[dinosaur] Avian footpad scales + big Paleocene penguin from New Zealand + snakebird evolution

Ben Creisler
[email protected]

Some recent avian papers:

Free pdf:

Rory L. Cooper, Victoria J. Lloyd, Nicolas Di-Poï, Alexander G. Fletcher,
Paul M. Barrett & Gareth J. Fraser  (2019)
Conserved gene signalling and a derived patterning mechanism underlie the
development of avian footpad scales.
EvoDevo 10, Article number: 19
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1186_s13227-2D019-2D0130-2D9&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=gRr12tct5ZU1T_zaa7nYf6_Kka_4gFNEDGAUoFhxx5I&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__evodevojournal.biomedcentral.com_articles_10.1186_s13227-2D019-2D0130-2D9&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=AzhIS58khO-iUtWm5ERnegZkcU0KIPKOSGT_JrgXikk&e= 

Free pdf:
https://urldefense.proofpoint.com/v2/url?u=https-3A__evodevojournal.biomedcentral.com_track_pdf_10.1186_s13227-2D019-2D0130-2D9&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=ebrxALPMSR5WTR-yPH1bwYBjQD5jF4zDj7ug6wJQgNs&e= 


Background
Vertebrates possess a diverse range of integumentary epithelial appendages,
including scales, feathers and hair. These structures share extensive early
developmental homology, as they mostly originate from a conserved
anatomical placode. In the context of avian epithelial appendages, feathers
and scutate scales are known to develop from an anatomical placode.
However, our understanding of avian reticulate (footpad) scale development
remains unclear.

Results
Here, we demonstrate that reticulate scales develop from restricted
circular domains of thickened epithelium, with localised conserved gene
expression in both the epithelium and underlying mesenchyme. These domains
constitute either anatomical placodes, or circular initiatory fields
(comparable to the avian feather tract). Subsequent patterning of
reticulate scales is consistent with reaction–diffusion (RD) simulation,
whereby this primary domain subdivides into smaller secondary units, which
produce individual scales. In contrast, the footpad scales of a squamate
model (the bearded dragon, Pogona vitticeps) develop synchronously across
the ventral footpad surface.

Conclusions
Widely conserved gene signalling underlies the initial development of avian
reticulate scales. However, their subsequent patterning is distinct from
the footpad scale patterning of a squamate model, and the feather and
scutate scale patterning of birds. Therefore, we suggest reticulate scales
are a comparatively derived epithelial appendage, patterned through a
modified RD system.

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?Crossvallia waiparensis, sp. nov.

Gerald Mayr, Vanesa L. De Pietri, Leigh Love, Al Mannering & R. Paul
Scofield (2019)
Leg bones of a new penguin species from the Waipara Greensand add to the
diversity of very large-sized Sphenisciformes in the Paleocene of New
Zealand.
Alcheringa (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1080_03115518.2019.1641619&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=_T_MRDpQs4xOf5aOncRPDHkbfq0QH745QTYks37GTx8&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.tandfonline.com_doi_full_10.1080_03115518.2019.1641619&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=Ax4DWX5WSek_YhTxYyqyvk56cM-VPB_h_dgFlvAfyUU&e= 


We describe a new large-sized species of the Sphenisciformes (penguins)
from Paleocene strata of the Waipara Greensand in New Zealand. ?Crossvallia
waiparensis, sp. nov. is represented by leg bones of a single individual as
well as two tentatively referred proximal humeri and resembles Crossvallia
unienwillia from the late Paleocene of Antarctica in size and morphology.
The new species is the fifth published species of stem group
Sphenisciformes from the Waipara Greensand and the fourth one, which has
been formally named. It is distinguished from a recently reported
tarsometatarsus of an unnamed large-sized penguin species from the Waipara
Greensand and is the oldest well-represented giant penguin. ?C. waiparensis
approaches the size of the Eocene taxa Anthropornis and Palaeeudyptes and
provides further evidence that penguins attained a very large size early in
their evolutionary history.

