Generi Najae a viginti ad viginti duae species descriptae olim erant, sed genus nuper identidem emendatum est, ut fontes academici magnopere variant.[4] Emendatio autem anni 2009, latissime accepta,[5] docet genera Boulengerinam et Paranajam eadem ac Naja esse. Secundum illam emendationem, generi Najae nunc sunt 38 species.[6]
Species Najaelongitudine variant, et corpora plurimarum sunt tenuia. Plurimae usque ad 1.84 metra longae crescunt; longitudines autem maximae sunt 3.1 fere metra, Naja melanoleuca fortasse longissima.[7] Omnes species anteriorem corporis quartam supra solum tollere, collumque complanare ad maiores videndas possunt.
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123Minton, SA(1974).Venom diseases.Springfield Illinoesiae:Thomas Publisher, Limited, Charles C..ISBN978-0-398-03051-3.
↑Tan, N.H., Choy, S.K., Chin, K.M., et Gnanajothy, P.(1994)."Cross-reactivity of monovalent and polyvalent Trimeresurus antivenoms with venoms from various species of Trimeresurus (lance-headed pit viper) snake".Toxicon32(7): 849–853.
Broadley, Donald G. 1974. A review of the cobras of the Naja nigricollis complex in southwestern Africa (Serpentes, Elapidae). Windhoek, S.W. Africae: Staatsmuseum.
Laurenti, Iosephus Nicolaus. 1768. Specimen medicum, exhibens synopsin reptilium emendatam cum experimentis circa venena et antidota reptilium austriacorum. Vindobonae: Joan Thomae. Editio interretialis.
Van Wallach, Wolfgang Wüster, et Donald Broadley. 2009. "In praise of subgenera: taxonomic status of cobras of the genus Naja Laurenti (Serpentes: Elapidae)." Zootaxa 2236 (1): 26–36. PDF.