Rhamphorhynchus intermedius (Koh 1937) Late Jurassic ~155 mya, St/Ei 8209, No. 28 in the Wellnhofer 1975 catalog, is the most primitive Rhamphorhynchus specimen. It was derived from a sister to Campylognathoides liasicus and phylogenetically preceded the BMM specimen of Rhamphorhynchus. Note there is a phylogenetic size decrease series between the specimens. Precocious maturity and a smaller egg size are behind many of the observed changes. Campylognathoides did not survive into the Late Jurassic except through this lineage and Nesodactylus.
Distinct from the C. liasicus, the skull of R. intermedius was relatively larger with a smaller naris and antorbital fenestra. Only one maxillary tooth was enlarged to fang status and like the premaxillary teeth, it was procumbent. The mandible was robust and convex dorsally. Several anterior dentary teeth also leaned anteriorly.
The cervicals were slightly longer. The dorsal series was slightly shorter.
The scapula and coracoid were not fused. The deltopectoral crest was narrower. The ulna + radius was longer. The three distal wing phalanges were shorter and gracile.
The anterior prepubis appears to be decayed or the perforation is expanded leaving an anterior process and a ventral process above and below the former perforation. The hind limbs were among the shortest among pterosaurs. The pedal digits were shorter than the metatarsals and digit V was longer.
This specimen was considered a juvenile Rhamphorhychus by Bennett (1995), who used long bone measurements rather than a phylogenetic analysis.
See R. longiceps for size comparisons. See Campylognathoides C4 for a local family tree. |
