Navalón et al. 2017
report on “the earliest representative of the clade” Confuciusornithidae, a bird clade known from hundreds of Early Cretaceous specimens of the genus Confuciusornis (Fig. 1), first reported by Hou et al. 1995. Highlights (= summary) and partial abstract copied below, but the gist is: they found an early Cretaceous confuciusornithid earlier than than other confuciusornithids, but not early enough…
the Navalón team did not expand their taxon list sufficiently. They should have looked at one of the Solnhofen birds, Wellnhoferia (Fig. 1). It is the earliest known representative of the clade Confuciusornithidae in the present study.
Wellnhoferia (Late Jurassic, Fig. 1) is one of the Solnhofen birds traditionally considered Archaeopteryx (the Solnhofen specimen, or no. 6). It was initially misidentified as Compsognathus and kept in a private collection. Peter Wellnhofer re-identified the specimen as the 6th Archaeopteryx (Wellnhofer 1988a,b). Elzanowski (2001) thought the specimen was generically distinct from the type, so renamed it Wellnhoferia, to honor Wellnhofer.
Elzanowski 2001 reported
the 6th specimen differed from Archaeopteryx in having:
- a short tail (16-17 causals)
- a nearly symmetrical pattern of pedal rays (toes) 2–4 with metatarsals 2 and 4 of equal length and digit 4 substantially shorter than in Archaeopteryx with only 4 phalanges
- large size and details of the pelvic limb are different.
Prior workers overlooked
the circular hole in the proximal humerus, a trait shared with confuciusornids, but not scored in the large reptile tree (LRT, 1122 taxa). Confuciusornis and Welllnhoferia nest together in the LRT and apart from most other Solnhofen birds, including the type of Archaeopteryx. Zhongornis is the outgroup taxon for Confuciusornithids in the LRT.
Mayr et al. (including some guy other than me named D. Peters) 2007 described the tenth Solnhofen bird and did not recognize that Wellnhoferia was distinct from Archaeopteryx. Senter and Robins 2003 supported Elzanowski (2001).
Highlights from Navalón et al. 2017.
“We describe an adult specimen of a confuciusornithid bird from the Huajiying Formation of the Jehol Biota, which contains the earliest representatives of the clade. The new fossil is most similar to the synchronic but immature Eoconfuciusornis zhengi, supporting the validity of the latter taxon. The confuciusornithids from the early (Huajiying Formation) and late (Yixian Formation and Jiufotang Formation) Jehol Biota are morphologically distinct from each other.”
“The Huajiying Formation contains the earliest deposits of the Jehol Biota, representing the world’s second oldest (after Solnhofen) avifauna. This avifauna includes the early confuciusornithid Eoconfuciusornis zhengi, the oldest occurrence of this clade and one of the earliest divergences of pygostylian birds. Although E. zhengi shows unique traits, the holotype’s immature age makes comparisons with the better known Confuciusornis sanctus problematic. As a result, the taxonomic validity of E. zhengi is controversial. We describe a small, osteologically adult confuciusornithid from the same deposits as E. zhengi. The new fossil is most similar to E. zhengi but also shares traits with the stratigraphically younger Confuciusornis. The humerus of the new fossil is straighter and more slender, and bears a less dorsally-developed deltopectoral crest compared with similarly-sized and smaller specimens of Confuciusornis. The morphology of the humerus is intermediate between E. zhengi and Confuciusornis and its proximal portion is pierced by a small deltopectoral foramen, absent in the holotype of E. zhengi. However, this foramen is much smaller than in any other confuciusornithid.”
from this blogpost repeats an earlier hypothesis: The initial radiation of birds preceded the Late Jurassic. Solnhofen birds, few of which are congeneric, represent that a wide gamut of taxa, each a representative from that earlier initial radiation.
On a side note
Madagascar separated from Africa 160 million years ago, ten million years prior to the Solnhofen formation and the Solnhofen birds that are found there. On the African side of the split were the ancestors of the ostrich, Struthio. On the Madagascar side were the ancestors of the elephant bird, Aepyornis.
Elzanowski A. 2001. A new genus and species for the largest specimen of Archaeopteryx. Acta Palaeontologica Polonica 46(4):519–532.
Hou L, Zhou Z, Gu Y and Zhang H 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin 40: 1545–1551.
Mayr G, Pohl B, Hartman S and Peters DS 2007. The tenth skeletal specimen of Archaeopteryx. Zoological Journal of the Linnean Society. 149 (1): 97–116.
Navalón G, Meng Q-G, Marugán-Lobón J, Zhang Y, Wang B-P, Xing H, Liu D and Chiappe LM 2017. Diversity and evolution of the Confuciusornithidae: Evidence from a new 131-million-year-old specimen from the Huajiying Formation in NE China. Journal of Asian Earth Sciences (advance online publication)
Senter P and Robins JH 2003. Taxonomic status of the specimens of Archaeopteryx. Journal of Vertebrate Paleontology 23(4):961–965.
Wellnhofer P 1988. A New Specimen of Archaeopteryx. Science 240(4860):1790–1790.