''Lectavis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 ...

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 lightweigh ...

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 th ...

(

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 from ...

, c. 70.6 – 66

mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * Burmese ...

)

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 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 ...

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 ''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 sm ...

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

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

'', 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 ''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 '' ...

'' 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 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