Anopheles (Anopheles) gigas Giles

Anopheles (Anopheles) gigas Giles

subspecies crockeri Colless, 1955 —original combination: Anopheles gigas ssp. crockeri. Distribution: Sabah, Malaysia [Saung-Saung, Sunsuran Trace, North Borneo] (Colless 1955).

subspecies danaubento Mochtar & Walandouw, 1934 —original combination: Anopheles gigas var. danaubento. Distribution: Sumatra (Mochtar & Walandouw 1934).

subspecies formosus Ludlow, 1909a —original combination: Anopheles formosus. Distribution: Indonesia, Philippines (Wilkerson et al. 2021).

subspecies gigas Giles, 1901b —original combination: Anopheles gigas. Distribution: India (records from other countries listed in Wilkerson et al. 2021 either apply to the other subspecies, are doubtful or require verification).

subspecies oedjalikalah Nainggolan, 1939 —original combination: Anopheles gigas var. oedjalikalah [as Oedjali Kalah]. Distribution: Sumatra (Nainggolan 1939).

subspecies pantjarbatu Waktoedi Koesoemawinangoen, 1954 —original combination: Anopheles gigas var. pantjarbatu. Distribution: Sumatra (Waktoedi Koesoemawinangoen 1954).

subspecies refutans Alcock, 1913 —original combination: Anopheles gigas var. refutans. Distribution: Sri Lanka (Alcock 1913).

The nominotypical subspecies, from India, is a member of the Gigas Complex, Gigas Subgroup of the Lindesayi Group. A coordinate grouping, the Baileyi Complex (Somboon et al. 2020b; Namgay et al. 2020), is also included in the Gigas Subgroup. Knight & Stone (1977) treated all of what is now the Baileyi Complex (An. baileyi Edwards, 1929b; An. simlensis James, 1911) (in James & Liston 1911) plus the Gigas Complex (the above plus An. sumatranus Swellengrebel & Rodenwaldt, 1932) as varieties of the nominotypical subspecies. Another species of the Gigas Complex, An. prachongae Rattanarithikul & Harrison, 2017 (in Harbach et al. 2017), was described subsequently. Species of the Gigas Complex are large mosquitoes found at higher elevations (≥ 1,000 m) in mountainous areas of the Oriental, Palearctic and Australasian Regions. It is generally accepted that changes in climate can isolate populations on mountain refugia, which then lead to fragmented distributions of related species (reviewed by Harbach et al. 2017), as appears to be the pattern here.

The nominotypical subspecies occurs in southwestern India (type locality: Conoor (2,000 m), Nilgiri Hills, Madras, India). None of the other subspecies has been found in India. Subspecies crockeri is the only member of the complex found in Borneo (type locality: Saung-Saung, Sunsuran [Sunsuron?] Trace, northern Borneo). Characters to separate it from the other subspecies have been discussed and illustrated by Colless (1955), Reid (1968) and Harbach et al. (2017). The last authors also questioned its subspecific status. It is characterized as follows. Female: Maxillary palpus dark at apex; costa of wing without preapical pale spot (only present on costa in An. simlensis), fringe spots present at apices of veins R 4+5 and M 3+4 and between veins CuA and 1A, fringe spot absent between apices of M 3+4 and CuA (only present in An. sumatranus). Larva: Seta 2-C long, longer than 0.5 length of head; 3-C long, about 0.67 length of 2-C, with 2,3 basal branches; 4-C stout, single or branched at apex. Given the allopatric distribution in comparison to the other subspecies, and its distinctive morphological characters, it is likely that crockeri is genetically distinct and should therefore be afforded specific status: Anopheles (Anopheles) crockeri Colless, 1955 . Anopheles crockeri is currently listed as a species in the Encyclopedia of Life.