===


Martyn Kennedy,  Sampath S. Seneviratne,  Ushawarni K. Mendis  & Hamish G.
Spencer (2019)
Sorting out the Snakebirds: The species status, phylogeny, and biogeography
of the Darters (Aves: Anhingidae).
Journal of Zoological Systematics and Evolutionary Research (advance online
publication)
doi:  https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1111_jzs.12299&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=wZVfKPa8I-tr_7IxZvlAKEblr4_vKb8S1jQZIIr5Dyc&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__onlinelibrary.wiley.com_doi_10.1111_jzs.12299&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=4t8o_n1pwNNWoXDaHWX1IUmThjAwlUuhkhdP6AIkoow&e= 


Although the avian family Anhingidae is unequivocally monophyletic, the
number and relationships of the component species within the single genus
(Anhinga) have long remained unclear. Here, we use extensive mitochondrial
and nuclear DNA sequence data (8,878 bp) to show that four species should
be recognized. Our fully resolved and well‐supported tree shows that the
American Anhinga (Anhinga anhinga) is sister to the three Old World
species, with the Oriental (A. melanogaster) and African (A. rufa) Darters
sister within the Old World clade, which also includes the Australian
Darter (A. novaehollandiae). We estimate that the divergence between the
New World and Old World branches occurred 19-22 mya, with the Australian
Darter separating from its Old World congeners 14-16 mya and the Oriental
and African species splitting ~10 mya. The genus is yet another example of
osteological conservatism in the Suliformes, which is comparable to that
shown by the cormorants and shags. Nevertheless, the relationships we infer
are congruent with recent plumage studies and are biogeographically
plausible. We suggest that further investigation of the variation within
the African and Australian Darters would be of interest.


======

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Also may be of interest:

Free pdf:

Esteban Fernández-Juricic,  Patrice E. Baumhardt,  Luke P. Tyrrell,  Amanda
Elmore,  Shelagh T. DeLiberto & Scott J. Werner (2019)
Vision in an abundant North American bird: The Red-winged Blackbird.
The Auk: ukz039 (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1093_auk_ukz039&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=Qt60jWiBsErAo1l3p4RZ_gGUfD4Ycu2gvShcO_mtb9o&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__academic.oup.com_auk_advance-2Darticle_doi_10.1093_auk_ukz039_5549081&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=N-uVURe2V7jSW6h2fHRM37BPkYajwdGUwArhNAk0J7w&s=FM-m_baBhvFj0HqBbWdBkKk4YJ8ubockU94L6yitc88&e= 

Avian vision is fundamentally different from human vision; however, even
within birds there are substantial between-species differences in visual
perception in terms of visual acuity, visual coverage, and color vision.
However, there are not many species that have all these visual traits
described, which can constrain our ability to study the evolution of visual
systems in birds. To start addressing this gap, we characterized multiple
traits of the visual system (visual coverage, visual acuity, centers of
acute vision, and color vision) of the Red-winged Blackbird (Agelaius
phoeniceus), one of the most abundant and studied birds in North America.
We found that Red-winged Blackbirds have: wide visual coverage; one center
of acute vision per eye (fovea) projecting fronto-laterally with high
density of single and double cones, making it the center of both chromatic
and achromatic vision; a wide binocular field that does not have the input
of the centers of acute vision; and an ultraviolet sensitive visual system.
With this information, we parameterized a Red-winged Blackbird-specific
perceptual model considering different plumage patches. We found that the
male red epaulet was chromatically conspicuous but with minimal achromatic
signal, but the male yellow patch had a lower chromatic but a higher
achromatic signal, which may be explained by the pigment composition of the
feathers. However, the female epaulet was not visually conspicuous in both
the chromatic and achromatic dimensions compared with other female feather
patches. We discuss the implications of this visual system configuration
relative to the foraging, antipredator, mate choice, and social behaviors
of Red-winged Blackbirds. Our findings can be used for comparative studies
as well as for making more species-specific predictions about different
visual behaviors for future empirical testing.

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