Nousia Navas 1918

Kluge, Nikita J., 2014, New subgenus and new species Nousia (Araucophlebia) latifolia subgen. n. et sp. n. (Ephemeroptera: Leptophlebiidae) from Chile, Zootaxa 3754 (4), pp. 483-490 : 483-484

Genus Nousia Navas 1918

= Atalonella Needham & Murphy 1924 Type species: N. delicata Navas 1918 .

Larva. Clypeus parallel-sided or slightly widened anteriorly ( Figs 1 , 24 ); labrum not widened, with median incision shallow or non-expressed; number of median denticles odd—5 or 3; both dorsal transverse setal rows straight and located near anterior margin, distal row very dense and irregular, proximal row more or less regular ( Fig. 1 ). Mandibles with outer margin smoothly curved, with hair tuft near middle ( Figs. 25, 26 ). Maxilla slightly broad apically, with 8–12 pectinate setae in ventro-apical row ( Fig. 27 ). Labium with glossae partly inserted in cavities of paragossae, not projected neither ventrad, nor dorsad of paraglossae ( Fig. 28 ). Patella-tibial suture developed on middle and hind legs, being absent on fore leg ( Figs 5–7 ). Tergalii of all pairs I–VII similar, each tergalius with both lamellae pointed, without additional processes; shape of tergalii varies from thread-like ( Pescador & Peters 1985: Fig. 54) to wide-lanceolate ( Finlay 2000: Fig. 23 ) or oval ( Figs 10 , 30).

Subimago. Pigmented area anteriad of mesonotal suture forms a narrow stripe along medioparapsidal suture ( Fig. 18 ). First tarsal segment covered with microtrichia; tarsal segments II–V covered with pointed microlepides.

Imago. Patella-tibial suture developed on middle and hind legs, absent on fore leg. On each leg both claws pointed. Hind wing without prominent costal projection and with subcostal vein long ( Fig. 20 ). Penis with peculiar structure ( Figs 13, 14 ): dorsal surface of each penis lobe crossed by a transverse semicircular ridge, with mediallydirected sclerotized process close to this ridge; unpaired proximal portion about 1/2–2/3 of total penis length ( Figs 12–14 ; Demoulin 1955: Figs 6 b', 7b', 8c'; Pescador & Peters 1985: Fig. 7 ; Finlay 2000: Figs 8 , 27 ).

Remarks. Among larval characters of Nousia , an enlarged distal denticle of the claw is mentioned ( Pescador & Peters 1985); in various species it is either strongly enlarged, or indistinctly enlarged ( Pescador & Peters 1985: Figs 50 and 48), or non-enlarged ( Fig. 4 ).

In the key to leptophlebiid genera of South America, Nousia imagos are separated from Penaphlebia Peters & Edmunds 1972 and Rhigotopus Pescador & Peters 1982 by the absence of a direct joining of vein ICu1 with vein CuA on the fore wing ( Domínguez et al. 2006). This statement is based on the diagnosis of Nousia by Pescador & Peters (1985), who stated that "vein ICu1 free or attached at base by a cross vein to vein CuA ... ". Actually, the vein ICu1 is often directly jointed with CuA ( Fig. 19 ; Needham & Murphy 1924: Fig. 97; Demoulin 1955: Figs 6 a, 7a, 8a) and occasionally can have a free base ( Pescador & Peters 1985: Fig. 1 ; Finlay 2000: Fig. 2 ) or be attached at the base by a cross vein to vein CuA ( Demoulin 1955: Fig. 9 ).

Subgenus Araucophlebia subgen. n.

Type species: Nousia (Araucophlebia) latifolia sp.n.

Diagnosis. Larval characters:

(1) Long spine-like setae on outer margin of tibia are present not only on hind legs, but also on middle legs ( Fig. 6 ) (in contrast to most other Leptophlebiidae ).

(2) Tergalii have dorsal lamella oval, with sharply separated slender apical process ( Figs 10 , 30). In other Nousia tergalii have both lamellae lanceolate and without terminal process ( Pescador & Peters 1985: Figs 51–54; Finlay 2000: Fig. 23 ).

(3) Denticles on posterior margins of abdominal terga I–IX are reduced. In other Nousia denticles on posterior margins of abdominal terga are well developed ( Pescador & Peters 1985: Fig. 58; Finlay 2000: Fig. 22 ).

Male imaginal character:

(4) Penis has simple outline of lateral sides; median sclerotized processes (peculiar for Nousia — see above) are massive ( Fig. 12 ). In other Nousia lateral sides of penis have protuberances, and median sclerotized processes are small ( Pescador & Peters 1985: Figs 6–13 ; Finlay 2000: Fig. 26 ).

Egg character:

(5) Eggs have unusual disk-like shape ( Figs 21–23 ). In other Nousia eggs have a usual ellipsoid shape ( Pescador & Peters 1985: Figs 56–57; Finlay 2000: Fig. 28 ).

Composition. One species, Nousia (Araucophlebia) latifolia sp. n.

Figures

FIGURES 1 – 2. Nousia latifolia, larva. 1, clypeus and labrum, dorsal view (setae of distal transverse setal row not shown, their bases shown as dots and their apices shown by interrupted line); 2, right half of hypopharynx and right superlingua, ventral view (1, holotype).

FIGURES 24 – 29. Nousia latifolia, larva. 24, clypeus and labrum; 25, 26, left and right mandibles, dorsal view; 27, maxilla; 28, labium; 29, hypopharynx and superlinguae; 30, tergalius of pair II (24 – 29 at the same magnification).

FIGURES 3 – 11. Nousia latifolia. 1, male imaginal abdominal tergum VI, spread on slide; 4 – 11, larva: 4, claw; 5 – 7, fore, middle and hind legs, dorsal view (thin setae not shown; cuticular coloration shown by dots; hypodermal coloration not shown); 8, right half of pronotum and mesonotum of exuviae of last instar larva; 9 – 11, tergalii of I, III and VII pairs (ventral lamella turned back).

FIGURES 19 – 23. Nousia latifolia. 19, 20, fore and hind wings; 21 – 23, egg from three sides.

FIGURES 12 – 18. Nousia latifolia. 12 – 14, genitals of male imago: 12, ventral view; 13, penis, dorsal view; 14, penis, lateral view; 15, posterior margin of sternum IX of male larva of last instar and larval protopenis, dorsal view; 16, posterior margin of sternum IX of female larva of last instar; 17, posterior margin of sternum IX of female imago; 18, subimaginal exuviae of mesonotum (12, 13, 18, holotype). P, small sclerotized process; R, transverse semicircular ridge.