Aurorazhdarcho
Encyclopedia
Aurorazhdarcho is an extinct genus
of azhdarchoid pterosaur
known from the Late Jurassic
of Bavaria
, southern Germany
.
, in layers of the Solnhofen limestone
. The fossil was prepared by Gerd Stübener and acquired by the Swiss Naturhistorisches Museum Basel. Based on the specimen, the type species
Aurorazhdarcho primordius was named and described by Eberhard Frey, Christian A. Meyer and Helmut Tischlinger in 2011
. The generic name is derived from Latin
aurora, "dawn" and Kazakh
Azhdarcho, the name of a mythical dragon. The specific name means "primordial" or "the very first" in Latin.
The holotype
of Aurorazhdarcho, NMB Sh 110, was found in the Upper Eichstätt Formation dating to the early Tithonian
stage of the Late Jurassic
, 150 million years ago. It consists of a nearly complete skeleton
, three-dimensionally preserved on a single slab with the counterplate having been removed, lacking the skull and neck. However, the head and neck are present as impressions, movement of these elements on the bottom of the lagoon the carcass descended on leaving a natural mould covered by organic remains in the form of calcium phosphate
flakes made visible by the UV-photography of Tischlinger. That the head and neck are now absent is explained by the animal being killed by a partially failed attack by a predator, almost ripping off these parts, after which the body quickly sank. Subsequent bloating would then have caused the head to drift away. The individual was probably subadult and, as indicated by the fusion of the ischiopubes in the pelvis, a male as it lacks a wide birth canal.
The shoulder girdle was by the describers reconstructed with a low shoulder joint. The legs were relatively long with the shinbone over a third longer than the thighbone. In the wing the metacarpals were very elongated, the fourth metacarpal being longer than the lower arm. The first to fourth phalanges of the wing finger have the respective length of 119, 70.8, 50.8 and 50.6 millimetres.
and placed in a new family, the Protazhdarchidae, of which it is the only named member. It would then be the oldest known azhdarchoid with the dubious exception of the "Doratorhynchus
" material.
The describers rejected the use of a cladistic analysis to establish the phylogeny. Using the comparative method they found that Aurorazhdarcho was closest in proportions to the ctenochasmatid
Ctenochasma
elegans, a species also known from the Solnhofen, but they concluded that Aurorazhdarcho belonged to the Azhdarchoidea because it shared certain evolutionary key adaptations with that group, the most decisive of which they considered to be the low shoulder joint. The position of the shoulder joint with Ctenochasma could not be established but the describers assumed it was higher because of the closer relation of that taxon with Pterodactylus
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of azhdarchoid pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
known from the Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
of Bavaria
Bavaria
Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...
, southern Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
.
Discovery and naming
In 1999 amateur paleontologist Peter Katschmekat uncovered a fossil of a pterosaur in the Blumenberg Quarry, three kilometres northwest of EichstättEichstätt
Eichstätt is a town in the federal state of Bavaria, Germany, and capital of the District of Eichstätt. It is located along the Altmühl River, at , and had a population of 13,078 in 2002. It is home to the Katholische Universität Eichstätt-Ingolstadt, the lone Catholic university in Germany. The...
, in layers of the Solnhofen limestone
Solnhofen limestone
The Solnhofen Plattenkalk is a Jurassic Konservat-Lagerstätte that preserves a rare assemblage of fossilized organisms, including highly detailed imprints of soft bodied organisms such as sea jellies...
. The fossil was prepared by Gerd Stübener and acquired by the Swiss Naturhistorisches Museum Basel. Based on the specimen, the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
Aurorazhdarcho primordius was named and described by Eberhard Frey, Christian A. Meyer and Helmut Tischlinger in 2011
2011 in paleontology
-Lobopods:-Arachnids:-Insects:-Newly named jawless vertebrates:-Newly named acanthodian:-Newly named cartilaginous fishes:-Newly named bony fishes:-Newly named lepospondyls:-Newly named temnospondyls:-Newly named lissamphibians:...