Subspecies formosus is the only member of the complex described from the Philippines (type locality: Camp John Hay, Benguet, Philippines). Characters separating it from other subspecies of the complex are listed in Harbach et al. (2017). King (1931) described and illustrated distinguishing characters, a few of which are given here, as follow. Female: Maxillary palpus pale apically; wing without fringe spots except for one between the tips of veins CuA and 1A; preapical pale spot present on costa and veins R 1 and R 2. Larva: Seta 2-C usually single; 3-C 0.5 or more length of 2-C, with 2–6 branches; 4-C nearly as long as 3-C, with 3–8 basal branches. Given the allopatric distribution in comparison to the other subspecies, and its distinctive morphological characters, it is likely that formosus is genetically distinct and should therefore be afforded specific status: Anopheles (Anopheles) formosus Ludlow, 1909a . Anopheles formosus is currently listed as a species in the Encyclopedia of Life.

Subspecies refutans is the only member of the complex described from Sri Lanka. The maxillary palpus of the female has three or four narrow white bands, one usually terminal (Alcock 1913). The wing fringe is all dark except for a pale spot between the tips of veins CuA and 1A (Christophers 1933). Christophers also noted a small pale spot dorsally on the midfemur, as in simlensis, which is not noted in Harbach et al. (2017). Additional study, especially of the probable types in the Natural History Museum, London (Townsend 1990), and the larval stage, are needed to better characterize this taxon. However, we think that its allopatric distribution in comparison to the other subspecies, the characters of the maxillary palpus and wing fringe, along with the dorsal spot on the midfemur (which needs to be verified) indicate that refutans is probably genetically distinct and should therefore be afforded species status: Anopheles (Anopheles) refutans Alcock, 1913 . Anopheles refutans is currently listed as a species in the Encyclopedia of Life.

There are four nominal members of the Gigas Complex in Sumatra. One, An. sumatranus, was elevated to species status by Harbach et al. (2017). Subspecies danaubento and oedjalikalah were both described from near Mt Kerintji. The type locality of subspecies danaubento is Lake Danau Bento [danau = lake, bento = a kind of grass] in North Kerintji in Central Sumatra. Verbatim coordinates of 1° 40′ S, 101° 16′ E are very close to the gazetteer entry for Danau Gunung Labuh (coordinates: -1.7381, 101.2673) and match the text description, “ Lake Bento lies at about 1400 m on the Southern Slope of Mt. Kerintji on the borders of Djambi and Sumatera Barat Provinces” (Kitzmiller 1982; D. Pecor pers. comm.). The type locality of subspecies oedjalikalah has verbatim coordinates of 1° 42′ S, 101° 16′ E. Oedjali Kalah is an old Kerintji word, which means Land of the Gods; situated on the southern slopes of Mt Kerentji, it was the source area of the Soengei Sioelak Deras. The elevation at this location is 1,451 m, which matches the locality description of 1,400 –1,800 m (coordinates -2.13333, 101.38333) (Kitzmiller 1982; D. Pecor pers. comm.). Subspecies danaubento and oedjalikalah apparently have sympatric distributions and there are no obvious diagnostic characters that distinguish them, though a minor character given by Nainggolan (1939), the apex of vein CuP dark-scaled in oedjalikalah rather than narrowly pale-scaled as in danaubento.

The third subspecies of the Gigas Complex in Sumatra is pantjarbatu, which was collected as larvae from undisclosed localities. Characters to distinguish it from the previous two nominal forms are weak and overlapping. The following table (Table 5) is derived from the tabular comparison of a few larval characters for these three Sumatran forms provided by Waktoedi Koesoemawinangoen (1954).

Given the probability that the three nominal forms are sympatric and there are no diagnostic characters to separate them, we conclude that they are conspecific and that allopatry and key morphological characters indicate the species is distinct from other members of the Gigas Complex. Therefore, subspecies danaubento is afforded specific status: Anopheles (Anopheles) danaubento Mochtar & Walandouw, 1934 , and oedjalikalah and pantjarbatu are hereby recognized as synonyms of that species: oedjalikalah Nainggolan, 1939 and pantjarbatu Waktoedi Koesoemawinangoen, 1954, junior subjective synonyms of Anopheles (Anopheles) danaubento Mochtar & Walandouw, 1934 . Anopheles danaubento is currently listed as a species in the Encyclopedia of Life. Subspecies oedjalikalah Nainggolan, 1939 and pantjarbatu Waktoedi Koesoemawinangoen, 1954, which are currently listed as species therein, need to be removed from the list of recognized species of the genus Anopheles.