Nothobranchius derhami, a new species of seasonal killifish from western Kenya
by Stefano Valdesalici and Giuseppe Amato – aqua 25 (3) – pp. 111-124
Nothobranchius derhami, new species, is described from seasonal habitats in the Nyando River system, belonging to the Lake Victoria basin, western Kenya. Nothobranchius derhami belongs to the N. ugandensis species group and is distinguished from all other members of the genus by the following characters in males: flank light blue with red scale margins; dorsal portion of the head red, lower jaw light blue; caudal fin plain red; pectoral fin hyaline; anal fin light blue proximally to creamy white distally, with series of red dots; dorsal fin almost red proximally with few white to light blue dots, subdistal white to light blue stripe; dorsal fin with black margin, anal fin with dark red to black margin, 15-17 dorsal and anal fin rays, 27-29 scales in the median lateral series, 10-12 transverse scale rows, and 14-16 circumpeduncular scales. In view of the very restricted distribution of N. derhami, it is suggested that its conservation status according to the IUCN Red List of Threatened Species guidelines would be Vulnerable (D2).