Baminornis zhenghensis

choi

(1) Chen RS et al, Earliest Short-Tailed Bird from the Late Jurassic of China. Nature, 638: 441 (Feb 12, 2025)
https://www.nature.com/articles/s41586-024-08410-z
(Abstract: "the unquestionable Jurassic bird fossil record is limited to Archaeopteryx * * * Although they have feathered wings, the known Jurassic birds are more similar to non-avialan theropods in having the ancestral long reptilian tail9-11. This is in stark contrast to most Cretaceous and crownward taxa, which have a short tail that terminates in a compound bone called the pygostyle")

Note: This report is locked behind paywall. Min WANG is the corresponding author.

(2) Liyan Qi, Newly Discovered Fossil Reveals the Oldest Known Bird; A find in China suggests avians evolved millions of years earlier than had been thought. Wall Street Journal, Mar 1, 2028, at page C3 (every Saturday, section C is Review).
https://www.wsj.com/science/dino ... -discovery-806d5f62


(3) Jurassic Fossil Discovery in East China Sheds New Light on Origin of Birds. Xinhua, Feb 13, 2025 ("update" on the same day of the original publication).
https://english.news.cn/20250213 ... 8de068a0cd0c/c.html

Note:
(a) "The fossilized bird Baminornis zhenghensis was discovered in Zhenghe County, Fujian Province [福建省南平市 政和县]. Its short tail ends in a compound bone called the pygostyle, a feature uniquely present in modern birds. This indicates that the body structure of modern birds emerged in the Late Jurassic Period, 20 million years earlier than previously known."
(i) Baminornis
https://en.wikipedia.org/wiki/Baminornis
( "(meaning 'Fujian Province bird') * * * was discovered in outcrops of the Nanyuan Formation [(地层 南园组] ('layer 2') near Yangyuan Village of Zhenghe County [政和县杨源乡 杨源村] in Fujian Province" )
(A) For "Bamin," see 福建省
https://zh.wikipedia.org/zh-cn/福建省
(section 1 名称: 八閩)
(B) English dictionary:
* ornithology (n; from Ancient Greek [noun masculine or feminine] ὄρνις ([romanization:] órnis) bird + [noun masculine] λόγος (lógos) [word])
https://en.wiktionary.org/wiki/ornithology
(ii) pygostyle (n; from Ancient Greek [noun feminine] πυγή ([romanization:] pugḗ) tail, rump + στῦλος (stûlos) column)
https://en.wiktionary.org/wiki/pygostyle
(pronunciation)

So called tail column, because it is a column (shape) in the tail (of a bird).

(b) The pygostyle will be explored further here.
(i)
(A) All mammals, from whale to human, have 7 cervical vertebrae, 12 thoracic vertebrae (each with a pair of ribs), 5 lumbar vertebrae, 1 each of both sacrum and coccyx.
• "This elongation [of neck] largely takes place after birth, perhaps because giraffe mothers would have a difficult time giving birth to young with the same neck proportions as adults."  en.wikipedia.org for Giraffe.
• Different bird species have different numbers of vertebrae.
(B) bird anatomy
https://en.wikipedia.org/wiki/Bird_anatomy
, where a sketch displays the caption: "Diagram of a general bird pelvic girdle skeleton including the lower vertebral column sections. Note that the caudal vertebrae (5–10) are not fused in this diagram but can be in certain species [bird head is to the left]." To the right of this sketch is text in section 1 Skeletal system, section 1.1 Axial skeleton, section 1.1.1 Vertebral column, section 1.1.1.3 Synsacrum + section 1.1.1.4 Caudal vertebrae)
• The axial skeleton includes the bones of the skull, spine, and ribcage.
• section 1.1.1.3 Synsacrum: "The synsacrum consists of one thoracic, six lumbar, two sacral, and five sacro-caudal vertebrae fused into one ossified structure"

synsacrum
https://en.wikipedia.org/wiki/Synsacrum
(the green bar in top right illustration)
(C) What is the function of pygostyle in a modern bird? Muscles are attached to a pygostyle to move the tail feathers up or down, and sidewise.

Xie HL et al, Design and Kinematic Analysis of Deployable Antenna for Bionic Bird Tail Feather. Applied Sciences, 13: 12598 (2023; in a special issue "Antenna: Design Methodology, Optimization, and Technologies")
https://www.mdpi.com/2076-3417/13/23/12598
("Figure 6. Muscle structure of bird tail. (a) Top view of pigeon tail morphology. (b) Left view of pigeon tail morphology.")

