Culex (Microculex) imitator 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 : 102

Culex (Microculex) imitator Theobald

subspecies imitator Theobald, 1903a —original combination: Culex imitator . Distribution: Argentina, Brazil, Colombia, Ecuador, French Guiana, Guyana, Honduras, Lesser Antilles (includes Trinidad and Tobago), Mexico, Panama, Suriname, Uruguay, Venezuela ( Wilkerson et al. 2021).

subspecies retrosus Lane & Whitman, 1951 —original combination: Culex (Microculex) imitator retrosus . Distribution: Brazil ( Lane & Whitman 1951).

Despite being included in many taxonomic studies, Cx. imitator has only been superficially described, especially the larval and pupal stages. This also applies to subspecies retrosus , which has only been described once ( Lane & Whitman 1951; summarized by Lane 1953). However, Lane & Whitman provided distinctions, some unmentioned but illustrated, which seem to indicate that retrosus is a separate species. The differences include the following. In the male genitalia, ninth tergal lobe (as illustrated) short with relatively weak apical setae only slightly longer than the lobe (lobe elongate with strong apical setae about as long as the lobe in imitator ); subapical lobe of the gonocoxite (as illustrated) relatively long, setae a and b equally broad with narrow hooked apices, proximal side of lobe with a row of relatively long setae (lobe shorter, setae a and b constricted before short somewhat leaf-like apical segment, seta b distinctly stouter than seta a, proximal side of lobe with a row of relatively short setae in imitator ); basal hook of the lateral plate of the phallosome strongly curved/sharply bent (slightly curved, not bent in imitator ). In the larva, based on the “prothoracic hair formula”, seta 4-P 3-branched and setae 6,8-P 2-branched (seta 4-P 2- branched and setae 6,8-P single in imitator ). This, coupled with molecular evidence that Cx. imitator is a species complex in Brazil ( Demari-Silva et al. 2011), based on high intraspecific divergence (3.5%) in the mitochondrial COI gene and associated morphological differences in the pupal stage, we believe it is likely that further study will reveal retrosus is a separate species. Thus, retrosus is hereby elevated to specific status: Culex (Microculex) retrosus Lane & Whitman, 1961 . Culex retrosus is currently listed as a species in the Encyclopedia of Life.

Three nominal species are currently considered to be synonyms of Cx. imitator : Cx. daumasturus Dyar & Knab, 1906b (type locality: Trinidad and Tobago), Cx. vector Dyar & Knab, 1906b (type locality: Trinidad and Tobago) and Microculex argenteoumbrosus Theobald, 1907 (type locality: Rio de Janeiro, Brazil). It is possible the first two nominal forms represent a distinct species and the last one may be conspecific with Cx. retrosus , but we believe it is prudent to retain them as synonyms of Cx. imitator for the time being.