Sternarchogiton zuanoni de Santana & Vari, 2010

Family:  Apteronotidae (Ghost knifefishes), subfamily: Apteronotinae
Max. size:  17.8 cm TL (male/unsexed)
Environment:  demersal; freshwater
Distribution:  The single known sample of Sternarchogiton zuanoni originated in the rapids and waterfalls of Cachoeira de Kaituká in the Município de Altamira along the lower Rio Xingu in the eastern portions of the Amazon basin (Ref. 83662).
Diagnosis:  Sternarchogiton zuanoni is diagnosed from S. labiatus in the number of total anal-fin rays (129–153 versus 156–168, respectively), the interorbital width (28.8–39.4% of HL versus 19.5–24.6%, respectively), the body depth (13.3–17.3% of LEA versus 10.3–12.0%, respectively), the coloration of the anal fin (completely hyaline versus the presence of scattered brown speckling and a dark distal margin, respectively), the form of the lower lip (unelaborated versus the presence of a prominent tri-lobed structure, respectively), and the number of rows of conical teeth on the dentary (one versus two rows, respectively). Sternarchogiton zuanoni is distinguished from S. nattereri in the number of total anal-fin rays (129–153 versus 180–198, respectively), the interorbital width (28.8–39.4% of HL versus 19.9–27.6%, respectively), the length of the caudal appendage (22.4– 30.7% of LEA versus 14.6–20.4%, respectively), and the premaxillary dentition (teeth absent versus present in some sexually dimorphic males, respectively). Sternarchogiton zuanoni is diagnosable from S. porcinum in the number of total anal-fin rays (129–153 versus 182–216, respectively), the interorbital width (28.8–39.4% of HL versus 18.8–23.9%, respectively), the head width (46.2–57.3% of HL versus 39.1– 44.6%, respectively), the orbital diameter (9.3–14.1% of HL versus 4.5–7.7%, respectively), the coloration of the pectoral and anal fins (completely hyaline versus with black margins, respectively), and the dorsal profile of the head (distinctly convex versus straight or slightly convex, respectively). Sternarchogiton zuanoni is distinguished from S. preto in the number of total anal-fin rays (129–153 versus 189– 210, respectively), the interorbital width (28.8–39.4% of HL versus 17.8–25.9%, respectively), the orbital diameter (9.3– 14.1% of HL versus 2.9–8.3%, respectively), the coloration of the pectoral and anal fins (completely hyaline versus with black margins, respectively), and the premaxillary dentition (teeth absent versus present, respectively) (Ref. 83662).
Biology: 
IUCN Red List Status: Vulnerable (VU); Date assessed: 07 November 2018 (D2) Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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