In Fig 6(b), the bird head is to the right (because ilium is pointing to the head).
Baumel J et al, The Ventilatory Movements of the Avian Pelvis and Tail: Function of the Muscles of the Tail Region of the Pigeon (Columba livia). Journal of Experimental Biology, 151: 263 (1990)
https://www.semanticscholar.org/ ... 3432cc4afb43d68a5e1
(Figure 1 (top view) amd Figure 2 (caudal view of the muscles that move tail: these muscles, generally speaking, are attached to pygostyle) )
(ii) Here is an inventory of the muscles in a bird tail: Musculi Caudae et Cloacae - Annotations. Ogden, Utah: Weber State University, undated.
https://www.weber.edu/NAA/TailMmAnnotations.html
( (65)  M. levator caudae + M. lateralis caudae + M. depressor caudae (66)  M. pubocaudalis externus; M. pubocaudalis internus; M. caudofemoralis, pars caudalis (67)  M. bulbi rectricium; M. adductor rectricium +(68) Musculi cloacales; M. sphincter cloacae; M. transversus cloacae;
Septum supracloacale)

The m stands for Latin noun masculine musculus muscle. M or m levator caudae is the Latin name for a muscle; in the second half of the 29th century, anatomy textbooks written in English moved gradually to anglicize jargon (such as names of bones and muscles) so that word modifier omes BEFORE the muscle or bone.  

(c) "Wang Min [王敏 (male); 中国科学院研究生院,古生物与地层学专业,博士 (2009-2014)], a researcher with the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) [古脊椎动物与古人类研究所] under the Chinese Academy of Sciences (CAS), and the leading scientist of the research team. * * * Zhou Zhonghe [周忠和, a co-author of the Nature article], an academician of CAS."
(d) Underneath the fossil is a sketch of the fossil, both were published in the Nature article. The sketch is not provided with the keys. But, from the right to left: pu=pubis 耻骨, is=ischium 坐骨, ?is=the other ischium?, pg=pygostyle (you see, the dinosaur/bird was crushed when fossilized, and the tail was pointing to the left, whereas the body pointing to the left (where the head would be, but is now missing); (between the body and one (not two) clawed wing) is ?ul=an ulna?; sc=scapula (肩胛; bird's is a long bone, and looks different from human's), caIII=the third carpal bone (a bone in the wrist joint; 腕骨); mcI, II, III=metacarpal bones I to III (in humans, metacarpal bones are in the palm), the first finger is PI-1 and 2 (P stands for phalznx), the second finger is PII-1 and 2 etc).
(e)
(i) This new find is compared to Archaeopteryx
https://en.wikipedia.org/wiki/Archaeopteryx
("Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest known bird (member of the group Avialae).[2] Older potential avialans have since been identified, including Anchiornis, Xiaotingia, Aurornis,[3] and Baminornis zhenghensis. * * * Archaeopteryx had more in common with other small Mesozoic dinosaurs than with modern birds. In particular, they shared the following features with the dromaeosaurids and troodontids: jaws with sharp teeth, three fingers with claws, a long bony tail * * *  ")
is a genus whose various fossils have been found.
(ii) Xiaotingia
https://en.wikipedia.org/wiki/Xiaotingia
(About Xiaotingia zhengi: "The generic name and specific name together honour paleontologist Zheng Xiaoting" 郑晓廷 (male; 1954- ; 临沂大学) )

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I published the above on Mar 6, 2025.

In Note (c), I wrote, "sc=scapula (肩胛; bird's is a long bone, and looks different from human's)."

Rather, sc=scaphoid (one of the wrist bones), not scapula.
• English dictionary:
* scaphoid (n; Ancient Greek [noun feminine] σκᾰ́φη ([romanization:] skắphē, boat + English suffix -oid)
https://en.wiktionary.org/wiki/scaphoid

The bone is boat-like in shape, because both ends of the bone rise up (like a 元宝).
* carpus (n; from Latin noun masculine of the same spelling and meaning wrist, in turn from Ancient Greek [noun masculine] καρπός ([romanization:] karpós, wrist): "(anatomy) the group of bones that make up the wrist"
https://en.wiktionary.org/wiki/carpus
• carpal bones [of a human]
https://en.wikipedia.org/wiki/Carpal_bones
(scaphoid)