Lipotidae

{{Short description|Family of river dolphins}}

{{Automatic taxobox

| name = Pacific river dolphins

| oldest_fossil = Miocene

| image = Lipotes vexillifer.png

| image_caption = Lipotes vexillifer

| image_alt = "Lipotes vexillifer"

| display_parents = 3

| taxon = Lipotidae

| authority = Zhou, Qian & Li, 1978

| subdivision_ranks = Genera

| subdivision = See text

}}

Lipotidae is a family of river dolphins containing the possibly extinct baiji of China and the fossil genus Parapontoporia from the Late Miocene and Pliocene of the Pacific coast of North America.Barnes, L.G., 1984. Fossil odontocetes (Mammalia: Cetacea) from the Almejas Formation, Isla Cedros, Mexico. PaleoBios 42:1-46L. G. Barnes. 1985. Fossil pontoporiid dolphins (Mammalia: Cetacea) from the Pacific Coast of North America. Contributions in Science 363:1-34. The genus Prolipotes, which is based on a mandible fragment from Neogene coastal deposits in Guangxi, China,K. Zhou, M. Zhou, and Z. Zhao. 1984. First discovery of a Tertiary platanistoid fossil from Asia. Scientific Reports of the Whales Research Institute 35:173-181. has been classified as an extinct relative of the baiji, but is dubious.N. D. Pyenson. 2009. Requiem for Lipotes: An evolutionary perspective on marine mammal extinction. Marine Mammal Evolution 25(3):714-724 The oldest known member of the family is Eolipotes from the Late Miocene of Japan.{{Cite journal|last1=Kimura |first1=T. |last2=Hasegawa |first2=Y. |title=New Fossil Lipotid (Cetacea, Delphinida) from the Upper Miocene of Japan |year=2024 |journal=Paleontological Research |volume=28 |issue=4 |pages=1–23 |doi=10.2517/PR220027 }}

The only species of the Lipotidae family that has flourished until recent times is the baiji (Lipotes vexillifer), which lives in the Yangtze River system, but its population has declined drastically since the second half of the 20th century due to the severe aggression of industrial and fishing activities in China, and is thought to have become extinct in the early 21st century.United States, National Marine Fisheries Service, Office of Protected Resources; Baiji/Chinese River Dolphin/Yangtze River dolphin (Lipotes vexillifer) 5-year review : summary and evaluation; 2017 https://repository.library.noaa.gov/view/noaa/16394

The putative kentriodontid "Lophocetus" pappus is a possible relative of Lipotidae.Olivier Lambert, Giovanni Bianucci, Mario Urbina, Jonathan H. Geisler; A new inioid (Cetacea, Odontoceti, Delphinida) from the Miocene of Peru and the origin of modern dolphin and porpoise families. Zool J Linn Soc 2017; 179 (4): 919-946. doi: 10.1111/zoj.12479. https://academic.oup.com/zoolinnean/article/179/4/919/3076080/A-new-inioid-Cetacea-Odontoceti-Delphinida-from?guestAccessKey=3b956b95-d215-488a-8d90-1cff59554290#63703008