Aurorazhdarcho: a small pterosaur from the Solnhofen lagoons

Aurorazhdarcho is a small pterodactyloid pterosaur known from the Late Jurassic lithographic limestones of Bavaria. Its best-known specimen, NMB Sh 110, preserves nearly the entire postcranial skeleton, but not the skull or neck. The genus is closely tied to the older name Pterodactylus micronyx, and researchers have revised both its synonymy and its place among pterosaurs.

It belongs in the pterosaur catalogue as a case where a well-preserved body and a difficult specimen history answer different questions.

Quick facts

A new genus from an old quarry

In 1998, private collector Peter Katschmekat found the slab now catalogued as NMB Sh 110 in the public Blumenberg Quarry, about three kilometres north-west of Eichstätt. Gerd Stübener prepared it. Eberhard Frey, Christian A. Meyer and Helmut Tischlinger described it in 2011 as the new genus and species Aurorazhdarcho primordius. The specimen is held by the Natural History Museum of Basel.

The fossil preserves most of the postcranial skeleton in three dimensions, with many bones close to their original positions. The skull and neck are absent. A diffuse patch of organic material outlines part of the missing region, but it is too indistinct to supply a bony head or a detailed soft-tissue reconstruction.

Ultraviolet traces and their limits

The 2011 authors examined the slab with UVA lamps at wavelengths around 365–366 nanometres. Fluorescence made some fine skeletal details and the faint organic trace easier to see than under ordinary visible light. This method can reveal contrasts in a slab, but a bright patch is not automatically skin or a complete organ.

The paper also identifies greenish lines and spots as glue. That warning matters when an image appears to show delicate outlines near the head. The strongest conclusion is that the slab preserves a weak trace associated with the missing region; the precise tissue and its full anatomy remain uncertain.

From Aurorazhdarcho primordius to A. micronyx

The name Pterodactylus micronyx dates to Hermann von Meyer's work in 1856. Small Solnhofen pterosaurs were historically assigned to that name from a number of separate museum specimens. In 2013, Stephen C. Bennett compared the material with NMB Sh 110 and treated Aurorazhdarcho primordius as a younger synonym. He retained Aurorazhdarcho for the older species name, giving the combination A. micronyx.

That arrangement is widely followed, but the specimen set remains central to the question. Some later phylogenetic studies coded the NMB specimen and the older micronyx material separately to test relationships. Such a matrix is not, by itself, a formal decision to split the species again. Historical assignments to other genera, including Gnathosaurus and Aerodactylus, also show why a species list should be checked against the specimen actually discussed.

The 2011 paper initially placed the new form among azhdarchoid pterosaurs. Bennett later argued for a ctenochasmatid relationship. Subsequent analyses have not consistently reproduced one narrower position, in part because the missing skull and neck remove characters often useful in pterosaur classification. Its place within Pterodactyloidea is safer than a confident family label.

Age and Solnhofen setting

NMB Sh 110 came from the Solnhofen Lithographic Limestone of the Upper Eichstätt Formation, near Eichstätt in Bavaria. The authors assigned it to the early Tithonian, near 150 million years ago. The date describes the sedimentary interval, not the exact time when the animal died.

The Bavarian plattenkalks formed in a warm archipelago with shallow carbonate lagoons. Fine sediment and rapid burial helped preserve fragile skeletons, and some slabs retain traces of soft tissue. These rocks record more than one local setting and burial history; the lagoon scene on the cover is a broad reconstruction rather than the known position of the fossil.

Body size and pterosaur biology

The known animals were small compared with many later pterosaurs. Some specimens historically referred to micronyx have been interpreted as juveniles, so their dimensions cannot define the largest adult. NMB Sh 110 lacks the skull and neck and does not preserve a complete spread wing from which a direct wingspan can be measured.

The wing skeleton confirms a flying pterosaur, but it cannot establish exact flight speed, take-off behaviour or the distance an individual travelled. Solnhofen contains marine fish and other potential prey, yet the geological association does not prove that Aurorazhdarcho ate fish. Jaws, teeth, stomach contents or feeding traces would provide more direct dietary evidence.

Growth rates, sex, nesting and social behaviour are unknown. Differences among small skeletons could reflect age, species boundaries or historical misidentification. The available sample does not distinguish those alternatives cleanly.

What the fossils support

The strongest evidence is the nearly complete postcranial skeleton NMB Sh 110, its Bavarian origin and its early Tithonian age. Ultraviolet photography revealed faint contrasts, but did not recover a clear skull. The combination Aurorazhdarcho micronyx follows Bennett's 2013 synonymy, while the exact family placement and the boundaries of the referred material remain open to comparative testing.

Compare its changing name with the older Pterodactylus material, then browse other flying reptiles in the pterosaur catalogue. The familiar living-bird-like outline, colours and lagoon behaviour on the illustrations are reconstructions rather than observations from the slab.