Sinosauropteryx
Three specimens have been assigned to "Sinosauropteryx prima": the holotype GMV 2123 (and its counter slab [opposite face], NIGP 127586), NIGP 127587, and D 2141. Another specimen, IVPP V14202, was assigned to the genus but not to the only species by Zhang and colleagues. The assignment of an additional larger specimen to "S. prima", GMV 2124, was later found to be in error. All of the fossils were found in the Jianshangou or Dawangzhangzi Beds of the Yixian Formation in the Beipiao and Lingyuan regions of Liaoning, China. These fossil beds have been dated to 124.6–122 million years ago, during the early Aptian stage of the Early Cretaceous.
Siroccopteryx
This pterosaur is known only from the front part of the jaw with teeth. The holotype fossil, LINHM 016 (Long Island Natural History Museum), was found near Ksar es Souk, in the province of Errachidia in the region of Meknes-Tafilalet at 30.4 ° N, 4.9 ° longitude (17.6 ° N, 4.2 ° W longitude) in Beg'aa, west of Hamada du Guiren in southeastern Morocco, in a layer of red sandstone, a fine-grained alluvium from the Albian-Cenomanian. It consists of front teeth and a snout that not compressed. The muzzle was long and narrow, with a large elongated terminal part, with a sort of shaped crest anterior keel highest that of "Anhanguera" but not as high as that of "Coloborhynchus" or "Tropeognathus". The teeth were sharp but short and more robust than in "Anhanguera". The bone is rough and leathery, with strange marks of wrinkles and depressions, this may be a consequence of the conditions of preservation, but the descriptors suggest that indicate a disease, possibly caused by dental abscesses. According to André Veldmeijer, is probably that this damage was post-mortem and indicate the presence of a horn cover in the ridge.