in the Late Cretaceous Hell Creek Formation of North America (Maastrichtian, ...

'', but more likely closer to other Euenantiornithes (Sanz ''et al.'' 1995). Its exact relationships, as with most enantiornithine birds, are unresolved however.

Paleoecology

It appears that ''L. bretincola'' was a much more terrestrial species than its relative '' Yungavolucris brevipedalis'' which lived at the same time and place. Its habitat was a richly vegetated coastal area that was dotted by – possibly

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

– lakes or small rivers (Chiappe 1993), and it might thus be that the present species represents a case of

parallel evolution Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure.Zhang, J. and Kumar, S. 1997Detection of convergent and pa ...

with

wader 245px, A flock of Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflats in order to foraging, ...

s and similar semi-aquatic forms, or even a running bird similar to an oversized

courser The coursers are a subfamily (Cursoriinae) of birds which together with the pratincoles make up the family Glareolidae. They have long legs, short wings and long pointed bills which curve downwards. Their most unusual feature for birds classed ...

, and quite unlike anything living today.

References

Bibliography

* Chiappe, Luis M. (1993): Enantiornithine (Aves) Tarsometatarsi from the Cretaceous Lecho Formation of Northwestern Argentina. ''American Museum Novitates'' 3083: 1-27. [English with Spanish abstract
PDF fulltext
* Sanz, José L., Chiappe, Luis M. & Buscalioni, Angela D. (1995): The Osteology of ''Concornis lacustris'' (Aves: Enantiornithes) from the Lower Cretaceous of Spain and a Reexamination of its Phylogenetic Relationships. ''American Museum Novitates'' 3133: 1-23. [English with Spanish abstract
PDF fulltext
Enantiornithes Bird genera Maastrichtian life Cretaceous birds of South America Cretaceous Argentina Fossils of Argentina Lecho Formation Fossil taxa described in 1993 {{paleo-bird-stub