Pterodactylus? micronyx? TM 13104 (Winkler 1870, No. 34 in the Wellnhoger 1970 catalog) ~3 cm skull length, was considered a juvenile Pterodactylus, and Aurorazhdarcho, but it is unrelated. No. 34 was derived from a sister to Scaphognathus n110 and phylogenetically preceded another tiny pterosaur, the basal cycnorhamphid, BSP 1968 XV 132 and a larger pterosaur, the basal ornithocheirid, Gmu 10157.

Distinct from Scaphognathus, the skull of No. 34 had a shorter pointed rostrum. The postorbital was lower. The skull and mandible were more gracile with smaller teeth.

The entire vertebral spine was shorter and more gracile.

The sternal complex was anteroposteriorly shorter with distinct lateral processes. The metacarpus was longer, subequal to the ulna. The fingers were smaller. The proximal phalanges were longer.

The ischium was broad and its rims approach both the pubis and ilium. Metatarsal V was shorter. The metatarsals were not appressed.

One centimeter tall hatchlings might not have been volant due to their high surface-to-volume ratios. Instead they may have been restricted to humid leaf litter or risk desiccation (Hedges and Thomas 2001).

See the pterosaur family tree here.

Several correct and incorrect assignments to Pterodactylus. Click to enlarge. Many of these taxa (specimens) were assigned to the genus Pterodactylus by Wellnhofer (1970) and other authorities before the advent of computer assisted phylogenetic analysis and before most of them were graphically reconstructed and scaled to make comparisons easier. Furthermore, these assignments were made under the false assumption that pterosaurs, like mammals and archosaurus (including crocs and birds) changed as they matured, developing a relatively longer snout and smaller eye. Embryo pterosaurs demonstrate that relatively little changed during maturity, especially in the proportions of the skull.

Cycnorhamphus, its sisters and predecessors. Click to enlarge.

Hedges SB and Thomas R 2001. At the Lower Size Limit in Amniote Vertebrates: A New Diminutive Lizard from the West Indies. Caribbean Journal of Science 37:168–173.

Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.

Winkler TC 1870. Description d’un nouvel exemplaire de Pterodactylus micronyx du musee Teyler. Archives des Musee Teyler 3: 84-99.