Franciscana - Pontoporia blainvillei

Taxonomy & Nomenclature

Scientific Name Pontoporia blainvillei
Author (Gervais and d'Orbigny, 1844)
Taxonomic Rank Species
Taxonomic # 180411
Common Names English: La Plata dolphin
English: Franciscana
Current Standing valid
Taxonomic Parents Kingdom: Animalia
  Phylum: Chordata
    Subphylum: Vertebrata
      Class: Mammalia
        Subclass: Theria
          Infraclass: Eutheria
            Order: Cetacea
              Suborder: Odontoceti
                Family: Iniidae
                  Genus: Pontoporia
Taxonomic Children
Synonyms (since 1950)
Taxonomic data is courtesy of the Integrated Taxonomic Information System (ITIS)
See ITIS metadata in XML

Physical Description / Field Identification

Although not a true freshwater dolphin, this primarily marine species is nonetheless related to them. The beak is extremely long and narrow, relatively the longest of any living species of cetacean. Although in calves, the beak is much shorter and stouter than it is older animals. The forehead is steep and rounded. The dorsal fin is low to moderately tall and triangular, with a rounded tip. The flippers are broad spatulate, sometimes with an undulating trailing edge. In many subadults, there are visible ridges along the surface, corresponding to the flipper bones. Morphological studies have documented the existence of two forms of franciscana, a smaller northern and a larger southern one. Males reach 1.63 m, and females 1.77 m in length. Maximum recorded weight is about 53 kg. Franciscana are countershaded brownish to dark gray above, and lighter brown (or even yellowish) to gray below and on the lower flanks. A faint dorsal cape is generally present. The long beak is lined with 50-62 fine pointed teeth per row, more than nearly any other species of cetacean.

Can be Confused With

Young franciscana may be confused with marine dolphins of the genus Sotalia, but can be identified by their very long beaks and more rounded dorsal fins, broad flippers, and small eyes. Bottlenose dolphins should be easy to distinguish, based on their much larger size and tall, falcate dorsal fins.

Distribution

Franciscana is found only along the east coast of South America, from Golfo San Matias, central Argentina, to Espirito Santo, central Brazil. They are primarily coastal, ranging no farther offshore than the 30 m isobatch. However, they may also be found in some estuaries, and they sporadically enter the la Plata River.

Ecology and Behavior

Franciscana resides in coastal habitat. However, there is very little known about the franciscana's natural history. This is due to two factors the difficulty of observing them in nature, and the paucity of research effort. They are found singly or in small groups of up to 15 individuals. In general, they appear to avoid vessels, and are not aerially active.

Peak calving for this species is in November and December. There has not been much research on the life history of this species, but sexual maturity may occur as early as 3 years. At birth, franciscana measure about 60-80 cm.

Feeding and Prey

Franciscana are opportunistic feeders and feed mostly near the bottom on several species of fish, cephalopods, and crustaceans.  Cooperative feeding has been observed in Argentina.

Threats and Status

Main threats include:

• Incidental mortality in gillnet fisheries (takes at least 1,500 animals per year)

• Habitat degradation

• Pollution

Total abundance of the species is not known, but the gillnet mortality alone is not thought to be sustainable. The current status of franciscana are “Data Deficient” (IUCN) and “Not Listed” (ESA).

Links

References

Bordino, P., G. Thompson, and M. Iniquez. 1999. Ecology and behaviour of the franciscana (Pontoporia blainvillei) in Bahia Anegada, Argentina. Journal of Cetacean Research and Management 1:213-222.

Brownell, Jr., R.L. 1989. Franciscana Pontoporia blainvillei (Gervais and d'Orbigny, 1844). pp. 45-68 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales. Academic Press.

Crespo, E.A. 2002. Franciscana Pontoporia blainvillei. pp. 482-485 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.

Crespo, E.A., G. Harris, and R. Gonzalez. 1998. Group size and distributional range of the franciscana, Pontoporia blainvillei. Marine Mammal Science 14:845-848.

Pinedo, M.C. 1991. Development and variation of the franciscana, Pontoporia blainvillei. Ph.D. dissertation, University of California, Santa Cruz.

Pinedo, M.C., R. Praderi, and R.L. Brownell, Jr. 1989. Review of the biology and status of the franciscana Pontoporia blainvillei. pp. 46-51 in W.F. Perrin, R.L. Brownell, Z. Kaiya and L. Jiankang, eds. Biology and conservation of the river dolphins. IUCN.

ITIS TSN180411
Status - ESA, U.S. FWS -
    -
Status - Red List, IUCN -
    VU (Global or one of the sub regions)
    VU (Rio Grande do Sul/Uruguay)
#records (spatial)57
#records (non-spatial)0
#datasets4
Year1987 - 2008
Latitude-42.58 - -18.42
Longitude-64.80 - -30.70
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