Subgenus Nothoskusea Dumbleton, 1962
Opifex chathamicus (Dumbleton, 1962), original combination: Aedes (Nothoskusea) chathamicus.
Subfamily Culicinae, genus Opifex. Subgenus Nothoskusea is monobasic. Subgenus abbreviation – Not.
The only species of subgenus Nothoskusea, the largest mosquito in the New Zealand area, bears the following unique and distinctive features. ADULTS – Vertex of head with numerous erect scales; eyes widely separated, essentially as in subgenus Opifex; antenna with relatively small scape, flagellar whorls poorly developed, flagellomere 13 of females with apical process and few subapical setae; maxillary palpus very short, about 0.25 length of proboscis in both sexes; wing of females with setae at base of subcosta, absent or inconspicuous in males; all tarsi with rows of minute thorn-like setae among scales on ventral surface; ungues of all legs equal, toothed, with short spicules dorsally at base, essentially similar in males and females; abdomen of males distinctly longer than abdomen of females, terga and sterna II–VII with numerous setae and very sparse scales in both sexes. FEMALE GENITALIA – Largely retracted into segment VIII; tergum VIII about 0.65 length of sternum VIII, with a few scales on about posterior 0.4 and numerous setae on most of surface; sternum VIII with similar distribution of scales and setae, setae 1–3-S not distinguished, basolateral seta absent; tergum IX comprised of 2 lateral plates separated by membrane; cercus without scales, setae on about distal 0.8 of dorsal surface; postgenital lobe poorly sclerotised; upper vaginal sclerite striated; lower vaginal sclerite absent; insula lip-like, with 2–4 setae on each side of midline. MALE GENITALIA – Tergum IX lobes poorly developed; gonocoxite with long setae on lateral and ventral surfaces, mesal membrane poorly developed, narrow; gonostylus long, somewhat sinuous, gonostylar claw a short stout spiniform inserted at apex of gonostylus; claspette a prominent elongate setose lobe; aedeagus very small, simple; cercal setae short, 4–8 present. LARVAE – Prothoracic pleural setal group (setae 9–12-P) very small, mesothoracic and metathoracic pleural setal groups (setae 9–12-M,T) large, mesothoracic group borne far mesad of seta 8-M; seta 6-VI small, significantly shorter than seta 6-V; pecten not reduced, spines in continuous row or with gap near middle of pecten; seta 6-S inconspicuous; segment X with very small detached acus; seta 1-X not inserted on saddle; ventral brush (seta 4-X) usually with 9 pairs of setae. PUPAE – Cephalothorax with normally developed median keel; trumpet short, broad, trumpet index about 1.7; seta 1-I usually with fewer than 20 simple branches; seta 3-III inserted caudad of level of seta 5; seta 5-IV,V with 2–4 branches, usually triple; seta 9-VII large, dissimilar to smaller seta 9 on preceding segments, inserted dorsally at margin; seta 1-Pa usually branched. See genus Opifex.
The following characters diagnose subgenus Nothoskusea in the phylogeny of Reinert et al. (2009). ADULTS – Maxillary palpus of females without pale scales, males with palpomere 3 ≤ 0.14 length of proboscis and palpomeres 4 and/or 5 nearly straight; proboscis entirely dark-scaled, shorter than forefemur; scutal scales all dark, prescutellar area without pale scales on outer margin mesal to setae; postpronotal scales all narrow; mesepimeral scales in 2 patches; hindtibia with only dark scales, hindtarsomere 1 without basal pale scales; abdominal segment VII laterally compressed in females. LARVAE – Antenna with spicules, seta 1-A with ≥ 3 branches; seta 5-C branched; seta 6-C inserted at level of seta 7-C; seta 13-C branched; seta 8-P multi-branched (occasionally 3-branched); seta 1-M with ≥ 3 branches; seta 1-VIII 0.50–0.95 length of seta 2-VIII. PUPAE – Seta 11-CT branched; seta 1-Pa with ≥ 3 branches.
Subgenera Nothoskusea and Opifex were recovered as sister taxa based on two unique features of the antennae of males included in the phylogenetic study of the Aedini conducted by Reinert et al. (2004). Although Nothoskusea is currently retained as a subgenus of Opifex, phylogenetic analysis of New Zealand mosquito species based on rDNA ITS1 sequences (Cane et al., 2020) showed that Op. chathamicus may be more closely related to species of other aedines than it is to Op. fuscus, suggesting that Nothoskusea should perhaps be recognised as a separate genus in the phylogenetic classification of the Aedini. See the phylogeny of genus Opifex.
The immature stages of Op. chathamicus, the only species of subgenus Nothoskusea, have only been found in saline or brackish water rock pools at or just above high tide mark. Nothing is known about the adults as they have not been encountered in nature and are only known from reared larvae.
The only included species of subgenus Nothoskusea is not known to be of medical or economic importance to humans.
Chatham Islands.
Belkin, 1968 (as subgenus of Aedes, taxonomy, bionomics); Lee et al., 1984 (as subgenus of Aedes, taxonomy); Reinert, 2002 (as subgenus of Ochlerotatus, female genitalia); Reinert et al., 2004 (status as subgenus of Opifex, morphology, phylogeny); Reinert et al., 2006, 2008, 2009 (morphology, phylogeny).
chathamicus (Dumbleton, 1962)
