Lectavis
Encyclopedia
Lectavis is a genus
of enantiornithine
bird
. Its fossil
bones were recovered from the Late Cretaceous
(Maastrichtian
, c.70.6-65.5 mya) Lecho Formation
at estancia
El Brete, Argentina
. The genus contains a single species, Lectavis bretincola.
The only known (this far) fossil bones (PVL
-4021-1) are most of the left tibiotarsus
(lower leg) and tarsometatarsus
(upper foot) of a single individual. L. bretincola was a sizeable bird, with a 16-cm tibiotarsus and a tarsometatarsus which if complete must have been nearly 10 cm long (Chiappe 1993); this would make it roughly similar to a large curlew
in size and at least in leg shape. It is most interesting in possessing 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.
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 - lakes and/or small rivers (Chiappe 1993), and it might thus be that the present species represents a case parallel evolution
with waders and similar semi-aquatic forms, or even a running bird similar to an oversized courser
, and quite unlike anything living today.
It was a rather advanced species of enantiornithine and possibly quite closely related to Enantiornis
and Avisaurus
, but more likely closer to other Euenantiornithes
(Sanz et al. 1995). Its exact relationships, as with most enantiornithine birds, are unresolved however.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of enantiornithine
Enantiornithes
Enantiornithes is an extinct group of primitive birds. They were the most abundant and diverse avialans of the Mesozoic. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 50 species of Enantiornithines have been named, but some...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
. Its fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
bones were recovered from the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
(Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
, c.70.6-65.5 mya) Lecho Formation
Lecho Formation
The Lecho Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation....
at estancia
Estancias
Estancia or Estância is a Spanish and Brazilian Portuguese term describing a large rural estate with similarities to the English term ranch. The term is used in Argentina, Uruguay and southern Chile...
El Brete, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. The genus contains a single species, Lectavis bretincola.
The only known (this far) fossil bones (PVL
Universidad Nacional de Tucumán
The National University of Tucumán is a national university in the Tucumán Province, in the northwest region of Argentina.-General information:...
-4021-1) are most of the left tibiotarsus
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...
(lower leg) and tarsometatarsus
Tarsometatarsus
The tarsometatarsus is a bone that is found in the lower leg of certain tetrapods, namely birds.It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsal and metatarsal bones...
(upper foot) of a single individual. L. bretincola was a sizeable bird, with a 16-cm tibiotarsus and a tarsometatarsus which if complete must have been nearly 10 cm long (Chiappe 1993); this would make it roughly similar to a large curlew
Curlew
The curlews , genus Numenius, are a group of eight species of birds, characterised by long, slender, downcurved bills and mottled brown plumage. They are one of the most ancient lineages of scolopacid waders, together with the godwits which look similar but have straight bills...
in size and at least in leg shape. It is most interesting in possessing 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
Posterior cruciate ligament
The posterior cruciate ligament is one of the four major ligaments of the knee. It connects the posterior intercondylar area of the tibia to the medial condyle of the femur...
, which in turn prevents the lower and upper leg from shifting out of position during walking.
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 - lakes and/or small rivers (Chiappe 1993), and it might thus be that the present species represents a case parallel evolution
Parallel evolution
Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades.-Parallel vs...
with waders and similar semi-aquatic forms, or even a running bird similar to an oversized courser
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...
, and quite unlike anything living today.
It was a rather advanced species of enantiornithine and possibly quite closely related to Enantiornis
Enantiornis
Enantiornis is a genus of predatory enantiornithine bird. The type and only currently accepted species E. leali is from Late Cretaceous rocks at El Brete, Argentina....
and Avisaurus
Avisaurus
Avisaurus is a genus of enantiornithine bird from the Late Cretaceous of North America.Two species are known; the type species A. archibaldi and A. gloriae...
, but more likely closer to other Euenantiornithes
Euenantiornithes
Euenantiornithes is a superorder of Cretaceous birds. They are considered to contain the more advanced taxa of the Enantiornithes, the dominant group of birds during the late Mesozoic...
(Sanz et al. 1995). Its exact relationships, as with most enantiornithine birds, are unresolved however.