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Anatomy of a new specimen of Piscivorenantiornis inusitatus (1 Viewer)

Fred Ruhe

Well-known member
Netherlands
Min Wang & Zhonghe Zhou, 2020

ANATOMY OF A NEW SPECIMEN OF PISCIVORENANTIORNIS INUSITATUS (AVES: ENANTIORNITHES) FROM THE LOWER CRETACEOUS JEHOL BIOTA

Journal of Vertebrate Paleontology. in press: e1783278.
doi:10.1080/02724634.2020.1783278

AbstractL https://www.tandfonline.com/doi/figure/10.1080/02724634.2020.1783278?scroll=top&needAccess=true

We describe a new enantiornithine specimen from the Lower Cretaceous Jiufotang Formation of the Jehol Biota, northeastern China, which can be assigned to the species Piscivorenantiornis inusitatus. The new specimen confirms the presence of the unusual articulation of the cervical vertebrae that characterizes P. inusitatus. The disarticulated bony elements in the new specimen, some of which are preserved in different views or completely missing from the holotype, enable a more comprehensive morphological reconstruction and a refined phylogenetic assessment of P. inusitatus. The new fossil demonstrates that the occipitals are recessed by a pair of fossae lateral to the foramen magnum, a feature otherwise unknown among Mesozoic and extant birds. Our phylogenetic analysis tentatively resolves P. inusitatus as the sister taxon to the clade consisting of Pterygornis dapingfangensis and Mirusavis parvus, which is recovered deeply nested within the Enantiornithes. We hypothesize that the craniolateral processes of the sternum are a derived feature in enantiornithines.

For the mpre details on this species see:

https://www.birdforum.net/showthread.php?t=342695&highlight

Enjoy,

Fred
 

Fred Ruhe

Well-known member
Netherlands
SYSTEMATIC PALEONTOLOGY

AVES Linnaeus, 1758
ORNITHOTHORACES Chiappe, 1995
ENANTIORNITHES Walker, 1981
PISCIVORENANTIORNIS INUSITATUS Wang and Zhou, 2017b

Holotype—IVPP V22582, a disarticulated, incomplete skeleton.

Referred Specimen—IVPP V23362, a disarticulated partially complete specimen preserved in a single slab (Fig. 1)

Locality and Horizon—Dapingfang Town, Sihedang Town, Lingyuan City, Chaoyang Country, Liaoning Province; Lower Cretaceous, Jiufotang Formation.

Revised Diagnosis—A small enantiornithine bird preserving the following autapomorphies: exoccipital bearing a pair of round fossae lateral to foramen magnum; premaxillary symphysis notched rostrally; cranial articular surface of caudal cervical vertebral centrum mediolaterally convex and dorsoventrally concave; and straight ventral margin of preacetabular process of ilium. Piscivorenantiornis inusitatus is further distinguishable from other enantiornithines based on the unique combination of following characters: sternum bearing a pair of craniolateral processes; coracoidal articular sulci widely spaced mediolaterally; lateral trabeculae of sternum bearing triangular caudal expansions that terminates level with the caudal end of the xiphoid process; minor metacarpal nearly straight; ilium bearing a large supracetabular tubercle medially; large pubic boot with recurved caudal tip; and medial condyle of metatarsal III trochlea more prominent than lateral condyle.

Fred

FIGURE 1. Piscivorenantiornis inusitatus, IVPP V22362, referred specimen. A, photograph and B, interpretative drawing. Abbreviations: at, atlas; a1, alular digit phalanx-1; cac, caudal cervical vertebra; cc, cranial cervical vertebra; de, dentary; fc, free caudal vertebra; fu, furcula; gs, gastralia; la, lacrimal; lc, left coracoid; lf, left femur; lfr, left frontal; lh, left humerus; lis, left ischium; lm, left carpometacarpus; lpb, left pubis; lq, left quadrate; lr, left radius; ls, left scapula; lsp, left splenial; lt, left tibiotarsus; lu, left ulna; m, right metatarsal I; m1, major digit phalanx 1; m2, major digit phalanx 2; mc, middle cervical vertebra; mi, minor metacarpal; op, occiput; pa, parietal; pi, pubis; pp, pedal non-ungual phalanx; pu, pedal ungual phalanx; py, pygostyle; ra, radiale; rb, rib; rc, right coracoid; rf, right femur; rfr, right frontal; rh, right humerus; ril, left ilium; ris, right ischium; rm, right postdentary mandible; rpb, right pubis; rq, right quadrate; rr, right radius; rs, right scapula; rsp, right splenial; rt, right tibiotarsus; rtm, right tarsometatarsus; ru, right ulna; sn, synsacrum; st, sternum; te, tooth; tv, thoracic vertebra; uc, uncinate process; ul, ulnare.
Scale bar equals 10 mm.
 

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Fred Ruhe

Well-known member
Netherlands
FIGURE 2. Interrelationships of enantiornithine birds.A, enantiornithine portion of strict consensus tree recovered from current phylogenetic analysis, based on additional information from the new referred specimen of Piscivorenantiornis inusitatus. The complete strict consensus tree is available as Figure S1 in Supplemental Data 1. B, enantiornithine portion of reduced consensus with the most unstable taxa excluded from the consensus (placements of other non-enantiornithines are the same as in the strict consensus).

Fred
 

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