. The generic name is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
aurora, "dawn" and Kazakh
Kazakh
Kazakh may refer to:*Kazakhstan*Kazakhs, an ethnic group*Kazakh language*Kazakh cuisine*Qazakh Rayon, Azerbaijan*Qazax, Azerbaijan*Kazakh Uyezd, administrative district of Elisabethpol Governorate during Russian rule in Azerbaijan...
Azhdarcho, the name of a mythical dragon. The specific name means "primordial" or "the very first" in Latin.
The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
of Aurorazhdarcho, NMB Sh 110, was found in the Upper Eichstätt Formation dating to the early Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
stage of the Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
, 150 million years ago. It consists of a nearly complete skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, three-dimensionally preserved on a single slab with the counterplate having been removed, lacking the skull and neck. However, the head and neck are present as impressions, movement of these elements on the bottom of the lagoon the carcass descended on leaving a natural mould covered by organic remains in the form of calcium phosphate
Calcium phosphate
Calcium phosphate is the name given to a family of minerals containing calcium ions together with orthophosphates , metaphosphates or pyrophosphates and occasionally hydrogen or hydroxide ions ....
flakes made visible by the UV-photography of Tischlinger. That the head and neck are now absent is explained by the animal being killed by a partially failed attack by a predator, almost ripping off these parts, after which the body quickly sank. Subsequent bloating would then have caused the head to drift away. The individual was probably subadult and, as indicated by the fusion of the ischiopubes in the pelvis, a male as it lacks a wide birth canal.
Description
Aurorazhdarcho was a relatively small pterosaur. The combined elements of a single wing of the type specimen have the extended length of 537.8 millimetres. The impressions indicate the head was elongated with the eye socket in a high position. The snout might have carried a high, rounded, crest. The impression of the neck is relatively short and shows signs of a throat pouch.The shoulder girdle was by the describers reconstructed with a low shoulder joint. The legs were relatively long with the shinbone over a third longer than the thighbone. In the wing the metacarpals were very elongated, the fourth metacarpal being longer than the lower arm. The first to fourth phalanges of the wing finger have the respective length of 119, 70.8, 50.8 and 50.6 millimetres.
Phylogeny
Aurorazhdarcho was by the describers assigned to the AzhdarchoideaAzhdarchoidea
Azhdarchoidea is a group of pterosaurs within the suborder Pterodactyloidea.-Classification:Listing of families and genera after Unwin 2006 except where specified.* Superfamily Azhdarchoidea** Genus "Aurorazhdarcho"** Family Chaoyangopteridae...
and placed in a new family, the Protazhdarchidae, of which it is the only named member. It would then be the oldest known azhdarchoid with the dubious exception of the "Doratorhynchus
Doratorhynchus
Doratorhynchus is a generic replacement name for Pterodactylus validus, in 1875 suggested by Harry Govier Seeley. Today it is considered a nomen vanum....
" material.
The describers rejected the use of a cladistic analysis to establish the phylogeny. Using the comparative method they found that Aurorazhdarcho was closest in proportions to the ctenochasmatid
Ctenochasmatidae
Ctenochasmatidae is a group of pterosaurs within the suborder Pterodactyloidea.-Classification:Listing of subfamilies and genera after Unwin 2006 unless otherwise noted.* Family Ctenochasmatidae** Elanodactylus** Gegepterus...
Ctenochasma
Ctenochasma
Ctenochasma is a genus of Late Jurassic pterosaur belonging to the suborder pterodactyloidea. Three species are currently recognized: C. roemeri , C. taqueti, and C. elegans...
elegans, a species also known from the Solnhofen, but they concluded that Aurorazhdarcho belonged to the Azhdarchoidea because it shared certain evolutionary key adaptations with that group, the most decisive of which they considered to be the low shoulder joint. The position of the shoulder joint with Ctenochasma could not be established but the describers assumed it was higher because of the closer relation of that taxon with Pterodactylus
Pterodactylus
Pterodactylus is a genus of pterosaurs, whose members are popularly known as pterodactyls. It was the first to be named and identified as a flying reptile...
.