''Pontogeneus'' (''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'') is a genus of extinct

cetacea Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

n known from fossils recovered from Late Eocene sediments (Bartonian-Priabonian stages) of the southeastern United States (most notably Alabama and Florida).

Classification

When ''"Zeuglodon" brachyspondylus'' was formerly included, ''Pontogeneus'' was depicted as having a skeleton similar to that of '' Basilosaurus cetoides'', although the posterior thoracic vertebrae, the lumbar vertebrae, and the anterior caudal vertebrae had proportions closer to those seen in members of the archaeocete

Subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Dorudontinae.

Taxonomic history

In 1852, Joseph Leidy had erected ''Pontogeneus priscus'' based on the centrum of a single cervical vertebra in the collections of the Academy of Natural Sciences in Philadelphia. Leidy noted that the centrum had been collected from exposures along the Washita River in Louisiana. synonymized these two taxa to form ''Pontogeneus brachyspondylus'' which he listed as '' incertae sedis''. designated ''Pontogeneus priscus'' and ''Zeuglodon brachyspondylus'' to be ''nomina dubia'' based on the lack of diagnostic characters that distinguish the type specimens from other basilosaurids. While ''Pontogeneus priscus'' is no longer considered valid, "Z." brachyspondylus appears similar to '' Masracetus'' from Egypt (which was also referred to ''Z. brachyspondylus'' in the past) and may represent either a species of ''Masracetus'' or a distinct and closely related but as-yet-unnamed genus.Gingerich, Philip D (2007). "Stromerius nidensis, new archaeocete (Mammalia, Cetacea) from the Upper Eocene Qasr El-Sagha Formation, Fayum, Egypt". Contributions from the Museum of Paleontology 31 (13): 363–78. OCLC 214233870.

Formerly assigned to ''Pontogeneus''

''"Zeuglodon brachyspondylus"'' () was erected for several vertebrae collected in either Choctaw or Washington counties in southern Alabama. Basilosaurid remains from Egypt were tentatively assigned to ''Zeuglodon brachyspondylus'' based on superficial similarities to the syntype series (under the old hypothesis of synonymy of ''Pontogeneus'' and ''Zeuglodon brachyspondylus''). Stromer, Ernst, 1908. Die Archaeoceti des ägyptischen Eozäns. Beiträge zur Paläontologie und Geologie Österreich-Ungarns und des Orients, Vienna, 21: 106-178. However, these remains were given their own genus, ''Masracetus'', given minor differences from "Z." ''brachyspondylus''.

Notes

References

* * * * * * {{Taxonbar, from=Q9061700 Basilosauridae Eocene cetaceans Archaeoceti Eocene mammals of North America Prehistoric cetacean genera Nomina dubia