Microtuban
Encyclopedia
Microtuban is an extinct genus
of azhdarchoid pterosaur
known from the Late Cretaceous of northern Lebanon
.
lacking the skull, holotype
SMNK PAL 6595. It was acquired from a local fosil dealer by the Staatliches Museum für Naturkunde Karlsruhe and was, as can be deduced from the qualities of the stone matrix, collected in the locality of Hjoûla in a marine layer of the Sannine Formation, dating to the early Cenomanian
stage of the Late Cretaceous
, about 99.6-96 million years ago. The fossil dealer however, indicated it came from a quarry at nearby Hâqel. Regardless, it is only the second pterosaur fossil found in Lebanon and a rare example of a pterosaur from the African continental plate, to which the area in Cretaceous times belonged. In this period the site was located hundreds of miles from the mainland coastline.
The specimen consists of the last cervical and first dorsal vertebrae, a shoulder girdle, the left wing and fragments of the hindlimbs. It represents an immature individual. Many bones are broken but the whole is still articulated. This was explained as being caused by a collision or a bite by a predator, just before or after death, after which the carcass quickly sank to the sea bottom.
and the type species
is Microtuban altivolans. The generic name is derived from Greek μικρός, mikros, "little", and Arab
التنين, tuban, "dragon" or basilisk
, also referring to Thuban
, the ancient Polar Star in the constellation Draco
. The specific name is derived from Latin
altus, "high", and volare, "to fly".
The authors indicated two unique derived traits, or autapomorphies: the second phalanx of the wing-finger is long, with 85% of the length of the first phalanx; the fourth phalanx is extremely reduced measuring but 1.1% of wing-finger length.
Possible juvenile traits included the lack of a notarium
, being a fusion of the front dorsal vertebrae, and a unfused scapula
and coracoid.
, using the comparative method. Of the four known azhdarchoid groups they excluded the Tapejaridae
and Azhdarchidae
, leaving the possibility that Microtuban was member of either the Thalassodromidae
or the Chaoyangopteridae
. As the two latter groups are mainly distinguished on the basis of traits in the skull, the very body part the Microtuban holotype lacks, it proved impossible to decide whether it were a thalassodromid or a chaoyangopterid. In either case it would have been the youngest known example of its group.
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 Cretaceous of northern Lebanon
Lebanon
Lebanon , officially the Republic of LebanonRepublic of Lebanon is the most common term used by Lebanese government agencies. The term Lebanese Republic, a literal translation of the official Arabic and French names that is not used in today's world. Arabic is the most common language spoken among...
.
Discovery
Microtuban is known only from a partially preserved skeletonSkeleton
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...
lacking the skull, 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...
SMNK PAL 6595. It was acquired from a local fosil dealer by the Staatliches Museum für Naturkunde Karlsruhe and was, as can be deduced from the qualities of the stone matrix, collected in the locality of Hjoûla in a marine layer of the Sannine Formation, dating to the early Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
stage of the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
, about 99.6-96 million years ago. The fossil dealer however, indicated it came from a quarry at nearby Hâqel. Regardless, it is only the second pterosaur fossil found in Lebanon and a rare example of a pterosaur from the African continental plate, to which the area in Cretaceous times belonged. In this period the site was located hundreds of miles from the mainland coastline.
The specimen consists of the last cervical and first dorsal vertebrae, a shoulder girdle, the left wing and fragments of the hindlimbs. It represents an immature individual. Many bones are broken but the whole is still articulated. This was explained as being caused by a collision or a bite by a predator, just before or after death, after which the carcass quickly sank to the sea bottom.
Naming and etymology
Microtuban was named by Ross A. Elgin and Eberhard Frey in 20112011 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:...
and 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...
is Microtuban altivolans. The generic name is derived from Greek μικρός, mikros, "little", and Arab
Arab
Arab people, also known as Arabs , are a panethnicity primarily living in the Arab world, which is located in Western Asia and North Africa. They are identified as such on one or more of genealogical, linguistic, or cultural grounds, with tribal affiliations, and intra-tribal relationships playing...
التنين, tuban, "dragon" or basilisk
Basilisk
In European bestiaries and legends, a basilisk is a legendary reptile reputed to be king of serpents and said to have the power to cause death with a single glance...
, also referring to Thuban
Thuban
Thuban also known by its Bayer designation Alpha Draconis is a star in the constellation of Draco. A relatively inconspicuous star in the night sky of the Northern Hemisphere, it is historically significant as having been the north pole star in ancient times...
, the ancient Polar Star in the constellation Draco
Draco (constellation)
Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar for many observers in the northern hemisphere...
. The specific 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...
altus, "high", and volare, "to fly".
Description
As the specimen is that of a not yet fully grown animal, it is difficult to estimate the adult size. The wingspan of the holotype can be deduced from the length of the wing elements. The upper arm, damaged in the fossil, measured about nine centimetres, the lower about seven. The fourth metacarpal is 122 millimetres long. The four phalanges of the, fourth, wing-finger measure 135, 114.5, 63.5 and 3.5 millimetres respectively.The authors indicated two unique derived traits, or autapomorphies: the second phalanx of the wing-finger is long, with 85% of the length of the first phalanx; the fourth phalanx is extremely reduced measuring but 1.1% of wing-finger length.
Possible juvenile traits included the lack of a notarium
Notarium
Notarium is a term used for the fused vertebra of the shoulder in birds and some pterosaurs. The structure helps brace the chest against the forces generated by the wings. In birds, the vertebrae are only in contact with adjacent vertebrae and ribs, while in some pterosaurs the notarium...
, being a fusion of the front dorsal vertebrae, and a unfused scapula
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
and coracoid.
Phylogeny
The describers assigned Microtuban 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...
, using the comparative method. Of the four known azhdarchoid groups they excluded the Tapejaridae
Tapejaridae
Tapejaridae are a family of pterodactyloid pterosaurs from the early Cretaceous period. Members are currently known from Brazil and China, where the most primitive genera are found, indicating that the family has an Asian origin....
and Azhdarchidae
Azhdarchidae
Azhdarchidae is a family of pterosaurs known primarily from the late Cretaceous Period, though an isolated vertebrae apparently from an azhdarchid is known from the early Cretaceous as well...
, leaving the possibility that Microtuban was member of either the Thalassodromidae
Thalassodromidae
Thalassodromidae is a family of pterodactyloid pterosaurs from the early Cretaceous period of Brazil. It contains two genera, Thalassodromeus and Tupuxuara.-Classification:The classification of thalassodromids is controversial...
or the Chaoyangopteridae
Chaoyangopteridae
The Chaoyangopteridae are a family of pterosaurs within the Azhdarchoidea.The clade Chaoyangopteridae was first defined in 2008 by Lü Junchang and David Unwin as: "Chaoyangopterus, Shenzhoupterus, their most recent common ancestor and all taxa more closely related to this clade than to Tapejara,...
. As the two latter groups are mainly distinguished on the basis of traits in the skull, the very body part the Microtuban holotype lacks, it proved impossible to decide whether it were a thalassodromid or a chaoyangopterid. In either case it would have been the youngest known example of its group.