GUIANA DOLPHIN (T) 



Sotaliaguianensis (P. -J. van Beneden 1864) 



Other Common Names 



None known. 



Description 



Guiana dolphins are the second smallest cetacean species 

 in the western North Atlantic, reaching a maximum length of 

 only about 5.6 feet (1.7 m). 



Their body shape is very similar to that of the Atlantic 

 bottlenosed dolphin, though the beak is less clearly 

 demarcated from the forehead. 



The rather prominent dorsal fin is nearly triangular, 

 curving only slightly backwards near the tip. 



Guiana dolphins are steel blue to dark brown on the back 

 and white on the belly. There is sometimes a brownish band 

 extending from the dark color of the back in front of the dorsal 

 fin back towards but not reaching the anus. 



Natural History Notes 



Guiana dolphins are usually found in groups of fewer than 

 10 individuals. 



May Be Confused With 



Because of their limited range and specialized habitats, 

 Guiana dolphins are unlikely to be confused with any other 

 cetacean species except perhaps Atlantic bottlenosed 

 dolphins (p. 128). These two species can be distinguished by 

 the following characteristics: 



Guiana Dolphins 



Atlantic Bottlenosed 

 Dolphins 



SIZE 



To only 5.6 feet (1.7 m). 8to as much as 12 feet (2.4 to 



3.7 m). 



DORSAL FIN 



More nearly triangular; cur- Broad- based, 

 ved only slightly backwards cate. 

 near tip. 



DISTRIBUTION 



tall, and fal- 



Found in rivers and estuar- 

 ies, extend into only very 

 shallow nearshore waters on 

 limited area of South Ameri- 

 can coast. 



Distribution 



Sometimes found nearshore 

 and in bays, river mouths, 

 and estuaries, but extend 

 farther offshore. 



Guiana dolphins are found in Lake Maracaibo, in the 

 rivers of Guyana, and in the nearshore coastal waters of the 

 northeastern portion of the Guianas. 



Stranded Specimens 



In their very limited range, stranded Guiana dolphins can 

 be readily identifed by their extremely small size (to 5.6 feet 

 11.7 m]) and nearly triangular dorsal fin. Furthermore, in 

 addition to the characteristics listed above distinguishing 

 living Guiana dolphins from Atlantic bottlenosed dolphins, 

 the species can be distinguished by differences in the 

 numbers of teeth: 



Atlantic Bottlenosed 

 Dolphins 



Guiana Dolphins 



TEETH 



20-26 in each upper jaw; 

 18-26 in each lower jaw. 



26-35 in each jaw; often 

 ragged in arrangement. 



Figure 147. — A Guiana dolphin from Kartabo, British Guiana. In the coastal portion 

 of its range along the northeastern South American coast, this species is most likely 

 to be confused with the Atlantic bottlenosed dolphin. Guiana dolphins are much 

 smaller, rarely exceeding 5.6 feet (1.7 m), have a more triangular dorsal fin, and 

 tend to be found more frequently in estuaries and rivers. [Photo by A. B. Van 

 Beneden from Zoologica VII H).by permitnon of the New York Zoological Society. ) 



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