Culex nocturnus, Theobald, 1903

Harbach, Ralph E. & Wilkerson, Richard C., 2023, The insupportable validity of mosquito subspecies (Diptera: Culicidae) and their exclusion from culicid classification, Zootaxa 5303 (1), pp. 1-184 : 19-20

Subspecies nocturnus

Descriptions of subspecies nocturnus are very similar to descriptions of vexans , which has led to many different opinions concerning its status. It was described by Theobald (1903a) from “several ♀ ’s” from “Ba in Fiji ”. Townsend (1990) found two syntype females in the collection of the Natural History Museum, London. Theobald (1903a) described the species as having the “Thorax deep brown, covered densely with narrow-curved, bright brown and golden scales, scarcely showing any definite ornamentation; proboscis with a minute black tip and base, remainder ochraceous.” The legs are as in the description of vexans above. “Abdomen deep brown with basal white bands curved in the middle…. ♀. Head brown, with narrow curved pale golden scales on the crown, with black upright forked scales, flat black scales at the sides with a median white patch…. Abdomen …sixth and seventh segments with narrow apical yellow bands, no basal pale band or mark to the last; laterally are median white spots…. Legs …tibiae deep brown, paler ventrally…. Observations.... The abdominal ornamentation is very characteristic; the species cannot well be mistaken for any other. The proboscis is really very broadly pale banded.” Theobald included descriptions of all life stages except the egg, none of which provided distinguishing characters.

The following publications concerning the nominal taxon nocturnus are arranged by taxonomic status. A few authors gave expanded rationale for their judgements ( Bohart & Ingram 1946b; Belkin 1962; Reinert 1973; Lee et al. 1982), which were summarized by Lee et al. (1982), as shown below. This is not intended to be an exhaustive listing (* = with some sort of illustration).

As a synonym of vexans . Dyar (1920, 1921a); Senior-White (1923); Freeborn (1926); Edwards (1924); Edwards (1932a); Natvig (1948); Senevet & Andarelli (1954) [who followed Edwards 1932a]; Carpenter & LaCasse (1955) [subspecies arabiensis ? and nipponii also listed as synonyms of vexans ]; Reinert (1973); Knight & Stone (1977) [who we assume followed Reinert 1973]; Reinert et al. (2004).

As a synonym of Aedes (Ochlerotatus) vigilax ( Skuse, 1889) . Cooling (1924).

As a subspecies of vexans . * Bohart & Ingram (1946b); * Yamaguti & LaCasse (1950); Knight & Hull (1951); * Knight & Hull (1953); Laird (1955); Bohart (1957); Stone et al. (1959); Iyengar (1960); Stone (1961b); Lien (1962); * Joyce & Nakagawa (1963); * Holway & Bridges (1970); Basio (1971); * Baisas (1974); Tanaka et al. (1979); Harbach (2018); Wilkerson et al. (2021).

As species nocturnus . * Theobald (1903a); Edwards (1912a), in genus Ochlerotatus but “Doubtfully distinct from the preceding [ vigilax Skuse, 1889 ]”; * Penn (1949), as vexans but possibly represents subspecies nocturnus ; * Belkin (1962); Peters & Christian (1963), included as both a species and apparently inadvertently as a subspecies of vexans ; Stone (1963); Belkin (1965); Stephan (1966); Standfast (1967); Maffi (1977).

Lee et al. (1982), as species nocturnus , stated the following in a footnote.

Although F.W. Edwards (1924) synonymised nocturnus with vexans it was later considered a variety or subspecies of vexans by regional authors, commencing with Bohart & Ingram (1946).

Belkin (1962) provisionally raised nocturnus to specific rank, mainly on the basis of branching of larval head hairs [setae]. He recognised that the taxonomic status of nocturnus was uncertain, clarification awaiting study of the vexans complex.

Reinert (1973) sank nocturnus as a synonym of vexans vexans “in the absence of sufficient biological, behavioural and genetical data on the Pacific Island populations of vexans , and since specimens of these populations fall within the variable range of the morphological characters of other populations within the distribution of the species”.

For the time being we have chosen to retain nocturnus as a species partly because the synonymising of nocturnus under vexans gives vexans an extraordinarily wide distribution far greater than that achieved by any other non-domestic species.

We agree with the summary and conclusions of Lee et al. (1982) and thus hereby return nocturnus to its original species status: Aedes (Aedimorphus) nocturnus ( Theobald, 1903a) . Synonyms: Culicada eruthrosops Theobald, 1910 ; Culex nocturnus var. niger Theobald, 1913b . Aedes nocturnus is currently listed as a species in the Encyclopedia of Life.