''Bawitius'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of giant polypterid from the

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...

(lower

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 s ...

)

Bahariya Formation The Bahariya Formation (also transcribed as Baharija Formation) is a fossiliferous geologic formation dating back to the early Cenomanian, which outcrops within the Bahariya depression in Egypt, and is known from oil exploration drilling across ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

. The

type species In 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 species that contains the biological type specimen ...

is ''B. bartheli'', named as a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of ''

Polypterus ''Polypterus'' is a genus of freshwater fish in the bichir family (Polypteridae) of order Polypteriformes. The type species is the Nile bichir (''P. bichir''). Fish in this genus live in various areas in Africa. ''Polypterus'' is the only kno ...

'' in 1984, and the genus

etymology Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...

comes from

Bawiti El-Bawiti (Arabic: الباويطي, ''al-Bāwīṭī, from'' ) is a town in the Western desert in Egypt. With 30,000 inhabitants, it is the largest settlement in the Bahariya Oasis. The tombs of ''Qarat Qasr Salim'' hill On a low ridge overl ...

, the principal settlement of the

Bahariya Oasis El-Wahat el-Bahariya or el-Bahariya ( ar, الواحات البحرية "''El-Wāḥāt El-Baḥrīya''", "the Northern Oases"); is a Depression (geology), depression and a naturally rich oasis in the Western Desert (Egypt), Western Desert of Egypt ...

in Egypt. It is known from the holotype TU-B SFB 69 Vb 003 (= Bah 5/12-016): left ectopterygoid scales and some sparse

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...

Morphology

Compared to modern polypterids, ''Bawitius'' was enormous: the ''Bawitius'' holotype ectopterygoid is five times larger than the one of ''

'' and the scales are unusually large, too: these remains suggest the living animal may have been up to 300 centimeters (9.8 feet) in length. The morphology of ''Bawitius'' is different enough to justify its assignment to a new genus apart from ''Polypterus''. Unique features of the genus are, for example, an anterioposteriorly elongated contact between the lateral process and the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

, a high, narrow ectopterygoid and the presence of 14 teeth in the main tooth row. The scales are different, too, apart from size, from those of modern polypterids: they feature a discontinuous

ganoine Ganoine or ''ganoin'' is a glassy, often multi-layered mineralized tissue that covers the scales, cranial bones and fin rays in some non-teleost ray-finned fishes, such as gars, bichirs, and coelacanths. It is composed of rod-like, pseudoprism ...

layer, a rectilinear shape, and small articular processes.

Ecological relevance

The existence of drastically different polypterids such as ''Bawitius'' and '' Serenoichthys'' corroborates the existence of a variety of polypterid fishes in the ecosystems of Late Cretaceous of North Africa and Brazil.

References

{{Taxonbar, from=Q4873780 Polypteridae Prehistoric ray-finned fish genera Cretaceous bony fish Prehistoric fish of Africa Bahariya Formation Fossil taxa described in 2012