Aedes (Ochlerotatus) caspius

Aedes (Ochlerotatus) caspius (Pallas) subspecies caspius (Pallas, 1771) —original combination: Culex caspius. Distribution: Afghanistan, Albania, Algeria, Armenia, Austria, Azerbaijan, Bahrain, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Djibouti, Egypt, Estonia, Finland, France, FYRO Macedonia, Georgia, Germany, Greece, Hungary, Iran, Iraq, Ireland, Israel (Gaza Strip and West Bank), Italy, Kosovo, Japan, Jordan, Kazakhstan, Latvia, Lebanon, Libya, Lithuania, Malta, Mauritania, Moldova, Mongolia, Montenegro, Morocco, Netherlands, Norway, Pakistan, Palestine, People’s Republic of China, Poland, Portugal, Qatar, Romania, Russia, Saudi Arabia, Serbia, Slovakia, Slovenia, Spain (includes Balearic & Canary Islands), Sri Lanka, South Sudan, Sudan, Sweden, Switzerland, Tajikistan, Tunisia, Turkey, Turkmenistan, Ukraine, United Arab Emirates, United Kingdom, Uzbekistan, Yemen (Robert et al. 2019; Wilkerson et al. 2021, incorrectly listed from Canada and the United States). subspecies hargreavesi (Edwards, 1920) —original combination: Ochlerotatus caspius var. hargreavesi (subspecific status by Harbach & Howard 2007). Distribution: Taranto, Italy [Puglia region] (Edwards 1920). subspecies meirai Ribeiro, da Cunha Ramos, Capela & Pires, 1980 —original combination: Aedes (Ochlerotatus) caspius meirai. Distribution: Cabo Verde [Cape Verde] (Republic of Cabo Verde) (Ribeiro et al. 1980). The nominotypical subspecies was described from specimens collected in marshes near the Caspian Sea (Pallas 1771). No type specimens are known but Edwards (1920) wrote that the species was first collected from the northern Caspian Sea in the marshes near the city of Guriev [Guryev], present day Atyrau, capital of the Atyrau Region, Kazakhstan. However, Edwards did not give a source for his information. Given that caspius is a complex of at least two species (see below), a neotype and complete description from topotypic specimens are certainly needed. Nominal caspius can be a very abundant pest. It is distributed throughout Europe, around the Mediterranean, the Middle East, Mongolia (Minàř 1976), China (Becker et al. 2020) and the northern sub-Saharan countries of Chad (Ndiaye et al. 2021), Mauritania (Mint Lekweiry et al. 2015) and Cabo Verde (subspecies meirai). Specimens from Mauritania “showed 100% homology [rDNA ITS2] with published Ae. (Ochlerotatus) caspius sequences from Italy.” Nominal caspius is halophytic, found in dryer climates, but it is also adapted to freshwater habitats. Predictive spatial modelling by Wint et al. (2020), based on specimens and literature, reflects the above distribution, which would be expected since it is based on combined data that includes cryptic species. The following are characters commonly used to identify the nominotypical form (after Becker et al. 2020 and Wilkerson et al. 2021). Adult female. Hindtarsomeres 1–4 with basal and apical pale bands, hindtarsomere 5 entirely pale-scaled; wing speckled with more or less evenly mixed dark and pale scales, costa predominantly dark-scaled; abdominal coloration highly variable, terga usually with median longitudinal pale stripe, tergum VII sometimes nearly all pale, or entire abdomen pale-scaled (variability documented in Toma et al. 2017) [associated with hotter, drier areas]; scutum fawn-colored [light yellowish tan], with a pair of narrow dorsocentral pale yellowish stripes [usually referred to as white] reaching to posterior margin of the scutum. Male genitalia. Gonocoxite with undivided basal mesal lobe (BML) [basal lobe of authors] gradually arising from the gonocoxite, bearing two closely approximated spine-like setae, larger seta hook-shaped and strongly curved apically (tip usually extending backwards to almost the middle of the seta). Larva. Body surface without spicules; antenna uniformly spiculate, seta 1-A 3–12-branched; 18–28 comb scales in triangular patch, scales pointed (median apical spine distinctly longer than the others, at least on some scales); siphon index 1.8–2.6, elements of seta 1-S with 5–10 branches, inserted beyond middle of the siphon, with about 20 evenly spaced pecten spines reaching to about mid-length of the siphon, base of siphon with acus; segment X (anal segment) with incomplete saddle, and ventral brush (seta 4-X) with 12–17 cratal and 2 or 3 precratal setae; anal papillae lanceolate, 0.3–0.9 length of the saddle. Edwards (1920) sought to define the nominate subspecies to separate it from closely related species, such as Ae. (Och.) dorsalis (Meigen, 1830) and Ae. (Och.) leucomelas (Meigen, 1804) [as salinellus Edwards, 1921b]. He described variation in a “Large series of this species [caspius]... recently... received at the British Museum from Italy, Macedonia, Palestine, Egypt and Mesopotamia, which show every gradation in the variation in the colour of the abdominal scales.... The thoracic coloration varies less; the two white longitudinal lines are nearly always present, though sometimes very