Aedes (Stegomyia) annandalei (Theobald)

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 : 51-52

Aedes (Stegomyia) annandalei (Theobald)

subspecies annandalei ( Theobald, 1910 a) —original combination: Stegomyia annandalei . Distribution: Bangladesh, Cambodia, India, Indonesia, Myanmar, Nepal, Papua New Guinea, People’s Republic of China, Taiwan, Thailand, Vietnam ( Wilkerson et al. 2021).

subspecies quadricinctus ( Barraud, 1923b) —original combination: Stegomyia annandalei var. quadricincta (subspecific status by Harbach & Howard 2007). Distribution: India ( Barraud 1923b).

The taxonomic history of Ae. annandalei involves three nominal forms: Stegomyia annandalei Theobald, 1910 a, Aedes horishensis Yamada, 1921 and Stegomyia annandalei var. quadricincta Barraud, 1923b . Aedes horishensis , described from a single female collected at or near Horisha in present-day Taiwan, was recognized as a subspecies of annandalei by Lien (1962). Its taxonomic status thereafter is a matter of confusion. Mattingly (1965) listed it as a synonym of annandalei , but also indicated that he considered it to be a variety: “I agree with Lien that the evidence no longer warrants this being treated as a distinct species. However, the apparently low incidence of this type of marking [slight posterior shifting of pale bands on abdominal terga IV–VI] in Taiwan and its simultaneous occurrence in Indonesia, in both cases in areas where normal markings are the rule, seems to me to render his suggestion that it should be treated as a subspecies unacceptable. Since this character reappears in the Ae. scutellaris complex and is, therefore of particular interest, I consider that specimens showing it should be distinguished as var. horishensis Yamada. ” Likewise, Huang (1977) also made conflicting statements about the status of horishensis . In the abstract of her publication, she stated that “ Aedes horishensis Yamada is regarded as a variety of annandalei Theobald ”, whereas in her discussion of annandalei , she sided with Mattingly in noting that the posterior shifting of the abdominal bands is variable, and stated “Therefore, I consider horishensis Yamada to be a synonym of annandalei .” Despite these contradictions, horishensis was listed as a synonym of annandalei by Knight & Stone (1977), attributed to Mattingly (1965), Harbach (2018) and Wilkerson et al. (2021), attributed to both Mattingly (1965) and Huang (1977). Lu et al. (1997) agreed with the synonymy. Based on the findings and actions taken by Mattingly (1965), Huang (1977) and Lu et al. (1997), we agree that horishensis is probably conspecific with annandalei and should continue to be recognized as a synonymous nominal taxon.

Barraud (1923b) described Stegomyia annandalei var. quadricincta based on “One female from Nongpoh, Assam, July, 1922 (Barraud).” He noted there was “another female specimen from the same place which agrees with the above [description of quadricincta] in the markings of the hind tarsi, but the fore and mid legs have only two rings, as in the type form.” This is obviously an indication that the two forms were sympatric. Barraud (1934) more explicitly described the distinctive tarsal banding of quadricinctus as follows: “Differs from the type-form in having basal white markings to first four tarsal segments on all legs; markings at base of segments 3 and 4 on fore and mid-legs small and not forming complete rings; complete white rings on tarsal segments 1–4 on hind legs, that on 4 occupying nearly whole segment.”

Concomitant with the recognition of Stegomyia as a subgenus of Aedes by Edwards (1932a), the variety described by Barraud (1923b) became known as Aedes (Stegomyia) annandalei var. quadricinctus , and was subsequently listed as such in the catalogs of Stone et al. (1959) and Knight & Stone (1977). Mattingly (1965) and Huang (1977) both listed quadricinctus as a synonym of annandalei without explicit mention or discussion of its taxonomic status. Mattingly, however, noted that “Var. quadricinctus Barraud … has white rings on the first 4 tarsi [tarsomeres] of all legs. An otherwise similar ♀ from the type locality had only the first 2 segments [tarsomeres] banded on the fore and mid legs. I have not seen this type of variation in any Indomalayan material.” Perplexingly, Huang (1977) vaguely (doubtfully?) indicated that the tarsi of annandalei may sometimes exhibit the condition described for quadricinctus , i.e. that tarsomeres 1–4 of all legs have white bands. She described the tarsi of males as having the “fore- and midtarsi with basal white band on tarsomere 1, sometimes midtarsus with a few white scales on basal area of tarsomere 2 as well; hindtarsus with basal white bands on tarsomeres 1,2; tarsomere 3 dark [emphasis ours]; tarsomere 4 with basal 0.67 white band to all dark…”. She noted females are essentially the same except that “Foretarsomere 2 sometimes with a few white scales on basal area; midtarsomere 2 with basal white band; hindtarsomere 4 with basal 0.83 white band; sometimes hindtarsomere 3 [emphasis ours] with a few white scales on basal area as well…”.

The tacit synonymy of quadricinctus with annandalei published by Huang (1977) was not published in the world catalog of the Culicidae of Knight & Stone (1977) because the cut-off date for additions to the catalog was the end of 1973, but neither was it recorded in the three subsequent catalog supplements ( Knight 1978; Ward 1984, Ward 1992). Unaware of the synonymy by Huang (1977), Harbach & Howard (2007) followed Knight & Stone in recognizing quadricinctus as a variety, which they deemed to be subspecific under provisions of Article 45.6.4 of the International Code of Zoological Nomenclature. Despite knowing that the leg markings of annandalei are subject to variation ( Barraud 1923b; Mattingly 1965; Huang 1977) and recognizing that “Although it is likely that the name quadricincta applies to an infrasubspecific form…”, Harbach & Howard were obligated to reveal that quadricinctus “officially has subspecific rank” under provisions of the Code. In view of the earlier synonymy by Huang (1977), the change of rank from variety to subspecies was unnecessary and unsupportable.

A number of different DNA sequences are available in GenBank for specimens of Ae. annandalei from China and Singapore, but until molecular data become available for specimens of quadricinctus from its type locality in India, we must agree with Mattingly (1965) and Huang (1977) that quadricinctus is merely a morphological variant and synonym of Ae. annandalei . To avoid any doubt, quadricincta is hereby formally regarded as a synonymous name: quadricincta Barraud, 1923b, junior subjective synonym of Aedes (Stegomyia) annandalei ( Theobald, 1910 a) . Consequently, “ Aedes quadricinctus ” should be removed from the list of species of Aedes included in the Encyclopedia of Life.