• BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

    Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

Fortipesavis prehendens gen. et sp. nov. (1 Viewer)

Fred Ruhe

Well-known member
Netherlands
Alexander D. Clark & Jingmai O'Connor, 2021

Exploring the Ecomorphology of Two Cretaceous Enantiornithines With Unique Pedal Morphology

Frontiers in Ecology and Evolution. 9: Article 654156.
doi:10.3389/fevo.2021.654156

Abstract and full text: Exploring the Ecomorphology of Two Cretaceous Enantiornithines With Unique Pedal Morphology

Recently, ∼100 Ma amber from Myanmar has become an important source of information regarding the morphology of Late Cretaceous enantiornithines. Two specimens consisting of partial hindlimbs exhibit unusual morphologies when compared to both extant avian taxa and other Cretaceous enantiornithines. Pedal morphology is extremely ecologically informative in Aves as it represents the interface between body and substrate. These seemingly bizarre pedal morphologies represent adaptations that allowed these birds to utilize certain niches present in their paleoenvironment. Specific ecological niches apply the same general pressures to different species over time, and in doing so, through natural selection, produce morphologies that function much the same, although they may be anatomically dissimilar. As such, extant animals can provide useful information pertaining to the functional morphology of extinct animals, even in the absence of direct analogs, as in the case of these two Hukawng enantiornithines. Comparisons to extant taxa in the same predicted niches of these enantiornithines can be used to either support or contradict previous hypotheses regarding the in vivo function of these unique pedal morphologies. Elektorornis chenguangi exhibits a hypertrophied third pedal digit, originally interpreted as an appendage used for probing. We support this interpretation, which allows informed speculation as to the cranial anatomy of this taxon since extant animals that probe in woody substrates consistently pair elongate probing structures with a second robust structure that functions as a means to penetrate into this hard substrate. This suggests that the rostrum of Elektorornis would have been robust and most likely edentulous. The second specimen YLSNHM01001 exhibits an unusually mediolaterally robust fourth pedal digit, nearly double the width of digit II. Given that no such morphology is present in any other bird in the Mesozoic or Cenozoic we feel the unusual morphology justifies erection of a new taxon, Fortipesavis prehendens gen. et sp. nov. Although distinct, the morphology in F. prehendens resembles the syndactyl condition in some extant avian groups, and we hypothesize the robust digit similarly functioned to increase the surface area of the foot, facilitating grip on perches through increased friction. The necessity for increased grip and the lateral placement of this digit may suggest F. prehendens utilized mobile perches similar to extant kingfishers.

Enjoy,

Fred
 
Last edited:

Fred Ruhe

Well-known member
Netherlands
Systematic Paleontology

Aves Linnaeus 1758
Ornithothoraces Chiappe, 1995
Enantiornithines Walker, 1981

Fortipesavis prehendens gen. et sp. nov.

Holotype​

YLSNHM01001, external mold of digits II–IV and distalmost portion of left tarsometatarsus preserved in amber.

Etymology​

The generic name Fortipesavis, derives from “Fortipes, Latin compound for strong-footed, “avis,” Latin meaning bird. The specific name “prehendens” comes from the Latin verb to grip or grasp. “Fortipesavis prehendens, Latin for gripping strong-footed bird.

Diagnosis​

Small bird with the unique combination of the following features: mediolateral width of digit IV greater than digit III, and that of digit III greater than that of digit II, such that the mediolateral width of digit IV is twice that of digit II (autapomorphy); plantar pads of digit IV mediolaterally wider than they are craniocaudally long and located between phalangeal joints; exaggerated plantar pads of digit IV separated by deep clefts; and digit II ungual long, recurved and sharply tapered.

Age​

Latye Cretaceous, Middle-upper Albian, 98.8 ± 0.06 Ma.

Fred


Figure 1:
The external surface of the partial left pes of YLSNHM01001 in (A) medial, (B) ventral, and (C) dorsal views. Note digit I (hallux) is missing from the specimen but is assumed to be a feature based on known enantiornithine pedal morphology. Scale bars = 5 mm, (A–C)
 

Attachments

  • Fortipesavis.jpg
    Fortipesavis.jpg
    319.8 KB · Views: 1
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia
ZEISS. Discover the fascinating world of birds, and win a birding trip to Columbia

Users who are viewing this thread

Top