''Microtuban'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

azhdarchoid Azhdarchoidea (International Phonetic Alphabet, , meaning "azhdarchid-like forms") is a group of pterosaurs within the suborder Pterodactyloidea. Pterosaurs belonging to this group lived throughout the Early Cretaceous, Early and Late Cretaceous ...

pterosaur Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earli ...

known from the Late Cretaceous of northern

Lebanon Lebanon, officially the Republic of Lebanon, is a country in the Levant region of West Asia. Situated at the crossroads of the Mediterranean Basin and the Arabian Peninsula, it is bordered by Syria to the north and east, Israel to the south ...

Discovery

''Microtuban'' is known only from a partially preserved

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

lacking the skull,

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

SMNK PAL 6595. It was acquired from a local fossil 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 The Sannine Formation, also called the Sannine Limestone, is a Cretaceous geologic formation in Lebanon. It is a Konservat-Lagerstätte that contains a high diversity of well-preserved fish, reptiles, and invertebrates from the Tethys Ocean wit ...

, dating to the early

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

stage of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

, about 99.6–96

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

. The fossil dealer however, indicated it came from a quarry at nearby

Hâqel The Sannine Formation, also called the Sannine Limestone, is a Cretaceous geologic Formation (geology), formation in Lebanon. It is a Lagerstätte, Konservat-Lagerstätte that contains a high diversity of well-preserved fish, reptiles, and invert ...

. 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. ''Microtuban'' was named by Ross A. Elgin and Eberhard Frey in

2011 The year marked the start of a Arab Spring, series of protests and revolutions throughout the Arab world advocating for democracy, reform, and economic recovery, later leading to the depositions of world leaders in Tunisia, Egypt, and Yemen ...

and the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''Microtuban altivolans''. The generic name is derived from Greek μικρός, ''mikros'', "little", and

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

ثعبان, ''tuban'', "dragon" or

basilisk In European bestiary, bestiaries and legends, a basilisk ( or ) is a legendary reptile reputed to be a Serpent symbolism, serpent king, who causes death to those who look into its eyes. According to the ''Natural History (Pliny), Naturalis Histo ...

, also referring to

Thuban Thuban (), with Bayer designation Alpha Draconis or α Draconis, is a binary star system in the northern constellation of Draco. A relatively inconspicuous star in the night sky of the Northern Hemisphere, it is historically signifi ...

, the ancient Polar Star in the constellation Draco. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''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 In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones ( wrist bones), which articulate ...

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 In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...

: 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 or os dorsale is a bone consisting of 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 adjac ...

, being a fusion of the front dorsal vertebrae, and an unfused

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

and

coracoid A coracoid is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is present as part of the scapula, but this is n ...

Phylogeny

The describers assigned ''Microtuban'' to the

Azhdarchoidea Azhdarchoidea ( , meaning "azhdarchid-like forms") is a group of pterosaurs within the suborder Pterodactyloidea. Pterosaurs belonging to this group lived throughout the Early and Late Cretaceous periods, with one tentative member, '' Tendaguri ...

, using the comparative method. Of the four known azhdarchoid groups they excluded the

Tapejaridae Tapejaridae (from a Tupi language, Tupi word meaning 'the lord of the ways') is a Family (biology), family of azhdarchoid pterosaurs from the Cretaceous Period (geology), period. Members are currently known from Brazil, England, Hungary, Morocco, ...

and

Azhdarchidae Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cre ...

, leaving the possibility that ''Microtuban'' was member of either the

Thalassodromidae Thalassodromidae (meaning "sea runners") is a group of azhdarchoid pterosaurs from the Early Cretaceous (Albian) of Brazil. All known definitive members come from the Romualdo Formation of Brazil, which include the type genus '' Thalassodromeus' ...

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. A study upheld by paleontologist Nicholas Longrich and colleagues in 2018 had recovered ''Microtuban'' within the Chaoyangopteridae, in the

basalmost In phylogenetics, basal is the direction of the ''base'' (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to th ...

position. Their cladogram is shown below:

References

{{Portal bar, Paleontology, Lebanon Late Cretaceous pterosaurs of Asia ? Fossil taxa described in 2011

Discovery

Description

Phylogeny

See also

References