These specimens were all attributed to Darwinopterus modularis. Above: the holotype, ZMNH M8782. Below left: the female "Mrs. T" AMNH M8802. At lower right: YH-2000. The variation here goes beyond gender. These are distinct species (see D. robustodens below). The pelvic opening is not larger in the female and that was never documented with comparative studies. The ischium was actually deeper in ZMNH M8782, the crested, supposedly "male" specimen. Currently there is no way to determine gender in pterosaurs other than with an egg preserved between the legs.

Darwinopterus modularis ZMNH M8782 (Lü et al. 2009) Middle Jurassic was originally considered the transitional taxon linking long-tailed rhamphorhynchoid-grade pterosaurs to pterodactyloid-grade pterosaurs. Unfortunately the cladistic analysis was flawed by not including enough pterosaurs to compare it with and by accepting the resulting 500,000+ possible trees. Here a resolved tree was produced using many times more taxa. Derived from a sister to Pterorhynchus and Kunpengopterus, Darwinopterus was a sister to Wukongopterus and these two left no known descendants.

Distinct from Kunpengopterus, the skull of the Darwinopterus holotype (ZMNH M8782) was relatively larger and had a straighter, more robust rostrum with a short bony crest that likely served as the base for a soft crest, as seen in Pterorhynchus. The teeth were larger.

Distinct from Kungopterus, the sternal complex of YH-2000 was triangular, as in Pterorhynchus, but much smaller. The anterior process of the prepubis was deeper. Pedal 5.2 was bent, not curved.

The Lü et al. (2009) paper introducing Darwinopterus included two major problems: 1) the false tradition that the Pterodactyloidea was a monophyletic taxon with a single basalmost taxon, 2) the adoption of the false hypothesis of "modular evolution" in which the skull as a whole could develop derived characters while the post-crania remained primitive. Darwinopterus was paraded as a transitional taxon, but actually it is a fairly typical long-tailed scaphognathian pterosaur with a long neck and lacking a distinct naris. Both of these traits are similar to those found in Pterorhynchus.

Size comparisons between wukongopterids are here. The expanded family tree of the Pterosauria is here.