Atlantirivulus guanabarensis Costa, 2014

Family:  Rivulidae (Rivulines), subfamily: Rivulinae
Max. size:  3.53 cm SL (male/unsexed); 3.14 cm SL (female)
Environment:  benthopelagic; freshwater
Distribution:  South America: river drainages flowing into the Guanabara bay, and adjacent coastal plains to west, including the Jacarepaguá lagoon system in Rio de Janeiro, Brazil.
Diagnosis:  Dorsal soft rays (total): 7-9; Anal soft rays: 14-16; Vertebrae: 33-34. Atlantirivulus guanabarensis can be diagnosed from all species of the genus Atlantirivulus by the following combination of characters: lateral line divided into two sections (vs. single); lateral line with one neuromast by scale (vs. lateral line often interrupted by scales without neuromasts); 22 - 26 neuromasts in the section of infraorbital series around orbit (vs. usually 17 - 22, sometimes 23 or 24); distal margin of the anal fin and ventral margin of the caudal fin with a narrow, well-defined dark reddish grey stripe in males (vs. never a similar color pattern), melanophore patch on the postorbital region extending ventrally to the pre-opercular series of neuromasts (vs. not reaching pre-opercular series of neuromasts); snout blunt (vs. slightly pointed); ventral portion of head and venter white (vs. orangish yellow); flank without triangular light blue spots in males (vs. present); and base of the dorsal and anal fins without grey reticulum in males (vs. present) (Ref. 102354). Description: caudal fin oval; longitudinal series of scales 33- 34; transverse series of scales 7-8 (Ref. 102354).
Biology: 
IUCN Red List Status: Least Concern (LC); Date assessed: 07 November 2018 Ref. (130435)
Threat to humans:  harmless


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