Exploring the Ecomorphology of Two Cretaceous Enantiornithines With Unique Pedal Morphology

Abstract

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.

Animals, Plants and Afterimages: The Art and Science of Representing Extinction

“…He states that the Beothuk were regarded as 'vermin'. 87 Th is descriptor, suggesting the Beothuk were akin to a nuisance animal, positions them as similar in settler colonist eyes to the Newfoundland wolf. Th e great auk, by contrast, was not labelled as troublesome although the species did suff er from deleterious depictions, often being judged 'clumsy' and 'stupid'.…”

“…In a report on the topic of Indigenous knowledge as it links to extinction-related research, Audra Mitchell, Zoe Todd and Pitseolak Pfeifer draw attention to the way Western secular scientifi c logics continue to restrictively shape responses to the contemporary extinction crisis through entrenching divisions between human and 'nature', framing non-humans as resources for instrumental use and privileging technoscientifi c and economic management solutions to ecological crises. 87 Focusing on Canada's First Nations, Inuit and Métis communities, Mitchell, Todd and Pfeifer note that the turn to Indigenous knowledge to aid conservation initiatives is usually accompanied by a failure to recognize the distinct ontologies and epistemologies of the communities from which the insights are derived. Indigenous communities are mined for 'data' and then sidelined.…”

“…Th e Burmese enantiornithine Fortipesavis preserves soft tissue traces that indicate the presence of an unusually wide fourth pedal digit, 86 which may have increased stability while utilizing mobile purchases similar to the syndactyl foot in alcedinids (kingfi shers). 87 Soft tissue traces indicate that enantiornithines, like modern birds, laid a single egg at a time. 88 Preserved eggs and nests suggest at least some enantiornithines utilized breeding colonies that were situated near a source of water.…”

“…He co-authored (with Tammy Gordon) the book Tasmanian Tiger: Precious Little Remains, from which the exhibition of the same name was developed. 11, 73, 104, 145, 195, 318, 373, 378, 387, 393, 396, 408, 409, 410, 420n8; as abstraction 412; illustrations 410; as objectifi cation 412; and politics 80 Natural History Museum (London) 12, 304 natural sciences 38,68,73,87,88,217,171,172,173,174,177,179 New Zealand. See Aotearoa Newell,Norman 381 This open access edition has been made available under a CC BY-NC-ND 4.0 license thanks to the support of Knowledge Unlatched.…”

Reconstructing the dietary habits and trophic positions of the Longipterygidae (Aves: Enantiornithes) using neontological and comparative morphological methods

“…Morphologically and functionally similar features in extant taxa can provide data useful for constructing functional hypotheses and making niche predictions with regards to unique morphologies observed in extinct taxa ( Clark & O’Connor, 2021 ). Examples in paleontological literature include inferring aquatic habits for hesperornithiforms based on morphological similarities to the avian orders Anseriformes, Gaviiformes, Suliformes, and Podicipediformes ( Bell, Wu & Chiappe, 2019 ; Chinsamy, Martin & Dobson, 1998 ; Gingerich, 1973 ), reconstructing dietary habits of pterosaurs based on extant insectivorous and carnivorous dental morphologies ( Bestwick et al, 2018 ; Clark & Hone, 2022 ; Ősi 2011 ), and determining forelimb function in drepanosauromorphs using similar features observed in extant arboreal and fossorial taxa to demonstrate functional correlations ( Jenkins et al, 2020 ).…”