''Lectavis'' is a

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 enantiornithine

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s. 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 preserved ...

bones have been recovered from the Late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

(

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval ...

, c. 70.6 – 66 mya)

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 ...

at ''

estancia An estancia is a large, private plot of land used for farming or raising cattle or sheep. Estancias in the southern South American grasslands, the ''pampas'', have historically been estates used to raise livestock, such as cattle or sheep. In Pu ...

'' El Brete,

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. 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 branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''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 Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

''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 s ...

(lower leg) and tarsometatarsus (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

autapomorph 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 ...

ically 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 cond ...

, 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 ...

'' and '' Avisaurus'', but more likely closer to other

Euenantiornithes 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 ...

(Sanz ''et al.'' 1995). Its exact relationships, as with most enantiornithine birds, are unresolved however.

Paleoecology

Thus, it can be concluded 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 estu ...

– 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 paral ...

with

wader 245px, A flock of Dunlins and Red knots">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 mudflat ...

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

courser The coursers are a group 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 as waders is that ...

, 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
Euenantiornitheans Bird genera Maastrichtian life Cretaceous birds of South America Cretaceous Argentina Fossils of Argentina Lecho Formation Fossil taxa described in 1993 {{paleo-bird-stub