narrow in two specimens from Italy, and in the type of G. longisquamosa [current synonym of the nominate subspecies], they are absent, the mesonotum then being uniformly fawn-coloured.” Edwards (1920) then named subspecies hargreavesi [as a variety of caspius] stating: “Among a series sent from Taranto, Italy (E. Hargreaves), are six females which have the whole of the central area of the mesonotum covered with whitish scales though in regard to abdominal markings they agree with moderately dark specimens of the species [caspius]. Nothing approaching this variation has been seen from elsewhere and it therefore seems justifiable to distinguish them under a separate name.” However, it is a bit puzzling that he also mentioned the pale lines as being absent in the type of G. longisquamosa. Harbach & Howard (2007) later elevated variety hargreavesi to subspecific status in accordance with Article 45.6.4 of the International Code of Zoological Nomenclature. The type locality of hargreavesi, Taranto, is a coastal city in southern Italy in the region forming the heel of Italy’s “boot”. We are not aware of further collections in that part of Italy and hargreavesi is usually only mentioned in lists. This leaves us without confirmation/refutation of its validity using other life stages and DNA. Townsend (1990) reported the presence of four syntypes in the collection of the Natural History Museum, London, which allows the possibility of DNA analysis. Edwards (1921d), in a revision of Palearctic mosquitoes, wrote that the basal lobe in the closely related Ae. dorsalis was “very prominent”, as opposed to “much less prominent” in caspius. The distinction is evident in an accompanying illustration. In Egypt, Kirkpatrick (1925) noted in a key that the basal lobe of caspius had two spines and that the appendage of the claspette was not keeled. This is in contrast to Ae. detritus (Haliday, 1833), which has a single spine and the claspette is keeled in the middle. Among specimens that Kirkpatrick otherwise considered to be caspius, he found two larval varieties. One with “Siphon about 2.3–2.6 times as long as broad; anal gills [anal papillae] longer than broad, two or three hair tufts [setae] outside barred area [grid] of ventral brush [precratal setae]. Aedes (Ochlerotatus) caspius.” The other with “Siphon about 1.9–2.0 times as long as broad; anal gills very small and round; ventral brush with four or five tufts outside barred area. A. caspius, larval variety.” Kirkpatrick (1925) described and illustrated the basal mesal lobe of caspius thusly: “Basal lobe rather large, triangular, with an almost straight spine [seta] rising from near its apex, and a longer stouter spine with a strongly curved tip rising at about one third of the distance from the apex; the basal lobe also bears a row of short straight bristles [setae].” A large triangular lobe and the row of short “bristles” are unlike what others had observed for caspius. Barraud (1934) likewise described and illustrated an apparently different basal mesal lobe: “coxite [gonocoxite] with pronounced basal [mesal] lobe carrying a strong bristly spine [seta] with hooked tip, one short spine, and a small number of flattened straight, bristles [setae]”. Flattened straight setae are not mentioned elsewhere in the literature. Marshall (1938), in The British Mosquitoes, described and illustrated all life stages (except the egg) in detail, seemingly in agreement with the general concept of caspius given above. Regarding the basal mesal lobe, he stated: “The basal [mesal] lobe of A. caspius carries a dense mass of bristles [setae], as well as two stout, conspicuous spines [setae]; the spine lying nearer to the base of the coxite [gonocoxite] being considerably longer than its companion, and having a markedly recurved extremity.As will be noted later, the hypopygium [genitalia] of A. caspius would be practically indistinguishable from that of A. dorsalis were it not for the fact that the basal lobe of the latter species is noticeably constricted at the base”. Clavero (1946) and Natvig (1948) also described similar characteristics of caspius from other European countries. Senevet et al. (1949) reported putative caspius specimens from three sites in French North Africa: Quargla, capital city of Quargla Province in the Sahara in southern Algeria; Salah, an oasis town in central Algeria, and Gabès, capital city of the Gabès Governorate, located on the coast of the Gulf of Gabès in what is now Tunisia. The Quargla specimens were different from typical caspius and different from specimens from the other two North African sites. “The scutum is absolutely devoid of the classically described white lines. It is completely and uniformly covered with tan [pale brown] scales. The basal mesal lobe is like the classical descriptions and drawings of Edwards [1921d], of Kirkpatrick [1925], of Barraud [1934], etc., and stands out only slightly, at a slight angle, covered

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