Noctuoidea is the superfamily of noctuid (Latin "night owl") or "owlet" moths, and has more than 70000 described species, the largest number of for any Lepidopteran superfamily. Its classification has not yet reached a satisfactory or stable state. Since the end of the 20th century, increasing availability of molecular phylogenetic data for this hugely successful radiation has led to several competing proposals for a taxonomic arrangement that correctly represents the relationships between the major lineages.
Briefly, the disputes center on the fact that in old treatments (which were just as unable to reach a general consensus) the distinctness of some groups, such as the Arctiidae or Lymantriidae, was overrated due to their characteristic appearance, while some less-studied lineages conventionally held to be Noctuidae are in fact quite distinct. This requires a rearrangement at least of the latter family (by simply including anything disputed within it). This is quite unwieldy, and various more refined treatments have been proposed in response to it. While there is general agreement on what the basal families of Noctuoidea are, the more diverse advanced group may be treated as one all-encompassing Noctuidae, two huge and two smaller, or even (if Arctiidae or Lymantriida are kept distinct) more than four families, which are in some cases still quite sizeable.
Recent developments
There are several recent studies suggesting a radical change in the traditional family level classification. Recent works in redifining the families within the Noctuoidea has been carried out by Kitching (1984), Poole (1995), Kitching and Rawlins [1998], Speidel et al. (1996), Mitchell et al. (1997, 2000, 2006), Fibiger and Lafontaine (2005), Lafontaine and Fibiger (2006) and Zahiri et al. (2010).
The Noctuoidea can be divided into two broad groups, those with a trifid forewing venation (Oenosandridae, Notodontidae and Doidae), and those with a quadrifid forewing venation (e.g., Arctiidae, Lymantriidae, Nolidae, Noctuidae). What has emerged from these investigations is that the quadrifid Noctuoidea form a monophyletic group. In 2005, Fibiger and Lafontaine arranged the quadrifid (forewing) group into several families, including the quadrifine (hindwing) Erebidae and trifine (hindwing) Noctuidae, based on evidence that suggested that the trifine noctuid subfamilies were derived from within the quadrifine subfamilies, so the family Erebidae would not be strictly monophyletic.
Lafontaine and Fibiger in 2006 then redefined the Noctuidae to include the entire quadrifid group, believing the Arctiidae, Lymantriidae, and Nolidae to be derived from within this expanded concept of Noctuidae (and closely related to the subfamily Catocalinae). In essence, groups such as the Arctiidae, which had previously been treated as a separate family, were more closely related to groups within the Noctuidae than to non-noctuid families. In order to address this, a revised classification would have meant either recognizing over 20 (often weakly defined) families, or a single well-defined family with numerous subfamilies. The latter was adopted (Lafontaine and Fibiger 2006).
More recent evidence from nuclear genes (Zahiri et al. 2010) confirms that the quadrifid (forewing) noctuoids form a monophyletic group, but also that this group can be further arranged into four monophyletic subgroups: 1) the quadrifine subfamilies; 2) the trifine subfamilies; 3) the Nolinae; and 4) the Euteliinae. Considering the massive size of the family, and the large number of subfamilies, tribes, and subtribes to arrange into a classification, Zahiri et al. (2010) chose the option of recognizing these four groups as families, namely Erebidae, Noctuidae, Nolidae, and Euteliidae, in addition to the basal trifid families.
Systematics
This follows Lafontaine & Fibiger (2006), with the additions of Thiacidinae Hacker & Zilli, 2007 and taxa in Micronoctuidae Fibiger, 2005. Note that the placement of Arctiidae, Lymantriidae and Nolidae as subfamilies of Noctuidae has been largely rejected by subsequent authors. An updated classification for North American Noctuoidea has recently been published (Lafontaine & Schmidt, 2010) and further changes are imminent for a global molecular review of the superfamily (Zahiri et al., in press).