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Cranial and dental morphology in a bohaiornithid enantiornithine (1 Viewer)

Fred Ruhe

Well-known member
Netherlands
Di Liu. Luis M. Chiappe, Becky Wu, Qingjin Meng, Yuguang Zhang, Rui Qiu, Hai Xing & Zhaohui Zeng, in press

Cranial and dental morphology in a bohaiornithid enantiornithine with information on its tooth replacement pattern

Cretaceous Research. in press: Article 105021.
doi:10.1016/j.cretres.2021.105021

Abstract: Cranial and dental morphology in a bohaiornithid enantiornithine with information on its tooth replacement pattern

Despite the abundant number of enantiornithine fossils from the Jehol Biota, the cranial anatomy of these birds remains only superficially known. Similarly, data on dental replacement within this clade, and among toothed birds in general, is largely lacking. Here we describe a new and exquisitely preserved specimen of a bohaiornithid enantiornithine from the Lower Cretaceous Jiufotang Formation in Liaoning Province, northeastern China. The new specimen provides novel information on the cranial anatomy of these birds and unprecedented data on their tooth resorption, implantation, and replacement pattern, mostly visualized through computed laminography (CL) images. The new information demonstrates the presence of alternating tooth replacement with symmetrical signaling control, a pattern that is possibly shared by other enantiornithines. We also test the monophyly of Bohaiornithidae, one of the most species-rich groups of Jehol enantiornithines, through the addition of the new specimen. While our phylogenetic results support a monophyletic clade composed of several taxa traditionally included in this group (i.e., Bohaiornis, Sulcavis, Zhouornis, Longusunguis, and Parabohaiornis), it excludes Shenqiornis mengi, a species used to phylogenetically defined Bohaiornithidae. The fact that Shenqiornis is not resolved among the above-mentioned clade raises concerns about the usage of Bohaiornthidae as originally defined (i.e., most recent common ancestor of Shenqiornis mengi and Bohaiornis guoi, and all its descendants).

Enjoy,

Fred
 

Fred Ruhe

Well-known member
Netherlands
Figure 1. Full skeleton of BMNHC-Ph1204. Note that the patterns of cracks, the coloration of the slab, and the bone preservation indicates that entire left foot and the distal portion of the right foot (including all its digits) were added to the main slab by an unknown individual, an unfortunate common practice in Jehol fossils. The dark area at the bottom of the photograph and the portion of the feet highlighted in a lighter color indicate the portions added to the main slab. Abbreviations: co, coracoid; fe, femur; fi, fibula; fu, furcula; h, humerus; il, ilium; is, ischium; mc, metacarpus; mt, metatarsus; pc, pedal claw; pu, pubis; py, pygostyle; r, radius; sc, scapula; st, sternum; ti, tibia; u, ulna. Scale bar equals 10 mm.

Figure 2. Skull of BMNHC-Ph1204. A, photograph under normal illumination; B, interpretive drawing. Abbreviations: a, angular; af, antorbital fenestra; bc, basioccipital ; crl, caudal ramus of lachrymal; d, dentary; dpm, dorsal process of maxilla; e, exoccipital; f, frontal; fm, foramen magnum; fp, frontal process of premaxilla; j, jugal; hc, hypoglossal canal; hy, hyoid; la, lachrymal; mr, mandibular recess on surangular; mx, maxilla; n, nasal; na, external nares; nc, nuchal crest; oc, ophthalmic canal; p, parietal; pm, premaxilla; po, postorbital; q, quadrate; qj, quadratojugal; rrl, rostral ramus of lachrymal; s, scleral ossicles; sa, surangular; so, supraoccipital; sp, splenial; sq, squamosal. Darker gray boxes indicate the portions corresponding to the computer laminographies of Figure 4 and 5.
Scale bar equals 10 mm.

Fred
 

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