Almas ukhaa (Pei et al. 2017; Campanian, Late Cretaceous, IGM 100/1323) nests in the LRT as a basal anchiornithid, not a troodontid.

Sinovenator changii (Xu et al. 2002, IVPP V 12583; Late Jurassic) is a slender troodontid with a short rostrum and small hands, but a robust dorsal series. It is basal to the lineage that leads to birds.

Xiaotingia zhengi (Xu et al. 2011, STM 27-2; Late Jurassic) has a smile-like jawline and an upturned snout. The coracoids are longer and waisted, perhaps convergent with later birds. Such a coracoid is typically found in flapping tetrapods.

Eosinopteryx brevipenna (Godefroit et al. 2013, Middle-Late Jurassic, Tiaojishan Formation, YFGP-T5197, 30 cm, 12 in long) was a feathered theropod dinosaur. The forelimb feathers were quite long (Fig. 1), but the tail feathers were not. Note the short coracoid, not good for flapping. This taxon just precedes the appearance of the first bird Archaeopteryx and succeeds Aurornis.

Overall smaller, the snout was reduced. The cranium was broader. The naris was rotated dorsally. The coracoid was larger, not deeper. The pubis was shorter.

Ostromia crassipes (Foth and Rauhut 2017; Late Jurassic) reexamined the incomplete Haarlem specimen on plate and counter plate (TM 6928, 6929, Figs. 1–3) originally attributed to a pterosaur (Pterodactylus crassipes, von Meyer 1857) and later to Archaeopteryx crassipes (Ostrom 1970). The co-authors renamed the specimen Ostromia crassipes and nested it with Anchiornis (Fig. 2), a larger troodontid with a short coracoid outside of the bird clade in the large reptile tree (LRT). The authors employed a previously published phylogenetic analysis from Foth et al. 2014. which looked at the privately owned 11th specimen of Archaeopteryx. Unfortunately their cladogram lumped all Archaeopteryx specimens (Fig. 3) together. So we're dealing with a possible taxonomic chimaera and a certain taxon exclusion

Here Ostromia nests with Eosinopteryx in the proximal clade to the birds, starting with Archaeopteryx. Note the large claw on pedal digit 2 and the narrow but robust furcula.

TM = Teylers Museum in Haarlem, the Netherlands

Archaeopteryx albersdorfi (the Daiting specimen, SNSB BSPG VN-2010/1, Tischlinger 2009; Kundrát et al. 2018; Late Jurassic) was originally considered the 8th Archaeopteryx, but here nests basal to Xiaotingia and Eosinopteryx. The coracoids are still disc-like, indicating a lack of flapping.

Foth C and Rauhut OWM 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology 17:236

Godefroit P, Demuynck H, Dyke G, Hu D, Escuillié FO and Claeys P. 2013. Reduced plumage and flight ability of a new Jurassic paravian theropod from China. Nature Communications 4: 1394. doi:10.1038/ncomms2389

Kundrát M, Nudds J, Kear BP, Lü J-C and Ahlberg P 2018. The first specimen of Archaeopteryx from the Upper Jurassic Mörnsheim Formation of Germany. Historical Biology 31(1):3-63.

Pei R, Norell MA, Barta DE, Bever GS, Pittman M and Xu X 2017. Osteology of a New Late Cretaceous Troodontid Specimen from Ukhaa Tolgod, Ömnögovi Aimag, Mongolia PDF. American Museum Novitates. 3889: 1–47.

Shen C, Lü J, Liu S, Kundrát M, Brusatte SL and Gao H2017. A New Troodontid Dinosaur from the Lower Cretaceous Yixian Formation of Liaoning Province, China. PDFActa Geologica Sinica. 91 (3): 763–780. doi:10.1111/1755-6724.13307

Tischlinger H 2009. Der achte Archaeopteryx – das Daitinger Exemplar. Archaeopteryx. 27:1–20.

Xu X, Norell MA, Wang X-L, Makovicky PJ and Wu X-C 2002. A basal troodontid from the Early Cretaceous of China. Nature. 415: 780–784.

Xu X, You H, Du K and HanF-L 2011. An Archaeopteryx-like theropod from China and the origin of Avialae. Nature 475 (7357): 465–470.

wiki/Eosinopteryx
wiki/Xiaotingia
wiki/Sinovenator
wiki/Ostromia
wiki/Daliansaurus
wiki/Almas_ukhaa