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| Chromeornis funkyi O’Connor, Wang, Clark, Kuo, Davila, Wang, Zheng & Zhou, 2025 Artwork: Sunny Dror |
ABSTRACT
The Longipterygidae are a diverse group of small to medium sized enantiornithine birds with elongate rostra and distally restricted dentition known from the Early Cretaceous Jehol Lagerstätten. The largest taxon, Longipteryx, is known from dozens of specimens but comparatively little is known about small-bodied taxa, sometimes resolved in a subclade, the Longirostravinae. Here we describe a small longipterygid representing a new taxon, Chromeornis funkyi gen. et sp. nov., with a combination of features present in longirostravines and Longipteryx. Cladistic analysis indicates the new species is a member of the Longipteryginae, more closely related to Longipteryx than other longipterygids. The specimen preserves extensive soft tissue including traces of the eyes, skin, and feathers, as well as an unusual mass of gastroliths preserved appressed against the left lateral margin of the cervical vertebrae. Computed-tomography based comparison with the in situ gastric mill preserved in the sympatric ornithuromorphs Archaeorhynchus and Iteravis strongly suggests these gastroliths are not gizzard stones. The absence of a gastric mill in enantiornithines is consistent with pectoral girdle morphology that indicates limited flight capabilities in Early Cretaceous species suggesting ground take off, a necessity of collecting stones, was energetically costly compared to ornithuromorphs. Increases in body mass due to a large gastric mill may have further impeded volant locomotion resulting in a low cost-benefit tradeoff such that this structure was unlikely to evolve during early enantiornithine evolution.
Keywords: Longipterygidae; new genus; new species; Jehol Biota; regurgitalite; gastrolith; Aves; Avialae.
Class AVES Linnaeus 1758
Clade ORNITHOTHORACES Chiappe 1995
Clade ENANTIORNITHES Walker 1981
Family LONGIPTERYGIDAE Zhang et al. 2000
Chromeornis funkyi gen. et sp. nov.
Etymology. Funky Chromeo bird, in honor of the Chromeo Funklordz P-Thugg and Dave 1, who like many birds, make beautiful music. Pronounced crow-me-OR-niss funk-e e.
Diagnosis. A small (estimated 33.5 g) longipterygid (rostrum ~60% of the skull or greater, distally restricted dentition, premaxillary corpus with elongate imperforate rostral end with parallel dorsal and ventral margins, robust pygostyle longer than tarsometatarsus, coracoid with straight lateral margin, humerus with narrow deltopectoral crest) enantiornithine (cranially forked pygostyle with ventrolateral processes, Y-shaped furcula with dorsally excavated rami, proximal humerus with small convex humeral head separated from the dorsal and ventral tubercles by concavities, minor metacarpal projecting farther distally than the major metacarpal, metatarsal IV reduced) distinguishable by the unique combination of the following characters: dentary straight; sternum with slightly splayed lateral trabeculae with asymmetrical fan-shaped distal expansions and short, straight intermediate trabeculae; hand shorter than humerus; alular digit short with small claw; second phalanx of major digit half the length of first phalanx; femur straight.
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| Photographs of the counter slab of Chromeornis funkyi gen. et sp. nov. STM7-156. Scale bars equal one centimeter. preserved with over 800 tiny rocks in its throat (visible as the gray mass next to the left of its neck bones). |
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| Close-up of the mass of rocks in the throat of Chromeornis (the rocks are the gray mass just to the left of the neck bones). |
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| An illustration showing Chromeornis funkyi gen. et sp. nov. in life. Artwork: Sunny Dror |
Jingmai O’Connor, Xiaoli Wang, Alexander Clark, Pei-Chen Kuo, Ryan Davila, Yan Wang, Xiaoting Zheng, and Zhonghe Zhou. 2025. A new small-bodied longipterygid (Aves: Enantiornithes) from the Aptian Jiufotang Formation preserving unusual gastroliths. Palaeontologia Electronica. 28(3):a56. DOI: doi.org/10.26879/1589
palaeo-electronica.org/content/2025/5712-longipterygid-enantiornithine-chromeornis
https://palaeo-electronica.org/content/current-in-press-articles/5713-longipterygid-enantiornithine-chromeornis